thermocouple of structure requirements and precautions

In order to ensure the reliable and stable operation of thermocouple, it is necessary to ensure that its structure is reasonable. So, what requirements should the structure of thermocouple meet? First of all, the welding of the two thermoelectric poles must be firm; and the two thermoelectric poles should be well insulated from each other to prevent short circuit. In addition, the connection between compensation conductor and free end should be stable, reliable and convenient.

In addition, in the composition of thermocouple, the protective sleeve should be able to make the thermoelectric pole completely separate from the harmful medium. In fact, the product belongs to an energy converter, which converts thermal energy into electric energy and measures temperature with the generated thermoelectric potential.

It should be noted that in order to meet the application requirements, the thermoelectric potential of the thermocouple should be the difference of the temperature function between the two ends of the working end, rather than the function of the temperature difference between the cold end and the working end. In addition, pay attention to the thermal potential. Generally, when the structure of the material is uniform, the size of the thermoelectric potential is independent of the length and diameter, but only depends on the composition of the material and the temperature difference at both ends.

It should be noted that after the material composition of the two thermocouple wires is determined, one of the factors affecting the thermoelectric potential is the temperature difference. If the temperature of the cold end remains constant, the thermoelectric potential is only a single value function of the working temperature. At present, the product is mainly divided into two categories, one belongs to standard type, the other is non-standard type.

The so-called standard thermocouple mainly refers to the products produced in accordance with the relevant provisions. In this kind of products, the relationship between the thermoelectric potential and the temperature, the allowable error, etc. are in line with certain standards, and the thermocouple with a unified standard index table and its matching display instrument can be selected.