ORIFICE PLATE SEAL RING FOR CONTROLLED CLOSURE CHECK VALVE

摘要

ORIFICE PLATE SEAL RING FOR CONTROLLED CLOSURE CHECK VALVE A check valve is comprised of a body having inlet and outlet passages and a cylindrical chamber within the body, the axis of which forms an angle with the axis of the inlet and outlet passages. An orifice plate in the cylindrical chamber divides the chamber into a dashpot chamber and a valve chamber which is in communication with the inlet and outlet passages. A valve seat in the valve chamber separates the inlet and outlet passages. A valve closure element is mounted for reciprocation in the valve chamber between a valve open position and a valve closed position where an element is seated upon the seat. A piston is mounted for reciprocation in the dashpot chamber. A piston rod extends through an opening in the orifice plate and connects the closure element and the piston. Means are provided to apply the pressure in the outlet passage to the piston to urge the piston and closure element toward valve closed position. At least two parallel bleed passages are provided through the orifice plate to allow the flow of fluid between the dashpot chamber and the valve chamber. A pressure energized sealing member is responsive to the pressure differential between the dashpot chamber and the valve chamber to close one of the bleed passages when the differential exceeds a predetermined amount.