CA1264126A - Dual volute molten metal pump and selective outlet discriminating means - Google Patents
Dual volute molten metal pump and selective outlet discriminating meansInfo
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- CA1264126A CA1264126A CA000477632A CA477632A CA1264126A CA 1264126 A CA1264126 A CA 1264126A CA 000477632 A CA000477632 A CA 000477632A CA 477632 A CA477632 A CA 477632A CA 1264126 A CA1264126 A CA 1264126A
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Abstract
DUAL VOLUTE MOLTEN METAL PUMP AND SELECTIVE
OUTLET DISCRIMINATING MEANS
ABSTRACT
This invention relates to improvements in molten metal pumps for the transfer of principally molten aluminum and zinc from specialized molten and holding furnaces through fluidics control means downstream of the pump to control the direction of flow of molten metals at 1200° - 1600° tempera-tures.
The molten metal pump is characterized by both upper and lower dual volute pumps driven by the same shaft, each having separated intake filtering means adjacent the top and bottom of the pump unit. Separated and extended molten metal intake means permit molten metal flow from a submerged environment through restricted peripheral ingress slots both about the top and bottom and into both top and bottom independent voluted pump impellers, The invention permits direct use of the novel pump with aluminum metal, whose oxide impurities settle and/or zinc metal whose oxide particles float, in the molten state without pump modification.
Separate dual peripheral filter ingress zones lead into separated dual volume pumps removing hard particulates suspend-ed in the melt, illustratively; spalled fire brick refractory chunks, scraps of unmelted metal and other foreign inclusions from causing excessive wear and tear or total destruction of the interior volutes and their related impellers of the pumps.
The combination of the so-improved pump in cooperation with the divergent stream transition control provides an im-proved portable means of selectivity of one egress means out of two diverging exit channels through molten metal flow control means remote from the melt.
OUTLET DISCRIMINATING MEANS
ABSTRACT
This invention relates to improvements in molten metal pumps for the transfer of principally molten aluminum and zinc from specialized molten and holding furnaces through fluidics control means downstream of the pump to control the direction of flow of molten metals at 1200° - 1600° tempera-tures.
The molten metal pump is characterized by both upper and lower dual volute pumps driven by the same shaft, each having separated intake filtering means adjacent the top and bottom of the pump unit. Separated and extended molten metal intake means permit molten metal flow from a submerged environment through restricted peripheral ingress slots both about the top and bottom and into both top and bottom independent voluted pump impellers, The invention permits direct use of the novel pump with aluminum metal, whose oxide impurities settle and/or zinc metal whose oxide particles float, in the molten state without pump modification.
Separate dual peripheral filter ingress zones lead into separated dual volume pumps removing hard particulates suspend-ed in the melt, illustratively; spalled fire brick refractory chunks, scraps of unmelted metal and other foreign inclusions from causing excessive wear and tear or total destruction of the interior volutes and their related impellers of the pumps.
The combination of the so-improved pump in cooperation with the divergent stream transition control provides an im-proved portable means of selectivity of one egress means out of two diverging exit channels through molten metal flow control means remote from the melt.
Description
T~IU 2-001 DUAL VOLUTE MOLTE~l METAL PUMP AND SELECTIVE
OUTLET DISCP~rMI~TION ME~NS .
BACKGROUND O~ THE INVENTION
This invention provides over-all means for circulation of mol~en metals under a substantially constant head of pressure and flow rate in a substantially laminar flow downstream of the egress of the pump whlch 1~ adapted for use submerged in a meleing/holdin~ furnace.
I~ further provides a control ~eans fsr direction of a selected one of two downstream egress chann~ls wi~h molten metal by ~eans o combination of the molten metal pump in downstream co-operatlon with a downstream flow selector means for said ~election of any one of the said two channel means, said flow selector means preferably integral with the single output orif$ce of the molten metal pump.
The selector means may also be operated independently physically as a separated unlt down~tream of a prlor art pump or a gravity fed source of molten metal ch~racterized by havin~ a cons~ant pressure head and flow rate as might originate from molten flow into a tundish placed in a holding furnace on an upper foundry floor, without integral connection with a pump, the latter operations are no~ often feasible and limit foundry flexibility in moving molten metal from one furnace to another, or from one urnace ~o two or more ~eparated down-stream operations.
By mean~ of the preferred combin~tion, one may feed a single metal flow se~uentially to one of ~wo or more operatlon~.
~etal may be sequentially cast, for example, rom a molten Rupply into various downstream operations producing ~o.lid ~et~l, TH~ 2-001 ~L2 ~
forms such as lngots, sheets, foils, tubes or rods, etc,.
by use of one unit fluidic control or a ~lurality of said wnit controls in serie~, if desired.
Both soluble and insoluble zross solids includin~ fluxes, sla~, unmelted metals includinz iron, silicon, etcO, fire-brick refractory fra~ments, aluminum oxide occlu~ions, etc., which can damage the downstream volute pumps accumulate upon normal handling of molten metal in refractory urnaces and tend to collect upon and af~er formation in meltin~ and hold-in~ furnace~. As the foregoing partlculate lmpuritic~ native to handling molten zinc are inherently lighter and ~end to 10at, they tend to be drawn into top fed impeller pumps, Hence, for handlin~ molten zinc bottom fed pumps are normally selectedO On the other hand, with molten aluminum and its alloys, occluded impurities are most often heavier than the melt and tend to agglomerate and settle. Liquid aluminum metal fed into bottom-fed volute-impeller pump~ have been generally avoidedO
The prior art has su~gested multiple specialized molten metal pump a~semblies by use of alternative pump elements, including drive shats, pump impellerg as illustrative. Shorter drive shaftq have been used where top eed of molten aluminum metal to a top fed impaller pump i~ desired. If metallic zinc was to be handled, a longer drive pump shaf~ and co-relatsd inverted cup impeller fed from a bottom in~ress pump was assembled. Pump as~emblies ha~e been 80 designed as to provide bottom fed molten metal pUmp8. See Swaeney et al., U.S~ Patent 3~048/384~
One prior ar~ solution has proposed a system of rota~y baffles, referred to ag "deflector disks", driven on the same ~ THU 2-001 ~æ~L~z~
vertical drive main pump shaf~ provided controlled circum~er-ential clearance of molten metal from the meltin~ furnace by ~djustment of the dl~k clearance on the common drive shaft both above and below annulAr top and bot~om fed sinzle pump ingress means. See Sweeney et al., U.S. Patent 3,291,473.
llere, a volute pump has been described to be useful to pump molten metal inwardly through a single pump ingre~s mean~
ed from the top. However, a slngle pump impeller devoid of volute m~an~ is employed.
I~ should al80 be noted that in the top and bottom entry modifications, patentee does no~ u~e a volu~e pump and the utility does not permit ~he higher temperature~ e~sential in handlin~ mol~en me~als and i~ intended for generally lower t~mperature melting point chemicala. In either case, entry is through and pa~t rotary, driven, de1ector disks slightly upstream of ~he m~tal flow entry lnto the pump.
It is well known, however, that similar rotary power drlven disks spinning within an encloged cle~rance provlde hi~h shear dispersive forces. The high ~hear rate produced effects unwanted dispersion of forei~n matter as referred to above which contaminates the melt stream. Rotary di~per~ion action of the described classifiers tends to defea~ the filtra~ion intended and to break up and disperse in~oluble solid matter.
Here, dual volute pump~ opera~ing from a single shaft separately xeceive influx o molten metal whlch flrst is fil~ered of all su~pended ~olid~ ln the mel~ by ~n upper and lower restricted ingress zone co~pletely about the perlphery of the submers~ble pump which lnsures that the pump clearances are not unduly worn or damaged by entry of any one of the foregoing ~nmelted accumulated particul~t~s.
One prlncipal advance over the prior art herein dlsclo~ed i~ embodied in th~ moving part~ free, selective fluidics flow control means, particularly when operated in conjunct~on with the dual ingre~s dual volute pump, both of which are more fully described herein~
The liquid metal flow upon egres~ from the pump and enterin~ the downstream transition control mean~ i8 control-lably dlverted into a selected one of two diver~ent controlled downstrea~ condults or channel~ without interference wlth over-all through~put flow rate.
Commonly the principal control of molten metal flow egressing the pump has been solely through control of the pump operation. The limitation has been ~rimarily an on-off; flow or no-flow; operatlon where the driving motor means control of resultant metal flow through the pump i8 not in~tantly re~ponsiv to the "on-of" si~nals.
~ en ~n "on-off" flow con~rol 18 employed in a moving s~ream of metal, particularly, a "water hammer" develops which is detrimental to the pump function and may cause breakage of the graphite part~ required in the pump manuf~cture, This invention makes possible downstream selection of alterna~ive meltln~ and holding fu~laces and re~circula~ion within and between such furnaces and alternative delivery of a single 3tream of molten metal ~9 one of ~wo pre-selected downstream operations.
The fluidic~ devices of this lnvent~on oan be used in tandem in plural number, if deslred~ makin~ continuou~ oper2-tion from a single melting furnace, or a plurality of mel~ing or holding furnaces feeding a ~eries of varying downstream operations el~ctively and sequen~ially.
T~U 2-001 ~2~ %~ 1 S~ ~ RY OF THE INVENTION
The invention as herein di~clo~ed provides a fluidics operated molten metal flow control device operable downstream of a melting and/or holding furnaee under a relatiYely constant ingress head and laminar ~low rate. Under the foregoing condl-tion~, a fluidics controlled transition zone controls flow of a single upstream enterlng vo'lume of liquid molten oetal into one of two downs~ream alternative bifurcated egres~ channel~.
The dual channel~ outwardl.y diverge from one another at an acute angle forming interiorly thereof the basic position of solid conjoined trian~ular splitter element to be affixed thereon.
The acute angle of the splitter elemen~ exte~ds up~tream and ori~inates the demarcation point of internal stream flow divlsion~ The division apex line defines the ori~in of the outwardly diverglng channel~ downstream of ~he splitter and physically extends operably u~stream into said transition zone volume.
Upon pas~a~e of a single molten metal stream into the upper in~ress or opening lnto sai~ transltion zone, the single stream is diverged into a selected one of the ~wo divergent downstream outlet channels bu~ directed in a single ~tream through a common and expanded volume sometimes referred to herein as the tranBition zone and one slde of the spl itter in a pre-selected downstream channel, The fluidics control zone tran~itiQn piec~ integrally join~ the ~ingle up~tream en~ry channel through a transition zone of expandin~ vol~me, split by the leading acute an~le ~d&e o ~ splitter elsm~n~ partially intruding up~tream lnto _5_ , . . .
. .
~,, the aforesaid ~ransi~ion zone but downstream to e~tablish the inner walls of the two divergin~ bifurcated channels. The downstream outwardly bifurcatin~ ~in~le channels of the transi-tion æone are herein referred to for convenience as conduits or channel~ A and B. Corresponding stream~ flowing through said channels are corre~pondin~ly referred tO a~ stream A
and s~ream B.
Only one selected stream (A or B) flow~ through a corre-sponding downs~ream channel (A or B) und~r a Eiven flow control at any one time.
The specifle design of the fluidic~ control transition zone and its co-operative elem~nt~ can be specifically modifled to meet required ends for specific operations and demand condi-tlons.
One modification of the ~ransition control ~one permit~
a Eail #afe operation 80 that flow of stream B through conduit or leg B, for example, establishes that stream B will dominate (unle6s manually over-ridden).
To operate thereafter through conduit A, the remote control device must be set or fixed in operatin~ position to re establi~h and maintaln an elected flow pattern through non dominant leg k. Stream opera~ion through condult B will be resumed automatically upon relea~e of the control o~herwise directing ~he mol~en stream ~hrough channel A~ ~See Figure 7.) In another, pos~ibly preferred, metastable ~ode of opera-tlon the ~ransi~lon zone i8 as 8hown in Figure 6. Here, both eonduit A and ~ream A, or conduit B and stream B only require appropriate in~ection of a puff of compressed g~8 from the remote control ~o effect input of a controlled jet of eon~rol ..
stream gas into the appropriate control orifice and into and upstream of the transi~ion zone to imping2 upon the po"er stream to convert the stream flow from channel A to channel ~, or vice versa.
Initlal de~ign of the fluidic~ controlled transi~ion zone may restrict the cro3s-sectional area of one selected channel or le~ A or B.
l~ile it is possible to devise the cross-sectional patterns of the channels immediately upstream of, wi~hin, and downstream of the transition control including ~he single immediate ingress as may be illustrated elsewhere, it is preferred ~n the best mode of practice known, tha~ the cross-section be of ~enerally slliptical form wherein the major axis i8 vertical, as 19 illustrated in Fi~ure 8.
Such sectional control assists in maintaining laminar flow and optimum practical use of the"Coanda" or "wall effect".
O~her modifications are within the knowledge o ~he fl~idics art. Other po~sible control modification~ are not precluded, however, In the preferred form of the invention the molten me~al pump is constructed upstream and integrally a part of the downstream ingre~s control channel and metal stream into ~he single entry passageway of the downstream fluidics control transit~on zone.
While the pressure head and flow control conditions essential to functional operation~ of a fluidics control and ~ransition zone means may be established in theory and prin-ciple by gravity flow from an elevated source of supply of the required molten metal, su~h means are not amenable to ~aried plant conditlon~ and opera~ions. Operations are then limited to sin~ular and unlque posi~ions and location~
within specialized building structure~. Fur~her, in gravity operation speclal efforts may be necessary to assure the fluidic~ control unit be supplied with auxiliary heat to prevent (or to re-mel~) metal freeze-ups when the ~r~vity uni~ i8 forced to be shut down unexpectedly.
While a compre~sed ~as useful in operating the transition control zone i~ usu~lly ~n inert ~as, lllus~ratively nitrogen, in somR ln~tances minor percenta~es of usefully reactive ga~es, i11ustratively chlorine and/or arg~n, etc.~ may be blended into the control gas stream as an aid ln maintaining pur~y of the molten metal.
Impact of the pressurized control ga~ stream interiorly of the transition zone below the initial ingress point and upstr2am of the splitter initiates turbulence and development of a gas bubble. The development of a "separation bubble"
initiates the e6sential destruction of the existing "Coanda"
or "wall effect" and momentary ~tream flow ins~æbility within the transition zane a However, as the de~tabiliz~d ~tream flows close to the alternate and dlver~ing wall the "wall effect" brings the molten metal ~re~m lnto the alterna~ive and diverg~ng bifurca~ed downstrgam leg. This completes a directional flow change over and into the selected, alternate, downstream ehannel or le~ as defined by the splitter apex permanently locat~d in the enlarged volumc fur~her downstream and interior of ~he expand~ng transition plece volume.
The dynamic energy content inherent in the molten metal power s~ream cour~ing downstream from the pump (or head) i~
-~L~,~..~
~he principal source of energy in the fluidic dynamics of the fluidica flow directional control unit d~scrlbed herein, A ~econdary compres~ed gas control stream originating at the remote control point provides the ancillary ener~y source essential ~o efect growth of the separation bubble and destroy the pre-e~tabli3hed w~ll effect~ The compre~3ed ~as power ~tream i8 30metime~ referred to a~ the ~econdary control gas ~tream.
So far as i8 presently know~, movemen~ ~nd transfer of mol~en me~als and control o flow ha~ been principally u~eful in lncreasing and su~taining produetion of castings~ sheet, foil, etc~, by ~speclally de~igned m~lten metal pumps prin-cipally con~tructed of ~ refractory non-metal, most often ~raphite, to withstand the elevated temperatures, erosion and ~orrosion due to movin~ contact with molten metal at temperature~ illustratively from about 1200 to 1600F at a choice of several downstre~m plant operations. . .
Only two pumping conditions were previously controlled.
The power source, compressed air or a long shaft directly driven electrlcal motor~ could be "off" or "on". Molten metal flow either "stopp~d" or being actively pumped from with~n the melting furnace down~tream thereof~
Molten pump ~ailures prgsently most oten occur during sear~ up or ~hut-down due to sudden flow rate chan~e~.
Hammer effects when a pump i8 ~urned "off" develop severe ~trains in the pump and wear through reduced clear~ce~ within the pump i8 a~celerated. Wi~h the pre~ene combination of pump and re te control means as~ociated, and preferably integral therewith, pump ~hut-off to con~rol flow i~ no long2r mandatory, ¦ THU 2-001 '~
Use of optional forced melt circulation within the mek in~/holding furnace, now made ~ractica~le~ has se~eral advan~a~es, The time nQcessary to prepare a melt may be ~hortensd. Development of metal oxide~ and other impurities wlthln the melt h~ le6~ time to be produced due to increa~ed meltin~ rate wi~h forced circulatlon of the melt over the ~olid 3urfaces. Meltin~ o~ ~olld metal scr~p i~ poasible at hi~her furnace turnover ra~e if the ~hear rate of movement of the liquid pha~ over the solid scrap ~urface~ during melting periods i8 enh~nced.
However, known material~ and means useul to ~hange direction of flow which ch~nge~ shear rate~ B~ the molten metal powers~ream i8 either throttled down~ as in stopping, or increa~e~ in ~hear, if starting up. This action occurs in prior art valves depending upon moving parts to throttle moving stream, a~ illus~rative.
Known valve~ are not adaptable to the control of high temperature lten metal stream~, permitting as illustrativ~, an alternative pumping circulation pha~e within the melt~ng furnace and a second egre~s phase where the prepared molten metal is delivered to a point of u~e apart from the melting furnace.
A~ indicated above, molten metal - air (oxygen~ contact mu~t be avoided wherever po~ible becau~e of the high oxida-~ion reaction rate (of aluminum and oxygen~ and con~equent loss of useful m~al due to the r~pid ~ormation of in~oluble contaminating heavy aluminum oxide par~icle~, aB i8 well under~tood, Thie invention prov~de~ a ~ovel mean~ of co~trol o~
the fl4w of molten metal ~hrough ~elected and alt~rnatlve channels or conduit mean8 without corrosion or wear upon the surace of moving control valve6 designed to chan~e rates of flow and thereby undergo wear. Change in flow directions into one of ~wo el~c~ed flow path~ as i~ accomplished herein without materially interruptin~ the normal flow ra~e of th~
princlpal or "power" molten metal ~tream h~s not been hereto-fore known.
In the utilization of the fluidic~ controlled transltion ; control mean~ of this invention the requiremen~s of standard-lzed pres~ure, flow ra~e and ~he laminar flow character of the stream are ~mportant to the dependable operation of the device.
In use, the pump ~ssembly a~ herein described is sub-merged in molten metal. Molten ~etal enters ~he upwardly extending central cup of the top volute pump by pa~sage through ~, an extended controlled molten metal clearafice zone or volume which provide~ effective filter m~ans. The extended filter zone is created by means of an extended ~pecial ingress volume defined by the dual top horlzontal spàced apart plates of the I pump assembly ~hrough which top llquid entry occur~ and a i like bo~tom ingres~ zone created by spacer feet between the interior flat bottom of the furnace and the bottom horizontal plate o the submerged p~mp baseO Note th~t bo~ the en~ire periphery o ~he pumpj bo~h bop and bo~om, d~fine ~ filtra-tion zone ingress means lnherent whe~ the pump i~ in uAe These clearanee entry 810~8 or filtxa~ion ~lements a~sure absence of in801ublc accretions in ~he incom~ng mel~.
Fu~ther, a~ the vol~e of ingres~ liquid entering the pump ori~inate~ over bo~h top and bottom of the pump per~phery, dL~DYtd2~;
thu~ the developed ~hearing 8tre89 i~ insufficient to disinte-grate occluded insoluble "tramp" material~ commonly contamina-ting a molten metal durlng ~elting, holdlng and transfer.
~hunk~ of refractory brlck, undi~solved 8illcon meta~,,oacluded insoluble metal oxides, e~c., cause at best e~ce~sive wear, and more often abrupt breaka~e of pump part~ which are at close tolerance~, Carry ~hrou~h of in~oluble metal oxlde aCcretionR i8 not only ob~ectionable in proce~sing m~lten m~tal~ but insoluble metallic impuritle~ in the mel~ if not removed downs~ream, are a cause or reie~tio~ of co~pletely formed metal part~ and useful product~ derived therefrom.
The. disclo~ure herein com~rises two clo~ely related inventive entities most often in advantageous functional combination, but e~ch of which can be operated separately, but always ~dvflntageously arranged in series compri~ing the improved molten metal pump and the correl~tive downstream control mean~.
The principal novel entity in the combination comprises a molten met~l fluid flow ~irective control device dependent for itB operation upon a reliable ~ource of molten metal flow.
~elatively con~ant flow rate, constant pre~sure head and freedom from occluded insoluble particulate~ And es~entially laminar flow are derivat~ves essential and dependent upon a qu~lity molten metal p~mp upstream of the said control.
The flow control device of this inventive combination is charac~erlzed by a ~in~le fluid ingress channel, dually diver-gent blfurcated egres~ channela down3tream and intermedlately of ~aid single ingress andl the b~ furcated egras~ ch~nnels a ~¦ THU 2-001 ~L2~i~%~
fluldlcs ~ontrolled transition zone, 3 stream directing exit orifice t~rminating said sln~le ingreas mean~ down~tream of : sa~d e~r~s and entering said transition zone, oppositely dispoaed inwardly directed pressurized ~as control ports adap~ed to control dlfferential ~as pres~ure3 interiorly of said egress zone At said exit oriice, said transltion zone expandin~ ln volume downstream to ~ccommodate ~ sln~le enlarged entry zone in~o ~aid dual bifurc~ted downstream egress channels which channels separate and diverge at an acute angle 7 interl-orly thereof iB et a conjoi~ed ~olld triangular splitter element the apex of which ex~end~ upstream i~to the downstream terminus of ~aid expanded transitlon zone volume; said diagonally opposed ~as pressure control ports upstream in the transition provide control from a remote poin~ of origin of said essential pressure controlling gas ports~
The pump so~rce specifically referred to above of a m~lten metal flow having relatively co~stant lamin~r flow rate, pressure head and freedom from "tramp" particulate solids is preferably operated in inte~ral combination wi~h the fore-goin~ fluidlcs molten metal flow control device. The~e separately and dual function~, but preferably physically unitary elem~nts, comprise in combin~tion a uni~axy molten metal pump with selective directional output control means downstream thereo~, The comb~nation assembly provides inter-relating and inter-related lmprovement in the handling of refractory molten m~tal by f~nctional immers~on in mel~ng/
holding furnaces.
,, /
I ~
BRIE~ DESCRIPTION O~ THE DRAWINGS
Fi~ure 1 is an elevatisn partially in sectlon not2d with parts broken away of a molt~n metal pump in operative ~ association with a ~olten metal bath or mel~ing furnace~
: Figure 2 is a psrtial se~tional view along the line
OUTLET DISCP~rMI~TION ME~NS .
BACKGROUND O~ THE INVENTION
This invention provides over-all means for circulation of mol~en metals under a substantially constant head of pressure and flow rate in a substantially laminar flow downstream of the egress of the pump whlch 1~ adapted for use submerged in a meleing/holdin~ furnace.
I~ further provides a control ~eans fsr direction of a selected one of two downstream egress chann~ls wi~h molten metal by ~eans o combination of the molten metal pump in downstream co-operatlon with a downstream flow selector means for said ~election of any one of the said two channel means, said flow selector means preferably integral with the single output orif$ce of the molten metal pump.
The selector means may also be operated independently physically as a separated unlt down~tream of a prlor art pump or a gravity fed source of molten metal ch~racterized by havin~ a cons~ant pressure head and flow rate as might originate from molten flow into a tundish placed in a holding furnace on an upper foundry floor, without integral connection with a pump, the latter operations are no~ often feasible and limit foundry flexibility in moving molten metal from one furnace to another, or from one urnace ~o two or more ~eparated down-stream operations.
By mean~ of the preferred combin~tion, one may feed a single metal flow se~uentially to one of ~wo or more operatlon~.
~etal may be sequentially cast, for example, rom a molten Rupply into various downstream operations producing ~o.lid ~et~l, TH~ 2-001 ~L2 ~
forms such as lngots, sheets, foils, tubes or rods, etc,.
by use of one unit fluidic control or a ~lurality of said wnit controls in serie~, if desired.
Both soluble and insoluble zross solids includin~ fluxes, sla~, unmelted metals includinz iron, silicon, etcO, fire-brick refractory fra~ments, aluminum oxide occlu~ions, etc., which can damage the downstream volute pumps accumulate upon normal handling of molten metal in refractory urnaces and tend to collect upon and af~er formation in meltin~ and hold-in~ furnace~. As the foregoing partlculate lmpuritic~ native to handling molten zinc are inherently lighter and ~end to 10at, they tend to be drawn into top fed impeller pumps, Hence, for handlin~ molten zinc bottom fed pumps are normally selectedO On the other hand, with molten aluminum and its alloys, occluded impurities are most often heavier than the melt and tend to agglomerate and settle. Liquid aluminum metal fed into bottom-fed volute-impeller pump~ have been generally avoidedO
The prior art has su~gested multiple specialized molten metal pump a~semblies by use of alternative pump elements, including drive shats, pump impellerg as illustrative. Shorter drive shaftq have been used where top eed of molten aluminum metal to a top fed impaller pump i~ desired. If metallic zinc was to be handled, a longer drive pump shaf~ and co-relatsd inverted cup impeller fed from a bottom in~ress pump was assembled. Pump as~emblies ha~e been 80 designed as to provide bottom fed molten metal pUmp8. See Swaeney et al., U.S~ Patent 3~048/384~
One prior ar~ solution has proposed a system of rota~y baffles, referred to ag "deflector disks", driven on the same ~ THU 2-001 ~æ~L~z~
vertical drive main pump shaf~ provided controlled circum~er-ential clearance of molten metal from the meltin~ furnace by ~djustment of the dl~k clearance on the common drive shaft both above and below annulAr top and bot~om fed sinzle pump ingress means. See Sweeney et al., U.S. Patent 3,291,473.
llere, a volute pump has been described to be useful to pump molten metal inwardly through a single pump ingre~s mean~
ed from the top. However, a slngle pump impeller devoid of volute m~an~ is employed.
I~ should al80 be noted that in the top and bottom entry modifications, patentee does no~ u~e a volu~e pump and the utility does not permit ~he higher temperature~ e~sential in handlin~ mol~en me~als and i~ intended for generally lower t~mperature melting point chemicala. In either case, entry is through and pa~t rotary, driven, de1ector disks slightly upstream of ~he m~tal flow entry lnto the pump.
It is well known, however, that similar rotary power drlven disks spinning within an encloged cle~rance provlde hi~h shear dispersive forces. The high ~hear rate produced effects unwanted dispersion of forei~n matter as referred to above which contaminates the melt stream. Rotary di~per~ion action of the described classifiers tends to defea~ the filtra~ion intended and to break up and disperse in~oluble solid matter.
Here, dual volute pump~ opera~ing from a single shaft separately xeceive influx o molten metal whlch flrst is fil~ered of all su~pended ~olid~ ln the mel~ by ~n upper and lower restricted ingress zone co~pletely about the perlphery of the submers~ble pump which lnsures that the pump clearances are not unduly worn or damaged by entry of any one of the foregoing ~nmelted accumulated particul~t~s.
One prlncipal advance over the prior art herein dlsclo~ed i~ embodied in th~ moving part~ free, selective fluidics flow control means, particularly when operated in conjunct~on with the dual ingre~s dual volute pump, both of which are more fully described herein~
The liquid metal flow upon egres~ from the pump and enterin~ the downstream transition control mean~ i8 control-lably dlverted into a selected one of two diver~ent controlled downstrea~ condults or channel~ without interference wlth over-all through~put flow rate.
Commonly the principal control of molten metal flow egressing the pump has been solely through control of the pump operation. The limitation has been ~rimarily an on-off; flow or no-flow; operatlon where the driving motor means control of resultant metal flow through the pump i8 not in~tantly re~ponsiv to the "on-of" si~nals.
~ en ~n "on-off" flow con~rol 18 employed in a moving s~ream of metal, particularly, a "water hammer" develops which is detrimental to the pump function and may cause breakage of the graphite part~ required in the pump manuf~cture, This invention makes possible downstream selection of alterna~ive meltln~ and holding fu~laces and re~circula~ion within and between such furnaces and alternative delivery of a single 3tream of molten metal ~9 one of ~wo pre-selected downstream operations.
The fluidic~ devices of this lnvent~on oan be used in tandem in plural number, if deslred~ makin~ continuou~ oper2-tion from a single melting furnace, or a plurality of mel~ing or holding furnaces feeding a ~eries of varying downstream operations el~ctively and sequen~ially.
T~U 2-001 ~2~ %~ 1 S~ ~ RY OF THE INVENTION
The invention as herein di~clo~ed provides a fluidics operated molten metal flow control device operable downstream of a melting and/or holding furnaee under a relatiYely constant ingress head and laminar ~low rate. Under the foregoing condl-tion~, a fluidics controlled transition zone controls flow of a single upstream enterlng vo'lume of liquid molten oetal into one of two downs~ream alternative bifurcated egres~ channel~.
The dual channel~ outwardl.y diverge from one another at an acute angle forming interiorly thereof the basic position of solid conjoined trian~ular splitter element to be affixed thereon.
The acute angle of the splitter elemen~ exte~ds up~tream and ori~inates the demarcation point of internal stream flow divlsion~ The division apex line defines the ori~in of the outwardly diverglng channel~ downstream of ~he splitter and physically extends operably u~stream into said transition zone volume.
Upon pas~a~e of a single molten metal stream into the upper in~ress or opening lnto sai~ transltion zone, the single stream is diverged into a selected one of the ~wo divergent downstream outlet channels bu~ directed in a single ~tream through a common and expanded volume sometimes referred to herein as the tranBition zone and one slde of the spl itter in a pre-selected downstream channel, The fluidics control zone tran~itiQn piec~ integrally join~ the ~ingle up~tream en~ry channel through a transition zone of expandin~ vol~me, split by the leading acute an~le ~d&e o ~ splitter elsm~n~ partially intruding up~tream lnto _5_ , . . .
. .
~,, the aforesaid ~ransi~ion zone but downstream to e~tablish the inner walls of the two divergin~ bifurcated channels. The downstream outwardly bifurcatin~ ~in~le channels of the transi-tion æone are herein referred to for convenience as conduits or channel~ A and B. Corresponding stream~ flowing through said channels are corre~pondin~ly referred tO a~ stream A
and s~ream B.
Only one selected stream (A or B) flow~ through a corre-sponding downs~ream channel (A or B) und~r a Eiven flow control at any one time.
The specifle design of the fluidic~ control transition zone and its co-operative elem~nt~ can be specifically modifled to meet required ends for specific operations and demand condi-tlons.
One modification of the ~ransition control ~one permit~
a Eail #afe operation 80 that flow of stream B through conduit or leg B, for example, establishes that stream B will dominate (unle6s manually over-ridden).
To operate thereafter through conduit A, the remote control device must be set or fixed in operatin~ position to re establi~h and maintaln an elected flow pattern through non dominant leg k. Stream opera~ion through condult B will be resumed automatically upon relea~e of the control o~herwise directing ~he mol~en stream ~hrough channel A~ ~See Figure 7.) In another, pos~ibly preferred, metastable ~ode of opera-tlon the ~ransi~lon zone i8 as 8hown in Figure 6. Here, both eonduit A and ~ream A, or conduit B and stream B only require appropriate in~ection of a puff of compressed g~8 from the remote control ~o effect input of a controlled jet of eon~rol ..
stream gas into the appropriate control orifice and into and upstream of the transi~ion zone to imping2 upon the po"er stream to convert the stream flow from channel A to channel ~, or vice versa.
Initlal de~ign of the fluidic~ controlled transi~ion zone may restrict the cro3s-sectional area of one selected channel or le~ A or B.
l~ile it is possible to devise the cross-sectional patterns of the channels immediately upstream of, wi~hin, and downstream of the transition control including ~he single immediate ingress as may be illustrated elsewhere, it is preferred ~n the best mode of practice known, tha~ the cross-section be of ~enerally slliptical form wherein the major axis i8 vertical, as 19 illustrated in Fi~ure 8.
Such sectional control assists in maintaining laminar flow and optimum practical use of the"Coanda" or "wall effect".
O~her modifications are within the knowledge o ~he fl~idics art. Other po~sible control modification~ are not precluded, however, In the preferred form of the invention the molten me~al pump is constructed upstream and integrally a part of the downstream ingre~s control channel and metal stream into ~he single entry passageway of the downstream fluidics control transit~on zone.
While the pressure head and flow control conditions essential to functional operation~ of a fluidics control and ~ransition zone means may be established in theory and prin-ciple by gravity flow from an elevated source of supply of the required molten metal, su~h means are not amenable to ~aried plant conditlon~ and opera~ions. Operations are then limited to sin~ular and unlque posi~ions and location~
within specialized building structure~. Fur~her, in gravity operation speclal efforts may be necessary to assure the fluidic~ control unit be supplied with auxiliary heat to prevent (or to re-mel~) metal freeze-ups when the ~r~vity uni~ i8 forced to be shut down unexpectedly.
While a compre~sed ~as useful in operating the transition control zone i~ usu~lly ~n inert ~as, lllus~ratively nitrogen, in somR ln~tances minor percenta~es of usefully reactive ga~es, i11ustratively chlorine and/or arg~n, etc.~ may be blended into the control gas stream as an aid ln maintaining pur~y of the molten metal.
Impact of the pressurized control ga~ stream interiorly of the transition zone below the initial ingress point and upstr2am of the splitter initiates turbulence and development of a gas bubble. The development of a "separation bubble"
initiates the e6sential destruction of the existing "Coanda"
or "wall effect" and momentary ~tream flow ins~æbility within the transition zane a However, as the de~tabiliz~d ~tream flows close to the alternate and dlver~ing wall the "wall effect" brings the molten metal ~re~m lnto the alterna~ive and diverg~ng bifurca~ed downstrgam leg. This completes a directional flow change over and into the selected, alternate, downstream ehannel or le~ as defined by the splitter apex permanently locat~d in the enlarged volumc fur~her downstream and interior of ~he expand~ng transition plece volume.
The dynamic energy content inherent in the molten metal power s~ream cour~ing downstream from the pump (or head) i~
-~L~,~..~
~he principal source of energy in the fluidic dynamics of the fluidica flow directional control unit d~scrlbed herein, A ~econdary compres~ed gas control stream originating at the remote control point provides the ancillary ener~y source essential ~o efect growth of the separation bubble and destroy the pre-e~tabli3hed w~ll effect~ The compre~3ed ~as power ~tream i8 30metime~ referred to a~ the ~econdary control gas ~tream.
So far as i8 presently know~, movemen~ ~nd transfer of mol~en me~als and control o flow ha~ been principally u~eful in lncreasing and su~taining produetion of castings~ sheet, foil, etc~, by ~speclally de~igned m~lten metal pumps prin-cipally con~tructed of ~ refractory non-metal, most often ~raphite, to withstand the elevated temperatures, erosion and ~orrosion due to movin~ contact with molten metal at temperature~ illustratively from about 1200 to 1600F at a choice of several downstre~m plant operations. . .
Only two pumping conditions were previously controlled.
The power source, compressed air or a long shaft directly driven electrlcal motor~ could be "off" or "on". Molten metal flow either "stopp~d" or being actively pumped from with~n the melting furnace down~tream thereof~
Molten pump ~ailures prgsently most oten occur during sear~ up or ~hut-down due to sudden flow rate chan~e~.
Hammer effects when a pump i8 ~urned "off" develop severe ~trains in the pump and wear through reduced clear~ce~ within the pump i8 a~celerated. Wi~h the pre~ene combination of pump and re te control means as~ociated, and preferably integral therewith, pump ~hut-off to con~rol flow i~ no long2r mandatory, ¦ THU 2-001 '~
Use of optional forced melt circulation within the mek in~/holding furnace, now made ~ractica~le~ has se~eral advan~a~es, The time nQcessary to prepare a melt may be ~hortensd. Development of metal oxide~ and other impurities wlthln the melt h~ le6~ time to be produced due to increa~ed meltin~ rate wi~h forced circulatlon of the melt over the ~olid 3urfaces. Meltin~ o~ ~olld metal scr~p i~ poasible at hi~her furnace turnover ra~e if the ~hear rate of movement of the liquid pha~ over the solid scrap ~urface~ during melting periods i8 enh~nced.
However, known material~ and means useul to ~hange direction of flow which ch~nge~ shear rate~ B~ the molten metal powers~ream i8 either throttled down~ as in stopping, or increa~e~ in ~hear, if starting up. This action occurs in prior art valves depending upon moving parts to throttle moving stream, a~ illus~rative.
Known valve~ are not adaptable to the control of high temperature lten metal stream~, permitting as illustrativ~, an alternative pumping circulation pha~e within the melt~ng furnace and a second egre~s phase where the prepared molten metal is delivered to a point of u~e apart from the melting furnace.
A~ indicated above, molten metal - air (oxygen~ contact mu~t be avoided wherever po~ible becau~e of the high oxida-~ion reaction rate (of aluminum and oxygen~ and con~equent loss of useful m~al due to the r~pid ~ormation of in~oluble contaminating heavy aluminum oxide par~icle~, aB i8 well under~tood, Thie invention prov~de~ a ~ovel mean~ of co~trol o~
the fl4w of molten metal ~hrough ~elected and alt~rnatlve channels or conduit mean8 without corrosion or wear upon the surace of moving control valve6 designed to chan~e rates of flow and thereby undergo wear. Change in flow directions into one of ~wo el~c~ed flow path~ as i~ accomplished herein without materially interruptin~ the normal flow ra~e of th~
princlpal or "power" molten metal ~tream h~s not been hereto-fore known.
In the utilization of the fluidic~ controlled transltion ; control mean~ of this invention the requiremen~s of standard-lzed pres~ure, flow ra~e and ~he laminar flow character of the stream are ~mportant to the dependable operation of the device.
In use, the pump ~ssembly a~ herein described is sub-merged in molten metal. Molten ~etal enters ~he upwardly extending central cup of the top volute pump by pa~sage through ~, an extended controlled molten metal clearafice zone or volume which provide~ effective filter m~ans. The extended filter zone is created by means of an extended ~pecial ingress volume defined by the dual top horlzontal spàced apart plates of the I pump assembly ~hrough which top llquid entry occur~ and a i like bo~tom ingres~ zone created by spacer feet between the interior flat bottom of the furnace and the bottom horizontal plate o the submerged p~mp baseO Note th~t bo~ the en~ire periphery o ~he pumpj bo~h bop and bo~om, d~fine ~ filtra-tion zone ingress means lnherent whe~ the pump i~ in uAe These clearanee entry 810~8 or filtxa~ion ~lements a~sure absence of in801ublc accretions in ~he incom~ng mel~.
Fu~ther, a~ the vol~e of ingres~ liquid entering the pump ori~inate~ over bo~h top and bottom of the pump per~phery, dL~DYtd2~;
thu~ the developed ~hearing 8tre89 i~ insufficient to disinte-grate occluded insoluble "tramp" material~ commonly contamina-ting a molten metal durlng ~elting, holdlng and transfer.
~hunk~ of refractory brlck, undi~solved 8illcon meta~,,oacluded insoluble metal oxides, e~c., cause at best e~ce~sive wear, and more often abrupt breaka~e of pump part~ which are at close tolerance~, Carry ~hrou~h of in~oluble metal oxlde aCcretionR i8 not only ob~ectionable in proce~sing m~lten m~tal~ but insoluble metallic impuritle~ in the mel~ if not removed downs~ream, are a cause or reie~tio~ of co~pletely formed metal part~ and useful product~ derived therefrom.
The. disclo~ure herein com~rises two clo~ely related inventive entities most often in advantageous functional combination, but e~ch of which can be operated separately, but always ~dvflntageously arranged in series compri~ing the improved molten metal pump and the correl~tive downstream control mean~.
The principal novel entity in the combination comprises a molten met~l fluid flow ~irective control device dependent for itB operation upon a reliable ~ource of molten metal flow.
~elatively con~ant flow rate, constant pre~sure head and freedom from occluded insoluble particulate~ And es~entially laminar flow are derivat~ves essential and dependent upon a qu~lity molten metal p~mp upstream of the said control.
The flow control device of this inventive combination is charac~erlzed by a ~in~le fluid ingress channel, dually diver-gent blfurcated egres~ channela down3tream and intermedlately of ~aid single ingress andl the b~ furcated egras~ ch~nnels a ~¦ THU 2-001 ~L2~i~%~
fluldlcs ~ontrolled transition zone, 3 stream directing exit orifice t~rminating said sln~le ingreas mean~ down~tream of : sa~d e~r~s and entering said transition zone, oppositely dispoaed inwardly directed pressurized ~as control ports adap~ed to control dlfferential ~as pres~ure3 interiorly of said egress zone At said exit oriice, said transltion zone expandin~ ln volume downstream to ~ccommodate ~ sln~le enlarged entry zone in~o ~aid dual bifurc~ted downstream egress channels which channels separate and diverge at an acute angle 7 interl-orly thereof iB et a conjoi~ed ~olld triangular splitter element the apex of which ex~end~ upstream i~to the downstream terminus of ~aid expanded transitlon zone volume; said diagonally opposed ~as pressure control ports upstream in the transition provide control from a remote poin~ of origin of said essential pressure controlling gas ports~
The pump so~rce specifically referred to above of a m~lten metal flow having relatively co~stant lamin~r flow rate, pressure head and freedom from "tramp" particulate solids is preferably operated in inte~ral combination wi~h the fore-goin~ fluidlcs molten metal flow control device. The~e separately and dual function~, but preferably physically unitary elem~nts, comprise in combin~tion a uni~axy molten metal pump with selective directional output control means downstream thereo~, The comb~nation assembly provides inter-relating and inter-related lmprovement in the handling of refractory molten m~tal by f~nctional immers~on in mel~ng/
holding furnaces.
,, /
I ~
BRIE~ DESCRIPTION O~ THE DRAWINGS
Fi~ure 1 is an elevatisn partially in sectlon not2d with parts broken away of a molt~n metal pump in operative ~ association with a ~olten metal bath or mel~ing furnace~
: Figure 2 is a psrtial se~tional view along the line
2 2 of figure 1.
Figure 3 ia ~ top v~ew of th~ unit pu~p assembly indicatin~ co-relation of the pump ass~bly with a preferred form of a s01ective fluidics control zon~.
Figure 4 is an enlarged partial elevation in section detailing essentials of the molten ~etal pump and a fluidics . control zone.
;~ Figure 5 is a top ~ectional view fllong the line 5-5 of Figure 1.
Figure 6 is a sectional view along the line 6-6 of Figure 1 de~ailing operational elements of the fluidics control device and volute pump.
Figure 7 is detailed develop~ent o~ an al~ernatiYe arrange~ent of another specific modification of the fluidics control zone.
,~
Figure 8 is a sec~ional view as seen upstrea~ of the broken line 89 of figure 6 and 7.
DETAIL~D D~SCRIPTION OF THE PREFERRED E~BODIMENT
This invention i8 dlrec~ed to a fluidics flow control device ~o make posf,ible dlvisi~n of a sin~le ~lten metal egre~s ~tream into a pre-selected one of two pofg~lble e~re~s condults. In the broadest aspect, the flow control device can be detachably affixed downstream of a relatlvely constant source of mol~en metal flow h~vin~ the required pre~sure head and flow rate ~o provide reliable operation throu~h a down stream flu~dics operated dlrectional control meanFg providing for selectioslal direction of the metal ~ream through one of two avallable channels.
A plurality of the fluldlcs control devices may also be set up in series or in a eontinuous downstream sequence to provide a plurality of controllably directed me~al streams from but one original single m~lten met~l stream.
A controlled source o molten metal havin~ requisite pre~sure he~d and controlled flow ra~e i~ pre~er~bly obtalnad from use of a molten metal pump ~ubmersed in a molten metal meltin~ and/or holdin~ furnQce, It i8 al80 conceived of originating in select foundries where the meltin~/holding furnace~ are a floor or more above ~he casting or metal forming operations~ Thi~ mean~g depend~ng upon gravity flow, may ~upplan~ the otherwise essential liquid metal pump.
A ~r~vity 8y~tel3 will perm:it operation of the fluidics control device of this invention when the output rate i8 held relatively con~tant. Gravity a~tachm~nt i~ no~ oten adaptable to general plant operation a~ a separate flow control ~ t. 'The use of a ~ood quali~y prior art ~olten metal pl~mp i~ also potentiall r :.
I
useful in ~equential combination of one, or a plurality of more than one fluidic~ flow control devices ~8 herein disclo~Pd.
The preferred embodiment of the fluidi 8 con~rol æone of thl~ invention 1B lntegrally ~ part of and supported within a molten metal pump assambly. The combination bccomes a ~nitary piece of processing e~ulpment. In use; it 1~
functio~lly ~ubmerged in a molten meltin~/holding furnace.
The unitary assemblies h reln are portably movable upon demand from one metal/holding furnace by mean~ of power lift-in~ unl~. Advantageous plant operation fl~xiblllty i8 thereby ~llowed.
The preferred embodiment of ~he fluidics control unit of this invention i~ shown and d~cribed as a u~ieary par^c of an inventive metal pump, al80 described here, particularly accommodated to the tran~fer of both molten aluminum and ~olten zlnc.
Heretofore, beeause of the es~enti~l lnherent differences in phy~ical and chemical behavior of ~hese m~tals in molten state, either two separately desi~ned pumps, or one pump having electlve parts, assembled for ~he ~pecific elected metal ha~
been dlsclo~ed in ~he prior ar~.
This wri~ing disclo~es a pump integrally as~embled ~o opera~e in con~unction with a fluidics control device. The herein disclosed improved me~al pump ean be used without modification and provides molten metal ~low characterl~tics particularly deAirRble in direct down~tream operatlon of the ~aid fluidios control unlt fir~t above lntroduced.
Referring more particularly to the drawlngs:
A metal meltingtholding furnace 5 in Figure 1 holds portable molten metal pu~p as~embly 10 partlally i~mer~ed l THU 2-001 i ,~
ln~o ~nd elevated into positlon by power llft means ~hrou~h hanger 1~ of mounting ~s~embly plat~ 3 of top ~tor mounting a~sembly 15. Air dr~ven motor 2 ~uppor~ed by a ~op motor untin~ as~embly pl~te lS drive~ pump 30 throu~h power sha~t 7 and through univer~al join~ 6 and b~yonet coupling 4. A
p~ir of c~ntrally drilled vertic~l po~t~ 9a and 9b, and a pair of centrally drilled hollow riser~ 20a and 20b pa88 throu~h horizontal ~uppor~ plate 3 ~erminatin~ ln elbows l9a and ~Oa above the support and riser ~ockets 21a and 21b, ~upportably connect below and adhefiively ~et within subm~r~ed rec~ilinear pump base 30~ Posts 9a and 9b, centrally drilled rlsers 20a ~nd 20b and all other parts below the po~ ~nd riser ~ockets 6ub;ected to be ~ubmersed into molten metal furnace box 5 are fabricated of refractory sub~tances, graphite being generally u6ed. Silicon carbide i8 often used where wear 1B greate~t.
All pa~t~ are m~chined to clo~e tolerances; and a~embly, where not otherwise ~hown, i8 obt~ined through u~e of high temperature adhes~ves.
Driven shaft 7 is rotatably supportPd in top plate 16 of box 30 and extend~ centrally downward through bore 60 to a threaded shaft of bottom end 7c. Bearing moun~ 17 and mounting ring 18 ar~ fitted i~ a top vertical bore throug~ ~late 16 and support ~haf~ 7b rotatably within said a~sembly~ Lower shaft end 7c threadably engages bo~h upper ~olute impeller 46 and lower volute lmpeller 45 of dual volute pUmpS m~unted back to back. Both 45 and 46 impeller~ are ~imNlt~neously driven in a clockwl~e directlon (as i~di~a~ed in Figure 6~. Axlally centered disk-llke impeller elem~s 83a of impeller 46 extends upwardly and ~utwardly an~ 83b ex~ends outwardly and do~nwardly .
from i~pell~r 45 within bore 60. ~ach of the~e disk-like lmpeller element~ 83 create an axial uppPr and lower ~ntry volume 82a and 82b (Fi~ure 6 - Fi~ure 7).accommod~t~d to receive molten metal f rom interior of furnace 5 throu~h ~ep~r-ats entry m~an~ a~ fOllOWB:
Upon clockwi~ rotation of shaft 7 through actlvation of motor 2 volute impellers 45 and 46 are rotated withln their re~pective ~tationa~y volutes 47a and 47b. Molten me~al flows from the submerged molten metal environment of furnace 5 through restricted top en~ry volume 37 created between top plate 16 and top plate of box 3~ ex~endlng co~pletely about the pum~ base periphery ~nd into the interlor of the axial volume of elemen~ 83a of top volute impeller 46~ Separately, molten m~tal flows downardly about the exterior perlphery of box 30 ~hrou~h restrlcted pa~sageway 36 into bottom bore 60.
Spacer studs or le~s 35 m~unted on the planar bottom of box 30 define a separAte and reetrict~d entry passageway interiorly of dl3k-llke axlal volume 83b of lower volute 45.
Each of the above restric~ed ~nd separated entry pa~sageways 36 and 37 act to filter out su~pended sollds whlch m~y be unmelted chunks of metal scrap, silieon metal incorporated a~
an alloying element in the mRl~ which w~ll ultim~tely dis~olve, contamlnan~s which include lnsoluble foreign msterial includ-ing refra tory brick spalled frum furnace wall~, chunks of ~ement, ln~olubl~ metal oxlde accr~tions, etc., mu~h of the above, particularly insoluble ~Itramp~ occulslon~ when pr~sent eontrlhute 'co exce~ive wear and tear and often breakage of pump element~ lncluding volutes and lmpellers.
THU 2-OOl '~
~ lth driven ~haft 7 acti~ely driven throu~h motor 2, centrifugal force~ actin~ upon each of the molten me~al ~treams from ~he furnace interiors flowin~ lnteriorly into the axial cavitie~ 83a and 83b force the molten metal therein outwardly and rearwardly (to the dlrection of rota~ion) through plural impeller passageway~ 79 under the ~o increa~ed centrl-fugal pre~surea developed. Dual 1uid molten metal stream~
are expelled from their respective volute pump~ in the volumRs be~ween the stationary volute piece~ 47a and 47b and volu~e impeller~ 45 and 46 into a single ef~lux straam downstream of the pump through lten metal pump exlt orifice 80.
In the preferr~d orm of the invention a~ here more specifically of concern, the ~ingle exit strenm of molten metal from the exit oriflce 80 is pumped through common exlt channel 8S ~Figure~ fi and 7) which i8 ~180 the common ingress point o~ ~he mol~en metal stream into the ups~ream end of fluidics controlled transition zone 5~ at 87.
At this point the m~lten metal enters the transition zone under sub~tantially a constant pres~ure and flow rate of the li~uified metal.
If one eleot~, the fluidics operated transition control meanR 50 can be totally replaced with an uninterrupted conduit section (not ~hown3 from the upstre~m entry at 87 thereln through ~ single down~ream channel ~functloning as a cho~en one of two bifurcated downs~ream le~ or channels A or B).
The ~oregoing change ellmlnates ~he added u~ility and adaptability o ~he fluidic~ control zone SQ and the choi~e of di~tribution of any one of two downstream liquid molten metal outputs at a ~iven time wi~houe fully utilizlng the T~U 2~001 inheren~ lmprovements prPviously di3closed in expo~ltion of the :lmpro~ed molten metal pump a~sembly.
l~owever, the preferred form of the invention ~brace~
both the advances in versatility and capacitle~ of the metal flow as are inherent in the above de~cribed molten ~etal pump unit havin~ a~ integrally ~ part thereof the fluldic~ capacity to effec~ a change in directlon of the pump outlet ~trea~
wi~hout movable m~chanlcal parts.
Returning to the dr~win~, Fi~ure 6 and Figure 7 pick up the down~tream flow of lt~n m~tal as it egre~ses under required flow conditlon~ from the upatream pu~p and e~resses downstream therefrom into the fluidics control transition zone 50 of the down~tream flow direction fluldic~ selector device.
The fluidica control zone for referral $8 so~etimes herein referred to and descriptively ident~f~ed as a control zone transitlon piece 50 althou~h the entire control unit iB
preferably integral with the improved pump.
Satisfactory~opcration of the fluidics control zone as a unit embrace~ not only the lmn~diate transition zone 50 bu~ also generally including the flow control æone se~ out by dot~ed line~ 87 and 89; and further includes con~lderatlon o the immediate ingres~ zone 85 ~nd the two le~ A and ~ of the alternative flow streams A and B downstream~
In the pre~rred form o the inY~ntion, ~he cros~ sectlon of the connectin~ condult betwe~n th~ liquid metal leavlng the pump a~ 80, the crofls sectional pa~te~n ~hrough ~ny ~ec~ion of the exp~nding volume transit~on zone 85 and the ~wo leg3 A and B are of importanee to obtain ~he op~imum influence of 2 ~
fluldics forces. The "Coanda" or "w811 ~ffect'l depends upon relativ~ constancy of pres~ure he~, pressurc upon the moltPn ~tream flowln~ w~thin the enclosed wall~ and a ~ubstantlally lamellar or axi~l flow of th~ m~tal through the control unit except under activation of ~ flow ch~n~e direction by impin~e-ment on and into the downstream power stream of molten metalby means of a controlled pressurized ga~ ~ream.
It ~8 preferable in the cons~ructlon o~ the 1uldics control for the purpsse~ herein ~hat ~he imned~ate pump egress 8S, the control zone S0 and the two bifurcated downstream l~gs be con~ru ~ed from ~raphite tubes h~vin~ an elliptical section wherein the ma~or axl9 thereof i8 vertical. Rddy current~
withln this c~itical zone are not encouraged, m~ximNm side "wall effect" i8 obtained over the lareest ma88 of 10wing metal with m~nimum wall ~rea reactive response at the top a~d bottom of ~he aoresaid pa~sageway~. Due re~ard for ~he ratio of the ma~or axis to the minor axis o~ ~he elliptlcal section w~ll take into cons~deration the molten metal pum~
output rate which iB to pas~ throu~h the 1uidics zone 50 per unis of time. Figure 8 illustrate~ a general elliptic~1 ~ection as preferred in the above eritical flow control zone con~truction, It is withi~ thi~ zo~e that certain fluidic principle3 are m~de effective rom a remot~ control polnt (no~ ~hown), The reD~te control point house~ and includes means of control-ling and e~tabli~hing a varie~y of gas pre~sure~ which may be above a~mospheric, at atmo~pherlc, or merely vented ~o normal atm~spheric pr~s~ure~, or co~blna~ions of both by gas pasæageways ~uch as are illus~rated in ~i~ure 6 and ~ nter~
ing into the transition zone at 95 and 96 and ~peciflcally T~,W 2-001 a~ vents under inert ga~ pres~urss both above and at a~mos-pher$c pressure and gen~rally de~igned to ven~ tD the ~tmos-phere when present as ~hown at 109 and 110 in Flgure 7.
Available ~t the remote control point leRding ~o transl-tion zone 50 are indivldual ~a~ line~ connecting with in~eriorn of the transition zone at the indlca~ed pre determined loca~ion~
in ga~ ingress and e~ress oriflces, The upstream palr o orificeQ en~ring the control zone 50 at 90 and 91 origina~lnz throu~h iner~ ga3 line~ 95a an~ 96a are u8ed in alternatin~
function. If gas presure above ~tm~pheric i8 applied to one /
orifice 90 from it~ remote control ~ource, the other orifice 91 ~enerally i8 held at or near ~tandard a~mospheric pressures.
~ lowever, in Figure 7 gas lines 109 and 110 are normally merely vents through ga~ control pipellne~ from control ~one 50 exhaus~ng at atmospheric pre~sures, but controlling pressure~ at the ob~erved gas ingr~ss positions P and Q down-~t~aam o~ th~ ~ran~l~ion æon~.
Referring to Figure 6, a point of beginning presumes the fluidlcs condition~ in the generally expanding volume down-stream in tr~nsitlon zone S0 are uch that the molten metal power ~tream flows into the zone at 87, past control ports 90 and 91, and is held by the "Coanda wall effect'~ in con~act with wall 100 of channel o~ le~ A of the bifurcat~d egress zone ~erminating transition zone 50 a~ 89. ~ere the m~l~en stream p~8e8 leadln~ edge 103 ~or 102~ of the solid splitter 82 and co~tlnues downstream through channel A to be discharged throu~h r~er 20b ko a pre-determlned o~min~ opera~lon, a secondary holding furnace, or perhap~ to be r~-circulated wi~hin the meltln~ furnace 5.
~ %~
~ en required for use in a seoond Bet of do~nstream production re~uiremen~s or holdin~ conditions, the operator can re-dlxec~ ~he molten metal ~tream enterin~ the transl~lon zonP at 87 ~o the altern~te leg or ch~nn~l B by directing, from the remo~e control location, eha~ a puff of substantially inert ga~ under pr~ure be di~charg~d through gas line 95a ~nd oriflce 90 into control zone 50. Orifice 90 18 po~i~ioned ~ligh~ly downstream of llne 87 in wall lOOo A~ the pressllrized ga~ stream puff impact~ the down~tre~m metal power stream at orifice 90, a turbulent condition re8ult8 in the power stream and a ~eparation bub~le develops. The developed turbulence creates an in~tabllity in the power liquid metal ~tream along the wall 100 causing it to veer towards ch~nnel or leg B. As the power stream contact~ wall 105 of l~g B, the "Coanda or wall effect" take~ over, ~he power stre~m becomes re-attached to wall ld5.
The power metal ~tream continues to 10w in channel B
completely changed in course from channel A a8 it flows pa8t divisional apex 103 of the splitter 82. The now re-dlrected flow of the m~lten met~l continues to flow down~tream ln and through eha~nel B and out riser 20a to a second, And alternative pre-determined mode of functlo~al use of the diver~ed molten metal power str~am.
A8 illustrated in Figure 6, a bi-~table fluidics 8y8t2m i6 designed into the transition zone 50. To re~urn the down-~tream m~tal flow to channel A and riser 20b, a counter puff of compres~ed gas directed through upper support pla~e 3 (Figure 1~, ver~ical drill~ed poas~ 9a and gas line ~it~in~
9ba fro~ the r~ te contxol posltio~ ~nd a compres~ad ga~ 3upply source lnto di~ruptive contact with the power 8tr2~m through ...
2 ~i ~ THU 2-001 ~ 2 ~
oriflce 91 to a8ain rever~e and re~e~tabllsh the original 10w through channel A. The ~ontrol puf of gas ~nters into a ~eparation bubble existant and ad~acent the establi~he~
power metal downstream le~ or ch~nnel (here B~ to çffect the elected power s~ream flow dlrectional h~n~e.
A~ ~he combin~tion of pump ~nd down~tream control mean~
operate: with molten meeals 9 a fail ~afe device mRy be deslreable and u~ed to advanta~e in peclf~c applicatlons.
Figure 7 illustra~es a m~diicatlon of Flgure 6 wherein a more complex modlfication of ~he tran~lt~on zon~ 50 1~ shown.
A mono stable 10w pa~h dominates ~nd prevaila ~hould there be a failure in the inert ga~ control ~upply essential to the dominatioII of a given leg, stream or channel A or B.
Referr~ng to Figures 7, it will be noted that inlet power gas control ports 95a and 96a have been displaced upstream towards the dual volute pu~p as~embly. The effect i8 tO alter slightly the angle of attack of control port~ 90 and 91. ~ote also exit orifice 85 enterR tran~ition zone 50 at. 87 at an offset angle more favorable to ingres~ of the power moltPn me~al stream flow from the pump at pump volute egreas 80 into the transi~ion control zone 50 at 87.
An arcuate CU8p 102 has been eut into and rem~ving the for~er sharp leading edge 103 of splitker 82 entering the transition zone 50. Gu~p 102 extend~ upstream into trangition æone 50 to cause an increa e in lnternal pre~sure on the hlgh pressure side of molten m~tal pow~r stream as it flow6 through expandin~ volume transltion zone 50. Increased lnta,rnal pre~sure lncrease~ the st~bil~ty of .he liquid metal flow direction under po~3ible minor flow variation ~n ies rate and/or pre~sure, for example.
-2~-.~1 '~
Vents 109 and 110 which have been added downstream in the trsnsition zone (near the zone exlt llne At 89) lead through a~soclated ~as conduit mean~ interiorly of control zone 50 and provide mean~ to control ga~ pressures as re~uired at point~ of entry P and ~ in~o downstream leg~ A and B. with-in down~tream limit~ of transition zone 50 at 89.
Note that liquid m~t~l power in~res~ into ~ransition zone 50 at 87 i~ ~lightly asymD~trical or at a slightly of~et an~le. The resultant fluidic ~orces favor fluid flow through channel B, which Eorces will domina~e and mal~tain the control unless a pneuma~ic gas control 81gn~1 through control port 91 i8 con~tantly m~intained.
Thuff, the ba~ic mono~table 10w pattern of the power streEm can be employed should one ~l~ct to proce~s a molten met~l ~tre~m through channel,~ for principal end use~ where no molten me~l over10w problem~ from the egress of riscr 20b occur. For example, flow fro~ ri~r 20b m~y normally re-circulate liquid metal back through the meltin~ or holdin~
furnace 5 to increase the mel~in~ rfite of scr~p metal solids being remelted. For a specific term, however, the pneumatic gas control por~ 91 rould be activated for other specific operations while bPing care~ully ob~erved. Shoult the opera~or's a~ention be dlverted, ~he ~hift back would au~o-n~tical eturn the hot met~l ~treem to ch~nnel B.
Figure 3 ia ~ top v~ew of th~ unit pu~p assembly indicatin~ co-relation of the pump ass~bly with a preferred form of a s01ective fluidics control zon~.
Figure 4 is an enlarged partial elevation in section detailing essentials of the molten ~etal pump and a fluidics . control zone.
;~ Figure 5 is a top ~ectional view fllong the line 5-5 of Figure 1.
Figure 6 is a sectional view along the line 6-6 of Figure 1 de~ailing operational elements of the fluidics control device and volute pump.
Figure 7 is detailed develop~ent o~ an al~ernatiYe arrange~ent of another specific modification of the fluidics control zone.
,~
Figure 8 is a sec~ional view as seen upstrea~ of the broken line 89 of figure 6 and 7.
DETAIL~D D~SCRIPTION OF THE PREFERRED E~BODIMENT
This invention i8 dlrec~ed to a fluidics flow control device ~o make posf,ible dlvisi~n of a sin~le ~lten metal egre~s ~tream into a pre-selected one of two pofg~lble e~re~s condults. In the broadest aspect, the flow control device can be detachably affixed downstream of a relatlvely constant source of mol~en metal flow h~vin~ the required pre~sure head and flow rate ~o provide reliable operation throu~h a down stream flu~dics operated dlrectional control meanFg providing for selectioslal direction of the metal ~ream through one of two avallable channels.
A plurality of the fluldlcs control devices may also be set up in series or in a eontinuous downstream sequence to provide a plurality of controllably directed me~al streams from but one original single m~lten met~l stream.
A controlled source o molten metal havin~ requisite pre~sure he~d and controlled flow ra~e i~ pre~er~bly obtalnad from use of a molten metal pump ~ubmersed in a molten metal meltin~ and/or holdin~ furnQce, It i8 al80 conceived of originating in select foundries where the meltin~/holding furnace~ are a floor or more above ~he casting or metal forming operations~ Thi~ mean~g depend~ng upon gravity flow, may ~upplan~ the otherwise essential liquid metal pump.
A ~r~vity 8y~tel3 will perm:it operation of the fluidics control device of this invention when the output rate i8 held relatively con~tant. Gravity a~tachm~nt i~ no~ oten adaptable to general plant operation a~ a separate flow control ~ t. 'The use of a ~ood quali~y prior art ~olten metal pl~mp i~ also potentiall r :.
I
useful in ~equential combination of one, or a plurality of more than one fluidic~ flow control devices ~8 herein disclo~Pd.
The preferred embodiment of the fluidi 8 con~rol æone of thl~ invention 1B lntegrally ~ part of and supported within a molten metal pump assambly. The combination bccomes a ~nitary piece of processing e~ulpment. In use; it 1~
functio~lly ~ubmerged in a molten meltin~/holding furnace.
The unitary assemblies h reln are portably movable upon demand from one metal/holding furnace by mean~ of power lift-in~ unl~. Advantageous plant operation fl~xiblllty i8 thereby ~llowed.
The preferred embodiment of ~he fluidics control unit of this invention i~ shown and d~cribed as a u~ieary par^c of an inventive metal pump, al80 described here, particularly accommodated to the tran~fer of both molten aluminum and ~olten zlnc.
Heretofore, beeause of the es~enti~l lnherent differences in phy~ical and chemical behavior of ~hese m~tals in molten state, either two separately desi~ned pumps, or one pump having electlve parts, assembled for ~he ~pecific elected metal ha~
been dlsclo~ed in ~he prior ar~.
This wri~ing disclo~es a pump integrally as~embled ~o opera~e in con~unction with a fluidics control device. The herein disclosed improved me~al pump ean be used without modification and provides molten metal ~low characterl~tics particularly deAirRble in direct down~tream operatlon of the ~aid fluidios control unlt fir~t above lntroduced.
Referring more particularly to the drawlngs:
A metal meltingtholding furnace 5 in Figure 1 holds portable molten metal pu~p as~embly 10 partlally i~mer~ed l THU 2-001 i ,~
ln~o ~nd elevated into positlon by power llft means ~hrou~h hanger 1~ of mounting ~s~embly plat~ 3 of top ~tor mounting a~sembly 15. Air dr~ven motor 2 ~uppor~ed by a ~op motor untin~ as~embly pl~te lS drive~ pump 30 throu~h power sha~t 7 and through univer~al join~ 6 and b~yonet coupling 4. A
p~ir of c~ntrally drilled vertic~l po~t~ 9a and 9b, and a pair of centrally drilled hollow riser~ 20a and 20b pa88 throu~h horizontal ~uppor~ plate 3 ~erminatin~ ln elbows l9a and ~Oa above the support and riser ~ockets 21a and 21b, ~upportably connect below and adhefiively ~et within subm~r~ed rec~ilinear pump base 30~ Posts 9a and 9b, centrally drilled rlsers 20a ~nd 20b and all other parts below the po~ ~nd riser ~ockets 6ub;ected to be ~ubmersed into molten metal furnace box 5 are fabricated of refractory sub~tances, graphite being generally u6ed. Silicon carbide i8 often used where wear 1B greate~t.
All pa~t~ are m~chined to clo~e tolerances; and a~embly, where not otherwise ~hown, i8 obt~ined through u~e of high temperature adhes~ves.
Driven shaft 7 is rotatably supportPd in top plate 16 of box 30 and extend~ centrally downward through bore 60 to a threaded shaft of bottom end 7c. Bearing moun~ 17 and mounting ring 18 ar~ fitted i~ a top vertical bore throug~ ~late 16 and support ~haf~ 7b rotatably within said a~sembly~ Lower shaft end 7c threadably engages bo~h upper ~olute impeller 46 and lower volute lmpeller 45 of dual volute pUmpS m~unted back to back. Both 45 and 46 impeller~ are ~imNlt~neously driven in a clockwl~e directlon (as i~di~a~ed in Figure 6~. Axlally centered disk-llke impeller elem~s 83a of impeller 46 extends upwardly and ~utwardly an~ 83b ex~ends outwardly and do~nwardly .
from i~pell~r 45 within bore 60. ~ach of the~e disk-like lmpeller element~ 83 create an axial uppPr and lower ~ntry volume 82a and 82b (Fi~ure 6 - Fi~ure 7).accommod~t~d to receive molten metal f rom interior of furnace 5 throu~h ~ep~r-ats entry m~an~ a~ fOllOWB:
Upon clockwi~ rotation of shaft 7 through actlvation of motor 2 volute impellers 45 and 46 are rotated withln their re~pective ~tationa~y volutes 47a and 47b. Molten me~al flows from the submerged molten metal environment of furnace 5 through restricted top en~ry volume 37 created between top plate 16 and top plate of box 3~ ex~endlng co~pletely about the pum~ base periphery ~nd into the interlor of the axial volume of elemen~ 83a of top volute impeller 46~ Separately, molten m~tal flows downardly about the exterior perlphery of box 30 ~hrou~h restrlcted pa~sageway 36 into bottom bore 60.
Spacer studs or le~s 35 m~unted on the planar bottom of box 30 define a separAte and reetrict~d entry passageway interiorly of dl3k-llke axlal volume 83b of lower volute 45.
Each of the above restric~ed ~nd separated entry pa~sageways 36 and 37 act to filter out su~pended sollds whlch m~y be unmelted chunks of metal scrap, silieon metal incorporated a~
an alloying element in the mRl~ which w~ll ultim~tely dis~olve, contamlnan~s which include lnsoluble foreign msterial includ-ing refra tory brick spalled frum furnace wall~, chunks of ~ement, ln~olubl~ metal oxlde accr~tions, etc., mu~h of the above, particularly insoluble ~Itramp~ occulslon~ when pr~sent eontrlhute 'co exce~ive wear and tear and often breakage of pump element~ lncluding volutes and lmpellers.
THU 2-OOl '~
~ lth driven ~haft 7 acti~ely driven throu~h motor 2, centrifugal force~ actin~ upon each of the molten me~al ~treams from ~he furnace interiors flowin~ lnteriorly into the axial cavitie~ 83a and 83b force the molten metal therein outwardly and rearwardly (to the dlrection of rota~ion) through plural impeller passageway~ 79 under the ~o increa~ed centrl-fugal pre~surea developed. Dual 1uid molten metal stream~
are expelled from their respective volute pump~ in the volumRs be~ween the stationary volute piece~ 47a and 47b and volu~e impeller~ 45 and 46 into a single ef~lux straam downstream of the pump through lten metal pump exlt orifice 80.
In the preferr~d orm of the invention a~ here more specifically of concern, the ~ingle exit strenm of molten metal from the exit oriflce 80 is pumped through common exlt channel 8S ~Figure~ fi and 7) which i8 ~180 the common ingress point o~ ~he mol~en metal stream into the ups~ream end of fluidics controlled transition zone 5~ at 87.
At this point the m~lten metal enters the transition zone under sub~tantially a constant pres~ure and flow rate of the li~uified metal.
If one eleot~, the fluidics operated transition control meanR 50 can be totally replaced with an uninterrupted conduit section (not ~hown3 from the upstre~m entry at 87 thereln through ~ single down~ream channel ~functloning as a cho~en one of two bifurcated downs~ream le~ or channels A or B).
The ~oregoing change ellmlnates ~he added u~ility and adaptability o ~he fluidic~ control zone SQ and the choi~e of di~tribution of any one of two downstream liquid molten metal outputs at a ~iven time wi~houe fully utilizlng the T~U 2~001 inheren~ lmprovements prPviously di3closed in expo~ltion of the :lmpro~ed molten metal pump a~sembly.
l~owever, the preferred form of the invention ~brace~
both the advances in versatility and capacitle~ of the metal flow as are inherent in the above de~cribed molten ~etal pump unit havin~ a~ integrally ~ part thereof the fluldic~ capacity to effec~ a change in directlon of the pump outlet ~trea~
wi~hout movable m~chanlcal parts.
Returning to the dr~win~, Fi~ure 6 and Figure 7 pick up the down~tream flow of lt~n m~tal as it egre~ses under required flow conditlon~ from the upatream pu~p and e~resses downstream therefrom into the fluidics control transition zone 50 of the down~tream flow direction fluldic~ selector device.
The fluidica control zone for referral $8 so~etimes herein referred to and descriptively ident~f~ed as a control zone transitlon piece 50 althou~h the entire control unit iB
preferably integral with the improved pump.
Satisfactory~opcration of the fluidics control zone as a unit embrace~ not only the lmn~diate transition zone 50 bu~ also generally including the flow control æone se~ out by dot~ed line~ 87 and 89; and further includes con~lderatlon o the immediate ingres~ zone 85 ~nd the two le~ A and ~ of the alternative flow streams A and B downstream~
In the pre~rred form o the inY~ntion, ~he cros~ sectlon of the connectin~ condult betwe~n th~ liquid metal leavlng the pump a~ 80, the crofls sectional pa~te~n ~hrough ~ny ~ec~ion of the exp~nding volume transit~on zone 85 and the ~wo leg3 A and B are of importanee to obtain ~he op~imum influence of 2 ~
fluldics forces. The "Coanda" or "w811 ~ffect'l depends upon relativ~ constancy of pres~ure he~, pressurc upon the moltPn ~tream flowln~ w~thin the enclosed wall~ and a ~ubstantlally lamellar or axi~l flow of th~ m~tal through the control unit except under activation of ~ flow ch~n~e direction by impin~e-ment on and into the downstream power stream of molten metalby means of a controlled pressurized ga~ ~ream.
It ~8 preferable in the cons~ructlon o~ the 1uldics control for the purpsse~ herein ~hat ~he imned~ate pump egress 8S, the control zone S0 and the two bifurcated downstream l~gs be con~ru ~ed from ~raphite tubes h~vin~ an elliptical section wherein the ma~or axl9 thereof i8 vertical. Rddy current~
withln this c~itical zone are not encouraged, m~ximNm side "wall effect" i8 obtained over the lareest ma88 of 10wing metal with m~nimum wall ~rea reactive response at the top a~d bottom of ~he aoresaid pa~sageway~. Due re~ard for ~he ratio of the ma~or axis to the minor axis o~ ~he elliptlcal section w~ll take into cons~deration the molten metal pum~
output rate which iB to pas~ throu~h the 1uidics zone 50 per unis of time. Figure 8 illustrate~ a general elliptic~1 ~ection as preferred in the above eritical flow control zone con~truction, It is withi~ thi~ zo~e that certain fluidic principle3 are m~de effective rom a remot~ control polnt (no~ ~hown), The reD~te control point house~ and includes means of control-ling and e~tabli~hing a varie~y of gas pre~sure~ which may be above a~mospheric, at atmo~pherlc, or merely vented ~o normal atm~spheric pr~s~ure~, or co~blna~ions of both by gas pasæageways ~uch as are illus~rated in ~i~ure 6 and ~ nter~
ing into the transition zone at 95 and 96 and ~peciflcally T~,W 2-001 a~ vents under inert ga~ pres~urss both above and at a~mos-pher$c pressure and gen~rally de~igned to ven~ tD the ~tmos-phere when present as ~hown at 109 and 110 in Flgure 7.
Available ~t the remote control point leRding ~o transl-tion zone 50 are indivldual ~a~ line~ connecting with in~eriorn of the transition zone at the indlca~ed pre determined loca~ion~
in ga~ ingress and e~ress oriflces, The upstream palr o orificeQ en~ring the control zone 50 at 90 and 91 origina~lnz throu~h iner~ ga3 line~ 95a an~ 96a are u8ed in alternatin~
function. If gas presure above ~tm~pheric i8 applied to one /
orifice 90 from it~ remote control ~ource, the other orifice 91 ~enerally i8 held at or near ~tandard a~mospheric pressures.
~ lowever, in Figure 7 gas lines 109 and 110 are normally merely vents through ga~ control pipellne~ from control ~one 50 exhaus~ng at atmospheric pre~sures, but controlling pressure~ at the ob~erved gas ingr~ss positions P and Q down-~t~aam o~ th~ ~ran~l~ion æon~.
Referring to Figure 6, a point of beginning presumes the fluidlcs condition~ in the generally expanding volume down-stream in tr~nsitlon zone S0 are uch that the molten metal power ~tream flows into the zone at 87, past control ports 90 and 91, and is held by the "Coanda wall effect'~ in con~act with wall 100 of channel o~ le~ A of the bifurcat~d egress zone ~erminating transition zone 50 a~ 89. ~ere the m~l~en stream p~8e8 leadln~ edge 103 ~or 102~ of the solid splitter 82 and co~tlnues downstream through channel A to be discharged throu~h r~er 20b ko a pre-determlned o~min~ opera~lon, a secondary holding furnace, or perhap~ to be r~-circulated wi~hin the meltln~ furnace 5.
~ %~
~ en required for use in a seoond Bet of do~nstream production re~uiremen~s or holdin~ conditions, the operator can re-dlxec~ ~he molten metal ~tream enterin~ the transl~lon zonP at 87 ~o the altern~te leg or ch~nn~l B by directing, from the remo~e control location, eha~ a puff of substantially inert ga~ under pr~ure be di~charg~d through gas line 95a ~nd oriflce 90 into control zone 50. Orifice 90 18 po~i~ioned ~ligh~ly downstream of llne 87 in wall lOOo A~ the pressllrized ga~ stream puff impact~ the down~tre~m metal power stream at orifice 90, a turbulent condition re8ult8 in the power stream and a ~eparation bub~le develops. The developed turbulence creates an in~tabllity in the power liquid metal ~tream along the wall 100 causing it to veer towards ch~nnel or leg B. As the power stream contact~ wall 105 of l~g B, the "Coanda or wall effect" take~ over, ~he power stre~m becomes re-attached to wall ld5.
The power metal ~tream continues to 10w in channel B
completely changed in course from channel A a8 it flows pa8t divisional apex 103 of the splitter 82. The now re-dlrected flow of the m~lten met~l continues to flow down~tream ln and through eha~nel B and out riser 20a to a second, And alternative pre-determined mode of functlo~al use of the diver~ed molten metal power str~am.
A8 illustrated in Figure 6, a bi-~table fluidics 8y8t2m i6 designed into the transition zone 50. To re~urn the down-~tream m~tal flow to channel A and riser 20b, a counter puff of compres~ed gas directed through upper support pla~e 3 (Figure 1~, ver~ical drill~ed poas~ 9a and gas line ~it~in~
9ba fro~ the r~ te contxol posltio~ ~nd a compres~ad ga~ 3upply source lnto di~ruptive contact with the power 8tr2~m through ...
2 ~i ~ THU 2-001 ~ 2 ~
oriflce 91 to a8ain rever~e and re~e~tabllsh the original 10w through channel A. The ~ontrol puf of gas ~nters into a ~eparation bubble existant and ad~acent the establi~he~
power metal downstream le~ or ch~nnel (here B~ to çffect the elected power s~ream flow dlrectional h~n~e.
A~ ~he combin~tion of pump ~nd down~tream control mean~
operate: with molten meeals 9 a fail ~afe device mRy be deslreable and u~ed to advanta~e in peclf~c applicatlons.
Figure 7 illustra~es a m~diicatlon of Flgure 6 wherein a more complex modlfication of ~he tran~lt~on zon~ 50 1~ shown.
A mono stable 10w pa~h dominates ~nd prevaila ~hould there be a failure in the inert ga~ control ~upply essential to the dominatioII of a given leg, stream or channel A or B.
Referr~ng to Figures 7, it will be noted that inlet power gas control ports 95a and 96a have been displaced upstream towards the dual volute pu~p as~embly. The effect i8 tO alter slightly the angle of attack of control port~ 90 and 91. ~ote also exit orifice 85 enterR tran~ition zone 50 at. 87 at an offset angle more favorable to ingres~ of the power moltPn me~al stream flow from the pump at pump volute egreas 80 into the transi~ion control zone 50 at 87.
An arcuate CU8p 102 has been eut into and rem~ving the for~er sharp leading edge 103 of splitker 82 entering the transition zone 50. Gu~p 102 extend~ upstream into trangition æone 50 to cause an increa e in lnternal pre~sure on the hlgh pressure side of molten m~tal pow~r stream as it flow6 through expandin~ volume transltion zone 50. Increased lnta,rnal pre~sure lncrease~ the st~bil~ty of .he liquid metal flow direction under po~3ible minor flow variation ~n ies rate and/or pre~sure, for example.
-2~-.~1 '~
Vents 109 and 110 which have been added downstream in the trsnsition zone (near the zone exlt llne At 89) lead through a~soclated ~as conduit mean~ interiorly of control zone 50 and provide mean~ to control ga~ pressures as re~uired at point~ of entry P and ~ in~o downstream leg~ A and B. with-in down~tream limit~ of transition zone 50 at 89.
Note that liquid m~t~l power in~res~ into ~ransition zone 50 at 87 i~ ~lightly asymD~trical or at a slightly of~et an~le. The resultant fluidic ~orces favor fluid flow through channel B, which Eorces will domina~e and mal~tain the control unless a pneuma~ic gas control 81gn~1 through control port 91 i8 con~tantly m~intained.
Thuff, the ba~ic mono~table 10w pattern of the power streEm can be employed should one ~l~ct to proce~s a molten met~l ~tre~m through channel,~ for principal end use~ where no molten me~l over10w problem~ from the egress of riscr 20b occur. For example, flow fro~ ri~r 20b m~y normally re-circulate liquid metal back through the meltin~ or holdin~
furnace 5 to increase the mel~in~ rfite of scr~p metal solids being remelted. For a specific term, however, the pneumatic gas control por~ 91 rould be activated for other specific operations while bPing care~ully ob~erved. Shoult the opera~or's a~ention be dlverted, ~he ~hift back would au~o-n~tical eturn the hot met~l ~treem to ch~nnel B.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A molten metal fluid flow control device functionally adapted to conduct a molten metal stream originating upstream thereof substantially free from insoluble occlusions and under pre-established pressure head and flow conditions through an elected one of two downstream channels which comprises an ingress channel stream entry means into a transition zone of increasing downstream volume which zone terminates in dual outwardly divergent downstream channels, the ingress channel stream entry means, transition zone and downstream channels being elliptical in cross-section wherein the major axis thereof is generally vertical, the upstream intersection of said channels defining an acute angle downstream and within said transition zone, and a stream splitter means the apex of which extends interiorly and upstream into the expanded volume downstream in said transition zone; oppositely disposed gas injection ports into said transition zone upstream of said transition zone but immediately downstream of the initial ingress entry port of said metal power stream into said transition zone, said injection ports adapted to direct an impinging flow of pressurized gas from a remote point of origin of said gas through an elected port to impinge upon said molten metal power stream, activating stream separation from the existing wall effect and re-directing said power stream into the selected alternate one of said two downstream diverging channels.
2. The molten metal fluid flow control device dependent for its operation upon a source of molten metal flow having a relatively constant flow rate, pressure head and freedom from occluded insoluble particulates upstream of the said control which flow control device is characterized by a single fluid ingress channel, dually divergent bifurcated egress channels, the said bifurcated egress channels downstream; and intermediate of said ingress and bifurcated egress channels a fluidics controlled transition zone; the ingress channel stream entry means, transition zone and downstream channels being elliptical in cross-section wherein the major axis thereof is generally vertical, a stream directing exit orifice terminating said single ingress means downstream of said egress and entering said transition zone, oppositely disposed inwardly directed control ports adapted to control differential gas pressures interiorly of said egress zone at said exit orifice, said transition zone expanding in volume downstream to accommodate a single enlarged entry zone into said dual bifurcated downstream egress channels which egress channels separate and diverge at an acute angle, interiorly thereof and forming a triangular splitter element the apex of which extends upstream into the downstream terminus of said expanded transition zone volume; and diagonally opposed gas pressure control ports in said single fluid ingress channel controlled from a remote point of origin and by means of a pressurized gas stream.
3. The molten metal fluid flow control device of Claim 1 wherein the ingress channel stream entry is coextensive and conjoined downstream of a molten metal pumping means.
4. The molten metal fluid flow control device of Claim 1 wherein the ingress channel downstream entry is coextensively associated upstream with the egress channel of a metal melting/holding furnace through a gravity fed molten metal ingress channel upstream thereof.
5. A fluidics operated directional and separation control device means by which a first entry conduit carrying a molten metal downstream under established head and flow-rate from a melting furnace (through an entry port) is controllably diverged into a pre-selected one of two alternate bifurcating downstream conduits as the molten metal is passed downstream through a conjoining transition piece of expanding internal volumes creating a fluidics control zone, said control zone transition piece bifurcated interiorly, downstream and centrally by fixed placement therein of a splitter element of vertical triangular cross-section the apex of said triangle directed upstream determining a point of origin of a controlled diversion of direction of an originating stream into a selected one of said two bifurcated downstream conduits, the entry conduit, downstream conduits and fluidics control zone being elliptical in cross-section wherein the major axis thereof is generally vertical, a pair of diametrically aligned, oppositely disposed compressed gas inlet orifices within a zone of influence of the orifice end of said first stream and conduit, operatively associated therewith and adapted to provide alternative gas pressure ingress to within, and egress from said orifices upon demand and a pair of external conduits associated with a source of compressed gases under remote control injection of pressurized gas through a selected one of said inlet orifices internally impacting said flowing molten metal power stream upstream of said transition piece effecting a fluidic directional control upon the molten metal power stream flowing downstream as it passes through said transition control device.
6. The molten metal fluid flow control device of Claim 1 in which the inlet of the injection ports is displaced upstream.
7. The molten metal fluid flow control device of Claim 2 in which inlets of the gas pressure control ports are displaced upstream.
8. The molten metal fluid flow control device of Claims 1, 2 or 5 in which the splitter includes a cusp at an apex thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US59424184A | 1984-03-28 | 1984-03-28 | |
| US594,241 | 1984-03-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1264126A true CA1264126A (en) | 1990-01-02 |
Family
ID=24378110
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000477632A Expired CA1264126A (en) | 1984-03-28 | 1985-03-27 | Dual volute molten metal pump and selective outlet discriminating means |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1264126A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5597289A (en) | 1995-03-07 | 1997-01-28 | Thut; Bruno H. | Dynamically balanced pump impeller |
| US5622481A (en) * | 1994-11-10 | 1997-04-22 | Thut; Bruno H. | Shaft coupling for a molten metal pump |
| US5676520A (en) * | 1995-06-07 | 1997-10-14 | Thut; Bruno H. | Method and apparatus for inhibiting oxidation in pumps for pumping molten metal |
| US5716195A (en) * | 1995-02-08 | 1998-02-10 | Thut; Bruno H. | Pumps for pumping molten metal |
| US6019576A (en) | 1997-09-22 | 2000-02-01 | Thut; Bruno H. | Pumps for pumping molten metal with a stirring action |
-
1985
- 1985-03-27 CA CA000477632A patent/CA1264126A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5622481A (en) * | 1994-11-10 | 1997-04-22 | Thut; Bruno H. | Shaft coupling for a molten metal pump |
| US5716195A (en) * | 1995-02-08 | 1998-02-10 | Thut; Bruno H. | Pumps for pumping molten metal |
| US5597289A (en) | 1995-03-07 | 1997-01-28 | Thut; Bruno H. | Dynamically balanced pump impeller |
| US5676520A (en) * | 1995-06-07 | 1997-10-14 | Thut; Bruno H. | Method and apparatus for inhibiting oxidation in pumps for pumping molten metal |
| US6019576A (en) | 1997-09-22 | 2000-02-01 | Thut; Bruno H. | Pumps for pumping molten metal with a stirring action |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |