After the thermocouple is used for a period of time, the temperature will gradually decrease. Thermocouples used in non-corrosive atmospheres below 600°C are generally required to be verified once a year; Thermocouples used above 600°C or in highly corrosive atmospheres are required to be verified every six months. When the temperature measurement error exceeds 1%, it should be discontinued.
When a thermocouple is used to measure the temperature of a place, generally speaking, the actual temperature value of the measured place can be measured after a period of time; However, in fact, there is a heat conduction and heat exchange between the measured space, the measured object and the outside world, and the test temperature often has a certain deviation from the actual temperature. In order to reduce or eliminate this error, the following measures should be taken:
1) Reduce the emissivity of the thermocouple protection tube.
2) Increase the circulation of the medium to be measured.
3) Reduce the outer diameter of the thermocouple protection tube as much as possible.
4) Increase the insertion depth of the thermocouple.
5) Pay attention to the good insulation between the thermoelectrodes and the earth to reduce the thermoelectric potential loss.
6) Try to avoid the contamination of thermocouples, eliminate all kinds of external influences as much as possible, and reduce additional errors.