| 摘要 |
PURPOSE:To prevent a thermocouple from oxidizing and to improve its durability by sealing >=1 couple of thermocouple storage holes which are arranged in the lengthwise direction of an insulating protection pipe and coupled at the tip part of the protection tube with seals, and cutting off the outside air. CONSTITUTION:The protection tube 11 is formed of ceramic such as alumina and a couple of thermocouple storage holes 13 which are coupled on the tip side are formed therein. For example, an alumel wire and a chromel wire which constitute a thermocouple are stored in the storage holes 13, and their tip sides are joined together by soldering, etc., on the tip side of the protection tube 1 to form a temperature measuring junction. The end part of each of the storage holes 13 close to its end part is sealed with a seal 14 formed by filling a seal material such as glass and its inside is closed. Further, the junction 15 is also fixed with a similar seal material 19. Plural couples of thermocouples 12 can be put in the protection tube 1. Thus, no outside air enters the storage hole 13, so even if the junction 15 is held at high temperature, it is hardly oxidized and high heat resistance is secured. |
