Thermocouple and ordinary type thermocouple is what _ instrument

The working principle of thermocouple are two different ingredients of conductor on both ends of the welding, forming circuit, direct measure WenDuan call side, the measurement end terminal called reference. When measuring end and reference end there is temperature difference will produce thermoelectric emf in the loop, to display instrument, the instrument will indicate the thermocouple thermoelectric emf generated by the corresponding temperature value. The thermocouple thermoelectric emf will increase with the rising of measuring the temperature, the size of the thermoelectric emfs and thermocouple temperature difference on both ends of the conductor material and, only has nothing to do with hot electrode length and diameter. Thermocouple is made up of hot electrode, magnesia insulation and 1 cr18ni9ti stainless steel protecting tube was drawn. Thermocouple is mainly composed of terminal block, terminal and thermocouple elements such as the basic structure, and with various mounting device. Basic principle of thermocouple temperature measurement will be two different welding material A conductor or semi-conductor A and B to form A closed loop, when the conductor A and B two persistent point temperature difference between 1 and 2, occurs between the electromotive force, and thus form the size of A current in the circuit, this kind of phenomenon called the thermoelectric effect. Thermocouple is in using this effect to work. If we are to use normal thermocouple is first of the two kinds of thermocouple has certain understanding. Ordinary electric coupling generally by the hot electrode, insulation tube, to protect casing and junction box parts, such as type and electric coupling is the electric heating wire, insulation material and metal protective casing combination after assembly, after stretching processing from a combination of a solid. But it takes a special electric coupling of electrical wires to pass, this kind of wire we called compensation conductor. Different electric I need different compensation conductor, its main function is connected to the electric coupling, electric heating my reference end away from the power, so that the reference temperature stability. Compensation wire is divided into compensation type and extended type two kinds, extend the chemical composition of the wire and the compensation of electro-thermal coupling is the same, but in practice, to extend the type of wire is not use of the same material and electric coupling metals, generally USES and electric coupling with the same wire instead of electron density. Compensation and electric coupling connection of the wire are generally not very clear, the positive connection of the electric coupling compensation conductor should be red line, while the cathode connecting the rest of the color. Most of the material compensating lead wires are commonly used copper nickel alloy. Thermocouple is one of the industry commonly used temperature detecting element. The working principle of the thermocouple is based on baker ( seeback) Effect, that is, two different components of conductor ends connected into a circuit, such as two different connection end temperature, then to produce the physical phenomenon of thermal current in the circuit. Its advantage is that (1) high accuracy of measurement. Because of thermocouple direct contact with the object being measured, not affected by intermediate medium. (2) the measurement range. The commonly used thermocouple from - 50 ~ + 1600 ℃ can renew edge measurement, some special thermocouple low measurable to - 269℃（ Such as gold iron nickel chrome) Up to + 2800 ℃ ( Such as tungsten - Rhenium) 。 3. Simple structure, easy to use. Thermocouple is usually composed of two different kinds of metal wire, but is not limited by the size and the beginning of, outside has protective casing, which are very convenient.