PURPOSE: To increase the assurance, noise-resistant property and safety for detection of the temperature, by using the light signal which is made to pass through the optical fiber for both transmission and send-back purposes and at the same time utilizing the magnetic properties of the temperature-sensitive ferrite.
CONSTITUTION: The temperature-sensitive ferrite 3 is lower than the Curie point Tc°C when the temperature T of the sensor part D is lower than the set temperature Tc. Thus the ferrite 3 has a magnetic property to attract the lever 5, as a result, the follower piece 4 is under the lowered light transmission state 4a. Accordingly, the output light of the sensor part, i.e., the output light of the send-back device E is intensive, and the face that the temperature at the sensor part is not higher than the set level is decided automatically via the deciding device F. On the other hand, the ferrite 3 loses the magnetic property when the temperature T is higher than the temperature Tc. Thus the piece 4 is put under the light shielded state 4b, and the fact that the temperature of the sensor part D exceeds the set level is decided by the device F. In such way, the assurance, noise-resistant property and safety can be increased for detection of the temperature.
GAKOU NOBUKATSU
SUZUKI CHIYUUJI
