thermocouple of detection method

Thermocouple performance is good or bad, naturally need to be tested to know. However, before testing, it is necessary to check whether the appearance of the thermocouple is normal. Only if the appearance quality is qualified, it is necessary to continue the inspection. Usually, when testing, the thermocouple to be tested should be covered with a special porcelain bushing for thermocouple.

It should be noted that the prepared sample to be tested should be placed in the tubular furnace together with the standard thermocouple. At this time, the hot end should be inserted into the cylinder. After that, put the cold ends of the respective compensation wires into a zero degree centigrade container. Then maintain the temperature of the tubular furnace at the temperature allowed by the thermocouple, and then use the qualified Wheatstone potentiometer to measure the thermoelectric potential difference between the standard thermocouple and the thermocouple to be measured, and make records at the same time.

According to the above measured data to find out the corresponding temperature point. If the thermocouple is out of tolerance, it can be judged as unqualified. For unqualified thermocouple, a small section can be cut off from the hot end and welded again. The specific operation method is as follows: if it is a common nickel chromium thermocouple, the voltage can be reduced by using an autotransformer, and then two wires of the thermocouple are combined into one pole, and the other pole is made of carbon rod to directly ignite the arc. The two thermocouple wires will melt into a small ball on the head.

In the process of operation, we must pay attention to safety. Especially in the use of autotransformer, we must ensure its good insulation. For the welding of thermocouple, another method is adopted: first, insert one pole of the power supply after voltage regulation into sodium chloride solution, and the other pole is thermocouple. Clamp the thermocouple light point solution surface with insulating clamp to complete the welding.

Then we are testing the thermocouple to determine whether it is qualified or not.