Nozzle check valve

Abstract

A nozzle check valve comprises a valve body () and a nozzle () centrally arranged within the upstream end of valve body (), a fluid channel () is defined by the outer face of the nozzle () and the inner face of the valve body (). A guide bush () is mounted on a nozzle axial extension () and an annular disc () comprising a disc sealing ring () connected to a central barrel () by a plurality of webs () is mounted on the guide bush () for axial movement of the annular disc () relative to the valve body to open and close the fluid channel (). A spacer () is arranged on the nozzle axial extension () downstream of the guide bush () and a diffuser () is arranged on the downstream side of the spacer (). A spring () between the annular disc () and the diffuser () urges the disc towards the valve closed position. The stroke of the valve, the maximum movement of the annular disc () from the valve closed position to the valve open position where the annular disc () is in contact with the upstream face of the diffuser (), is determined by the axial length of the spacer (). The centre of mass of the annular disc () is located along the central axis of the disc () at an axial position where the barrel () is in sliding contact with the guide bush ().