Thermocouple temperature measuring instrument is commonly used in temperature measuring element, is made up of two different components of two ends synthesis loop conductor, juncture, when both ends of the thermocouple temperature is not at the same time, will produce thermal current in the circuit. If the work end of the thermocouple with the reference entity temperature difference, display instrument will indicate the thermocouple thermoelectric potential of the corresponding temperature value. Electric hot thermocouple will grows with the temperature measuring end, it is only with the size of the thermocouple temperature at the ends of the materials and relevant, has nothing to do with the hot electrode length and diameter. The appearance of all kinds of thermocouple is often due to the need to vary, but they are roughly the same basic structure, usually by the hot electrode, insulation sleeve to protect the main parts such as pipe and connection box, usually with digital display table, recording instrument and electronic regulator systems use commonly used thermocouple can be divided into two categories, thermocouple and non standard thermocouples. Using standard thermocouple refers to the national standard specifies its thermoelectric potential and the relationship between temperature, permissible error, and a unified standard score table of thermocouple, it has with matching display instrument to choose from. Non-standard thermocouple or on the order of magnitude less than the range using standardized thermocouple, generally no unified indexing table, mainly used for the measurement of some special occasions. Standardized thermocouple since January 1, 1988 in our country, the thermocouple and thermocouple were manufactured according to iec international standard, and specify the s, b, e, k, r, j, t seven standardization thermocouple type thermocouple for our country unified design. Types of thermocouple assembly thermocouple, thermocouple, thermocouple, pressure spring fixed thermocouples, high temperature thermocouple, platinum, rhodium thermocouple, anticorrosive thermocouple, wear-resistant thermocouple, thermocouple, high-pressure special thermocouple, handheld thermocouple, miniature thermocouple, the precious metal thermocouple, thermocouple, fast tungsten-rhenium thermocouples, single core thermocouples, and so on.