| 摘要 |
PROBLEM TO BE SOLVED: To obtain a thermocouple protection tube which uses Pt only for a necessary part, makes Pt not fall by bringing it into contact with a ceramic- made protection tube, and enables ceramic and fused glass to completely be cut off. SOLUTION: The top surface of necessary length of the ceramic-made protection tube is thermally processed at 1,200 to 1,500 deg.C after shot peening, and an outer peripheral surface having a gap with the opening part of a one-end closed Pt cap to be placed covering its top surface is coated with a Pt as an undercoating; and the ceramic-made protection tube is covered with the Pt cap, the opening part of the Pt cap is drawn inward to press the coating Pt film against the ceramic-made protection tube, and the drawn part and its periphery are wound with a PT wire and then coated with Pt. The whole protection tube is thermally processed at 1,200 to 1,500 deg.C to bring the ceramic-made protection tube, Pt, and PT cap into contact in one body.
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