Westinghouse Electric Corporation

Thomas L Schuchart

David B Berrong

Gilbert F Hyde

Frank J Heymann

A valve plug assembly for use in a steam throttle valve includes a valve body and a removable guide ring attached to one end of the valve body. An outer edge portion is removed from the guide ring at the interface with the valve body so that a circumferential groove is defined about the valve plug when the guide ring is assembled to the valve body. A slot is formed in one wall of the groove, preferably in the guide ring, and a wear ring inserted in the slot. The wear ring extends above the wall surface and terminates in an angled bearing surface. A pressure seal ring is formed with a mating bearing surface and is placed in the groove prior to assembly of the valve plug. The angular taper on the mating bearing surfaces causes some retraction of the pressure seal ring in response to sudden valve plug movement in the closed direction.

Aligning and seal ring retracting apparatus for plug type valve

A valve plug having a valve plug housing shaped to fit in a bonnet cylinder of steam control valves has a pressure seal ring groove for holding a pressure seal ring therein. The pressure seal ring groove has a pair of walls and a bottom surface end and antiwedging relief groove formed in one wall of the pressure seal ring groove adjacent the bottom surface thereof to prevent the wedging of a pressure seal ring between a valve plug and a bonnet cylinder bore wall. The pressure seal ring wears a step in the contact surface to allow the wedging which can otherwise prevent the valve from closing as required for turbine overspeed protection. The valve plug housing pressure seal ring groove can be annular groove having an annular pressure seal ring therein and the relief groove can be annular groove formed in one wall of the pressure seal ring groove adjacent the pressure seal ring along the seal ring contact surface of the pressure seal ring. The relief groove has a pair of sidewalls and a bottom surface with one wall forming an extension to the pressure seal ring groove bottom surface so that wear on the pressure seal ring groove wall enlarges the width of the pressure seal groove to prevent a step forming therein and wedging of the pressure seal ring between the valve plug and the bonnet cylinder bore.

Anti-wedging pressure seal ring apparatus

A steam flow control valve for controlling large fluid flow rates, the valve having a reduced response to vibrational excitations experienced during throttling. A valve stem extending outward from the valve body and connected in the valve to a valve plug is guided by a substantially rigid cylindrical bushing extending substantially through the valve body. The bushing has an inner surface for guiding movement of the valve stem and an outer surface for guiding movement of the valve plug. The plug includes an inner annular guide ring about an upper edge for sliding along the outer surface of the bushing and limiting transverse motion.

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Casselberry, FL, United States of America

Thomas L Schuchart