| 摘要 |
PURPOSE:To obtain a sheath thermocouple whose fixing operation is comparatively easy and having good sealability by providing a thermocouple in a protecting tube consisting of a sealing alloy through an insultor, and forming the sheath thermocouple. CONSTITUTION:A chormel-alumel thermocouple is inserted into a protecting tube consisting of a sealing alloy e.g. 50wt% Ni-Fe to fill an insulator e.g. magnesia type ceramics. The diameter of the protecting tube is decreased to a desired value by surface decrease working, and further the protecting tube is cut down to the desired length. Respective wires of the thermocouple are connected at the another cut end, where the protecting tube is sealed airtightly to form a pre-oxide film on the surface of the protecting tube in a moist hydrogen furnace. |
