FUSIBLE PLUG

Problem A conventional alloy for a fusible plug contained harmful elements such as Cd or Pb, so there was a concern of pollution by these harmful elements. The present invention provides a fusible plug which does not contain the harmful components Cd or Pb, with which the alloy is not forced out of the fusible plug even when used for long periods as a safety device for refrigeration equipment, and which has a high mechanical strength such as creep strength. Means for Solving the Problem A fusible plug is used which employs a fusible alloy consisting essentially of 0.1 - 2.0 mass percent of Sn, 31 - 37 mass percent of Bi, and a remainder of In, the alloy melting at approximately at 70- 75°C. A fusible plug is used which employs an alloy consisting essentially of 0.05 - 0.4 mass percent of Zn, 47 - 55 mass percent of Bi, and a remainder of In, the alloy melting at approximately 90 - 95°C.