Emergency gas shut-off valve activated by fire

摘要

An emergency gas shut-off valve (1) has a tubular housing (2) with connectors (3,4) at each end, an inner seal (8) near the output end (4), and a widened centre-section (9) plug (34). The plug is closed by a spring (38) when this is released by the conversion of cold solid solder to a liquid state under conditions esp. of fire. The spring (38) is supported by a thrust bearing (17) in a groove (12) at one end near the inlet connector (3), and at the other end by the plug (34). The support (17) has a wedge-lock circumferential cross-piece above an inner ring. The inner ring also bears a guide bush (27) passing through the spring (38) for a guide bolt (33) linked to the plug (34).