Abstract: An improved check valve has an operating chamber with a disc disposed therein which is capable of axial movement from a closed position against a valve seat to an opened position to prevent feedwater from flowing from the normal outlet to the normal inlet of the valve. A cylindrical member extends upwardly from the disc through a fixedly mounted baffle plate which generally separates an upper portion of the operating chamber from the lower portion. A piston is mounted on an extended end of the cylindrical member to generally define a dashpot chamber between the piston and the baffle plate. The dashpot chamber entraps a greater volume of feedwater when the valve is open than when closed to limit valve closure rate by limiting the rate at which feedwater leaves the dashpot chamber during closure.

Abstract: An improved bi-directional pressure balanced valve includes a deflecting device at the axial opening in the closure disc to prevent an over balancing of the main valve disc assembly when fluid flow from the first flow passage impinges on the axial opening during closure of the valve. The preferred deflecting device includes a circular deflector plate which is mounted on the main disc to be centrally aligned with the axial opening and perpendicular thereto and having a diameter substantially larger than the diameter of the axial opening. The deflector plate is parallel with the lower surface of the main disc and it is separated therefrom to require fluid entering the axial opening to first flow between the lower surface and the deflector plate.

Abstract: A flow passage providing improved pressure recovery in a valve having an axially movable closure element which includes the provision of an annular diffuser flow passage from the seat port to the periphery of the closure member to reduce the fluid pressure drop across the valve when the closure member is moved a limited distance to its fully open position. The annular diffuser flow passage is provided between a pair of oppositely disposed frusto-conical surfaces respectively provided on the valve body and the closure element. The closure member may also be provided with a convexly shaped projection and the valve flow passage shaped to further reduce the pressure drop across the valve.