What types of high-temperature resistant platinum rhodium thermocouples can be classified according to their composition?

The shortcomings of high-temperature resistant platinum rhodium thermocouples are thermoelectric potential, low thermoelectric potential, low sensitivity, decreased mechanical strength at high temperatures, high sensitivity to pollution, expensive precious metal materials, and therefore a large one-time investment. The S-type thermocouple, also known as the single platinum rhodium thermocouple, has an S division mark and is mainly used to measure the temperature of the medium between 0 and 1600 degree . It is a category of precious metal thermocouples. Normal use in high-temperature environments such as coking plants and steel mills.

High temperature resistant platinum rhodium thermocouples have the advantages of high accuracy, stability, wide temperature measurement range, and long service life in the thermocouple series. It has good physical and chemical properties, stable thermoelectric potential, and excellent oxidation resistance at high temperatures, making it suitable for both oxidizing and inert atmospheres. Due to its excellent comprehensive performance, the S-type high-temperature resistant thermocouple, which meets the requirements of using temperature scales, has long been used as an interpolation instrument for temperature scales. Although "ITS-90" stipulates that it will no longer be used as an internal inspection instrument for temperature scales in the future, the Temperature Advisory Committee (CCT) believes that S-type thermocouples can still be used to approximate temperature scales.

Material of protective tube for high-temperature resistant platinum rhodium thermocouple:

The materials commonly used as protective tubes for platinum rhodium thermocouples include aluminum tubes, corundum tubes, and high-temperature resistant alloy materials.

1. High aluminum tubes are used as protective tubes for S-type thermocouples and R-type thermocouples. They are typically used at temperatures Less than or equal to 1300 degree , but their density and temperature resistance are inferior to those of corundum tubes.

2. High aluminum tubes are used as protective tubes for B-type thermocouples, and can also be used as protective tubes for S-type thermocouples and R-type thermocouples. The long-term use temperature of corundum tube is 1600 degree , the short-term use temperature is 1800 degree , the load softening point is 1900 degree , and the maximum use temperature is 1950 degree . Users should choose 99 corundum tubes with high firing temperature and good density when selecting corundum tubes.


1. Platinum rhodium 30 platinum rhodium 6 thermocouple: with division number B, also known as dual platinum rhodium thermocouple; Long term measurement of 1600 degree temperature, short-term measurement of 1800 degree temperature; B-type thermocouples are classified into Class II and Class III according to usage requirements and thermoelectric characteristics.

2. Platinum rhodium 10 platinum thermocouple: division number S; It can measure a temperature of 1300 degree for a long time and 1600 degree for a short time. The protective tube is usually made of high aluminum tube or corundum tube; S-type thermocouples are classified into Class I and Class II according to usage requirements and thermoelectric characteristics.

3. Platinum rhodium 13 platinum thermocouple: division number R; It can measure a temperature of 1300 degree for a long time and 1600 degree for a short time. The protective tube is usually made of high aluminum tube or corundum tube; R-type thermocouples are classified into Class I and Class II according to usage requirements and thermoelectric characteristics.