US2959004A - Pumping system - Google Patents

Description

Nov. 8, 1960 L. gElNER 2,959,004

PUMPING SYSTEM Filed March 19, 1957 INVENTOR LEONARD GREINEIR /M ZM BY 4M4 M ATTORNEYS United StatesPatent O PUMPING SYSTEM Leonard Greiner, Richmond, Va., assignor to Experiment Incorporated, Richmond, Va., a corporation of Virginia Filed Mar. 19, 1957, Ser. No. 647,086

5 Claims. (Cl. 60-39.48)

The present invention relates to a pumping system and more specifically to an automatic gas operated fuel feeding apparatus.

It is an object of the present invention to provide a unique and highly useful pumping system which eliminates many of the inherent disadvantages of prior systems and which serves to increase the general utility of the apparatus comprising the novel system.

Another object of this invention is the provision of a pumping system which may take the form of a gas operated fuel injection system for a combustion chamber in which the high temperature components of the system are isolated with respect to the other components, and a system in which there is a distinct separation between the combustion chamber and fuel storage components of the system.

A still further object of this invention resides in the provision of a unique gas operated fuel pumping system which utilizes a replaceable, disposable fuel container or cartridge thereby facilitating reloading and use of the injector.

Still another object of this invention lies in the provision of a gas operated fuel injection apparatus which incorporates automatic control means for the eflicient regulation of the complete operational cycle of the device.

Additional objects and advantages relating to the efficiency of operation, space requirements, and initial costs of the apparatus are inherent in the novel structures and combinations of the apparatus constituting this invention.

Still further objects and advantages of this invention will become more readily apparent to those skilled in the art when the following general statement and description are considered in the light of the accompanying drawings.

The nature of the present invention may be stated in general terms as relating to a gas operated pumping system including a collapsible wall fuel container, a gas generant chamber, an expansible chamber defined between the collapsible walls of the fuel container and the gas generant chamber, a combustion chamber-having communication with the fuel container, means providing communication between said gas generant chamber and a pressure generating chamber, and means transmitting pressure from the pressure generating chamber to the expansible chamber to effect transfer of the gas generant to the pressure generating chamber and fuel to the combustion chamber.

The present invention will be described in greater detail hereinafter with reference to the accompanying drawings in which the single figure of the drawing is a side elevation in vertical section of the apparatus constituting the present invention shown in part in detail and in part schematically.

Referring now to the accompanying drawings wherein there is shown an illustrative and operable embodiment of the present invention, the gas operated fuel injection system consists basically of a housing containing the fuel storage and fuel pumping components of the apparatus, and a housing 12 containing the gas pressure generat- ICC ing components of the system and combustion chamber with which it is associated.

The housing 10 consists of an elongated preferably cylindrical tank 14 having a removable cup-shaped head 16 at one end thereof which in turn is provided with an axial outlet opening 18 therethrough. The second closed end 20 of the housing is provided with an axial outlet opening 22 therein. The inner diameter of the cupshaped head 16 is of lesser dimension than that of the main body of the tank 14 to which the head is secured.

The housing 12 is located in spaced relationship to the housing 10 and consists of an elongated closed receptacle 24 divided internally intermediate its length by a partition wall 26 extending transversely thereof to define two end sections 28 and 30 within the housing. Internal section 28 within housing 12 is provided in a central portion thereof with an injector or nozzle 32 communicating externally of the housing, through a tube 34, with the central outlet 18 in the cup-shaped head of housing 10. This section of the housing 12 constitutes a pressure generating chamber within the housing.

Section 30 of housing 12 takes the form of a combustion chamber and is provided in one wall thereof with an injector or nozzle 36 which communicates through a tube 38 with the outlet 22 in the end 20 of the housing 10. The housing 12 is also provided with an exhaust outlet 74.

Gas generating section chamber 28 of the housing 12 is provided with an additional outlet or exhaust tube 40 which opens into housing 10 at a point in the wall of the tank 14 between its ends. Also, chamber 28 of housing 12 is provided with an orifice 42 in the partition wall 26 to provide restricted communication between chamber 28 and combustion chamber 30. i I

An elongated collapsible wall container 44 is positioned within tank 14 adjacent the closed end 20 thereof and is provided with an outlet fitting 46 which is received in the outlet opening 22 in the end wall of the tank and which is closed and sealed by a frangible or rupturable portion 48. A second collapsible wall container 50, of lesser diameter than container 44, filled with a gas generant liquid is positioned within the cup-shaped area of head 16 and is provided with an outlet fitting 52 which is received in outlet opening 18 of the head and which fitting is also closed and sealed by a rupturable portion 54.

The collapsible wall containers 44 and 50 may be constructed of thin metal such as stainless steel, aluminum and copper and the like or of flexible plastic such as polyethylene or rubber or combinations thereof.

In the tank 14 immediately inward from the cup-shaped head 16 there is located a differential area piston 56 provided with an annular portion 60 slidably mounted within the cup-shaped head 16 and in abutment with the flexible container 50 and an enlarged diameter section 62.slidably mounted within tank 14 and sealed with the side walls thereof by an O-ring or like sealing gasket or ring 64. A vent 65 is provided in the head 16 to prevent air from being trapped therein during movement of the piston 56. The largest section 62 of the piston 56 is normally disposed in spaced relationship from the innermost end' of the collapsible wall container 44 defining therebetween an expansible chamber 66 into which tube 40 opens.

To complete the structural arrangement of this system a small propellant charge flare or electric squib 68 is located Within the gas generating chamber 28 of housing 12. Each of the tubes 34 and 38 also may be provided with flow control valve 70 and 72 respectively which,

3 type and may be the same as the propellant contained in flexible wall container 44.

Suitable mono-propellants such as nitro-methane, 1- nitropropane, Z-nitropropane, l-nitrobutane, normal propyl nitrate, ethylene oxide and ethyl nitrate, may be eifectively employed as the propulsion fuel and the gas generant.

It is also pointed out that the gas generant may comprise a low boiling point liquid which expands into the gaseous form. However, in such cases the short burning time igniter or flare 68 is replaced with a flare adapted to burn throughout the operating period of the pump to supply the heat necessary to convert the liquid into the gaseous form. A simple thermite type flare would be satisfactory for such purpose.

In operation of the fuel injection apparatus disclosed, the propellant charge or flare 68 within the chamber 28 of housing 12 is suitably ignited, such as electrically, to produce gaseous products within the chamber to initially pressurize the chamber thus inducing their flow through tube 40 into expansible chamber 66 of housing 10. The pressurized gases introduced into expansible chamber 66 act on the largest surface area of the differential area piston 56 urging said piston in the direction of the cupshaped head 16 thereby exerting external force on the collapsible container 50 which causes the diaphragm 54 to burst. Continued movement of piston 56 under pressure maintained in chamber 66 by flare 68 expels gas generant from the collapsible container 50 through tube 34 to be injected through nozzle 32 into chamber 28 of housing 12. The gas generant injected into chamber 28 is ignited, decomposed or expanded, as the case may be, Within the chamber 28 by the hot gases liberated from the flare 68 thereby maintaining chamber 28 under pressure. A portion of this pressurized gas will continue to flow through tube 49 into expansible chamber 66 maintaining the continuous movement of piston 56 for the purpose of discharging further quantities of gas generant from the collapsible container 50 into the chamber 28. Another portion of the pressurized gases produced by the ignition of the gas generant in chamber 28 will be discharged from the chamber through the orifice 42, in the partition wall 26, into the combustion chamber 30 where it serves to ignite the primary propellant introduced into the combustion chamber through nozzle 36 in a manner to be described. The pressure within expansible chamber 66, which has been described as producing movement of differential area piston 56 to expel gas generant from container 50, also acts simultaneously against the inner end wall of the collapsible container 44 causing diaphragm 48 to rupture and forces the propellant in container 44 through tube 38 and injector 36 into the combustion chamber 30.

The continuous generation of pressurized gas in chamber 28 and introduction of a portion of this gas into expansible chamber 66 will cause continuous collapse of container 44 and consequently discharge of the fluid propellant therein through injector 36 and into the corribustion chamber.

The high pressure gases produced in combustion chamber 30 by ignition of the fluid propellant introduced into the chamber by nozzle 36 are discharged through a controlled outlet 74 to a turbine or like work producmg machine operable by such high pressure gases.

In construction of the apparatus constituting the embodiment hereinbefore disclosed the dimensions of nozzles 32 and 36, orifice 42 and gas outlet 74 and the presetting of valves 70 and 72 are so selected within relative ranges that the pressure maintained in chamber 28 dur mg operation of the apparatus will be greater than the pressures established in combustion chamber 38 during its operation. This maintains a pressure differential between these chambers suflicient to permit the pressurized gases within expansible chamber 66 to force the liquid propellant housed in container 44 into thfi. gqtnbllfitioll chamber 30 against the pressures normally incident to that chamber during operation. By the same token, the gas pressure within expansible chamber 66, which is consistent with pressure within chamber 28 is multiplied through the differential area piston to produce a higher pressure acting on the collapsible container 50 thus enabling injection of the gas generant therein into chamber 28 against the forces of the gas pressure developed therein.

The parameters of the system are determined by wellknown principles. For example, the rate of flow W of liquid through nozzle 32 is proportional to the square root of the difference in the pressures on the gas generant and the gas or pressure generating chamber 28 which difference is proportional to the pressure P which exists sensibly in both the expansible chamber 66 and gas generating chamber 28 and the pressure in chamber 28 is proportional to the flow rate through nozzle 32.

Thus

where k and K are constants.

Solving these equations results in W =k K=C where C is a constant. Similarly, P =K k =C where C is a constant. Obviously, therefore, the physics of the system are such that the pressure produced by the gasgenerating liquid is set by the conditions of the system and can only be changed by varying its geometry. Moreover, the flow rate, W of the gas-generating liquid is dependent only on the geometry of the system and the pressure in space 66, and since the latter pressure has been shown to be constant the flow rate W is also constant. For such reasons, the overall system will maintain a constant flow.

Because of the differential pressure areas maintained in the relationship as above described the apparatus will continue to function until either the gas generant or the liquid propellant material is exhausted. Additionally, it is important to note the flow of liquids from both collapsible containers will tend to maintain themselves at a constant rate since the physics of the apparatus structure are such that the pressure produced by the gas generant is set by the conditions of the system and can only be varied by variations in the geometry of the system.

The invention has been specifically disclosed for use in systems employing only monopropellants. However, the invention may also be employed with bi-propellants for the main fuel or the gas generant or both using two collapsible containers at one or both sides of the differ ential piston 56 as disclosed with respect to non-collapsi ble fuel and gas generant chambers in my co-pending application, Serial No. 604,860, filed August 20, 1956.

The particular propellants and gas generants designated in the above disclosure are for purposes of illustration only and it is further anticipated that the materials from which the components such as the collapsible wall containers and the like may be constructed may be varied to meet the exigencies of the job to be accomplished without departing from the scope and spirit of the present invention.

Having thus described and explained in detail the construction and operation of this invention, and having provided apparatus which accomplishes all of the objects and advantages heretofore attributed to the invention, what is desired to be claimed is:

l. A pumping system comprising a housing, a collapsible Wall fuel containing chamber in said housing, a .gas generant containing chamber in said housing, an expansible chamber containing diiferential pressure means between said fuel containing chamber and said gas generant containing chamber, a combustion chamber, first conduit means connecting said combustion chamber with said fuel containing chamber, a pressure generating chamhe sec d Conduit me ns connecting said pressure gencrating chamber with said gas generant chamber, and means for transmitting pressure from said pressure generating chamber to said expansible chamber thereby to effect simultaneous transfer of gas generant to said pressure generating chamber and fuel to said combustion chamber. I

2. A pumping system as defined in claim 1 wherein said pressure genenating chamber has communication with said combustion chamber through restricted means.

3. A pumping system as defined in claim 1 wherein said difierential pressure means is a differential area piston which forms a wall between said expansible chamber and said gas generant chamber.

4. A pumping system comprising a first housing, a collapsible wall fuel container, and a collapsible wall gas generant container in said first housing, a differential area piston slidably mounted in said first housing adjacent to said gas generant container and said fuel container, an expansible chamber in said first housing defined by the larger face of said piston and said fuel container; a second housing, a pressure generating chamber and a combution chamber in said second housing, first conduit means connecting said fuel container and said combustion chamber, second conduit means connecting said gas generant container and said pressure generating chamber, and third conduit means connecting said pressure generating chamber and said expansible chamber thereby to effect simultaneous transfer of gas generant to said pressure generating chamber and fuel to said combustion chamber.

5. A pumping system comprising a first housing, a

collapsible wall fuel container and a collapsible wall gas generant container in said first housing, a differential area piston slidably mounted in said first housing between said gas generant container and said fuel container, an expansible chamber in said first housing defined by the larger face of said piston and the collapsible wall of said fuel container, the smaller face of said piston being adjacent to the collapsible wall of said gas generant container; a second housing, a partition member dividing said second housing into a combustion chamber and a pressure generating chamber, an orifice in said partition member providing restricted communication between said pressure generating chamber and said combustion chamber, an ignitor in said pressure generating chamber, first conduit means connecting said fuel container and said combustion chamber, second conduit means connecting said gas generant container and said pressure generating chamber, and third conduit means connecting said pressure generating chamber and said expansible chamber thereby to efiect simultaneous transfer of gas generant to said pressure generating chamber and fuel to said combustion chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,408,111 Truax et al. Sept. 24, 1946 2,505,798 Skinner May 2, 1950 2,648,196 Mullen et a1. Aug. 11, 1953 2,683,963 Chandler July 20, 1954 2,711,630 Lehman June 28, 1955 2,858,670 Grieve et a1. Nov. 4, 1958

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