Why do thermocouples need to be calibrated? How long is the verification cycle usually?

Any measuring instrument must be calibrated or calibrated according to relevant calibration regulations or standards before and during use. Thermistors, thermocouples, transmitters, etc. are all measuring instruments. If they are not calibrated, they may become inaccurate and affect the product. Some companies have scrapped their entire furnace of products due to inaccurate thermocouples, resulting in losses of several hundred thousand yuan.

If it is a new thermocouple, many manufacturers only conduct sampling inspection during the field calibration, which means that the qualification rate of the new thermocouple cannot be guaranteed to be 100%. Therefore, it is very necessary to calibrate the new thermocouple.

For thermocouples in use, long-term operation in high-temperature environments has a significant impact on their temperature measurement characteristics. Due to oxidation, corrosion, and other reasons, the properties of the material will gradually change, and the thermal characteristics will naturally change accordingly, resulting in inaccurate temperature measurement. Therefore, it is necessary to regularly calibrate thermocouples. For thermocouples that exceed the allowable error, they should be scrapped or their hot ends should be cut off and re welded, and then verified to be qualified before they can be used.

In theory, the calibration cycle for thermocouples is generally six months, and for secondary instruments it is usually 12 months. In special circumstances, it can be determined based on the usage conditions. The SPMK series thermocouple calibrator has fast temperature rise and fall, stable temperature control, small size, light weight, and easy portability. It is suitable for calibrating temperature instruments such as thermocouples, thermistors, temperature transmitters, and temperature switches in instrument workshops, measurement rooms, and calibration laboratories.