Thermocouple used usually and display meter, recording meter, electronic computer and other systems. Directly measuring the range of 0 ℃ ~ 1300 ℃ in the process of producing all kinds of liquid, steam and gas medium, as well as in solid surface temperature. Characteristics of the thermal response time less, reduce the dynamic error; Flexible installation; Measuring range is large; High mechanical strength, good compression performance; The working principle of thermocouple electrode is composed of two different conductor material. When measuring the temperature difference is with the reference, the can produce thermoelectric power, the instrument will show thermoelectric potential corresponding temperature value. Explosion-proof thermocouple used usually and display meter, recording meter, electronic computer and other systems. Directly measuring the production site exist hydrocarbon explosives range of 0 ℃ ~ 1300 ℃ liquid, steam and gas medium, as well as solid surface temperature. Characteristics: a variety of explosion-proof, explosion-proof performance is good; Compression spring type thermal components, ant-vibration performance is good. Measuring range is large; High mechanical strength, good compression performance; Work principle of flameproof thermocouple flame-proof principle is to use the clearance, design has enough strength of the junction box, and other components, all which sparks, solitary and dangerous temperature parts are sealed in the junction box, thermocouple has to bend when an explosion inside the box, heat resistance to high pressure, fast response time and strong and durable many advantages, such as it and industrial use, as measure temperature sensor, and usually display meter, recording meter and electronic regulator, at the same time, also can be used as a temperature sensing element. It can directly measure all kinds of production process from 0 ℃ ~ 800 ℃ in the scope of liquid, steam and gas medium, as well as the surface temperature of the solid. And compared to the thermocouple is flexible, high pressure resistance, thermal response time is short and strong and durable, etc. Thermocouple as the temperature measurement sensor, usually with temperature transmitter, controller and display instrument, such as process control system, to directly measure or control in the production of a variety of 0 Fluid over a range of 1800 ℃, steam and gas medium and solid surface temperature. Thermocouple can bend, high pressure resistance, heat fast response time and strong and durable many advantages, such as it and industrial prefabricated thermocouple, as measure temperature sensor, and display meter, recording meter and electronic regulator usually used. Thermocouple temperature measurement principle is based on thermoelectric effect. Connect the two different conductor or semiconductor into closed loops, when the two contacts in temperature is not at the same time, the circuit will produce thermoelectric potential, this kind of phenomenon called the thermoelectric effect, also known as the seebeck effect.