Apparatus for positive feeding of fluid propellants
[4 1 Apr. 29, 1975 United States Patent [1 1 Brajer et al.  
 ZZZ/386.5 X  
 .. 60/260 X ZZZ/38645 60/259 ZZZ/386.5 X  
  e k c O r K Erickson Dodgc...... Young Primary E.raminer\/erlin R. Pendegrass [73] Assignee:  
 [57] ABSTRACT This disclosure relates to a bipropellant expulsion system for a rocket engine comprising a pair of receptacles encapsulating separate liquid propellants and [22] Filed: Aug. 16, I966 App]. No: 574,494  
  WhlCh may be inserted into a containing vessel or tank 158/501; as a unit and which operate as rolling diaphragms 239/323 when pressure is applied to one end together with a shear slide and gas producer arrangement for opening F23n 1/00; F23r 1/02 ZZZ/386.5. 95;  
 [51] Int Cl [58] Field of Search outlet ports from the receptacles and operating the rolling diaphragms.  
 References Cited UNITED STATES PATENTS 2,970.452 Beckman ct 222/386.5 X 7 Claims, 1 Drawing Figure APPARATUS FOR POSITIVE FEEDING OF FLUID PROPELLANTS This invention relates generally to positive displacement, liquid expulsion systems in which a diaphragm is attached to a liquid containing tank and to a piston therein which is propelled by fluid pressure through the tank to expel the liquid. and more particularly to an improved expulsion tank and diaphragm construction and arrangement.  
  Expulsion systems of this type are particularly useful in the liquid propellant expulsion systems of packaged liquid propellant rocket engines which may be stored for long periods before their use. It has been found. however, that the propellants used in packaged liquid powerplants are not compatible with the ultra-high strength steels normally used in the tank construction although it has been determined that they are compatible (for long term storage) with aluminum.  
  Another problem has arisen through the diaphragms employed which are thin, flexible cylinders and are turned inside out or back 180 within themselves by the piston during the liquid expulsion movement of the latter. The fluid pressure acting on the piston also acts laterally on the flexible diaphragm cylinder so that it is necessary to provide some type of supporting means for the walls thereof. A further problem of these expulsion systems resides in the fact that current tank constructions require not only multiple welds and thickened walls but welds between dissimilar walls (e.g.. Bi-Braze joints).  
  The main object of the present invention is to provide a lightweight positive liquid expulsion tank construction which will eliminate the above and other difficulties by an efficient combination and novel use of materials.  
  An important object of the present invention is to provide an improved positive liquid expulsion apparatus formed of separate tank, diaphragm, etc. units which may be readily assembled and which does not require welding, brazing, etc., between dissimilar materials.  
  Another important object of the present invention is to provide an improved positive liquid expulsion apparatus of the type described in which the tank may be constructed of material with which the contained liquid or liquids is incompatible due to the encapsulating of the liquid within flexible rolling metal diaphragms of compatible material, and the tank is compartmentized by utilizing the aft end of the forward diaphragm as the center header.  
  A further important object of the present invention is to provide an improved positive liquid expulsion apparatus of the type described in which the tank and the flexible metal diaphragms may be constructed and assembled as independent units and include a shear slide which is operative by pressurizing gas to open the liquid discharge ports of the liquid containing diaphragm or diaphragms.  
  Other objects and advantages of the present invention will become apparent during the course of the following description.  
  In the drawings one embodiment of the invention has been shown. In this showing:  
  FIG. 1 is a fragmentary, central longitudinal view of the liquid expulsion apparatus in the storage position showing the tank for the liquids to be expelled, the expelling pistons, the encapsulating diaphragms and the pressure operated shear slide.  
  Referring to the drawings. numeral designates a liquid expulsion apparatus as a whole which comprises a tank 12 which may be of any desired shape and is shown as cylindrical, flexible annular liquid or propellant containing (fuel and oxidizer) aluminum dia&#39; phragms l4 and 16, and positioned centrally thereof, a pressure gas generating chamber 18 and an aluminum shear slide housing 20.  
  The tank 12 has a hemispherical aft end terminating in a flanged opening 22 having a shoulder 23 against which the shear slide housing is seated. The forward end of the tank is closed by an annular header 24 having a removable, centrally positioned cap 26. suitably secured thereto as at 27. Ultra-high strength steels may be used for the tank elements inasmuch as they are never in contact with the corrosive liquids or propellants.  
  A steel tube 28 for aligning and furnishing support to the inner annular wall 32 of the forward flexible metal diaphragm I4, is coextensive therewith and projects inwardly from the cap the header 26 so as to be insertable or removable with the latter. The gas generator 18 which contains a solid grain propellant l9 ignitable on command. is inwardly spaced from and fixed to the forward end of the tube 26a and includes circumferentially spaced ports 29 through which pressurized gases pass to act on the forward end of the rolling metal diaphragm 14 during operation.  
  The tank 12 is compartmentized by an annular aluminum plate or header 30 which reinforces the tank 12 and forms the aft end of the flexible diaphragm 14 which has inner and outer walls 32, 34 and is closed at its forward end by an annular aluminum piston 36 having a fill port 37. In applications where unusually high operating temperatures are to be encountered, an insulating layer 38 may be employed and extend from the aft end of the steel tube 28, around it and between it and the diaphragm l4, and around the piston 36 to a point 39 intermediate the wall of the tank 12. Similar insulation may be employed as shown about the aft liquid containing diaphragm 16.  
  The inner wall of the diaphragm 14 is provided at its aft end with a plurality of circumferentially spaced passages 40 which communicate with the intcrior of an aluminum tube or conduit 42 fixed to the header 30 and extending aft thereof which supports at its aft end, the shear slide housing 20. The aft end of the inner and outer walls of the aft flexible rolling diaphragm 16 are secured to the housing 20 as at 44 and 45 and the inner wall extending forwardly thereof to its piston 46 is aligned and supported by a second steel tube 48 outwardly spaced from the conduit 42 to form a pressurizing gas passage 49, whose forward end abuts the aluminum header 30.  
  The forward flexible rolling diaphragm 14 is hermetically sealed to its header 30 as at 50 and 51 and the conduit 42 is sealed to the shear slide housing as at 52. Thus the liquids contained in the aft diaphragm l6 and in the forward diaphragm 14 (which also fill the conduit 42 to the shear slide housing 20) are completely encapsulated in compatible aluminum material,  
  The shear slide housing 20 to which the aft diaphragm 16 is hermetically sealed is provided with a liquid fill port 54, a tubular shear slide 56, and a discharge outlet 58 through which the propellants (or liquid) is discharged to the combustion chamber (not shown) of a rocket engine. The propellants when pressurized, enter the housing by way of ports 60, 61 from the forward diaphragm and conduit 40, 42 and from the aft diaphragm 16, respectively, the ports being initially closed as shown in the drawings by cup shaped hermetic seals 62 supported in recesses 64 of the shear slide 56. The slide is provided with a shoulder 66 and an upstream or forward annular face 67 against which pressurizing gases act during operation to effect movement of the slide 56 from the position shown to a position where its shoulder 66 engages and is arrested by a shoulder 68 formed on the housing 20. lntcrmixing of the propellants (which are usually hypergolic) is prevented by a flexible diaphragm 70 hermetically secured to the slide 56 and the slide housing 20, and by O-ring seals 72 during movement of the slide upon operation.  
  The inward spacing of the gas generator chamber 18 from the tube 28 provides a pressurizing gas passage 74 which passes aft and through a passage 76 in the header to act against the diaphragm piston 46 and passes through the passage 49 to act against the face 67 of the shear slide 56.  
 OPERATION As stated the units of the apparatus are constructed and stored as separate units and are prepared for oper ation by hermetically securing the aft diaphragm 16 to the shear slide housing and filling both of the diaphragms with liquid (fuel or oxidizer). The shear slide housing 20 already being hermetically sealed to and mounted on the aft end of the conduit 42 with the seals 62 and the shear slide 56 in place and in the position shown. The annular header 24 of the tank 12 not yet being in place. the assembled and filled diaphragm 14 and 16 and shear slide housing 20 units are inserted from the left end until the housing projects through the flanged opening 22 and the housing engages the shoulder 23. The steel header 24 is now secured to the left end of the steel tank 12 as by welding.  
  The solid propellant 19 in its housing 18 and the tube 28 are now fixed to the tank header cap 26 and the assembly inserted centrally of the tank to the position shown and the cap is secured to the header. Upon ignition of the solid grain propellant 19, the pressurizing gases flow through the port 29 to act against the piston 36 of the forward diaphragm 14 to pressurize the propellant therein. Simultaneously, the gases flow aft through passages 74 and 76 to act against the piston 46 of the diaphragm 16 and to pressurize its encapsulated propellant and to act against the face 67 of the shear slide 56.  
  When the pressure of the gases has built up adequately against the face 67, the slide. is forced to move to the right to the housing shoulder 68 which movement shears the seals 62 and admits the propellants to the shear slide housing 20 from which one passes centrally of the slide by way of discharge outlet 58 and the other separately around the slide by a discharge outlet 80.  
  While the principles of the invention have been disclosed in connection with bi-propellants, it is obvious that they are equally applicable to monopropellants, or multipropellants all encapsulated in compatible, flexible diaphragms. It will now be apparent that the invention ensures propellant and storage material compatibility, extreme light weight of the apparatus through the use of flexible aluminum diaphragms and ultra-high strength steel for the tank, and a material reduction in production costs by reducing the number of welds and eliminating conventional local thickening of walls.  
 It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example thereof and that various changes in the shape, size, and arrangement of parts may be resorted to without departure from the spirit of the invention or the scope of the subjoined claims.  
 What is claimed is:  
  1. A fluid expulsion system comprising a tank for storing a fluid and having an outlet adjacent one side, a diaphragm in said tank having a rigid piston at one side and the remaining walls being flexible and composed of a material compatible with the fluid being stored and completely encapsulating the stored fluid, a slide movable relative to diaphragm, a seal in the form of a cup projecting into a recess in the slide for closing the outlet and sheared by the slide to connect the diaphragm to the outlet, means for supplying a pressurizing fluid to actuate the slide and rupture the seal in the outlet and actuate the piston to roll the diaphragm back on itself for discharging stored fluid therefrom, and said piston having a shape corresponding to the shape of the diaphragm at its opposite side for expelling all of the fluid therefrom.  
  2. A fluid expulsion system in accordance with claim 1 in which a conduit is provided at the axis of the tank to form an annular space in the tank, and said diaphragm being of annular shape with the conduit at its axis and its outer-peripheral wall engaging the inner wall of the tank.  
  3. A fluid expulsion system comprising a cylindrical tank having an axial conduit forming an annular space therebetween for the storage of liquids and at least one outlet through which liquid may be expelled therefrom, a first propellant containing diaphragm of a flexible material surrounding said conduit and compatible with the fluid being stored and forming a chamber completely encapsulating the stored fluid, a second liquid containing diaphragm of a flexible material surrounding said conduit in axial alignment with the first diaphragm and compatible with the fluid being stored therein and forming a chamber completely encapsulating its stored fluid, seals preventing flow of liquids from said diaphragms to the outlet opening from the tank, a slide for rupturing said seals, said diaphragms being constructed to roll inside out when a motive fluid is supplied to one end, and means comprising a gas generator and passages in said tank for supplying a pressurizing fluid to actuate said slide and one side of said diaphragms to rupture the seals and roll the diaphragms back on themselves to discharge their stored liquid therefrom.  
  4. A fluid expulsion system in accordance with claim 3 in which separate outlet openings are provided for the separate diaphragms, and a seal for each diaphragm.  
  5. A fluid expulsion system in accordance with claim 3 wherein the first diaphragm comprises a piston at one side operated by the pressurizing fluid to roll the diaphragm and expel liquid therefrom, a header at the opposite end of the diaphragm for strengthening the tank and dividing it into separate compartments, and said piston and header having the same shape to expel all of the liquid from the diaphragm during a rolling operation.  
  6. A fluid expulsion system in accordance with claim 3 in which a cylindrical chamber is provided at the axis of the first mentioned diaphragm having the piston and header a chamber at the axis of the second mentioned diaphragm and forming an extension of the first mentioned diaphragm, said axial chamber and second mentioned diaphragm having axially spaced outlet ports in the conduit, and the seals closing the axially spaced ports and projecting into the slide, a gas generating material in the first chamber, and the passages in the tank directing gas from the gas generator to actuate the piston and slide.  
  7. A fluid expulsion system. a tank for storage of at least one liquid therein. said tank terminating at its aft end in a flanged outlet opening having an internal shoulder, a conduit means including a tube mounted in said tank with one end extending through said opening and engaging said shoulder. a liquid containing diaphragm ofa flexible material mounted in said tank and completely encapsulating said liquid therein. said conduit means having a port therein communicating with the interior of said diaphragm, means for sealing said port. and a slide mounted on said tube and operative to open said sealing means. said liquid containing diaphragm. conduit means and slide being inserted into said tank as a unit and means including a gas generator for actuating said slide to open said outlet port and apply pressure to said diaphragm and effect discharge of liquid through said port into said conduitv