Rotary motion failsafe gate valve actuator
First Claim
1. A valve actuator for a valve comprising:
- a housing having a fluid pressure inlet, a fluid pressure exhaust, and an inner sealing shoulder;
a rotatable screw shaft arranged in said housing connectable at one end to said valve;
a ball bearing nut mounted on the other end of said shaft and forming a piston longitudinally movable in said housing from a first to a second position;
biasing means surrounding said screw shaft engaging said piston and urging said piston to said first position thereof;
said piston containing peripheral seals for sealing engagement with the inner wall of said housing;
said piston sealingly engaging said inner sealing shoulder of said housing when said piston is in said second position thereof; and
means connected to said piston engaging said housing to prevent rotation of said piston.
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Accused Products
Abstract
An hydraulically operated failsafe valve actuator for use on non-rising valve stems, particularly in a subsea environment. A rotatable shaft is connected to the non-rising valve stem. In one embodiment the valve is actuated to open by a fluid pressure operated motor acting against the bias of a spring. Means connects means linearly movable along the shaft and converts the linear movement of the linear movable means to rotary movement of the shaft. Spring means moves the linearly movable means in one direction to cause the shaft to rotate in one direction. Fluid pressure means, including a fluid pressure operated motor, rotates the shaft in an opposite direction to cause the linearly movable means to move in an opposite direction along the shaft. In another embodiment the valve is actuated to open by a fluid pressure operated piston acting against the bias of the spring. The piston is mounted on the rotatable shaft and moves linearly along the shaft to cause the shaft to rotate. Spring means moves the piston in one linear direction to rotate the shaft in one direction. Fluid pressure moves the piston in an opposite direction to rotate the shaft in an opposite direction.
44 Citations
19 Claims
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1. A valve actuator for a valve comprising:
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a housing having a fluid pressure inlet, a fluid pressure exhaust, and an inner sealing shoulder; a rotatable screw shaft arranged in said housing connectable at one end to said valve; a ball bearing nut mounted on the other end of said shaft and forming a piston longitudinally movable in said housing from a first to a second position; biasing means surrounding said screw shaft engaging said piston and urging said piston to said first position thereof;
said piston containing peripheral seals for sealing engagement with the inner wall of said housing;
said piston sealingly engaging said inner sealing shoulder of said housing when said piston is in said second position thereof; andmeans connected to said piston engaging said housing to prevent rotation of said piston. - View Dependent Claims (2, 3)
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4. A valve actuator for a valve comprising:
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a housing having a fluid pressure inlet and a fluid pressure exhaust; a hydraulic motor arranged in said housing between said fluid pressure inlet and said fluid pressure exhaust and including a rotatable splined drive shaft; a rotatable screw shaft arranged in said housing connectable at one end to said valve; a ball bearing nut mounted on the other end of said screw shaft and forming plate means; connection means mounted on the other end of said screw shaft engageable with said motor drive shaft to rotate said screw shaft upon rotation of said motor shaft;
said plate means being movable along said screw shaft from a first to a second position upon rotation of said screw shaft in one direction;biasing means engaging said plate means and urging said plate means to said first position thereof; means for sealingly engaging said plate means when said plate means is in said second position thereof to prevent flow of fluid to said fluid exhaust; said drive shaft engaging said connector means upon application of fluid pressure to said hydraulic motor; and means for disengaging said drive shaft from said connection means upon release of fluid pressure from said hydraulic motor. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A valve actuator as recited in comprises spaced-apart 7 wherein said spring means comprisesspaced-apart spring fingers;
- and including means for sealing off the space between said hydraulic motor and the inner wall of said housing.
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11. A valve actuator for a failsafe valve comprising:
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a housing having a fluid pressure inlet and a fluid pressure exhaust; motor means arranged in said housing; a rotatable splined drive shaft connected to and rotated by said motor means; a rotatable screw shaft arranged in said housing and connectable to said valve; a plate means connected to and movable along said screw shaft upon rotation of said screw shaft; connection means mounted on said screw shaft and engageable with said drive shaft to rotate said screw shaft upon rotation of said drive shaft;
said plate means being movable along said screw shaft from a first to a second position upon rotation of said screw shaft in one direction;biasing means engaging said plate means and urging said plate means to said first position thereof; means in said housing and means on said plate means cooperating to seal off said fluid pressure exhaust to prevent flow of fluid therefrom when said plate means is in said second position thereof; said drive shaft engaging said connector means upon application of fluid pressure to said motor means; and means for disengaging said drive shaft from said connection means upon release of fluid pressure from said hydraulic motor.
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12. A valve actuator for a valve comprising:
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a housing having a fluid pressure inlet, a fluid pressure exhaust, an inner shoulder, and an inner bowl; a hydraulic motor arranged in said housing between said fluid pressure inlet and said fluid pressure exhaust and including a rotatable splined drive shaft; a rotatable screw shaft arranged in said housing connectable at one end to said valve; a ball bearing nut mounted on the other end of said screw shaft and forming plate means; a splined collar mounted on the other end of said screw shaft and engagable with said splined drive shaft; said plate means being longitudinally movable along said screw shaft from a first to a second position upon rotation of said screw shaft in one direction; biasing means surrounding said screw shaft and said bowl and engaging said plate means and urging said plate means to said first position thereof;
said plate means sealingly engaging said inner shoulder and said inner bowl when said plate means is in said scond position thereof;said splined drive shaft engaging said splined collar upon application of fluid pressure to said hydraulic motor; and means for disengaging said splined drive shaft from said splined collar upon release of fluid pressure from said hydraulic motor. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification