US2547093A - Gas turbine system - Google Patents

Description

April 3, 1951 J. L. RAY

GAS TURBINE- SYSTEM 2 Sheets-Sheet l Filed Nov. 20, 1944 April 3, 1951 J. L. RAY

GAS TURBINE SYSTEM 2 Sheets-Sheet 2 Filed Nov. 20, 1944 Patented Apr. 3, 1951 UNI T ED STAT E S PATE ICE` GAS; v'IURBINE :SY-STEM James L. Ray, EhnGrove, Wis,'assignorlto'AIliS- Chalmers Manufacturingmompany, VMil'wawkee,l Wis., a corporation of Delaware- .AppncationtNoremher 20, 1944s ena1,no, 5641.311

I1' Claims.

.l 'llhisinvention. relates Yto elastic uid, rturbine systems for .developing power by expanding prodoucts of combustion incident torconversionof thermalenergy'into mechanicalenergy andmorepar.-

ticularly to the type,l of. system embodying apparatus for; continuously performing thev steps of releasing a portion of the expanded products; of combustion. l cooling: and then recompressing,v the remainingproducs. of combustion, heating the recompressed productsoi combustionby combiningsame withnewly formedkhighly heatedproducts; of, combustion-` obtained by. burningy fuel'. in a compressed, combustion supporting elasticy uid either'V before, or after such duid is, partially or .wholly mixed with .the recompressedproducts of combustion, andv expanding; the. `resulting mix: ture.'`

In theknownsystems of this type, recompressionoi expanded products of combustionA is ef,- ectedA by a mainA compressing means drivenJ by .oneot the turbines while compression of the coin,- `bustion supporting: elastic fluid is eiected by a separate auxiliary compressing means, driven by another, turbinewhch is mechanically independent of: the. main compressor turbine and also of .the power turbine when such` a turbine is emv-V nloyed; .the auxiliaryl compressor turbine 'being connected either in parallel" or. series flowY ar:- rangement. with .the f main, compressor and power turbines, that s. it either receives, motive. fluid e .fromthe combustion chamber or chamberscsllplplying; the main compressor and4 power turbines, or. it is alow pressureturbinel ope-ratedby motive fluid exhausting from. such` other turbines. In either case,4 both the temperature and the mass low. of motive fluid are similarly simultaneously varied, usually by varying fuel' input to the combustion chamber or chambers in accordance; with changes. in external` loadV or power transmitted, and as, a result, Dart, load eili'ciencies are objectionalily low and; regulation sluggish particularly .with respect, to the, handling of rapidly changing Lloads.

:embodying the invention willbecome readily apparent as the disclosureprogresses and particuflarly points. outA additional features considered ai special importance, andiaccordingly, the inven- 2) Y tion may b e, considered as consisting of the methods and' or the correlations of elements and arrangements o'ff parts asl is more fully setfforthA in the. detailed description and inthe appended claims reierencejbeinghadtoithe accompanyin draivings'inwhichz Fis,v ,1. schematically illustrates a gas turbine system .embodyingtheginvention;

nig. zschematiically illustrates anothersasfiur'- bine system. embodying the inventio11;,

Eig. .3 schematically 'illustrates still another-gas turbinesystlem embodying the, invention..

ReierringtoFi'g, I oijthe drawing it is; seen tha-.t a gas turbine system embodying the invention ,may include a combustion 4chamber'l vhavingaburner portion '2 to which lfuelis supplied from a suitable source (not shown) through a pipe 3 provided with a 'flou/ .'regulatingvalve Ilya startinginotor 6;, a 'rst or main compressoIl 1, acrst or compressor :turbine ik, an 'electric'generator 9, a. secondi or power 'turbine ll, an-auxiliary compressor IL and* an; electric motor It. Starting motor cyandturbines B'an-d H lrnaybe drivingl'y connected with main compressor` 'I1-and with, generator "Bby lany suitable; means-'suelfr'as acom mon shaft' r'ifandieleetric, motor I'Ssmayiberiving'l'y connectedv with 'auxiliary compressorl .i121 by, any suitable 'means'sucir as a common shaft'.

A main conduit:fTand',branch-conduits!Stand "i191 severally Aconneccthe inlets or turbines -8 and .lili with the discharge end of combustion cham- 'loer Landi a conduit TM,A which-"includesheat-exe changing portions, 22, '23 and' '213; connects the exhaust ofturbine lrwith-A the inlet offmain compressor "l: Turbine 'IT exhauststo atmosphere `through a conduit 25; LA conduit '26;Y which' includes a vheat exchanging'portion 21 operatively associated' with lheat- 'exchanging port'i'on- 22 V'of conduitll, connects the,v dischargeofcompressor with the'hurnerend of combustion chamber I anda conduit 28; which ifnjcludes'a-heat exchange n 'ingpportion 29'operativelyassociatedwith heat exrchangingportion A23 of-"conduitil, connectsthe discharge `or auxiliaryccmpressor l2 withfth'e lournerporti'onI 2'v of rCombustioncham-berA The inlet ofcornpressorV I communicates with-- the atmosphere through a conduitill. A coolingfcoilor "the like 32 is Voperativelyy associated Awith4 the vheat exchangingportionf2li/or conduit-Ztl?. Water.

or other suitable cooling rilu-id passesinto andi out of c oil '32througnipipesland 34, respectively:

Excess power 'developed-by the system is conh `verted into' 'electrical energyfingenerator 191` an'clfis transmitted for* useswheredesired `byirneansfo'f a acidosis power line 35 including a switch 36. The armature of motor I3 is connected across power line 35 by means of conductors 31 and 38, the latter including a switch 39. Motor I3 is preferably separately excited by means of field windings 4I and 42 which are in turn separately energized by any suitable means such as batteries 43 and 44, respectively. Starting from one side of battery A43, the energizing circuit for eld winding 4i comprises conductor 46, field winding 4I, con-l ductor 41, rheostat 48, and conductor 49. Start'- ing from one side of battery 44, the energizing circuit for iield winding ft2k comprises conductor 5I, field winding 42, conductor 53, a pair of parallel circuits one of which includes a conductor 54, a rheostat 56 and a conductor 51 and the other of which includes a conductor 58, a rheostat 59 and a conductor 6I, and a conductor 62 connecting conductors 51 and BI with the other side of battery 44.

The position of the movable element 56 of rheostat 48 is controlled by means of a load responsive device comprising a solenoid 53 subjected to oppositely acting forces by means of a spring 54 and a coil 55 forming a part of the secondary circuit of a current transformer 66 associated with power line 35, the arrangement of these parts being such that the field produced by the flow of current through winding 4I is automatically increased and decreased as the load on generator 9, i. e., the electrical energy transmitted through power line 35, decreases andcincreases, respectively. It should therefore be obvious that the control of rheostat 48 in this manner operates to increase and decreasel the speed. of motor I3 as the load on generator 9 increases and decreases, respectively.

The position of the movable element 550i rheostat 56 is controlled by a speed governor 61 operatively associated with shaft I4 and is thereby operated to automatically vary the flow of current through field winding 42 as the speed of compressor 1, turbine 8, etc. increases and decreases. Rheostat 59 is controlled by a speed governor 68 driven from shaft I6 and is operatively associated with the movable elementi vof rheostat 59 by means of a speed-limiting lostmotion connection 69. Consequently, rheostat I59 is operated to automatically vary the ow of Vcurrent through field winding 42 only in the event `the speed of motor I3 exceeds a predetermined maximum. In this connection, it should be noted that since rheostats 56 and 59 are connected in parallel relation between iield winding 42 and .battery 44, these two rheostats are jointly and severally operative to vary the ow of current through field winding 42 as determined by the movements of their actuating governors 61 and 68, respectively.

The relation of eld windings 4I and 42 and the energizing control thereof afforded by rheostats 48, 56 and 59 is/such that the speed of motor I3 and thereby the quantity of air delivered by auxiliary compressor I2 to the burner portion 2 of combustion chamber I is normally increased and decreased as the load on the system, represented in this case by the transmission of electrical energy through power line 35, increases vand decreases, respectively, that in the event the speed of compressor 1, turbine 8, etc. varies in response to a change in the quantity of air being delivered to combustion chamber I by `auxiliary compressor I2, or for any other reason, rheostat 56-Yis operatedv by governor 61 to effect a compensating change in the speed of motor I3 and compressor I2, that in the event the speed of motor I3 and compressor I2 should for any reason exceed a predetermined maximum, rheostat 59 is operated by governor 68 to effect a reduction in the speed of motor I3, and that when the load on generator 9 is zero or the switch 35 in power line 35 is opened, the movable element of rheostat 48 is positioned against stop 10 by the action of spring 6d to maintain motor I3 operating at a minimum speed rendering auxiliary compressor I2 effective to supply combustion chamber I With a quantity of air sufficient for idling or no load operation.

Operation of this system is initiated in the usual manner by means of starting motor 6, and once the system is up to speed and motor I3 energized by closing switch 39, combustion may be initiated and the operation of the starting motor, which may be of any desired type, terminated. During normal operation, the temperature of the mixture of newly formed and recompressed products of combustion leaving combustion chamber I through conduit I1 is maintained substantially constant at the highest value permissible for continuous operation by means of a temperature responsive device 1I operatively connected with fuel flow regulating valve 4 by any suitable means, such as a lever 15, to effect compensating changes in its position and thereby corresponding changes in the temperature of the newly formed products of combustion. Obviously, a variation in the temperature of the newly formed products of combustion effects a corresponding change in the resulting mixture of newly formed and recompressed products of combustion. Moreover, it should also be obvious that since the speed of auxiliary compressor I2 is varied in accordance with changes in load, the quantity and the pressure of the combustion supporting air delivered to combustion chamber I is likewise varied as is also the pressure and density of the resulting motive fluid.

Consequently, it should now be apparent that in operation, the quantity of compressed'v combustion supportingv elastic fluid and thereby the mass flow of the mixture of recompressed and newly formed products of combustion are varied in accordance with changes in load or power requirements, and the fuel input is also varied substantially simultaneously so as to maintain the temperature of the mixture prior to expansion substantially constant throughout the normal range of power development.

Referring to Fig. 2, it is seen that another embodiment of the invention may include a main compressor 12, a high pressure main compressor turbine 13, a low pressure power turbine 14, an electric generator 15, an auxiliary compressor 11, a low pressure auxiliary compressor turbine 18, a main combustion chamber 19 having a burner portion SI to which fuel is supplied from a suitable source (not shown) through a pipe l82 provided with a flow regulating valve 83, a

reheat combustion chamber 93 having a burner portion 9i to which fuel is supplied through another branch sZ of pipe 62 which is also provided with a pair of flow regulating valves 93 and 94.

Branch pipes 81 and 92I are connected with pipe 82 on the'upstream side of valve 83 and on the open main fuel valve 85 and initiate' combustion in primary chamber 19 whereupon operation of starting motor 95 may be terminated. Low pressure turbines 1d and 18 kare both developing power due to the passage therethrough oi the combustion gases issuing from high pressure turn-ine 1t and consequently auxiliary compressoi' 11 is now delivering combustion supporting elastic fluid to the burner portions of primary and reheat combustion chambers 19, 8d and 9,9. Consequently manually operated fuel ow control valve ad in pipe 31 can now be opened and combustion initiated in reheat combustion chamber 81|. If the valves in atmospheric inlet l2|`i and branch conduit |25 have been opened, they may be closed either before or after initiating combustion in reheat chamber Sil. The system is now operating under idling or no load conditions with the temperature responsive devices |21 and |28 operating to maintain the temperature of the mixture of newly formed and recompressed products of combustion entering high pressure turbine 13 and the temperature of the mixture of newly formed and partially expanded products of combustion entering low pressure turbine 1li substantially constant at values commensurate with optimum thermal efciency.

As previously indicated, automatically actuated fuel valve illi is closed and bypass H3 in conduit ||1 is partially open to the extent determined by the position of stop |35 which is in turn preferably so located that the flow of motive fluid through low pressure turbine 18 and the power and speed developed thereby is suiicient for stable idling operation and that the system can be started, if desired, without the aid of the valve controlled atmospheric inlet v|29 to main compressor 12 and of the valve controlled branch conduit |25 connecting conduit 98 with the'burner portion 8| of primary combustion chamber 19. If desired, an auxiliary starting motor |66 on shaft 91 may also be utilized for starting purposes. If it is now desired to carry load, switch |39 in power line |32 is closed whereupon the resulting movement of solenoid |38 is rendered operative to actuate lever |33 in a clockwise direction as the load increases thereby moving bypass valve ||8 to its fully closed position and opening fuel valve S4 to increase reheat input to the partially expanded motive fluid entering reheat combustion chamber 9|), the maximum temperature of the fluid entering low pressure turbine 18 being limited by temperature responsive device |29. Upon a decrease in load, the combined action of spring |42 and piston lllt'moves lever |33 in a counterclockwise direction thereby moving fuel valve 94 toward its fully closed position, and if the decrease in load is suiiicient, valve 94 is fully closed and bypass valve H8 is opened until a further opening movement is prevented by stop Consequently, both the quantity and the temperature of the motive fluid passing through low pressure turbine 18 and thereby its speed and power and the quantity and pressure of the air delivered to the burner portions 8|, 86 and 9| of combustion chambers 19, Eli and 98 by auxiliary compressor 1'! is varied in accordance with changes in load. i. e in accordance with power requirements. Moreover, temperature responsive device |21 operates to vary fuel input to primary combustion chamber 19 so as to maintain the temperature of the mixture of newly formed and recompressed products of combustion substantially constant prior to the expansion thereof, and it should therefore be obvious that in general the system of Fig. 2 airords at least all of the advantages present in the system or Fig. l.

Referring to Fig. 3, it is seen that still another embodiment of the invention may include a main compressor |53, a main turbine |555, an eiectric generator |56, an auxiliary compressor |51, a low pressure auxiliary compressor turbine` |8, a primary combustion chamber |59 having a burner portion |6| to which fuel is supplied from a suitable source (not shown) through a pipe |52 provided with a flow regulating valve |33, and a reheat combustion chamber |64 having a burner portion |66 to which fuel is supplied through a branch pipe |61 provided with a now regulating valve |8 and a manually operated valve |65. Branch pipe |61 is also provided with an additional flow regulating valve |69 and is connected with pipe |62 on the upstream side of valve |63 whereby the flow of fuel to burner portions |6| and |66 can be severally controlled as desired. Pipe |62 is also provided with a manually operative main control valve |1|l disposed in upstream relation with respect to branch pipe |61. A starting motor i'il and the turbine |6|l may be drivingly connected with main compressor |53 and generator |56 by any suitable means such as a common shaft |12. Auxiliary turbine |58 may be drivingly connected with compressor |51 by any suitab--e means such as a common shaft |13.

A conduit |13 which includes a heat exchanging portion |14, connects the discharge of main compressor |53 with the burner end of combustion chamber |59 and a conduit |16, which includes a heat exchanging portion |11, connects the high pressure discharge portion of auxiliary compressor |51 with the burner portion |6| of primary combustion chamber |59. A 'conduit |18, which includes a heat exchanging portion |19, connects a low ,pressure discharge portion of auxiliary compressor |51 with the burner portion |66 of reheat combustion chamber It. A conduit |8| connects the discharge end of primary combustion chamber |59 with the inlet of high pressure turbine |515 and a conduit |82, which includes a heat exchanging portion |83 operatively associated with the heat exchanging portions |14, |11 and |19 of conduits |13, |16 and |18 and a heat exchanging portion |84 operatively associated with a cooling coil |86 having inlet and outlet connections |81 and |88, respectively, connects the exhaust of high pressure turbine |56 with the inlet of main compressor |53. A bleeder conduit |89 connects an intermediate pressure exhaust of high pressure turbine |54 with the burner end of reheat combustion chamber |54 and a conduit |9 connects the discharge of reheat combustion chamber |64 with the inlet of low pressure auxiliary turbine |58. A conduit |92, which includes a heat `eX changing portion |93 operatively associated with one or more of lthe heat exchanging portion |14, |11, |19 of conduits |13, |16 and |18, places the exhaust of low pressure turbine |58 in cornmunioation with the atmosphere.

Fuel flow regulating valve |63 is operatively connected with a temperature responsive device |94 which is in turn operativelyassociated with primary combustion chamber |59,'the arrangement of these parts being such that flow regulating valve |63 is positioned to effect compensating changes in fuel input to the burner portion 16| of `'combustion chamber |59 .in `order tomain- .tain Ythe temperature .of -the mixture -.of newly formed vand -recompressed products .of combustion entering high pressure yturbine |54 substan- -tially constant .at ya selected .maximum value commensurate `with optimum thermal efliciency. Fuel flow regulating valve |68 vis normally maintained its -fullyopen 4position and is closed or Lpartially closed -in the event the temperature of the reheated `mixture of newly formed and partially expanded products of combustion 4en- ;ter-ing .turbine |58 exceeds-a :predetermined maxivmum by means of `a temperature responsive -device |96 V.which is operatively associated with re- Azheat combustion chamber |64 -and operatively connected with valve |68 by means including a .lost-motion connection 91..

The position of fuel flowregulating valve `|69 is controlled `by the `joint action of speed and load responsive devices operatively .associated with ^shaft |72 and with generator power line |98 which includes a control switch |99, respectively, thev control apparatus in this case lcomprising a Ylever Ztl! fulcrumed intermediate its Vends and having .one end pivotally connected with valve -.|6'9, ,a solenoid -22, which is voperatively associ- `ated with a coil12c3 'forming-part ofthe secondary :circuit .of a current transformer 2&4 which is in .turn .operatively associated with power line |98, .has one end pivotally connected with the other :endof lever 2i||, a spring .2.06 having one end `also `connected with the other end Aof lever 20l| .in-opposite force-,producing relation with respect 'to :solenoid 22 and having `its Lopposite end lconnected with speed governor 297| which is inturn #operatively associated with :shaft |`|2, The arrangement of these parts :is such Athat a downward movement of solenoid v2112 is resisted by spring 296, that the tension of spring 206 .increases and decreases as the 'speed of shaft |12 .increases and decreases, respectively, that an increase .in the power Atransmitted through line A|98 results 1in clockwise movement oflever 201|, that a 'decrease in the power transmitted results in a countercloclnvise movement of lever 29|, and that if a change in load, i. e., a change in the .power transmitted through line |98, is accom- :panied by a change in the speed of shaft |12, governor 2M modifies the action of solenoid 20-2.

When the system is shut down, manually op- -ierated fuel valves |65 and |10 are closed .as is also fuel flow regulating valve |59 and the switch v|99 in ,power line 198 is yopen. Conseouently, all vthat has to be done in order -to start the system .is to energize starting vmotor kand bring the main .unitcomprising compressor |53 -and high pressure turbine |54 .up toa self-operating speed whereupon manual .fuel valve V1.6 can be .opened and combustion initiated xin the burner portion .|64 of .primary combustion chamber |59 which is 'supplied with combustion supporting air due to the operation of .auxiliary compressor |51 .effooted 4by the passage of partially expanded gas through low ,pressure Aturbine |58, and if desired, by the aid of an 4auxiliary.starting motor |75 on .shaft |13. The initiation of .combustion increases the energycontent of the-motive flu-id and there- Yby .the power developed by turbines |54 and y'|58 sufficient `for self-operation under no load or idling .conditions without.` the aid of reheat combustionchamber |564, .and consequently, the .operation of-starting Ymotor .may .be terminated as soon or shortly after combustion has been .initiated in ,primary chamber |59. All `that now has. to -be done in order `to condition the system for .carrying .load is to .open vmanual valve .in .fuel .line |51., .which rendersigovernor ,`20`| effective lto .control .'fuel 'input to .reheat combustion chamber 'I'.Sii and .thereby thespee'd of 'low pressure turbine .|58 and auxiliary compressor [Else as to maintain `thespeed of themain unit comprising main compressor |53, high pressure turbine r|54 and generator 'f5.6 substantiallyfcon- .stant ata .predetermined desired value, and to lthen close switch .|99 .in power line |98.

.The closure of switch |99 places valve |69 Vunder the joint ycontrol of speed governor 201 and load responsive solenoid i202 .and consequently thespced oflow pressure .turbine Ifllfand of auxiliary compressor |57 will be normally varied in accordance with lthe .speed and power .requirements of the main unit. However, if for any reason the .temperature -of the .motive fluid entering .low pressure .turbine n|53 shouldbecome excessive, .temperature .responsive device 19S will A.effect .a closing .or parlt'ial closing o'f fuel valve T68. During .normal operation, the temperature ofthe motive .fluid entering high pressure turbine |54 will be .maintained substantially constant at the maximum value .permissible for continuo-us operation by the action of temperature responsive device |94, and it should therefore be obvious tthat this system also operates to vary the quan- .tity -of compressed, 'combustion supporting elastic fluid delivered to the burner .portion '|61 'oT .primary combustion chamber 59 and'thereby 'the .mass flow of the mixture o'f recompr'ess'ed and newly formed products-of 'combustion in accordance with power requirements, .and 'to substanl`.tially simultaneously vary the fuel "input'to 'the primary combustion chamber so as to 'maintain the y.temperature of such 'mixture substantially constant .prior `to 'its vexpansion in lLhigh 'pressure turbine |54. v

In both the systems shown 'in'Figs 2 and 3, :the compressed, combustion supporting elastic fluil delivered 'to the 'reheat combustion chamber 'or chambers is maintained at a ,pressure commensurate with'the pressure ofthe partially expanded mixture of newly fform'ed and recompressed .products of combustion supplied 'to vsuch chamib'ers from the .high pressure turbine -or turbines. Moreover, in all vof 'the systems herein described', the main compressor and power 'turbine or turbines are operated` at a substantially constant speed and temperature, thepower developed being varied 'by changing the mass :flow 'and density of the .motive fluid Vin 'accordance with changes in load. Consequently, the 'overall thermal 'efciency o'f the main unit is maintained substantially constantthroughout then'o'rmalload range, and since the power developed andutilized by the main unit may be yas 'much or'm'ore than O58 o the total power developed by both `the main an'd auxiliary units, the overall thermal ef'ciencyol the system is materially 'improved by'maintain- 'ing conditions conducive to obtaining -optimum thermal eciency for the main unit. In addition, the provision of an auxiliary, makeup 'compresser unit which operates independently of the main unit with respect to power 'andspee'd developed alfords 'better .regulation particularly with respect to part load' operation and with respect to the handling of rapidly changing loads.

The invention embodies features-of general application although. ofparticulary advantage when applied. to vsystems embodying apparatus for continuously perorm'ingthe steps of releasing a portionV of "thev expanded products of combustion. cooling andV then .recompressing the remaining ii products of combustion, heating the recompressed products of combustion by combining same with newly formed, highly heated products of combustion obtained by burning fuel in a compressed', combustion supporting elastic iiuid either before or after such fluid is partially or wholly mixed with the recompressed products of combustion, and expanding rthe resulting mixture, and it should therefore be understood that it is not desired to limit the invention to the exact modes of operation and systems herein shown and described for purposes of illustration as various modifications within the scope of the appended claims may occur to persons skilled in the art.

y It is claimed and desired to secure by Letters Patent:

' 1. In a method of developing power by expanding products of combustion'incident to conversion of thermal energy into mechanical energy including the continuously performed steps of releasing a portion of the expanded products of combustion, cooling and then recompressing the remaining products of combustion, heating the recompressed products of combustion by combining same with newly formed, highly heated products of combustion obtained by burning fuel in a compressed, combustion supporting elastic fluid before or after such uid is partially or wholly mixed with the recompressed products of combustion, and expanding the resulting mixture; the improvement comprising the steps of directly varying only the quantity of compressed, combustion supporting elastic fluid and thereby the mass flow of the mixture of recompressed and newly formed products of combustion in accordance with power requirements, and substantially simultaneously varying fuel input so as to maintain the temperature of s-uch mixture prior to the expansion thereof approximately constant throughout the normal range of power development. i

2. In a method of developing power by expanding products of combustion Vincident to con- ',version of thermal energy into mechanical energy including the continuously performed steps oi releasing a portion of the expanded products of combustion, cooling and then recompressing the remaining products of combustion, compressing a combustion supporting elastic fluid, combusting -fuel in at least a portion of such fluid, mixing the newly formed. products of combustion with the recompressed products of combustion to heat the flatter, and expanding the resulting mixture; the improvement comprising the steps of directly varying only the quantity of compressed combustion supporting elastic fiuid and thereby the mass flow of the mixture of recompressed and newly formed products of combustion in accordance with changes in power requirements, and substantially simultaneously varying fuel input so as to maintain the temperature of such mixture prior to the expansion thereof approximately constant throughout the normal range of power development.

3. In operating a power developing system embodying a main elastic fluid compressing means, a plurality of turbine means including at least one turbine or turbine section having its exhaust connected with the inlet of the main compressing means and at least another turbine or turbine section exhausting to atmosphere, a driving connection between at least one of the turbines or turbine sections and the main compressingmeans, a separately driven auxiliary lcompressing means having its inlet connected with a source of combustion supporting elastic fluid, means for conducting elastic iiuid discharged from the main and auxiliary compressing means to all of said turbines, andfmeans for heating the compressed elastic fluid passing into said turbines or turbine sections by combusting fuel in such fluid or a constituent thereof; the method of improving thermal eciency and accelerating characteristics comprising the steps of directly varying only the speed of the auxiliary compressing means in accordance with changes in power requirements of said turbines, and substantially simultaneously varying the heat input to the compressed elastic iiuid so as to maintain the temperature of at least that portion of the fluid entering `the turbinev or turbine section driving the main compressing means approximately constant prior to the expansion thereof throughout the normal range of power development. y

4f. ,In operating a power developing system embodying a main elastic uid compressing means, a plurality Yof turbine means including at least one turbine or turbine section having its exhaust kconnected with the inlet of the main compressing means and at least another turbine or turbine section exhausting to atmosphere, a driving connection between at least one of said turbines or turbine sections and the main compressing means, means for conducting recompressed elastic uid discharged from ythe main compressing means to all of said turbines or turbine sections comprising at least one combustion chamber having a burner portion adapted to producefnewly formed products of combustion and a mixing portion in which newly formed products of combustion are Vcombined with recompressed elastic fluid, and

an auxiliary compressing means' mechanically independent of said turbine means and having an inlet connected witha source of combustion supporting elastic iiuid and an outlet connected with the burner portion of said combustion chamber; the method of improving thermal efficiency and accelerating characteristics cmprising the steps of directly varying only the speed of the auxiliary compressing means in accordance with changes in the, power requirements of said turbines, and substantially simultaneously varying the temperature of the newly formed products of combustion and thereby the temperature of the mixture of newly formed products of combustion and recompressed elastic fluid entering said tur'- bines or turbine sections so as to maintain the inlet temperature of such mixture approximately constant prior to the expansion thereof throughout the normal range of power development.

5. In an elastic fluid turbine power system embodying a main elastic fluid compressing means, a plurality of turbine means including Aat least lone turbine means having its exhaust convnected with the inlet of said main compressing means and at least another turbine means exhausting to atmosphere, a driving connection between at least one of said turbine means and said main compressing means, means for conducting recompressed elastic fluid discharged from said main compressing means to all of said turbine means comprising at least one combustion chamber including a burner portion adapted to produce newly formed products of combustion and a mixing portion in which newly formedfproducts of combustion are combined with recompressed elastic uid, an auxiliary compressing means operable separately from the turbine means which is drivingly connected with said main fluid comcasacca pressing-means iland having an iin'let :communie sive to changes in the excess power'beingidevel- "ope'd by said turbine means for increasing :and -rdecreas'ingthe speed of the auxiliary compressing "meanszas :the lpower developed increases and `de- 'fcreases respectively, and 4-a second Vcontrol revfspcnsive Lto the 'temperature :ci the elasticiiiuid "passing into :the lturbine `means ior varying Stue jlinputitofsaid burner-portion-'so as to maintain'fthe temperature :o'f fthe lmixture fof newly/"formed products :of "combustion and -recompressed elastic lluid -lapproximately constant :prior to ythe fervparisien `thereof as the 4power :deuel'opedwnies nthroughout thevnor-mal load range.

T6. 'An ela'stic V4duid fturbinerpctver .'sy'stemfcorrn pricing :a :main elastic iiuid Ycompressing-'mearIs'fa plurali-'typt :separateiyfoperable turbines 'includ- "ling sa first -turbine having v`an v'exlfiaust portion e 'connected Withthe inlet-of saidmainfcompressing means and A=a A'second turbine exhausting lto `at- `mesnil-1ere, 'a drivingconnection-betweensaid "iii-st turbine land -said main compressi-ng means, a sepuusate l'auxiliary confipressing finca-ns hav-ing 2an inlet communicating with .a source rof combustion supporting elastic iluid, a drh/'ingiconneotion between said second turbine vand said auxiliary icompressing means, Ameans 'for conducting recompressed r`:elastic `fluid discharged Trom said 'main `:compressing:means `to said and second lturbines f'ior f expansion vin succession 'ftherein comprising V'separate combustion chambers respectively disposed inf-upstream relation tofsaid turliin'es, said `combustion chambers feachiinc'luding a burner 'portion adapted `to pro-duce `newiy .formed products of combustion and a'mixingpcrtion 1in rwhich newly forrned 'products of com- `oustion fare combined with recompressed elastic fuid, means `for Yconductingv compressed :combustion'fsupporting 'elastic fluid discharged from 'said l.auxiliary compressing means to the burner porfofea'chfof 4said `comlmistion chambers, 7and means for delivering #fuel tothe burnerip'ortion of feacl-ifof saidfcombustion chambers, means for improving thermal efciency and regulating characteristics comprising a 'rst control responsive vato' changes the excess :power developedby 'the system for increasing and decreasing ithe "quan-V tity of fuel delivered to the -burner 4:portion of the combustion chamber in direct association with fsai-d second turbine-'sons to varythe speed .Ufrsaid auxiliary compressing `means as .the 'expower developed increasesgand decreases, retslpectively, and "a second contini responsive 'to the temperature 'of the elasticfluid passing .into *said :first'turbine'lor varyingthe 'quantityo'iuel "delivered to the'bnrnerp'ortion `of the combus tion chamber in direct association with said rst turbine so as to maintain the temperature of the Vmixture of newly formed products of combustion and recompressed elastic iuid entering said iirst turbine approximately constant as the excess power developed by the system varies throughout the normal range of operation.

'7. An elastic uid turbine power system comprising a main elastic fluid compressing means, a separate auxiliary compressing means having an inlet communicating with a source of combustion supporting elastic fluid, a plurality of rst 14 vtuibin'e meansincluding zatleastzonezturbineifar turbine section driyingly connected said main compressing -means,.ra Ysecond-.turbine:means exhaustingto atmosphereand operableseparately v'fromrsaid iirst .turbine means, a dri-ving;c0nnec Ation between said second turbine zmeansandrisaid auxiliary compressing rmeans, means "severally connecting Vzt-he inlet of #said .main I'compressing means 'andlthe'iinlet of said :seconditurbine lmeans with exhaustportion's A`of .said first .turbine means,

saidrconnection:between'said irstzand secondiure- `bi'nemeans lincluding .a combustion chamber'havying faburnerportion adapted to .produce :newly ormediproductscf combustionand ia'mix'ing por- '.tion'in which `newly formed '.productscf combusitien .are combined =With,;motive fluid exhausting from said fiirst :turbine means, means for conducting irecempressed motive 'luid .discharged fromlsaid main :compressing :means to .saidirs't tur-.binemeans .comprising at least one combusltion :chamber including 'a Iburner .portion ad apte'd :to .produce newlyformed products fofcombust-ion .zand a mixing porti'on'in kwhich newly formed .products :of combustionare combined with recomwpressedlmotive Aiiuid, andcmeans connecting irelatively high'and .low pressure .discharge portions of said .auxiliary compressing'imeans with the zcurner portions of the combustion :chambers .supplying .motive liiuid'to the inlets `of :said firstfr'and :second turbine means, -respectively.

S. Anfielastic .duid turbine power system 1Compricing a `main elasticciuid .compressing'imeana-'ra iseparate auxiliary compressing'means .iiavingan inlet communicatnig with fa Isource tof '.:combus- @tion .supporting elastic duid a 'i'luralyaof rst turbine mea-ns I including at leastsone Y2higl11presturbine or turbinefsectionfandp'at .least ione low 'pressure turbine -or v'tuiieine "section, Akfa adriving connection .between :at .least 'one .'.o'fsaid zrst turbine means and said main compressing fmea'n's, ase'cond turbineineans exhau'stingfto atmosphere and operable `separately from said iirst turbine m-eansz'a driving :connection .between said 4second turbine means rand said auxiliary .compressing means, imeans `connecting the eichau'st `:of "said low pressuretnrbine or lturbine section with 'the inlet of .said .main compressing means, :means .severally connecting the inlet of said glow "pressure turbine ror turbine section .and "the .finlet :of :said second iturbine means with :an .exhaust pory-tionof `said high .pressure turbine -or turbine .esecitiongsaid connection between said `high pressure turbine for turbine section and :said second -tur-- vbine means including VVa :combustion chamberihaving 5a burner V'portion adapted 'to 4,produce newly formed products .ci 'combustiontand 'a mixing 4portion .in which newly io'rmed products of combusftidnfarre combined with motive fluid exhausting :from saidhi'gh pressure tu-rl'i'ine or turbine rsec.- ltion, means for conducting `recompressed motive fluid `discharged ffrom said main compressing means 'to Asaid -rst 'turbine Imeans comprising V1at .least one combustion chamber cluding a burner portion adapted to produce newly formed products of combustion and a mixing portion in which newly formed products of combustion are come Y bined with recompressed motive fluid, and means connecting relatively high and low pressure discharge portions of said auxiliary compressing means with the burner portions of the combustion chambers associated with said first and said second turbine means, respectively.

9. An elastic duid turbine power system comprising a main elastic fluid compressing means, a

' separate auxiliary compressing means having an -said second turbine means and said auxiliary compressing means, means connecting the exhaust of said low pressure turbine or turbine section'with the inlet of said main compressing means, means including separate combustion chambers severally connecting the inlet of said low pressure turbine or turbine section and the inlet of said second turbine means with an exhaust portion of said high pressure turbine r turbine section, said separate combustion chambers each having a burner portion adapted to yproduce newly formed products of combustion and a mixing portion in which newly formed products of combustion are combined with motive iiuid exhausting from said high pressure turbine 0r turbine section, means for conducting recompressed motive iiuid discharged from said main vcompressing means to said high pressure turbine orturbine section comprising at least one combustion chamber including a burner portion adapted to produce newly formed products of 'combustion and a mixing portion in which newly :formed products of combustion are combined with recompressed motive iluid, and means connecting relatively high and low pressure discharge portions of said auxiliary compressing means with the burner portions of the combustion Achambers associatedwith said high and low pressure turbine portions, respectively, of said iirst and second turbine means.

10. An elastic fluid turbine power system comprising a main elastic fluid compressing means,

a high pressure turbine or turbine section, at least two low pressure turbines or turbine sections including at least one turbine or turbine Ysection which exhausts to atmosphere, means connecting the exhaust of at least another one of said low pressure turbines or turbine sections with the inlet of said main compressing means,

means including a primary combustion chamber connecting the discharge of said main compressing means with the inlet of said high pressure turbine or turbine section, means including a reheat combustion chamber connecting the exhaust of said high pressure turbine or turbine section with at least said one of said low pressure turbines or turbine sections exhausting to atmosphere, said combustion chambers each including a -burner portion adapted to produce newly formed products of combustion and a mixing portion in which newly formed products of combustion are combined with the motive fluid delivered thereto, an auxiliary compressing means having 16 an inlet connected with a source of combustion supporting elastic fluid, and means connecting relatively high and low pressure discharge portions of said auxiliary compressing means with the burner portionsof said primary and reheat combustion chambers, respectively.

l1. In an elastic fluid turbine power system `embodying a main elastic duid compressing means, a plurality of turbine means including at least one turbine means having its exhaust connected with the inlet of said main compressing means and at least another turbine means exhausting to atmosphere, a driving connection between at least one of said turbine means and said main compressing means, means for con:- ducting recompressed elastic fluid discharged from said main compressing means to all of said turbine jmeans comprising at least one com'- bustion chamber including a burner portion adapted to product newly formed products of combustion and a mixing portion in which newly formed products of combustion are Combined with recompressed elastic uid, an auxiliary compressing means operable separately from the tur.- bine means drivingly connected with said main fluid compressing means and having an inlet communicating with a source of combustion supporting elastic uid and an outlet connected with the burner portion of said combustion chamber, a separate source of power for driving said auxiliary compressing means, means for delivering fuel to the burner portion of said combustion chamber means, and means for improving thermal efciency and accelerating characteristics of the system comprising a rst control responsive to changes in the excess powerbeing developed by said turbine means for separately controlling said separate source of power to increase and decrease the speed of the auxiliary compressing means as said excess power developed increases and decreases respectively, and a second control responsive to the temperature of the elastic fluid passing into the turbine means for varying fuel input to said burner portion so as to maintain the temperature of the mixture of newly formed products of combustion and recompressed elastic fluid approximately constant prior to the expansion thereof as the power developed varies throughout the normal load range.

JAMES L. RAY.

REFERENCES CITED The following references are of record 'in the file of this patent:

UNITED STATES PATENTS y v Date

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