Abstract: The thermocouple protecting tube of this invention is characterized by having a heat-insulating layer in an annular space formed by and between an inner ceramic tube and an outer silica glass tube which are concentrically disposed within each other. Due to the above construction, the protecting tube can withstand the thermal shock which it receives when immersed in a molten body of high temperature and accordingly the thermocouple enclosed in the protecting tube can continuously measure the temperature of molten steel for a considerable length of time.

Abstract: The thermocouple protecting tube of this invention is characterized by having a heat-insulating layer in an annular space formed by and between an inner ceramic tube and an outer silica glass tube which are concentrically disposed within each other. Due to the above construction, the protecting tube can withstand the thermal shock which it receives when immersed in a molten body of high temperature and accordingly the thermocouple enclosed in the protecting tube can continuously measure the temperature of molten steel for a considerable length of time.

Abstract: A thermocouple protecting tube substantially has a duplicate tube construction wherein the inner ceramic protecting tube which contains a thermocouple element is concentrically enclosed by an outer protecting pipe which is of high thermal shock resistance.