Main types of K type thermocouple (nickel chrome – nickel silicon thermocouple) : has good linearity, thermoelectric emfs is larger, high sensitivity, stability, and the advantages of good uniformity, temperature measuring range is in commonly – 200 ℃ ~ 1300 ℃, is one of the most widely used industrial thermocouple. S type thermocouple (10 – platinum platinum-rhodium thermocouples), high precision, good stability and temperature limit of up to 1600 ℃, but the price is relatively high, often used in high temperature and the precise temperature measurement occasions, such as glass, ceramics and other industries of high temperature furnace temperature measurement. E type thermocouple (copper nickel chrome – nickel thermocouple) : in the commonly used thermocouple, the thermoelectric emfs, largest highest sensitivity, in 200 ℃ ~ 900 ℃ temperature range has good stability, is suitable for measuring temperature in oxidation or inert atmosphere, especially in low temperature measurement applications. T thermocouple (copper, copper nickel thermocouple) : has good linearity and high sensitivity, especially in the region of the low temperature performance is superior, the temperature measurement range is in commonly – 200 ℃ ~ 350 ℃, often used in low temperature measurement and temperature control, such as refrigerator, air conditioner, temperature detection of the equipment.

Application scenarios: industrial production in iron and steel, chemical, electric power and other industries, used for measuring the melting pot, of temperature in the reaction kettle, boiler equipment, for the automation of production process control and quality monitoring provides key data. For example, in the ironmaking furnace of a steel plant, the thermocouple monitors the temperature in the furnace in real time to ensure that the temperature of molten iron meets the production requirements and ensures the quality of steel. Scientific research: in the

research fields such as physics, chemistry, materials science, to accurately measure the temperature variation in the process of experiment, to provide the accurate temperature data support for scientific research. For example, in the study of thermal properties of materials, the temperature of materials in the heating or cooling process is accurately measured by thermocouple, and the thermal expansion, heat conduction and other properties of materials are analyzed. In medical field: medical equipment, such as sterilization equipment and radiotherapy equipment, used for monitoring and controlling temperature, ensure the safety of the equipment operation and treatment effect. For example, in the medical high pressure steam sterilizer, the thermocouple monitors the temperature in the sterilization room in real time to ensure that the sterilization process reaches the specified temperature and time to achieve complete sterilization. For the automotive industry: measurement of auto engine coolant temperature, exhaust temperature, etc., help the engine control system for precise fuel injection and ignition timing control, improve engine performance and fuel economy, at the same time monitor the working state of the engine, to prevent overheating failure, etc.