| 摘要 |
PURPOSE:To prevent contamination of the optical system by an arrangement wherein the optical system is sealed up by the plane plate being electromagnetically displaced through the action of the solenoid or the like when detecting that the temperature of foods reaches a predetermined temperature. CONSTITUTION:Any substance with the temperature more than 0 deg.K radiates infrared energy and the quantity of this energy has correlation with the temperature of the substance. Based on this principle, it is detected that the temperature of foods reaches to a predetermined temperature. Provided between foods 6 and an infrared sensor 15 is sealing means comprising a solenoid 20, a spring 21, a plane plate 22 and a supporter 23. Upon an input signal, the solenoid 20 is operated to overcome the force of the spring 21 and allow the plane plate 22 including a corresponding port to be moved in the direction of the arrow for closing a port 9 opened at the wall of the cooker. By so doing, the state which otherwise could cause the decisive damage to the optical system can be previously detected and then the port is sealed up, so that the optical system is held free from contamination. |
