Industrial thermocouple is a component composed of one or more pairs of hot electrodes and insulators, used to prevent short circuits between hot electrodes and (or) between hot electrodes and protective tubes, and protect the hot electrode components from environmental damage. If the affected tube is correctly connected to the thermocouple used, move the reference end of the thermocouple to the output end of the pair of wires. When there is a step change in temperature, the time required for the output of the thermocouple to change to a certain percentage of the step change, usually expressed as τ.
Commonly used general industrial thermocouple
1, platinum rhodium 10 a platinum thermocouple
is a precious metal thermocouple, the anode is platinum-rhodium alloy, the anode is platinum, the short-term working temperature is 1600℃, and the long-term working temperature is 1300℃. It has good physical and chemical stability and is generally used for high temperature measurement with high accuracy requirements. But the material is more expensive, the thermoelectric potential is small, and the index number is S.
2, nickel-chromium-nickel-silicon thermocouple
It is the most stable of non-precious metals, and it is widely used. The positive electrode is nickel-chromium. The short-term working temperature is 1200℃, and the long-term working temperature is 900℃. The thermoelectric potential of this kind of thermocouple is 4 to 5 times larger than the previous one, and the linearity is better, and the error is generally (6-8) ℃. However, the thermoelectrode is not easy to be made uniform, easy to be oxidized, and the stability is poor. The index number is K.
3, Ni-Cr-Constantan thermocouple
Zhengquan is nickel chromium, short-term working temperature is 800℃, long-term working temperature is 60℃. It is a kind of thermocouple with the largest thermoelectric potential, and its measurement accuracy is high, but it is easily oxidized. The index number is E.
4, copper-constantan thermocouple
This is a thermocouple that is commonly used at low temperatures. The measuring temperature range is (-200-+200) ℃, with good stability, high sensitivity at low temperatures and low price. The index number is T.