GB2340218A

GB2340218A - A cooling apparatus

Info

Publication number: GB2340218A
Application number: GB9922813A
Authority: GB
Inventors: Kazuo Kobayashi; Shigeru Kadota; Kiyoshi Kawaguchi; Tetsuya Takeuti; Takahide Ohara; Masahiko Suzuki; Hajime Sugito; Junichi Semura
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 1996-03-29
Filing date: 1997-03-27
Publication date: 2000-02-16
Anticipated expiration: 2017-03-27
Also published as: GB9922813D0; KR100259599B1; GB2340218B; GB2312499A; AU699379B2; GB2340218A8; CN1167249A; GB9706506D0; AU1660197A; BR9701588A; KR19980063276A; GB2312499B; CN1131988C

Description

2340218 COOLING APPARATUS USING BOILING AND CONDENSING REFRIG-RANT 71he

Present invention relates to a cooling apparatus usina b-cilinc; and condensing refrigerant, in which re-F-4gerant is boiled by he-;zt of a high temperature medium and is then condensed so as to radiate heat of the high temr)erature refricerant-. suc- as a cooling apparatus havJLng a thermosyr-hon type heat exchanger.

Conventionally, heating elements such as electronic parts are occasionally housed in a closed housing. In this case, as. a method for cooling the heating elements, there has been emcloved a method in which heat exc.qange is pertfor-med between air ins.Lde the housing and air outside the housing, because the outside air cannot be directly taken into the hous_ng so as to ventilate the interior of the housing. As a method for obtaining a small number of parts and a large amount 23 of heat movement, therd has been known a method using heat pipes (in which a refrigerant is sealed) disposed so as to pass through a housing, as disclosed in ITP-B2-2-3320.

7 n -the heat pipe as disclosed -L.-i JP-B2-2-3320, the ins;_de -efricerant is boiled by the h4;_c1t-.-_-e_i7.,perature -'.- the 2_5 hous-'nu, the refr-'gerant is condensed '_,y the _-adiat4nc port'-on dJ_sr.cse-_; outside the housing so as to radiate the heat, and the condensez' refrJaerant again drops into the heat absoriDing portion disposed within the housing.

However, Jin the heat pipe as d';_sclcsed in JP-B2-2-3320, vacor_zed ref--icierant which has been bci'.ed and rises and condensed refrigerant w'n';_ch has been condensed descends within the same Dioe. There-'ore, the _""Iowina directions c--" the refricerants are opDosez! to each ct-er, anz! there mav cause a nrotlem in that the ent--re r-e_'_-_zeran-zi does not circ-,:_-ate efficiently.

In view o." the foreaoina, t'nere illas been also kncwn a cooling apparatus usinq boil-'ng and condens--na refrigerant in which the heat can be efficientlv rad-4--t-ed -'-v ci--culatina t"e refrigerant, as in JP-U-62--116284-/ Accordinc to the coo-l-L'ng apparatus disclosed in JP-U-62-162S':7, a heatJ-na eleme--_ _Js secured-to a refrigerant tank, heat generated by the hea'ing fr4 element is absorbed bv a refriaerant se-aied in the re -gerant tank, the refriaerant boiled a:d vaporized by the lnea':

absor;D-Lion is condensed and lic,.:effied bv a radiator d4i-spose,-4 on the refr47erant tank, and tne condensed and lique-fled refrigerant is returned to the refraerant tank thrcuct a re-f--icerant. return Dipe _nserted into the ref-rigerant tan,,.

JP - 72 - 0' 2 - zowever, -4r. the coolinc apparatus:Jisclosed --"n t7' 162F47, s--'nce the refr4aerazn- ret',= pJpe for return-;-na:-e -e-17r-geran-t c-ndense-; bv the to the re-fr4cerant tank is inserted into the _-e_r_'aer_=n-L, t-e re-frigerant may be within the re-f-rigerant ret-_= p4:De beffcre returning back into t'n e r e f r -Laerant 'an--, the back into the refrigerant tank efficiently. As a result, there occurs a problem in that the refrigerant circulates slowly and the radJLating performance deteriorates.

Further, in the case where a massage for communicatIng between the refrigerant tank and the radiator is cooled when the refrigerant boiled and vaporized from the refrigerant tank rises to the upper radiator, the boiled and vaporized refrigerant is condensed in the passage and drops down be-'ore moving to the radiator. As a result, there occurs a problem in that the refrigerant circulates slowly and the radiating Derformance deteriorates.

Further, by the deterioration of the radiating characteristics, the cooling apparatus becomes large-sized.

The present invention has been accomplished on the -5 basis of the aforementioned circumstances. A first object of the present invention is to downsize the cooling apparatus by employing a new construction.

A second object of the present invention is to provice a cooling apparatus, capable of preventing the circulation of the refrigerant from being impeded.

t 4 A third object. of the presen nvention is to provide a coolina apparatus, having a low-temnerature-side co=unicat--on pipe for returning refrlicerant conc-'ensed by a ra6iat-or to a refrigerant tank and capabIe of preventing an occurrence of an ascending force of the ccn-_-_-.sed refricerant within -1ow-temr)erature-side communica-.--c.-i pipe when the heat_'na of the low-temperature-side communication z)i-,,e is heated.

A fourth object of the Dresent invention is to provide a cool..Lng apparatus, havina a hich-temoerature-side communi-cation pipe for sending refricerant boiled hv a refricerant tank to a radiator and capatle of Preven--ina vaporiLzed refrJ,-cerant from beinc: ccndense--4 within the temnera!_--ure-side commun.4Lcation p1pe wl-.en the co--linc cf the high1---em;-,erature-side corununication pipe is cooled.

According to an aspect of the present invention, a refrigerant sealed in a refrigerant tank receives heat off a high-temperature portion and becomes boiled and vaporized. --he boiled a-nd vaiDcrized refricerart ascends and flows into a radiator. In the radiator, heat o-i'-' the vaporized refrigerant is radiated to a low-temperature portion to condense and liquefy the refrigerant. The condensed and liquef_-ed refr4Lcerant returns to the refrge-ant tank throucl a communication DiDe and -receives heat again. in the prese-t inventio.-, the cii--culation of the refriaeran- is)revented from being i_mpeded in order t1--at a heat concluct-'on between ei-:'-er one of the refr4;_crera-,: tank, the ra-__iazor, the h1ch temperaz'_:re ocrtion ard the lower tem:)erazure Dortion, and the tea,::

ccnduc-_-cn to the cc =,.::_'ca-iicn c- pe is s-.:rpresse-_ by ccnduc-_,'cn suppressing -ne-ans.

That 'Ls, when tne teat sL::;r_ s-cr,resses --'-e heat co-,_-uC-__-on bet_-ween the communication pipe, the descending refrigerant which has been condensed and liquefied by the radiator absorbs high temperature heat from the refrigerant tank through the CoMMUn -cat ion pipe to prevent from receiving the ascending force within tne communication PiDe. When the heat conduc:_'cn suDnress-ILnc means suppresses the heat conduction between the high temperat,,ire portion and the commulnicat-Ion pipe, the descending ref-rIgerant which has been condensea' and liquefied bv the radiator abscrbs heat from the high-temperature through the communication pipe to prevent from recelving the ascending force within the communication pipe.

Further, when the heat conduction suppressing me-ans suppresses the heat conduction between the radiator and the communication pipe, the ascending refrigerant which has been boiled and vaDorized in the refrigerant tank can be preven'::ed from descendinc within the communication r)iTDe-bv radiatina heat to the 1ow-te=)eratu_-e radiator through the communication pipe.

Furt)-ier, when the heat conduction suppressing means suppresses the heat ccnduction between the low temperature portion and the 2C communication PiDe, the ascendina refrigerant which has been bo-i-lea-3 and vaporized in the refrigerant tank can be preven'::ed -rcm aescending within the communication plipe tv radiat-Lno he-;z- to the 'Low-temperature portion through the coam un icat _O.j P,.-,= As a resu- since the radiat-'on can be)er-fo_=e,_4 the cooling apparatus can be downsize,_J.

Acccrdirc to another ascect of': the inventicn, -e refri-erant sealed in-0 the refriaerant t-ank receives lne=- cf t! L a high-temperature flu _Jd and becomes boil ed and vaporized. The boiled and vaporized ref--:gerant s de 4 vered to a radiator disposed away from a fluid separatira plate. - 7 n the radiator, heat of the refriQer-=n-i -'s radLated to a low-temDerature fluid so as --c be condensed and licTuef-'ed -.'-e ref_-iqerant. The condensed and Iiauef4,_ed --efricerant returns to the refr 4 gerant tank throua,. the comirunication c4,,,e and receives heat acain.

7n this wav, it is possJl-_e to prevent the c4rculat-4--n of the refricerant from beinq impeded, si-nce the heat conduc,i_'Lon between either one of the refricerant -_ank, the radiator, the nI low-temperature port' ich-temz)erature portion and the L ion,and the ccmmunicat'Lon pipe is suppressed by the heat conduc,:j_on S 4 suoDres -1-na means.

The heat conduction suppressIng means may be a refricerant tank-s-:;_de heat insula-_'ng mater'ai disposed between the refr-:cerart tank and the low- temperature-s 4Lde communica--ion pipe and formed of a heat insulating mat-er.41-a-11 in this way, the heat conduction from the refrigera--i tank, to -he low temuerature-side communication pipe can be suppressed. S a resul t, it is Dossible to prevent the descending refrigerant wn-1ch has been condensed and liauefied 1--y the radia,:or from abso_-bina hea- from 'he hiah-temcera-:iure ref--iceranr- -tank througn the ccmmun_'ca-r_-_-cn piz)e ana recea-,.7ing -ihe ascena;inc:

4 7 force _n the _ow--_empera-.ure-s-;,::, co=unicazion p --pe.

2 5 c c o r --; i n c: is:)ossilDle t3 zrevent the circulaticn Of --f-geran- frcm be-no 4-mmeded, a:-i- the cccl_na apza--atus can be downsized.

The heat conduction suppressing means may be a radiator-side heat insulating material disposed between the radiator and the high-temperature-side con-nunicat-ion pipe and formed of a heat insulating material. in this way, it, is possible to prevent the ascending refrigerant which has been boiled and liauefied in the refrigerant tank from radiating heat to the low-temDerature radiator throuan the communicat-ion pipe and descending in the communication pJL:)e. Further, it is t 4 poss4l-ble to prevent the circula -Lon of refrigerant from being imDeded, and the apparatus can be downsized.

The heat conduction suppressing means may be a high temperature portion-side heat insulating material covered on an outer periphery of the low-temperature-side communication pipe and formed of a heat insulating material. In this way, it is possible to suppress the beat conduction from the high temneratu_-e portion to the low-temperature-side communication pipe. As a result, it-is possible to prevent the descending refrigerant which has been condensed and liquefied in the radiator from absorbing heat from the high-temperature portion 2 0 through the low-temperature-side communication pipe and receiving the ascending force in the low-temperature-side cc,mmunication oiDe. Further, it is possible to prevent the c_4r-_,,:_'at_4on oJL' refrigerant from being impeded, and the cooling acparatus can be downsized.

2_5 The heat conduction suooressina me-=ns may be a 'Low L-e:-,perature por'_ion-side heat insulating material covered or. an ouzer periphery of the high-temperature-side com:municaticn pipe and fo=ed of a heat insulating material coated. In this way, it is possible to prevent the ascending refrigerant which has been boiled and vaporized in the refrigerant tank from radiating heat to the low-temperature portion through the high temDerature-side communication r)i--e and descending in the high temDerature-side communication pipe. Further, it is pcssJL-ble to prevent the circulat'Lon of refrLaerant from being LT.Deded, and the cooling apparatus can be downsized.

Further, t-e above heat insulatina material mav cover at least a part of the outer periphery of the low temnerature-s'Lde communication pipe or the high temperature- side communication pipe. In this way, 3-t is possible to prevent the circulation of refrigerant from being i-mpeded,-and the cooling apparatus can be downsized as compared with prior art.

Still further, the above heat insulatLng material may cover the ent-'re outer pe--iphery of the low-temperature-side communication pipe cr the high-temper-ature-side commun_Jca-:_ion pipe. In this wav, it is possible to further prevent the circulation of refrgerant from being impeded, and the cool-4ng apparatus can be dcwnsized as comparec; with the Qrior art.

Further, the heat insulatina material mav be formea; Of' a foaming resin; and there-fore, neat insulation can be ef f C 4 performed e n t 2 5 The heat c,-nduct-'cn sunc.-essing means may inclucie a huh-temDerature-s_'de oartizior membe_- for r)art_4-__4onJnq a h4ah temperature passage with t!e fl,-lic! separat_4na p1ate so that the low-temperature-side communication pipe is separated to a region, a temperature of which is lower than that in the high temperature-side passage. It is possible to suppress the heat conduction from the high-temperature passage to the low temoerature-side communication pipe. As a result, it is possihle to prevent the descending refrigerant which has been condensed and licTuefied in the radiator from absorbing heat from the high-temperature passage through the low tempera--ure-side communication pipe and receiving the ascending force in the low-temperature-side communication pipe. In this way, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized.

Further, the heat conduction sur)pressing means may include - a low-temperature-side partition member for partitioning a low temperature passage with the fluid separating plate so that the high-temperature-side communication pipe is separated to a reuion, a temperature of which is higher than that in the low- temperature-s ide passage.

In this way, it is possible to prevent the ascending 2C refrigerant which has been boiled and liquefied in the -efr-;geran- tank from radiating heat to the low--emDerature passage through the high-temperature-side communication pipe and descending in the high temperature-side conniunication pipe.

7n this wav, it is possible to prevent the circulation of refrigeranz from being impeded, and the cocling apparatus can be dcwnsized.

Furt'"er, a Dluralitv of boiling and cooling units are disposed so that refrigerant tanks are disposed in parallel with each other and radiators are disposed in parallel with each other. In addition, there may be provided a high temnerature-side partition member for partitioning a high temDerature passage wit'- the fluid separating plate and a low temperature-side partition member for partitJLoning a low temDerature passage with the fluid separating plate, and the low- temQerature-s ide communication pipe is separated to a region, a temperature of which is lower than that in the high temperature passage by the high -temperatureside partition member and the low-temoerature-side Dartition member and the high- temperature- s id e communication pipe is separated to a region, a temperature of which is higher than that in the low temperature passage. In this way, the heat transfer from the high temDerature passage to the low-temperature-side communication pipe and the heat transfer from the high tempera ture-side communication pipe to the low-temperature passage can be suppressed. respectively.

As a result, it is possible to prevent the descendinc refrigerant which has been condensed and liquefied in the radiator from absort-inc heat from -:he,_gh-temzerature passage throuch the lcw-temDerature-side con-aunication pipe a n -_ receiving the ascendina force in the low-temperature-side - S a7SC) conununicaticn pice, and 1E pcssltle to preven-_ the 4 igerant whiCh has been boiled and vaoor]Lze,_- in t1n-e to the lcw-teM.=erature refrigerant tank 'r--m ra,_44Latina he=-L passage tnrcuc'n the h-zh-temT:)erat-,:re-si,_Je ccmmunication 4De and descending in the high- temperature-side communication pipe. Accordingly, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be dcwnsized.

iCat4on The low-temDerature-side commun pipe may be disposed substantially in parallel witll the heat absorbing pipe so as to communicate a heat absortina-s4L_de lower communication Dortion. with a radiating-side lower communication portion, and tl-,4e high-temperature-side communication pipe may be disposed substantially in parallel with the radiating pipe so as to communicate a heat absorbing-side upper com.munication portion with a radiating-side upper commun-iLcation portiLon. Since the heat conduction suppressing means may be provided on the low -LemDerature-side communication pipe or the high-temperature side communication pipe, it is possible to suppress the heat conduction from the refrigerant tank to the low-temperature side,. or the heat conduction from the hich-temDerature-side communication pipe to the radiator. As a result, it is possible to prevent the descending refrigerant which has been condensed and liauefied in the radiator from absorbing heat from the tigh-temperature refrigerant tank through the co,amurlcation pipe and receiving the ascena4ing force in the low-t-_.T.Derature-sJLde communication;4De. 7- 's possible to L - - preve-z the ascending refrigeran-:i which has teen bo4lec anci va:)or;zed in the refrigerant tank from racila-.1na heat to the lcw-z_eir,:-,era-,,:re radiator throuan the co=nJcat4o- 04pe an L descen--4-4ng _n the communicat.Lon pJLpe.

in this wav, it is possible to prevent the circulation of refricerant from be';_ng impeded, and the cooling apparatus can be dcwnsJ_zed.

AdditLcnal ob-eczs and advantages o f t I,. e present 4nvenzi-cn will be more readilv apparent 'rom -he fC",,cwiT-),- _L - - - - Ij detailed description cf iDreferred emtodiments thereof when taken toget'- er w-'--,i the accompanying draw-Ings in which:

FIG. 1 is a s4Lde view of a casing cooling apparat-s used for a cooling apparatus using boiling and condens JLng refrigerant according to a first embodiment; FIG. 2 is an explanatory schematic view of the cooling apparatus shown in FIG. 1; FIG. 3 is a perspect-Live view showing the COC14 In a apparatus accordinu to the first embodiment; FIG. 4 is a front view of the cooling apparatus shown in F IG. 3; FIG. 5 is an exr)lanaterv schema t 4 C view of the coolina 2C apparatus shown in 7T,-. 4; I-, - FIG. is a cross sec-ional v_e-,; taken alona the I ine jj_,7j 0,;: rTG.

vlew snowirg a modi--, exa-r-,D-e of --he cool-'.-g. ancaratus slo,,n in FIG. 6; --:'T - CO-14 2 1.:. 8 -is a side view of a cooler usLng the _nc:

acDara-ius accordina to a second emto"_'ment; i- a front v4ew of tne cooler accord_nc tc the second embodiment shown in FIG. 8 FIG. 10 is a perspective view showing the cooling apparatus according to the second embodiment; FIG. 11 is an enlaroed view of a heat absorbing pipe of the cooling apparatus shown in FIG. 10; FIG. 12 is a cross sectional view taken along the 14 ne L XII-XII of FIG. 10; FIG. 13 is a cross sectional view showing a modification of the cooling apparatus shown in FIG. 12; FIG. 14 is a side view showina the whole of a cooling system according to a third embodiment; FIG. 15 is a vertical cross sectional view of a refrigerant tank; FIG. 16 is a transverse cross sectional view of the refrigerant tank taken along the line XVI-XVI of FIG. 15; FIG. 17 is a cross sectional view of a heat radiator taken along the line XVII-XVII in FIG. 14; FIG. 18 is a partial cross sectional view of a refrigerant tank, showing a heat transfer decreasing structure according to a fourth embodiment; FIG. 19 is a partial cross sectional view of a refrigerant tank, showing a heat transfer decreasing structure accord4n= to a fifth embodiment; FIG. 20 is a partial cross sect'onal view of a refrigerant tank, showing a heat trans.-fer decreasing structure accordina to a sixth embodiment; FIG. 21 is a partial cross sectJlcnal view of a refrigerant tank, showing a heat transfer dec-reasing structure according to a seventh embodiment; -7C- 22 is a vertical cross sect4onal view of a refricerant tank accor'-ina to an eighth enitodiirent; F I C- 23 is a vertical cross sec--4onal v4;_e,,; of a refricerant tank acccrdinq to a n.Lnth embo--4-inent; a vertical cross sectional view cf a refr'Lgera-- tank acco--dinc to the ninth em'--odimen-; 7TG 25 is a vertica.1 cross sect-Lonal view c-f a refrigerant tank according to the ninth embodiment; FIG. 26A is a cross sectional view showing schema---ically a structure of a hea-- exchanger used in a cooling aFparazus, and FIG. 26B is a schematic diagram showinc: a schemat--c structure of the heat exchanger, according to a tenth embodiment; FIG. 27 is a schematic diacram s-owina the entire structure of an elec-rcnic apparatus acccrding to the tenth embod iment; FIG. 28 is a front view showing a structure o-f a C0014.na Un4t accord-inQ to the tenth emcdiment; FIG. 29 is a persr)ec----'ve showing a flluid senara--ino pla-e which d4;_%;-ides the cool-'nc: un--,- into FTG. 3C is a perspec-47.-e f = f", ' ": -I Cl T, 1 a t e which --4 i v i d e s the ccol 4 rc un, t ntD two acccrdi-g tz the tenth er-,bod-lr-,,en--; schematic ciiacr-=m shc-,,;--nc a distribution in flowing directions of air and a refrigerant according to prior art, and FIG. 31B is a schematic diagram showing a temperature distribution in flow4Lng directions of air and a refrigerant in the tenth embodiment; FIG. 32 is a cross sect-lLonal view showing a concrete structure of a cooling apparatus according to an eleventn embodiment; FIG. 33 is a front view showing a structure of the cooling apparatus according to the eleventh embodiment; 1 C, FIG. 34 is a rear view showing a structure of the cooling apparatus according to the eleventh embodiment; FIG. 35 is a front view showing a structure of a cooling unit according to the eleventh embodiment; FIG. 36 is a cross sectional view showing a schematic structure of the cooling unit according to the eleventh embodiment; FIG. 37 is a front view showing a structure of a Cooling unit according to a twelfth embodiment; FIG. 38 is a perspective view showing a sealing structure in a heat exchanger according to the twelfth em!Dodiment; F 7 G. 39 is a cross sectional v-Lew showing the sea7ing str'ac'ure in the heat exchanger of the twelf-th embodiment; FIG. 40 is a sectional snowinq a concrer-e str',.:c'=e of a cooling system accordLnc --o a thirteenth e:r,L,,od 4 ment; FIG. 41 is a front v4:_ew show-4-g a main structure of- a fluid senarating plate used in a heat exchanger according to the t.1-irteenth embodiment; FIG. 42 is a cross sectional view showing a structure of a cool-ing svs-Lem according to a -fourteenth embodiment; FIG. 13 is a front view showna a main structure of a fluid senara-ing pla--e used in a heat exchainger acccrdina to a fourteenth emtodiment; FT-. 44 is a cross sec,ional view showing a structure of a coo-',4L-g apparatus of a flfteenth em.nodiment; FIG. 45 is a front view showing a main structure of a fluid separating plate used in a heat exchanger acco.-ding to a fifteenth embodiment; FIG. 46 is a schematic view showing the ent-'re structure of an electronics apparatus according to sixteenth embodiment; FIG. 47 is a cross sectional view showing a detailed structure of a cooling apparatus; FIG. 48 is a front view showinc7 a detailed structure of the cool'nc apparatus; 2C 7TG. 49 is 'ew showina a detailed structure of a rear vi t,-- coo', ra appa-rat--us; 711. 50 is a 'ron- v-e,,; s--wina a de,-a4led the Cocling unit; FIG. 51 is a cross sect-'ona" v-,ew s1nowna a -ta--ted the cocl--nc unit; 5:2 -Ls a -front vie-,; snowInc a structure of an electric heater mcuntinq apparatus; FIG. 53 is a side view showing a detailed structure of the electric heater mounting apparatus; FIG. 54A is a front. view showing a detailed structure of an electric heater, and FIG. 54B is a side view thereof; FIG. 55A is a front view showing a detailed structure of a bracket and a guide shaft, and FIG. 55B is a side view thereof; FIG. 56 is a schematic view showing the entire structure of an electronic equipment apparatus according to a seventeenth embodiment; FIG. 57A is a sectional view showing a schematic structure of a heat exchanger of a cooling apparatus, and FIG.

57B is a schematic view showing a schematic structure of a heat exchanger of a cooling apparatus according to the seventeenth embodiment; FIG. 58 is a front view showing a detailed structure of a cooler according to the seventeenth embodiment; FIG. 59 is a perspectJLve view showing a fluid separat]Lng plate for dividing the cooler into two portions according to the seventeenth embodiment; FIG. 60 is a perspect4Ve v4ew showing a flu'd separat.na plate for dividing the cooler into two portions acco-dina to the seventeenth embodime-t; FIG. 61A is a schematic V4_W Sho,jng the temcer-;-t'-7re in flowing directions cf air and refrigerant accordina --o- prior art, and FIG. 61E is a schematic view s'ncwina the temnerature distribut-4cn in flowinc direc-'ors of air and refrigerant according to the seventeenth embodiment; Z 7G. 62 is a cross sectJonal vJew showing a detailed structure of a cocling apparatus according to an eighteenth emboc-'ime"t; 7 T C -. 63 is a front view slinowing a detailed structure of a coolina acnarat--:s according to the eia'nteenth embodiment; FIG. 64 is a rear view snowing a Je-ailed structure of:

a COCIlLng system acco--di.ng to the eighteentn embo"-Iment; 7:,G. 65 is a front view showing a detailed structure of a cooler acccr,-4ina to the eighteenth embodiment; F 7 G. 6 6 4 Is a cross sectional view showing a deta-'ed structure of a cooler accordinQ to the e-ichteenth embodiment; FIG. 67 is a front view showina a detailed structure of a cooler.accordinq to nineteenth embodiment; FIG. 60' is a schemat-'c dagram showing the ent--re structure of an electronic aDoaratus ac-cording to a twentieth embodiment; FIG. 69 is a cross sectional view sh--wina a st--.=ure of a coolina acDaratus accordinq to the twentieth embodLm.ent; FIG. 70 is a cross sectional view shcwna an u,,:Der structure of tne coc-'--ng aDr-arat,,:s accor--4--ing to t',. -h .e twentie- embodiment; 77G.

a cross sect--onal view showing a szruct":re -f z-e coc-'--':-c appara-:,-ls accord-ncT tc the ':wen,:-'eth embodii-,ent; F 7 7- a cnview s--wnc a concre-e str--:c-:ure of - i 8 - FIG. 73 is a rear view showing a structure of the cooling apparatus according to the twentieth embodiment; FIG. 74 is a front view showing a structure of the cooling apparatus according to the twentieth embodiment; FIG. 75 is a cross sectional view showing schematically a structure of the cooling apparatus according to the twentieth embodiment; FIG. 76 is an exploded view showing a structure for mounting a low-temperature-side centrifugal!Dlower according to the twentieth embodiment; FIG. 77 is a cross sectional view showing schematically a structure of the low-temperatu--e-side centrifugal blower according to the twentieth embodiment; FIG. 78 is a cross sectional view showing schematically structure of a low-temperature-side centrifugal blower according to a twenty-first embodiment; FIG. 79 is a diagram showing a side plate of a drive motor and a heat transfer accelerating plate according tc t1lie twenty-first embodiment; 2 0 FIG. 80 is a cross sectional view showing schematically a structure of a low-temperature-side centrifugal blower accordina to a twenty-second embodiment; FIG. 81 is a plan view showing a centrifugal fan si:nporting plate according to -the twenty-second embodiment; 2 _5 FIG. 82 is a cross sectional view showina schematically a structure of a low temperature-side centrifucal blower according to a twenty-third embodiment; FIG. 83 is a cross sectional view showing schematically a structure of a low-temperature-side centrifugal blower accord.Lnc to a twenty-fourth embodiment; FIG. 84 is a mountinc diacram showinQ a main struc:ure of the low- temperature- side centrif,,:aal blower accorciing to the twent:y-'Lourth embodiment; FIG. 85 '. Ls a cross sec-ional view of a housJLng equLpped wi-:h a cool-ing apparatus accorcing o the twenty--fifth embod 4 ment; FIG. 86 is a front view of the cooling apparatus according to the twenty-fifth embodiment; FIG. 87 is a side view of the cooling apparatus according to the twenty-fifth embodiment; F7G. 88 is a view of the cooling apparatus as seen from below according to the twenty-fifth embodiment; FIG. 89 is a detail view of a connection in the cocling apparatus accordina to the twenty-fifth embodiment; V 4 FIG. 90 is a detail -ew of a refrigerant 'Ln the cooling apparatus according to the twenty-fifth embodiment; FIG. 91 is a detail view of a connection in a coolina a-.Daratus acccrding to a twentv-sixth embodiment; anci FIG. 92 is a fron, view of a modif ication of t.',e cooling sys--em. There now follows detailed oescription of the preferred embodiments.

A emboldimen-_ of -_,.e::resent Invention wil-- be descri,ed.

FIG. 1 is a side view in which a cooling apparatus 1 using boiling and condensing refrigerant is applied to a box shaped cooling apparatus, and FIG. 2 is an explanatory schematic view of FIG. 1.

In this embodiment, as shown ':_n FIGS. 1 and 2, a closed space 9 is a space formed by a casing 80. In the closed space 9, there are accommodated a heating element 7 (for example, a trans-receiver for communication ecuipment, and a power amDiifier for actuating the trans-receiver). The closed space 9 is provided at upper and lower portions with openings communicated with coolers 81. The cooler 81 is formed with a vent port 13 which is communicated with 'the upper porticn of the closed space 9 in order to introduce gas of the closed space 9 into a heat transfer space I1 on the high-temperature side. More sDecifically, one side wall surface 9a forminq the closed space 9 and a partitioning wall 22 provided within the closed space 9 form an air passage 23 vertically extending into the closed space 9, and the upper end of the air passage 23 is opened to the upper portion in the closed space 9 (above a fluid separating plate 2) as the vent port 13.

In this way, the gas having a high temperature, he-ated by the heating element 7, is introduced from -the vent Dort 13 into the air passage 23 and led in-zo a re fr.-ig era n-,.-- tank 3a smoct'"ly' and a temperature in the closed space 9 can be mai.-tained uniform. That is, since the gas having a high tempera-:=e, due to the heat generated -From the heating element 7, mcves upward within the closed space 11, 'ny convection, _;_n order c imDrove the cooling efficiency in the closed space 8, it is preferable for the vent portion 1-3 to be provided at the unDer part of the closed space 9. In other words, when the vent oort 13 is located lower than the fluid separatnc plate 2, a relazt_velv low- tempera ture gas in the closed space 9 is in-z=d,.:ce-_; from tle vent port 13 into the air assage 23 and led to the re-f-ricerant tank 3a, and the Cool]-na ef_'.Lciencv in the c_'cse-:i space 9 is not sufficient.

Further, t-.e high-temperati_:re 'lu4d unifcrmlv flows into the refrigerant tank 3a by form-'ng the air passage 23. In the case where the air passage 23 is not provided, a flow becomes concentrated in -the vicinitv o--'r the lower portion of the re-fri-aerant tank 3a, which is the closest to an in-:ernal fan 15,. and the heat absorbing efficiency deteriorates.

However, the high- temperature air easily passes through the unDer Dor-::ion cf the ref:rigerant -tank 3a by forming the air passage 23.

Further, in the this embo-_Lment, the entire C_C7 ing apparatus 1 is dispcsei so as to be inclined in a lateral directlon (the left and right direc,iion in FIG. 2) so tl-at the gas passing throucn the refrigeran-_ -Lank.3a and a radiazor 3b wi-,_-hin the heat trars-fer snaces 11 and 1-2 on the h-'-;- and I ow temnerat--ure-si-des smoothly -flow from the vent ports 12 and 1-16 on the sL:------'on s-'de toward the vent purts 14 :n t'-I--s wav, the c-ance in -f:low _-_ifection of t',e c:as -flowing t-rouch the re--=ierant tank 3a anl_ the ra,"-4 iat:r can be slackened so -.-;at tl-e loss ofl: the alf in the narrow space can be reduced. As a result, the internal fan 15 within the closed space 9 can be downsized, and the heating amount generated by the internal fan 15 can be reduced so that the same amount of heat generated by the heating element 7 can be increased (that is, when the internal fan 15 becomes large-sized to improve the cooling performance, the heating amount generated by the internal fan 15 increases, and as a result the heating amount the heating element 7 cannot be increased).

A controller 82 controls the rotational speed, operating time and operating pattern or the like of the internal fan 15 on the basis of a temperature of air flowing into the vent port 13, which is detected by a temperature sensor 8.4. When the closed space 9 is at a high temperature, the internal fan 15 and an external fan 18 are actuated to lower the temDerature in the closed space 9, while when the closed space 9 is at a low temperature (in cold season), the internal fan 15 and a heater 19 secured to a cooler wall 83 are actuated to adequately control the temperature in the closed sDace 9.

FIG. 3 is a perspective view showing the cooling aDDaratus. FIG. 4 is a front view of the cooling apparatus show,n in 77G. 3, FIG. 5 is an exDlanatorv schematic view of F 7 G. 4, and FIG. 6 is a cross sectJ_onal view taken along the 2_5 line VI-Vi of FIG. 3.

in this embodiment, as shown in FIG. 3, a Dluralitv of ccoling apparatuses using boiling and condensing refrigerant are stacked in flowina directions of high-temperature fluids and low-temperature fluids.

As shown in FIG. 5, the cooling apparatus 1 includes a fluid separating plate 2 for separating a higll,,--Lemperature fluid (for example, h4gh-temperature a ir) f ron, a low temDerature fluid (for example, low-temperature ai--,,; a refricerant tank 3a composed of a plurality o-f heat abscrh)ina pipes 31a disposed on the high-temnerature fluid side from the fluid semaratinc Diate 2; a refrigerant sealed into the heat absorbing p_'pes 31a to receive heat from the higt-temperature fluid so as to be boiled and vaoorize-_4; a pair of low temperature-side communication pipes 34a, one of which is communicated with the refrigerant tank 3a hermetically w_ile the other being passed through the -fluid separating plate 2 and extended to the low-temperature fluid side; a communicati-on pipe 34b; a low-temperature side communication pipe 34a; a radiator 3b communicated with the other of the high-temperature side cominunicaticn pipe 341D hermet41-cally and composed of a plurality of radiating pipes 31b disposed on the low temperature fluid side f --orr. the fluid separating plate 2; a heat receiving fin 6a jo'=ed in a 'LL:sed state (for example, in a brazed state) between the neat a_Dscrb4Mg pipes 31a of the refricerant tank 3a; a radiating f_'n 6b joined in a fused state (fcr examr-le, in a brazed sta-:e) between the radiating plDes 2 _5 31b of the radiator 3b; and a hea, insulat-ing material 50 for examnle,.:rethane fcam wh--ch is a foaminq resin) as a heat conduction suppressing means embedded between the refrigerant tank 3a and the low-temperature-side communication pipe 34a and between the radiator 3b and the communication pipe 34b to suppress the heat movement from the refrigerant tank 3a to the low-temz)erature-side communication pipe 34a and the heat movement from the radiator 3b to the corrununication pipe 34b.

in FIG. 5, the air flow direction of the low temperature fluid and the high-temperature fluid is ind4.cated in the lateral direction on paper for the sake of convenience, however, actually air flows in the laminating direction -in -_ TG.

3.

The fluid separating plate 2 constitutes, for example, one wall surface of the closed space, an interior of which is at a hiah temperature, and is formed of metal material such as aluminum. and joined integrally (for exam.ple, brazed) to the low-temDerature-side communication pipe 34a and the hich tempera tu re-s ide communication pipe 34h. The fluid separat4na olate 2 is bored with an elongated insert hole through which the low-temDerature-side communication D41-De 3.4a and the hich temperature-side communication pipe 34b extend. A resin such as rubber for suppressing the heat movemen' may be held between the fluid separating plate 2 and each C C,-p _ _. 4 1U, _LcatJon p'Lpe.

7ur-her, -he fluid separat-ing plate 2 may be heat-insulated L from the periphery (at least one of the low-zemDerature fluid or the hi=h-temDerature fluid) by the he=--!-- insulating material 4:

formed o'ff a foaming resin such as urethane ffcam.

The refrigerant tank 3a includes a pl,.:ral_Jtv of heat ahsorbina Dipes 31a disposed substant-4ally in parallel, a heat absorb inc-side lower ccmmunication portion 41 disoosed below the heat absorb_na pipes 31a ccr-mr.un-4--ated with these heat absor__-.-q D'Lnes 31a at the lower pcrzicns thereof, and a heat absor-1--ina-sIde upper cc=unication port_on 42 disposed above the heat abscrbinc D-4ces 31a co:=u-icated with these heat abscrD.Inc pipes 3la a-, the upper pCr-__4cns thereof. The heat atsor'--Ina zi-,e 31a is in the form of a -flat PiDe having an elonc-;z-::ed --ectancular (or an c,.,-al) cross section and Is made of a met;: 7 mater_all ( for examcle, alumInu-, or copper) wltlic.". is superlor _'In heat transfer characterist--cs.

The radiator 3b includes a plura.-Lizy of radiating pipes 31b disr)osed subs tant -4al ly,-n)aralle_' with each other, a radiatna-side lower ccr=,unication Dortion 43 disposed below t 4 the radiating pipes 31b and coinmunicated with the radia na pipes _31h at the lower ocrtions thereof, and a radiating-side L _L - I upper cc=unication portion 41T disposed above the raCi_'ating pipes 3lb and co=unicated with the r_=6iat-ing pipes 31t at the upper portions thereof". The radiating pipe 31b is alSC in the -o= of a flat pipe hav'na an elongated rectangular (or 2 C) oval) crcss section an--4 is made cf a metal materai e,xair,TD!e, alumi The. _,c;h-_--_.Tnerature s ije ccmmun icat ion. iD i:)e 3 '1-'- is upper cc=.,u _Catic: port--on 3a to the radiator 3b. The high-temperature side communication pipe 34b is disposed substantially in parallel withthe radiating pipes 31b and in a fixed spacing relation (preferabiv, in a spacing larger than the distance between the radiating pipes 31b, more preferably in a spacing more than twice of the spacing therebetween).

The low-temQerature-s-ide commurJ;_cation pipe 34a is communicated with the radiating-side lower coinmunicaticn 7 portion 43 of the radiator 3b and the he-;zt absorbing-side -ower -'0 communication portion 41 of the refrigerant tank 3a to re-:urn the refricerant 8 cooled and licuefied. in the radiator 3b to the refrigerant tank 3a. The low-temperature-side communication pipe 34a is disposed substantially parallel to the heat absorbing pipes 31a with a predetermined interval (preferably, in an interval larger than the distance between the heat absorbing pipes 31a, more preferabiv in an interval more than twice of the interval therebetween).

The refrigerant 8 is composed of HFC-134a (chemical formula: CH2FCF3) or water and is set in a range where the internal pressure of the tank is not so high (in the case of HFC-134a, for example, pressure less than sccres of atmospheric pressure,, that is, to be condensed bv -zihe low-tempera--ure -ure fluid.

and boiled by the high-tempera- More srecifLcally, the refrigerant is selected to!De boile,-4 at 100: C.;:e--e, the re"Lcriaerant mav be a mixture of --efrigerants havng a plura!'Ltv of comDositions or a re:ff--faerant incluaina mainiv a sinale comnosition. The refr iceran-: 8 is sealed up to the amount in which a liciuid level lowers slightly below the heat absorhing-side upper co=unication portion 42 of -he refrigerant 3a. Preferably, the amount of refrigerant may be set suc.- that a liquid level does not reaches the rad'.ating oipe 31-'- dur4nq -he operation.

L The refrigerant 8 is seale- after the heat absorbing fins 6a and the radiating fins 6b have been brazed and joined to the heat absor-'-ing C 4 Des 31a and the radiat_--g p'Lpes 31b.

The heat receivina fin 6a is disnosed between the he-=- absorbing pipes 31a, and the radiating fin 6b is disposed between the radiating pipes 31b. The heat receiving fin 6a and the radiatina fin 6b are co--rugating fins in which meta-7 (,fc- example, aluminum.) sheets (thickness: about 0.02 --o 0.5 mm) having a-suDer-'or heat transfer characteristics are alternate1v bent in a wavy shape, and are brazed to the flat outer wall surface of the radiating pipe 31b (that is, bein( joined in a fused state). The heat receivIng fins 6a are provided to facilita-ze the transfer of the heat on the high-temperazure fluid side to the re-fricerant 8 and tc improve the strength off the heat abso-rbing pipes 31a as well. The radiating f-4ns 6t are provided to facilita-te transfer oil the heat refricerant -Lc the low-temDerature fluid side and to the strenatn of the rad_atina ol'Des as well.

The 'nea;t insulat4nz material 5-C as the heat conduction supp-ress-'na means is formed of, --Fcr example, a foam--ng resin, urethane foam, and is ciisnosed between the tank 3a and the ccm_7.,.:n_4cat_-cn pipe 34a, and between the radiator 3b and the high -temperature side communication pipe 34b. The heat insulating material 50 suppresses the heat movement from the refrigerant tank 3a to the low-temDerature-s4Lde communication piDe 34a, and the heat movement from the hiah-temDeratu_re-side communication pipe 34b to the radiator 3b.

The heat insulating material 5-0 is not only discosed between the refrigerant tank 3a and the low-temperature-sie communication pipe 34a, and between the radiator 3b and the high-temperature-side communication pipe 34b but covers the outer periphery of the low-temDerature-side communication pipe 34a and the high- temperature side communication pipe 34b. This covering mav be directed to the entire outer periphery of the low-ternr)erature-side communication pipe 34a and the high temperature side communication pipe 34b or to a part (a vertical part). The heat insulating material 50 may not cover the entire outer periphery of the communication pipes 34a and 34b as shown in FIG. 6 but may be disposed between the tank 3a and the low-temperature-s-Ide communication pipe 34a, and between the radiator 3b and the high- temperature side communication pipe 34b.

In the above cooling aDparatus, the refrigeran-- tarks d-Lisposed in parallel with each other, and the radiatc_rs disDosed in parallel with each other.

-his embod-4ment T,; 7 1 be descri-ed .n operation of '"e-einafter.

The refrigerant 8 sealed into each absorbi-g ze 31a of the refrigerant tank 3a receives heat transmitted from the hLch-temDerature fluid throuch the heat receiving fin 6a so that the refriaerant is boiled and vaDorized. The re-Frgerant is exposed to the low-temperature '_"_'ua'_d and beccmes condense:! and liauefiea on the inner wall surface of the 1 __-ig:iDe 3"b of the low-temDerature rad'ato- 3b, an' -he rad'a,-- i.T condensed latent heat is transmitted to the low-tem.-erat'.:re L-Luid thrcuon the radiating -IL.in 6b. T'-,e ref-_-'cerant 8 condensed and liauefied in the radiator 31D moves alonz: -L,-e inner wall surface due to its own we-Jaht and drops onto the heat absorbina-s-ide lower communication po_rtLon 41 o--" the refr 4 aerant tank 3a. By repeating the boilina and the condensaticn and licuefacticn of the refrigerant 8, the h-ah temDerature 7 uid and the low-temperature fluid are not mixed, and the heat of the high-temperature -fluid can be moved to the low-temperature fluid efficiently.

An effect of this embodiment will be described below.

in this embodiment, as the heat conduct-4on suppressing means, there is p-rcvided the heat insulating material 50a as the refrigerant tank-side heat insulat4nq mazerial be,:ween the refrigeran-: tank 3a and the lcw-temperature-si,_Je c=,unicat_on P 4De 34a. ir this way, -it.4S possitle to Prevent the condense--; refriaeran:i which is condensed and 1-4cuef-'ed and moves down 3a thrcuah the low-tem-:)erature-side c='--nica-_on p1j)e 3.1a to rece_;_,,7e e ascend-'n- f orce - r -n i:- %4 corrLmun-Icat-on r-)ir)e 3-a.

0 Accordingly, it is possible to prevent the circulation of the refrigerant from being impeded, and the cooling apparatus can be downsized.

As the heat conduction suppressLna means, there is provided a heat insulating material 50b between the radiator and the high-temperature-side communicaticn pipe 34b as the radiator-side heat insulating material. In this wav, it is possible to prevent the ascending refrigerant which has been bc-iled and vaporized in the refrigerant tank 3a from radiat'ng - C) heat L the low-temperature radiator 3b through the communication pipe 34b and descending in the communication pine 34b.

As the heat conduction suppressing means, there is provided- a heat insulating material 50a coated on the cuter periphery of the low-temperature-side comnunication pine 34a as a high -temperature portion-side heat insulating material.

In this way, it is possible to suopress the heat conduction from the hightemperature portion,high-temperature air as high-temperature fluid) to the low-temnerature-side ccmmunication pipe 34a. As a result, it is possible to prevent the descending refrigerant which has been condensecd and liauefied in the radiator 3b from absorbina heat from the temoerature portion through the low-temperature-side communication pipe 34a so as to receive the ascending force in 2 5 the 1cw-te.mmerature-side communication nine 34a. In th-i-s wav, it- is noss-LIDle to prevent the circulation of refrigerant fro.-, D e:'_ n g i-Trineded, and the cooling apparatus can be downs-:zed.

As the heat conduction suppressing means, -.hereis Provided a heat insulating material 50b coated on the outer perip'nery of the h'an-temperature-s-'Lde communication p_pe 34b as a low-temnerature:)=-Lion-side heat insulatina mater-'al. In this wav, it is Doss-'ble to Drevent the ascend-Ing refrgerant whic'- ha-s been boiled and vapcrized in the _-efric:erant tank 3a -if _oM r a d _4 a z:J_ng heat to the low-temperature portion 'low temnerature aLr as lcw-t-emperature fluid) throuch the h _qh temperature- side communication pipe 34,b and descendrC 4n the io high-zemperaz=e-side communication pine 34b. Accordingly, it is possibie to prevent the circulation of refr_geran': from being impeded, and the coo-ling apparatus can be downsizeJ.

Since the heat insulating mater--:als 50a and 50b cover at leas-L..a part of the outer periphery of the low-temperature- side communication pipe 34a or the high- temperature-side commun --cat. ion pipe 34b, is possible to prevent the c-4rculation of' refrigerant from being impeded as c3mpare,_4 with prior art. Further, since the heat insulatina materials 50a and 50b cover the entire outer per _'phery of the 1 ow - tempera tu.-e- s -'de, communication pipe 3 4 a or the hich temnzera-=e-s_,de co,=iunication ppe 34b, it is poss41_]D]'_e to fur-,er zrevent the ci_=Ulation of re-4oerant beia e-ej, and --ne c',Dclna aD-rjaratus can be downszed.

'nce the heat insulla-:= ma-erial is made of a n c L res-n, ne-7-L insulation can be Derformed efficiently.

-.-e ref_-;_cera= --r-l-k 3 a I ncludes a plural ity c--- hea-_ absorting plpes 31a cilsposed suts-Lantlally in paralle! each other, a heat absorbing-side lower communication portion 41 disposed below the plurality of heat absorbing pipes 31a to communicate a plurality of heat absorbing pipes 31a with each other, and a heat absorbing-side upper communication portion 42 disDosed above the plurality of heat absorbing pipes 3la to communicate a plurality of heat absorbing pipes 31a with each other. The communication pipes are disposed substantial7v in parallel W 4 th the heat absorbing pipes 31a and commun4cated with the heat absorbing-side lower communication portion 41, thus downsizing the cooling apparatus.

Since the heat receiving fin 6a and the radiating fin 6b are joined in a state fused with the refrigerant tank 3a and the radiator 3b, the thermal resistance between the fins can be reduced as compared with the case where the heat receiving 'Lin 6a and the radiating fin 6b are mechanically mounted on the refrigerant tank 3a and the radiator 3b. Therefore, the entire cooling apparatus can be further downsized than the case where the heat receiving fin 6a and the radiating fin 6b are mechanically mounted on the refrigerant tank 3a and the radiator 3b.

Further, since the high-temperature fluid and 1cw temperature fluid flow opposedly with each other and a r)luralit,; of cooling apparatuses using boiling and condensfn ref--icerant are laminated in the flowing direction cf the h-'gh temDerature fluid and low-temperature fluid, the heat of the hich-temperature fluid can be radiated toward the low temz)erature fluid.

A second embodiment of the present invention will be described.

FIG. 8 is a side view in which a cooler accordinci to the second embodiment is applied to the box-shaz)ed co--ling apparatus; and FIG. 9 is a plane view as viewed from the outside of FIG. 8 (that is, as viewed from t1,.e left side on paper). FIG. 10 is a perspective view of the cooling apparatus 1 according to the second embodiment; and FIG. 11 is a cross secticnal view taken along the line XI-XI of FIG. 10.

The cooler according to this embodiment is mounted within the closed space 9 in the same manner as in the f irst embodiment shown in FIGS. 1 and 2. In the closed sz)ace 9, there are diSDOsed a heatina element (not shown), -for example, a trans-receiver for communication eauipment, and a power amplifier for actuating the trans-receiver.

As shown in FIGS. 8 and 9, the cooler is provided at 4ts upper and lower part with openings 13 and 14 communicated L with the closed sDace 9. The cooler is formed with a vent port 13 as an opening in communication with the upper part of the closed snace 9 in order to take gases of the closed space 9 4 Ln-Lo a heat transfer snace 11 on the hign-temperature side.

more sr-ec-4.-ffically, one side wall surface 9a and a partitioning wall 22 form an air passage 23 vertically extending through the cooler, an: -Ll%e upper end of the air passage 23 is opened to tl-,e unner art (above the fluid separating plate 2 within. tne closed sDace 9 as t.he vent port 13. The vent port 13 is formed a- its outle-t- Dortion with an introducina port 221 onerea; to the upper part of the closed space 9 so as to suppress the 4ntroduction of cool air from the lower part of the closed s-_ace 9 and to positively introduce hich-temperature air from the upper part of the closed space 9.

in this wav, the gas having a hich temperature, heated ]Dv the heatinc element 7, is introduced from the vent Dcrt I L - into the air passage 23 and led to the refrigerant tan,6-1 3a smoothly, and therefore the temperature _:n the closed space 9 can be maintained uniform. That is, since the gas having a hiah temperature, due to the heat generated from the hea'_-_ng element 7, moves upward within the closed space 9 by convection, in order to improve the cooling efficiency in the closed space 8, it is preferable that the vent port 13 is provided at the upper part of the closed space 9. In other words, when the vent port 13 is located lower than t-e fluid separating plate 2, a relatively low-temperature gas i-n the closed space 9 is introduced from the vent port 13 nto the air passage 23 and led to the refrigerant tank 3a, and the coc!'. ng efficiency in the closed space 9 is not sufficient.

Further, the entire cooling apparatus 1 is dispcse,_4 so as to be -inclined in a lateral direction (the left and rIght direction in FIG. 8) so that the cases passing thrcuch -,.I"e refrigera-t tank 3a and a radiator 3b within the llieat transfer scaces 11-1 and 12 on -he high and low-temperazure-sides smoo-:).1y flow from the vent ports 13 and 16 on the intake s-4--le -_cwar-_ the vents pcrts 14 and 17 on the d 4 sc-arge s4de. in this way, the chance in flow direction of the cases flow_nc -")e refrigerant tank 3a and the radiator 3b can be slackened so that the loss of the a.::_r flow in the narrow sDace can be reduced. As a result, the internal fan 15 within the closed space 9 can be downs-4--ed, and the heat-4ng amount genera'_ed by the internal fan 15 can be reduced so that the same amount of heat cenerated bv!---he hea-LJ_nQ element 7 can be increased (that _s, when the internal -fan 1-5 becomes 1arge-s-'zed to imn-rove the cool-ng performance, the hea-:i'na amount generated by the internal fan _15 increases, and as a resul-t- the heatin( amount the heat'nc element 7 cannot be increased).

The internal fan 15 as an.;;_nternal circulation -fan is made up -of an axial far., and sucks the air so tha-_ high te.mperatu--e air (high-temperature aLr as a higti-temperature fluid) _Jn-troduced into the vent port 13 zhrough the introducing port 221 is Jl_ntroduced between the heat absorbing pipes 31a of the refricerar.- tank 3a. The internal fan 15. is incl-inec; so as to be para.11el to the heat absorbing pipe 31a of the refr-cerant 'ank 3a. The 1-n-L-ernal -'an 15 may be inc1ined with respect to heat absorhing pipe 371a o-t tll-,e refrigerant --ank 3a.

The external fan 18 as an ex-zerra_' circulation fan -;s made un of an axial fan, and sucks -ie a4Lr so low a _!cw-_-e.m,:)erature -ent Dor- 16 tnrough:!-ie ntro-Juc-q c 2 2 1 is in-:roduce-d be--ween the ra-__-'atng Pipes 3_1_- of ''ne radiatcr 3)-_ 71- ex-.ern;7 "can 18 -s incl_ned with rescec-i --c -_he radia-?_-_-'nu cime 311 of the radiator 31--. on the d1scarce side of the external fan 18 is disposed a deflecting plate 181 for deflecting air from the external fan 18 upward. Air from the external fan 18 passes through the vent port 17 opened to the upper surface of the cooler by the deflecting plate 18-1 and is discharged outside.

A maintenance lid 9b for maintaJ;_ninc_ the radiator 3t is provided on the side of the radiator 3)b of the cooler shown --n FIG. 8. Since the radiator 3b introduces external air, dust or fore 4 an material contained in external air may clog between the radiating pipes 31b. However, these can be easily removed by means of the maintenance lid 9b. The maintenance lid 9t is fixed to the cooler during the cDeration and is opened during the cleaninQ.

FIG. 10 is a perspective view showing the cooling apparatus. Also in this embodiment, a plurality of cooling apparatuses using boiling and condensing refrigerant are laminated in the flowing direction of the high-temperature fluid and low-temperature fluid. The details of the cco-7-'ng apparatus are similar to that shown in FIG. 4 except that the 2 C heat insulating material 50 is not provided and w-Ji-7-1 be described partially with reference to FIG. 4.

As shown in FIGS. 4 and 10, the cooling apparatus includes a fluid separating plate 2 for separating a h_'a!- tem;Derature fluid (for example, high - t emperatu-re air) frc7. a 2 5 low-ter.Derature fluid (for example, low-temDerature air,; a refrigerant tank 3a composed of a plurality of heat atsorhing pi-es 31a disposed on the high -t emperatu re flui,_J side from the fluid seDarating plate 2; a refrigerant 8 sealed into the heat absorl:_inc pipes 31a to --eceive heat from the high-temperature fluid so as to b-e bc-iled and var-)or--Ized; a pair of low temperature- side communication pipes 34a, one of which is communic-;zted wi-:h the re-riaerant tank 3a he--metically while the other of whic" Dasses throuch the fluid senarating plate 2 and is extended to the low-temDerature fluid side; a communicazion pipe 34b; a low-tempera ture- side co=unica----'--n pipe 34a; a radiazior 3b coamun-'cated with the other of the high-temperature-side communication pipe 34b hermetically and composed of a plurality of radiating pipes 31b disposed on the low-temFerature fluid side from the fluid separating plate 2; a heat _-eceivina f-'n 6a joined -i- a fused state (for examcle, 4 in a brazed state) between the heat absorbing pipes 31a of the refricierant tank 3a; a radiat-ina fin 6b joined in a fused state (for example, in a brazed state", between the radiatina pipes 31b of the radiator 3b; and a heat insulating material 50 (for examole, urethane foam which is a foaming resin) as a heat conduction suppressIng means embedded between the re-fricerant tank 3a and the low-temcerature-side communication Pipe 34a and between the rad_'atcr 3b and the cc=unication oice 34D to su--nress the heat movement from the refr_qerant tank _qa tc the lCw-temperat,,:re-side communicatfon pipe 34a an-_4 the heat movement from the ra--4-iat-or 31--- tc -_e cc=uniCaticn ---e 34h.

The f_7-L:i,_; se-aratinc Dla:e 2 cons,_it-ates, for examcle, one wa-'.S-_-rface of -he -Icse-' --ace, an interior of whic' I's at a and _s made of metal ma!_-er_-:a_-Is,-c,-, as alum-Inum and joined integrally (for example, brazed) to the low- temDerature-side communication pipe 34a andthehigh- temperature-side communication pipe 34b. The fluid separating plate 2 is bored with an elongated insert hole through which the low-temoerature-side communication pirDe 34a and the hqh_ temnerature-side communication pipe 34b extend.

The refrigerant tank 3a includes a plurality of heat abscrbing pipes 31a disposed subs tant -Jall y in parallel with each other, a heat absorbing-side lower communication por':_ion 41 disposed below the heat absorbing pipes 31a communicated with these heat absorbing pipes 31a at the lower portions thereof, and a heat absorbing-side upper communication portion 42 disDosed above the heat absorbing pipes 31a communicated with these heat absorbing pipes 31a at the upper portions thereof. The heat absorbing pipe 31a is in -he form of a flat pipe having an oval (or an elongated rec-=.gular) cross section and is formed of a metal material (for exam:Dle, r4 or alum_'inum or copper) which is supe in heat transfer characteristics. FIG. 11 is a partial cross sectional view showina the heat absorbing pipe 31a. In --his figure, the heat receivina fin 6a is omitted. As shown, tl-e 'neat absorbing pipe 4 C 4 S 31a is a flat pipe having an oval cross sec-_'on, wh-L =ernally formed with a plurality of internal partitioning Dlates 33 over the vertical direction (eye-shaped cross sectlon,;. - 7 n this way, the pressure resistance Derformance is Lmnroved, and the heat absorbinq efficiency resulting from an enlarae.ment of a contact area with the refric:erant- is L-nnroved.

The heat absorbing pipe 31a can be easily formed by ext-ruding.

The radiator 3b includes a plurality of radiating pipes 31b disnosed substantially in parallel wit eac'- other, a radiatina-side lower communication portion 43 disposed below the radiating pipes 31b and communicated with the radiating pipes 31b at the lower portions thereof, ancl a radiat--Lng-side upper co=unication portion 44 disposed above the radJ 4 na pi7,es 31b and ccmmunicated with the -radiatinc- Dices 31t at the upper po-rtions thereof. The radiating pipe 31b is also in the form of a flat pipe having an oval (or an elongated rectangular c- oss section and is formed of a metal material (for example, aluminum or cooDer) which -J s superior in heat transfer characteris tics The radiating pipe 31b is likewise in the form of a flat pipe having an oval shape in sect-Lon similar to the heat absorbing pipe 31a shown in FIG. 11, which is internally formed with a plurality of internal- partitioning plates 313 over the ver-- -4cal direction (not showr). This br-'nc;s Lorth the effec' o f _LmDrcving the pressure resistance performance and the heat absorbina ef-ficiency resulting from. an enlaruement of a con--act area with the refr'cerant. T h e radilating pirpe 31t can be e-asilv formed '-v ex-:-usicn molding.

L e hiQh-terr)era--ure-side communlicaz:-Jon PiDe 34'C is communIcatec-4 with:he heat ah-sorbing-sia;e upper communication ccrticn -1-4, c-f the --ef---'--erant- -=.k 3a and --te radiatinc-s.:-de ur-ner cz)=----icati1cn portcn 44 of the radatcr 3b to deliver the 8 boiled and vaccr-zec in t.'"e --e-F--erant tank 3a to the faiia-= 31:- The 'ni-c:h-te.T,7)erat,,-,re-s4-cie cc=un-ca-z1- cn pipe 34b is disposed substantially parallel to the radiating pJpes 31b with a predetermined interval (preferably, inan interval larger than the distance between the radiating pipes 31h, more preferably in an interval more than twice of the interval therebetween).

The low- t emperature-s ide communication pipe 34a is cor,inunicated with the radiatinc-s;;.de lower communicat.;;_on oo--tion 43 of the radiator 3b and the heat absorbing-side 7 cwer communication Dcrt;Lon 41 of the refrigerant tank 3a to return the refrigerant 8 cooled and liquef-:Led in the radiator 3t to the refrigerant tank 3a. The low-temperature-side communication pipe 34a is disposed substantJLally parallel to the heat absorbing pipes 31a at a predetermined inter-,.ral (preferably, at an interval larger than the distance between the heat absorbing pipes 31a, more preferably at an interval more than twice of the interval therebetween).

The refrigerant 8 is formed of HFC-134a (chemiz:al ec,,:ation: CH2FCF3) or water and is set in a range wl-ere internal pressure of the tank is not so high (in case of HFC-134a, for examnle, pressure less than scores of atmcsp,-.er-:c pressureN, that is, to be condensed by the low-tempera-zure f--u-'d boLled by the high-temperature fluid. More spec4 iC a 7 _V, the refrigerant is selected to be boiled at 7ff C. Here, t'ne - 4 re r-ger-;znt may be a mixture of refrilger&nts having a piural4tv Off comz)csitfons or a refrigerant i-clud4ln-_ mainly a s--n--Ie COM'Dosition. The refrigerant 8 is sealed u= to the amount 4- whIch a 1 iau id level lowers slIghtly below the t e a t abso_rbing-slde upper communication portion 42 cf the refrigerant 3a. Preferablv, the amount of refrigerant is set such that a licuid level does not reaches the radiat'L-ng pipe 31b during the operaticn. The refr-'geran-z: 8 is sealed after the heat absorbinq fins 6a and the radiating fins 6b have been brazed and -ioned to -L-e heat absorhing pi. -pes 31a and the -a-4iatinc nices 311-,.

-he 'neat receivIng fin 6a is disposed between the 'ieat absorb-4ng pipes 331a, and the rad'L at4 -Ing fir. 6b is disposed between the radiating pipes 31b. The heat receiving f_n 6a and the radiat';_ng fin 6'_- are corrugating fins in which met-ai (for examole, aluminum) sheets (thickness: about 0.02 to 0.5 Mm) 4 which -S suDerior in heat transl"er characterist4;.cs are alternateiv bent in a wavy shaDe, and are brazed to the 'flat, outer wall surface of the radiating Dine 31b (that is, being joined in a fused stuate). The heat rece4v4na -Ins 6a are provided to facilitate the heat transfer on the high temmerature fluid sIde to the refrigerant 8 and to improve the strength of the heat absorbing pipes 31a as The radiating firs 6b are provided to facilitate heat transfer of the refricerant to tne low-temDeratu_-e fluid s';_de and to improve the strengti c:f_ the _radiat-n- pilpes as we7l.

t 4 Cp is 7n "s embcdLr.en-:, the "gh-temperature Dcr - formed w-'th a h J gn - t emperat'_7re passage 335-a t-roug"-' wh-'ch higt temnerazu_-e air as a h_4-,,11-t_--_,nperatu_-e fluid flows, and the low -orme- em. n e r a r e Dcrtion s -4 with a lcw-'remnera-:ure;DassaQe 35b throuan whLCh __ow-eir.perature a2-r as a _'ow--,em-_e_-a:ure fluid flows.

In this embodiment, as the heat conduction suppressing means, there is employed a plate-like member disposed at leas-, between the refrigerant tank 3a and the low- temperature-s ide communication pipe 34a and between the radiator 3b and the high-temperature-side communication pipe 34b.

The high-temperature-side passage 35a is ccnstructed by a fluid separating plate 2 and a high-temperature-side dividang member 5-Od formed from a plate-like member surrounding the outer periphery of the refrigerant tank 3a. The refrigerant tank 3a is disDosed in the high-temperature passage 35a, and t 4 the low-temDerature-side communica -on pipe 34a is separated from the hich-teMDerature passage 35a so as to be in a lower temperature region. That is, as shown in FIG. 12, -he low temoerature-side communication pipe 34a is disposed outside the high-temperature-side dividing member 50d'. A bracket is disposed on the whole surfa-ce of the low-temperature-side cc)mmunication pipe 34a at the upstream portion where hich temoerature air flows to prevent high- temperature air from flowing into the space where the low--emnerature-s4_de conLmunication pipe 34a is disposed.

in the same manner, the high-temperature-side passage 35b includes a --Fluid separating plate 2 and a high-temperature sicie dividing member 50c forme,_J from a plate-11"ke merr.Der 2 surrounding the outer periDherv of" the radiator 3b. The radiator 3b is disposed in the low-temDerature Dassaae 35a, and the high-temperat-ure-side communication pipe 34b i-e,:ara-- from the low-temperature passage 35b so as to be in a hicher temperature region. That is, the high-temperature-side communication P-;_Qe 3 4 b is disr)csed outside the hich temperatu,re-side dividing member 50c.

7he flange fixes the cool4ng apparatus, and functions to maintain a predet-e-1-mined space between the refrigerant:ank 31a and the lowtemz)erature-side communica-__on Pipe 34a and between the radiator 31b and the high-tempera,_,,:.re-s -4Je communication pipe 34b.

in this embodiment, as the heat conduction suppressing means, the fluid separating plate 2 and the h igt temperature- side dividing member 50d for dividing the high temperature passage 35a are provided between the low termperature-side communication pipe 34a and the radiating pipe 31a, and the low-temr)erature-side communication piDe 34a is se,)arated bv the hich-temperature-side divLaiing member 50d so as to be in a region where the temDerature is lower than that in the hiah-temDerat-ure passage 35a. Tn tlns wav, the 'neaa, conduction -from the high -temperature passage to the __Cw_ temDerature-side conmunication pipe 34a can be suppressed. As a result, it.4S poss_hle to prevenz: the descendina refrige-ran-::

which has been condensed and licue-fied in the radiatcr 3b from atsorblnc he-at from tl7e In igii-i- t emaera ture passage through the lCw-tem::)er_=,tu,re-side commulnica-Lon ripe 34a and re-evna t-e ascendinc force the low-temr)eratare-side com:7.-_,nica-r__cn zize 311 4 "s possit-e -o iDrevent -t-,ie crculaton cf a.:'-_s wa-,,, _L - - - - L __ - refrigerant from being ir.pede,_-, and the cool-ng apparatus can be downsized. Further, as the heat conduction suppressing means, the fluid separating plate 2 and the high-temperature side dividing member 50c for dividing the high-temperature passage 35b are provided between the higt-temperature-side communication pipe 34b and the heat absorbing pipe 31b, and the hich-temDerature-side communication pipe 34b is separated):y the high-temperature-side dividing member 50c so as to be in a recion where the temperature is higher than that in the low temperature passage 35a. In this way, the heat conducticn from the low- tempera ture- side communication pipe 34a to the low temperature passage 35b can be suppressed. As a result, it is possible to prevent the ascending refrigerant which has been boiled and vaoorized in the refrigerant tank 3a from radiating heat to- the low-temperature passage through the high temperature-side communication pipe 34b and descending in the high-temperature-side communication pipe 34b. In this wav, it is possible to prevent the circulat-ion of refrigerant from L being impeded, and the cooling apparatus can be downsized.

Further, in the multi-stage cooling apparatus shown in FIG. 10, each lowtemperature-side communication pipe 341a is senarated from the high-temperature passage and each '1_'ch _emDerature-side communication pipe 34b is separated from the lcw-temDerature passage, and therefore the temnerature efficiency when the fluid flows can be improved.

The cooling apparatus according to this embodiment can te divided into a portion where a 4. _ can be blown (a -F4n portion) and po--tions where air cannot be blown (the low temperature-side communication pipe 3 4 a the high temDerature-side communication pipe 34b). when air is simply blown bv a 'fa:- -Incz shown) to the multi-stace cooling ar-naratus as in this embodi-ment, the air is contracted when flowing into the fLn -ortion, and -'s expanded after passing through the fin L - e - - - portion, and as a _resuIt pressure loss may occur. However, in this emDodLment, tne "lian-tem;Derature passace 35a is bv the fluid secarat--na Plate 2 and the h1gt-t_-emr_erat,,:re-s_'de dividin.- member 51d, and the low-temnerature oassace 35b is divided by the flu_d separat4;_ng plate 2 and the hilghtemr)erat,,:re-side dividino member 50c. Therefore, air flowing through the passages 35a and 35h flows linearly so that thle pressure loss can be reduced. In this way, the consumed power of the fan and the noise of the air flow can be reduced.

Further, since the cross section where the air is blown is restrIcted as compared with the case of non-division, the flow amount of the 'Lin portion can be increased.

S_nce the hlah-te.mr)erature-side commu,-icatl'on Dipe 34h 4s disposed substanzial-ly parallel to the heat absorling pipe 4 -ervai (preferably, an inter-:a-, -araer 31b at a:)redete,_Lned -ir.L than the -_is-_ance between the heat atsorblng pilpes 31b, -more D r e f e r a-'- I v a n _ r -_ e f a s tW4 ce as t'-e 4n-erval or more), it is :)cssible tc the ascendi-g re-'riz:erant whicn has been toilec and vaccr_4zed 41 n the --ef r-'gerant tank 3a _from rad_at n-1 -) = _, t- 'n = - the hich- --- tc low-temnerature radiator 31D tnro'_,q'n temnerature-Sla4e _0=-n4cr--on pipe "t and a4escendng in the h _4 a h - t e m: e r a t u r e - s L d c 3 r _4 c a o n r-;_rDe 3 4 iD The Ow- temperature- side communication pipe 34a is communicated with the radiating-side lower communication portion 43 of the radiator 3b and the beat absorbing-side lower communication Dortion 41 of the refrigerant tank 3a to return the refrigerant 8 cooled and liquefied by the radiator 3b to the refrigerant tank 3a. Further, since the low-tem.Derature-side communication pipe 34a is disposed substantially parallel to the radiating pipe 31a at a predetermined interval (preferably, an interval larger than the distance between the radiating pipes 31a, more preferably an interval as twice as the interval or more), it is possible to prevent the descending refrigerant which has been condensed and liquefied in the radiator 3b from absorbing heat from the high-temperature refrigerant tank 3a through the low temperature- side communication pipe 34a and receiving the ascending force in the low-temperature-side communication pipe 34a.

In the aforementioned first and second embodiments, in the refrigerant tank 3a, heat can be received bv the plural--'--y of heat absorbing pipes 31a, and therefore the heat absorbing efficiency is improved. The refrigerants boiled and vaporized by absorbing heat are collected at the heat absorbing-side upzer communA_cation portion 42, and the refr--:-aerant delivered to the radiator 3b by -the high-temperature-side conmunication pipe 31b. Therefore, the num-'-er of Dipes --for communicating between the radiator 3b, and the --refrigerant --ank 3a can be reduced, and the fluird seDarat_na olate 2 can be easilv machined. Further, in the radiator 3b, heat _Js radia_--_6 by the plurality of heat absorbing pipes 31b, and therefore the radiatina efficiency is improved. The refrigerants condensed and licuefied are collected at the radiating-side lower communication portion 43, and the refrigerant is delivered to the refrigerant tank 3a by the low-temperature-s--lde communication P41-De 34a. Therefore, the number of pizes for communic-=-LinQ between the radiator 3b and the refrigerant tank 3a can be reduced, and the fluid separating plate 2 can be easily machined.

The high- temperature-side dividing member 50d need not be constituted by the plate-like member disposed between the flange and the higt-temperature-side passage 34a, as shown in FIG. 12, but may be of an interpolation flange 50e held between the flanges, as shown in FIG. 13. Similarly, the hich temDerature-side dividing member 50c need not be Constituted by the plate-like member disposed between the flange and the high temperature-side passage 34b but may be of an interpolation flange 50e held between the flanges. In this case, air is blown more smoothlv.

in FIGS. 12 and 13, since the bracket is disposed at.

the urDstream side of' the reQion where air is blown, higl-.

-emDerature air does not collide with the low-temDerature-side communication pipe 34a, and the low-temDerature-side cc=un-'c__-=-_on PiDe 34a can be prevente"A' from being heatela by --he hi-h-temzerature aJ_r. However, even in the case of the or=slte directlon of the ailr f7 owing d'recton shown 71G.

12 (t.-ie bracket is disposed at the downstream side), air stagnates in a region surrounded by the cabinet side plate, the bracket and the high-temperature-side dividing member 50d, and substantially the high -temperature air does not collide with the low-temperature-side communication pipe 34a. In this way, the low-temDerature-side communication pipe 34a can be also r)revented from being heated by the high-temperature air. Simllarly, even in the case of the opposite direction of the air flowina direction shown in FIG. 13 (the bracket is disposed at the downstream side), air stagnates in a region surrounded bv the cabinet S4 de plate, the bracket and the interpolation bracket 50e, and substantially the high-temperature air does not collide with the lowtemperature-side communication pipe 3 4 a. In this wav, the lowtemperature-side communication pipe 34a can be also prevented from being heated by the hightemperature air.

A third embodiment of the present invention will be described.

FIG. 14 is a side view showing an entire structure of a cooling apparatus using boiling and condensing refrigerant according to a third embodiment of the present invention.

The cooling apparatus 1 is for cooling an IGBT module 2 (heat generating element) which constitutes an inverter circuit of an electric vehicle or a general electric power control equipment or the like. The cooling apparatus 1 _ncludes a refrigerant tank 3 containina a fluorocarbon-type P'-aerant, a radiator 4 for cooling and liquefying vaporized refrigerant which has been boiled and vaporized in the -49- refrigerant tank 3, and cooling fan 5 for blowing air to the radiator 4.

As shown in FIG. 14, the IGBT module 2 has a radiat'na plate 2a for radiating heat generated from a semiconductor element (not shown) incorporated in the module. The 7GBT module 2 is fixed; to the refrigerant tank 3 by tightening plural bolts 6 while the radiating plate 2a is in a state as to be close-1v contacted with an outer wall surface of the refriaerant tank 3. In this embodLnent, six IGBT modules 2 (two in the transverse direction of the tank 3 and in three stages vertically) are mounted on one outer wall surface of the refrigerant tank 3.

The refrigerant tank 3 includes an extrusion member 7 formed by extruding from an aluminum block for example and a pair of end caps 8 and 9 for closing both upper and lower end openings of the extrusion member 7.

The extrusion member 7 is of a vertically long and flat shape having a small thickness relative to the width. As shown in FIGS. 1_5 and 16 (a cross sectional view taken along the 1-4ne XVI-XVTL of FIG. 15), a vapor passage 10, a condensed; liquid 4 passace 11, a heat _4nsulatJnq passage 12 and an -1noperative passage 13 are formed lonai-:udinally (vertically in F7G. ',r-) r 4 throuch tne inte -or of the extrusion mem-er 7 while remaining support =_3 portions 14, 15, 16 ana 117 between adacent C:

passages.

'-ie vaDor passaces and 101D are regions where vaporize-_ -re-f-rigerant which has been boiled and vaporized by the heat from the IGBT modules 2 ascends within the refrLQerant tank 3. Two vapor passages are formed side by sidein correspondence to the mounted positions of the IGBT modules 2.

The condensed liquid passage 11 is a region into which a condensed licuid which has been cooled and liquefied in the radiator 4 flows and is formed on one side in the transverse direction. The heat insulating passage 12 functions to decrease the amount of heat transferred from the vapor passage side to the condensed liquid passage 11 side and is fcr-ned between the vapor passages 10 and the condensed liquid passage 11. The inoperative passage 13 is for taking balance w4Lth respect to the condensed liquid passage 11 while the extrusion member 7 is being extruded, and is formed on the side opposite to the condensed liquid passage 11 in the transverse direction of the refrigerant tank 3. Thus, the inoperative passage 13 is not used as the condensed liquid passage 11.

t 4 Each of a support wall portJLon 14 for partL _Lcning between the two vapor passages 10a and 10b, a support wall portion 15 for partitioning between one vapor passage 10a and the heat insulating passage 12, and a support wall portion 16 for partJ..tioning between the other vapor passage 10h and the inoperative passace 13, is formed with plural screw holes 1-8 'nto which bolts 6 for mounting the IGBT modules 2 are threaded-J, as shown in FIG. 15.

In one outer wall (the wall on the side where the IGBT modules 2 are mounted in this embodiment, of the extrl.:sion member 7 and in an area (the area indicate-_ with a broken -7-ine B) to which the radiator 4 is connected through a connecting plate 19, as shown in FIG. 14, there are formed a refrigerant vapor outlet port 20 and a condensed liquid inlet port 21. The outlet port 20 is open above the inoperative passage 13. Since the upper portions of the support wall portions 15, 14 and 16 are removed by post-machining such as milling for example, the outlet port 20 is in communication with the vaocr passages 10 and the heat insulating passage 12. There is a sliont difference in he-Lqht between the inlet port 21 and the cutlet port 20 so that the lower end of the inlet Dort 21 is a lit-k-le lower than the lower end of the outlet port 20.

The end caos 8 and 9 covers both open ends of the extrusion member 7 and intearally connected thereto by solder--ng. In this case, the top end caD 8 is attached while closing the upper end opening of the extrusion member 7, whereas the bottom end cap 9 is attached to the lower end f 4 opening of the extrusion member while de -ning a communication path 22 between the lower end of the extrusion member 7 and the bottom end cap to provide communication among the vapor passages 10, condensed liquid passage 11, heat insulating passage 12 and inoperative passage 13.

The radiatcr 4 is a so-called drawn-cur) type heat exchanger and, as shown in FIG. 4, Jt is constiz-_eci by laminat-4.-a a plural_"iy of hcllow radiat_'ng tubes 23 of the sa-ne shane and is attached to the refrlgerant tank 3 throuc, the ccnnect4;_na plate 19.

As shown in FIG. 17 (a cross sectional view taken along the line XVII-XVII of FIG. 14), the radiating tubes 23 each include two pressed plates 24 of a generally rectangular shape in plan. outer peripheral edges of the pressed plates 24 are jointed together to form a hollow body. The two pressed plates 24 are formed in the same shape by pressing a metallic material (e.g. aluminum) superior in heat conductivity, with communication openings being formed in both ends of eacl-I mold plate 24. The whole of the central portion of each rad-ating tube 23 constitutes a flat refrigerant passage 26, into which are inserted inner fins 27 obtained by corrugating a thin aluminum olate. At both ends of the refrigerant passage 26 are provided communicating portions 28 having the communication openings 25. The communicating portions 28 are connected to the communicating portions 28 of other radiating tubes 23 through the communication openings 25, thereby constituting a tank portion of the radiator 4 as a whole.

As shown in FIG. 17, the radiating tubes 23 are laminated so that the respective communicating portions 28 face each other. mutual communication of the radiating tubes 23 is ensured through the communication openings 25 formed in the communicating portions 28, with radiating fins 29 being posed between adjacent radiating tubes 23 which are lin a laminated state. Provided, however, that the outside pressed plate 24 of the radiating tube 23 located at the outer:-nost position does not have the communication openings 25.

Alternatively, there may be used a pressed plate 24 having the communicat4= onenings 25, but in th.'s case the communica----cn openings 25 are closed hermetically with an end plate (not shown) or the like -from the outside.

The connecting plate 19 is connected hermetically to an outer wall surface of the extrusion member 7 so as to cover the inlet port 21 and the outlet port 20 both formed in the ex trusion member. One communication chamber 30 communicating with the outlet port 20 and the other communication chamber 31 communicating with the inlet port 21 are formed between the connecting plate 19 and the outer wall surface of the extrusion member 7. Both communication chamber 30 and 31 are in communication with each other through the refrigerant passage 26 in which the inner fins 27 are disposed. The connecting Dlate 19 has the same co=un-ication openings as those formed in the pressed plates 24, through which there is provided communication between the communication chambers 30, 31 and the radiating tubes 23.

As shown in FIG. 14, the cooling fan 5 is an axial flow fan, which is disposed above the radiator 4, with a fan shroud 5a being fixed with bolts (not shown) to a side face of the radiator 4.

An operation cf th_s embodiment will be described below.

Refriaerant in the vapor passages 10 with IGBT modules 2 attached to the outer wall sur-faces of the same passages boils and vai:)orizes wh';_Ie receiving heat from the!GBT modules 2. The resulting air bubbles rise within the vapor passages 4nly 10, pass through the cutIet port 20 and flow ma.L into one communication chamber 30. Then, the air bubbles flow from the one communication chamber 30 into one tank portion (the right-hand communicating portions 28 in FIG. 17 of the radiator 4, and are distributed to the refrigerant passages 26 formed in the radiating tubes 23. The vaporized refrigerant flowing through each refrigerant passage 26 condenses on the inner wall surface of the refrigerant passage and the surfaces of the inner fins 27, which are maintained at a low temDerature by receiving air blown from the cooling fan 51, to radiate a latent heat of condensation. The resulting droplets flow along the bottom of each refrigerant passage 26 and into the other tank portion (the left-hand communicat-ing portions 28 in FIG.

17) of the radiator 4. The droplets further flow out of the other tank portion into the other communication chamber 31 and stay mainly therein. The condensed licuid in the communica-Lion chamber 31 then flows into the condensed liquid passage 11 through the inlet port 21 which is open in a lower position than the outlet port 20, then flows down through the condensed liquid passage 11 and is returned again to the vapor passage 10 through the communication path 22 formed inside the end cap 9.

on the other hand, the latent heat of condensation radiated at the time of condensation of the vaporized refrigerant is transferred from the wall surfaces of the refrigerant passages 26 to --ne radiatina fins 29 and is -radiat--ed to the blown air Dassina between adjacent radiating tubes 23.

L An effect of this embodiment will be described.

AccordinQ to the coolinc anDaratus 1 O.L +.-his embodiment, in the heat transfer path through which the heat generated from the IGBT modules 2 is transferred through the extrusion member 7 up to the refrigerant in the condensed liquid passage 11, the heat insulating passage 12 formed between one vapor passage 10a and the condensed liquid passage 11 functions as a thermal resistance. Further, a large proportion of the heat moving through the said heat transfer path is absorbed by the refrigerant in the heat insulating passage 12 and contributes to the rise in temperature of the ref-ricerant in the passage 12. As a result, the amount of heat passing through the aforementioned heat transfer path and transferred from the vapor passage 10 side to the condensed liquid passage 11 side is decreased and thus it is possible to prevent the refrigerant in the condensed liquid passage 11 from boiling. Consequentlv, the refrigerant circulates between the re-Iffriaerant tank 3 and the radiator 4 favorably, and the deterioration of the radiating performance due to the boiling of the refriaerant in the condensed liquid passage 11 can be prevented.

A fourth embodiment of the present invention will be described.

Ct4 FIG. 18 is a partia7L cross se -onal view of a efrigerant tank 3, showing a neat transfer decreasing Structure.

in this embodiment, as --he heat transfer decreas-Lng structure of the refriuerant tank 3, a suDr)crt wall portion 32 for part it icn 41 nabetween the condensed liquid passage 11 and one vapor passage 10a is provided with a constricted part 32a having a reduced cross sectional area. In this case, because the amount of heat transferred from the vapor passage 10 side to the condensed liquid passage 11 decreases, it is possible to prevent the refrigerant in the condensed liquid passage 11 -from boiling.

A fifth embodiment of the present invention will be described.

FIG. 19 is a partial cross sectional view of a refrigerant tank 3, showing a heat transfer decreasing structure.

In this embodiment, as the heat transfer decreasing structure of the refrigerant tank 3, air-cooling fins 32h are for-med outside a support wall portion 32 which spaces between the condensed liquid passage 11 and one vapor passage -10a.

According to this embodiment, part of the heat transferred through the support wall portion 32 is release-_J to the atmosDhere through the air-cooling fins 32b, so that -he amount of heat transferred from the vapor passage 10 sLde to 2 C) the condensed liquid pasage 11 decreases. Therefore, the re-rr4aerant in the condensed liquid passace 1-1 can he preven':-_,d Lrcm boilinc.

A sixth embodiment of the present invention w--,----- be r'escribed.

FIG. 20 is a partial cross sectional v_4e_,.%T 0: a -ergerant -ank 3, showina a heat transfer L decre=s-nc st'ructure.

In this embodiment, inner fins 12a are projected on the inside of the heat insulating passage 12. According to this embodiment, the radiation area in the heat insulating passage 12 increases by the inner fins 12a, so that the radiating performance by boiling the refrigerant in the heat insulating passage 12 is improved and hence the amount of heat transferred from the vapor passage 10 side to the condensed liquid passage 11 side decreases, and therefore, the refrigerant in the condensed liquid passage 11 can be prevented from boiling.

A seventh embodiment of the present invention will be described.

FIG. 21 is a partial cross sectional view of a -e-Fr4gerant tank 3, showing a heat transfer decreasing structure.

In this embodiment, the heat insulating passage 12 has an inner wall surface 12b of a concavo-convex shane. According to this embodiment, as compared with the case where the inner wall surface of the heat insulating passage 12 is a plane surface, the boiling of refrigerant in the heat insulating passage 12 is accelerated, so that the amount of heat transferred from the vapor passage 10 side to the condensed liquid passage 11 side becomes smaller, and therefore the refricerant in the condensed licuid passage 11 can be prevented from boiling.

An eighth embodimen-- of the present invention will be described.

FIG. 22 is a vertical sectional view of a refrigerant tank 3.

In this embodiment, the upper portion of 'Zheheat insulating passage 12 is brought into communication with the condensed liquid passage 11. Also in this case the heat 4 nsulating passage 12 functions as a thermal resistance and part of the heat transferred throuch the extrusion member 7 is absorbed bv the refrigerant in the passace 12, so that the amount of heat transferred from the vazor passage 10 side to the condensed liquid passage 11 side is decreased to an extent sufficient to prevent the refrigerant in the condensed liquid passage 11 from boiling. In proportion to an increase in internal pressure of the boiling portion due to the air bubbles, there occurs a difference in licuid level between the boiling portion and the condensed liquid passage 11 during the operation oil the cooling apparatus so that the liquid leveI of the condensed liquid passage 11 becomes higher. As a result of com.munica-t.ing between the condensed liquid passage 11 and the 4 heat insulating passage 12, the -quid leve! in the passage 1-2 becomes higher than in communication with the boiling portion, so that the radiation area in the heat insulating passage 12 increases and the cooling effect is improved, and the _,::,4'.

__=aerant in the condensed liquid passage 111, car, be prevented A ninth embodiment of the present invention will be 2 5 described.

F7 q t 4 J- 23 to 25 are vertical cross sec -onal views of re-frIgerant tanks 3.

In this embodiment, a plurality (two in each of FIGS.

23 to 25) of heat insulating passages 12 are formed. FIG. 23 shows an example where the upper portions of two heat insulating passages 12 are in communication with the vapor passages 10. FIG. 24 shows an example where the upper portion of one heat insulating passage 12a is in communication with the vapor passages 10 and the upper portion of the other heat insulating passage 12h communicates with the condensed liquid passage 11. FIG. 25 shows an examz)le in which the upper portions of two heat insulating passages 12 are in communication with the condensed liquid passage 11. In each of t 4 these examiDles, since plural heat insula _nc passages 12 are provided, the amount of heat transferred from the vapor passage side to the condensed liquid passage 1.1 side becomes smaller 1-5 and hence the refrigerant in the condensed liquid passage 11 can be further prevenzed from boiling.

A tenth embodiment of the present invention will be described with reference to FIGS. 26 to 31.

FIG. 26A is a diagram showing a schematic structure of a cooling unit using boiling and condensing refrigerant, FIG.

26B is a diagram showing a heat exchanger including cooling units arranged in nlural staues, and FIG. 27 is a diagram showing an entire structure of an electronic apparatus.

The electronic aznaratus fcr example, s an anDaratus installed in a radio base station of a z)or-.ab--,-- radic --eler)hone such as a cordless -.elezhcne or a car telephone. --he S 4 - electronic apparatus I includes a hou _nC 13 for housing therein electronic parts 11 and 12 in a hermetically sealed state, and a cooling apparatus (cooler) 14 mounted within the ho,asinc 13 to cool the electronic parts 11 and 12.

The electronic part 11 is a heat generating element win.lich oerforms a predetermined operar--,on when an electric current is supplied thereto and which cenerates heat (--For examole, a semiconductor sw-itchinQ element const4ltuting a Itigh-frecTuencv switching circuit incorDorated in a -zrans-receiver). The electronic Dart 1-2 is a heat Qeneratina element which also performs a predetermined operation when an electric current is supplied thereto and which generates heat f"Lor example, a semiconductor amplifier element such as a power transistor incorporated in a power amplifier).

The housing 13, which is for sealinq the interior from -'5 the exterior hermetically, defines a sealed space 15 in the interior. In order to prevent deterioration in performance cff the electronic Qarts 11 and 12 by deposition thereon of foreign material such as dust and moisture, tne sealed space 15 is hermetical1v sealed completely from the exterior by means of, -for example, a fluid separating plate used in a cooling aDnaratus 14 which will be described later.

Bv means of both a fluid sezarat.:Lna plate used in --'ne Cocling apparatus _14 and a casing of the COC7 4 na apparatus 14, :he sealed snace 15 is Partitioned _J T,. _-c an electronic part 2:z accommodat_'nc sDace 16 for accom-mc-dazinc --',-e electronic Darts and 12 and a high-temr)erature-si"- he7-t -ranser siDace 7 serving as a passage inside a closed; bociv. I n o to S4 minimize the deDth I-ze of the cooling apparatus 14, the -flow path area of the high- temperature- side heat transfer space 17 is narrow on the upwind side, while the flow path area of the same snace on the downwind side is wider. Further, the housing 13 defines a low-te.T.Derature-side heat transfer space 16 as a passage outside the closed body, which is hermetically sealed from the h-Ightemneratu--e-side heat transfer space 17 by the fluid ser)aratinQ Dlate.

The cooling apparatus 14 includes a casing 20 integral with the housing 13; two upper centrifugal blowers 21 11-or generating a flow of a low-temperature air (external fluid, low-temnerature-fluid); two lower centrifugal blowers 22 for L generating a flow of a 'nigh-temperature air (internal fluid, high-temperature fluid); an electric heater 23 for maintaininq the a4- temperatu.re in the sealed space 15 at a level not lower than a lower-l-imit temperature (e.g., 0:); a controller 24 for controlling the supply of electricity for the electric devices used in the cooling apparatus 14; and a heat exchanger 25 for maintaining the air temperature in the sealed space 15 at a level not hiaher than an unr)er-limit temperature (e.g., 65::

The casing 20 includes an outer wall plate 26 disposed on the cutermost side of electronic apparatus 1 and a -ear -L -s4de partition p-late 2 7 which surrounds the hiah ter wall r)-"a±-e temperature- s icie heat trans'L":er space 71 The ouL n 7 26 and the rear-side par-_i--_-'cn --a-Le 27 are fixed to '_he ncus i na 3 bv!D-onding, e.g., snot welding, or by us]_nq fasteninc means such as screws or!Dc!!--- s The two upper centrifugal blowers 21 are each provided with a centrifugal fan 31 for generating a flow of air in the low temmerature-side heat transfer space 1-8, an electric motor 2 'or rotating the centrifucal fan 31, and a scroll casing 33 wh4.ch receives therein the centr-ifuQal fan 31 rotatably.

The two lower centrifugal blowers 22 are eac, provided with a centrifugal fan 34 for generating a flow of air in the hich tem=erature-side heat transfer space 1-1, an eleczric motor for rotating the centrifugal fan 34, and a scroll casina 36 which receives therein the centrifugal fan 34 rotatably.

The electric heater 23 is for heating air flowing through the high-temperature-side heat transfer space 17 so that the internal temr)erature of the sealed sz)ace 15 is maintained not lower than the lower-limit. temperature (e.g., 0:) because the electric parts (e.q., semiconductor elements) 11 and 12 deteriorated in performance thereof when the internal temoerature of the sealed sDace 15 Is lower than the lower-!Lmit temperature. The electrLc heater 23 used in --his embodiment has a calorific value of, for example, 1.2 kw.

The controller 24 is for controllina electric dev-ces such as the electric motors 32 cIL the two ucDer centrifucal -Icwers 21, the elec-.---4c motors 35 o--" the two lower centrifucal Lowers 22 and the electric heater 23 in accordance with the 4n,ernal temperature of the seale-_J space 15 detected hy a temnerature sensor 9 constituted bv a temnerat-ure-sens __ --ve element such as a thermistor.

,hen the ';_nternal temDerar---,re oLc:he seazled scace L5 is not lower thar. the lower-li-mit temperature (e.g., 0:' the controller 24 controls such that the two upper centr13tugal blowers 2-1 and the two lower centrifugal blowers 22 are oper ated in H-4 (strong air volume) or Lo (low air volume) mode and the electric heater 23 is turned OFF. On the other hand, when the internal temPerature of the sealed space 155 is lower than the lower-limLz temperature (e.g., 0: the controller 24 control s such that the electric motors -_- 2 of the two upper cen trifugall blowers 21 are turned OFF, the electric motors 35 of the two lower centrifugal blowers 22 are operated in H_J (high air volume) or Lo (low air volume) mode, and the electric heater 23 is turned ON.

Next, the heat exchanger 25, which is provided with coolina units, willbe described in det-aLl with reference to FIGS. 26 to 31. FIG. 26 is a diagram showing a structure of a C 4 cooling unit spe -f-4cally, and FIGS. 29 and 30 are diagrams each showing a fluid separating plate which div.-L"Ies the cooling unit into two oortions.

The heat exc'-ancer 25 includes a fluid senaratina z7ate 2 and cooling units 3 mounted in plural (twc) s--aces to the fluid sei-aratina olate 2 while extendin- throuc'-, -he plate 2.

The flu-'"' senarat_ng plat-e- 2 sepa-rates a hizh-temDerature air wh -'ch is the interna I a Ir ( so-called ins lide a i r ', c --"ng throuah the in-ier_Jor of the hous'Lng 13 and a low-tempera-z:ure air wtic'- is t,e exter-al air 1so-c-alled o1.:tsi1z4e- air) circu- ca 1 7 _'7 -at4na -ihe nousna 4:-om each otner n a herme-:J - sealed state.

The fluid separating plate 2 constitutes a wall surface (a part) of the housing 13 including both a wall surface of the sealed sDace 15, an interior of which becomes high in te.T.Derature, and a wall surface of the low temDerature-side heat transfer sDace 18, an interior of which becomes low in temDerature. For example, the fluir-1 separating plate 2 is constituted by a thin plate of a meta_!_,_c material superior in heat conductivity such as aluminum. The fluid ser)aratinq Diate 2 is soldered together with the cooling units 3 and the casing 20 so as to provide a hermetic par- it 4 on - between the sealed space 15 including the high temperature- s -Lde heat transfer sDace 17 and the exterior includina the low temperature-s'de L heat transfer space 18.

As shown in FIG. 29, the fluid separating plate 2 has a plurality of elongated, rectangular or oblong through holes 38 (for example, 1.7 mm wide,.16.0 mLm long) for passing there through of cooling tubes of each cooling unit which will be described later. The through holes 38 are formed at precie-ter mined intervals. The fluid separating plate 2 may be a split plate, as shown in FIG. 30.

The cooling units 3 are mounted in plural (two) stages inclinedlv bv a Dredetermined angle within t:e casing 20. 7he coollina units 3 are multiflow pass type heat exchanger un-'ts e----c'- includina a plurality of cooling tubes 4 w_'th a fluorocarbon- or freon-type refrigeranz sealed therein, a pair Of co7mmunication pines 5 for communic-ating amc,nq the cool'na tubes 4, anc a plurality of heat transfer _f3ins 6 attac-ec-4 to the exterior of each cooling tube 4. To both sides of each cooling unit 3 are connected side plates 37 which function to secure the cooling unit 3 to the fluid separating plate 2 and the casinc 20 by means of fastening means and which also function to reinforce the plural cooling tubes 4 and Diu--a! heat t_-ansfer f--'ns 6. The coolinq un-4ts 3 are disoosea in Dlural stages (for example, two stages) -in --flowing directions of.both h.'Lah-temperature air and low-temperature air.

The plural cooling t-_,bes 4 are each formed J1.n the shape of a flat tube (for example, 1.7 mm wide, 16.0,nm long) having an elongated, rectangular or oblong cross sectional shape, using a metallic material superior in heat conductivity such as, for example, aluminum or copper. The cooling tubes 4 are dispcsed,so as to extend through the through holes 38 formed in the fluid seDaratina plate 2. one side (the lower side in FIG.

28) of each cooling unit 3 including the coollng tubes 4, which side is the hich-temperature air side with resiDect to the fluid 4 S -z tank separating late 2 constituted as a liquid refrigeran (boiling portion) 7, while the other side (the upper side in FIG. 28), which side is the low-te.mDerature air side with resDect to the flu-4d separating plate 2, is constituted as a vanorize-_ fefrLaerant tank (condensing port-Jon) 8. in this em_-odiment, the hoilina oortion 7 and the condensna por-:::_c.n 8 are 360 = wide 1,transverse size), 1 30 mm 1-iigh and 16 Tn thLck 7,-Ie Co7ununication p4pes 5 are cons t t,,:-ed '-v a -Lemperature-side tank 41 connected to the lower ends of the Dlural cocling tutes 4 b o i _1 _4 n g por-i ion 7 an d a -low tempera tu-re-side tank 42 connected to the upper ends of the plural cooling tubes 4, thus providing communication among the tubes 4. The high and low temperature- s JLde tanks 41, 42 are each composed of a core plate disposed on the side of the cooling tubes 4 and a generally inverted U-shaped tank plate affixed to the core plate. A single refrigerant sealing port (not shown) for sealing a refrigerant into the cooling unit 3 is formed in either the high temperature-s--ii-de tank 41 or the low temperature-side tank 42. The refrigerant is sealed into each cooling tube 4 of the cooling unit 3 up to a height where the liQuid level is substantially flush with the fluid separating plate, that is, up to the top of the boiling portion The sealing of the refrigerant is perl"'ormed after the heat transfer, fins 6 have been soldered to the cooling tubes 4. The high temperature-side tank 41 may be omitted.

The heat transfer fins 6 are constituted bv heat receiving fins 6a interposed between adjacent cooling tubes 4 on the high temperature side (boiling portion 7) of the coolna unit 3 and heat radiating fins 6b interposed between adjacent coolina tubes 4 on the low' temperature side (condensing po_rtion 8) of the cooling unit 3. For examDle, the heat transfer fi-s 6 are corruaated -fins (a fin pitch of say 3.75 mm) formed Ln a wavy shape by alternately pressing and bending a thin plate (a 4 ckness of, for example, 0.02 to 0.50 n,-n) of a metallic material suoerior in heat conductivity, e.c., aluminum. The .,.ns 6 are soldered to flat outer wall surfaces of the cool_ng tulDes 4. Thus, the outer wall surfaces o-L' the tubes 4 and the heat transfer fins 6 are fused together.

In the heat exchanger 25, as shown in FIGS. 26A, 263, and 2 7, the cooling units 3 are disposed in plural stages in flowing directions c f both high-temperature air and low-temoeratu-e air in such a manner that the high- temperature air (clear. air in the housinc 13) circulating in the high tempera ture- side heat transfer space 17 of the sealed space 15 and the low-temperatu-re air (foul, air in the housing 13) circula-_-inc in the low temperature-silde space 18 flow as counter flows.

In the heat exchanger 25 including plural stages of cooling units 3, the richt-hand side in the figures of the lower end portion (boiling portion 7) of the cooling tubes 4 in the cooling unit of the second stage serves as an inlet of the high-temperature air, while the left-hand side in the figures of the lower end portion (boiling porticn 7) of the cooling tubes 4 in the coolina unit 3 of the first stage serves as an outlet of the hiQh-temoerature air. Further, the left-hand S 4 side in the figures of the upper end;Do---L-ion (conden _Lng portion 8) of the cooling tubes 4 in the cooling unit of the first stage serves as an inlet of thelow-temperatlure air, while t",e _-1ghz-11iand side in the 'Jgures of the upper end port'-on condensina portion 8) cf the cccling tubes 4 in the cocling 3 of the second stage serves as an cutlet of t-;e lcw-temperature air.

170W, wi":ih reference to FIG-S. 26A, 26B, and 27, -1- X I L- - following will be lhriefll-,, described a-, or)eraztion of the cocl_na apparatus 14 equipped with the heat exchanger 25 wherein the cooling unit 3 of this embodiment is disposed in plural stages so that the h ich- temperature air and the low-temperature air flow as counter flows.

when the internal temperature of the sealed space 153 in the housing 13 is not lower than the lower-1-imit tempera-Lure (e.g., 0 Z:), the supply of electric power to the electric motors 32 of the two upper centrifugal blowers 21 and to the electric motors 35 of the two lower centrifugal blowers 22 is started, so that the centrifugal fans 31 and 34 start to operate. As a result, a flow of a high-temperature air (clean inside air not containing any foreign material such as dust or moisture; internal fluid) circulates within the sealed space 15 in the housing 13. Also, outside the housing 13, a flow of a low-temperature air (outside air containing a foreign material such as dust or moisture; external fluid) circulates within the low temDerature-side heat transfer sDace 18.

The refrigerant sealed in the cooling tubes 4 of each of the cooling units mounted in plural stages through the fluid separating plate 2 of the' housing 13 receives heat transferred from the high-temperature air throuch the heat receiving fins 6 and then is boiled and vaporized, as shown in 7 TG. 26A. The vaporized refrigerant is condensed on the inner wall surfaces of the condensing portion 8 located on the -apper end s_J-_'e of each cool.-Lng un4L-1-- 3 which side is exDosed to a low-teTmer_=ture air and is low in temperature, with transfer of the result.Lng latent heat to the low-temperature air throug.r. the heat radiating fins 6.

The re-fricerant thus condensed in the condensina portion 8, as shown in FIG. 26A, drops along the inner wall surfaces of the coolina tubes 4 'to the boiling portion 7 located on the lower end side of the cooling unit 3, due to its own weaht. Thus, the refrigerant sealed in the cooiLng tubes 4 of the cooling un-J-t 3, repeats boiling and condensati-on alternately, so that the heat of the hich-te.T.zerature air is transferred to the 1CW-temperature air. In this wav, the heat generated in the electronic parts 11 and 12 can be radiated in the cooling unit 3 which is disDosed in plural stages.

Accordingly, the electronic parzs 11 and 12 can be cooled without mixing of the high-temperature air (clean air in the housing 13) circulating in the high temperature-side heat transfer space 17 of the sealed space 15 and the low-temperature air (foul air outside the housing 13) Circ,,ilating in the low temDerature-side heat transfer space 18.

An effect of this embo d4 ment will be described.

with reference to FIGS. 6A and 6B, the feature of the 0 heat exchanger wherein the coolinq unit 3 is disposed in plural 4 stages in the flowinc direc-Lons of the high-t-emiDerature air and the _7ow--_-_mDerat,,:re ailwill be described.

7TGS. 6A and 6B are sciematic daarams showing tem.-_erature d_istr_'hut_'ons in air ana refr_-geran- flcw-nc U S 4 2 5 directions in the case of __nq a single stage of cocl--na uni-: 3 and in the case of us-4-g:-_"ural,two) stages off cool_nc uni's 3, resoec- __velv. in each of t-ese 6iagra-zis, the axi-c- of ordinate represents temperature (the lower the position, the higher the temperature), while the axis of abscissa represents the direction of fluid (air) flow.

in the heat exchanger (prior art) usLng a single stage of cooling unit 3, as shown in FIG. 31A, the high-temperature air enters the lower portion (boiling port-ion of the coolinq unit 3 from the right-hand side in the figure. with radiation of heat -to the upper portion (condensing portion 8) of the cooling unit, the temperature of the high-temperature air drops and the thus heat-radiated (cooled) air flows out to the left-hand side in the figure. on the other hand, as shown also in FIG. 31A, the low-temperature air enters the upper portion (condensing portion 8) of the cooling unit 3 from the left-hand side in the figure and receives heat from the cooling unit, so that the temperature of the air rJLses and the air which has thus become hot flows out to the richt-hand side of the cooling unit 3 in the figure.

Assuming that the difference -in temperature between -the inlet air and the outlet air in the condensing portion 8 of the cooling unit 3 is -/),Tl, since the heat exchange medium for heat exchance with the refrigerant sealed in the cooling unit 3 is I I a_J_r, the low-temr)erature air is ranidiv heated bv the heat radiat4na fins 6 in the cooling uniz. and its temDerature rises raDidiv a-. the inlet, but this is folluweci by saturation, so that the temrerature difference -1-L-21 (cooling performance) does not become so significant.

4nClUdina On the other hand, in the heat exchanger 2 _L plural stages of cooling units 3 according to the tenth embodLment of the invention, as shown in FIG. 31B, heat.

exchance between the refrcerant sealed in each cooling unit 3 and air can be performed at least in two stages in the air flowing directions. In this case, as indicated with broker -nes in the '_ igure, there is a temperature d 4;_f lfe_rence (a heat ra(:iat_'rg fin temperature difference, and a 'neat receiving fin tempera--ure dlfference be--ween the refrigerant sealed 1'.n the cc)cl4LnQ unit 3 of tne first stage and the re-r4 gerant sealec! in the cool-'rig unit 3 of the second stage. Therefore, as shown in FIG. 313, tne lcw-temperature air reaches its saturation temperature halfway of the condensing portion 8 in the first s-aae of cooling unit 3 and thereafter.4--s temr)erature further r-ses near the inlet of the cooling unil-k 3 of the second stage.

At the same time the hiqh-temDerature air reaches its saturat'on temz)erature at the halfwav of the boiling Qort4on 7 Ln the second stace of cooling unit 3 and thereafter its temperature drops near the inlet of the CO-14na un4t 3 of -he first stage.

7hus, as shown in FIGS. 31A an-_4 311S, the temperature differen-ce _2 -_ 2 ob--a--ne--; n this embod iment (the h e at exc=Qer 25- usIng plural stages of coc-l-L-a units 3) can be made larcer tnaan the tempera'ure difference _,Ii obtaine'_J in --he pr_'cr ar'_ (a heat exc'nanaer using a szaae of co-olling :neref ore, bv rad a- i ng -:he he=- of -ne gh-te=erate air --c --e low-temperature a----, It is possible to L7,prove --he hich-tem,Ler-ature alf coc-l-'ng performance. In th-is wav, '_te cooling effect for the electronic parts 11 and 12 can be improved, and as a result the electronic parts 11 and 12 can operate stably. Further, in this embodiment, when compared with the prior art having the equal radiating performance (cooling performance), the effective heat exchange area (radiat4i-ng effective area) of the each cool-inq unit 3 can be decreased. Consequently, the whole of the ccolJ-na apparatus 14 equipped with such a compact heat exchanger 25 can be downsized.

* Further, since the cooling units 3 used in the heat exchanger 25 are disposed in plural stages so that the high-temperature air and the low-temperature air flow as counter flows, it is possible to provide a temperature difference effectively between the temperature (heat rad'Lating fin temperature and heat receiving fin temperature) of the refrigerant sealed in the cooling unit 3 of the first stage and that of the refrigerant sealed in the cooling unit 3 of the second stage. Thus, by using refrigerants different in temperature, it is possible to raise and lower the low-temverature air and the high-temperature air in turn efficiently. Accordingly, it becomes possible to further imDrove the cooling performance and to downsize the whole off cooling apparatus 14.

AlthouQh this embodiment has been described with reference to the case where two stages of cooling units 3 are used, there may be used three or more stages of cooling units 3 to obtain a larger temperature diffference be-:ween the air inlet and the air outlet of each of the boiling portion 7 and the condensing portion 8 in the heat exchanger 25. The functicn and effect thereof are the same as those described above, so will not. be described here.

5.:.n eleventh embodiment of the present invention wJ-7 be described with reference to FIGS. 32 to 36. FIGS. 32 to 34 show a concrete structure of a cooling apparatus incorporated in an electronic aDDaratus, FIG. 35 shows a concrete struc"-ure of a coolina unit, and FIG. 36 shows a schematic structure of a heat exchanger including cooling units disposed in plural stages.

Cooling units 3 which constitute a heat exchanger 2-5 according to this embodiment are mounted in plural (-Lh:7ee,) staces inclinedly by a predetermined angle within a cas-:ng.

is The cooling units 3 are each divided into a hich temperature-side heat exchanger portion (inside-air-side heat exchanger por-icn) 3a in which a plurality of cooling tubes 4a constit,--Le a boiling portion 7 and a low-tempe-rature-side heat exchanger portion (outs-ide-air-side heat exchanger portion) 3h in whic"n a plural-'tv of cooling tubes 4b constitute a condensing por-L-J;-on 8. The high and low temperature-side heat exctancer por--icns -3a and 3b are interconnected through two f -'rst and second ccn-ection pi-,es 9a and 9t for --efriger-ant circulat-lon.

A cas-4na 20 includes an outer wall plate 26 and a r-ar - - - 7 7 z)arti-r--ion r-la-l---e 2 7, as Jn -.he tentn embodiment. The outer plat-e 26 is centr-=Ily fo=e--; w--'-Lli a sLngle square 1--w temperature-side suction port 26a for sucking a low-temperature air (foul outside air containing a foreign material such as dust or moisture) into a low temperature- side heat transfer space 18. On the upper side of the outer wall plate 26 are formed two square low temperature- s id edischarge ports 26b for discharging the low-temperature air to the exterior through upper centrifugal blowers 21.

On the upper side of the rear parz-:t4on 7 is I - plate 2 formed a single square high temperature-side suction port 27a for sucking a high-temperature air (clean inside airnot containing any foreign material such as dust or moisture) into a high temperature-side heat transfer space 17. on the lower side of the rear partition plate 27, a duct 27b for introducing the high7temperature air after being cooled to electronic parts 11 through one lower centrifugal blower 22, and a duct 27c for introducing the high-temperature air after being cooled to the electronic parts 22 through the other lower centrifugal blower 22, are connected by spot welding or any other suitable means to the lower side of the rear partition plate 27. The ducts 2C 27b and 27c are respectively connected integrally to scroll casings 36 of the two lower centri4fucal blowers 22.

The high temperature-side heat exchanger portion 3a is a multiflow path type heat exchanger pcrt.Lon (an inside heat exchanger portion) which comprises a plural4tv of cooling tubes 4a, a hich temoerature-side upper-end tank 41a, a high temz)erature-side lower-end tank 42a, heat receiving fins 6a ;_nternosed between adjacent cooling tubes 4a, and a side Diate 37a. Since the high temperature-side heat exchanger portion 3a is disposed within the high temperature-side heat transfer szace 7 7 whclis hermet4callv sealed from the exterior bv the housing 13, there is no fear of the portion 3a being exposed to the outside air ccnt-a_-'n_-ng a foreign material such as dust or -r',e low temDerature-side heat exchancer Dortion 3b is a muitiflow pa,_"- hear exchanger ocrt-Lon (an outside.1ne-at exchanger portion) which includes a plurality of cooling tubes 4b, a lower temr)eratare-side upper-end tank 41b, a low temperature-side lower-end tank 42b, heat radiating fins 61D interr)osed between adjacent cooling tubes 4b, and a side plate 37b. The heat exchanger portion 3b is disposed so as to be positioned substantially on the sa-me piane as the high temDerature-side heat exchanger portion 3a within the low temoerature-side heat transfer space 18 which -'s exposed to the outside air containing a foreign material such as dust or moisture. The low te.mDeratu-re-side lower-end tank 42t mav be nclined so that second connection pipe 9b side is positioned lower.

The -first connection pipe 9a _s a -netallic pipe made of same metallic.7,ater--:al as that of the coclinq tubes 4 and -lavina a circ,_--Lar cross section. The connecticn. r)re 9a __C=Unicates te-tween t-e hich temoerat-,are-side uz)ner-eni tank 4-a -_isncsed at the uiDner end of the bo.L'-" ing port-'on 71 ana the de unner-end tank 41_ disrcsed at the =:Der low t-e:rneraz:ure-s_L end o: tl-_ condensinc Dor,_ion 8. --he connect-4or pipe 9a Ls a -6 high-to-low temperature guide means for introducing the vaDorized refriaerant in the boiling portion 7 into the condensing portion 8.

The second connection pipe 9b is a metallic pipe made of the same metallic material as that of the first connection pipe Qla and having a circular cross section. The connection pipe 9b communicates between the low temperature- side lower-end tank 42b located at the lower end of the condensing portion 8 and the high temperature-side lower-end tank 42a located at the lower end of the boiling portion 7. The connection pipe 9b is a low-to-high temperature guide means for introducing the liquid refrigerant which has been condensed in the condensing portion 8 into the boiling portion 7.

An effect of this embodiment will be described.

A cooling apparatus 14 according to the second embodiment is equipped with the heat exchanger 25 wherein the cooling units 3 each including the boiling portion 7 and the condensing portion 8 interconnected annularly through the first and second connection pipes 9a and 9b are disposed in plural stages in the flowing directions of air. With this constructlon, there is formed a circulating flow of refrigerant within each cooling unit 3, and the ccll.Lsion between vaDorized re-frigerant (boiled vapor) and liquid refrigerant (condensed quid) can be prevented. ConsequentIv, the radiatinc performance (cooling performance) of e-ach cooling unit. 3 can be 4 _mproved to a greater extent than in the tenth embodiment. Bv disiDcsina the cooling unit 3 in plural stages, _J-t: becomes possible to further improve the radiating performance (cooling performance') of the heat exchanger 25 as compared with the tenth embodiment.

An twelfth embodiment of the present invention will be described w-'th reference to FIGS. 37 to 39. FIG. 37 shows a heat exchanger to be incorporated in a cooling appa--at,,:s, and Z TGS. 38 and 39 show a sea, 4na structure for the heat exchanger.

T 7, . this embodLment, the heat excl-ancer 25 includes coolina units 3 disposed in plural (three) stages in flowing direct';_ons o-f air. The cooling units 3 each include the boilinc nortion 7 and condensing portion 8 described abcve ';Ln the elevent'. embodi.ment, both porticns 7 and 8 being interccniec-ed annularly through two connection pipes 9a and 9b which extend through a fluid separating plate 2. The fluid separating plate 2 has rectangular or oblong through holes 38 n tWo DCS 4 f ormed _Lticns for passing zherethrough o:': three connection Pipes 9a and three connection pipes 9b respect--vely of the heat exchanger 25.

In each cool-inc unit 31 of -.his emtodi-ment, as comr)a-red W _41-th the elevent-1- emDodiment, a 'ich temnerature-side heat exchancer pcrtion 3a and a low temDera-Lure-side heat exchanaer Dortior are d'LsDlaCed from eac- other on both transverse sides a:d left sides in t'-Ie substantial,,' or.

the same plare. F,.:rther, at tncse- ai--erna-:elv shifted por--i-ons (disLlacet;Dc r--ions.) -L- In are i 14S'posec; t'ne f irs -_ an--; s econd connec-z_-_r z)ioes -a and 91D for refrIgerant. ci--culatlo- 'to connect the high and low temDerature-side heat exchanger portions 3a and 3b annularly with each other.

A sealing structure for the fluid separating plate 2 and the six connection pipes 9a and 9b in this embodiment.

Between the fluid separating plate 2 and the six connection pipes 9a and 9b are mounted split packings 51 and sealing materials 52 and 53 to seal between the -fluid seDarating plate 2 and the six connection pipes 9a and 9t.

The split packings 51 are each constituted by split halves formed by an elastic material such as synthetic rubber for example. Each split packing 51 extends through -,he associated through hole 38 formed in the fluid separating plate 2 and is held by an edge 39 of the through hole 38. The split halves c1re held so as to fixedlv and hermetically sandwich three connection pipes 9a (9b). In the opposed surfaces of the split halves are formed semicircular, ccnnec-ion pipe inser-ing recesses 43 for receiving therein the three connection pir-es 9a (9b), while in the outer peripheral surface of each split haz1f is formed a fluid separating plate inserting slot 44 for receiving therein the edge 39 of the associated through hcle 38 lormed in the fluid separating plate 2.

The sealina material 52 is an e-last--'c material such as silicone type rubber and seals the clearance between three connection pipes 9a(9b) and the asscc-'ated-3 split packinq 511 2 5 The sealing material 53 is the same ela-stic material as the sealina material 52 and seals the clearance between the fluid senaratinq plate 2 and the three connect'-on pipes 9a(9t),.

An effect of this embodiment. will be described.

in the third embodiment, three connection p-J-Des 9a(9b) are hermetically sealed by the associated split pack'na 51.

with edae 39 of the through hole 38 of the fluid separatina plate 2 -fitted in the separating plate inserting slot 44 of the split cackJ_ng 51, the fluid separating plate 2 ard the three connection pipes 9a(9b) are sealed pos--tively bv tle seazling 52 and 53 applJed around the connection pipes and mater--als also around the spllt packing 51.

In the heat exchanger 25 including three stages of cooling units 3, since the connection pipes 9a(9b) are close to one another, the sea': ing work is dif ficul t. However, by adopt-4ng sucli a sealing structure as in this twelfth embodiment, the working ef:ficiency in the process for sealing between the connect-Jon pipes 9a (9b) and the fluid separating plate 2 can be improved and it is possi!Dle to secure the sealing favorably.

in this embodiment, moreover, the hiah and low temoerature-side teat exchanger portions 3a and 3b are dis:)_Iaced from each other on both transverse s.';_des in s'.i!Dstant _a 7 JV the same plane, and the f irsz and second cOn-ect-Icn pipes 9a and 9b for ccnnectng both heat exchanger 7 pcrtions 3'a and 3b are dis:Dosed at those a-ternateiv stif:tea :)Ositlons. Consequently, as co=ar,d with elevent'n embodlmen':: where the first and second ccnnec--4Lcn p.J.-pes 9a and 9b are dl'szosed p-rojec-:inciv on!Dcth -__-ans-,.7erse s--'des and le't s-des in the f_'aures, of eac- coolinc unit 3, t'le zine projecting portions are no longer required and the transverse size of the cooling unit 3 can be shortened by an amount corresponding to the projecting space of the first connection pipe 9a which is a dead space. Thus, the whole of the cooling apparatus 14 equipped with such compact cooling units 3 can be further downsized.

A thirteenth embodiment of the present inven-.-4cn will be descr'l-bed with reference to FIGS. 40 and 4'.. FIG. 40 shows a structure of a cooling apparatus incorporated in an electronic apparatus specifically, and F7G. 41 shows a main structure of a fluid separating plate in a heat exchanger.

In a cooling apparatus 14 of this fourth embodiment, a fluid separating plate 2 of a heat exchanger 25 equipped -,,7ith plural stages of cooling units 3 includes a heat trarsfer accelerating portion 10 for accelerating the heat exchange of high-temperature air and low-temperature air. The heat transfer accelerating portion 10 is disposed in an separat_nc; position for separating between a low-temnerature a.- C-. a downstream (rear stream) side of the heat exchanger 25 and a high-temperature air on an upstream (front stream) side of the heat exchanger. The heat transfer accelerating por-iion 10 includes a large number of concaves and, convexes w41-,_4c'- are formed in rows vertically in the f-'crures by presS4na a flat metallic olate. The concaves and con-vexes are in an alternate1v repeated shape of elongated ridges 61a and elonga7ed recesses 61b in the direct'-on orzhoconal to -.'-,e a 4r flowing directions.

An effect of this embodiment will be described.

In this embodiment, since the heat transfer accelerating portion 10 including alternate concaves and convexes _;_s disposed in the separating position for separat-:nQ 1; between the low-temperature air downstream (rear stream) side of the heat exc-ancer 25 and the high-temperature air upstream (front stream) side off the heat exchanger, the --Fluid separa-4-ia plate 2 can be provide-- with the heat exchange function for both hign-temperature a..'Lr and low-temperatu-re air. Thus, the fluid separating plate 2 can also function to transfer the heat of the high-tem:)erature air to the low-temoerature air, and therefore it is possible to improve the heat conductivity of the whole heat exchancer 25. Further, since the coclJLnu performance for the hich-temperature air can be improved, the Cool 4 whole of;-nu apparatus 14 equipped with the heat exchanger can be downsized.

4 A fourteenth embod-Lment of the present invention w4L11 be described with reference to FIGS. 42 and 43. FIG. 42 shows a structure of a cooling apparatus inccrz)orated in an electronic aDz)ara-LUS specificallv, and FIG. 43 shows a main structure of a fluid sezara-Lina plate in a heat-exchanaer.

ling apparat-L -n a coc -,s 4 according to ths emncdJment, a heat trans'fer accelerating portion 10 is provided at the same Ocsitlon as in the t-Irteent1h em.bod-in-,nt, that is, at the senaratinz poc----icn of a fluid seDaratina Diate 2 o"f a heat exchanaer 25. The heat transfer accelerar4na Dorticr. 10 incl,,:des a larce n,=.!Der of circular recesses 62 wh-'c'- are formed in rows by pressing a flat metallic plate. Also in this fourteenth embodiment, as in the thirteenth embodiment, the transfer of heat between high-temperature air and low-temperature air is accelerated. In this way, the radiating performance (cooling performance) for the hich-temperature air can be improved, and it is possible to obtain the same function and effect as in the thirteenth embodiment.

A fifteenth embodiment of the present invention will be described with reference to FIGS. 44 and 45. FIG. 44 shows a structure of a cooling apparatus incorporated in an electronic apparatus specifically, and FIG. 45 shows a main structure of fluid separating plate in a heat exchanger.

In a cooling apparatus 14 according to this embodiment, heat transfer accelerating portion 10 is provided at the same position as in the thirteenth embodiment, that is, at the separating position of a fluid separating plate 2 of a heat exchanger 25. In the heat transfer accelerating portion 10, a concave-convex metal plate 65a having alternately repeated concaves 63a and convexes 64b is connected to the high-temperature air side of the fluid separating plate 2 by spot welding or any other suitable means, and a ccncave-convex metal plate 65b having alternately repeated concaves 63b and convexes 64a is connected to the low-temperature air side of the fluid seoarating plate 2 by spot welding for example. Also 2_5 in this f-i-fteenth embodiment, as in the thirteenth embodiment, the transfer of heat between both high-temperature air and ow-temnerature air is accelerated. In this wav, the radiating performance (cooling performance) for the high-temperature air can be -4moroved.

Modifications of the above tenth to 'i-een-h - i- L embodiments will be described. The cooling apparatus 14 eauinrze,_4 with the heat exchanger according to each of the above tenth to fiftee-th embodiments is used JLn the case where heat generatlnc elements such as, for examcle, elect-rcnic parts 11 and 12 are recuired to be accommodated within a sealed space.

The case where heat generating elements are required to be accommodated within a sealed siDace includes the case where heat aeneratinc; elements are used under a severe environmental co.-idi----'cn containing oil, moisture, iron POWC_er, ccrrosive gas, or the like, or the case where an inert gas (e.g., helium cas or argon gas) is used to prevent ar-cing or oxidat-Ion of contacts at t he time of electrical intermittence, or the case where it is -recuired to prevent a gas (e.a., hvdroqen fluoride obtained tv decomposition from fluc--ocarbon) harmful to the human bodv from leak-Lng to the exterior.

Altl-ouglr in the above embodiment a corrugated fin-tube tvoe multiflow Dath tvr)e heat excnanaer is used as each of the coolinq unit 3, high temnerature-sir-Je heat exchanaer portion 3a and low --e-izera-tul-e-side heat exc-ancer Dor--ior 3b, there mav be use--4, for the same purpose, a plate f-J--tube type heat -C 4 n r 4 n - uh. e le _= t exc-langer, a - _L_ serDenzlne heat exchancer ccns-zitute-_4 bv a meanderinalv C7U_:--C a bent fla-_ -='-e, or a drawn-cur) --.,:e heat excil-a-cer in large number c-f laminated cooling tubes ea-c" constituter-4 ty laminating two pressed plates. As the heat receiving fins 6a and radiating fins 6b there may be used slit fins or louver fins.

Although in the above embodiments a high-temperature air heated by heat generating elements such as the electronic parts 11 and 12 is used as the high-temperature fluid (inside fluid) within the housing 13, there mav be used, as the high-temperature fluid, a high-temperature liquid such as, for example, cooling water or oil (includina hvdrau-',ic oil and lubricating oil) for cooling the heat generating elements. In the same manner, as the outside fluid (outside air) outside the housing 13 there may be used not only a gas such as air of a low temperature but also a liquid such as water or oil of a low temperature. In these case, pumps are used as inside fluid circulating means and low-temperature fluid generating means.

As means for actuating pumps and centrifugal fans 31 anci 34, there may be used not only such electric motors 32 and 35 as in the above embodiments but also an internal combustion encine, water mill, or windmill.

A sixteenth embodiment having an apparatus r controlling a temperature within a closed body of the p--esenL 4 4 invention incorporated into an elect-ron..1-cs aDDaratus will- be described hereinafter with reference to the draw';_ngs. FIG. 46 si-ows the entire construction of an elt--c-tronics apparatus.

An electronics apparatus 1 is, for example, a rad4c base stat-4on anmaratu,s of a mobile radio tele=hone such as a cordless telephone, a car telephone, cr the like, which includes a housing 13 -or hermetically housing electronic Darts 11 and 12 therein, and a cooling apparatus (a cooler) 14 incorDorated into the housJLng 13 to cool the electronic Darts L 11 and 12, and the like.

The electronic part 11 is a heating element wtich Derforms a P.-edeterm_'ned operation when an electricity is suzzlied thereto a n d generates heat (,for example, a semiconductor switchLng element constit,,:t-ing a high frequency switching ci_-cuit incorDor-mted in a trans -rece _Jver). The electronic part 12 is a heating element wliclh, performs a Dredetermined oneration when an electricity is supplied there-to and generates heat (for example, a semiconductor amplifying element such as a Dower transistcr incorporated in a power amplifier).

The housing 13 is a closed body for herme-L.4;-cally sealina the interior from the exterior and is formed ±-herein with a sealed sDace 15. The sealed space 15 is completely hermeticallv separated from the outside by means of a fluid separa t 4 ng plate or the lJke of -he cooling apparatus 14 C 4 des _;_bed later in craer to Prevent the performance ofthe electronic parts!I and 12 -from beIng deterlorated due to the deL-osi-icn of forei-n materlal suc'-I as dust anzi water tC the electron--c Darts 11 and 12.

T'-,e sealed s-:)ace 15 Ls part]-tiLned into an ellectronic 25:)a_-t acccmmoda.,tina sDace 16 for accommodating parts 11 an--4 12 therein anl a hig-;-temcerat-Lire-side heat 4 transfer sT-)ace 17 as a ns_'de passage, 1--y means of the fluid separating plate of the cooling apparatus 14 and the casing of the cooling apparatus 14. The flow path area of the high temperature-side heat transfer space 17 is narrow on the upwind side in order to minimize the depth size of the cooling apparatus 14, while the flow path area of the same space on the downward side is wider. Further, the housing 13 is formed with a low- temperature- side heat transfer space 18 as an outside passage hermetically sealed from the high- temperature-s ide heat transfer space 17 by the fluid separating plate.

The cooling apparatus 14 will be described below with reference to FIGS. 46 to 49. FIGS. 47 to 49 show the detailed construction of the cooling apparatus 14.

The cooling apparatus 14 includes a casing 20 provided integral.with the housing 13, a heat exchanger 21 for sett-ing an air temDerature within the closed space 15 to a level not higher than an upper limit temperature (e.g., 65: C), two upper-side centrifugal type blowers 22 for generating an air flow of a low-temperature air (a low temperature fluid), two lower-side centrifugal type blowers 23 for generating an air flow of a high-temperature air (a high temiDerature fluid), an electric device 24 for maintaining the air temperature in the closed space 15 at a level not lower 'than a lower-1 fmit temperature (e.g., Oc C), a controller 25 for control-ling the 4 supply of electricity for the elec--r--- devices of the coc-l-'ng apDaratus 14, and the like.

The casing 20 includes an outer wall plate 26 disposed on the oute--most side of the elect--onics aznaratus 1, a rear partition plate 27 surrounding the high-temperature-side heat transfer space 17, and -he 14 L_ -Ike. These outer wall plate 26 and rear partition plate 27 are secured to the housing 13 by the bonding, e.q., a spot welding or by using the fastening means such as screws or bolts.

--o the central Dortion of the outer wall p7ae 26 is oDened a single square low-temperature-s Lde suction port 26a for suckling Iow-temperature air (-.Lo,,:l outside air ccntaininc foreign material such as dust or water) into the low tempera ture-side heat transfer space 18 from the outside.

Further, to the upper side of the outer wall plate 26 is opened two square low-temperature-side discharge ports 26b for discharging low- temperature air to the outside from the u:)Der SLde centrifugal type blower 22.

To the upper side of the rear partition plate 27 is opened a single square high-temperature-side suction port 27a for sucking h.Lgh-temperature air (clean air not contain ing foreign material such as dust or water) into the hiah S 4 temiDerature- _de heat transfer space 17 from the electronic part accommodating space'16.Further, to the lower side of -the rear-side partition plate 27 are joined a duct 27b for ntroduc4nq cooled h_gl, temperature air from one lower-side centrifuga7 type blower 23 to the elect-ronic part 1-1, and a 4 UC4 na duct 27c for cooled hia'- tcmnerature air from the other lower-slzle cent---4fucal tvDe blower 23 to the ele-c-t-ro-i-c part 12 -'-v means sucl as a spot weld_4na. The duct-s 271D and 27C are respec-ively intezrally connected to a scroll casing 36 off -Be- to lower side centrifugal type blowers 23.

Next, the heat exchanger 21 will be described in detail with reference to FIGS. 46 to 51. FIG. 50 shows the detailed construction of the cooling unit, and FIG. 51 shows the schematic construction of the cooling unit.

The heat exchanger 21 includes a fluid separating plate 2 for hermetically separating high temperature air as internal air (inside air) which circulates within the housing 13 from low temTDerature air as external air (outside air) which circulates outside the housing 13, and a multi-stage (three-stage) type cooling unit 3 incorporated in the fluid separating plate 2 in the state extending through the fluid separating plate 2.

The fluid separating plate 2 includes one wall surface (a part of the casing) of the housing 13 which constitutes one wall surface of the closed space 15 interior of which is at a high temperature and one wall surface of the low temoerature-side heat transfer space 18 interior of which is at a low temperature. The fluid seoara-Ling plate 2 is made of a metal material which is superior in heat conductivity, such as aluminum, and is integrally brazed with -:he cooling unit 3 and the casing 20 so as to hermetically div_de between the closed space 15 including the high tempe-rature-s-4de heat transfer sz)ace 17 and the outside incluclinc thtlow te.mDera,::ure-siae heat transfer space 18. The fluid separat_'ng plate 2 is!Dored wi-,r) a plurality of elongated; rec-anaular or otlona through-holes through which connection pipes of the c--ol-'ng unit 2 extend (described later) at predetermined intervals.

The fluid separating plate 2 may be a separate elements (for example, split plates).

The cooling units 3 are incorporated within the casing 20 in clufal staces (three staces) in a state inclined at a predeterm--ned angle and is divided into two portions, a high temperature-side heat exchancer (inside-a.'r-side heat exchanger) _3 a and a Iow temperature-side heat exchanger (outs ide-alr-side heat exchanger) 3b into which is sealed a fluorocarbon type or freon type ref-ricerant, the hich temperature-side and low- temperature-side heat exchangers 3a and 3b being connected by two ref--icerant circulatina first and second connection pines 9a and 9b.

The high temperature-s.-Lde heat exchanger 3a is an inside heat exchanger which is a multi-flow pass type heat exchanger including a plurality of cooling tubes 4a, a high temnerature-side upper end tank 28a, a hiczh-temnerature-side lower enJ tank 29a, and a heat receivinq fin 6a _Jnter)osed between the coolirg tubes 4a adjacent to each other. To -.,ie opposite sides of the hich-temperature-side heat exc.anqer 3a are joined s--de plates 30a which func-_'cn to -Fasten tc the fluid sepa-ratIng pl-ate 2 and the casInq 20 by fastening means and which also function to reinfcrce a:_'uralitv of cooling tubes 4a ana; a plurali-::v of heat receiv_'na fins 6a. Since the ,-ch- temper_::itu_re-side heat exchancer -a iS disnosea; wit'-in ':ne high- ':emcera':ure-sidle '-eat transfer sz)ace 17 seale-_ -'--cm t'ne outside '--v the housing 13, ttere is no zoss_-b_4_7_-t,; --hat the _9C_ high-temperature-side heat exchanger 3a is not exposed to the outside air containing foreign material such as dust or water.

The plurality of cooling tubes 4a are made of metal material which is sur)ericr in heat conductivity, such as aluminum or copper, which are formed -into flat tubes (for example, width is 1. 7 mm and length is 16 0 mm) haV4 nq an elongated rectangular shape or oblong cross section. The hiLgh temDeratu--e-side heat exchanger 3a formed from these cool4nq tubes 4a is constituted as a refrigerant tank (a boiling portion) 7 in which a refrigerant sealed therein is boiled and vaDorized bv receiving heat from high-temperature air.

The high- t emperature- side upper end tank 28a and the high-temperature-side lower end tank 29a include a core plate provided. on the cooling tube 4a side and a substantially inverted-U shape tank plate joined to the core plate. Either the high tempera ture- side upper end tank 28a or the high temDerature-s4Lde lower end tank 29a is provided with only one refrigerant sealing port (not shown) for sea7ina a refricerant into the cooling unit 3. The refrigerant is sealed into each cooling tube 4 of the high temperature-side heat exchanger 3a uz to a height at which a licuid level -LI-.erecf corresnonds to a position of the upper end of the cooling tube 4a, that is, a eight of the boiling portion 7. The refr--:aeran-L is sealed after the heat. receiving fin 6a has bee.,., brazed to the cccl'na 2 tube 4a.

The heat receiving fin 6a -S a CorrUCat4nC fin -L in wh--ch,ihin sheets (for examnle, sheet thickness is about 0.02 to 0. 50 mm) formed of metal material which is superLor in heat conductivitv, such as aluminum are alternately pressed and bent into a wavv s1lane, the fin 6a beina brazed to a flat cuter wall surface of the cooling tube 4a. That is, the b azJiq_ is nerformed in the state where the outer wall surface of the coolinc tube 4a and the heat receivinc fin 6a are fused.

he low-temperature-side heat exchanger 3b s an outs-i--;e heat exchanger which is a mult---flow pass type heat exchanger including a plurality of cooLing tubes a low temperature- s ide upper end tank 26b, a lcw-temperature-side lower end tank 29b, a heat receiving fr 6b interposed between the coolina tubes 4b ad4iacent to each other, and a side olate 30b. The low- temperature-side heat exchanuer 3b is disnose-_4 so as to-be positioned on substantially the same plane as the high- temperature-side heat exchanger 3a in the low de heat transfer space 18 exposed to foreign temperature-s L_ material such as dust or water.

The plurality of cooling tubes 4b are formed to have t. h e same shape as the coolina tubes 4 a. The -,OW tempera-:iu_-e-s.41_de heat exchanger 3b including these cooling tubes 4'-- is ccnst-:Ltu-:ed as a vaDor_zed refricerant t-ank (a condensinc 8 -'r. which the vap3r_4zed -re-fricerant bc--'2-ed the '--oilina Dcrtion 7 is condensed and liquefied bv the re easL= -ne heat of' the vaDcrize-_ refricerant tci7-4 -:)crticn 7 to the low-tem.neratu_-e a-,--.

-Le _7cw-temr)er_=-_ure-s.Jde_ upper end 'iank 28t and the low- lower end tank 29'-- include a core plate and a substantially inverted-U shape tank plate similar to the high-temperature-side upper end tank 28a and the high temperature-side lower end tank 29a.

The radiating fin 6b is a corrugating fin fo=ed in the shape similar to that of the heat receiving fin 6a, and; is brazed to a flat outer wall surface of the cooling tube 4b. That is, the brazing is performed in the state where the outer wall

surface of the cooling tube 4b and the heat receiving fin 6b are fused.

The first connection pipe 9a is a metallic pipe wtich is formed to have a circular cross section by the same metal material as the cooling tube 4b, and --:;.s communicated with the high-temperature-side upper end tank 28a provided on the uppe-r end of the boiling portion 7 and the low-temperature-side upper end tank 28b provided on the upper end olf the condensing portion 8. This connection pipe 9a is a high-to-low temperature guide means for introducing the vaporized refrigerant boiled and vaporized JLn the boiling port..on 7/ to the condensation portion 8. Wh4 The second connection pipe 9b is a metallic pipe -ch is _-!ormed to have a circular cross section hv the same metal mater'al as the first connection pine 9a, and is communicated with the low-temperature-side lower end tank 29b mrovided on the lower end of the condensina -ort-4on 8 and the hic:- I e 1 temperature-side lower end tank 213a Prov--:ded on the lower end of the!Dciling portion 7. This connect-'On pJLpe 9-'- is a low-to hich temnerature cuide means for introducing the vancrized refrigerant condensed and liquefied in the condensing portion 8 to the boiling portion 7.

Two upper-side centrifugal type blowers 22 each include a cent--ifugal type fan 31 for generating an air flow in the Lde heat transfer space 18, an electric motor low- enmerature-s-L 32 for rotatinc the centrifugal type fan 31, and a scroll casing 33 for rotatably receiving the centr-'fugal type fan 31.

Two lo-wer-silde centrifugal tvve blowers 23 each 4 nc7ude a centri'ucal type fan 34 for generating an air flow in the high- temr_)erature-side heat transfer space 17, an electric motor 35 for rotating the centrifugal type 'Lan 34, and a SCrO17 . r 4 casing 36 for ro-:atablv -receiving the cent fugal type fan 34.

The electric heater device 24 will be described in detail hrereinafter with reference to F 7G. 46, FIG. 47, and FIGS. 52 to 55. FIGS. 52 and 53 show the detailed cons truct- _o of the electric heating device 24.

The electric heating device 24 includes an electric heater 5 to be attached or detached thrc,.,ah an opening (rict S 4 shown) provided on the ide surface at one side of the casing 20, and a heater mounting device 6 for fixJLna the electric heater 5. The opening is openei and; closed by a hatch 2Ca as indicated '--v the two-dot chain line in F:G.

The electric neater 5 is disposec; at a downstream s-4--;e oL tl-e 'r.-:zh temnerat,.:re-side hea-_ exchanaer 3a of the cc--I'n' unlt 3 in t'nle hig', temnerature-side heat transfer space 17, of the '-Ious_rc 13 in a, flowing direction of '-_4qh-_--_-:Derature a__-.

The electr_4c heater 5 L's for hea--ing air flowinq thr--ug- the high temperature-side heat transfer space 17 so that the temperature in the closed space 15 is higher than a lower limit temperature. This is because, when the temperature in the closed sDace 15 of the housing 13 is lower than the lower limit temperature (e.g., 0: C), the performance of the elec--rcn-ic parts (e.g., semiconductor elements) 11 and 12 deteriorates.

The electric heater 5 in this embodiment has the hea-Lina value of, for example, 1.2 kW.

The electric heater 5 includes, as shown in FIG. 54A, four heater bodies 53 to 56 hung between a pair of support plates 51 and 52 opposed to each other, a plurality of plate fins (radiating fins) 57 provided on the two heater bodies 53 and 54, a plurality of radiating fins (radiating fins) 58 provided on the two heater bodies 55 and 56, a front-side flange 59 secured to one support plate 51, and a back-s";_de flange 60 secured to the other support plate 51.

- For the two heater bodies 53 and 54, for example, sheath heaters are used. A heater terminal at one s-;Lde is connected to a controller 25 by a conductor, and a heater terminal on the other side connects the both.

For the two heater bodies 55 and 56, -for examzle, sheath heaters are used similar to the two heater bodies 53 and 54. A heater terminal at one side is connected to a cont--c-Lier by a conductor, and a heater term:_nalf on the other s-'de connects the both.

A plurality of plate fins 57 and 58 '_FL:nc-:ic)r- as radiating fins. A number of thin sheets (for example, thickness is about 0.02 to 0.50 mm) formed of metal mater 4 .al which is suDerior in heat conductivity, such as aluminum are disposed at 4..ntervals of fine fin pitch (for example 5 mm) to release ne-at generated in the four heater bodies 53 to 56 to air cl_-culating in the closed space!5.

ff lat-shape configuration from met-a-I material having a hich strength and is provided on the opening side of the casing 20 to hold and fix one ends (openinq-side ends',t of the fc-L:r -eater bodies 53 to 56. The flange 5 f-unctions as a front-side mounting stay for being connected to the heat mounting device 6.

The front-side fiance 59 is -fastened while being in a state as-to closelv contact with one support plate 51 using a fasteninc means 61 such as two screws, nuts or the Externally of the portion projected from the support plate 51 of the front-side flange 59 is formed a semi-circular f--cnt side recess portion 62 as a recess portion on the opening side fitted in the heater mounting de V 4 ce 6. The front-side flange 59 is further provided with an internal thread hole 66 engaged 4 W-th fastening means 63 such as a screw as fixing means at, a substantialiv se.7.,i-c]L_-c,_,Iar por-tion projected downward as s-)own in FIG. 54B.

The back-side flanc:e 60 Is foimed so as to have the same shane -from the same material as the f'--ont-side fiance 59, and Ls d;_'Sr_-_sed ooDosedlv of --he fronz-side flance 59 on the reversed s-'de (deeo with respec- tc the cr-en-;_nc s_,_4e 04 the casing 20. The back-side flange 60 holds and fixes the other ends (back-side ends) of the four heater bodies 53 to 56.

The flange 60 functions as a back-side mounting stay for being connected to the heater mounting device 6.

The back-side flange 60 is fastened and fixed while being in a state as to closely contact with the other suPPort, plate 52 using fastening means 64 such as two screws.

Externally of the portion projected from the support plate 51 of the back-side flange 60 is formed a semi-circular back-sJI.Je recess portion 65 fitted in the heater mounting device 6. The back-side flange 60 has a round hole portion (an engaged portion) corresponding to the internal thread hole portion of the front-side flange 59.

The heater mounting device 6 has a guide shaft 73 provided integral with the casing. 20 and hung between a pair of front-sides of the electric heater 5, a pair of front-sides -for holding and fixing.the back-side flanges 59 and 60, back-side brackets 71 and 72, front-sides thereof, and the back,-s--'de brackets 71 and 72 so as to axially slidably fit the pair of S 4 front-sides of the electric heater 5 and the back- _Lde flances 59 and 60.

The front-side bracket 71 is formed so as to have a t 4 subst-an -ally L-shape from metal material 'navinq high streng--, and has a connection plate 74 in -the --fo=- of a flat plat-e 2 connected to the inner surface of the outer wall plate 26 of the casing 20 by means of a spot welding or the 1-'ke, and a binding plate 75 bent perpendicular to the conne--t--:on plate -174.

The binding plate 75 is formed with an internal thread hole por-ziion 76 into which is inserted fastening means 63 such as a screw. In this way, the bindinq Dlate 75 fastens the front-side flange 59 using the fastening means 63 such as a screw serve a s restrict-irg means for restraining (restricting) the movement of the front-s-Lde flanae 519 (the electric heater 5) in the horizontal direction parallel to the ax.4al direction of the guide shaf-_ 73 and in the vertical direction to the aforesaid horizontal direction. lFurther, the binding plate 75 supports the guide shaft 73 by connecting the guide shaft 73 by means such as a spot welding in the state where the end of the guide shaft 73 passes through.

The back-side bracket 72 is formed so as to have -he same shaDe from the same material as the front-side bracket 71, an:l has a connection plate 77 in the form of a flat plate, and a binding plate 78 bent in the direction perpendicular to the connection plate 7/7.

The binding plate 78 is firmly -fixed in a sta-e where a sinale Din (a projecting portion, an engaging port. -Jon) 7 9 is projected inward. Tn this wav, the binding plate 78 funct-ons as restr_cting means in which the p= 79 is fitted in a round hole portion 8C of the back-side -fflanae 60 to restrain (,restr-'ct) the movement c-ff the I-Jack-side _'F-Iange 6 (elec':ric heater 5', in the horizcrtal direc-:_'cr. parallel to t-;e ax-,-;-l direc-::ion of the guide shaft 73 an-_J _J- the vertical _J.4_rec-ion -with res:;ec-- -Lo the aforesaid hor'Lzcn-_a2. direction. T-e ent of the cuide shaft -13 is connectea to the b indina Dla-::e 7 8 jDV means such as a spot welding to support the guide shaft 73.

The guide shaft 73 is a metal shaft formed so as to have a circular or cylindrical cross section as shown in FIG. 55A. The guide shaft 73 is for guiding the electric heater 5 t 4 between the moun ng location and the opening when the ellect-ric heater 5 is attached or detached.

In the guide shaft 73 is fitted axialiv slidably the front-side recess portion 62 formed in the front-side flange 59 and axially slidably the back-sJLde recess portion 65 formed in the back-side flange 60. In this way, when the electric heater is mounted on the heater mounting device 6, the guide shaft 73 functions as restricting means for restraining (restricting) the movement of the front-side and back-side flanges 59 and 60 (electric heater 5) in the vertical direction with respect to the horizonal direction parallel to the axial direction of the guide shaft 73.

The controller 25 is.for controlling electric devices of the cooling apparatus 14 such as an electric motor 32 for two upper-side centrifugal type blowers 22, an electric motor 35 for two lower-side centrifugal type blowers 23 and an electric heater 5 (four heater bodies 53 to 56) on the basis of a detected temperature in the closed sDace 15, detected bv a temperature sensor 9 formed from a heat sensinc element such as a thermistor.

When the temDerature in the closed space 15 4_s hicher than the lower limit temperature (e.q., O: C), the controller operates two upper-side centrJLfugal type blowers 22 and two lower-side centrifugal blowers 23 in a Hi (large air amount) or Lc (small air amount) mode to turn OFF the electric motor 5.

Further, when tile temr)erature in the closed space 15 is lower than the lower!Lmit temperature (e.g., 0: C), the contrcller 25 turns OFF the elect - 4 - motor 32 for two =er-side centr-4--F,L:cal tvpe blowers 22, operates the electric motor 35 for two lower-sije centrifucal tvne blowers 23 in Hi amount) or:,c (small air amourit) mode, and turns ON the electric motor 5.

in the following, the method for mounting the e-lectr-'c heater 5 to the heater mounting device 6 according tc --his embod 4 -Iment will be briefly described with re:ference to F7G. 47 and FIGS. 52 to 55.

When the ellectric heater 5 is mounted on the heater mount-4ng device 6, f-'rst-7y, the hatch 20a is opened so that the opening prcvi-ded in the side on one side of the casing 20 opens. In the heater mounting device 6, the connection pliates 74 and 77 o-jff the iDair of f--ont-side and back-side brackets 71 and 72 having the guide shaft 113 held and fixed are secured to the inner side of the outer wall plate 26 of the casIng 20 using means such as a spot welding.

Nex':, as shown in FIG. 54-L., the heazter 5 havina rarts _'ncorDcrated:herein is inserted in the di_-ec'__-'cn indicatez; b,; the solid line s',-cwn in FIG. 52 frcm the opening. At this -.--'me, ttne fror-z:-side and back-s-',--;e recess corticns 6',2' and 65 of the -,a';_r cf f_ront-sLde and back-side C',ances 59 and 60 o-f the elec-tr-c heater 5 are fr_'tted the _1C0_ guide shaft 73, and in this state, the electric heater 5 is inserted in the direction as indicated bv the solid line shown in FIG. 52 along the guide shaft 73. in tnis way, even if -he weight of the electric heater 5 is heavy, an OiDerator can inserts the electric heater 5 by one hand.

Next, when the back-side flance 60 comes in contact with -he back-side bracket 72, the insert-'na work for the electric heater 5 is completed. Then, the round hole portion of the back-side flange 60 is fitted _.- the pin 79 secured to the back-side bracket 72, and the back-sJLde flanae 60 is restrained in the back-side bracket 72 in the horizontal plane parallel to the axial direction of the guide shaft 72 and restrained in the vertical plane wJL--h respect to the horizontal direction.

Next, the internal thread hole port'-on 76 of the front side bracket 71 is fit into the internal thread hole portion 66 of the front-side flange 59, the operator puts one hand into the opening of the hatch 20a to insert and t4ghten the fastenina means 63 such as a screw into both the internal thread hole Dortions 76. In this wav, the front-side flancze 59 is restrained in the 11--ont-side bracket 71 in the horizontal z1ane Darallel to the axial direction of the uude shaft and fixed in the vertical plane with respect to the horizcntal irec-:: ion From the foregoing, the mou,it4Lna operation c_ -e electric heater 5 to the heater mount-4-a device 4ntearal wi-t the housing 13 (casing 20) -'s complete-c-4.

L n the f ol I owinc, the method:"cr Lna the electr' - _101- heater 5 from the heater mounting device 6 will be described with reference to FIG. 47 and FIGS. 52 to 55.

When the electr--:c heater 5 is detached from the heater mCuntinc device 6, the oDeration is performed -'in the procedure reversed to that of the mounting operation. hat is, the czerator puts one hand into the opening of the hatch 20a to remove the fasteni-Q me-7-ns 63 such as a screw so that the C, o-f the front-side flange 59 by the front-side bracker-- 71 is rele_=sed, and the birding between the p4n 79 and the round hole portion 80 is released to remove the back-side f"lange 60 from the back-side bracket 72.

Next, the electric heater 5 is detached along the guide shaft 73 in the d_rection reversed to the mcun-tinci operation of the electric heater 5. At this time, the front-side and back side recess portions 62 and 65 of the pair of front-side and back-side flances 59 and 60 can be pulled out in -the state as to be f-4tted in the quide shaft 73, and -therefore, the operator car, pull out the electric heater 5 by one hand even if the weicht of the electric heater 5 is heavv. From the foreacina, the det_;---chnc operation of the electric heater 5 from the heater mo--int-4na device 6 is completed.

Ln oDeraticn (funcon) of 'the coolina arDr_ara-!:,as 14 acccrd_r.g c this eri_'-c-_3iment will be briefly described with 'ehen the tem,,erature 4n the c--cse,-; space 15 ofthe hc,,:s_nc 13 is hig.-er than the lower li_mJt- te=)erature (e.g., 0- C), the supply olf the electrJci-:y to the electr-lc mo-z:cr _32 -102- for two upper-side centrifugal blowers 22 and the electric motor 35 for two lower-side centrifugal type blowers 23 is started, and the centrifugal type fans 31 and 34 start to operate. In this wav, a flow of high-temperature air (clean inside air not containing foreign material such as dust or water, internal fluid) circulates in the closed space 15 (high temDerature-side heat transfer space 17) in the housing 13.

Further, a flow of low-temperature air (foul outside air containing foreign material such as dust or water, external fluid) circulates in the low- temperature-side heat transfer space 18 outside the housing 13.

in the cooling unit 3 mounted while being in the state as to pass through the fluid separating plate 2 of the housJng 13, the.refrigerant sealed into each cooling tube 4a of the high- temperature-side heat exchanger 3a receives heat transmitted by the high temperature air through the heat receiving fin 6a and becomes boiled and vaporized, as shown in FIG. 51. The vaporized refrigerant passes through the!igh temperature- side upper end tank 26a and the first connection pipe 9a and becomes condensed and liquefied on the inner wall.

surface at the condensing portion 8 provided on the low Ure_S4 temDerat -Lde heat exchanger 3b which is exposed to the low t eTnDerature air to be a low temperature, and the condensed latent heat is transmitted to the low LemDerature air -_hr3uzh the radiating fin 6b.

The refricerant condense,_4 and liauefied at h e condensing pcrt-'cn 8 is transmitted to --he inner wall surface -103- of each cooling tube 4b due to its own weight and transmitted to the low temperature-side lower tank 29b and thesecond connection pipe 9b and drops on the boilina portion T-,rov-7aed on the high temperature-side heat exchanger 3a. As described above, the re-friaerants sealed into the coolina tubes 4a and 4b a!-Lernatelv reiDeat the bo.';_Iina and vaporization, a n d condensation and liquefaction. In this wav, the heat of '-J_91_ temperature air is moved to the low -emperature air, and it. is possible to radiate the heat generated in the electronic parts 11 and 112 at the multi-stage cooling unit 3.

Accordingly, the electronic parts 11, 12 can be cooled without the mixture of the high-temperature air (clean air in the hous-'ng 13) which circulates in the high tempera-ure-side heat tr&ns fer space 17 of the closed space 15 and the low temperature air (foul air outside the housing 13) wlich circulates in the low- temr)erature-s ide heat transfer sDace 1-8.

In the case where the temnerature in the closed snace 4 of -:he housing -13 is lower than the lower _L_t temperature (e.g. 0- C), the electr-Lcitv is suD=lied to the electric heater 5 and heats air flowina throug- the h'-h- _n order to rrevent the defect_-.,e operation o,-.;' the electronic parts 11 and 12. At this -:iime, two unper-s4Lde centrifuual blowers 22 remain s-Lopped.

On the other hand, -the hic'n temnerature air in close,_4 s::)a--ce 15 o-' the hcus.4n- 13 _Iows into the annaratus!a frcir. -L-'ne electro-1-4c Dart. accommodat.-,Lnc -or acc_=.,oda'_ilng tne electronic -:arts 11 and 12 -:"ere_4n and -104- from the high temperature suction port 27a formed in the back-side partition plate 27 of the casing 20. The hiah temperature air having flowed into the cooling apparatus 14 Dasses throuch the narrow passage surrounded by the fluid separating plate 2 and the back-side partition plate 27 and thereafter passes through the high-temperature-side heat exchanger 3a. That is, the high- temperature air passes between the plurality of cooling tubes 4a, and the heat is received by the heat receiving fin 6a.

when the high-temperature air passes through the narrow flow passage, the flow velocity of the high-temperature air increases. when the electric heater 5 provided with a plurality of plate fins 57 and 58 of fine fin pitch is installed in the narrow flow passage, the pressure loss increases so as to lower the circulating air amount of the high-temperature air, and the radiating performance of the electric heater 5 lowers.

in order to overcome such inconveniences as noted above, in this embodiment, the electric heater 5 (the electric heating device 24) is installed at the downstream side of the high temperature-side heat exchanger 3a of the cooling unit 3 through which high temperature air circulates, as shown j.- -,TG.

47. In this way, the pressure loss in the closed space 15 (particularly, the high-temperature-sJ-6e he_az transfer space in the housing 13 can be greatly red,-,ced.

An effect of this embodiment will:--e jescribed.

As described above, in this embodiment, a -lurali-iv of e -105- plate fins 57 and 58 formed from thin sheet members are disnosed on the electric heater 5 to secure a heat transfer area- however, since the 'Lin pitch is extremely dense (Iffine), when the flow velocity of the air is 'n-Jah, the pressure loss increases so that the circulating air amount of the ventilation svstem reduces, and the radiating perfornziance of the electric heater 5 deteriorates.

On the other nand, since an effective heat-exchange area of the high-temperature-side heat exchanger 3a is large, the flow velocity of the high- temperature air lcwers at the downstream side of the higIn-temperature-side 'neat exchanger 3a.

Therefore, in this embodiment, the electrIc heater 5 is installed at the downs-L-ream side of' the hich-temDerature-side heat exchanger 3a of the cooling unit 3 through which high temperature air circulates. In this wav, the pressure loss in the housing 13 (the high temperature-side heat transfer space 17) can be greatly reduced to prevent the radiating perfcrmance e_4 of the electric heater 5 -from being det --crated. In this way, the temz)erature in the closed space 15 in the housing 13 can be maintained at an o,)timum value.

1 -.1 - - urtner, n t-1-,is embodiment, the mountinq operation for moun-::_na --'-,e elec--r-'-- heater 5 to the '-eater mountina dev_'ce 6 and the de-r-achinq operation fcr detaching the elec-='c heater from the heater mounting device 6 can be performe-_ extremely s-mnly. --Ie Pin 7/9 --f the back-side bracket 72 cf the 'ne_=ter mounting device 6 is Lnse_rted into the --cund '.-io le port-4--n 30 of the ba--k-s';_de flance 6-3 of the electric heater 5 sc as to -106- restrain in the direction vertical to the axial direction of the guide shaft 73, thus providing a construction which is superior in anti-vibration.

In this embodiment, the cooling apparatus 14 is Qrovided with the heat exchanger device 21 having the ccoling units 3 disposed in plural stages in a flow direction of air in which the high-temperature-side neat exchanger 3a forming the boiling portion 7 and the low-temperature-side heat exchancer 3b forming the condensing portion 8 are annularly connected bv two first and second connection pipes 9a and 9b. With th.:Ls construction, the circulating flow of refrigerant is formed in each cooling unit 3 to prevent the collision between the vaporized refrigerant (boiled vapor) and the liauid refricerant (condensed liquid), thus further improving the radiating S 4 performance (cooling performance) of a -Lnale cooling unit 3.

Since such cooling units 3 are dispcsed in plural stages, the radiating performance (cooling performance) of the cocl-Lnq units 3 of the heat exchange device 21 can be further improved-4.

Modifications of the sixteenth embodiment will be described.

The cooling apparatus 14 provided with the heat exchanger device 21 according to this emb-odiment is utilized in the case where the heating elemen--s such as the electr=_'_ parts 1-1 and 12 need be accommodated in the closed sDace. The case where the heating elements need be accorrLmodated in the closed sDace includes the case where '-Iea-L--'na elements are use-_ C under the severe environmental condition containing, -cr -107- example, oil, water, iron powder, corrosive gases, etc., the case where inact -4ve cases (helium gas, argon gas, etc.) are used to prevent arcing or oxidation of ccntac,s at the time of electric intermittence, or the case where gases harmful zo the human body (for exam.cle, such as hydrogen f1uoride decomposed from -flucrocarbon) are prevented 'rci-, leaking outside.

in this emhodimen":, a multiflow pass type I-i e a exchanger having ccr-ugating fin t-.:bs is used as tne cooling unit 3, the hJ;_gh temzerature-side hea-z: exchanger 3a and the low temzerature-side heat exchanger 3b; nowever, a heat exchanger having plate fin tubes, a heat exchanger having fine pin-fin tubes, a heat exchanger of a serpenzine type having flat tubes bent in a zigzaa manner, and a heat exchanger off a dra-v,;n-c,_,p type having a plurality of laminated cooling tubes in which two pressed plates are connected to each other, may be used as the cooling unit 3, the liah temperature-side hea-- excil.ancer 3a and the low temr)erature-side heat exchanger 3-'-. S 1 i - f i n s o r louver fins may be used as the heat receiving fin 6a or the -adiat4na fin 6b.

Ln this embo-_;Lment, h-;_qh-temDera-:=e qas suc- as -4ch e7 teriDerat'are air, heated bv heating -ements suc- as the electronic Dar's 11 and 1-2 is used as -4n the housina 13- and n4gh-tempera--,:re fluf6 as fu-d in the cas-rig (47-s-de a-,; L L however, coclinq water f c r c o o I i r, a e h e n a e I em e r,.,7 s su cin as 7 -ihe electro-,-4c na 1 and 12 and h-'gh-te-mr)erature _'_'cuid s--,ch as o' (nc-udinc oil and 1,L:h_-_4c_7-t_4nC o.4-7') ma-,.7 be used U T as a h_4#--_-_mLiDera-r_ure --he same manner, nct on_'-,' LOW- -108- temperature gas such as low temperature air but also low- temverature licuid such as water and oil may be used as air outside the housing and low temperature fluid (outside air) which is -fluid outside the casing. In these cases, pumps are used as the inside fluid circulating means and the outside fluid circulating means. As means for actuating the pump, and the centrifugal fans 31 and 34, not only the electric motors 32 and 33 as in this embodiment but also the -internal combustion engine, water mill, or windmill may be used.

In this embodiment, the elect-ric heater 5 is used as the inside heater; however, there may be employed a fluid type heater core, in which waste heat of the internal combustion engine and heating parts is transmitted to the fluid such as cooling water, and the fluid is heat-exchanoed with the high temz)erature fluid (internal fluid) to heat the high- t emperature fluid. A plurality of plate fins 57 and 58 are used as radiating fins; however, as the radiatinq fin, a corrugating fin, a fine pin fin, a slit fin or a louver fin may be used.

A seventeenth embodiment in which a cooling apparatus Drovided with a heat exchanger is incorporated into an electronic equipment apparatus will be described with reference to FIGS. 56 to 61.

FIG. 56 is a view showing the ent-'re Constructic- of the elect-ronic apparatus.

An electronic apparatus 1 is a radic base station c-ff a mobile radlio telephone, such as a cc---,J-!e-Ss telenhcne, a car telenhone and the like, and includes a housinc 13 '-cr -i09- hermet-4cally housing electronic parts 11 and 12 therein, and a cooling apparatus (a cooler) 14 incorporated into the housing 13 to cool the elec--ronic parts 11 and 12, and the like.

The electronic part 11 is a heattlLng elemer-_ which per-forms a predetermined operation when electr4city is su-,,I-_l_Je-; thereto and cenerates heat (for example, a semiconduc-:or switc'"Inc element consti, tutinq a h1c' frequency switch.ina circuit incorporated into a trans-receiver) The elec-._-onic part 12 is a heatinc element which performs a Dredeter-mined operation when electr:_city is supplied thereto and generates heat (for examDle, a semiconductor amDlifving element such as a power transistor incorporated into a power amplifier).

The housing 1.3 for sealing the interior frcm the exterior, her-metica, I v, def ines a closed space 15 therein. This closed space 15 is secarated from outside comnle--elv hermet--'cally by means of a fluid separating plate or the like of a cooling apparatus 14 described later in order to prevent the performance of the electric parts 11 and 1-2 from being deteriorated due to the deiDosition of dust or water to the electronic carts 11, and '12.

he closed space _75 is Dartitioned into an electronic cart acco=odat-_'ng snace 1-6 for acco=,cdat_ng -:he elec':rcnic carts 1-1 and 12 therein and a hl-g.t-,z:emr)erat,,are--z-cie '-eat tra-s::er s::)ace 17 as an ins-4de Dassace inslde the cas"nc the flui-_4 Secaraz_na nlate of --ne ccoling az:)caratus 1-1 and t '- e cas.,-ng of -:he c3olng appara--us 14. 11-ie -f-Low path of --he '--"gh temcera-:ure-s_-de hea-_- transfer scace 17 _4S narrow on zhe u:wind -17.0- side, in order to minimize the depth size of the cooling apparatus 14, while the flow path area of the same space on the downwind side is wider. Further, the housing 13 forms a low temperature-side heat transfer space 18 as an outside passage outside the casing hermetically sealed-4 from the high -LemDerature-side heat transferspace 17 by the fluid separat-;;_na plate.

The cooling apparatus 14 includes a casing 20 provided integral with the housing 13, two upper centrifugal blowers 21 for generating an air flow of low-temperature air (external fluid, low-temperature fluid), two lower centrifuaal blowers 22 for generating an air flow of high-temperature air (external fluid, high temDerature fluid), an elect-ric heater 23 for maintainng an air temperature in the closed space 15 at a level not lower than a lower limit temperature (e.g., 0 C), a controller 24 for controlling the supply of electricity for the electric devices of the cooling apparatus 14, and a heat exchanger 25 for maintaining the air temperature in the closed space 15 at a level not higher than an upper limit temperature (e.g., 65 C), etc.

The casing 20 includes an outer wall plate 26 disnosed at the outermost side of the electronic apparatus 1, and a rear partitioning plate 27 for surrounding the high- t emperature-s ide heat transfer space 17. These outer wall.plate 26 an the rear partitioning plate 27 are secured to the hous'Lnq 13 ty bondinq, e.g., a spot weldina, or by using fastening means such as screws or bolts.

The two upper centrifugal blowers 21 include a centr]-fugal fan 31 for generating an air flow in the lowtemperature-side heat transfer space 18, an elect----:c motor 32 for rotat4na the cen-r'fugal 'an 31, -L. - L and a scroll casnc 33 for rotatably housing the centrifugal fan 31 therein.

The two lower centrifuaal blowers 22 include a centrifugal fan 34 for cenerat--na an air flow ';_n the high temperature-s.ide heat transfer space 17, an electric motor 35 for rotating the centrifugal fan 3'T, and a scroll casing 36 for rotatable housina the centrifugal 'Lan 34 therein.

The electric heater 23 is internal fluid heatinc means for heating air flowing through the high temperature-side heat transfer means 1-17 so that the temperature in the closed space is higher than the lower limit temperature since the performance of the electronic Darts (e.g., semiconductors) J! and 12 when the temperature in the closed space 15 is lower than the lower limit temDerature (Oc C).

The controller 24 is for controlling the elec,=ic devices such as the elect--ic motor 32, two lower cent--ifugal blowers 21, the electric motor 35 of two lower centrif,.iaal blowers 22, and the electric motor 23.

The controller 24 controls such tat two:p centrif:ugal blowers 2-1 and two lower --entrifucal blowers 22 onerate in a Hi mode (Ilarce a _J r a i. i o L::i " -, n rt a _1 r, m c, E! ': IM - 12 a--:r amount) when the temperature in the close--; s:ace 15 is hic'ner --nan the lower!_mit temneratu-re (e.g., C -,/, to turn OFF the elec,:ric heater 23. When tl-e tempera-ure in the closed -112- space 15 is lower than the lower limit (e.g., Oc C), the controller 24 turns OFF the electric motor 32 of two upper centrifugal blowers 21, the electric motor 35 of two lower centrifugal blowers 22 operates in H_J mode (large air amount) or the electric motor 35 of two lower centrifugal blowers 22 operates in Lo mode (small air amount) to turn OFF the electric heater 23.

The beat exchanger 25 provided with the cooling unit will be described in detail with reference to FIGS. 56 -.c 60.

FIG. 57A is a view showing the schematic construction of the cooling apparatus, FIG. 57B is a view showing the heat exchanger with cooling units disposed in plural stages, FIG. 58 is a view showing the detailed construction oil the coolirc:

unit, and FIGS. 59 and 60 are views showing the fluid separating plate for dividing the cooling unit into two portions.

The heat exchanger 25 includes a fluid separating plate 2 for hermetically separating high temperature air which is internal air (inside air) circulating in the housing 13 from low-temperature air which is external air (outside air, circulating outside the housing 13, and cooling units 3 mo,_,nted t 4 on the fluid separa;-ng plate 2 in plura7 (two) stages while being -in the state as to pass t.1-_-ouah the fluid separat-'na plate 2.

The fluid seDarating plate 2 forms one wall surface 'a mart. of the casing) of the housing 13 const. _Jt,,:t -4nc one wa-17 surface of the closed space 15, an interior of which is at h- -113- teriDerature, and one wall surface of the low temperature heat transfer 18, an interior of which is at low temperature. The Diate 2 is formed from a sheet made of a metal material which is suoer-4or in heat ccnductivity, such as aluminum, and brazed integral with the cooling unit 3 and the casing 20 so as to hermet-Lcal7v define the closed space 15 including tl,,e high temperat,.ire-s ide heat transfer soace 17 from --he extericr includ-ina t'ne low-temperature-side heat transfer svace.

The -fluid separating plate 2 is bored with a plu--a-1 _4 ±- v of elong-ated rectangular or oblong throuch-Ilicles '58 (for examr)le, wid--h is 1.7, mm and length is 16.0 mm) through which cooling tubes of the cooling unit 3 pass at predetermined intervals, as shown in FIG. 59. The fluid seiDarating plate 2 may be cl split plate (.',-n this embodiment, divided into two pieces), as shown in FIG. 60.

The cooiina unit 3 is a multiflow path type heat 4 exchanger assembled _n plural stages while being in a state as to be inclined at a prede--erm-4ned angle within the casilng 20, Wh4 and includes a pjUral4tV of COC14ng pipes 4 in ch a fluorocarbon type or freon type refrigerant is sealed, a nair of connec-z:ion PiDes 5 in commun-'cat-'on with the cooling tubes 4, and a Dluralit-; c-f heat transfer fins 6 mcun-ze,_J externally of the cooling tubes To bozh sides of the coc14;_nc unit 3 are connec-zed; the se,:)arati_-a clatc 2 and a side pla--e 37 2 5 which funct-= to fasten the fl-aid seDarat_ng plate 2 and the cas-'n-- 20 b%, -fasteninc meana and also f-unction to re-in-liforce --he m1uralit,; of coolinci -_,_,tes and the Dlaralit-y of hea-. t-ransfer fins 6. The cooling units 3 are disposed in plural stages (e.g., two stages) in a flowing direction of high-temperature air and low-temDerature air.

Cool 4 The plurality of Lng tubes 4 are formed from flat pipes having an elongated rectangular or oblong cross section (for example, width: 1.7 mm, and lenath: 16.0 mm), which is superior in heat conductivity., such as aluminum, copper or the like, which pass through through-holes 38 of the f lu id separating plate 2. The cooling unit 3 composed of these cooling tubes 4 comprises a ref-rigerant tdnk (a boiling portion) 7 on one side (lower side in FIG. 58) disposed on the high-temperature-air side from the fluid separating plate 2, and a vaporized refrigerant tank (a condensing portion) on the other side (upper side in FIG. 58) disposed on the low temDerature-air side from the fluid senarating plate 2. In this embodiment, the boiling portion 7 and the condensing portion 8 have 360 mm. in width (dimension in the width direction), 430 mm. in height, and 16 r-T. in thickness.

The connection pipe 5 includes a high-temperature-side tank 41 connected to the lower end of the plurality of cooling tubes 4 (boiling portion 7) and a low-temperature-side tank 42 connected to t.ne upper end of the olurali-!--y of cooling tubes 4 (condensing port 4 on 6), communicating the cooling tubes 4.

These hic-temoeratu-e-side and low--e-,Merature-side -anks 41 2 55 and 42 include a core plate provided on tte side of the ccol-4nc L-u--es 4 and a substantially U-shaped tank plate connected to tne core plate. Either hiah-temnerature-side tank 41 or the - 115- low-temperature-side tank 42 is provided with a single refrigerant sealing port (not shown) for sealing a refrigerant into tne cooling unit 3. The refrigerant is sealed into the cooling tubes 4 of the cooling unit 3 up to a height at which L L 4 a -quid level in cor-respondence with a pos-4-L4Lon of the fluid separatJLnc: plate 2, that is, to a height of the boiling portion 7. The refricerant is sealed after the heat. transfer fins 6 have been brazed to the cooling tubes 4. The high temzerature-side tank 47. need not be provided.

The heat trans"ffer fin 6 includes a heat receiving fin 6a interposed between the cooling tubes 4 ad-:,acent to each other on the high-temperature side (boiling portion 7) of the coolina unit 3, and a -radiating fin 6b interDosed between the cooling tubes 4 adjacent to each other on the low temperature side (condensing portion 8) of the cooling unit 3. The radiating fin 6 is a corrugat-ed fin formed into a wavy shape by alternate-7v pressing and bending a thin plate (for example, th'Lckness -is aDmroximatelv 0.02 to 0.50 mm) formed of metal material which is suDerior in heat conduct ivi ty, suc- as aluminum. That is, the outer wall surface of the coolinc tube 4 and the radiatina fin 6 are connected in a fused state.

The aeat receL%,inc; fins 6a are disposed below the -fluid separa-_ing plate 2. 7he "fin Ditch P! is, for exammle, 2.4 mmr, and tn -_ -f 'in width B!, is, for exam--Ie, 16 mm. The 1"in -P-1 is Dreferably, for examnle, in the range of 1.50 mm to 2.90 Tin, more preferablv, in --'-Ie rance of 2.00 mm to 2.50 mm. The radiat--'n-- f-'ns 6b are d-JI-snosed above the flulid seDaratina:_-a-r_-- e 2. The fin pitch P2 is, for example, 3.75 mm, and the fin width B2 is, for example, 16 mm. The f in Pitch P2is preferably, for example, in the range of 3.00 mm. to 4.50 mm, more preferably, in the range of 3,50 mm to 4.00 mm. That is, the cooling unit 3 has the fin pitch Pl of tte heat receiving fin 6a smaller than the fin pitch P2 of the radiating fin 6b by, for example, approximately 50% to 65%.

In the heat exchanger 25, the cool-inc units 3 are disposed in plural stages in a flow-Lnq direction of h-4gh temperature air and low-temperature air so that hiah temperature air (clean air in the housing 13) which circulates within the high-temperature-side heat transfer sr)ace 17 of the closed space 15 and low-temperature air (foul air outside the housing 13) which circulates within the low-temiDerature-side heat transfer space 18 flow in oppCS4 Lte direction with each other.

That is, in the heat exchanger 25 including the coo! J nq units 3 in plural stages, the right side portion of the lower end portion (boiling portion 7) of the cool';_nq tubes 4 of the second-stage cooling uni 3 is an inlet of the high- temperature air, and the left side portion of the lower end portion (boil-ing portion 7) of the cooling tubes 4 of the fi_rst-stage coolina unit 3 is an outlet of the high-temz)erature air.

Further, in the heat exchanger 25, the _7,ft side portion of the upper end portion (condensing portion 8' of the cooling tubes j 4 of the first-stage cooling unit 3 is an inlet of the hiq- temDerature air, and the right side po_rtion of the uDper end -117- port'-on (condensing portion 8) of the cooling tubes 4 of the seccnd-st;Qe coolinc unit 3 is an outlet of hich-temoerature air.

An oneration of the cooling apparatus 14 provided with the heat exchanger 25 in which the ccoling units 3 of this embodi-ment are disposed in plural stages so tha-L the high tem:Dera--,,ire air and low-temDerature air flow in opposite directions w-1.11 be descr-'bed here inafter trie-flv wl'th reference to FIGS. 57 and 58.

Wien the temiDerature in the closed space 15 in the housing 13 is higher than the lower limit temperature (e.g., 0- C), the electricity is supplied to the elecz=Jc motor 32 of two upper centrifuga'; blowers 21 and the elect-ric motor 35 of two lower centrifugal blowers 22, and the centrifugal fans 31 and 34 star-- to be onerated. In th-is way, a flow of h4ah temperature air (clean inside air not contain-inq foreign material such as dust or water) circulates in the closed space in --he housing 1-3. Further, a flow o-f low-temDerature air (outside air contain ing foreign material such as dust or water) circulates in the low-temr)erar-ure-side heat transfer s:Dace 1-8 cuzside the hcusinc 13.

in --he cocl';_na unit -7 mounteci while being Ln a sa-e as to pass thrcuch the f--,--,';_d separating plate 2 of the housinq 13, the _-efrizeran,: sealet into the cocl-inu tabes 4 of: t1-_= coo7 nc units 3 in:Iural s-,--;zces receilves heat z.-ansmi-_-ed]"rom t1lie high--empera-Lure air -:hrouql-, the heat rece.';_vina fins 6a and L's boileci and vaDorizec as snown in FIG. 57.'-. The vancr_'zed -'18- refrigerant becomes condensed and liquefied on the inner wall surface at the condensing portion 3 provided on the upper end of the cooling unit 3 exposed to the low temDerature air and being at a low temperature, and the condensed latent heat is transmitted to the low temperature air through the rad 4 ating fins 6b.

The refrigerant condensed and licuefied at the condensing portion 8 drops, due to its own weight, on the boiling portion 7 provided on the lower end side of the cooling unit 3 along the inner wall surface of the cooling unit 4, as shown in FIG. 57A. As described above, by repeating vaporization, condensation and liquefaction of the refrigerant sealed into the cooling tubes 4 of the cooling unit 3 alternat.ely, heat of the high-temperature air moves to the low temperature air. In this way, heat generated in the electronic parts 11 and 12 is radiated at the cooling units 3 in plural stages.

Thus, the electronic parts 11 and 12 can be cooled without the mixture of the high- temperature air (clean air within the housing 13) which circulates within the high temperature- side heat transfer space 17 of the closed spa-ce 15 and the low- teMDerature air (foul air outside the housing 13) which circulates within the low- temDerature-s ide heat transfer snace 18.

in the cooling unit 3 of this embodiment-, since the fin pitch P! of the heat receiving fins 6a is smaller than the fin pitch P2 of the radiating fins 61::, the heat exchancing _119- effective area of the boiling portion 7 projecting downward from the fluid separatinq plate 2 (projecting into the housing 13) 41-s smaller than that of the condensing portion 8 projecting unward]"_-om the fluid separating plate 2 (-__roecting outside the housina 13), out of the plurality of the cooling tubes A, however, the boiling portion 7 can improve the heat exchanging nerformance as muc! as a small amount of t1ne fin pitch, and the heat exc-ar.c:_"ng performance is no-- lowered even i:" the heat exchanging effective area of the bo-J"lina portion 7 is small.

An effect of this embodiment will be described.

Since the hiah-temiDerature side in the cooling unit 3 of this embodiment is hermetically sealed bv the housing 13 (fluid se-arating plate 2), the fin pitch Pi of the heat receiving fins 6a provided on tne cooling tubes 4 constituting the boiling portion 7 where no clogging occurs is set smaller than the _f_4n pi-:c-) _712 of the radiating f__ris 6b provided on the cooling tubes 4 constituting the condensing portion 8 exposed to outside air ccntaining fore.Lgn material such as dust or water.

Tn this way, as compared with the case where the 'in pi--c- or -he high-temperature side (inside air s4L-de, of the fluid separating plate 2 is the same as that on the low temperat-ure side (=:s4L--e air side), the f--'n pitch PI of the 7'er than tne -_n zi-ch P2 of the boi7na -.',cr-_4cn 7 is se-: sma.__ CC07 2_5 condensina zcrtion 8 to Lrmrove t'-e -Ing performance of 7 hign-temiDerature air. Further, -.'-,e dimension of" --'.ne heat receivinz f4Lns 6a can be reduced to be shorter than t-at -_;L20- of the radiating fins 6b by the amount in which the fin pitch 4 Pl is reduced. In this way, the vertical dimension (radLating effective area) of the boiling portion 7 of the plurality of coolinc tubes 4 can be reduced, and the whole of the cooling unit 3 and cooling apparatus 14 can be downsized.

The features of the heat exchangers in which the cooling units 3 are disposed in plural stages in a flowing direction of high-temperature air and low-temperature air will be described hereinafter with reference to FIGS. 61A and 61B.

FIGS. 61A and 61B are respectively schematic views showing the temperature distribution in the direction of flow passage of air and the temperature distribution in the direction of flow passage of refrigerant in the case where the cooling unit(s) 3 are of a single stage (one stage) and plural stages (two stages). In the schematic views, the axis of ordinates indicates the temperature (the lower, the higher temoerature) and the axis of absc-issae indicates the flow direction of the fluid (air).

In the case of the heat exchanger in which the cooling unit 3 is of the single"stage (one stage), as shown in 77G.

51A, the high-temperature air flows from the right side (shown) of the lower stace cooling unit (boiling portion 7). After -he I L temneratu--e of the high-temperature air lowers as the heat is radiated to the upper stage cooling unit (condensina portion 8), the hiah-temperature air (cooled hicn-ten-nerature air) flows ou-z left side (shown) of the coolinq unit 3. Fur--her, in the case of" the heat exchanger in which the cooling unit 3 is -121- of the single stage (one stage), as shown in FIG. 61A, the low temperature air flows in from the left side (shown) of the upper stage cooling unit (condensing portion 8), and the temQerature of the nich-temperature air rises as the heat is received from the cooling unit, and the hich-temperature air flows out r4Laht side (shown) of the cool-ing unit 3.

t1 temperature difference between inlet -ssuming that a air an(:i cutIet air of the condensing portion 8 of the cooling unit 3 iS _,",T!, since a heat exchanging medium heat-exchanged with the refrigerant sealed into the cooling unit 3 is air, the low- temDerature air is rapidly heated by the radiating fins 6b of the cooling unit 3, and the temperature of the low temoerature air rapidly rises at the inlet; however the low temcerature air becomes in a saturated state, so that the temperature difference LT (cooling performance) does not become so larce.

4 on the other hand, -1-n the case of the heat exchanuer 25 in which tne cooling anits 3 are disnosed in clural stages (as in the seventeenth embodi-ment), as shown in FIG. 61B, heat excltanaLna between the.-efricerant sealed into the cccllina unit 3 and a:'_r can be perf"crmed at least in two stages in -the flowing ci--rection cf the air. 7--t this time, since there is a +.-emnera-_'.:re d_'_ference (a temperature difference between rad_4at_-'nc -'--'ns, a temcera-:ure d',_fference between heat recevna f4p S aS - L _4c-ate-_; '--v brcken 1'nes betwee- the rer4aeran sealea; in'o the Ifirst stage coo!_4ng unit 3 and the re-;"riaerant sealed Into the seconc! stace cooina unit 3, the temnerat-.:re -122- further rises in the vicinity of the inlet of the second stage cooling unit 3 after the low-temperature air has beena saturated temperature in the middle of the condensing portion 8 of the first stage cooling unit 3, whereas the temDerature further lowers in the vicinity of the inlet of the first stage cooling unit 3 after the high-temperature has been a saturated temDerature in the middle of the boiling portion 7 of the second stage cooling unit 3, as shown in FIG. 61B.

Accordingly, since a temperature difference _1^\T2 in the case of this embodiment (the heat exchancer 25 with the cooling units 3 disposed multistage) can be set larger than the temmerature difference Al in the case of the heat exchanger with a single stage cooling unit 3, as shown in FIGS. 61A and 61B, tha heat of the high-temperature air can be radiated to low- temDerature air so that the cooling performance of the high -temperature air can be improved. In this way, since the cooling effect of the electronic parts 11 and 12 can be imDroved, the electronic parts 11 and 12 can operate stabiv.

Further, in this embodiment, as compared with the radiatinc performance (cooling performance) equal to that of prior art, the heat exchanging effective area (radia-Lina 27 effective area) of the cooling unit 3 can be reduced, and therefore; the whole of the cooling apparatus 14 provided with the ccmpac-:

heat excnancer 25 can be downsized.

The heat exchanger 25 with the Cool-ing units 3 in plural staces is disposed so that the high-temperature air and the low- temDerature air flow in opposite aJ_Jrections wJ_t, eacn -123- other. Accordingly, since there can be effectively provided a -emDerature difference between the temperature (radiating fin tem-,erature, heat receiving fin temperature) of the refrigerant sealed into the first. ccolinc unit 3 and the temmerature (radiating -'in temnerature, heat receivinq fin temperature) of the re-'ricerant sealed into the second cooling unit 3, it is possible to sequentially ef-ficiently increase and decrease the emDerature of the low-temnerature air and the hich-temiDera-ture air by using the refrigerant having a temperature difference.

in this way, it is possitle to further improve the cooling performance and to dcwnsize the whole of the cooling apparatus 24.

In this embodiment, the coolinq units 3 in two stages are described; however, if a temperature difference between the air inlet and air outlet of the boiling portion 7 and the condensing portion 8 of the heat exchanger 25 needs to be larger, plural staces being equal to or -nore than three stages can be employed, an operation and effect of which is similar, and a description thereof will be omitted.

An eighteenth embodiment of the present invention will be described with reference to FIGS. 62 to 66. FIGS. 62 to 64 are views showina the detaile(i construction of the cooling apparatus incorr)orated into the electroni-- apparatus, FIG. 65 is a view shcwinc the de-!--ailed constr,-:ction of the cccling unit, and FIG. 66 -is a view showinc a schematic const-ru----cn of the heat exchancer i- which cool-nq ur--ts are dis:Dosec; in plural staces -124- The cooling units 3 constituting the heat exchanger 25 according to this embodiment are mounted in plural stages (three stages) while being in a state inclined at a predetermined angle within the casing, which is divided into two pieces, i.e., a hightemperature- side heat exchanger (inside air-side heat exchanger) 3a in which a plurality of cooling tubes 4a constitute a boiling port-Lon 7 and a low temperature-side heat exchanger (outside air-side heat exchanger) 3b in which a plurality of cooling tubes 4b constitute a condensing portion 6. These high temperature-side and low-temperature-side heat exchangers 3a and 3b are connected by two refrigerant circulating first and second connection pipes 9a and 9b.

A casing 20 includes an outer wall plate 26 and a rear-side dividing plate 27, similar to the seventeenth embodiment. In the central portion of the outer wall plate 26 is opened a single square low-temperature-side suction port 26a for sucking the low-temperature air (foul outside air containing foreign material such as dust or water) into a low temperature- side heat transfer space 18 from outside. On the uuDer side of the outer wall plate 26 are opened two squa-re low- temTDerature-side discharge por-. 26h for discharging low tem:)eratu.-e-air to outside from an uDner centrif'uaal blower 21.

on the upper side of the rear si-'e divLdinq plate 27 is opened a single square high-temperature-side su---.--:on port 27a Zor sucking high-temperature-air (clean inside air not containing -fforeign material such as dust. c-r wa,:erl into a high -125- temDerature-side heat transfer space 17 from an electronic part accommodating space 16. To the lower side of the rear side partition plate 27 are Joined, by means of a spot welding or the like, a duct 27b for introducing cooled high-temperature air to an electronic part 11 from one lower side centr-ifuaal blower 22 and a duct 27c for introducing cooled high temperature air to an electronic part 12 from the other lower side centrifugal blower 22. The ducts 27b and 27c are connected integral with a scroll casing 36 for two lower side centrifugal blowers 22.

7he high-temperature-side heat exchanger 3a includes a pluralitv of coolinc tubes 4a, a hah-temDerature-side upper end tank 41a, a high-temperature-side lower end tank 42a, a C0014 heat receiving fin 6a interposed between the _ng tubes 4a adjacent to each other, a side plate 37a, and the like. Since the high- temperature- side heat exchanger 3a is disposed within the high- temperature-side heat transfer space 17 sealed from the outside by the housing 13, there is no possibility that the hightemperature-side heat exchanger 3a is exposed to outside air containing foreign material such as dust or water.

71ae -side heat excnanger 3b includes a . low-temperature pluraliv; of cooling tubes 4b, a low-temperature-side upper end tank 41t, a low-temzerature-sia;e lower end tank 42b, a radiatfnc fin 6b in--err)osed between.--he cooling tuties 4b S 4 2 5 adjacent to each other, a _Lde plate 37b, and tle -1--ke. The 7ow- temzerat'ure-side heat exchanger 3b is disposed sc as to!De L Dositionea; on substantialiv the same D-lane as the-tlah - 126- temperature-side heat exchanger 3a within the lowtemperature-side heat transfer space 18 exposed to outside air containing foreign material such as dust or water. The lowtemoerature-side lower end tank 42b may be JLnclined such that is poS4t4 the second connection pipe 9b side - -Loned downward.

In -the cooling unit 3 according to this embodiment, the f in pitch P 1 (f or example, 1 - 5 0 mm. to 2. 9 0 mm, more pre-lerahlv, 2.00 mm to 2.50 =, and 2.40 mm. in this embodiment) of the heat receiving fin 6a provided on the h igh- temperature- side heat exchanger 3a is made smaller than the fin pitch P2 -for example, 3.00 mm. to 4.00 mm, more preferably, 3.50 mm to 4.00 mm., and 3.75 mm in this embodiment) of the fin pitch P2 of the radiating fin 6 of the low-temperature-side heat exchanger 3b.

That is,-the cooling unit 3 has the fin pitch P1 of the heat receiving fin 6a smaller than the fin pitch P2 of the radiating fin 6b by, for example, approximately 50% to 65%.

The first connection pipe 9a is a metallic pipe made of the same metal material as that of the cooling tube 4 and is formed to have a circular cross section. The first connection 2 C pipe 9a communicates a high-temperature-side upper end tank 41a provided on the upper end of the boiling pcr-.--:on 7 with a lower temDerature-side upper end tank provided on the upper end of the condensing portion 8. The first connection DiiDe 9a is hich-to-low temperature guide means for:.ntroducna a vapori, zed 2_5 ref.-icerant boiled and vaDorized by the bcilirg port'-on 7 to the condensing portion 8.

The second connection pipe 9b is a- metal-lic p1pe made -127- of the same metal material as that of the first connection pipe 9a and is formed to have a circular cross section. The second connection pipe 9b co=.unicates a low-t-emperature-side lower end tank 42b provided, on the lower end of the condensing portion 8 with a hJLgh-temperature-side lower end tank provided on the lower end of the boiling po--ticn 8. The second connection pipe 9b is low-to-high temperature guide means f1for introducing a liquid refrigerant condensed and liquefied by the condensing portion 8 to the boiling portion 7.

An effect of the eichteenth embodiment of the present invention will be described.

In this embodiment, as compared with the case where the fin pitch on the high-temperature side 41 ns ide air-s ide) of the fluid separating plate 2 is the same as that on the low temperature side (outside air side), the fin pitch P! of -he high temperature-side heat exchanger 3a 41S set smaller than the fin pitch P2 of the low--Lemperatu--e-side heat exchanger 3b to imorove the cooling performance of high-temperatu-re ai--, thus downsizing the whole of the cooling unit 3 and cooling apparatus 14.

This embodi:-nent is provided with -he cooling apparatus 14)rovide,_-; with the heat exchanaer 25 in which the cool'Ma units 3 hav';_ng the boiling pcr-:J;_on 7 and the condensing:)o-----4o-.I 8 annulariv connected bv two first and beccnd connection n4Des 9a, 9b are -_isoosed in D-lural staces in the flow4,_ng direction of the a-'r. With this ccnst_4tution, a c_'rcuiati-a flow of the refriaerant is fc=ed within the cool'nc: urit 3 to pre-,.ren- a collision between the vaporized refrigerant (boiled vapor) and the liquid refrigerant (condensed liquid). Thus, the radiatingperfo=ance (cooling performance) of a single cooling unit 3 can be further improved as compared with the seventeenth embodiment. By disposing the cooling units 3 in plural stages as described, the radiating performance (cooling performance) of the heat exchanger 25 can be further improved as compared with the seventeenth embodiment.

A nineteenth embodiment of the present invention will be described with reference to FIG. 67.

FIG. 67 shows the detailed construction of the cooling unit.

The cooling units 3 constituting the heat exchanger 25 according to this embodiment are mounted multistage-wise (three stages) in a state inclined at a predetermined angle within the casing, which is divided into two, i.e., a high temperature-side heat exchanger (inside air side heat exchanger) 3a constituting a boiling portion 7 and a low temperature-side heat exchanger (outside air side heat exchanger) 3b constituting a condensing portion 6, these hich temperature-side and low temperature-side heat exchangers 3a, 3b being connected by first and second connection pipes 9a, 01b.

In the cooling unit 3 according to -this embodiment, the high-temperature-side heat exchanaer 3a and the low temDerature-side heat exchanger 3b are disposed to be dev'a-ed from each other on substantially the same plane and on h)oth sides (left and right sides in the fioure) in the width -129- direction, as comvarea with the eighteenth embodiment.

Further, refrigerant circulating first and second connection pipes 9a and 9b for annularly connecting the high temperature-side heat exchanger 3a and the low temperature-side heat exchanger 3b are disncsed on the position-deviat-ed portions 51 and 52.

The first connection pipe 9a is a metallic p4;_De and commun-4cates a high-temperature-side upper end tank 41a provided on the upper end of the high - t emperature-s ide heat exchanger 3a (boiling portion 7) with a low-temperature-side upper end tank 41b provided on the upper end of the low temperature-side heat exchanger 3b (condensing portion 8) to introduce a vaporized refrigerant boiled and vaporized in the boiling portion 7 to the condensing portion S. The second connection pipe 9b is a metallic pipe and communicates a low temr)erature-side lower end tank 42b provided on the lower end of the low-temiDerature-side heat exchancer 3b with a high temoeratu--e-side lower end tank 42a provided on the lower end of the high-temperature-side heat exchanger 3a to introduce a liquid refrigerant condensed and liauefied in the condensing - 4 por.__on 8 to the bcilinc portion 7.

An effect of the nineteenth emhodiment will be descril---ed.

-n this embodi-men-zi, the hia-te=erature-si3e heat excianaer 3a and the low- temiDerature-s ide heat exchancer 3b are disDosed to be deviated from eac, other on substantialiv the same -,-Iane and on both S 4 des in the width direction, and -.'i,.e -130- refrigerant circulating first and second connection pipes 9a and 9b for connecting the high-temperature-side heat exchanger 3a and the low-temperature-side heat exchanger 3b are disposed on the position-deviated portions 51 and 52. In this way, as compared with the eighteenth embodiment in which the first and second connection pipes 9a and 9b are provided projectingly on both sides (left and right sides in the figure) in the width direction of the cooling unit 3, the side dimension can be reduced by a portion of the pipe projecting portion and the first connection pipe 9a which is a dead space, thus further downsizing the whole of the cooling apparatus 14 provided with a compact cooling unit 3.

Modifications of the seventeenth to nineteenth embodiment will be described.

The cooling apparatus 14 provided with the heat exchanger device 21 according to these embodiments is utilized in the case where the heating elements such as the electronic parts 11 and 12 need be accommodated in the closed space. The case where the heating elements need be accommodated in the closed space includes the case where heatina elements are used under the severe environmental condition containinc, for example, oil, water, iron powder, corrosive gases, etc., the case where inactive gases (helium gas, argon gas, etc.) are used to prevent arcing or oxidation of contacts at the time of electric intermittence, or the case where gases ha=ful to the human body (for example, such as hydrogen -'-7uor.-;:_de deccmnosed from fluorocarbon) are prevented from leaking outside.

-131- In these embodiments, a multiflcw pass typeheat exchanger having corrugating fin tubs is used as the cooling unit- 3, the high temperature-side heat exchanqer 3a and the low temperature-side heat exchanger 3h; however, a heat exchanger having plate fin tubes, a heat exchanger having fine pln-f.:Ln tubes, a heat exchanger of a serpentine type having flat tubes bent in a zigzag manner, and a heat exchanger of a I-.,_-awn-cup type having a mluralit-y of laminated cooling tubes in which two pressed plates are connected to eaic, other, may be used as the cooling unit 3, the high temperature-side heat exchanger 3a and the low temperature-side heat exchanger 3b. Slit fins or louver fins may be used as the heat receiving fin 6a or the radiating fin 6b.

-In these embodiments, h-Lch-t-emperature gas such as high-temperature air, heated by heating elements such as the electronic parts 11 and 12 is used as air in the hcus-ing 131 and high-temDerature fluid as fluid in the casing (inside a-4 r however, cooling water for cooling the heating elements such as the electronic parts 11 and 12 and hich-temr)erature liqui(: such as oil (including working oil and lubricating o-4-7) may be used as a higt-temperature fluid. In the same manner, not only low temperature gas such as low temperature air but aisc low temDerature liauid such as water and o-J-7 may be use,-; as air cuts- the hcusinc and low zemnerature fluid (ou:s_J1r_;e air) 2 C5 whic- is fluid outside the casina 7- these cases, Du.mcs are used as tne ins ide fluid circulat ng m e a n s a nd t h e cu t s 16 e fluid circulating means. As means fcr ac-:uating tie cumc, and -132- the centrifugal fans 31 and 34, not only the electric motors 32 and 33 as in these embodiments but also the internal combustion engine, water mill, or windmill may be used.

A twentieth embodiment of the present invention will be described.

FIGS. 68 to 77 illustrate the twentieth embodiment of the present invention, of which FIG. 68 is a diagram showing the entire structure of an electronic apparatus, FIG. 69 is a diagram showing a structure of a cooling apparatus embodying the present invention specifically, FIG. 70 is a d 4 agram showing an upper structure of the cooling apparatus, and FIG.

71 is a diagram showing a lower structure of the cooling apparatus.

-An electronic apparatus 1 is an apparatus of a radio base station of a mobile radio telephone such as a cordless telephone or a car telephone. The electronic apparatus 11 includes a housing 13 which receives therein electronic parts 11 and 12 in a hermetically sealed state and a cooling apparatus (cooler) 14 mounted within the housing 13 to cool the electronic parts 11 and 12.

The electronic part 11 is a heat generating element, e.c., a semiconductor switching element constituting a hich incorporated in a trans- I -frequency switching circuit receiver, which performs a predetermined operation when an 2 electric current is supplied thereto and which generates he-=t.

The elect-ronic part 12 is a heat generating element, e.g., a semiconductor amplifier element such as a power trans4Lsto- -133incorporated in a power amDlif-Jer, which performs a predeter mined operation when an electric current is supplied thereto and which generates heat.

The housing 13, an interior of which is hermeticallv sealed from the exterior, has a closed sDace 15 formed in the interior thereof. In order to prevent deterioration in performance of the electronic parts 11 and 12 due to depcsition of a foreign material such as dust or water thereon, the closed siDace 15 is hermetically sealed completely from the exterior by t4ng means of a fluid separa.L plate provided in the cooling apparatus 14 which will be described later.

The sealed space 15 is partitioned, by both fluid separating plate and casing of the cooling apparatus 14, into an elect-ronic parts accommodating space 16 for accommodating the electronic parts 11 and 12 and a high-temperature-side heat transfer space (first heat transfer space) 17 which serves as an inside passage. In the high-temperature-side heat transfer space 17, the flow path area on the upwind side is narrow to decrease the depth of the cooling apparatus 14, and the is W4 downward side - J-der in flow path area than the upwind side.

With the --Fluid separating plate, the housing 13 further forms a low-temoerature-side heat t_rans:ffer space, which is a second heat transfer space, one heat transfer sDace, as an outside d passage partitioned hermetically from the nigh-tenperature-sl e heat transfer szace 17.

Next, the C007 ing aDzaratus 14 will be desc-Jbed Delow I.

with reference to FIGS. 68 to 74. 7TC-S. 72 and are d_Jaqrams each illustrating a structure of the cooling apparatus14 specifically.

The cooling apparatus 14 is a cooler for cooling the electronic parts 11 and 12 using semiconductors as heat generating elements.

Cool 4 The Mg apparatus 14 includes a cabinet 2 intearal with the housing 13, a heat exchancer 3 for maintaininq the air temperature in the closed space 15 at a level not higher than an upper-limit temperature (e.g., 65cC), two high temperature-side centrifugal blowers 4 for compulsorily circulating a high-temperature air (high-temperature fluid) which is the inside air, two low-temperature-side centrifugal blowers 5 for compulsorily circulating a low-temperature air (low-temperature fluid) which is outside air, an electric heater 6 for maintaining the air temperature in the closed space 15 at a level not lower than a lower-limit- temperature (e.g., O=C), and a controller 7 for controlling the supply of electric power to the electric devices used in the cooling apparatus 14.

The cabinet 2 includes a door plate 21 disposed on the outermost side of the electronic apparatus 1, a front part 4 -Jon plate (front plate) 22 attached to the back of the door plate 21, and a rear partition plate (rear plate) 23 which surrounds the high-temperature-side heat transfer space!7/. These parts are fixed to the housing 13 by bonding such as a spot welding or by using fastening means such as screws or bolts. on the upper end side of the cabinet 2 is detachaLly mounted a top fan -135cover 8 which covers the two low-temperature-side centrifugal blowers 5, while on the lower end side of the cabinet 2 is detactably mounted a bottom fan cover 9 which covers the two higt-temperature-side centrifugal blowers 4.

In the central portion of the door plate 21 and the front partition plate 22, as shown in FIGS. 69 and 72, there is formed a single rec-tanculiar low-temperature-side suction port 21a for sucking a lcw-temperature air (foul outside air containinq a foreign material such as dust or moisture) into io the -1low-temDerature-side heat transfer space 18 from the exterior. In the door plate 21 and the top cover 8, as shown in FIGS. 69 and 74, there are fo=ed two square low temperature-side discharge ports 21b for discharging the low-temr)erature air to the exterior from the two low temDerature-side centrifugal blowers 5.

To the two square low-temperature-side discharge ports 21b are attached droplets entry preventing means such as plural louvers 24 or mesh 24 to make it difficult for droplets such as rain water to enter the two lowtempera ture-side centrifugal 2C blowers 5 from the exterior. To the rear side of the upper end t 4 ocr _on of the door olate 21 are fixed fan cases of the centrizl'uaal blowers 5 through packing 21c by fastening means 21d such as screws and washers.

To the top plate portion of the front partit_40n plate G 70 2, as sr,.,cwn in F-I /, are f _Jxedi the fan cases of the centri-lucal blowers through packing 22a by fastening means 22b such as screws. --c tl-)e bottom plate portion of the --Front -136- partition plate 22, as shown in FIG. 71, are fixed fan cases of the two high-temperature-side centrifugal blowers 4 through a packing 22c by fastening means 22d such as screws. on the upper portion side of the rear partition plate S4 23, as shown in FIGS. 69 and 75, there is form e,-4 a Lngle rectangular high-temperature-side suction port 231 for sucking a high -temperature air (clean inside air not containing a for eign material such as dust or moisture) into the high temperature- side heat transfer space 17 from the electronic parts accommodating. space 16. To the lower portion side of the rear partition plate 23 is connected a duct 23b for introducing the inside air after cooled to the electronic part 11 from one high-temperature-side centrifugal blower 4 and _J s also connect6d a duct 23c for introducing the inside air after cooled to the electronic parts 12 from the other high tempera ture-s ide centrifugal blower 4, by a spot welding or the like. The ducts 231>' a'rid-4 23c are respectively connected integrally to the two centrifugal blowers 4. As shown in FIG.

71, the rear partition plate 23 is frixed to the bottom of the front partition plate 22 by fastening means 23d such as screws.

As shown in FIGS. 68 to 70, the ton --fan cover 8 has, in its top plate portion, suction ports 24a for suckinq coo'L air into the interior from the closed space 15 and also has, in its rear portion, discharge ports 24b for discharging cool air into the closed space 15 from the interior. The ton fan cover 9 is fixed to the rear partition plate 23 by fastening means 24c S 4 such as screws and is mounted detachalDiv to the body _Lde tdoor -137- plate 21, front partition plate 22, rear partition E;late 23) of the cabinet 2.

As shown in FIGS. 68, 69 and 71, the bottom -fan cover 9 has, in its bottom portion, suction ports (not shown) for sucking cool air into the interior from the closed space 15 and also has, in its rear portion, discharge ports 25b for discharging cool air into the closed space 15 from the interior. The bottom fan cover 9 is fixed to the front partition plate 22 by fastening means 25c such as screws and is mounted detachably to the body side (door plate 21, front partition plate 22, rear partition plate 23) of the cabinet 2.

Further, the bottom fan cover 9 fixes a support stand 26 by fastening means 25d such as screws. The support stand 26 fixes the controller 7 by clamping means 26a such as bolts and nuts.

Next, the heat exchanger 3 will be described below in detail with reference to FIGS. 68, 69, 74 and 75. FIG. 74 is a diagram stowing a structure of the cooling apparatus specificallv, and FIG. 75 is a diagram showing a structure of the cooling apparatus schematically.

The heat exchanger 3 includes a fluid separating plate 13a for ser)aratinc the high-temperature air as the inside air circulat.J;= insJLde the housing 13 and the low-temperature air as the outside air cirCulating outside the housing hermet ica!1, v -From eacn other, and plural (three L stages of cooling units 30 which are mounted to the fluid separating plate 13a wn.L."

passing through the same plate.

The fluid separating plate 13a, which -forms one wall -138- surface (a portion) of the housing 13, constitutes one wall surface of the closed space 15, an interlor of which is at high temperature, and one wall surface of the low-temperature-side heat transfer space 18, an interior of which is at low temperature. For example, the fluid separating plate 13a is constituted bv a thin plate of a metallic material wh 4 _ch is superior in heat conductivity such as alumin= and is soldered integrally with the cooling units 30 and the cabinet 2 so as to hermetically partition between the closed space 15 includLnq the high-temperature-side heat transfer space 17 and the exterior including the low-temperature-side heat transfer space 18. in the fluid separating plate are formed at predetermined intervals a plurality of elongated, rectangular or o'--lcnc through-holes through which connection pines in the cooling units pass, which will be described later. The fluid separating plate 13a may be a split plate (e.g., two-divided plate).

The cooling units 3 are mounted in plural (three) stages while being inclinedly by a predetermined angle within the cabinet 2 and are each divided into a hicl--temoerature-side heat exchanger portion (inside airS 4 de heat exchanger portion) 3a, an interior of which is filled with a --fluorocarbcn-type or creon-tvDe reF-icerant and a low-temperature-side heat por-4on exchancer portion (outside air-side heat excanger 3b.

The high- and low--Lemperature-side heat exc_,._anger portions 3a and 3b are interconnected throuah two ffirst and secont I connection pipes 3c and 3d for refricerant c1rculation.

-139- The high-temperature-side heat exchanger portion 3a is a multiflcw path type heat exchanger portion (inside heat exchanger portion) which includes a plurality of cooling tubes 27a, a high-temperature-side top tank 28a, a high temDerature-side bottom tank 29a, and heat rece-ivina fins 30a interposed between adjacent cooling tubes 27a. To both sides of t'ne hich-temiDerature-side heat exctanger portion 3a are attached side plates 3e which function to fix the heat exchanger portion 3a to the fluid separating plate 13a and the cabinet 2 bv fastening means and also function to reinforce the plural cooling tubes 27a and plural heat receiving fins 30a.

Since the hig-temperature-side heat exchanger port. -4on 3a is -he high-temperature-side heat transfer space 17 disposed in t which i! sealed hermetically from the exterior by the housing 13, there is no possibility that the heat exchanger portion 3a is exnosed to the outside air containing a foreign material such as dust or moisture.

The plural cooling tubes 27a are formed into 'Itlat- tubes having an elongated rectangular (e.g., 1.7 mm. wide, 16.0 mm long) or oblong cross sectLon and is made of a metal material which superior in heat conductivity such as, for examp'Le, aluminum or copper. The hLah-temperav-:re-side heat exchanger Qortion 3a includina tne cooling tubes 27a is const-4tuted as a liauid refrigerant tank (boiling po--tion) X where-in the sea-led refrigerant is boiled and vapor'-zed tv feceiv-inc heat f--= the hiah-temnerature air.

The hic.-temnerat-ure--=-'de toD tank 28a and bott= tank 2-3a are each commosed of a core plate provided on the side of the cooling tubes 27a and a generally inverted U-shaped tank plate connected to the core plate. One of the high-temperature-side top tank 28a and bottom tank 29a is provided with only one refrigerant inlet (not shown) for sealing the refrigerant into the cooling tank 30. The refrigerant is sealed into each of the cooling tubes 27a of the high-temperature-s--de heat exchanger portion 3a up to a liquid level apprcxL-,iately corresponding to the upper end of the tubes 27a, that JLs, up to the top of the boiling portion X. The re-frigerant is sealed into the tubes 27a after the heat receiv4Lng fins 30a are b.-azed to the tubes 27a.

The heat receiving fins 30a are corrugated fins.-Iformed by pressing and bending alternately into a wavy shape from a -'5 thin plate (e.g., approximately 0.02 - 0.50 ram thick) formed of a metallic material which is superior in heat conductivity such as aluminum for example. The fins 3Ca are soldered to the flat outer wall surfaces of the cooling tubes 27a. Thus, the outer wall surfaces of the tubes 27a and the heat receiving fins 30a 2'0 are connected together in a fused state.

The low-temmerature-side heat exchanger portion 3b is a multiflow path type heat exchanger por-ziion (inside heat exc.l-ancer portion) including a plura'-ity of cooling tubes 27b, a -1ow-temDerature-side top tank 2E'---, a low-temperatare-side 2 bottom tank 29b, heat radiating L-ns 30-1 interoose,_4 between adjacent cooling tubes 27b, and s_'cie plates 3-ff. 7he heat exchanger portion 3b is disposed so as to he positioned -141substantially on the same plane as the high-temperature-side heat exchanger portion 3a within the low- temperature-side heat transfer space 18 which is exposed to the outside air containing a foreLgn material such as dust or moisture.

* The plural cooling tubes 27b are formed in the same shane as the cooling tubes 27a. The lcw-temperature-s4Lde heat exchanger portion 3b including the cooling tubes 27b is constituted as a vaporized refrigerant tank (condensing portion) Y wherein the heat of the refrigerant vapor which has been boiled in the bo il 4 na portion X is released to the low-temzerature air to condense the vaporized refrigerant.

In the same manner as the high - temperature- side top and bottom tanks 28a and 29a, the low-temperature-side tor- and bottom tanks 28b,29b are each constituted by a core plate and a generally inverted U-shaped tank plate. The low temoerature-s-ide bottom tank 29b ma,,, be inclined such that the second connection pipe 3d side is positioned downward.

The heat radiating fins 30 are corrugated fins formed in the same shape as the heat receiving f ins 30a and are soldered to the flat outer wall surfaces of the coolinc --ubes 27b. Thus, the outer wall surfaces of the cooling tubes 27b and the heat radiating fins 30b are connected together in a fused state.

The first connection Pipe 3c -Ls a metallic pipe f---=ed 2 _5 -to tave a circular cross section by using the same metallic 4 ma':er-al as that of the cooling tubes 27a and 27b. The -ff-'--st.

ccnnec-:ion 131r)e 3c cc=unicates be--ween the hiah- -142temperature-side top tank 28a, located at the upper end of the boiling portion X and the low-temperature-side top tank 28b located at the upper end of the condensing portion Y. The first connection pipe 3c functions as high-to-low temperature guide means for introducing the vapor'-zed refrigerant which has been boiled in the boiling portion X to the condensing portion Y.

The second connection pipe 3d is a me-t-allic pipe -formed to have a circular cross section by using the same metallic mater-Lal as that of the first connection D4LDe 3c. The second connection pipe 3d communicates between the low temperature-s]-de bottom tank 29b located at the lower end of the cOndensing portion Y and the high-temperature-side bottom tank 29a located at the lower end of the boiling portion X.

The second connection pipe 3d functions as low-to-high temperature guide means for introducing the!-;_quid refrigerant liquid which has been condensed in the condensing portion Y to the hoiling portion X.

The high-temperature-side centrifugal blowers 4 will be described in detail with reference to FIGS. 68, 69 and 71.

The two high- temperature-side centrifugal blowers 4 are mounted below the heat exchanger 3 and are accommodated between the bottom fan cover 9 and the lower end portion of the cabinet 2. The centrifugal blowers 4 are eac,,i provided with a 2 _5 centr-'fugai fan 31 for comoulsorlilv circulating the high-temperature air into the h_4gt-te_mDeratu_-e-side heat transfer space 17, a drive motor 32 for rotatina the -143centrifugal fan 31, and a fan case 33 which receives therein the centrifugal fan 31 rotatably.

The centrifugal fan 31 includes a plurality of blades and a disc-shaped support plate 34 for supporting the blades.

The support plate 34 is fixed onto an output shaft 35 of the fan 31.

The drive motor 32 is fixed by fitting a heat transfe-r accelerating plate 37 or. the outer periphery of a side plate 36 which is positioned closest to the centrifugal fan 31. At the lower end portion of the drive motor 32, a cooling fan 38 for blowing the atmospheric air (hiah-temperature air) to the dr-Lve motor 32 to cool the motor is mounted on the outnut shaft 35.

The fan case 33 forms a vertical compulsory circula-_-Lon flow path 39 in the interior thereof. The fan case 33 is provided with a fluid suction port 33a for sucking the high-temperature air into the compulsory circulation flow path 39, a fluid discharge port _33b which is open toward the t 4 electronic parts acco=odating space 16, and a fan moun ing opening 33c fo=ed in the bottom plate portion, the opening 33c having a diameter larger than the outside diameter of the centrifugal fan 31.

SUC,Z 4 The fluid -Lon port 33a is fo=ed in a bellmouth portion 40 of the top plate of the 'Lan case 33. The fluid discnarge Dort 33b is in cornnunica-!--ion with fluid passages formed in the ducts 23b and 23c projecting from the bottom fan cover 9. The top plate portion of the 'Lan case 33 is fixed to a lower su-rface of the bottom plate portion of the front -!-"I- partition plate 22 of the cabinet 2 through packing 22c by fastening means 22d such as screws.

The side plate 36, which constitutes a front frame of the drive motor 32, has a fluid agitating portion 36a of a concave-convex, corrugated or sawtooth sha-De on its centrifugal fan side. The fluid agitating portion 36a is a portion for agitat-Lna the low-temperature fluid between the support plate 34 for the centrifugal fan 31 and the heat transfer accelerating plate 37 efficiently by the cooperation with the whirlina flow from the fan 31.

The heat transfer accelerating plate 37 serves not only as motor mounting means for fixing a stay portion 32a of the drive motor 32 while passing through the side plate 36 by using fastening means 37b such as screws but also as heat transfer L accelerating means for transferring the heat generated from the drive motor 32 efficiently to the fan case 33. The heat transfer, accelerating plate 37 has a circular through-hole (not shown) through which the side plate 36 passes and is fixed to the bottom plate portion of the fan case 33 by fastening means 37d such as screws.

Next, the low-temperature-side centrifugal blowers 5 will be described below in detail with reference to FIGS. 70, 76 and 77. FIG. 76 is a diagram showing a structure for mount- ing each cent--.;..fugal blower 5, and FIG. 77 is a diacram showinq a structure of the blower 5 schematicallv.

The -two low- temperature-s -ide centrifugal blowers 5b are mounted above the heat exchanger 3 and are accommodated between -145- the top fan cover 8 and the upper end portion of the cabinet 2.

The centrifugal blowers 5 are each provided with a centrifugal fan 41, a drive motor 42 for rotating the centrifucal fan 41, and a fan case 43 which accommodates the fan 41 ro"Catably.

The centrifugal -fan 41 functions to circulate the low-temperature a4;_r compulsorily within the low temnerature-side heat transfer space 18. In -he same manner as the centrifucal fan 31, the fan 41 includes a pluralitv of blades and a disc-shaped support plate 44 for supporting the blades. The support plate 44 is fixed onto an output shaft 4-5 of the centrifugal fan 41.

The drive motor 42 is fixed by f-tt_ 4 _ng a heat transfer accelerating plate 47 onto the outer periphery of a side plate 46 which is positioned closest to the centrifugal fan 41. On ton of the drive motor 42 a cooling fan 48 is mounted onto the output shaft 45 for blowing the atmospheric air (hich-temperature air) to the drive motor 42 to cool the motor.

The fan case 43 receives the centrifugal fan 41 thereir, and seDarates the high- and low- temperature-s JLde heat transfer spaces 17 and 18 from each other. In the interior of the fan case 43 is formed a vertical comDulsory circulation flow oath 49. As shown in FIGS. 70, 76 and 77, the fan case 43 has a fluid suction pcrt-- 43a for suckinq the low-temperature air to comoulsory circulati-on flow path A9, a 11-lu-4d discharge por, 255 which i s in co=unication with the associated low te-,-.:)eratu_-e-side discharge Dort 21b fo_rmed in the cabinet 2, and a fan mountina ocening 43c -fcrmed _'n -he too r)late por-_icn, the onenina 43c having a diameter larcer than theoutside diameter of the centrifugal fan 41.

The fluid suction port 43a is formed in a bellmouzh portion 50 of the bottom plate of the fan case 43. As shown in FIG. 77, the bellmouth portion 50 also functions as a weir portio- -for preventing droplets suchas -rain water entering throua'l- the fluid discharge port 43b f-rcm leaking into the cab-ine-r-- 2 (-the low- temperature- side space 18) through the bottc-,r,i;D-late portion of the fan case 43. Further, as shown in FIG. 77, the fluid discharge port 43b also functi-ons as a droplets discharge port for discharging drc-,:1e-t--s staying in the r4 or bottom of the fan case 43 to the exte - As shown in FIG. 70, the bottom plate portion of tne fan case 43 is fixed to the to plate upper surface of the front part,:Ltion plate 22 of the cabinet 2 th--oL:ch packing 22a by fastening means such as screws. The front portion of the fan case 43. is fixed to the door plate 21 of the cabinet 2 by fastening means 21d such as screws.

The side plate 46, in the same manner as the side plate 36, cons-__4;_tutes a front frame of the drive motor 42 and has, on its centrifugal fan side, a fluid agitatinq portion 46a of a concavo-convex, corrugated or sawtooth sinape. The fluid agitating portion 46a is a portion -for agitating -he low-temnerazure Jffluid between the support plate 44 for te_ centrifuaal 'Lan 41 and the heat transfer accelerating plate 47 efficiently by the cooperation with the whi r7 4 ng flow from t',e fan 41.

-147- The heat transfer accelerating plate 47 functions not only as motor mounting means for fixing the a stay portion 42a of the drive motor 42 while passing through the side plate 46 but also as heat transfer accelerating means for transferring the heat generated from the drive motor 42 efficiently to the fan case 43. The heat transfer accelerating plate 47 has a circular through-hole (not shown) through which the side plate 46 passes, and is fixed to the top plate portion of the fan case 43 through packing 47c by fastening means 47d such as screws. The heat transfer accelerating plate 47 and the stay portion 42a of the drive motor 42 constitute a separating portion which forms part of the fan case 43, and also const-4 tute a water entry preventing wall for preventing the entry of water or the like from the low-temperature-side heat transfer space 18 to the high-temperature-side heat transfer space 17.

In the high-temperature-side heat transfer space 17 of the housing 13, the electric heater 6 is disposed at the downstream side of the high-temperature-side heat exchanger portion 3a of each cooling unit 3 in the high-temperature air flowing direction. The electric heater 6 is for heating the air flowing through the high- temperature-s ide heat trans-fer snace 17 so that the internal temDerature of the closed sDace is maintained at a level not lower than the lower-! i-rn it temnerature, (e.g. f OcC), because the perf ormance cf t.he electronic parts (e.g., semiconductor elements) 11 and 12 will be deter --:o--a ted if the internal temperazure o-Iff the Closed space in the housing 13 Ls lower than tne lower-li-mit temDerazure.

-148- The electric heater 6 used in this embodiment has a calorific value of, for example, 1.2 kw.

The controller 7 is for controlling the electric devices used in the cooling apparatus 14 such as the electric heater 6, drive motors 32 of the two high-temperature-side centrifugal blowers.4 and drive motors 42 of the two low temperature- side centrifugal blowers 5, in accordance with the internal temcerature of the closed space 15, detected by a temperature sensor 10 constituted by a the=o-sensitive element such as a thermistor.

When the internal temperature off the closed space 15 is not lower than the lower-limit temperature (e.g., 0 C C), the controller 7 controls such that the two hich-temmerature-side centrifugal blowers 4 and the two low-temperature-side cen trifugal blowers 5 operate in Hi (large air amount) or Lo (small air amount) mode, and turns OFF the electric motor 6.

Further, when the internal temperature of the closed space 15 is not higher than the lower-limit temperature (e.g., 0 C C), the controller 7 turns OFF the drive motors 32 of the two low temperature- side centrifugal blowers 5, controls such that the drive motors 42 of the two high-temperature-side centrifugal blowers 4 oDerate in Hi (large air amount) or Lo (small air amount) mode, and turns ON the electric heater 6.

A method of changing the drive motor 42 of each low temoerature-side centrifugal blower 5 in this embodiment will be described below briefly with refe-rence to FIG. 70.

Firstly, the fastening means 24c such as screws are -149- taken off, and the top fan cover 8 is detached from the upper end of the cabinet 2. Next, the fastening means 47d such as screws are taken off, and the fan case 43 is detached from the heat transfer accelerating plate 47. In this case, the drive motor 42 can be taken out easilv from tie fan case 43 to the upper side of the heat exchanger 3, while the heat transfer accelerating plate 47/ is mounted to the stay portion 42a of the drive motor 42 and the centrifucal fan 41 is mounted on the r 4 output shaft 45 of the d -ve motor 42, because the diameter of the fan mounting opening 43c is larger than the outer diameter of the fan 41.

Thus, the drive motor 42 can be detached easi1v from the fan case 43 without the complicated work of taking out the centrifugal fan 41 from the output shaft 45 of he drive motor 42 within the fan case. when mounting a new drive motor 42, firstly, the support. plate 44 for the centrifugal fan 41 and the output shaft 45 of the drive motor 42 are fastened together by fastening means such as bolts, and the drive motor is mounted to the fan case 43 in the seauence reverse to the above.

Next, a method of changing the drive motor 32 of each high-temperature-s-ide centrifugal blower 4 in this embodiment will- be described below briefly with reference to FIG. 711.

In the same wav as above, firstlv, the fastening means 25c such as screws are taken out, and the 10ottcm fan cover 9 is detached from the lower end of 'the ca'_-_',ne-!-- 2. Next, the fasteninc means 37d such as screws are -Laken out, and the heat -150- transfer accelerating plate 37 is detached from the fan case 33. At this time, the drive motor 32 can be taken out easily from the fan case 33 to the lower side of the heat exchanger 3, while the heat transfer accelerating plate 37 is mounted to the stay portion 32a of the drive motor 32 and the centrifugal- fan 31 is mounted on the output shaft 35 of the drive motor 32, because the diameter of the fan mounting opening 33c is larger than the outer diameter of the fan 31.

Thus, the drive motor 32 can be removed ea S4 IV .L f rom the fan case 33 without the complicated work of taking out the centrifugal fan 31 from the output shaft 35 of the drive motor 32. When mounting a new drive motor 32, firstly, the support plate 34 for the centrifugal fan 31 and the output shaft 35 of the drive motor 32 are fastened together by fastening means such as bolts, and the drive motor 32 is mounted to the fan case 33 in the sequence reverse to the above (see FIG. 76).

An operation of the cooling apparatus 14 of this embodiment will be described below briefly with reference to FIGS. 68 to 77.

By starting the supply of an electric current to the drive motors 32 of the two high-tempera".-,ure-side centrifugal blowers 4 and the drive motors 42 of the two low temperature-side centrifugal blowers 5 when the internal temDerature of the closed space 15 in the hou S4 ng 13 is not lower than the lower-limit temperature (e.g., 0 z C), the centrifugal fans 31 and 41 start operating. As a result, a circulating -flow of a high-temperature air (clean inside air -151- not containing a foreign material such as dust or moisture; inside fluid) is formed in the closed space 15 (high temperature-side heat transfer space 17) formed within the housing 13. On the other hand, a C-4-rculating flow c-f a low-temverature air (foul outside air containing a foreiqn material such as dust or moisture; outside fluid) is formed in the low- temperature- side heat trans'-fer space 18 formed outside the housing 13.

In each of the cooling units 30 which are mounted while passing through the fluid separating plate 13a of the housing 13, the refrigerant sea-led in each cooling tube 27a of -the hich-temnerature-side heat exc.liancer Dortion 3a is boiled and vaporized by receiving the heat which has been transferred "from the high-temperature air through the heat receiving fins 30a.

The vaporized refrigerant passes through the high temperature- side top tank 28a and the first connection pipe 3c and is condensed on the inner wall surfraces of the condensinQ portion Y of the low- temperature-side heat exchanger portion 3b which is exposed to the low-temperature air and is held low in temperature. The resulting latent heat is transferred to the low-temperature air through the heat radiating fins 30b.

4 The refrigerant thus condensed -In the ccndens-Lng portion Y, as shown in FIG. 75, drons along the inner wall surfaces of the cooling tubes 27b due -o J_ts own weight, passes tn--ouch the low-temperazure-side bottorr. -::ank 29b and the second connection Dime 3d, and reaches the boilinq portion X of the high-temperature-side heat exchanger portion 3a. in this way, -152- the --e---':----:gerant sealed in the cooling tubes 27a and 27b repeats boilinc and condensation alternately to transfer the heat of the 'nicn-temnerature air to the low-temperature air so that the heat f-rom the electronic parts 11 and 12 can be releas=_-_ -4n the plural stages of cooling units 30.

--he electronic parts 11 and 1-2 can be cooled a ni_'xzure of the hightemperature air (clean air prese=-- --- -"-,e nous-ing 13) which circulazes within the high heat transfer space 117 of the closed space 15 and --c-,;-temperature air (foul air n-resent outsidethe hous'-- whic'n circulates within tne low-temperature-side heat suace 18.

tne internal temperature o-ff closed siDace 15 In the hcusina 13 is lower than the lower-1-41 m _4 -_ temperature (e.g./ 0::C), an ele-c-tric current is supplied to the electric he-ater 6 to heat the air flowing through the high-temperature-side heat transfer snace 17. At this time, the two low-temperature-side blowers 5 are kept OFF.

on the other hand, by rotation of the two high tempe=-_ure-s';_de centrifugal blowers 4, the high-temperature air within the clo-sed sTDace 15 in the housing 13 flowina frcm the electronic parts acco7..7.oda-!_-ing space 16 which accc=o_--;a-:es the electronic parts 11 and 12 therein, through the h_ia---_e-rerQ=-L-ure-side suction port 23a formed in the rear 2 S oartitlcn claze 23 of the cabine-r-- 2 and, enters the cool-1-na apparat-_s 1-', as shown in FIGS. 62 and 69. T II e higi-temneratl_,re which has thus entered the cool 4;_n-- a-z-,arat'_'s -153- 14 passes the narrow path surrounded by both fluid separating plate 13a and rear partition plate 23, and thereafter passes through the hightemperature-side heat exchanger portion 3a. That is, the high-temperature air passes between adjacent cooling tubes 27a whiLe the heat is absorbed by the heat 1 4 receiving L-Lns 30a.

In eac.-i of the two hJgh-zemperature-side centri f 17 gal blowers 4, as shown 4n 77G. 71, the cooling fan 38 also rotates together with the cer.tri-fugal fan 31. A s a r e s u I t, t e hiah-temnerature air is sucked to the inside of tne bo-:--c.TL cover 9 through the suction ports of the]:oztom cover to cco7 the drive motor 32 and is discharged through the disctarce Dorts 25b into the electro-ic parts accommodating space 16 in the closed space 15.

Fu_rther, bv the cooperation of!Doth fluid agi-tatIng por-:ion 36a formed on the cenzrifucal fan side of the sJLce plate 36 and rotating current from the centrifugal far 31, the low- temperature fluid between the support plate 34 and the he-:,.- g4 transfer accelerating plate 37 is a -tated efficiently to cool t:ie drive motor 32. Bv transferring the heat cenerated frorn.

t'-e drive motor 32 to, the 'Lan case 33 through the heat transfer t4 rg 4S C007 te 37 ef-ficient-y, the dr-ve motor 32 ed acce era pla_ g.z 4 eff-cientlv. on the other hand, hy rc-:at-- ic-r of the centri.-Lugal -cans 4]. cff tne two low-temperature-side Cent-rifuaal blowers 5, the 7 1cw-temperature air c __rcula-,_ ing with _J- -z:.,ie lo-,,;-tempera tures he-;z-_ trans-fer sr)ace 18 for,-ne,4 cu-_side the ncusing 13 F70WS the exter-'cr Lnto the cooling apparatus 14 through the low temDera-:ure-side suction port 21a formed in both door plate 21 and 'Lrc--: plate 22 of the ca'_-_net 2, as shown in FIGS. 6E anc 69. The low-temperature air which has thus enterec t'-e cooling apparatus 14 passes through the low heat exchanger portion 3b. That is, the low- air passes between adjace--_ cooling tubes 27b j and t-.e 3-_f -_'ne vaporized refrigerant which has been boiled r the -=tion X is absorbed bv --e heat radiatna fins 3 Ob.

-n eac- of the two low-temiDera--ure-side centrifuaal blowers as shown in FIG. 70, the ccoli"q fan 48 also -rotates toget'er w_'-:i the centrifugal fan 41. --ks a result, the high- --emperature air is sucked to the ins4Lde of the top fan ic cover 8 zhrcucn the suction ports 24a of the top fan cover to cool t'-_- drive motor 42 and is discharged into the electronic parts aCcomr.cdating space 16 in the closed spaced 15 throuan the di_-cnar_-e Dort 24b.

I - Fur--her, bv the cooperation o-j" both fluid agitating nortion 16 form.ed on the centrifugal fan side of the side plate - - -zi na fan 41, the 6 a n: current from the cent-T-_ low-te=e_-_=-_u_-e --Fluid between the sucr)cr-- 44 and the hea-_ trans.;_:-_- accelerating plate 47 is agitated effficiently to ccc-7 the dr-17e mc-or 42. By transferr7nu the hea- generated from l L t-ne dr_ve mczDr 42 to the fan case 43 throu# the heat zransfer 71a-e 47 efficientIv, the drive motor 42 ils cooled -155DIp EE SaSP3 Up; a-__;C Gl: U- Z PUP Z SaCaO12 Gi:;o gt pup g7 s-.;Pqs -nd-ric G,::, uic:z; I;- cup T;- sup; C7 17-::nL1@3 aT4; f)U7.1,C)U:a:, Sl-- UZMS Y_-OM up -ncT-: -.m paq3p,Gp.7o paqunotu Gq Zt pup ZE s.::c,:cir aAT_7p gun ' Tu; nE) pui:? EE sGsp-- ui?; au- o; Tqpq:,PGp Pax-,; a:rP Z PUP;__ S:10-.Oul aA- L:IP GT4-- Pup EtH Sas7=?Z) 'Llp; -+ -. Da d s aa IDasc'3s-rP L PUP LIE sG-)-e-Ld f)u-L-p.:ZG- G-,: uaa,,i;aq T@ATL a::) Z) P 07 :zazs-L:P:zq -4p@Tq @q-4 pup,Ta=DGdsaa lCt PUP EE SaSPZ) UP7 @U- UT Palz:!O; @-TP T Pup TE SUP; 7P5nZ7l;-L:@3 GT4- -0:ZG-_aUIP-CTD @7)TSnTLAC Gun Upq4:1@5:1PT IGaGIZPTP P BUTAPq DEt PUP DEE sBu-Luado SuT;unoir 14uGu:7poquia STT4: Oq BUTPICZDV qqq 13@Aoa3oul 07 -Zt PUP ZE s3c--cuI aATrP G144;-10 90us= -::Ga 9 T SuTUT?IUTPIU @ql @AO:z(3ulT 0-- aTq-ssod sT qT j"7;u@nhesuc3 L ::G5UPLDxa npaq a T-T n 14Tm G 7;Z-:1 G -4 -LI T UP Bu- SnP3 a-qq 'XC:17 DaqDp'-Gp PUP 04 pGaUnoul anc-q-_Tm tT TOC3 Ga UP3 Zt --040lu aAT:Z'c aTq; -.Pu; os ':)S-_-Pu3xa --eGq aqq apoqe P=_xT7 Tqpqop-.ap sT Et. aoqoui aA-ip Gqq pup E z@BupT4DxG qpaq 0 T GPTS-@ n P:Z a aT4_ aAoqP pasods-p s- c:9mOTq L adul -!"OT aqq;0 GTOT4M Gun a -LI U PJU Ga:p S G- U T E.7qsUpqZ)x@ V, tT sn:P_P3dp -PGT4 Gqq 'q-4Tm GDUG:r@_-7G;T-T Ll ? ED U BUTTOOD @T-T-4 WO PUP 0- panu,-,,Olu aq ulez) ZE -70-cul GAT-In @Iqq:PT4n_ CS 'E aaEupu3xa qp@q aq- mc-Laq pGx-L: A-Tqr:?qz)pqap S- E:IO-4oui aAT:lp -3-q pup E 3GfDUPT43x@ 3T4 Gqq mOTac pasods-rp ST t S-TamOTq TPBn_:TTL:z.UGZ) G14:;0 GT014M @TT-4 ' @Aoq-E? paq-raosap sp 'qu;q=poquia s7i: o-4 fDu-L paoDov paqTiosap aq T 7rM:uaunpoqma =4:;o uv and 42 can be further improved.

T r " j C.1-S embodiment, since the heat transfer acce-,:)Iates 37 and 47 are formed o.-f' a metallic material conta_r_4--_ al,.:minum as a main component which is sunerior in heat the heat generated from the drive motors 32 and 12 fel eased ef ficiently to t1rie fan cases 33 and 43 bv 7-,e_=-_- cf suc- a sunerior heat conduc,__vitv. Consequently, the '-em_=-_ re-z-'stance of the drive mc-Lc--s 32 and 42 can be or Zne S4 imp r e - _Lze of both motors can -'-e reduced due to -_'-e heat accelerating effect.

-1cccr'ina to this embodiment, as shown in FIGS. 70 and 77, te '-=7 IT-CUtl, portion 43a for receLv_4na droplets contained 1. L in t-e 1--w--e-perature fluid (ouz:side air) to preven-_ the drople-:S -from leaking to the heat exchan-ge 3 side through the bottom, o-f --'re fan case 43 is formed in the fan case bottom, and the discharge port for discharging the drople--s stav:'-na Ln 'the bottom of the fan case 43 to the exterior of the cooll'nc ar):Daratus 14 is formed integrally with the fluid discharge por-. 43. Consequently, even w-Jr-hcut the use of any special parts or equipment, droplets such as rain water conta-4ne--4 --'zhe low-temperature fluid and entering the 'Lan case 13 can be certainly received and drained, with simple struc-_,:re. Accordingly, since such drco,e-!-s can be p-revented from en-iefi-a the cooling apparatus 14, that Ls, the he-=-:

exchanaer 3, the corrosion of the heat exchancer 3 can be Dreve-ze-d even when the heat exchanaer 3 is formed o--" a mater-'al w,-_c'- mav be corroded with the droDle-_s, such as a -157- metallic material of as aluminum or the like.

The cooling apparatus 14 of this embodiment is provided with the heat exchanger 3 including the cooling units 30 disposed in plural stages in the air flowing directions in each of which the hiah-tempe-rature-side heat exchancer portion 3a as the boiling portion X and the low-t-emperature-side heat excnanger portion 3b as the condensing pc---.4;__-n Y are connected annularly by the two first and second connection pipes 3c and 3d. With this construction, since a circalating flow of the refrigerant is -Formed in each cooling unit 30 and the collision between the vaporized refrigerant lboiled -,.Ta::)o--r) and the 14aU-:J refrigerant (condensed liquid) can be prevented, the he'at radiating performance (cooling per-forr-nance, of each coo-' ing unit 30 can he improved. By dispos-ing the cooling unit 30 in ulural stages, it becomes possible to further improve the heat radiating performance (cooling perfcrmance) of each coc-7-'ng unit 30 in the heat exchanger 3.

A twenty-first embodLazient of the present invent-Lcr. w1:11 be described.

FIGS. 78 and 79 are diagrams showing a side plate of a drive motor and a heat transfer accelerating plate.

As shown in FIG. 79, on the cen-rJfugal fan side of a heat transfer accelerating plate 47 used in this embodiment there is _-'rormed4 a heat radiation accelerating porticn 47a havina a Plurality of Ccncen-_-ric grooves which are forme-_ in a a 4 in C the same direction as a fluid ____ - portion 46a of a side r-ent 4 ';_ z,_-te 46, i.e., in the C 4 rcum-ce on. W it h t.-I 4 s construc-.-Jon, the heat radiating effect from a drive motor 42 to the azziosoteric fluid (high-temperature air) through the heat zr_=nsfer accelerating plate 47 is promoted, so that the heat res--stance of the drive motor 42 can be imnroved or the motor car be further downsized as compared with the twentieth embod-'ment.

z-..;enty-second embodiment of the present invention Will -- -- - - bed with reference to FIGS. 80 and 81.

tructure of a low- is a diagram showing a s_ 0 temper _=-,:re- s 'Lde centrifugal blower scnematJLcally, and FIG. 81 is a showing a support plate for a centrifugal fan.

on the motor side of a support plate 44 for a centr__-12-_,=_;z_' fran 41 in this embodiment there is formed a fluid agita-:-:ng portion 44a which includes ridges or grooves extendina radially, centered on an output shaft 45. By the cooperat'on of the fluid agitating portion 44a of the support plate 4 4, a -fluid agitating portion 46a of a side plate 46 and a current from the centrifugal fan 41, the low-te-icerature fluid between the support plate 44 and a heat transfer accelerating plate 47 is agitated ef -ficiently, so that a dr--:ve.7,otcr 42 can be cooled efficiently. Further, since the support plate 44 is formed in a concave-convex shaDe, the fluid agitatinc --crr-ion 44a functions as a reinforcing rib, so that the s--reng--h of the centrifugal fan 31 can be also improved.

A -:wenzv-third embodiment of the oresent inveritLon wil 1 be descr-'bea; wit1t reference to FIG. 82.

FIG. 82;s a diagram showing a structure cf a low -159- temperature-side centrifugal blower schematically.

In this embodiment, a bottom plate portion 51 of a fan case 43 located near a fluid discharce nor-, 43b is declined bv W 4 a Qredetermined angle, e.g., 2- -3) toward the exterior _--h 4 resr)ect to the hor-;'_zontal d-Irection. According to this construction, droplets such as rain water can be certainly drained and prevented from leaking to the heat exchanger 3 side throuqh the bottom of the fan case 43 even when the amoant cl arge, as com:ared w'th the twentiet- droplets is embodiment in which -he bellmouth oorticn 50 for weir of the droplets is formed in a small plate portion of the fan case 41-3 is DOS4--' and the bottom of the fan case _;_L__oned horizontal.

A twenty- -four th embodiment of the p-resent invention will be described with reference to FIGS. 83 and 84.

FIG. 83 is a diagram showing a schematic structure of a low-temnerature-side cent-rifugal blower, and FIG. 84 is a diagram showing a main structure of the low- temperature-S ide cen--rifugal blower.

-4 A low-temperatu--e-side cent -fugal blower 5 according to tt4 _s embodiment, as in the twentieth embodiment, is provided a centrifucal 'an 41 'or circuat"ng a low-temperature air w - - L - - =anu-sorilv within the low-temnerature-side heat trans-F;= space 18 (a compulscry circulat-Lon flow pa--n 49), a drive mo--cr 4/2 for rotating the cen-Lri_-'uaal f an -:_1, and a fan case 4_3 w -=,=-'ves therein the centr-fugal fan 41 rotatably.

The cen--rifuaal 'Lan 41 includes a plurality of blades -_ Cl an-_ a disc-shaped sunocrt jlate 41. support plate 42 is -160- fixed to ar output shaft 45 of the fan 41. The drive motor 42 is fixe-_ bv fitting a heat transfer accelerating plate 47 on the outer Der_'=hery of a side plate 46. heat -ransler acceleratinq plate 4- has a circular J_7e te passes.in a through which the side pIaL state -L-e side plate 46 passes thrcuc'n the throuch-ho7e 17e, a portion 42a of the drive motor.12 is fixed to the heat 7-r-=-5-fer accelerating plate 47 by 'ffastening means 471b such a s s c f e='. -,, S - A sealant 47f, e.g., sili----ne sealant, is attached to t- e ou -:;-zr periphery of the stay por-r_-ion 42a and the fasten_= nor-- -4on of the plate 47 to im::)--ove the airtightness between --'-e lo-.,;-temDerature-side heat transfer space 18 (CoMr, -C- circulation flow path 4 and h e hich- 7 tempera-r_-u_-e-s.J_de heat transfer space 17. The heat transfer acceleratna plate 47 and the stay portion 42a of the drive motor 42 ccnstitute a separating port-'on and a water entry orevent'na wall both forming part of t'n.e -fan case 43.

The f:an case 43 has a fan mountnc oneninc 43c of a d4 ame--er larcer than the outer diameter of -he centrifugal fan 41. The cerizheral edge of the fan mount4na openJng 43c is I - - a annular rib portion 43d for performing a linear for,me seal wit' a rubber packing 47c. A tacned hole 43e for mears 47d such as screws is forme,_4 in the fan case 43, t-=- f_=Steninq means 47d being fc_- fas-:enJL_ng and fixing ieat tra-s-':er accelerating plate 47 to the ton plate portion of -he an case 43'. Tn -he vicinitv o_ tne tacced hcle is L crme-_ a n" a-e stopper 43f for constant-y maintaining a -161- clearance between the rib Dortion 43d and the packing 47c to prevent a breakage of the packing. The top plate portion of the fan case 43 near the tapped hole 43e is formed as a ring-like convex portion 43g in which the burring process is performed toward the bottom plate portion.

In this embodiment-, since the per-4Dheral edge of the fan mounting opening 43c formed in the fan case 43 and the outer peripheral portion of the heat transfer accelerat-'ng plate 47 are sealed with the packing 47c which is in the shape of an annular plate, and the perinheral edce of the th.-rough hole 47e formed in the heat transfer accelerating plate 47 and the outer peripheral portion of the side plate 46 of the drive motor 42 are sealed with the sealant 47f, a foreign mar-erial SUCIrl as dust or moisture which has entered the low temiDerature-side heat transfer space 18 (compulsory circulation flow path 49) through a fluid suction port 43a of the fan case 43 does not enter the high-temperature-s'l-de heat transfer space 17 through the fan mounting openinc 43c formed in the top plate port-ion of the fan case 43.

Accordingly, the heat transfer accelerating plate 47 and tne stay portion 42a are disposed so as to close the fan mcuntng opening 43c of the fan case 43 which hermeticallv se-arates between the nigh and lcw-temperature-side heat trans fer spaces 17 and 18 together wit the fluid separating plate 2 5 13a. Consequentlv, there is no poss-ibilitv that a foreian, -ma--er4al enters the 1-iigh-temperat'are-sLde heat transfer space 17 trougt the fan mounti'n_- open-na 13c 'from the ccmr)u_1so_-y -162- circulation flow path 49 into which the outside air flows.

in this way, it is possible to prevent the occurrence of inconveniences such as breakdown of the internal parts or defective insulation caused by the entry of a foreign material into tne drive motor 42. Besides, since it is possible to prevent a foreign material such as dust or moisture from entering the high-temperature-side heat transfer space 17 througi,, the low- temperature-s ide heat transfer space 18, the foreign material is not deposited on the electronic parts 11 and 12 mounted within the closed space 15 and hence there is no possihility of the malfunction of the electronic parts 11 and 12.

Further, since the entry of a fore4an mater4al such as dust or mixture can be prevented without accommodating the whole of the drive motor 42 within the fan case 43, the work for mountina and changing each lowtemperature-side centrifugal blowers 5 can be simplified and thus it is possible to improve the maintaining performance of the drive motor 42.

Modifications of the seventeenth to nineteenth embodiment will be described.

The cooling apparatus- 14 provided with the heat exchanger device 21 according to these embodiments is utilized in the case where the heating elemenzs such as the electronic Darts 1: and 12 need be accommodated in -the closed sDace. The case where the heating elements need be accommodated in the closed sDace includes -the case where heating elements are used under the severe environmental condition containina, for -163example, oil, water, iron powder, corrosive gases, etc., the case where inactive gases (helium gas, araon gas, etc -) are used to prevent arcing or oxidation of contacts at the time of electric intermittence, or the case where gases harmful to the human body (for example, such as hvdrocen flucride decomnose/4 17 from L-uorocarbon) are prevented --from leaking outside.

in these embodiments, a mult--L.-E_7cw pass type heat exchanger having corrucating fin tubs is used as the C001-41na unit 3, the laich temperature-side heat ex-chancer 3a and the low te.mceratu--e-side heat exchanger 3h; however, a heat exchanger having plate fin tubes, a heat exchanger having fine pin-flin tubes, a heat exchanger of a serpentine type having flat tubes ben-:: in a zigzaa manner, and a heat exc-lanqer of a drawn-cup type having a plurality of laminated cooling tubes in which two pressed plates are connected to each othe-r, may be used as t-e cooling unit 3, the hich tempe--ature-side heat exchanger 3a and the low temperature- side heat exchanger 3b. Slit f ins c- louver fins mav be used as the heat receivina fin 6a or tne radiating fin 6b.

In these embodiments, hich-temperature gas such as hch-temneratu_re air, heated by heating elements such as the nl-_,--ronic Darts 11 and 12 is used as a--:r in the housing 133 and hi=h --emcerature f-,uid as fluid in -he casing (inside air); nc-,;ever, cooling water for cooling -:he I neating elements such as the electronic Darts 11 and 12 and hi-n-terrzerature liquid such as (including workinc oil- an,_4 lu,bricatinc: oil) may be usec' as a hig',-,-tempera-ture in the Same manner, not only -ow temperature gas such as low temperature air but also lowtemperature liquid such as water and oil may be used as air OUtS4de L the housing and low temperature fluid (outside air) which is fluid outside the casing. In these cases, pumps are used as the inside fluid circulatingmeans and the outside fluid ---4--culating means. As means for actuating the pump, and the centr--"-":'uaal fans 31 and 34, not only the electric motors 32 and 33 as in these embodiments but also the internal combustion engine, water mill, or windmill may be used.

A twenty-fifth embodiment of the present invention will be described with reference to FIG. 8r'.

FIG. 85 shows a cooling apparatus incorporated in an electronic apparatus according to this embodiment.

For example, the electronic apparatus is installed in a radio base station of a mobile radio telephone such as cordless teleDhone or car telephone. The electronic apparatus includes a housing 80 which hermetically houses therein electronic parts (heat generating elements, 7 such as a trans receiver and a power amplifier in a hermetically sealed state, and a cooling apparatus 1 which is mounted within the housing to cool the electronic parts 7.

The electronic parts 7 are heat generating elements which performs a predetermined operation when an electric cu--rent _JS supplied thereto and generate heat (for example, a semiconductor switching element constit-ut]-na a high-frequency switching circuit incorporated in a trans -rece iver, and a semiconciuctor amplifier element such as a power trans.4stor -165- incorporated in a power amplifier).

The housing 80 seals an interior thereof hermetically from the exterior and has a closed space 9 in the interior.

The closed snace 9 is hermeticaliv separated completely from the extez--ior by means of: a fluid separating plate (medium separaz-inq plate) of the cooling apparatus 1 in order to prevent the performance of the electronic parts from being deter_'cra-zied due to tn.e depo S4 tion of a foreian material such as dust or moisture on the electronic parts 7.

Sv the -ffluid separating plate of the cooling apparatus 1 and a casina of the system 1, the closed space 9 is parti tron4C tioned Lnzo an elec _L parts accommodating space '-for accommodating the electronic parts 7 and a 1, --c:h temperature-side heat transfer space 11 w1i ich serves as an inside passage. in the hich-temDerature-side heat transfer space 11, the flow path area on the upwind side is narrow to minimize the deDth of the cooling apparatus 1, and the flow Dath area on the downwind side is wider. Tn the housina 80, moreover, there is formed a lcw-temoerature-side heat transfer snace 12 as an outside nassaae which is separated hermetJI-Cally zne high-temperature-side heat trans-fer space 11 by means of the fluid separatina plate.

TI-ie cooling apparatus 1 I's furtier provided with a casing 91 4ntegra 7 w-t- the hcus'na 80, -wo upper centrifuga 2 5 blowers 1E for genera,_-_nq a flow olf a iow-temperature air _ 7 (outs-'de flu-J,-4, low-temperature _uid), two lower centr.Lfu-cal blowers 15 _or genera-_4nq a flow of a hic:h-temperature a-,:Ir -166- (inside fluid, high-temperature fluid), an electric heater 19 for maintaining the air temperature in the closed space 9 at a level not lower than a lower-limit temperature (e.g., 0 = C), and a controller 82 for controlling the supply of electric power to the electric devices of the cooling apparatus 1.

The cas.Lng 81 includes an outer wall plate 83 located on the outermost side of the housing 80 and a rear partition plate 22 which surrounds the high-temperature-side heat trans-fer sDace 11. The outer wall plate 83 and the rear partition plate 22 are fixed to the housing 80 by bonding such as sDot weldina or by fastening means such as screws or bolts.

The two uDDer centrifugal blowers 18 each have a c e n t r -4fugal far, for generating an air flow in the low temperature- s id e heat transfer space 12, an electric motor 'or rotatina the centrifugal fan, and a scroll casing which houses therein the centrifugal fan rotatably.

The two lower centrifugal blowers 15 each have a centri-Eucal 'Lan for generating an air flow in the hic- temperature- side heat transfer space 11, an electric mo-or ffor rotating the centrifugal fan, and a scroll casing which hou-ses therein the centrifugal fan rotatably.

The electric heater 19 is for heating the air flowing through the high-temperature-side heat transfer space 1-1 so that z:n.e internal temperature of: the closed space 9 _J s maintained a -_ a level not lower t 1 a n the lower-11 _4 m I -_ tem=era-L_u_-e (e -:7., 0::C), because the performance o-f -the electronic parts (e.g., semiconductor element) may deterio-rate -167- when the J_nternal temperature of the closed space 10 is lower than t',,-- lower-lim-it temDerature. The electric heater 19 in this em_'-cd_'ment has a calorific value of 1.2 kW, for example.

7'-e ccntroller 82 controls electric motors of the two upper blowers, electric devices such as eleczric motor=- zf -."-ie -two lower centrifugal blowers 15 and the electric heater Ln accordance with the internal -emr)erature cf the clos;=,4 zz-ace 9, det-e-c--ed by a temperat-ure sensor 84 constituted by a -_1-__-7.c-sensJ1_tive element, e.a., thermlstor.

" - 'l-- e n z - ne internal t-emc)erature o-f --he closed; sr)ace 9 is not lc-.-er -'nan the lower-limit temperat,,.:re (e.g., 0 C C), the -4 fU 1 cont: er 22 controls such that the two uocer cent-- aa blowers and the -:= lower cen-_ r 4 L-fucal tiowers 15 coerate in Hi (larce air amount) or Lo (small air amount) mode, and turns OFF the e--ec--ric motor 19. When the internal temperatdre of the clcsea s-oace 9 is lower than the lower-limit temiDerature (e.g., O-C'/, the control ler 92 turns OFF the electric motors of tne two ucz)er centrifugal blowers 18, ccntrols such that the elec-zric -notors of the two lower centri'Luaal blowers 15 operate _n H-4 (large air amount) or Lo (small air amount) mode, and The cool-4na appara-:i,_,s 1 will be described. 86 is a front vle-,N; of the cool' L - inq apparatus 1, F:G. _45 side vie%.: -_'nerec-ff, and F7 C-:

88 -s a bottom o-7 the cco'na la-narazus 1 aS seen -.ff_-caLi below. In the coc!-- an,,ara-lus of emtcdi7re7.-::, heaz: LS absorbed f-rcr-a a medium, e.g., high-temperature air) in the high temperature-side heat transfer space 11 and the thus-absorbed heat is released to a low-temperature fluid (corresponding to a low-temnerature medium, e.g., low-temperature air) in the low-temperature-side heat transfer space 12 and separated from the hich-temDerature fluid by a fluid sepa-rating plate 2.

As shown in FIG. 86, the cooling apparatus 1 includes a refrigerant tank 3a constituted by a plurality of heat absorbing tubes 31a disposed on the high-t emperature fluid side with respect to the fluid separating plate 2, a fluorocarbon-type refrigerant 8 (not shown) which is sealed into each heat absorbing tube 31a and is boiled and vaporized by receiv-Lng the heat of the high-temperature fluid, a low tempera ture-side communication pive 34a and a high-temperature side communication pipe 34b, one ends of which are hermetically communicated with the refrigerant tank 3 and the other ends of which extending to the low-temperature fluid side through the fluid separating plate 2, a condensing portion 3b which is herme-L-icallv communicated with the other ends of the low and high-temperature-side communication pipes 34a and 34b, the condensing portion 3b including a plurality of radiating tubes 31b and being located on the low-temperature fluid side wit'n reszect to the fluid separating plate 2, heat receJ_ving -F 4 ns 6a attached in a fused state (for example in a brazed st-at-e-) between adacent heat absorbing tubes 3-1a in the refrJaerant tank 3, and radia-L-Lng fins 6b attached in a fused szate (for 71 examT:);_e _ a brazed state) to between adjacenz --adiating tubes -169- 31b.1-n the condensing portion 3b.

in this embodiment, as shown in FIG. 87, a plurality of the cocling un_ts are laminated (there are three units]Ln this embod-":-,e-t; however, two or four or more apparatuses may be emDlove-_', in the cooling arcaratus 1.

le fluid seDarat'Lnc plate 2 constitutes one wal I surface --f --ne closed szace, an _nterior of which becomes at h4Lch and --'s l'ormed of a me-t-allic material such as alum 41---,:-: fcr ex-ample and is integrally Joined (for example, j braze- tc I-ot,) low and 'aigh-temperature-side con-nunicat-'on pipes 3,21a and 341. In the ffluia- separating plate 2 are formed a plura41_-'-_-v of holes into whch the z)z)es 34a and 34t are 7n mbod_4ment, as shown 'n FIG. -he low n s e r this e.

temperazu-re-side communication pines 34a are shifted 4 al-ternazelv. Though not shown, the h-gh-temperature-s-4de commun_ca-:Lcn Q_T,-es 341D are also disr)osed in the same manner.

7 in FIG. 86, the refrigerant tank 3a includes a plurali, tv of ")eat absorbing tubes 31a disnosed; subs tant';_ally -n parallel w-J--h eac'n other, a heat absorption-side lower 2C commuricazina. ocrtion 41 located below the heat absorbing t-L:bes -'a to comm,.:--icate lower ends of the tubes 31a with each other, and a he-:---- albsorpt.-4on-side upper communic-ating portion 42 7 -ocated a-'-c,,;,e the heat ahso-riDing --uh-es 31 a to co.-mun-icate upper ends of the tu-'-es 3!a. The heat a-'-sorb-Lng tubes 31a are each Z --'n the shape of a flat tul-e having an elongated recta:-ia,.:-ar icr oblona) cross section, and is formed cff a -net-allic (e.a. a!,,:,m_4nu-n cr coccer) which is suFer-'Lcr in heat conductivitv.

The condensing portion 3b includes a plurality of radiating tubes 31b disposed substantially in parallel with each other, a radiation-side lower communicating portion 43 located below the radiating tubes 31b to commuricate lower ends of the tubes 31b with each other, and a radiation-side uccer communicating portion 44 located above the -radiating tubes 31b to communicate upper ends of the tubes 31b. The radiating tubes 31b are also each formed in Shaze oil a flat tube having an elongated rectangular (or oblong) cross section, and is formed of a metallic material (e.q., aluminum or copper) which is superior in heat conductivity.

one end of the low-temperature-sicde cOmmunication pipe 34a communicates with the heat absorption-side lower communicating portion 41 of the refrigerant tank 3a and the other end communicates with the radiation-side lower communicat-ing portion 43 of the condensing portion 3b so that the refrigerant 8 flows back to the refrigerant tank 3a after being condensed in the condensing portion 3b. The connection between the lowtemperature-side communication pipe 34a and -he heat absorption-side lower communicat-ing portion 41 is structured of a union 71 and a nut 70. More specifically, as shown in FIG. 89, the connection has a union 71 constitute,-4 bv a tubular me.T.ber which is integrally joined so as to communicate with the heat absorpticn-siie lower communic-a--ing 14a portion 41, and the low-temnerature-side cor.=ziunication oice. is fitted in 'he union 71. An 0-ring 72 for improving the -171- airtiahtness is inserted between the union 71 and the 4 t 4 COMMun-ca on z)i:)e 34a, and both union 71 and pipe 34a are hermetlically b_rouatt into communication with each other bv a nut 710 as _'Faszenina me-=ns.The connectlion between the 71ow- -7 t 4 temzerat-re-side ccmmun_Jca on pJpe 34a ani the radiaticn-side lowe-- co=l_=_ic_zt_nc portion 43 is also structured of a unior 71', and -7- 7C. 7-'-e explana-Lion thereof is omitted, because this connec-__-on is --'-e same as the connection between the pipe 34a and '-Ie-=-- abso-rpticn-s-a-de lower communicating portion 41.

ic --'-e lcw--_-emperature-side communf-ca'zion pipe 34a has a refr_::erant_ DiDe 60 and a refriQerant inlet 61 (see FIG. 8-17), with 8 being sealed into the interior from the exter_cr thrcuat the re-f_iaerant inlet 67. As shown in ie--ail in 90, the refrigerant inlet 61 includes a union 73 F L p 4 cons-_ _-v a tubular member with the re-ffrigeranz _Lpe 60 fl-ittea; t'lerein, a valve 74 disposed within the union 7 3,, a packinc 75 between the valve 74 and the refrigerant pipe 60, for imcrovLnQ airtightness therebetween, an O-ring 76 between the valve 74 and the side ozzosite to the refricerant DiDe, for imcrovinc airtightness therebetween, a caz 77 fitted on the valve 74, for '.-er-..ie-_ica_-1_Iv sealing, and an O-rina 78 disposed or 4 1-1 - the caD.

- Lproving airt-'(zhtness o- Cne er--' of: the communication -_L-e 34'b cates W -i t z h e heat a_-scr-otion-side p p e r DortLor "'2 of the reiaeran-z tank 3a an,--' the other en C co=u n ic ate s w i h the radiation-side upper comm-an _4caz: _-'na Porl--on 'a c-'= -he -ondens'nc porton H_, so t-ha':

-172- the refrigerant 8 after being boiled and vaporized inthe refrigerant tank 3 is transferred to the condensing portion 3b.

The connection between the high-temperature-s4Lde communication pipe 34b and the heat absorption-side upper communicating portion 42, and the connection between the communication pipe 34b and the radiation-side upper commun-icat-4ng portion 44, are also structured of a union 71 and a nut 70. The explanation thereof is here omitted because these connections are the same as the connection between the low-temDeratu_re-side t 4 communica -"on pipe 34a and the heat absorption-side lower communicating portion 41.

The refrigerant 8 is sealed into the refrigerant tank 3a up to the liquid level which is slightly lower than the heat port 4 absorption-side upper communicating -Lon 42 of the refrigerant tank 3a. The refrigerant 8 is sealed after the heat absorbing fins 6a and the radiat4ng fins 6b have been brazed to the heat absorbing tubes 31a and the radiating tubes 31b, respectively.

The heat receiving fins 6a are disposed between adjacent heat absorbing tubes 31a, while the radiating flns 6b are dismosed between adjacent radiating tubes 31b. Both f"ins 6a and 6b are corrugated fins formed by p-ressing and bending a!ternatelv a thin plate (having a plate thickness of acorox-imately 0.02 - 0.5 mm) of a hign-ly heat -conduct ive metal (e.q., aluminum) into a wavy shape. The 'Lins 6a and 6b are brazed (that is, joined in a fused state) to the flat outer waf-I surfaces of the heat absorbing tuhes 31a and the radiating -173- tubes 31-h-, resnect-ivelv. The heat receivincT fins 6a facilitate the hea-_ transfer from the high- t empera ture fluid side to the refr.-'; _cie_-a-nt 8. At the same time, the fins 6a also imiDrove the cf: the heat abscrb'--ing tubes 31a. The radiating fins 7 -' -::;z 7 e 6b fa----- __ the heat transfer of the refrigerant to the low--- em:: er at,-- re fluid silde. At the same -..Lme, the f ins 6b - 7 e -Lmprc. --e strengti cf the radiating tuhes 31b.

1 =oce-_7,ure for mounting the ccolirc apparatus 1 to the flu4rcr=-vrati.nq 07 a-e 2 w471 be descr4iDe-; 4 First!-;, the re_Lgerant tan.< 3a and the condensing Dort-'cr - h, are f ormed; separately. Then, the hich- temzer_n-L-_-re-s_-J'de ccnneczion pipe 34b"is connected to the union w,._4c- _:s ccmmunicat-ed with the he-=-: absorntion-side uo-'er communicat-ing oortion 42 of the refricerant tank 3a, while the low-tem-Der_=ture-side cor-L-nunication pipe 34a is connected to the union 71 w.qich Ls communicated with the heat absorption-sLde lower co=unicatina portion 41. Next, both communication pipes 34b anz-' 34a are inserted into hcIes formed in the -fluid separ-at-Ing plate 2 and are then joined to the hole portions by b--az-'na _cr examD-!--. Subsealaently, the hian-temperature-s-'de nine 3411D is connected to the union 71 which j_s ccr=,un c---- -_ed with the radiation-side cc=unicating pcrt-zon 4-4 of the ccn-_e_-s_ng port'Lcn 33b, while the 4 s CC.-7L'n":n_-c_:4tion z)-,Pe 3-a is connec-t:ec; tc -.he union 71 wtic', - 2 5 with the rad-'ation-side lower communicating zcrt t-e co=unica-t--icn pipes 34b and 34a may bea connec-:e,_J f_'rs-:i to t-e condens_= Dortion 3b side an' _174- thereafter may be inserted into the holes of the fluid separating plate 2 and connected to the refrigerant tank 3a.

However, in the case where the refrigerant inlet is attached to the communication pipe 34a, it is di-fficult for the inlet to pass through the holes, so the former mounting procedure is simD!er. The following procedure may be also adopted.

Firstly, the condensing portion 3b and the high temperature-side communication pipe 341-j are connected together, and at the same time the refrigerant tank 3a and the low temDerature-side communication pipe 34a are connected together.

After each of these is inserted inzo the holes formed in the fluid separating plate 2, the condensing portion 3b and the low-temmerature-s-ide communication pipe 34a are connected together, and the refrigerant tank 3a and the high temDerature-s-ide communication pipe 34b are connected toget-her.

An operation of this embodiment- will be described below By starting the supply of an electric current to the electric motors of the two upper centr4 fugal blowers 18 and to the electric motors of the two lower centrifugal blowers 15 when the internal temDerature of the closed suace 15 in the casing 81 is not lower than the lower-1-imit temperature (e.g., 0: C), the centrifugal fans start operating. As a.-esult, a ir (clean inside air ----u ating flow of a high-temperat-,:re a --f 2-5 or inside fluid, not containing any foreign material such as dust or moisture) is formed within the closed space 9 in the cas-'nc; 81. "ilso, w4;.thin the low-temperat,.:re-side heat transfer -175- space 12 cuts-Lde the casing 81 a circulating flow of a low-temneratu_-e air (outside air, or outside fluid, not contain_ng anv foreign mater 4 al such as dust or moisture) Js forme,4 7n e;-zc- of the plural stages of cooling apparatus1 mcunte-_ -_'-_rouah the flu'Ld seDarat.J_nc 7,late 2 of the casinc: 81, the sealed -'n the refricerant tank 3a is boiled and vapor--7- e v being exposed to heat which '",as been transferred from 7-.-e hah-temrerature air through tte heat receiving fJ_rs I - :7or4 fr4 6 a z ec r e -gerant is condensed on -he inner wall su--faces of" the condensing portion 31: which is at a low -emnera-_-,:re]Dv '_-ei-g ex-,:osed to the low-temQerature air. The resul-zInc: la-::en-- neaz of condensat-I'cn is transferred tc tne 7ow-t=cerature air through the radiatina fins 6b.

The refrigerant thus condensed in the condens-'ng ::)ortion 3t drczs alonci the inner wall surfaces of the low temoerazdre-s_4de comm-unication pipes 34a into the refrigerant tank 'a- _,:e --o its own weicht. Thus, the -refrigerant 8 se-aled in the hea-: absorbing tubes 31a of the refrigerant tank 3a reneat-s '-o_'Iing and condensation alternately, that is, the heat C..-ah-temnerature air is --ans-cerred to the _cw-te=e_-a-_'.:re air, so that the he-=-- cenerated from -he narts car be re--Ie-;--se,--; in the plural stages of coc-1-4-a aznara-_-_,s 2 Consec,,aentiv, -the electronic parts 7 can be cocled w-'thc7-- -: a ariix-:ure o-f the high-t emperazure a4L-- 'clean ai-- within the casna 81) wh' '_ _C'. circula-:es -,.i i r h in the h i c: l-, - --76- temperature-side heat transfer space 11 in the closed space 9 and the low- temperature air (foul air outside the casing 81', which circulates within the low-temperature-side heat transffer space 12.

Next, an effects of this embodiment will be described.

In this embodiment, the refricerant tank 3a, condensinc portion 3b, low-temperature-side communication pipe 34a and high-temperature-side communication pine 34b can be eas4L I v connected mechanically and hermetically by using the un-Lon 7_7 and nut 70. in other words, the number of mounting steps can be greatly decreased, and therefore it is possible to prevent deterioration of the mounting performance for the flu_i'-_ separating plate 2.

Besides, since the refrigerant tank 3a, condensing portion 3b, lowtemperature- side communication pipe 34a and high- t emperature-s ide communication pine 34b are simply and mechanically connected, even when one of the refrigerant tank 3a and the condensing portion 3b needs to be changed, it is possible to easily change one of these with a replacement par-_.

That is, even in the case where a cooling apparatus not. hav4Ln-.

a o_-edetermined level of airtightness is included among a plurality of cooling apparatus in the checking of air-Lightness it is poSS4 after being assembled,.i-ble to change or repair suc a cooling apparatus easily.

In this embodiment, the followinq additional effects can be also obtained.

1) At the time of connectJ;-na the low- and high- -177- temnerature-side communication pipes 34a and 34b with the refrLueran-z tank 3a and the condensing portion 3b, it is possible to omit the heating step; and therefore, it is possible to prevent a chance of the product size due to heat dist--r-::-Jcn (deformation) as well as deterforazion of durability due by a res-4dual stress.

S'n 'ow ce a olura7ity ol holes through which the and '--------e=erature-s4de communication p4pes 34a and 34b pass are L-r7,.e--4 -'n the -Eluid separating plate 2, it is possible to imprcve -i'-e a4-t4chtness and waterDroofness between the fluid sepa-ra-L--ng pla-Le 2 and the low-temperature-side communication pipe 3-1-'t. - 7 n this embodiment, the cool-'n.a apparatus 1 in three-Szage-= is used; and thereffore it is necessary -to use three 11cq-temnerature-side ccmmunicatio.- nines 34a and three high-7-emperature-side communication pines 34b. As shown in FIG. 88, the low-temperature-side communication pipes 34a are disniaced from one another. Though not shown, the high temzera-r---,:re-side communication pines 34h are also displaced from one another. With this arrangement, even when nuts 70 (whi--,.-- w--.71 he described later) are formed, the nuts do not inte----ere w-'-!--h each otter, and it is possible to minimize the size in tne lam-ina---4ng direction, theretv downsizinc: the -,e re---aeranz tank 3a 'n-,u,ies the olural e;::; 2 5 ahsor!DJ--- 31a d-soosed subs tant ial]-v in parallel wi t- h each t"e 'neat abso--:)-:iicn-s4I--d-- lower ccmmunicaz4I-nc r)Crt-= 41 locat-e2!Delcw -L-,e heat abscr-'-ing tubes 31a communicates the tubes 31a with each other, and theheat absorption-side upper communicating portion 42 located above the heat absorbing tubes 31a communicates the tubes 31a with each other. A communication pipe is disposed substantially in parallel with the heat absorbing tubes 31a and is in communication with the heat absorption-side lower communicat-ing portion. Therefore, it becomes possible to downsize the cooling apparatus 1.

(4) Since the heat receiving fins 6a and the radiating fins 6b are attached in a fused state to the refrigerant tank 3a and the condensing portion 3b, respectively, it is possible to diminish the thermal resistance between the f ins and the cooling tubes as compared with the case where the fins 6a and 6b are attached mechanically to the refrigerant tank 3a and tne condensing portion 3b, respectively. As a result, the whole of the cooling apparatus can be further downsized as compared with such mechanical connection.

(5) Since the gas which has become at a high te.,nDerature due to the heat generated from the heat generating elements 7 is introduced smoothly into an air --':low path through a vent port 13, it is possible to maintain uniform the internal temperature of the closed space 9. More particularly, S 4 nce the gas which has become hot by receiving the heat from the heat generating elements 7 rises within the closed space 9 hy 2 the convection, preferably the vent port 13 should be formed in the upper portion of the closed space 9 to improve the cooling e-ffLciencv in the closed space 9. In other words, when the - 179- vent z)or-- 13 is formed in a position lower than the fluid separating plate 2, a -relatively low-temperature of gas in the closed S-Dace 9 is introduced into the air flow path 23 through the vent 1-3 and is led to the refricerant tank 3a, the Cooli-a e 4 4,=nC-,, in the closed space 9 is not sufficient.

in this embodiment, moreover, the whole of each cool-= azci:)aratus 1 -is disposed in a loncitudinally (trans- 90) while being inclined so that the gases verse in F7 C_.

mass= the --efricerant tank 3a and the condensinc:

nortLian 3'-- in --', e hich and low- temperature-side heat transfer spaces 11 and 12 flow smcothiv from suction-side vent ports!3 and 16, tc-, ;ard ex'naus-:-s'Lde vent ports 14 and 17, respectively. Tnerefore, --he change in the flowing di-re-c--ions of the c-=s passing through the refrigerant tank 3a and the condensing oortion _--b can. be slackened and hence 1"t is possible to decrease the loss of air flow path in the narrow spaces. As a result, the fans 15 disposed in the closed space 9 can be downsIzed, and -further the calorific value of the fans 1-5 can be decreased. Therefore, the amount of heat generated from the 4 heat =enerat4ng elements 7 can be _ncreased as much as the S4 reduCe-' c-m-lorif] _c value (tInat is, the -,':ans 113 is large- _Lzed - to increase coo'inq capacitv, the calor44c value of the fans 15 increases; as a res7dlt, the amount of he_at- generated from --he I-e-=-:: zenera- Lina elemen-zs 7 Cannot be increased).

-embodiment of- the cresent invention w__'_', '-e descr_4be-d below. he ccnstructJon of the coc-lina apparatus according to this embodiment is the same as that of the twenty-fifth embodiment except the connection between the low temperature-side communication pipe 34a or the high temuerature-side communication pipe 34b and the re-fricTerant tank 3a or the condensing portion 3b. Therefore, the connection portion in this embodiment will be described.

In this embodiment, the connection between the low temperature-side communication pipe 34a and the heat absorption-s.J-de lower communicating pcrt4 on, the connection between the communication pipe 34a and the radiation-side lower communicat-ALng portion 43, the connection between the high temperature-side communication pipe 34b and the heat absorr)tion-side upper communicating portion 42, and the connec tion between the communication pipe 34b and -the radiation-side upper communicating portion 44, are of substantially the same structure, only the connection between the low-temperature-side communication pipe 34a and the heat absorption-side lower t 4 communica _ng portion 41 will be described.

FIG. 91 is a cross sectional view of a connection in this embodiment.

Th4_s connection between the low-temperature-side comm,unicatLcn pipe 34a and the heat absorption-side lower communicating portion 41 is structured of a union 71 and a nut 70. More specifically, the union 71 is constituted by a 2 5z tubular member Joined integrally to the heat absorpt'Lon-side lower communicating portion 41 in communication therewit.h. The port'Lon of the union 71 on which the nut 70 is fit-ted is _181- reduced Ln outer diameter and the front end of the union 71 is tapered. The contact portion of the low-temperature-side communication P-;De 34a with the union 71 is widen and contacts with the tacered end of the union. The nut 70 is fitted on -he 4 reduced-rdiameter portion of the union 71 and b-lases the ccmmunic_;z-:_-cn ziDe 34a toward the front end side cf the union 71 so as ---- herme-r_- ica-1.1v connect therebe-r--ween.

Zilsc _n tillis embodiment, as in the twen-Lv-fi-;'---"h emb o d 4 7, 7, the ref r --cerant tank 3a, condensing portion 3b, 7 0 --ure-side communication pipe lcw--==er=i_ 34a and hiah temnerature-s-4--4e communication pipe 341D can be easily connected mechanical I,; and hermeticall1v by using the union 71 and the nut t 7 V 70. TI-iaL_ S, the number of mounLinc s at4 decrease.-d and hence it is possible to prevent deterior -on of the mcun.t-'nc oerformance for the fluid separating plate 2.

Since the refriaerant tank 3a, condensing portion 3b, and low and high-temperat-ure-side communication pipes 34a and db are c3nnected si-moly and mechanically, even when one of the refricerant tank 3a and the condensing portion 3b needs to be chanced, L't is r)oss]-ble to easilv cnanae one of these with a replace-menz part. That is, even in the case where a cooling a-parazi-,.S nct naving a predetermined level of airtightness is 4 _ncluded; amona a plurality of cooling apparatus in the checking of after beinc assembled, it is:Dossihle to change or re=a-i-sl--c- a coclina az-aratus eas"!V.

_klt-cuch in the above em-todiments the condensina portJLon 3b is -formed substantially just above the -re-f-r-Jigerant -182- tank 3a, both may bedisplaced from each other as in FIG. 92.

Moreover, it is not always necessary for the condensing portion 3b and the refrigerant tank 3a to be disposed on the same plane. For example, the condensing portion 3b formed above the refrigerant tank 3a may be inclined (for example, orthogonal) (not shown) relative to the refrigerant tank 3a, and the positional relation may be altered according to the shape of the housing used. In this embodiment, since the connection between the low-temperature-side communication pipe 34a or the high-temperature-side communication pipe 34b and the refrigerant tank 3a or the condensing portion 3b employs fastening members (union 71, nut 70, and the like), it is possible to modify the installation shape easily. Besides, as compared with the case where the refrigerant tank 3a or the condensing portion 3b and the communication pipes are integrally connected together beforehand, a storage space thereof can be reduced.

Further, it is not always necessary for both the connection between the low-temperature-side communication pipe 34a and the refrigerant tank 3a and the connection between the communication pine 34a and the condensing portion 3b to be connected according this embodiment, at least one of the two connections mav be connected according to this embodiment. in the same manner, at least one of the connection between the high-temperature-side communication pipe 34b and the refrigerant tan.k 3a and the connection between the communica tion pipe 34b and the condensing port'Lon 3b may be connec--ed -183- according to this embodiment.

Although the present invention has been fully described in ccnrec-:icn with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various cnan-es and modifications will become apparent to those skilled -'n the art. Such changes and modifications are to 6e understoc--4 as being incluled within the scope of the present invent-4c-. as (effined in the appended claims.

-184-

Claims

I A cooling apparatus using boiling and condensing refrigerant, for coolin2 a heatina element, said cooling apparatus comprising: a refriaerant tank for containing, a refrigerant which is boiled and vaporized by receiving heat generated from said heat element; a radiator for cooling, and liquefying the refrigerant which has been C In vaporized in said refricerant tank; wherein, C) said refrigerant tank includes: a vapor passace through which the refrigerant having been vaporized by receiving heat from said heating element flows out and a condensed liquid passage into which the refrigerant having been condensed and liquefied in said radiator flows, said vapor passage and said condensed liquid passage being in communication with each other at the ZO C respective lower portions; and a heat decreasing structure provided between said vapor passage and said condensed liquid passage, for decreasing an amount of heat transferred from said vapor passage side to said condensed liquid passage side.
2. A cooling apparatus according to claim 1, wherein said refricrerant ID I= tank includes a heat insulating passage formed between said vapor passage ZD Z__ and said condensed liquid passage as said heat transfer decreasing, Cn C structure. an interior of said heat insulating passage being filled with the refrigerant.
3. A cooling apparatus according to claim 2, wherein inner fins are ided in said heat insulating passage.

provi 1 1 Z_
4. A cooling apparatus according to claim 2, wherein said heat z:, insulating passage has an inner wall surface formed in a concaveconvex shape.
5. A cooling apparatus according to any preceding claim. wherein said refrizerant tank has a support wall portion for partitioning between said vapor passage and said condensed liquid passage, said support wall portion having a constricted part of a reduced cross sectional area as said heat C transfer decreasing, structure.

Z:
6. A coolinc, apparatus according to any of claims 1 to 4. wherein said refriLyerant tank has a support wall portion for partitioning between said vapor passace and said condensed liquid passage, and air-cooling fins as 186 said heat transfer structure are formed outside said support wall portion.
7. A cooling apparatus according to any preceding claim, wherein said C refriaerant tank is constituted by an extr-usion member which is produced by extruding Z
8. A cooling, apparatus using boiling and condensing refrigerant, for coolina a heat element, said cooling apparatus comprising:

ZD a refriaerant tank for containing a refrigerant which is boiled and Z__ C) vaporized by receiving heat generated from said heat element-, and a radiator for cooling and liquefying the refrigerant which has been vaporized in said refrigerant tank; C wherein said refrioerant tank includes:

C a vapor passage through which the refrigerant having been I-D vaporized by receiving heat from said heating element flows out; t Z- a condensed liquid passage into which the refricrerant havinor been Z C condensed and liquefying in said radiator flows, being, adjacent to said vapor passage and beinor in communication with said vapor passage at the I lower portions; and a heat conduction suppressing passaore arranged between said vapor passage and said condensed liquid passage and having a refrigerant inlet I'D 187 for introducina the refrigerant to said heat conduction suppressing passage C C at the lower portions.
9. A cooling, apparatus according to claim 8, wherein:

s'd refriaerant tank has a partition member therein for partitionino, al said refriaerant tank- to said vapor passage and said condensed liquid passage, and said heat conduction suppressing passage is arranged along said partition member in said refrigerant tank.
10. A cooling apparatus according to claim 9., wherein said condensed liquid passage and said heat conduct' Cr rA 1:1 ion suppressing passage are arran ed at one peripheral side in said refrigerant tank- than a heat element mounting portion at which said heat element is to be mounted.

ZI.ID
11. A cooling apparatus according to claim 8. 9 or 10, wherein said heat conduction suppressing passage has a predetermined width equal to those of said vapor passage and said condensed liquid passage.

I A cooling apparatus substantially as described herein with reference to Fi-s. 14 to 25 of the accompanying drawings, at least.

188