| 摘要 |
PURPOSE:To fix tightly an electrode and to prevent a measuring pipe made of ceramic from damaging by baking the measuring pipe while an electrode hole is bored in the measuring pipe and inserting and fixing an electrode rod which is cooled to extremely low temperature in the electrode hole. CONSTITUTION:The electrode hole 2b is bored in the unbaked measuring pipe 2 made of ceramic and then the pipe is baked without putting the electrode rod in the electrode hole 2b. Then, the electrode rod 4 which is cooled in a cryogenic atmosphere and reduced in diameter is inserted into the electrode hole 2b of this measuring pipe 2. Then, the electrode rod 4 is left at the room temperature to expand in diameter, so that the rod is fixed tightly in the electrode hole 2b. Consequently, the electrode rod 4 is fixed extremely tightly to improve its water-tightness. The measuring pipe 3 is baked before the electrode rod 4 is inserted, so an inexpensive material is usable for the electrode rod 4 and no stress is concentrated on part of the measuring pipe 2.
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