How to control the stability of the thermocouple
The highest accuracy thermocouple in the development of measurement sensor, the product best economy,therefore it became at present we use in temperature measuring elements as a type of wide, the direct measurement of the temperature, and the temperature signal into electrical signal through the thermoelectric EMFs, meter (two meters) into the measured medium temperature. Thermocouple, appearance is often due to the very not identical, but their basic structure were roughly the same, usually composed of a hot electrode,insulating sleeve protective pipe and the junction box of the main part, usually and display instruments,recording instruments and supporting the use of electronic regulator. Thermocouple measurement between the hot end and a cold end temperature difference. In order to obtain the absolute temperature sensing hotend, must test the cold end temperature and the corresponding adjustment of the thermocouple output. Now,in the thermocouple cold end temperature signal processing unit input often rely on material with high thermal conductivity maintaining tablets. The thermal conductivity of 381W/mK copper is ideal material. The inputconnection must be electrically isolated, hot rolling road to on-chip. The signal processing unit is ideally should be in this isothermal environment.
Thermocouple stability, due to the use of different temperature, atmosphere, for the same sensor, such as the maximum use temperature of K type thermocouple because of different diameter and diameter change, the same K type thermocouple is also due to the different structure of the stability, also has the very big difference.In the choice of thermocouple, must according to the use conditions are considered: common temperature andthe highest use temperature; oxidation reduction using atmosphere; anti vibration performance. For assemblytype thermocouple, atmosphere effect, first of all depends on the material and the thermocouple protection tube structure, therefore, familiar with various protection tube, to master the physical material, chemical properties is very necessary.