Safety valve for compressed gas cylinders

摘要

The safety valve (10) fits into a compressed gas cylinder (12) to terminate gas flow from the cylinder (12) when a primary gas valve (14) attached to the cylinder port of the cylinder (12) is deflected or severed. The safety valve (10) is independently supported in the cylinder port below the location of the primary gas valve (14). A threaded housing (18) having a channel for the passage of gas to and from the cylinder (12) is threaded into the cylinder port below the location of the primary gas valve (14). A poppet seat is provided in the housing (18). A tubular portion (44) of the threaded housing (18) extends up and fits snugly into the gas passage of the primary gas valve (14). A cylindrical housing (24) having apertures (22) for the passage of gas is attached to the threaded housing (18). A poppet (26) is provided in the cylindrical housing (24), which is biased into the poppet seat by a helical spring (28). The poppet (26) is held off of the poppet seat by means of a frangible element (38). A relatively minor deflection, or shearing off, of the primary gas valve (14) will be passed through to the frangible element (38), resulting in the breaking of the element (38) and thereby allowing the poppet (26) to seat in the poppet seat preventing the flow of gas from the cylinder (12) to the primary gas valve (14). A polymer collar (46) may be used in connection with the safety valve (10) to eliminate thread leakage.