| 摘要 |
PURPOSE:To improve the sensitive characteristic of a temperature detection element and display the process of extraction with precision, by providing a thermistor, to be the temperature detection element, in parallel with the longitudial direction of a water introduction pipe, and covering its outside portion with a heat contraction tube. CONSTITUTION:A thermistor 13 of a temperature detection element 12 is installed in a water introduction pipe 8, and its outer portion is covered with a heat contraction tube 14, and is constituted by contracting the tube 14 through heating, so a space between the thermistor 13 and the tube 14 is small. The temperature detection element 12 is provided in parallel with the longitudial direction of the water introduction pipe 8, and fitted by means of a seal material 15 formed out of rubber. A temperature detection circuit 16 receives the output of the element 12, and compares it with a set reference value, and in the case of its voltage being higher than the reference value, the output of a comparator becomes low, and a display light is lighted. The lighting of the display light 18 continues while the temperature of the element 12 is high, and when the temperature lowers, voltage at an A point becomes lower than the reference value, and the output of the comparator 17 becomes of a high level, and the display light 18 is turned off. |
