Spring body excess flow valve

Claim 1

A safety excess flow shut off valve for a fluid delivery system, comprising: a hollow housing mounted in the fluid delivery system for defining a fluid flow passageway and a valve seat, said housing having an upstream end and a downstream end, said upstream end including an inlet for receiving upstream fluid from the fluid delivery system and said downstream end including an outlet for discharging the received fluid downstream in the fluid delivery system; an intermediate portion of the housing disposed between the outlet and the valve seat, the intermediate portion including a ledge at a downstream end; a valve body mounted within said fluid passageway for moving between an open position and a closed position to control excess fluid flow along said fluid passageway; said valve body having at least one by-pass channel for facilitating a small by-pass flow of fluid when said valve body is moved to said closed position blocking said fluid passageway; a spring mounted within said fluid passageway for holding said valve body in a normally opened position when the flow of fluid along said passageway is below a predetermined level and for compressing under a drag force created by said valve body as the flow of fluid along said passageway exceeds said predetermined level to allow said valve body to substantially seal the fluid passageway except for said small by-pass flow of fluid traveling along said channel, the spring extending from upstream of the valve seat through the fluid flow passageway surrounded by the valve seat and into the intermediate portion, the spring being supported at a downstream end by the annular ledge of the intermediate portion; and wherein said valve body includes: a hollow cylindrical seat body member having a closed upstream end to create a drag force in response to upstream fluid passing through said fluid flow passageway and an open downstream end including a cylindrical shaped skirt defining a spring receiving opening at the open downstream end of said body member and having a distal end portion, said cylindrical seat body member receiving an upstream end of the spring; wherein said skirt is configured to sealingly engage said valve seat to facilitate the blocking of said fluid flow passageway when said distal end portion of said skirt engages said seat; and a cylindrical upstream retaining member defining an annular ledge, said retaining member being inserted in the upstream end and said annular ledge cooperating with the hollow cylindrical seat body member to limit upstream movement of said seat body member.