It is widely used in production. Thermocouple has become one of the most commonly used temperature detection elements in industry. It has the characteristics of high measurement accuracy, wide measurement range, simple structure and convenient use. We understand and analyze products through various channels, and present a wide range of industry knowledge for netizens.
So next, let's understand the judgment of thermocouple?
The basic principle of thermocouple temperature measurement is that two different components of material conductors form a closed circuit. When there is a temperature gradient at both ends, there will be current passing through the circuit. At this time, there will be electromotive force - thermoelectric electromotive force between the two ends, which is the so-called Seebeck effect. Two kinds of homogeneous conductors with different components are thermoelectric poles, the one with higher temperature is the working end, the one with lower temperature is the free end, and the free end is usually at a constant temperature.
After using thermocouple for a period of time, there must be wear or even damage. Generally, the quality of thermocouple is related to the thermocouple wire (wire) in it. However, how to judge the quality of thermocouple wire is discussed briefly.




First of all, make sure that the appearance of thermocouple wire is no problem, good or bad, which can be determined only through inspection.




Put the thermocouple wire to be tested into the porcelain bushing dedicated to thermocouple, put it into the tubular electric furnace together with the standard platinum rhodium thermocouple, and insert the hot end into a porous cylinder made of metal nickel for soaking in the tubular electric furnace. Place the cold ends of the respective compensating leads in a container at zero degrees Celsius maintained by a mixture of ice and water.




Keep the tube furnace at the maximum allowable temperature of the thermocouple, and keep this range stably. At this time, use the qualified Wheatstone potentiometer to measure the thermoelectric potential difference generated by the standard thermocouple and the thermocouple to be tested and record it. According to the recorded thermoelectric potential difference, check the graduation table to find out the corresponding temperature. If the thermocouple to be measured is out of tolerance, it can be determined as unqualified.
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