PURPOSE: To cope with the increase of the temperature of the wide range part of a combustion chamber wall by means of one heat-sensitive element by a method wherein the heat-sensitive element comprises a low melt point metallic wire and a protection tube for covering the metallic wire formed of a material having a heat resisting temperature higher than that of the metallic wire and having electric insulating property.
CONSTITUTION: A heat-sensitive element 15 comprises a metallic wire 24 having a heat-sensitive part 15A wound around the outer wall of a casing 1 and having a low melt point, and a protection tube 25 for covering the metallic wire formed of a material having a melt point higher than that of the metallic wire 24 and having electric insulating property. When the casing 1 is overheated, a hole is overheated to form a hole, and combustion gas leaks therethrough, the some part, heated to a highmost temperature, of the metallic wire 24 of the heat-sensitive element 15 is fused to stop combustion at a burner 3. This constitution enables detection of the abnormal temperature of the wide range part of the outer wall of the casing 1 and ensures enough safety.
YAJIMA TAKUYUKI
SAITO MASAHIKO
