US2940394A - Turbine pump - Google Patents

Description

June 14, 1960 G. E. MosuRE 2,940,394

TURBINE PUMP Filed 001'.. 3, 1958 F IGA.

PUMP PRESSURE RISE RS I.

United States Patent O TURBINE PUMP Garrett E. Mosure, Sepulveda, Calif., assignor to West- Filed Oct. 3, 1958, Ser. No. 765,178

6 Claims. (Cl. 10S-2) This invention relates to rotary pumps of the turbine or regenerative type and has for an object to provide an improved pump of this type.

Turbine pumps have high pressure -developing capacity even at relatively low speed, because of the recirculating action between the blades 'of the impeller and the walls of the pressure developing chamber, as well as the resultant accumulation of energy in the fluid during its travel between the suction' inlet and discharge outlet. However, the maximum fuel flow (delivery) capacity of the pump isattained at relatively low speeds and may be insuicient for many applications.

In -view of the above, it is a further object to provide a. uid pump ofthe turbine type which has a high pressure developing capacity at relatively low speeds and has a high fuel delivery capacity at higher speeds.

Another object of the invention is to provide a duid pump of the turbine type in which the Huid llow and fluid pressure developing characteristics of the pump are modified in response to a predetermined speed signal.

In accordance with the invention, there is provided a turbine pump having an impeller provided with a pair of annular rows of radial blades and disposed within a housing which, jointly therewith, defines a symmetrical annual pressure developing chamber or passageway. The pump is further provided with the usual peripherally spaced primary suction inlet and primary discharge outlet for the pressure developing chamber.

A secondary suction inlet and a secondary discharge outlet are also provided for the chamber and are disposed intermediate the primary inlet and outlet. The secondary inlet and outlet are blocked in the low speed range by valve structure, so that the pump operates in the conventional manner in the low speed range to deliver uid at adequate pressure and ow rate.

Means responsive to speed of the impeller is provided for actuating the valve structure to the unblocking position at a predetermined speed value. Accordingly, in the upper speed range, iiuid is admitted to the pressure developing chamber by the primary and secondary suction inlets and delivered therefrom at increased flow rate by the primary and secondary discharge outlets. Since, in .the upper speed range, the length of the duid path through the chamber is considerably reduced, the pressure developed by the fluid owing therethrough is considerably less than that developed by a conventional turbine pump in the same speed range. However, since the pump inherently has excessive' pressure developing capacity, the -developed pressure is more than adequate for practical applications.

One of the most notable applications, for example, is in a gas turbine engine wherein the pump is driven by the engine rotor for supplying liquid fuel thereto within prescribed pressure and flow rate ranges for combustion purposes at varying rates' of speed (for example, from about 1400 r.p.m. to 12,500 r.p.m.). In such an appliice cation, the speed responsive means may be desirably adjusted to unblock the secondary inlet and outlet of the pump at about 5000 r.p.m., which speed is the idling speed of the engine.

The above and other objects are eected by the invention as will be apparent from the following description taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. l is a diagrammatic view illustrating a typical gas turbine engine having a fuel pump embodying the invention, the pump being shown in one operative' positron;

Fig. 2 is a View showing the pump in another operative position;

Fig. 3 is an enlarged sectional view taken on line liI--III of Fig. 2; and

Fg. 4 is a chart showing a number of characteristic operating curves.

Referring to the drawing in detail, especially Fig. 1, there is shown a gas turbine engine 1i) equipped with a fuel pump 12 of the turbine type, formed in accordance with the invention.

The gas turbine engine 10 forms no part of the invention and has been shown merely to illustrate a typical Y application for the pump. In the example shown, the

' gas turbine engine is of the vwell-known axial flow aviation turbojet type having a tubular outer casing 13 within which are disposed an axial ow compressor 14 having a rotor 15, fuel combustion apparatus including an annular combustion chamber 16 equipped with a plurality of fuel injecting nozzles 17, and an axial ow gas turbine 1S having a rotor 19 drivingly connected to the compressor rotor 15 by a drive shaft 20. The casing 13 denes a forwardly directed air intake opening 21 and a rearwardly directed exhaust nozzle 22.

In operation, fuel is admitted to the fuel injecting nozzles 17 by a delivery conduit 23 and injected into the combustion chamber 16 Where it is ignited in the presence of pressurized air to provide -hot motive gases for the turbine 18. After partial expansion in the turbine to drive the turbine rotor 19, the gases yare ejected through the exhaust nozzle 22 in -a rearwardly directed propulsive jet. The turbine rotor, in turn, drives the compressor rotor 15, whereby atmospheric air is drawn through the air intake 21 and delivered in a pressurized state to the combustion apparatus to complete the cycle.

The fuel pump 12 is provided with an impeller 25 having a pair of annular rows of circumferentially spaced radial blades 26 and a housing 27 tting snugly about the impeller and jointly therewith defining an annular duid pressure developing chamber 28 of symmetrical shape. The impeller 25 is carried by a rotatably supported drive shaft 29 which is drivingly connected to the turbojet engine rotor aggregate by gearing 3G.

Hence, the impeller 25 is rotated at varying speeds as determined by the speed of the turbojet engine, in one direction, for example, clockwise, as illustrated.

'Ehe housing 27 provides a primary suction inlet 31, connected to a suitable fuel supply source 32 by conduit 53, and a primary discharge outlet 34, connected to the engine fuel delivery conduit 23. The discharge outlet 34 is peripherally spaced Ifrom the suction inlet 311 to a large angular degree in the direction of impeller rotation, and in the example shown, the angular spacing is about 250 degrees.

in addition thereto, the pump housing 27 is further provided with annular wall structure 35 deuing a bypass passageway 36, communicating at its downstream end with the delivery conduit 23, and at its upstream end with a secondary discharge outlet 37. Extending through the bypass passageway 36 is a hollow strut 33 controlling the' secondary suction intake 39 and the second-v ary discharge outlet 37, respectively. The valves .41 and 42 are formed lin such a manner that when they are de# energized their valve members 43 andi 44 are disposed in the iiow blocking position, as illustratedingFig. 1, thereby preventing fuel flow into the suction intake 39 and from the discharge outlet Y37. Hence, with thevalves'in this position, the fuel from the supply conduit33V flowsV through the'primaryV suction intakecfl into the pump chamber 28 and traverses an angular path'o 31361113250 de'- grecs before ejection throughthe: primary dischauge outlet 34. Y

The solenoid valvesV 414 and 412! are;controllori by an responsive fto the rotational speed ofthe impeller shaft 2?. The speed responsive switch 46 is'connected into defining a secondary suction intake 39. Ther-secondary l relatively low fuel ow rates Yin the low speed range and considerably higher fuel Vflow rates inthe upperVA speed range, the fuel pump will satisfactorily fulfillV the Vfuel demands of the engine. Y

The following morespecic analysis serves, to more 2,940,394 Y Y l 1 `fullyY outline the performance characteristics of the fuel pump for varying operationofsthe turbojet'engine 10.

The turbojet engine 10for example, may have the following representativefuelr pressure and fuel consumption requirements, as shown in the .chart 'in Fig. 4. Y

Y in', the upper. speed .range,. betweenidling andrated' speed, the fuel requiremcnts'fofatheengnieareillustratecf .by thecurveA.

,electricalcontrol Ysystemincluding a suitable'syvitch 46 the Velectrical system in series withrva suitable source Vof Y EME. 47and thesolenoid valves 41 andr42rare connected in'parallel. Also, ifrdesired, armanual'ly operable-switch Y sa may be provided for conditioning vthe systeni'for automatic operation-when desired. The speed responsive switch 46 isarranged ina mannerto. interrupt the circuit.

through the solenoid valves 41 and V42st impeller shaft thelcircuit upon` attainment of the selected, speed by the shaft. Hence, when the engineglOis operating at a speed `speeds below a preselected'speed 'valve andto complete i below the selected -value (low speedrange); the fuel Y pump isconditiorned as illustrated in Fig. 1, Whereas above l said selected value (upper Vspeed range)'the' solenoid valves 41 and 42V are energized and' their, valve meni-V bers 43 Vand 44, respectively, are moved to the unblocking l position as illustrated in Fig. 2; l Y

When'the fuel pumpis conditioned'as Ishown kin Fig. 2, fuel from the fuel supplyis directedV through -thesupply conduit 33 to lthe fuel pump through tthe primary suction inletand 'by the conduit 4t)Y through the secondary inlet 39. Hence, the fuel admitted to the fuel pump'through the primary suction inlet 31 isY translatedV throughgthe pressure developing chamber 28 inV an arcuateV path of about 90 degrees rand is then ejected from the chamber through the secondary suctionV outlet 37. This fluid stream Y is .then directed through ythel bypassApassagewayY 36 to the'fuel delivery conduit'. 23.

Accordingly, in therlo-w speed rangefor the.turbojet engine, withtthe speed responsive-switch 46 in the circuit interrupting positionaudr the manual switch 4S inV either the open or closed position, the fuelis fed to the in a like manner, the fuel admitted to the chamber 28 through the secondary suction.

rfuel ilow rate.

BY ful'her referenceftothefchartashnwn; invFig.. 4, curve. B ilustrates the low speed rangeefuel pumping. characteristicsv of the lfuel pump, withthe: solenoidxvalves 412 and 42 in theowblokngposition.. Curve-B risesrather sharply and at .about ri400, rpm.; the 'pjumpdischarge pressure is about 'p.s.i. While'atabout-,SOOO r.p.m. thepres-V sureis about 675 p.s,i. Since-the l400'r.'-p.m. coincides with the starting r.p.m. of the engine, itf will be vnoted that' the pump discharge is Vadequate to satisfy the engine fuel .pressure requirements in thisr range; However, at 5.000 r.p.rn., coinciding with theengineidlingspeedrthe pump pressure is considerably, abovethatrequired bythe engine. A'

Curve C' illustrates the... upper speed. rangefuel `pumping characteristics voi" tliefueLpumgWiththe valvesin the unblocking position.. It willfbeseen thatvvhenithe speed responsivefsvvitoh.46'encrgizesthetvalves41 and'42. to theunblockillg position, as'` indicated Aby vertical. dotted line D, the .pressurer value dropsgto, about 100 p.s.i. but

the fuel flow rate of`770'ppzh. is. maintained'.y during suchv change Vin conditioning of tlie'pump. .Thereaften as the rpm. of the impeller increases, the fuel pressure againr4 rises ina gradual manner with concomitantrincreasefin Y By comparing-curves B land-Cwith theengine'requirements mentioned above and curve"A,'i`treadily be seen that the Vfuelfpurnp iscapable offsatisfying the engine fuel requirementsinthe lovv as vvelljasrtheupper speed range. Also, in theupperspeed range, the fuelpressure` at the .pump outlet is maintained at reasonable; yetA not excessively high, values above thed engine requirements.

It will now be seen that'thefinv'ention providesa'highly i improved and versatile pumpoftleturbineitypevwhichl` may be reliably' employedas@ the mainY fuel. pump 'of-1 a fnei combustion engine, such as aturbojetfengine. l

lt will further be4 scena-'that'.theeinventgionfprovides a turbine -type fluid pump having.` dualV liowV and pressure? output characteristics'fwhich lends itself *to applicationsV engine after traversing theV fuel pump chamber 2 8 in one Y single path of large angular extent, so that although the fuelztlow rateY is moderate, the fuel pressureis relativelyV high. p

in the upper speed range; wherein thespeederesponsive Vswitch 46 is in the circuit making position, with` thev manual switch l48 inthe closed position, the fuel is de-.

livered to the engine aftertraversing the fuel pump charnber in two separate streams through angulargpaths of individually less,V extent than theV first Vmentioned. path.

Hence, the'fu'elflow .rate fis'considerably higher vvhileY the'fuel pressure value is reduced in proportion.

Since, as Well knovvnfin the -art,th e engine; 191dernandsj f extending blades, housing structure surrounding .saidim-- wherein-it is driven; atvariable: speedthrough a relatively wide range of speed-sf While vthe invention ehasibeerr shown'ixn butione form,

it will be obvious tothosefskilled vin'theuartthat it notv so limited,Y but is susceptible,.of;various;.changes and'.

modic'a-tions without,Y departingfrmnif the; spirit thereof.Y

`What is claimedfis: f Y l. ln combination, apump comprising .an impellersofY the turbine type having aci-rcumferential -roweofradiallypellerand jointly Ytherewith deningan annular uidpres# Ysurizing chamber, saidY housing structure-defining a first suction inlet; and `a first discharge ouden', asecondl suction:

inlet and a seconddischargeoutlet; said inlets'and out- Vlets communicating directlywith. said chamber, means forv diiving said impellerviny onefidiljection at varyingspeeds.

of rotation, said first inlet and outlet being angularly displaced in the direction of rotation to a greater degree than said second outlet and inlet, valve structure for blocking and unblocking said second inlet and outlet, and means responsive to speed of rotation of said impeller for controlling said valve structure, said speed responsive means being effective to maintain said valve structure in the blocking position below a predetermined speed and to move said valve structure to the unblocking position above said predetermined speed.

2. In combination, a pump comprising an impeller of the turbine type having a circumferential row of radially extending blades, housing structure surrounding said impeller and jointly therewith dening an annular iluid pressurizing chamber, said housing structure delining a first suction inlet and a first discharge outlet, a second suction inlet and a second discharge outlet; said inlets and outlets communicating directly with said chamber, means for rotating said impeller in one direction at varying speeds, said first yinlet and outlet being angularly displaced in the direction of rotation to a greater degree than said second outlet and inlet, valve structure for blocking and unblocking said second inlet and outlet, and means responsive to speed of rotation of said impeller for controlling said valve structure, said valve structure being biased in a direction to block said second inlet and outlet, and said speed responsive means being eiective to move the valve structure to an unblocking position in response to a predetermined speed.

3. ln combination, a uid pump comprising an impeller of the turbine type having a circ xferential row of radially extending blades, means for driving said impeller in one direction at varying speeds of rotation including a low speed range and a high speed range, housing structure surrounding said impeller, said housing structure and said impeller jointly defining an annular fluid pressurizing chamber, said housing structure further dening a rst suction inlet, a rst discharge outlet, a second suction inlet and a second discharge outlet, all of said inlets and outlets directly communicating with said chamber; said iirst inlet and outlet being angularly displaced in the direction of rotation of said irnpeller to a greater degree than said second outlet and inlet, said second outlet being disposed upstream of said second inlet relative to fluid ilow through said chamber, valve structure for blocking and unblocking said second inlet and outlet, said valve structure blocking said second inlet and outlet said low speed range, and means responsive to speed of rotation of said irnpeller for jointly controlling said valve structure, said speed responsive means being eective to move said valve structure in unblocking ldirection in response to a predetermined speed, in said high speed range.

4. In combination, a fluid pump comprising an impeller of the turbine type having a circumferential row of radially extending blades, a housing enclosing said impeller and jointly therewith defining an annular iluid pressurizing chamber, said housing having a main suction inlet and a main discharge outlet, said yhousing further including wall structure dening an arcuate flow passage disposed externally of said impeller and communicating with said main discharge outlet, means deining a secondary suction inlet communicating with said impeller intermediate said main inlet and outlet, said housing providing a secondary discharge outlet communicating with said ow passage, electrically actuated valve structure for blocking and unblocking said secondary inlet and outlet, means for driving said impeller at varying rates of rotational speed, and

means including a switch responsive to speed of Said driving means for jointly controlling said Valve structure, said switch means being operative to eect movement of said valve structure from the blocking position to the unblocking position above a predetermined speed, thereby to increase the fluid ilow rate and decrease the iluid pressure at said main discharge outlet.

5. In combination, a iluid pump comprising an impeller of the turbine type having a circumferential row of radially extending blades, a housing enclosing said impeller and jointly therewith deiining an annular uid pressurizing chamber, said housing further defining a main suction inlet and a main discharge outlet communicating directly with said chamber, wall structure defining an arcuate ow passage disposed in bypass relation with said chamber and communicating with said main discharge outlet, means deining a secondary suction inlet communicating directly with said chamber intermediate said main inlet and outlet, means defining a secondary discharge outlet connecting said chamber and said flow passage, said secondary outlet being disposed intermediate said primary and secondary inlets, electrically actuated valve structure for blocking and unblocking said secondary inlet and outlet, means for driving said impeller at varying rates of rotational speed, and means including a switch responsive to speed of said driving means for jointly controlling said valve structure, said switch means being operative to eect movement of said valve structure from the blocking position to the unblocking position above a .predetermined speed, thereby to increase the `fluid ow rate and decrease the fluid pressure characteristics of the pump.

6. ln combination, a iluid pump comprising an impeller of the turbine type having a circumferential row of radially extending blades, a housing enclosing said Iimpeller and jointly therewith dening an annular fluid pressurizing chamber, said housing having a main suction inlet and a main discharge outlet, said housing further including wall structure defining an arcuate ow passage disposed externally of said impeller and communicating with said main discharge outlet, means defining a secondary suction inlet communicating directly with said irnpeller intermediate said main inlet and outlet, said housing providing a secondary discharge outlet communicatving with said ovv passage, electrically actuated valve structure for controlling fluid ow through said secondary inlet and outlet, means for biasing said valve structure to the position blocking said secondary inlet and outlet, means for driving said -impeller at varying rates of rotational speed, and means .including a switch responsive to speed of said driving means for jointly controlling said valve structure, said switch means being operative to effect movement of said valve structure from the position blocking said secondary .inlet and outlet to the position unblocking said secondary inlet and outlet at a predetermined speed and to maintain said valve structure in the unblocking position at speeds above said predetermined speed, thereby to increase the fluid flow rate and decrease the duid pressure at said main discharge outlet.

References Cited in the le of this patent UNITED STATES PATENTS wright July s, s

UNITED STATES PATENT OFFTCE @ERTIFICATE 0F CRBECTIUN Patent No 2 2&194O394 June 14V 1960 Garrett Eo Mesure t is hereby certified that error appears in the printed specification o the above numbered patent requiring correction and that the said Letters Paten-t should read as corrected below;

Column 5l line 47g after E'outletm insert we in we Signed and sealed t'he 25th dey of April lQL (SEAL) Attest:

ERNEST Eu SWTDEE DAVID Le LADD ttesting Ocer I Commissioner of Patents

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