How to distinguish thermocouple models?

Recently, customers often ask questions about thermocouple models. The following editors summarize:

Commonly used thermocouples can be divided into two categories: standard thermocouples and non-standard thermocouples. The so-called standard thermocouple refers to a thermocouple. Its national standard specifies the relationship between its thermoelectric potential and temperature, and its allowable error, and has a unified standard scale. It has matching display tools for selection. In the scope of use or order of magnitude, non-standardized thermocouples are inferior to standardized thermocouples, and there is usually no unified index table, which is mainly used for measurement in some special occasions.

The index numbers of thermocouples are mainly S, R, B, N, K, E, J, T, etc. Among them, S, R and B belong to precious metal thermocouples, and N, K, E, J and T belong to low-cost metal thermocouples.

 The following is a description of the thermocouple index number:

  S platinum rhodium 10 pure platinum

  R platinum rhodium 13 pure platinum

  B platinum rhodium 30 platinum rhodium 6

  K nickel chromium nickel silicon

  T pure copper copper nickel

  J iron copper nickel

  N Ni-Cr-Si Ni-Si

  E nickel chromium copper nickel

(S-type thermocouple) platinum rhodium 10 platinum thermocouple

Platinum rhodium 10 platinum thermocouple (S type thermocouple) is a kind of precious metal thermocouple. The diameter of the coupling line is specified as 0.5mm, and the allowable deviation is -0.015mm. The nominal chemical composition of the positive electrode (SP) is platinum-rhodium alloy, which contains 10% rhodium and 90% platinum, and the negative electrode (SN) is pure platinum. Commonly known as single platinum rhodium thermocouple. The long-term maximum use temperature of the thermocouple is 1300°C, and the short-term maximum use temperature is 1600°C.