F22B37/00—Component parts or details of steam boilers
F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
F22B37/42—Applications, arrangements or dispositions of alarm or automatic safety devices
F22B37/47—Applications, arrangements or dispositions of alarm or automatic safety devices responsive to abnormal temperature, e.g. actuated by fusible plugs