In our petroleum, electric power, chemical and other important departments, the application of thermocouple compensation wire has been very common. What is thermocouple compensation wire? Thermocouple compensation wire is used to extend the thermoelectric pole, that is, to move the cold end of the thermocouple, and connect with the display instrument to form a temperature measurement system. Now let's understand the five points that should be paid attention to in the use of thermocouple compensation wire.

Five points for attention in the use of thermocouple compensation wire

I. selection of compensation wire

The compensation wire must be selected correctly according to the type of thermocouple used and the occasion used. For example, the compensation wire of K-type couple should be selected, and the operating temperature range should be selected according to the application situation. Generally, the operating temperature of KX is 0-1200 ℃, and the wide range is 0-1300 ℃. The error of common level is ± 2.5 ℃, and that of precision level is ± 1.5 ℃.

II. Contact connection

The two contacts at the thermocouple terminal shall be as close as possible, and the temperature of the two contacts shall be the same as possible. The temperature at the connection with the instrument terminal shall be the same as possible. Where there is a fan in the instrument cabinet, the contact shall be protected to prevent the fan from blowing directly to the contact.

III. service length

Because the signal of the thermocouple is very low, it is microvolt level. If the distance used is too long, the signal attenuation and the interference of strong electricity in the environment are coupled, it can make the signal of the thermocouple distorted, resulting in inaccurate measurement and control of temperature, and temperature fluctuation will occur when the control is serious.

According to our experience, it is usually better to control the length of thermocouple compensation wire within 15 meters. If it is more than 15 meters, it is recommended to use a temperature transmitter to transmit signals. Temperature transmitter is to convert the potential value corresponding to the temperature into DC current for transmission, with strong anti-interference.

Four, wiring

The wiring of compensation wire must be far away from power line and interference source. In places where crossing cannot be avoided, cross mode should also be adopted as much as possible, rather than parallel.

V. shield compensation wire

In order to improve the anti-interference of thermocouple connecting wire, shielded compensating wire can be used. The effect is better for the situation with more interference sources. However, the shielding layer must be strictly grounded, otherwise, the shielding layer will not play the role of shielding, but enhance the interference.

The above contents are the five items that should be paid attention to in the use of thermocouple compensation wire. Because of its excellent acid resistance, alkali resistance, wear resistance and non flame retardancy, the thermocouple compensation wire can be immersed in oil and water for medium and long term use. Therefore, the thermocouple compensation wire has been concerned and applied by many industries.