A gas control valve is configured to controllably supply propellant gas to a thruster so that the thruster may produce thrust over a relatively wide range, and so that the thruster exhibits relatively fine minimum impulse bit (MIB) performance. The gas control valve includes a pilot stage having a p
A gas control valve is configured to controllably supply propellant gas to a thruster so that the thruster may produce thrust over a relatively wide range, and so that the thruster exhibits relatively fine minimum impulse bit (MIB) performance. The gas control valve includes a pilot stage having a pilot valve, and a main stage having a main valve. The gas control valve responds to control signals supplied to the pilot stage and is configured such that for commands of relatively short duration, only the pilot valve responds. Conversely, for commands of relatively longer duration, the pilot valve and main valve both respond.
대표청구항▼
1. A gas control valve, comprising: a pilot stage including an inlet port, a pilot chamber, and a valve, the pilot stage inlet port adapted to receive pressurized gas from a pressurized gas source, the pilot stage adapted to receive control signals and operable, in response to the control signals, t
1. A gas control valve, comprising: a pilot stage including an inlet port, a pilot chamber, and a valve, the pilot stage inlet port adapted to receive pressurized gas from a pressurized gas source, the pilot stage adapted to receive control signals and operable, in response to the control signals, to move the pilot stage valve between a closed position, in which the pilot stage inlet port is not in fluid communication with the pilot stage pilot chamber, and an open position, in which the pilot stage inlet port is in fluid communication with the pilot stage pilot chamber; anda main stage including an inlet port, a control pressure port, an outlet port, and a valve, the main stage inlet port adapted to receive pressurized gas from the pressurized gas source, the main stage control pressure port in fluid communication with the pilot stage pilot chamber, the main stage valve responsive to differential gas pressure between the main stage inlet port and the pilot stage pilot chamber to move between a low flow position and a plurality of high flow positions,wherein:the pilot stage valve comprises: a flapper disposed at least partially within the pilot stage pilot chamber and movable therein; anda substantially spherical valve element disposed within the pilot stage pilot chamber between the flapper and the pilot stage inlet port, the substantially spherical valve element at least partially responsive to movement of the flapper to move between a first position and a second position, which correspond to the closed position and the open position, respectively,and wherein: in the low flow position, the main stage control pressure port is in fluid communication with the main stage outlet port and the main stage inlet port is not in fluid communication with the main stage valve outlet port, andin each of the plurality of high flow positions, at least the main stage inlet port is in fluid communication with the main stage valve outlet port. 2. The valve of claim 1, further comprising: a spring coupled to the flapper and configured to supply a bias force thereto that urges a portion of the flapper toward the pilot stage inlet port, to thereby urge the substantially spherical valve element toward the first position; andan actuator coupled to the flapper, the actuator adapted to receive the control signals and operable, in response to the control signals, to supply an actuation force to the flapper that urges the portion of the flapper away from the pilot stage inlet port, to thereby allow the substantially spherical valve element to move toward the second position. 3. The valve of claim 2, wherein: the flapper is rotationally mounted and rotatable in a first rotational direction and a second rotational direction;the bias force urges the flapper to rotate in the first rotational direction; andthe actuation force urges the flapper to rotate in the second rotational direction. 4. The valve of claim 2, wherein the actuator comprises a solenoid. 5. The valve of claim 1, wherein the main stage valve comprises: a valve element in fluid communication with the main stage inlet port and movable between a first position, in which the main stage inlet port is not in fluid communication with the main stage outlet port, and a second position, in which the main stage inlet port is in fluid communication with the main stage valve outlet port;a main stage actuator configured to at least selectively move the valve element from the first position to the second position, the main stage actuator comprising: a housing portion having an inner surface that defines an actuator chamber,an actuation element disposed within the actuator chamber and including at least a first end and a second end, the actuation element first end in fluid communication with the main stage control pressure port, the actuation member second end at least engaging the valve element, anda flow passage including an inlet and an outlet, the flow passage inlet in fluid communication with the main stage control pressure port, the flow passage outlet in fluid communication with the main stage outlet port. 6. The valve of claim 5, wherein the flow passage is formed in and extends through the actuation element. 7. The valve of claim 6, wherein the actuation element comprises a piston including at least a first end and a second end, the piston first end in fluid communication with the main stage control pressure port, the piston second end at least engaging the valve element. 8. The valve of claim 6, wherein the flow passage is formed by a clearance between the housing inner surface and the actuation element. 9. The valve element of claim 8, wherein the actuation element comprises: an end element that is at least partially spherical; anda push rod coupled to the end element and at least engaging the valve element. 10. A gas control valve, comprising: a pilot stage including an inlet port, a pilot chamber, a flapper, and a substantially spherical valve element, the pilot stage inlet port adapted to receive pressurized gas from a pressurized gas source, the flapper disposed at least partially within the pilot stage pilot chamber and movable therein, the substantially spherical valve element disposed within the pilot stage pilot chamber between the flapper and the pilot stage inlet port, the valve element at least partially responsive to movement of the flapper to move between a first position, in which the pilot stage inlet port is not in fluid communication with the pilot stage pilot chamber, and a second position, in which the pilot stage inlet port is in fluid communication with the pilot stage pilot chamber; anda main stage including an inlet port, a control pressure port, an outlet port, and a valve, the main stage inlet port adapted to receive pressurized gas from the pressurized gas source, the main stage control pressure port in fluid communication with the pilot stage pilot chamber, the main stage valve comprising: a valve element in fluid communication with the main stage inlet port and movable between a low flow position, in which the main stage inlet port is not in fluid communication with the main stage outlet port, and a plurality of high flow positions, in which the main stage inlet port is in fluid communication with the main stage valve outlet port, anda main stage actuator responsive to differential gas pressure between the main stage inlet port and the pilot stage pilot chamber to move the main stage valve element between the low flow position and the plurality of high flow positions, the main stage actuator comprising: a housing portion having an inner surface that defines an actuator chamber,an actuation element disposed within the actuator chamber and including at least a first end and a second end, the actuation element first end in fluid communication with the main stage control pressure port, the actuation element second end at least engaging the valve element, anda flow passage including an inlet and an outlet, the flow passage inlet in fluid communication with the main stage control pressure port, the flow passage outlet in fluid communication with the main stage outlet port. 11. The valve of claim 10, further comprising: a spring coupled to the flapper and configured to supply a bias force thereto that urges a portion of the flapper toward the pilot stage inlet port, to thereby urge the valve element toward the first position; andan actuator coupled to the flapper, the actuator adapted to receive the control signals and operable, in response to the control signals, to supply an actuation force to the flapper that urges the portion of the flapper away from the pilot stage inlet port, to thereby allow the valve element to move toward the second position. 12. The valve of claim 10, wherein: the flapper is rotationally mounted and rotatable in a first rotational direction and a second rotational direction;the bias force urges the flapper to rotate in the first rotational direction; andthe actuation force urges the flapper to rotate in the second rotational direction. 13. The valve of claim 10, wherein: the actuation element comprises a piston including at least a first end and a second end, the piston first end in fluid communication with the main stage control pressure port, the piston second end at least engaging the valve element; andthe flow passage is formed in and extends through the actuation element. 14. The valve element of claim 10, wherein the actuation element comprises (i) an end element that is at least partially spherical and (ii) a push rod coupled to the end element and at least engaging the valve element; andthe flow passage is formed by a clearance between the housing inner surface and the end element. 15. A propellant management control system, comprising: a propellant gas generator having propellant disposed therein, the propellant configured to generate propellant gas upon being ignited;a controller operable to selectively supply control signals; anda propellant gas control valve coupled to receive propellant gas from the propellant gas generator, the propellant gas control valve further coupled to receive the control signals and operable, in response thereto, to selectively discharge the received propellant gas, the propellant gas control valve comprising: a pilot stage including an inlet port, a pilot chamber, and a valve, the pilot stage inlet port coupled to receive propellant gas from the propellant gas generator, the pilot stage coupled to receive the control signals and operable, in response thereto, to move the pilot stage valve between a closed position, in which the pilot stage inlet port is not in fluid communication with the pilot stage pilot chamber, and an open position, in which the pilot stage inlet port is in fluid communication with the pilot stage pilot chamber; anda main stage including an inlet port, a control pressure port, an outlet port, and a valve, the main stage inlet port coupled to receive propellant gas from the propellant gas generator, the main stage control pressure port in fluid communication with the pilot stage pilot chamber, the main stage valve responsive to differential gas pressure between the main stage inlet port and the pilot stage pilot chamber to move between a low flow position and a plurality of high flow positions, wherein: in the low flow position, the main stage control pressure port is in fluid communication with the main stage outlet port and the main stage inlet port is not in fluid communication with the main stage valve outlet port, andin each of the plurality of high flow positions, at least the main stage inlet port is in fluid communication with the main stage valve outlet port. 16. The system of claim 15, wherein: the control signals comprise pulses, each pulse having a duty cycle; andthe propellant gas control valve is configured such that (i) the main stage valve is in the low flow position when the duty cycle of the control signal pulses is less than a predetermined duty cycle value and (ii) the main stage valve moves to a high flow position when the duty cycle of the control signal pulses is greater than the predetermined duty cycle value. 17. The system of claim 15, wherein the controller is further operable to selectively supply the control signals to control propellant burn rate. 18. The system of claim 15, wherein the controller is further operable to selectively supply the control signals to control propellant gas pressure in the propellant gas generator. 19. The system of claim 15, wherein the controller is further operable to selectively supply the control signals to control generation of propellant gas pressure pulses in the propellant gas generator.
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