Abstract

A safety valve for fitting into a compressed gas cylinder to terminate gas flow from the cylinder when a primary gas valve attached to the cylinder port of the cylinder is deflected or severed. The safety valve is independently supported in the cylinder port below the location of the primary gas valve. A threaded housing having a channel for the passage of gas to and from the cylinder is threaded into the cylinder port below the location of the primary gas valve. A poppet seat is provided in the housing. A tubular portion of the threaded housing extends up and fits snugly into the gas passage of the primary gas valve. A cylindrical housing having apertures for the passage of gas is attached to the threaded housing. A poppet is provided in the cylindrical housing, which is biased into the poppet seat by a helical spring. The poppet is held off of the poppet seat by means of a frangible element. A relatively minor deflection, or shearing off, of the primary gas valve will be passed through to the frangible element, resulting in the breaking of the element and thereby allowing the poppet to seat in the poppet seat preventing the flow of gas from the cylinder to the primary gas valve. A polymer collar may be used in connection with the safety valve to eliminate thread leakage. A remote triggering device is set forth for seating the poppet in the poppet seat without a deflection or severing of the primary gas valve. Further, a flow restriction device for use with the safety valve is described.