The superiority of thermocouple performance in where? Release date: 2019 02 - Number 13 reading: zero

Thermocouple can bend, high pressure resistance, heat fast response time and strong and durable many advantages, such as it and industrial prefabricated thermocouple, as measure temperature transmitter, and usually display meter, recording meter and electronic regulator, at the same time can also be for prefabricated thermocouple. It can be directly measured in the production of chian from 0 ~ 800 ℃ in the scope of liquid, steam and gas medium, as well as the temperature of the solid surface. By welding on both ends of the two different ingredients of conductor, form a loop, directly measuring WenDuan call work side, the terminal end is called the cold end, also known as the reference. When work end and reference end there is temperature difference, will produce thermal current in the circuit, connected to display instrument, the instrument will indicate the thermocouple thermoelectric emf generated by the corresponding temperature value. The thermocouple thermoelectric emfs growth over the course 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. The structure principle of thermocouple is, is made up of a conductor, high insulation magnesium oxide, coat 1 cr18ni9ti stainless steel protecting tube, after many integrated control. Thermocouple products are mainly composed of terminal block, terminal and armoured thermocouple basic structure, and with various mounting device. The thermocouple thermoelectric power relation with temperature thermocouple thermometer belongs to the contact temperature measuring instrument. According to the principle of thermoelectric effect namely the seebeck effect is to measure the temperature, temperature measuring instrument is commonly used in temperature measuring element. Conductor A and B different materials into closed loops, one end of the contact temperature measurement points is called measure ( Or work side) , on the other side is called the reference end ( Or free end) 。 If measure end and reference end at temperature t and t0 is different, between A and B of the circuit is to produce A thermoelectric potential EAB ( t, t0) , a phenomenon known as the seebeck effect, thermoelectric effect. The EAB size with conductor on both ends of A and B materials and temperature t and t0 and change, this circuit is called prototype thermocouple. In practical applications, will be welded together at the end of the A and B as on the measured temperature t of the measuring junction of the thermocouple, and separate reference end, with wire connected to the display instrument, and keep the reference junction temperature t0 stability. Display instrument measured potential only t change with the temperature being measured. The characteristics of the thermocouple thermometer: ( 1) Wide measuring range. The commonly used thermocouple from - 50 ~ + 1600 ℃ can be continuous measurement, some special thermocouple minimum measurable to - 269℃( Such as gold iron nickel chrome) , up to + 2800 ℃ ( Such as tungsten - Rhenium) 。 ( 2) High precision measurement. Because of thermocouple direct contact with the object being measured, not affected by intermediate medium. ( 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. Thermocouple is a temperature sensing element, it can convert temperature signal into thermoelectric potential signal, through coordination, with electrical measuring instrument can measure the temperature being measured. Access in the thermocouple loop when the third metal material, the two contacts at the same temperature as long as the material, produced by the thermocouple thermoelectric is set to remain the same, which is not affected by the third metal access in the loop. Therefore, when the thermocouple temperature measurement, can be connected to the measuring instrument table, measured after the thermoelectric potential, can know the temperature of the measured medium. According to the thermoelectric potential function relation with temperature. Thermocouple indexing table can also be made. Indexing table is at the free end To = 0 ℃ temperature conditions. Different thermocouples with different indexing table. In theory, any two conductors can be made into thermocouple, but in fact is not all materials can make thermocouple, so the electrode materials of heat must satisfy the following points: ( 1) Requirements for the temperature coefficient of resistance material is small, high resistivity, good conductivity, heat capacity is small; Better repeatability, easy to mass production and exchange, to formulate unified indexing table; ( 2) Thermocouple materials subjected to temperature after can produce high thermoelectric potential and thermoelectric potential and temperature of the relationship between the best linear or approximate linear single valued function relation; ( 3) Good mechanical performance, material evenly; ( 4) Can measure the high temperature and in a wider temperature fan domestic application, after long-term use of physical, chemical properties and pyroelectric properties remained stable; In order to guarantee the thermocouple is reliable and steady work of thermocouple have the following requirements: ( 1) Compensation conductor should be connected to the free cod of a thermocouple to be convenient and reliable; ( 2) Two hot electrode welding of thermocouples must be strong; ( 3) Protect casing thermal electrode should ensure sufficient isolation and harmful medium. ( 4) Two hot electrode should be well insulated between each other, in case of short circuit;