tungsten-rhenium thermocouple

The characteristics of tungsten rhenium thermocouple are:

Thermoelectric wire has a high melting point (3300 ℃), low vapor pressure, and is highly prone to oxidation; Good chemical stability in non oxidizing atmosphere. High electromotive force, high sensitivity, mainly due to its affordable price.

At present, non-contact methods are commonly used to measure temperatures above 1600 ℃. However, this method has a large error, and using the contact method can accurately measure the true temperature. In high-temperature thermocouples, precious metal thermocouples are expensive and can only reach temperatures below 1800 ℃. However, tungsten rhenium thermocouples not only have a high temperature measurement limit, but also have good stability. Therefore, tungsten rhenium thermocouples are widely used in industries such as metallurgy, building materials, aerospace, aviation, and nuclear energy. China has abundant tungsten resources, and tungsten rhenium thermocouples are cheap and can partially replace precious metal thermocouples (platinum rhodium thermocouples). They are a promising temperature measurement material in the field of high temperature testing. Its high operating temperature can reach 2800 ℃, but data dispersion occurs above 2300 ℃. Therefore, it is recommended to use a temperature of around 2000 ℃.

Tungsten rhenium thermoelectric dipoles are prone to oxidation and are suitable for use in inert or dry hydrogen gas, or with dense protective tubes to isolate them from oxygen before use. Cannot be used in a carbon containing atmosphere (such as in an atmosphere containing hydrocarbons, where corrosion occurs at temperatures exceeding 1000 ℃). Tungsten or tungsten rhenium is prone to generate stable carbides in a carbon containing atmosphere, which can reduce its sensitivity and cause brittle fracture. In the presence of hydrogen gas, it can accelerate carbonization.

The issue of oxidation resistance of tungsten rhenium thermocouples has always been a topic of concern for scholars at home and abroad, and efforts have been made to study and solve it. Prefabricated high-temperature and high-pressure tungsten rhenium thermocouple, with a temperature measurement range of 0-1800 ℃, is widely used in metallurgy, coking, chemical kilns, heat treatment, glass and other industries. It has the advantages of high accuracy, low price, stable performance, and is not limited by the working environment and atmosphere. It is an ideal product to replace platinum rhodium thermocouples. The tungsten rhenium thermocouple produced by our company has been widely used in many units, and its technical specifications are as follows:

1 z. UI high temperature measurement temperature: 1800 ℃

2. Temperature measurement accuracy: ≤ 0.5%

3. Insulation resistance: ≥ 30 MΩ

4. Measurement rate: ≥ 98%

5. Reaction time:< 5 s

At present, the tungsten rhenium thermocouples produced by our company are divided into three categories:

One type is the use of fine ceramic protective tubes The specifications of ceramic tubes include: diameter of Ø 8, Ф10，Ф12，Ф14，Ф16， Length of 300-1100mm, this type of thermocouple is not limited by the working environment and atmosphere, and can be used for a long time in any atmosphere. The temperature measurement range is 0-1800 ℃

The other type is pure molybdenum protective tube The specifications for molybdenum and tungsten tubes are: diameter of 6, Ф8，Ф10mm， The length of this thermocouple is 500-700mm, and it can only work for a long time in a vacuum, reducing or inert gas protected environment. The molybdenum tube is best used for long-term use at temperatures below 1800 ℃, and the short-term use temperature can reach 2000 ℃;

Another type is tungsten protective tube As for tungsten tubes, they can work for a long time at 2100 ℃, but they are difficult to process, making them very expensive.