MEASURING METHOD FOR TEMPERATURE ERROR OF THERMOCOUPLE

PURPOSE:To measure the temperature error of a thermocouple to be measured accurately by heating a standard thermocouple and the thermocouple to be measured in a heating atmosphere while their tip parts are inserted into a single cap made of a good thermal conductor. CONSTITUTION:The tip part of a standard thermocouple 1 is inserted into a hole 5 of a cap 4 and the tip part of a thermocouple 2 to be measured is also inserted into a hole 6 of the cap 4 before the both are charged in a heating furnace 3. Then, the electromotive forces that those couples 1 and 2 generate are made to operate on each other, and their difference is amplified and recorded to obtain a temperature difference. The cap 4 is made of metal, or a good thermal conductor, so those thermocouples 1 and 2 are heated approximately to the same temperature, eliminating a difference in heating temperature due to a position difference between the both. In addition, the temperature variation width of the cap surface due to variation in the quantity of radiation heat from the furnace wall by an electric heater 8 is less than that in the cap.