"Calibration Number" in Thermocouples and Temperature Measuring Instruments
In thermocouples and temperature measuring instruments, the "division number"/division number of thermocouples mainly includes S, R, B, N, K, E, J, T, etc. Among them, S, R, and B belong to precious metal thermocouples, while N, K, E, J, and T belong to low-cost metal thermocouples.
The characteristic of S scale is strong antioxidant performance, suitable for continuous use in an oxidizing and inert atmosphere, with a long-term use temperature of 1400 ℃ and a short-term use temperature of 1600 ℃. Among all thermocouples, the S scale has a high degree level and is usually used as a standard thermocouple;
Compared with the S scale, the R scale has almost identical performance except for a 15% increase in thermoelectric potential;
The B division mark has a very small thermoelectric potential at room temperature, so compensation wires are generally not needed during measurement. Its long-term usage temperature is 1600 ℃, and its short-term usage temperature is 1800 ℃. It can be used in oxidizing or neutral atmospheres, as well as for short-term use under vacuum conditions.
The characteristics of the N scale are strong high-temperature oxidation resistance at 1300 ℃, good long-term stability of thermoelectric potential and reproducibility of short-term thermal cycles, and good resistance to nuclear irradiation and low temperature. It can partially replace the S scale thermocouple;
The characteristic of K scale is strong antioxidant performance, suitable for continuous use in an oxidizing and inert atmosphere, with a long-term use temperature of 1000 ℃ and a short-term use temperature of 1200 ℃. Widely used in all thermocouples;
The characteristic of the E-scale mark is that it has a high thermoelectric potential and sensitivity among commonly used thermocouples. Suitable for continuous use in an oxidizing and inert atmosphere, with a temperature range of 0-800 ℃;
The characteristic of the J division mark is that it can be used in both oxidizing atmospheres (with an upper temperature limit of 750 ℃) and reducing atmospheres (with an upper temperature limit of 950 ℃), and is resistant to H2 and CO gas corrosion. It is commonly used in refining and chemical industries;
The characteristic of the T-scale is that it has a high accuracy level among all low-cost metal thermocouples, and is usually used to measure temperatures below 300 ℃.
