Patent ID: 7025327
Filing Date: 2006-04-11
Classification: F16K

Abstract:
1. A valve assembly comprising: a valve housing having an axis and defining an interior; a fluid provided in the valve housing and substantially filling the housing interior; a valve stem disposed in the housing interior; a piston attached to the valve stem, wherein the piston and valve stem are movable along the housing axis within the housing interior between first and second positions, wherein movement of the piston from the first position to the second position defines a closing stroke of the valve assembly; a valve actuation control device disposed in the housing interior, the valve actuation control device allowing the fluid to freely flow from one side of the piston to the other side during a first portion of the piston's movement between the first and second positions, such that the valve stem has a first velocity during the first portion of the piston's movement; and a force compensating assembly in fluid communication with the housing interior, the force compensating assembly regulating the flow of fluid from one side of the piston to the other side during a second portion of the piston's movement between the first and second positions, such that the valve stem has a second velocity slower than the first velocity during the second portion of the piston's movement.