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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 u

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.

대표청구항 ▼

An improved check valve of the type having a valve body with a passage therethrough intersected by an operating chamber terminating at the passage with a valve seat and a disc movable in the chamber toward a closed position engaging the valve seat by fluid flow forces in one direction and an open po

An improved check valve of the type having a valve body with a passage therethrough intersected by an operating chamber terminating at the passage with a valve seat and a disc movable in the chamber toward a closed position engaging the valve seat by fluid flow forces in one direction and an open position spaced therefrom by fluid flow forces in the other direction, the improvement comprising: a cylindrical member connected at one end to the disc and at the other end to a piston having a peripheral surface adjacent the interior surface of the operating chamber and defining thereabove an upper chamber; a baffle plate in the operating chamber axially between said piston and said disc and surrounding said cylindrical member at an axial opening whereby said piston, said baffle means, said interior surface and cylindrical member define therebetween a dashpot chamber having a predetermined volume of liquid therein in the open position; means for limiting the rate at which liquid leaves the dashpot chamber as the disc moves from said open position to the closed position and thereby the closing rate of said disc; and conduit means fluidly communicating the upper chamber with the passage at a location upstream of the valve seat when the flow is in said one direction, said conduit means establishing a pressure balance between the upper chamber and said location providing an upward biasing on the piston for flow in said other direction and preventing fluid conditions in the upper chamber from retarding the closing rate for flow in said one direction whereby the closing rate is prescribed by the rate at which the liquid leaves the dashpot chamber.