| 摘要 |
PROBLEM TO BE SOLVED: To detect abnormal temperature of an object to be measured easily through a simple structure and to detect the position in the object where the temperature has risen. SOLUTION: A light source 2 and a light receiving element 2 are connected through an optical fiber 3 with a photocoupler 4 which is connected with first through fourth temperature sensors 6a, 6b, 6c, 6d through an optical fiber 7. Each temperature sensor 6a, 6b, 6c, 6d comprises a case having one open end, a waterproof cap having a central through hole inserted into the case through the opening, and a temperature sensitive part where the inner space of case defined by the waterproof cap is filled with a temperature sensitive color- changing member made of similar material which changes its color to a color of which light absorption and scattering are easily changeable to a light having a specified wavelength upon temperature rise. Forward end face of the optical fiber 7 in each temperature sensor 6a, 6b, 6c, 6d is spaced apart by a different distance from the surface of temperature sensitive color changing member at each tamperature sensitive part. |
