Mineral insulated sheath thermocouples for the high temperature range are implemented in industry and research to measure very high temperatures and sometimes under especially difficult conditions. The selection of the respective thermocouple is significantly influenced by environmental factors, temperature requirements and the mechanical load.
The thermo pair (internal conductor), as well as the sheath material in the mineral insulated high temperature thermocouples is made from high quality precious metals. These are, apart from a few models, flexible and can according to the temperature, be measure at up to 2500°C. This provides you with the usual advantages of a high degree of measuring accuracy, short response times, and a long lifespan. An indispensible product with a large range of applications in industry and research.
Our strength is mineral insulated high temperature thermocouples which are individually produced according to your needs. From un-insulated thermocouples up to mineral insulated sheath thermocouples with compensating cable and/or connector solutions. We have a practical solution for every need! Talk to us when you are looking for the perfect solution
There are a variety of different types in the area of high temperature thermo elements according to DIN EN 60584. For the selection of a type, among other things, the temperature area and the limit deviation are of vital importance.
|Color code||Typ||Inner core / Thermo couple + / -||Application temperature|
|Type S||Platinum-Rhodium10% / Platin||0 to 1600°C|
|Type R||Platinum-Rhodium13% / Platin||0 to 1600°C|
|Type B||Platinum-Rhodium30% / Platin-Rhodium 6%||800 to 1700°C|
|Type C||Tungsten-5%Rhenium / Tungsten-26%Rhenium||0 to 2315°C|
|Type A||Tungsten-5%Rhenium / Tungsten-20%Rhenium||0 to 2500°C|
The selection of sheath materials for sheath thermocouples is of upmost importance because it protects the measuring point and the thermocouple from external influences. In the high temperature area, extreme temperatures rule and there is a high degree of interaction between the sheath material, temperature, atmosphere, and the area of implementation.
Especially at high temperatures, thermocouples type A and Type C, in inert, reducing or oxidizing atmospheres, specific sheath material are needed for the respective application. The correct design increases reliability and thereby also the lifespan of the thermocouple.
In the selection of the correct sheath material for thermocouples in the high temperature area it should be observed that a couple of sheath materials are flexible and bendable by design, while other can only be implemented in their rigid design. We will gladly help you develop a solution for your individual application. Contact us (link to contact form)
|Sheath material||Range of operation temp.||Min. bending radius||Application arera|
|Inconel600 (I)||0 to 750°C||5x Diameter||Inert and oxidizing atmosphere, Vakuum|
|Platinum (PR)||0 to + 1550°C||5x Diameter||Inert and oxidizing atmosphere|
|Tantalum (TA)||0 to + 2200°C||12x Diameter||Inert atmosphere, vacuum|
|Molybdenum (MO)||0 to + 2000°C||Rigid model||Reducing atmosphere, vacuum, Inert atmosphere|
|Rhenium (RE)||0 to + 2200°C||Rigid model||Inert and oxidizing atmosphere|
|Tungsten (W)*||0 to + 2300°C||Vacuum, very low gas emissions|
|Molybdenum, 50% Rhenium *||0 to + 2300°C||Inert-, hydrogene-, nitrogene- and ammonia containing atmosphere, Vacuum|
|*Up on request|
|Sheath material||Outer diameter in mm|
|Molybdenum 50% Rhenium (MR)||Up on request|
High temperature thermocouples differentiate themselves from the conventional thermocouples through the selection of insulators, i.e. of the insulation material. Normally with thermocouples of up to 1300°C, magnesium oxide is used as an insulator between the thermocouple and the sheath of the thermocouple. Magnesium oxide as well as aluminum oxide shows however, at rising temperatures, a sinking insulation resistance and a lowering of ductility. With high temperature thermocouples type A and type C, hafnium oxide and beryllium oxide are used as an insulation material up to temperature of 2500°C.
Hafnium oxide as an insulation material in high temperature thermocouples is prone to being coarse grained. Its ductility in contrast to beryllium oxide is lower, which is why the material is used for high temperature thermocouples in fixed designs. Beryllium oxide as an insulator with high temperature thermocouples is very suitable for flexible implementations.
|Type||Designation Material||Range application temp.||Attributes|
|MgO||Magnesium oxide||0 to 1600°C||Very hygroscopic, established insulation material in sheath thermocouples. Limited resistance at high temperatures|
|AL2O3||aluminum oxide||0 to 1550°C||Very good functional behavior under use of platinum|
|HFO2||Hafnium oxide||0 to 2200°C||Good attributes at high temperatures, good alternative to Beryllium oxide, non toxic, yet poor bending capabilities|
|BeO*||Berryllium oxide||0 to 2200°C||very good conductivity in high temp area, very good resistance behavior|
|*Caution should be exercised when using Beryllium oxide. It's understood as a toxic material. A wrong handling can lead to health problems.|
Un-insulated fine wires consist of a plus side and a minus side of a thermocouple. In the thermocouples they are available in type S, type B, type, R, type, C, and type A. The wire thickness of the thermocouple is available in the following thicknesses:0,25mm, 0,35mm, 0,51mm and 0,81mm The respective sides are separately developed on the roll and are available to be placed at individual lengths. The fine wire corresponds to the thermocouple DIN EN 60584.
|Type||Thermo couple + / -||Diameter wire in mm|
|Type S||Platinum-Rhodium10% / Platin||x||x||x||x|
|Type R||Platinum-Rhodium13% / Platinum||x||x||x||x|
|Type B||Platinum-Rhodium30% / Platinum-Rhodium 6%||x||x||x||x|
|Type C||Tungsten-5%Rhenium / Tungsten-26%Rhenium||x||x||x||x|
|Type A||Tungsten-5%Rhenium / Tungsten-20%Rhenium||x||x||x||x|
Design high temperature thermocouple with free insulated ends
Design high temperature thermocouple with compensating cable
Design high temperature thermocouple with compensating cable and connectors
Design high temperature thermocouple with connectors