What is a thermocouple thermometer generally suitable for measuring?

Abstract: What is a thermocouple thermometer generally suitable for measuring? Thermocouple thermometer is a widely used temperature measuring device in industrial production. Thermocouple sensor is composed of two metal wires of different materials, which has the advantages of simple structure, convenient use, high precision, wide range and vibration resistance, and is suitable for medium and high temperature areas. Let's look at the working principle of thermocouple thermometer! Thermocouple thermometer Thermocouple thermometer working principle What is a thermocouple thermometer generally suitable for measuring?

Thermocouple thermometer is a temperature measuring instrument based on thermoelectric effect. It has the advantages of simple structure, wide measuring range, convenient use, accurate and reliable temperature measurement, convenient remote signal transmission, automatic recording and centralized control, etc., and is widely used in industrial production.

Working principle of thermocouple thermometer

Two conductors with different compositions (called thermocouple wires or hot electrodes) are connected at both ends to form a loop. When the junction temperature is different, electromotive force will be generated in the loop. This phenomenon is called thermoelectric effect, and this electromotive force is called thermoelectric potential. Thermocouple uses this principle to measure temperature, in which one end directly used to measure the temperature of medium is called working end (also called measuring end) and the other end is called cold end (also called compensation end); The cold end is connected with a display instrument or a supporting instrument, and the display instrument will point out the thermoelectric potential generated by the thermocouple.

Thermocouple is actually an energy converter, which converts thermal energy into electrical energy and uses the generated thermoelectric potential to measure temperature. For the thermoelectric potential of thermocouple, we should pay attention to the following issues:

1. Thermoelectric potential of thermocouple is the difference of temperature function at both ends of thermocouple working end, not the difference of temperature function at both ends of thermocouple cold end and working end;

2. When the thermocouple material is uniform, the thermoelectric potential generated by the thermocouple has nothing to do with the length and diameter of the thermocouple, but only with the composition of the thermocouple material and the temperature difference between the two ends;

3. When the material composition of two thermocouple wires is determined, the thermoelectric potential of thermocouple is only related to the temperature difference of thermocouple; If the temperature at the cold end of the thermocouple remains unchanged, the thermoelectric potential of the thermocouple is only a single-valued function of the temperature at the working end. Weld two conductors or semiconductors A and B of different materials into a closed loop, as shown in the figure. When there is a temperature difference between the two persistent points 1 and 2 of conductors A and B, electromotive force will be generated between them, thus forming a certain amount of current in the loop. This phenomenon is called thermoelectric effect. Thermocouples work by this effect.

What is a thermocouple thermometer generally suitable for measuring?

The integrated temperature transmission mode of bimetal thermometer, thermocouple or thermal resistor is adopted, which not only meets the requirements of on-site temperature measurement, but also meets the requirements of long-distance transmission, and can directly measure the temperature of liquid, vapor, gas medium and solid surface in the range of -80-+500℃ in various production processes.

Usage: It is used to measure various temperature objects, and the measuring range is extremely large, far larger than that of alcohol and mercury thermometers.

It is suitable for high-temperature areas such as steelmaking furnaces and coking furnaces, and can also measure low-temperature objects such as liquid hydrogen and liquid nitrogen.