Heat-operated safety valve for gas pipe

摘要

The heat-operated safety valve (1) has two end-fittings (2,3), the first of which forms a truncated cone valve seat (6). The valve housing has a valve (5) with a shoulder (8) translating into a longer truncated cone closing surface (7). The valve is held in the open position by a spigot (15) which is joined to a spring washer (13) by material (17) which melts at high temperatures. If the temperature increases beyond a pre-determined point, the material melts, releasing the spigot and the valve. A spring (14) closes the valve. The closing surface is directed to the valve seat by a guide (9). The two surfaces form a self-closing cone. The valve has a greater coefficient of expansion than the housing, holding the valve closed.