THERMOCOUPLE WITH PROTECTIVE TUBE

摘要

PURPOSE:To permit reduction in amount of discharged gas within a vacuum vessel if a protective tube for a thermocouple with protective tube should be damaged, as well as checking of soundness of the protective tube due to the helium leak test by a method wherein the protective tube is provided at its intermediate part with a nozzle or a hole. CONSTITUTION:A strand 1 is electrically insulated from a protective tube 3 with a magnesium oxide 4 or the like. The protective tube 3 is provided at its intermediate part with a nozzle 7 or a hole 7' through a fitting 5. On the tail end side of the protective tube 3, the strand 1 is connected with a compensation lead 6 at the part of an adapter 8. In the event the protective tube 3 is damaged and gas absorbed in the magnesium oxide 4 or the like is discharged into a vacuum vessel, an amount of gas discharged into the vacuum vessel can be reduced by evacuating the interior of the protective tube 3 with a vacuum evacuator through a vacuum-resistant rubber hole, etc.