Thermocouple is the temperature of the temperature measuring device is commonly used in industry, has the following characteristics: (1) high accuracy of measurement: thermocouple direct contact with the object being measured, is not affected by the medium in the middle of the. (2) thermal response time fast: thermocouple is responsive to temperature changes. (3) large measuring range: thermocouple from - 40 ~ + 1600 ℃ can be continuous temperature measurement. (4) reliable performance, good mechanical strength, long service life and easy installation.