J-type Thermocouple Temperature Measurement Range
Iron-copper-nickel thermocouple (J-type thermocouple), also known as iron-constantan thermocouple, is also a cheap metal thermocouple. The nominal chemical composition of its positive electrode (JP) is pure iron, and the negative electrode (JN) is a copper-nickel alloy, which is often vaguely called constantan. Its nominal chemical composition is: 55% copper, 45% nickel, and a small amount But very important elements such as manganese, cobalt, iron, etc., although it is called constantan, it is different from the constantan of nickel-chromium-constantan and copper-constantan, so EN and TN cannot be used to replace it. The coverage measurement temperature range of the iron-constantan thermocouple is -200~1200℃, but the temperature range usually used is 0~750℃
J-type thermocouple has the advantages of good linearity, large thermoelectromotive force, high sensitivity, good stability and uniformity, and low price. It is widely used by users.
J-type thermocouples can be used in vacuum, oxidation, reduction and inert atmospheres, but the positive electrode iron oxidizes faster at high temperatures, so the use temperature is limited, and it cannot be used directly and unprotected in a vulcanizing atmosphere at high temperatures.
1. The temperature range of platinum rhodium-platinum thermocouple is 630.74~1064.43℃
2. The temperature range of nickel-chromium-nickel-silicon thermocouple is 0~900℃
3. The temperature range of tungsten-rhenium thermocouple is 300~2000℃
4. The temperature range of Ni-Cr-Constantan thermocouple is 0~600℃
5. Copper-Constantan thermocouple temperature measurement range -200~100℃
S-type thermocouple has the highest accuracy, best stability, wide temperature measurement range, and long service life among the thermocouple series. It has good physical and chemical properties, thermoelectric potential stability and good oxidation resistance at high temperatures, and is suitable for oxidizing and inert atmospheres. Because of the excellent comprehensive performance of the S-type thermocouple, the S-type thermocouple, which conforms to the international temperature scale, has been used as an interpolating instrument for the international temperature scale for a long time. Although the rules of "ITS-90" will not be used as an internal inspection instrument for the international temperature scale in the future, However, the International Temperature Advisory Committee (CCT) believes that S-type thermocouples can still be used to approximately complete the international temperature scale.
