Anti-wedging pressure seal ring apparatus

Abstract

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.

Dependencies are inferred from the claim text.