| 摘要 |
PURPOSE:To obtain a noncontact type temperature monitoring system dispensing with leads or the like, by applying an alternating magnetic field to a sensor comparing magnetic bodies with the known Curie temperature having a fine gap arranged at a measuring section from the circumference to detect changes in the oscillation thereof caused. CONSTITUTION:An induction heating coil 2 is arranged on the circumference of a conductive body 1 to be heated and a high frequency current is fed to the coil 2 from a power source 3 to cause an induction heating of the body 1 being heated, the temperature of which is monitored with a sensor 4 arranged at a measuring section. The sensor 4 is provided with a cylindrical magnetic body 4a having the Curie temperature in the temperature range somewhat higher than a desired heating temperature with two fine gaps G in such a manner as to be housed in a non-magnetic case 4b. A high frequency current flows to the coil 2 to raise the temperature of the body 1 being heated while an alternating magnetic field is applied to the sensor 4 to cause a force between the two magnetic bodies 4a so that they vibrate at the frequency doubling the alternating magnetic field to generate a sound wave, which is detected with a sound wave detector 5. When the temperature of the measuring section is below the Curie temperature, a tense sound wave is generated and as it reaches the Curie temperature, the sound wave becomes weak. This facilitates the judgment of a specified temperature. |
