Anhui Tiankang provides you with a solution for thermocouple instability

Most of them are used for temperature measurement, which is essential in many industrial productions. However, many people still lack knowledge of using thermocouples, so below we will introduce this knowledge in detail.

For thermocouples used as benchmarks and standards, annealing is performed after each graduation point during graduation. For precious metal thermocouples, annealing procedures are crucial. According to the calibration regulations for standard thermocouples, they must be cleaned and annealed before calibration to eliminate contamination and stress, thereby improving the metallographic structure of the thermocouple wire material and enhancing measurement stability.

During the production and processing of thermocouples, the thermocouple wire is always contaminated on its surface after multiple rounds of diameter reduction and stretching. Meanwhile, from the perspective of the internal structure of the silk. Stress and lattice inhomogeneity are inevitable. The inconsistency of these physical states has an impact on the Seebeck coefficient of the dual wire and affects the instability of the thermocouple readings. So, a thermocouple that fails annealing cannot be used for accurate temperature measurement.

The stress introduced by quenching or cold processing can be basically eliminated by annealing. The indication error caused by annealing failure can vary from a few tenths of a degree to several degrees. It is related to the temperature to be measured and the magnitude of the temperature gradient on the thermocouple electrode. Low cost metal thermocouple wires are usually delivered for use in an "annealed" state. If high-temperature low-cost metal thermocouples need to be annealed, the annealing temperature should be higher than the upper limit of the operating temperature, and the insertion depth should also be greater than the actual operating depth.

The above analysis of the reasons for the instability of thermocouples and the various impacts that may result from it shows that the interference of electrical characteristics on thermocouples is particularly important. Only by maintaining stability can the normal use of products be ensured, which is a quality issue that must be taken into account.