| 摘要 |
PURPOSE:To form the durable protecting tube, by surrounding the metal protecting tube by a porous ceramic tube which has chemical durability against the fused salt and includes nitride, boride, and carbide having reduction resistance. CONSTITUTION:A thermocouple 1 is inserted into the metal protecting tube 2 whose structure at the lower end is closed and which comprises iron, stainless steel nickel, Kanthal alloy, chromium, or the like. Said metal protecting tube 2 is further inserted into the porous ceramic tube 3 which includes 90wt% or more of at least one of nitride, boride, and carbide and has the structure whose lower end is closed so that the tube 3 surrounds the tube 2. The top of the metal protecting tube 2 and that of the porous ceramic tube 3 are fixed by a jig 4. Said protecting tube for measuring the temperature is inserted in the fused salt bath 8 and the measurement of the bath temperature is performed. |
