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A rotary plug valve has hydraulically actuated seals for sealing between a valve body and a rotatable valve plug. The valve plug is rotated to open or close the valve. A valve handle for turning the plug can be rotatably uncoupled from the valve plug when the valve is closed and turned relative to the plug toward an overtravel position to actuate a hydraulic piston to pressurize the seals.SAFETY VALVES A second piston regulates pressure to the seals and prevents overpressurization. A rotary plug valve comprising:
a body having an inlet duct and an outlet duct; Ball Valvesa rotatable valve plug in the body having a port for fluid communication between the ducts, the valve having an open position where at least part of the port overlaps the ducts, and a closed position where no part of the port overlaps the ducts; means mounted on the plug for forming a pressurizable seal with the body; Plug Valves a fluid reservoir containing a hydraulic fluid and communicating with the pressurizable seal; a piston in the valve plug operatively communicating with the reservoir for applying pressure to the hydraulic fluid in the reservoir for pressurizing the seal; a handle for turning the valve plug from the open position to the closed position; means for rotatably coupling and uncoupling the handle with or from the valve plug, the handle being coupled with the valve plug when the valve is open, the handle being uncoupled from the valve plug when the valve is closed, the coupling means including a cam on the valve body, a locking pin, a cam follower on the locking pin, a passage in the handle for receiving the locking pin, a recess in the valve plug for engaging the locking pin, and means for urging the cam follower against the cam, whereby engagement of the cam follower with the cam causes the locking pin to selectively engage or disengage the recess in the valve plug, so that when the locking pin engages the recess, the handle is rotatably coupled with the valve plug, and when the locking pin is withdrawn from the recess and disengages the recess, the handle is rotatably uncoupled from the valve plug; means for preventing further rotation of the valve plug relative to the valve body when the handle is uncoupled from the valve plug; and actuating means for actuating the piston upon the rotation of the handle when the handle is rotatably uncoupled from the valve plug for pressurizing this seal. The rotary plug valve of this invention comprises a valve body having an inlet duct and an outlet duct, and a rotatable valve plug having a port for fluid communication between the ducts. The valve has an opened position where at least part of the port overlaps the ducts, and a closed position where no part of the port overlaps the ducts. Hydraulically actuated seal means are provided for selectively sealing between the plug and the valve body around the ducts in the closed position. A handle turns the valve plug from the opened position to the closed position and vice versa. A hydraulic fluid communicates between a reservoir and the hydraulically actuated seal means. A piston operatively communicates with the reservoir for applying pressure to the hydraulic fluid to pressurize the seal. Means are provided for rotatably coupling and uncoupling the handle with or from the valve plug. When the valve is opened, the handle is coupled with the valve plug. When the valve is closed, the handle is uncoupleable from the valve plug and can, while uncoupled, be rotated further toward an overtravel position. An actuating means is provided for actuating the piston by the handle between the start of the uncoupled rotation and the overtravel position for pressurizing the seal means.

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