Abstract:
A compact, valve assembly (10) is provided having multiple chambers. A forward chamber (14) retains dual T-shaped blades (36) having shaped orifices (38) for controllably metering at least two fluids passing through the valve assembly. The valve assembly is also provided with a servo-valve assembly (70) and a piston indicator (62) assembly in cooperative association with the valve assembly.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a valve assembly for controlling fluid flow. More particularly, the present invention is directed to a fluid injection system for injecting propellants such as fuel into a combustion chamber of a fluid fueled rocket engine. For example, the valve assembly may be incorporated into a vehicle such as a re-entry interceptor system having four divert rocket engines in a cruciform arrangement. 
     2. Background Art 
     Various propulsion systems, discussed below and incorporated herein by reference, have means for injecting propellant(s) into the combustion chamber of a rocket engine. 
     Jaqua (U.S. Pat. No, 4,326,377) describes a system for injecting propellant utilizing a piston including orifices which direct propellant from the injection chamber into the combustion chamber. This is accomplished, in part, by the cooperation of a pair of valve members having concentric sleeves slidably mounted respectively on the inside and outside surfaces of the tubular portion of a piston. 
     Horner (U.S. Pat. No. 3,088,406) utilizes an injector pump and a solenoid assembly which function together to inject a predetermined amount of fuel into a rocket combustion chamber. The injector pump housing encloses three stepped pistons on a single shaft which can be activated by a driving gas derived from the thrust chamber through a conduit communicating therebetween. The driver piston is the motivating force displacing a fuel injector piston and an oxidizer injector. This arrangement allows the entire amount of predetermined quantities of fuel and oxidizers stored in the injector pump cylinder to be injected into a combustion chamber. 
     BRIEF SUMMARY AND OBJECTS OF THE INVENTION 
     The valve assembly of the present invention is both compact and designed to insure reliable and optimal performance when a controlled flow of two fluids is desired. 
     A valve assembly housing chamber having fluid inlet and outlet ports includes slidable blades positioned in functional relationship proximate these ports. Each blade has formed therein a shaped orifice or channel. A yoke, in cooperation with a piston and servo-assembly links the blades to a closed loop feedback control system. 
     When activated, the valve assembly is capable of controlled displacement or axial movement of the blades within the housing chamber. In turn, each blade orifice may be selectively positioned proximate a fluid inlet and outlet port to allow a flow of fluid(s) supplied from a remote source to pass through the valve assembly. 
     Accordingly, it is an object of this invention to provide a valve assembly for controllably mixing or dispensing diverse fluid. 
     Another object of this invention is to provide a fluid injection system for injecting propellants into a combustion chamber of fluid-fueled rocket engine. 
     These and other objects and features of the present invention will be apparent from the following detailed description, taken with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view, partially broken away, of the valve assembly of the present invention. 
     FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1. 
     FIG. 3 is a cross-sectional view of the valve assembly of the present invention shown in a preferred embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to the drawings and in particular to FIG. 1 thereof, there is shown a valve assembly (10) for controlling the flow of two fluids from a remote source for the intimate mixing or interaction thereof. This mixing and/or interaction may find application, for example, in a fluid sprinkling, spraying or diffusing apparatus but the preferred embodiment as described in greater detail below is a valve assembly in a fluid injection system for controllably injecting propellants into a reaction engine combustion chamber. 
     Referring to the drawings in detail, 10 indicates the valve assembly according to the present invention. Valve assembly includes a housing structure 12 defining forward 14, central 16 and aft chamber 18. 
     As shown in FIG. 2, a fluid inlet 20 passes through an upper wall surface of the housing structure and terminates within a first compartment 22 in the forward chamber formed by partition 24. While not shown, a second fluid inlet also is provided in the housing structure which, as with the first fluid inlet, communicates with a second compartment identical to and in the same plane as compartment 22 in the forward chamber 14 formed by partition 24. Each compartment terminates at an upper surface of the corresponding T-shaped blade. Corresponding fluid outlets 26 are positioned beneath the fluid inlets in the base of the valve assembly housing for conducting fluids from the valve assembly into an injector. 
     Openings 28 and 30 within the rear wall 32 of each of the parallel compartments of chamber 14 form a passageway from each of these compartments into the central chamber. Slidable T-shaped blades 36 having a top section and a base are positioned and retained within chamber 14. Aligned, shaped orifices 38 are formed within each blade near a forward portion thereof and pass through bottom 42 of each blade from the top to the bottom surface. 
     The shape of the orifices is selected to provide an equal percentage orifice shape which produces a change in flow corresponding to a change in blade position that is a constant percentage of the flow prior to the change in blade position. In the present example as shown in FIG. 1, wedge-shaped orifices in each blade provide a controlled oxidizer to fuel mixture ratio over the complete range of fluid flow. That is, the mixture ratio can be held constant or may be varied as needed to optimize system performance. A more detailed discussion of orifice shapes as affecting flow characteristics is available in ISA Handbook of Control Valves, 2d Edition (1976), incorporated herein by reference. 
     The base 44 of each T-shaped blade extends from the top section 40 and passes through openings 28,30 within the rear wall 32 of each parallel compartment and into the central chamber 16. Seals or gaskets 46 are provided to ensure leak-proof seals in the valve assembly. 
     Within the central chamber 16 there is positioned a T-shaped yoke 48 having a top section 50 and a base section 52. The top 50 of the yoke is functionally joined, such as by pinning, welding and the like to the base 52 of each of the blades 36. 
     A passageway 54 (see FIG. 2) communicating between the central and aft chambers accommodates shaft 56 of a piston 58 housed in aft chamber 18. The shaft 56 extends through passagway 54 and is attached by a threaded coupling 60 at the base of the shaft 56 to the base 52 of yoke 48. 
     In cooperative association with the valve assembly housing structure 12, is a position indicator assembly 62 and servo-valve assembly 70 attached thereto. 
     The position indicator assembly 62 is provided with a housing 64 having a chamber 66 formed therein. A position indicator probe 68 having one end fixedly attached to the aft section of piston 58 is slidably retained within chamber 66. As previously indicated, the seals or gaskets 46 ensure leak-proof seals for the functional components of the valve assembly 10. 
     The servo-valve assembly 70 includes an electromagnetic motor 72 for positioning a valving mechanism within assembly 70, and ports 74,76 communicating with the aft chamber of the valve assembly 10. The ports are positioned so that fluid supplied to the servo-valve assembly 70 by passageway 78 leading from compartment 22 of the valve assembly may be directed into the aft chamber in front of or to the rear of piston 58. 
     As indicated previously, FIG. 3 represents the valve assembly in functional relationship with a rocket engine thrust chamber 80. This embodiment will be utilized to explain the operation of the valve assembly for controlling the flow of two fluids, in this instance, a propellant fuel such as hydrazine and an oxidizer, from a remote storage source such as an oxidizer tank and a fuel tank (not shown). 
     As seen in FIGS. 2 and 3, fuel under pressure enters inlet 20 and passes through passageway 78 to the servo-valve assembly 70. Upon activation of the valve assembly by a remote controller (not shown), the motor of the servo-assembly is activated which in the allows a portion of the fuel to be selectively introduced or withdrawn from the aft chamber to function piston 58. The remote controller, which may be commanded by an onboard computer or by a ground controller, is able to determine the position of the blades in the forward chamber by the position of the piston indicator probe 68 housed within the piston indicator assembly 62. 
     It is to be understood that the servo-assembly 70 is capable of introducing or withdrawing fluid from either side of the piston 58 positioned within the aft chamber upon command. In this manner, the piston may be moved forward or aft as desired to control the positioning of the T-blades 36 in the forward chamber which in turn determines the position of the shaped orifices 38 therein. When a predetermined degree of thrust or impulse is desired, the onboard control system or controller, as the case may be, activates motor 72 which in turn directs fluid through one of the ports into chamber 18. The blades are simultaneously moved aft to a predetermined position and at this time both fuel and oxidizer are allowed to pass through the valve housing 12, the injector 84 and into thrust chamber 80. Any fluid or oxidizer that may leak past seals 46 during operation and into central chamber are allowed to pass to the atmosphere through port 86. In this manner, interaction of the hypergolic propellant mixture within the central chamber 16 is precluded. 
     In thrust chamber 80 the hypergolic reaction converts the fuel components into high-pressure gases which are in turn converted into thrust for propelling or directing the vehicle as desired. 
     It will of course be realized that various modifications can be made in the design and operation of the present invention without departing from the spirit thereof. Thus, while the principal, preferred construction, and mode of operation of the invention have been explained, it should be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically illustrated and described.