Tungsten rhenium 3-tungsten rhenium 25 thermocouple is a high temperature resistant thermocouple. It has the advantages of good temperature-potential linear relationship, reliable thermal stability, and low price. With the display instrument, it can directly measure the temperature of liquid, steam and gas medium. It can partially replace platinum-rhodium thermocouples as high-tech metallurgical industry, high-temperature electronic thermoelectric system structural engineering and space transportation tools, and ultra-high temperature measurement tools for nuclear reactors. The relationship between the thermoelectric potential and temperature of the tungsten-rhenium thermocouple conforms to the ZBN05003-88 index table, which is equivalent to ASTME696-84 standard. It can be used in the range of 0 ~ 2300 ℃ under vacuum, reduction and inert atmosphere. Tungsten rhenium couplers with special protection tubes can also be used for a long time in an oxidizing atmosphere at 1600 ° C, and their price is lower than that of platinum-rhodium thermocouples.
分度号有WRe3-WRe25，WRe5-WRe20，WRe5-WRe26，W-WRe26温度一热电势分度表(见ZBN05003—88钨铼热电偶丝及分度表) Tungsten-rhenium thermocouple indexing numbers are WRe3-WRe25, WRe5-WRe20, WRe5-WRe26, W-WRe26 temperature-thermoelectric indexing table (see ZBN05003—88 tungsten-rhenium thermocouple wire and indexing table)
In a certain temperature range, a pair of insulated wires with the same nominal value of the matching thermoelectromotive force is called a compensation wire. Use them to connect a thermocouple to a measurement device to compensate for errors caused by temperature changes at the junction of the thermocouple.
Compensation wire characteristics:
① Stable thermoelectric characteristics, good electrical insulation performance and long service life.
② Flexible, good bending performance, easy to use.
③ The coating material is stable and reliable, and has certain temperature resistance and cold resistance.
Compensation wire structure and use:
① Compensation wire is composed of core wire and insulation coating;
② Compensation wires should be divided into two types: extension type and compensation type due to different core alloy materials. Extension type compensation wires include NX (nickel chromium silicon-nickel silicon magnesium), KX (nickel chromium 10-nickel silicon 3), EX (nickel Chromium 10-copper-nickel 45), JX (iron-copper-nickel 45), TX (copper-copper-nickel 45), compensating compensating wires are SC and RC (copper-copper-nickel 0.6), KC (copper-copper-nickel 40) , NC (iron-copper-nickel), etc .;
③ The insulation covering and outer covering materials of the compensating wire are polyvinyl chloride, polytetrafluoroethylene, glass fiber, quartz yarn and ceramic fiber, etc .; the metal shielding layer is stainless steel mesh, etc.
④ The thermocouple compensation wire is connected with the display instrument, recorder or computer to form a temperature measurement system, which is widely used in power, metallurgy, petroleum, chemical, textile and other industries, as well as national defense and scientific research departments.
的主要技术参数： Second, the main technical parameters of tungsten-rhenium thermocouple :
Operating temperature (℃) Tolerance
1300 ~ 1700 0.5% t
0 ~ 2300 1% t
在周围空气温度为20士15℃，相对湿度不大于85％，热电极与外保护管之间绝缘电阻应大于100MΩ.m。 3. Insulation resistance at room temperature: The temperature of tungsten-rhenium thermocouple in the surrounding air is 20 ± 15 ℃, and the relative humidity is not more than 85%. The insulation resistance between the hot electrode and the outer protective tube should be greater than 100MΩ.m.
4. Thermal response time: Thermal response time 0.5≤180S
Five, WRe 3 / WRe25 thermocouple outer protection tube
(l) Silicon carbide tube (Sic) can be used in an oxidizing atmosphere below 1600 ° C
(2) Molybdenum silicide tube (Mosi2) is used in the air below 1600 ℃ and some corrosive atmosphere (supplied by agreement)
(3) Molybdenum tube (Mo) is used in vacuum below 2300 C.
(4) Tantalum tube (Ta) is used in vacuum below 2300C (supplied by agreement)