Common thermocouples can be divided into standard thermocouples and non - standard thermocouples.The call standard thermocouple refers to the national standard stipulated its thermoelectric potential and the temperature of the relationship, allow errors, and a unified standard dividing meter thermocouple, it has its supporting display instrument for selection.Non-standard thermocouple in the use range or order of magnitude are not as good as the standard thermocouple, generally there is no unified dividing meter, mainly used for some special occasions of measurement.
 


S, B, E, K, R, J, T seven types of standardized thermocouples are China's unified design thermocouple.
There are mainly S, R, B, N, K, E, J, T and so on.Where S, R, B belong to the noble metal thermocouple, N, K, E, J, T belong to the low metal thermocouple.
The following is an explanation 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 and nickel
Ni-cr-si ni-si
E/ni/cr/cu/ni
Platinum rhodium 10-platinum thermocouple
Platinum-rhodium 10-platinum thermocouple (S type thermocouple) is a precious metal thermocouple.The diameter of the coupling wire is 0.5mm and the allowable deviation is -0.015mm. The nominal chemical composition of the positive electrode (SP) is platinum-rhodium alloy, in which rhodium is 10%, platinum-90% and negative electrode (SN) is pure platinum, so it is commonly known as a single platinum-rhodium thermocouple.The maximum long-term operating temperature of the thermocouple is 1300℃, and the maximum short-term operating temperature is 1600℃.