Thermocouple is a kind of temperature sensor, it is smaller than the diameter of a prefabricated thermocouple, flexible, good vibration resistance, suitable for installation in the case of prefabricated thermocouple can't install, I WRNK series thermocouple used to introduce thermocouple temperature measuring element, therefore, is accurate, sensitive, quick thermal response time, stable quality, long service life, etc. 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 transmitter, often and digital display table, recording instrument and electronic regulator, at the same time can also be as prefabricated thermocouple temperature sensing element. It can be directly measured in the production of chian from 0 ~ 800 ℃ in the scope of liquid, steam and gas medium, as well as the temperature of the solid surface. The working principle of thermocouple are two different components of conductor on both ends of the welding and form a loop, directly measuring WenDuan call work side, the terminal end is called the cold end, also known as the reference. When work end and reference end there is temperature difference, will produce thermal current in the circuit, connected to display instrument, the instrument will indicate the thermocouple thermoelectric emf generated by the corresponding temperature value. The thermocouple thermoelectric emfs growth over the course of measuring the temperature, the size of the thermoelectric emfs and thermocouple temperature difference on both ends of the conductor material and, only has nothing to do with hot electrode length and diameter. The structure principle of thermocouple is consists of a conductor, high insulation magnesium oxide, coat 1 cr18ni9ti stainless steel protecting tube, after many integrated control. Thermocouple products are mainly composed of terminal block, terminal and thermocouple basic structure, and with various mounting device. Thermocouple insulation type and hull type two kinds.