The thermocouple is a commonly used temperature-measuring instrument. It directly measures the temperature, and converts the temperature signal into a thermal electromotive force signal, and converts it into the temperature of the measured medium through an electrical instrument (secondary instrument). The basic structure of thermocouples is roughly the same, usually composed of main parts such as thermal electrodes, insulating sleeve protection tubes and junction boxes, and used in conjunction with display instruments, recording instruments and electronic regulators.
Temperature is one of the important parameters that need to be measured and controlled in the industrial production process, In temperature measurement, thermocouples are widely used because of their simple structure, convenient manufacture, wide measurement range, high precision, small inertia, and easy remote transmission of output signals. In addition, because the thermocouple is a passive sensor, it does not need an external power supply for measurement, and it is very convenient to use, so it is often used to measure the temperature of gas or liquid in the furnace and pipeline, and the surface temperature of the solid.
There are eight types of thermocouples: S, R, B, N, K, E, J, and T. Among them, R, B, and S are composed of precious metals, and the wire diameter is thin. K, T, E, and N are ordinary metals with thick wire diameters. Commonly used thermocouples can be divided into two categories: standard thermocouples and non-standard thermocouples. 300mm to 1000 mm K-type thermocouples are provided on SISCO.com, which can measure the temperature from 0 to 1000℃.
Thermocouples are one of the most commonly used temperature-sensing elements in the industry. Its characteristics are:
- High measurement accuracy. Because the thermocouple is in direct contact with the measured object, it is not affected by the intermediate medium.
- Wide measurement range. Common thermocouples can measure continuously from -50 to +1600°C, and some special thermocouples can measure as low as -269°C and as high as +2800°C.
- Simple structure and convenience. Thermocouples are usually composed of two different metal wires and are not limited by size and opening. There is a protective sleeve outside, which is very convenient to use.