How to judge the quality of a thermocouple

After using a thermocouple for a period of time, it is certain that there will be wear and tear, and it may even be damaged. The quality of individual thermocouples is related to their external thermocouple wires (wires), but how to determine the quality of a thermocouple? Below is a brief introduction on how to determine the quality of a thermocouple:

At the beginning, it can be determined whether the surface of the thermocouple wire is good or bad through process testing.

Thread the thermocouple wire to be tested into the common ceramic sleeve of the thermocouple, and place it together with the scale platinum rhodium thermocouple into a tube type electric furnace. Pull out the hot end from a cylindrical body made of porous nickel metal used for uniform heating in the tube type electric furnace. Place the cold ends of each compensating wire into a zero degree Celsius container held by a mixture of ice and water.

Maintain the tube furnace at the lowest temperature allowed by the thermocouple and firmly adhere to this range. At this time, use a Huiseiden potential difference meter that has passed the inspection to measure the thermoelectric potential difference between the scale thermocouple and the thermocouple to be tested, and record it.

According to the recorded thermoelectric potential difference, check the calibration table to find out the corresponding temperature of each thermocouple. If the thermocouple to be tested exceeds the tolerance, it can be determined as a divergent lattice.