US2196500A - Fuel pump - Google Patents

Description

9., I .L P JOHNSON l l FUEL PUMP f original Filednaron 12, 19:55

' 4Z J'Anss R JOHNSON ATTO RN EY 'objects hereinafter explained in view, the in- Patented Apr. 9, 1940 'UNITED ,STATES FUEL PUMP James P. Johnson, Shaker Heights, Ohio, assignor, by mesne assignments, to Pump Engineering Service Corporation, Cleveland, Ohio, a corporation of Ohio Application March 12, 1935, serialNo. 10,644r Renewed November 10, 1938 15 Claims..

' object to provide an improved fuel pump which is simple and compact in construction, eiiicient and dependable in operation, and relatively inexpensive to manufacture.

A further object of the invention is to provide relief means for the excess of fuel delivered by the pump over the amount capable of being handled by the carburetor and adjustable so asv to vary the pressure at which the fuel isdischarged from the pump. l

A still further object of the inventionlis to provide means by which the fuel may be bypassed from the inlet vside to the'outlet side of the pump and. subsequently to the carburetor in the event the pump should become incapacitated.

It is well known that changes in flying conditions, such as different altitudes, banking, rising, diving, etc., result in pressure changes particularly with respect to the fuel supply which causes the fuelto be supplied to the pump at varying pressures. i This condition vis undesirable because the fuel delivered from the pump tothe carburetor is likewise delivered at varying pressures whereas the most' efilcient operation demands that the fuel be delivered at a constant pressure. It is, therefore, a further object to provide a balancing means for the excess fuel relief means which is unaffected by changes in flying conditions so thatl the fuel is delivered constantly at the desired pressure.

Another object of the invention resides in providing a pump which may be operated in either direction without requiring any changes or ad-- ,justinent in the'operating parts and with the by-pass and relief valve arranged as a unit so as to require adjustment only by reversing-the position thereof to correspond with the direction of rotation ofthe rotory of the pump. Y,

With the f objects above indicated 'and other ven'tion consists in the construction and combination of elements hereinafter described land claimed.

Figure 3 is a longitudinal sectional view taken. on line 3 3 in Figure 4; I

Figure 4 is an end elevational view, partly in section, taken on line 4 4 in Figure 3. o In the drawing va fuel pump embodying the present invention is illustrated and for sake of clarity a brief explanation of its use in connection with aircraft will be set forth. In connecting the fuel pump for operation the outlet opening of the pump is connected with the inlet side of the carburetor for supplying fuel to the motor. The carburetor is designed to, handle a varying volume of fuel at a definite pressure for the most eilicientA operation of the motor. It has been found that the pressure of the fuel should be maintained at approximately 3% pounds under all flying conditions and heretofore this has not been possible. The failure to deliver the fuel to the carburetor at a 4constant pressure has been due to the fact that the pressure of the fuel delivered to the pump from the storage tanks varies materially by reason of changes in altitude, banking, diving, rising and other causes. With the improved fuel'pump this disadvantage is eliminated and not only is the fuel delivered at a constant pressure but this pressure may be varied at will to adapt the pump to dierent conditions. y

The fuel pump is indicated generally byv the numeral I and consists of a housing II, prefthreaded opening Il on one side thereof which extends inwardly intor communication with the axial bore I2 while the opposite side of'the housing is provided with a similar ,interioriy screw-threaded opening I5 extending inwardly and likewise communicating with the bore I2, as more clearly shown in Figure 4. These openings It and I5 are adapted to be connected one with the fuel supply andthe other with the carburetor which supplies the fuel to the Imotor, and the respective openings will be connected in the manner herein stated, depending upon the direction of operation of the fuel pump in'a manner hereafter more specifically described.

A spacer member I6 ,is positioned within the axial bore I2 and abuts the end wall Il of the ,o housing' and positioned ahead o f'th'e spacer-.mem- 4 lber is a linerV Il preferably of hardenedsteel l`and `which p xfovideii with fl A rotor 2|, preferably of hardened steel, is

eccentrically positioned Within the chamber I8 and has a running engagement .with the inner peripheral wall of the chamberat 22 which sep- "arates the opening I9' from the opening I3.

The body 'of the rotor extends between the spacer members IE and 20, as vshown in Figure 3, and is provided with axial extensions 23 formed integral upon the -oppositeends thereof which are rotatably mounted in the spacer members I6 and 20.

The body portion of the rotor 2| is provided with angularly disposed slots extending longitudinally thereof and Within which are slidably mounted a plurality of blades 24, the blades being coextensive with the space between the adjacent inner surfaces of the spa/cer members i6 and 20. The outer ends of the blades 24 are adapted for engagement with the inner peripheral Wall of the chamber I8, While the inner ends of the blades extend inwardly within an axial bore 25 provided in the rotor and extensions 23. A roller member 26 is freely positioned within the bore 25 and is adapted for engagement with the inner ends of the blades 24 to maintain the latter'in spaced relation.

The outer open end of the housing is interiorly screW-threadedto receive an exteriorly screw-threaded plug 21 having a laterally extending fiange 28 adapted to abut with the adjacent end of the spacer member 20 and to maintain the spacer members and liner |1 in assembled relation. An attaching plate 23 is mounted on the outerend of the housing and secured in place by a plurality of screws 30 which engage screw-threaded openings in a circumferential flange 3|' formed integral with the outer surface of the housing as more clearly shown in Figure 3.- The outer end of the plug 21 is provided with angularly arranged slots 21a so that the plug 21 may be locked in any desired adjusted position and is maintained in locked condition by means of a plate 32 fitting within one 0L the slots 21a (and an aligned slot in the adjacent end of the'housing being removably secured in place by means of a screw 33.

It is desirable to provide a flexible or yieldable coupling between the driving means and the rotor, and in the present instancel this is accomplished by providing a drivenA member 34 mounted within the flange 28 of the plug 21 and having a laterallyextending flange 35 which abuts the adjacent surface of the spacer member 20.. This member is also provided with a transverse projection 36 which fits within-transversely aligned recesses provided in theouter end of the extension- 23, as more clearly showny in Figure 3.

A drive member 31 is in axial alignment with the driven member 34 and has a laterally extending ange 38. the outer portion of which abuts a ring 39 secured to the inner side of the plug 21. A coiled spring 40 surrounds the members 34 and 31 and has its opposite ends abutting the - adjacent flanges 35 and 38 to maintain the members in spaced relation. The adjacent ends Y operate in different directions.

. 2,190,500. Aeccentric with the axis of the borev I2. This of the members 34 and 31 have interengaging formations providing a positive driving connection and of such construction as to provide full oating of the driving member 31. An axial extension 4| is provided 'upon the outer side of the driving member 31A which projects through an l oening in the pmg 21 and which is adapted for connection with the motor or other driving means.

Screw-threaded openings are provided in the housing which are normally closed by removable screw-threaded plugs 42 and provide means by which a suitable lubricant may be supplied to the movable parts of the pump. A pini 43 secured in the housing has its inner end disposed in a longitudinally extending slot |44 provided in the liner |1 to prevent'relative angular movement with respect to the housing.

The operating parts of the pump are, of course,

so arranged that the pump may be operated in either direction without the necessity of rearrangement, which is quite advantageous in view of the fact that diilerent types of motors Itis not necessary, therefore, to change the position of the pump irrespective of the direction of rotation of the motor.

When the pump is used on an airplane the rotor is operated at various speeds, depending upon the R. P. M. of the motor, as the rotor is4 usually connected to the motor to operate at the same or slightly greater R. P. M.A The volume of fuel'pumped by the pump therefore varies with the changes in the R.. P. M., and at 2000 R. P. M. approximately 350 gallons of fuel per hour is pumped by the pump. Such a volume of fuel is, of course, out of proportion to the volume of fuel adapted to be'handled by the carburetor, and means must therefore be provided to return the excess fuel to the inlet side of the pump. Furthermore, for efficient operation of the motor, the fuel should be delivered at a constant pressure irrespective of the volume required and the pressure most effective has been found to be approximately 31/2 pounds, although this may vary somewhat, depending upon different conditions. pump to maintain the volume of fuel discharged at a constant pressure and irrespective of iiying conditions.

1 -The preferred arrangement consists of a second housing 43 having a circular wall 44 andremovably connected to the top of the first housing ||by a 'plurality of bolts 45. The housing 43 has a transverse partition 46 adjacent its lower end provided with a transverse axial opening forming a valve seat 41 and a second transverse opening 48 in alignment with a transverse opening 49 provided in the housing adjacent the fuel inlet opening I4 when the rotorV operates in the direction of the arrow shown in Figure 4 to provide a fuel passageway in communication with the upper side of the valveseat 41. The lower end of the housing 43 has an opening 50 in alignment with an opening 5| provided in the housingadjacent the fuel outlet opening I3 and providesA a passageway for the fuel on the under side of the valve seat 41. ,Y

A valve member 52 is adapted to engage the valve seat 41 and has a depending extension 53 slidably mounted in an opening provided in the housing 'I'he housing Il may also have a flange 54 which extends into an opening in the housing 43 and centers one with respect to the other. The extension 53 of the valve member is Means are, therefore, provided in the.

mounted so as to have a dash pot operation for apurpose to be later described. The valve member 52 therefore controls the flow of excess fuel from the outlet openingv I5 to the inlet opening I4 permitting a recirculation of the fuel in excess of that capable of being handled by the carburetor.

The valve member 52 is yieldably resisted in its movement by a spring 55 of the desired size, which spring is disposed in a vsleeve 55 closed at its lower end and provided with an extension 51 which loosely engages" the adjacent end of the valve member 52 as clearly shown in Figure 3. The sleeve 56 is slidably mounted in an opening provided in a 4cover plate v58 removably connected to the upper open end of the housing 45 by a plurality of bolts 59. The cover plate 55 has an axial hollow extension 50, exteriorly screwber 65 any desired compression threaded to receive a locking nut 5I. A member 52 which is exteriorly screw-threaded at its upper end has an enlarged portionl slidably mounted in the upper end of -the sleevev and engageable with the upper end of the spring 55. The sleeve 55 is longitudinally slotted at its upper portion to receive a projection 'formed on the lower end of the enlarged portion .53 to-v prevent relative angular movementl therebetween. A manually operated member hasjan axial interiorly screw-threaded opening which cooperates with the screw-threaded portion ofthe member 52 and by turning the same in one direction or the other about the axis the pressure/of the spring 55 may be varied. 'A circumferential flange 55 is formed on the member 55 and is adapted to be secured between the nut 5I and the endof the extension 5I! so as to clamp the member in the desired adjusted position; With thisv arrangement a very fine adjustment of the spring is made possible as there is no tendency for the spring to wind or unwind while it i's being compressed or released. Thus by adjusting the memmaybe obtained in the spring 55, thereby exerting the proper pressure onthe valve member 52, say 31/2 pounds,

or the pressure at which fuel is delivered to the carburetor.

` To assure that the fuel will be delivered at the pressure at which the valve 52 is s 'et irrespective of flying conditions which tend to produce varying pressures at the inlet opening I4, a balancing.y

means is provided which consists in the present instance of an expansible and contractible bellows 51 encircling the sleeve 55 and having its lower end sealed to the lower end of the sleeve.` The Vupper end of the bellows 51 is secured to the cover plate 58 and the effective outside area of the'bellows is equivalent to the effective area of the uibper surface of valve 52 subject to the suction of the pump created at the inlet opening 14., The inside of the bellows 61 is in communication with the atmosphere by means of'an opening/inv the member 52 and a small hole 55, approximately #80 drill, provided'in the 'member 55, thishole beingl so small as to prevent 'any great loss of v vacuum, in the event 'the bellows should break,

but which would not prevent proper operation of the pump. The dash pot mounting ofthe valve member.52 also tends to prevent impulses from the four-blade driven rotor fromloscillating the bellows which might otherwise cause fatigue.

In the event the pumping means should become inoperative for any reason, a fuel b y-pass is provided by which fuel may vbe supplied to the carburetor. In the present instancajthe transverse partition u is preview-with a plurality ofv transverse openings 69, six of which are shown although not restricted thereto, angularly spaced as shown in Figure 1.v A plurality of ball valves 'I0 engage the under side of the openings 69 and normally close the latter to prevent the passage of fuel therethrough. Springs 1I are housed in sleeves'12 vsecuredvt the housing 43 and have one end engaging .the ball valves to yieldingly hold them in closed position. The inlet opening I4., may be connected with a hand pump on the ln` strument board and by operating the latter fuel will be forced into the inlet opening I4 and will pass upwardly through the openings and 45 to the upper side of the partition 45. The pressure of the fuel will unseat the ball valves 10 and permit the fuel to pass through into the openings [the arrow.' The housing 43 is suitably marked intake on one end so that that endv will be positioned adjacent the fuelinlet opening of the pump. The end ofthe pump housing I I may also be marked as shown in Figure 2 to indicate the outletf depending upon the direction of rotation of rotoras indicated by the arrows In the operation ofthe pump with the parts in 4the relation shown in the drawing, the rotor creates a suction or vacuum at the inlet opening I4 drawing the fuel from the tanks andforcing it through the outlet opening I5 to the carburetor at a definite pressure, the valve member 52 having been rst set for that pressure. The carburetor, of course, can only handle a relatively small volume of fuel compared with that handled. by thepump andthe excess of fuel therefore vpasses upwardly through the openings 5I' and 50 and unseats the valve member 52 passing downwardly through the openings 45 and 49 to the inlet opening I4 'also aided by the suction at this point.

me to the fact that the bellows s1 is subjected to the vacuum or suction at the inlet opening produced by the rotor and beingvin communication with the atmosphere upon the opposite side, the' ing'pressures in the fuel line to the inlet opening i have no effect upon the pressure exerted on the valve member 52.

While I have described the preferred embodiment of the inventionlt should beunderstood that I am not to be limited thereto inasmuch as changes and `modifications m'ay be resorted to without departing from the spirit of the invention as defined in the appended claims.

What is claimed is:

1 A fuel pump comprising a housing pro- `vided with fuel inlet and outlet openings, pumping means in said housing for delivering the fuel from 'said' inlet opening tosaid outlet opening, said housing having an excess fuel return passageway communicating with said inlet and outlet o'penings, a movable valve member mounted irl-"said-hou'sing and operatively associated with said fuel return passageway for controlling the flow of excess fuel therethrough, a sleeve mounted in said housing and having its inner end closed andfreely engageable `with saidivalve member, a

l-lows surrounding said sleeve Vand having its lower end in sealing engagement therewith,` the upper end of said bellows being connected to said housing, a coiled spring disposed within said sleeve and having one end engaging the closed end of said sleeve, van axially movable member disposed in said sleeve and having its inner end engageable with the other end of said spring and its outer end exteriorly screw-threaded, said member having an opening extending longitudinally therethrough in communication at one end with the interior of said bellows, cooperatingmeans on said sleeve and axially movable member to prevent independent relative movement about the axis thereof but permitting free relative movement axially, an internally screwthreaded cap mounted on the end of said axially movable member for moving the same to vary the tension of said spring and having a lateral extension engageable with said housing, said cap having an-opening extending therethrough in communication with the opening in said axially movable member, and a clamping nut removably mounted on said housing and having a portion engageable with said lateral extension to secure lthe latter in adjusted position.

2. A fuel pump comprising a housing proper provided with fuel inlet and outlet openings on opposite sides thereof, said housing being further provided with a transverse opening adjacent the inlet opening and a similar transverse opening adjacent the outletopening, pumping means in said housing vfor delivering the fuel from said inlet opening to said outlet opening, a projection on the outside of said housinglocated between said inlet and outlet openings and having an axial opening therein, a tubular shaped housing detachabl-y connected to the outside of said housing proper 'concentrically with respect to said projection, a transversely extending partition formed integral with said tubular shaped housing and having an axial opening therethrough to provide a valve seat on the outer side of said partition concentric with respect to the opening in said projection, a valve member having a portion engageable with the valve seat and an axial extension projecting through the opening in said partition and slidably disposed within theLV opening in said projection, the end of said extension terminating short of the bottom of said opening to provide a dash pot, the under side of said valve being in communication with the transverse opening in said housing proper adjacent the outlet opening and the top side being in communication with the transverse opening adjacent the inlet opening said valve member being adapted to control the flow of fuel thereby, a cap detachably connected to the outer end of said tubular housing, a coiled spring disposed within said tubular housing and having one end engageable with said valve member for normally urging the latter into engagement with said valve seat, and an axially movable member having its innerend engageable with the outer end of said spring and adjustably connected to said cap for varying the tension .in said spring.

3. A fuel pump comprising a housing proper provided with fuel inlet and outlet openings on opposite sides thereof, said housing being further provided with a transverse opening adjacent the inlet Aopening and a similar-transverse r'opening adjacent the outletopening, pumping means in said `'housing'for delivering the fuel from said inlet opening to said-outlet opening, a projection on the outside of said housing locatedbetween said inlet and outlet openings and,hav ing an axial opening therein, a tubular shaped housing detaohably connected to the outside of Y said housing proper ,concentrically with respect to said projection, a transversely extending partition formed integral with said tubular shaped 'housing and having .an axial opening therethrough to provide a valve seat-on the outer side of said partition concentric with respect to the opening in said projection, a valve member hav- 4ing a portion engageable with the valve'seat and an axial extension projecting through the openin'g. in said partition and slidably disposed within the opening in said projection, the end ofrsaid extension terminating short of the bottom of said opening to provide a dash pot, the under side of said valve being in communication with the transverse opening in said housing proper adjacent the outlet opening and the top side being in communication with the transverse opening adjacent the inlet opening, said valve member being adapted to control the iiow of fuel thereby,

a cap detachably connected to the outer end of said tubular housing, a sleeve mounted in said tubular housing and having its inner end closed and engageable' with said valve member, a coiled spring disposed within said sleeve and having one end engaging the closed end thereof for normally urging the latter into engagement with said valve member, and an axially movablemember having its inner end engageable with the outer end of said spring and adjustably connected to said cap for varying the tension in said spring.

4. A fuel pump comprising a housing proper provided with fuel inlet and outlet openings on opposite sides thereof, said housing being further provided with a transverse opening adjacent the inlet \opening and a similar transverse opening adjacent the outlet opening, pumping means in said housing for delivering the fu'el fromI said inlet opening to said outlet opening, a projection on the outside of said housing located between said inlet and outlet openings and having an axial opening therein, a tubular shaped housing detachably connected to the outside of said hous- .ing proper concentrically with respect to said 'provide a valve seat on the outer side of said partition concentric with respect tothe opening in said projection, a valve member having a porvtion engageable'with the valve seat and an axial extension projecting through the opening in said partition and slidably disposed within the opening in said projection, the end of said extension terminating short of the bottom of said opening to provide a dash pot, the under side of said valve being in communication with the transverse opening in said housing proper adjacent the outlet opening and the top side being in communication with the transverse opening adjacent the inlet opening, said valve member being adapted to control the flow 4of fuel thereby, a cap detachably connected to the outer end of said tubular housing, a sleeve mounted in said tubular housing and having its inner end closed and ensaid spring and adjustably connected to said cap for varying the tensionin'said spring.

5. A fuel pump comprising a housing proper provided with fuel inlet and outlet openings on opposite sides thereof, said housing being further provided with a transverse opening adjacent the inlet opening and a similar transverse opening ladjacent the outlet opening, said housing for delivering the fuel from said inlet opening to said outlet opening, Ya projection on the outside of said housing located between said inlet and outlet openings and having an axial opening therein, a tubular shaped housing detachably connected to the outside of said housing .properv concentrically with respect to said projection, a transversely extending partition formed integral with saidy tubular shaped housingand having an axial opening therethrough to provide a valve seat on the outer side of said partition concentric with respect tov the opening in said projection, a valve member having a portion engageable with the valve seat and an axial extension projecting through the opening in said partition and slidably disposed within the opening in said projection, the end of said extension terminating short of the bottom of said opening to provide a dash pot, the under side of said valve being in communication with the transverse opening in said housing proper adjacent the out-`l let opening and the top side being in communication with the transversevopening adjacent the inlet opening, said valve member being adapted to control the ow of fuel thereby, a cap detachably connected to the outer end ofsaid tubular housing, a sleeve mounted in said tubular housing and having its inner end closed and engageable with said valve member, a bellows surrounding said sleeve and having its lower end in sealing engagement therewith, the upper end of said bellows being Vconnected between said cap and the adjacent end of said tubular housing, a coiled spring disposed within said sleeve and having one end engaging the closed end thereof for normaly urging the latter into engagement with said valve member, an axially movable member having its inner end engageable with the outer end of said spring and adjustably conneced to said cap for varying the tension in said spring,

said partition having a plurality of openings on diametrically opposite sides of said valve member providing valve seats upon theunder side of said partition, individual ball valve members adapted for cooperating engagement with said valve seats, coiled springs having one end engaging said ball valve members for normally urging the latter against said valve seats, and sleeves to receive said coiled springs and having portions against which the opposite ends of said springs abut, said sleeves being secured in said tubularfhousing, said ball valve members permitting the flow of fuelfrom the inlet opening to said outlet opening driven,

independently of said pumping means.

6. A'rotary fuel pump for use on aircraftcomprising .a housing proper provided with fuel inlet and outlet openings adapted for connection with the fuel tank and carburetor respectively, rotary pumping means in said housing proper for delivering fuel from said inlet opening to said outlet opening and adaptedffor rotation in either direction, said pumping means having -a portion projecting outwardly beyond said housing proper by which said pumping means is vadapted to be a. second hollow housing extending laterally of said housing proper and detachably connected to the latter, cooperating means on pumping means inl 'said housings -for definitely positioning one with respect to the other, said second housing being provided with a partition extending transversely thereof, said partition having an axial opening therethrough providing a valve seat on its outer \side, a movable valve member having a valve head engageable with said valve seat and an axial projection piloted'- in an' opening provided in said housing proper and adapted to control the flow of excess fuel from said fuel outlet opening to said fuel inlet opening,

the opposite sides of said valve head being in communication with said fuel inlety and outlet openings respectively through openings provided in said housing proper adjacent the respective fuel inlet and outlet openings, resilient means mounted in said second housing and engageable with said valve head for normally main- 'taining the latter in engagement with its valve seat, said partition being further provided with openings extending transversely therethrough providing valve seats on the under side of said partition and adapted to by-pass fuel from said inlet opening to said outlet opening through the openings provided in said housing proper adjacent the respective fuel inlet and outlet openings independently of said pumping means, and valve members resiiiently mounted in said second housing and normally engageable with said valve seats, said second hollow housing being removable as a unit and having two positions of mounting on said housing propen'depending upon the direction of rotation of said pumping means, the inner side of said valve head munication with the fuel outlet opening through one or the other of said openings provided in said housing proper adjacent the respective fuel inlet and outlet openings.

7; A rotary fuel pump for use on aircraft comprising a housing proper provided with fuel inlet and outlet openings adapted for connection with the fuel tank and carburetor respectively, rotary pumping means in said housing proper for delivering fuel from said inlet opening to said outlet opening and adapted for rotation in either direction, said pumping means having a portion pro'- jecting outwardly bevond said housing proper by which said pumping means is adapted to be driven, a second hollow housing extending laterally of said housing proper and detachably connected to the latter, cooperating means on saidhousings for definitely positioning one with respect to the other, said second housing being provided with a partition extending transversely thereof, said partition having an axial opening therethrough providing a valve seat on its outer side, a inovable valve member having a valve head engageable with'lsaid vvalve seat and an axial projection piloted in an opening provided in said housing proper and adapted to control the flow of excess fuel from said fuel outlet opening to said fuel inlet opening, the opposite' sides of said valve head being in communication with said fuel inlet and outlet openings respectively through openings provided in saidhousing proper adjacent the respective fuel inlet and outlet openings, resilient always being in commeans mounted in said second housing and en,

independently of said pumping means, individual ball valve members normally engageable with the valve seats on the under side of said partition, and coiled springs having one end engaging said ball valve members and their opposite ends secured in said second housing, said second hollowl housing being removable as a unit and having two positions of mounting on said housing proper, depending upon the direction of rotation of said pumping means, the inner side of said valve head always being in communication with the fuel outlet opening through one or the other of said openings provided ln said housing proper adjacent the respective fuel inlet and outlet openings.

8. A rotary fuel pump for use on aircraft comprising a housing proper provided with fuel inletv and outlet openings adapted for connection with the fuel tank and carburetor respectively, rotary pumping means in said housing proper for delivering the fuel from said inlet opening to said outlet opening yand adapted for rotation in either direction, said pumping means having a portion projecting outwardly beyond the housing proper by which said pumping means is adapted to be driven, a second hollow housing extending laterally of said housing proper and detachably connected to the latter, cooperating ineans on said housings for definitely positioning one withv respect to the other, said second housing being provided with a partition extending transversely thereof, said partition having an axial opening therethrough providing a valve seat on itsv outer spective fuel inlet and outlet openings, resilient means mounted in said second housing and having one end freely engageable with the adjacent side of said valve head for normally maintaining the latter in engagement with its valve seat,

means operatively connected with said resilient means and adjustably mounted in said second housing for varying the pressure exerted upon said valve head, and an expansible and contractible sylphon disposed concentrically with respect to said resilient means and having its inner end in sealing engagement with the-latter, the outer end being open and having its marginal edgeconnected to said second housing, the interior of said sylphon being vented to atmosphere by means of a small opening substantially ineffective to cause loss of vacuum in theevent said sylphon should become broken and effective to balance said resilient means, said -second hollow housing being removable as aunt and having two positions of mounting 'on said housing proper, depending upon the direction of operation of said pumping means, the inner side of said valve head always being in communication. with the fuel outlet opening through one or the other of the openings provided in said housing proper adjacent the respective fuel inlet and outlet openings.

9. Afuel pump comprising a housing proper provided with fuel inlet and outlet openings, said pumping means in said housing for deliveringv portion of said housing proper, the end of saidl extension terminatingshort of the bottom of said opening to provide a dash pot, the under side of said valve. being in communication with the transverse opening in said housing proper adjacent the'outlet opening and the top side being in communication with the transverse opening adjacent the inlet opening, said valve member being adapted to control the flow of fuel thereby, means engageable with said valve member and adjustably connected to said tubular housing for yieldable urging said valve member into engagement with its valve seat, said partition havinga plurality of openings onI diametrically opposite sides of. said valve member and providing valve seats upon the under side of said partition, individual ball valve members adapted for cooperating engagement with said valve seats, coiled springs having one of their'ends secured to saidlli tubular housing and their other ends engaging said ball valve members for normally urging the latter against said valve seats, said ball valve members permitting the flow of fuel from the inlet opening to the outlet opening independently of said pumping means.

10. A fuel pump'comprising a housing proper provided with fuel inlet and outlet openings, said housing being further provided with a transverse opening adjacent the inlet opening and a similar transverse opening adjacent the outlet lopening, pumping means in said housing for delivering the fuel from said inletopening to said outlet opening, a tubular shaped housing detachably connected to the outside of said housing proper, a transversely extending partition within said tubular shaped housing and having an `axial opening therethrough to provide a valve seat on the outer side of said partition, a valve member having avalve head engageable with the valve seat and an axial extension projecting through the opening in said partition and slidably disposed within an opening provided inthe adjacent portion of said housing proper, the end of said extension terminating short of the bottom of said opening to provide a dash pot, the

under side of said valve being in communication with the transverse opening in said housing proper adjacent the outlet opening and the top side being in communication with the transverse opening adjacent the inlet opening, said valve member being adapted to control the flow of fuel thereby, a cap detachably connected to the outer end of said tubular housing., a sleeve mounted in said tubular housing and having its inner end closed and engageable with said valve member, a bellows surrounding said sleeve-'and having its lower end in sealing-engagement therewith, the upper end'fof said bellows being connectedubetween said cap and the adjacent end of saidl tubular housing, a coiled spring disposed within said sleeve and having one end'engaging the closed end thereof for normally urging the latter into engagement with said valve member,

. tion area such that the inlet suction acting thereprising a housing provided with fuel inlet and outlet openings adapted for connection with thev fuel tank and carbureter respectively, rotary pump means in said housing for delivering fuel from said inlet opening to said outlet opening,

said housing having an excess fuel return pas.

sageway connecting said outlet opening with said inlet opening, a movable' valve member mounted in said housing and operatively associated with said fuel return passageway for controlling the flow of fuel therethrough, said valve member having a valve stem slidably disposed within an opening provided in the adjacent portion of said housing to provide a dash pot for minimizing vibrations imparted to said valve membena bellows having va closed end freely engageable with said valve member and its opposite end open and secured to said housing in sealing relation, resilient means having one end in engagement with the closed end of said bellows and extending outwardly therefrom, said lmeans being adapted to maintain a constant pressure on said valve member, and means adjustably mounted on said housing and having one end operatively connected to the outer end of said resilient means whereby the resiliency of the latter may be varied, the inside of said bellows being vented to atmosphere so that said valve member is always in balanced condition therefore unanected by changes in atmospheric pressure under flying conditions.

12. A rotary fuel pump ior use on aircraft comprising a housing proper provided with fuel inlet and outlet openings adapted for connection with the fuelrtank and carbureter resctively, rotary pumping means in said housing proper for'delivering fuel from said inlet opening to said outlet opening and adapted for rotation in either direction, a second hollow housing estendinglatorally of said housing proper and detachably connected to the latter, cooperating means on said housings for definitely positioning one with respect to the other, said second housing being provided with a partition extending transversely thereof, said partition having an axial opening therethrough providing a single valve seat on its outer side, a movable valve member having Ia valve head provided with asingle valve seat engaging surface and an axial projection piloted in an opening provided in said housingA proper, said valve member beinga'dapted to control the ow of excess fuel Ifrom said outlet opening to said inlet opening, the opposite sides of said valve head being in communication with said fuel inlet and outlet openings respectiveiy /through openings provided in said housing proper adjacent the relspective fuel inlet and outlet openings, means for balancing the inlet suction e'ect on said valve irrespective of the values 'thereof due to the varying speed of said pump, said means comprising a bellows mounted in said second housing and having its inner end closed and having limited engagement with the adjacent side of said valve head about the central portion thereof only, the

. inside of said bellows being open to amosphere,

said bellows being sealably connected 'smut the periphery to the adjacent housing, said valve having an eective suction area whereby the inlet suction tends to open the same with a predetermined force for a given pump speed, said bellows being constructed with an effective sucon produces a force tending to hold said valve closed, which force is equal to said predetermined f force, whereby to balance said suction opening eifect acting on said valve, said relationship prevailing overa wide range of inlet suctions, resilient means mounted in said second housingr and having a portion engageable with the closed end of said bellows to normally maintain the latter in engagement with said valve member, and means adjustably mounted in said second housing and operatively connected to said resilient means whereby the resiliency of the latter may be varied.

13. A rotary punip for use on aircraft comprising a housing proper provided with fuel inlet and outletxopenings adapted forconection with the fuel tank and carburetor respectively, rotary pumping means in ,said housing proper for delivgering fuel from said inlet opening to said outlet opening and adapted for rotation .in either direction, a second hollow housing extending laterally of said housing proper and detachably connected to the latter, said second housing. being provided with a valve seat, a movable valve member having a valve head engageable with said valve seat and adapted to control the iow of excess fuel from said fuel outlet opening to said fuel inlet opening, the opposite sides of said valve head being in communication with said fuel inlet and outlet openings respectively, a sleeve mounted in said second housing and having. its inner end closed and engageable with the adjacent side of said valve head, a bellows surrounding said sleeve and having its lower end in sealing engagement there with, the upper end of said bellows being connected to said second housing and the inside open to atmosphere, resilient means mounted in said sleeve and having a portion engageable with the closed end thereof to normally maintain said v l valve head in engagement with said valve seat,

and means adjustahly mounted in said second housing and operatively connectedto said resilient.

meanswhereby the resiliency of the latter may be varied, said second housing being removable as a unit and having two'positions of mounting on said housing proper depending upon the direction of rotation of said pumping means.

14..In 'an aircraft fuel pump and relief valve l assembly effective to deliver a constant outlet pressure irrespective of the varying speed of the pump, said assembly comprising a housing having fuel inlet and outlet openings, means in said housing for pumping fuel from said inlet to said valve irrespective of the varying values thereof due to the varying speed of said pumprsaid means .comprising ailexible sealing means, vmeans cony nectingI said nexible sealing means about the periphery thereof to the adjacent Nhouslng, said sealing ymeans including means at the axial portion thereof for urging said valve to closed position, said iiexible sealing means being in communication on the side thereof adjacent said valve with said inlet, resilient `means acting on said urging means in valve closing direction with a predetermined force,4 the effective suction area of said sealing means responsive to inlet suction tending to close the valve being made equal to the effective suction area of said valve tending to open the same, whereby widely varyinginlet suctions do not affect the operation of said valve.

-15. In a fuel pump adapted for aircraft and including a housing having fuel inlet and fuel outlet openings, means in said housing for pump ling fuel from said inlet to said outlet, a passage in said housing leading around said pumping means therein from the outlet to the inlet of said pump, a valve seat in said passage facing generally away from said pump outlet, a valve ,arranged to be received on said seat for controlling the flow of fuel through said passage, said valve being in communication on the underside thereof with said outlet and on the other side'- thereof with said inlet, sealing means for rendering said valve unresponsive to the' effects of suction at said pump inlet in communication therewith, said means comprising4 a flexible sealmeans at said axial portion of said sealing member for urging said valve toward closed position with a predetermined force, the eiective suction area of said sealing means being made equal t'o the effective suction'area of said valve whereby the 'inlet suction effect on said sealing means' tending to close said valve balances the inlet suction effect on said valve tending to open the same, said arrangement being further particularly characterized by the provision of a second valve means communicating said pump inlet with said pump outlet around said pumping element and adapted to respond to an emergency pres- 2@ sure supply introduced into said pump inlet.

JAMES P. JOHNSON.

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