The thermocouple thermoelectric emfs growth over the course of measuring the temperature, the size of the thermoelectric potential and thermocouple temperature difference on both ends of the conductor material and, only has nothing to do with hot electrode length and diameter. 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. Thermocouple steel furnace hot blast stove in iron and steel industry is mainly used to provide hot air to the smelting process, the arch temperature measuring thermocouple long running in 1200 ~ 1250 ℃ high temperature, high temperature can reach 1280 ℃, and strong vibration in the process of air supply. Because each enterprise use different coal quality, production of gas cleanliness is different also, hot blast stove often exist in the process of burning sulfur, phosphorus compounds, such as required thermocouple protection tube can resistance to high temperature air flow scouring corrosion, wear particles and high temperature gas. Traditional thermocouple protection tube, such as jade, disilicide key and ordinary silicon carbide steel due to the porosity, the cause of the high temperature strength, high temperature brittleness can easily lead to protect casing brittle fracture, accidentally silk pollution, corrosion, short service life of thermocouple, no reliable operation cycle. Protect casing nickel-based superalloy in presence of phosphide gas when using high temperature corrosion failure time is about 20 a 30 hours. My company in the long-term practice of all kinds of hot blast stove dome temperature measurement, constantly sum up experience and achievements in the field of applied materials, using special SiC or heat resistant alloy as external protecting tube, using corundum as protection tube, and the measuring end processing, this kind of special thermocouple, successful development in hot blast stove dome on the user to use more than half a year. Scope of application and use temperature under the condition of the gas contain phosphide, outer casing by the introduction of German technology to produce a new type of silicon carbide to protect casing, the product porosity approximate zero. Has high air tightness, excellent oxidation resistance, corrosion resistance ability; High hardness, excellent wear resistance; High strength, strength increases with temperature rise. Isolated from a variety of harmful gas high temperature of the casing corrosion and erosion, the long-term use of around 1420 ℃ condition. Under the condition of the gas does not contain phosphide, the outer casing of heat-resisting alloy steel matrix, and the use reached the international advanced surface treatment technology, forming a 0 in the surface of metal casing. 5 ~ 1. 2 mm thick metal ceramic coating material. Coating material has high hardness, Up to HV1450) , high density ( ≥99. 5%, low porosity ( Hot blast stove thermocouple is designed for the iron and steel industry development, it has a high temperature resistant, fight corrode, air scour resistance and long service life, etc. Suitable for blast furnace, the hot blast stove dome hot mouth or temperature measurement, in areas such as the hot air pipe can also be used for natural gas, coal, cement kiln temperature measurement, etc. The structure principle of thermocouple 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 thermocouple basic structure, and with various mounting device. Thermocouple insulation type and hull type two kinds. Can bend, high pressure resistance, heat fast response time and strong and durable many advantages, such as it and industrial use, as measure temperature sensor, and usually display meter, recording meter and electronic regulator, at the same time, also can be used as a temperature sensing element. It can directly measure all kinds of production process from 0 ℃ ~ 800 ℃ in the scope of liquid, steam and gas medium, as well as the surface temperature of the solid. And compared to the thermocouple is flexible, high pressure resistance, thermal response time is short and strong and durable, etc. Thermocouple temperature measurement principle is based on thermoelectric effect. Connect the two different conductor or semiconductor into closed loops, when the two contacts in temperature is not at the same time, the circuit will produce thermoelectric potential, this kind of phenomenon called the thermoelectric effect, also known as the seebeck effect. Thermocouple as the temperature measurement sensor, usually with temperature transmitter, controller and display instrument, such as process control system, to directly measure or control in the production of a variety of 0 Fluid over a range of 1800 ℃, steam and gas medium and solid surface temperature. Thermocouple calibration method of metallic melts fast thermocouple calibration method and device. The device is mainly composed of a can accommodate two measured accidentally the flat heated quartz tube end of coil, two with her being measured thermocouple and the corresponding temperature control of the same shape according to the output device. Calibration verification method: first use two thermocouple find the two calibration in this flat heating coil accidentally thermoelectric potential of the same point, replacing one of the calibration with checked accidentally accidentally, in the case of other conditions unchanged, after being checked my reading stability compared with the calibration my reading can be accidentally quantities are accurate. Characteristics: a, the device is composed of a flat heating coil, a pair of calibration of thermocouple and display output of temperature control device. B and verification method is to first two calibration thermocouple from relative insert on both ends of the heating coil, the hot end of thermocouple, thermocouple location in the heating coil made by changing the calibration two calibration of the thermocouple thermoelectric power, the same measured fast thermocouple to replace one of the calibration of thermocouple, read the thermoelectric potential value of measurement under the steady state and compare the calibration thermocouple thermoelectric potential can be measured quickly the accuracy of the thermocouple. 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 sensor, through the compensating conductor and digital display meter, recording meter and electronic regulator.