Apparatus for detecting the local temperature variations of an object and the sites of the temperature variations

An apparatus for detecting a site of a temperature variation in an object, comprising:

• an elongate temperature-sensing member including two elongate conductors constituting a signal transmission circuit, an insulating core in which one of said conductors is disposed, a band-shaped elongate amorphous magnetic alloy element mainly consisting of a ferromagnetic transition metal, having a prescribed Curie temperature corresponding to the lower limit of an anticipated abnormal temperature range, and disposed on said insulating core to extend therealong, and an elongate insulating layer disposed on said amorphous magnetic alloy element and said insulating core to cover them, the other of said conductors being wound about said insulating layer;
• a shielding member for electromagnetically shielding said temperature-sensing member;
• a pulse generator for supplying a pulse signal to one end of said temperature-sensing member;
• a pulse time difference detector for detecting a time difference between a point of time at which a pulse signal is received from said pulse generator at said one end of said temperature-sensing member and a point of time at which the pulse signal reflected from a site of said temperature-sensing member, where the characteristic impedance of said temperature-sensing member has changed due to an increase in temperature above the Curie temperature, is received at said one end of said temperature-sensing member;
• and
• a temperature variation site detector responsive to said pulse time difference detector for determining the site of temperature variation from the detected pulse time difference.