Thermocouple Type C: Type C (Tungsten 5% Rhenium – Tungsten 26% Rhenium) thermocouples are suited for measurements in the 0 – 2320°C (32 – 4200°F) range.
Because type C can reach temperatures as high as 2320°C (4200°F), they are widely used in space vehicles, nuclear reactors, industrial heating, or wherever extremely high temperatures may be present. They are also in widespread use for high-pressure research. This thermocouple is well suited for vacuum furnaces at extremely high temperatures.
Type C can be used in certain applications, but is not suitable for most industrial process services. In addition to being costly, type C is not practical for withstanding the rigours of many typical high temperature process environments. There are several reasons, one of which is that tungsten burns when exposed to oxygen. Therefore, it must be operated in a vacuum or under an inert gas, and must never be used in the presence of oxygen at temperatures above 260°C (500°F). An example of this type of failure occurring is when a glass light bulb breaks.
Additionally, tungsten becomes embrittled as it is heated and cooled over a range of temperatures. Normal vibration in an incinerator or Claus unit will cause failure due to breakage of the embrittled wire, even in an inert gas atmosphere.
For assistance in choosing the proper sensor for your process, please contact us and our Temperature and Process Engineers will be happy to assist you!
Continue reading… Part 4