Power plants – Reaction motor – With thrust direction modifying means
Reexamination Certificate
1998-12-17
2001-08-21
Kim, Ted (Department: 3746)
Power plants
Reaction motor
With thrust direction modifying means
C060S279000, C251S063000, C251S282000
Reexamination Certificate
active
06276125
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to valving devices. More particularly, the invention relates to a valve for regulating gas flow from a rocket motor or gas generator to a reaction jet nozzle.
BACKGROUND OF THE INVENTION
It is well known in the art to employ reaction jets that vary the pitch, yaw, spin rate and other dynamic characteristics of a missile or space vehicle in flight. A typical reaction jet comprises a jet nozzle and a housing defining a main stage plenum. An annular passage supplies pressurized fluid to the main stage plenum to be discharged through the jet nozzle, thereby creating reaction jet thrust. Disposed within the reaction jet housing is a valve member, often comprising a poppet valve. The poppet valve regulates the flow of pressurized fluid from the annular passage through the jet nozzle by moving alternately between a fully opened position and a closed position.
In the fully open position, the poppet valve is retracted from a position abutting a valve seat formed between the annular passage and the nozzle. In the closed position, the poppet valve is position in abutment with the valve seat thereby sealing the annular passage from the plenum. The poppet valve is urged between the open and closed positions by the pressure balance between the fluid pressure in the plenum and the fluid pressure in a main stage actuation chamber. When the pressure in the main stage actuation chamber is greater than the pressure in the plenum, the poppet valve is urged towards the closed position. Conversely, when the pressure in the main stage actuation chamber drops such that the pressure in the plenum is greater than the pressure in the main stage actuation chamber, the poppet valve is urged toward the fully open position. The actuation chamber normally is axially aligned with the poppet valve and disposed on the opposite side of the poppet valve from the plenum. Accordingly, the actuation chamber is of approximately the same diameter as the poppet valve such that the working volume of the actuation chamber volume is approximately equal to the swept volume of the poppet valve.
Typically, the main stage actuation chamber is pressurized and vented by a pilot valve. Control of pilot valve pressurization and venting conventionally is achieved by a solenoid-actuated flapper valve, which opens and closes to admit or vent high pressure gas to and from the main stage actuation chamber.
Because missiles and space vehicles typically move at high rates of speed, it is critical to the control of such craft that the reaction jets have a high rate of response between their respective on and off positions. Accordingly, it is desirable to minimize the time and work necessary to move the poppet valve between the open and closed positions. At the same time, in order to preserve desired mass flow rate through the nozzle, the plenum and poppet valve diameters must be maintained. These objectives may be achieved by minimizing the actuation chamber volume and/or minimizing aerodynamic resistance of the poppet valve member movement within the valve body.
Accordingly, a need exists for a reaction jet valve that provides maximum flow rate through the nozzle with minimal time and work needed to control the flow through the nozzle.
SUMMARY OF THE INVENTION
In accordance with the present invention, a valve is disclosed for regulating the flow of a pressurized working fluid through a nozzle having a nozzle throat.
In a preferred embodiment of the invention, the valve comprises a valve body defining a valve bore, a pressure inlet and a nozzle plenum. The nozzle plenum fluidly communicates with the nozzle throat. A poppet valve seat is disposed between the pressure inlet and the nozzle plenum. A poppet valve member is slidably disposed within the valve bore. The valve member comprises a first end disposed proximal the valve seat and a second end distal the valve seat. The first end comprises a valve face and the second end comprises first and second rear surfaces. The second rear surface is spaced apart from the first rear surface. The first rear surface cooperates with the valve bore to define a rear chamber. The second rear surface cooperates with the valve bore to define an actuation chamber, the volume of which is independent of the valve member diameter. The valve member is responsive to pressure in the second chamber to move between a first position and a second position. In the first position, the valve face is spaced apart from the valve seat thereby permitting fluid communication between the pressure inlet and the nozzle plenum. In the second position, the valve face is seated against the valve seat thereby precluding fluid communication between the pressure inlet and the nozzle. A conduit provides fluid communication between the nozzle plenum and the first chamber, thereby providing a pressure balance between the front and rear surfaces of the valve member. This pressure balance, in turn, reduces the total force that must be applied by the actuator chamber in order to cause the valve member to move.
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patent: 5203372 (1993-04-01), Freiler
patent: 5456425 (1995-10-01), Morris et al.
Allied-Signal Inc.
Kim Ted
Newberry, Esq. Keith
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