Multi-media safety relief valve

Abstract

A safety valve for relieving excessive pressure in a fluid system including a valve body having a central chamber, a discharge flow nozzle connected into the chamber having a valve seat on the end of the flow nozzle in the chamber, a valve disc movably mounted in the chamber for movement between a closed position on the nozzle seat and an open position spaced from the nozzle seat, a valve disc holder connected with the valve disc having a deflecting rim circumscribing the valve disc seat provided with an internal outwardly divergent annular deflecting surface, a blowdown ring mounted on the nozzle having an inner ring portion provided with an outer frustoconical deflecting surface substantially parallel with and spaced from the valve disc holder deflecting surface, the blowdown ring including an outer cylindrical rim provided with circumferentially spaced semi-elliptical discharge ports and an internal cylindrical surface substantially parallel with and spaced from the outer cylindrical surface of the valve disc holder, and a spring connected with the valve disc holder for biasing the valve disc holder and valve disc closed. The blowdown ring is adjustable for changing the blowdown of the valve. The configuration of the valve disc holder and the blowdown ring deflecting surfaces provides chatter free operation.