Mineralisolierte Hochtemperatur Thermoelemente bis 2500°C
Mineralisolierte Mantelthermoelemente für den Hochtemperaturbereich werden in der Industrie und Forschung zur Messung sehr hoher Temperaturen z.T. unter besonders schwierigen Bedingungen eingesetzt. Die Auswahl des jeweiligen Thermoelements wird dabei durch die Umgebungseinflüsse, Temperaturanforderungen und der mechanischen Beanspruchung maßgeblich beeinflusst.
Das Thermopaar (Innenadern), sowie das Mantelmaterial bestehen bei mineralisolierte Hochtemperatur-Thermoelemente aus qualitativ hochwertigen Edelmetallen. Diese sind, bis auf wenige Ausführungen, grundsätzlich biegsam und können je nach Beschaffenheit Temperaturen von bis zu 2500°C messen. Dabei bieten Sie die gewohnten Vorteile einer hohen Messgenauigkeit, kurzen Ansprechzeiten, sowie eine langen Lebensdauer. Ein unentbehrliches Produkt mit einer großen Anwendungsvielfalt in Industrie und Forschung.
The choice of sheath material for sheathed thermocouples is of central importance as it protects the measuring point and the thermocouple from external influences. Extreme temperatures and a high level of interaction between the sheath material, temperature, atmosphere and area of application prevail in the high temperature range.
Particularly for type A and type C high-temperature thermocouples in inert, reducing or oxidizing atmospheres, specific sheath materials are required for the respective application. The correct design increases the resistance and therefore also the service life of the thermocouple.
When selecting the right sheath material for thermocouples for the high temperature range, it should be noted that some sheath materials are flexible and bendable in their design, while others can only be used in a rigid design. We would be happy to help you develop a solution for your application.
| Jacket material | Application temperature range | Minimum bending radius | Areas of application |
| Inconel600 (I) | 0 to 750°C | 5x diameter | Inert and oxidizing atmosphere, vacuum |
| 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 version | Reducing atmosphere, vacuum, inert atmosphere |
| Rhenium (RE) | 0 to + 2200°C | Rigid version | Inert and oxidizing atmosphere |
| Tungsten (W)* | 0 to + 2300°C | Vacuum, very low outgassing | |
| Molybdenum, 50% rhenium * | 0 to + 2300°C | Inert, hydrogen-containing, nitrogen-containing and ammonia-containing atmosphere, vacuum | |
| *Only on request |
| Sheath material | Outer diameter in mm | |||||||
| 1,0 | 1,5 | 1,6 | 2,0 | 3,2 | ||||
| Platinum (PR) | x | x | x | x | x | |||
| Tantalum (TA) | x | x | x | |||||
| Molybdenum (MO) | x | x | ||||||
| Rhenium (RE) | x | x | ||||||
| Molybdenum 50% Rhenium (MR) | On request | |||||||
AUSWAHL ISOLATIONSMATERIAL
High-temperature thermocouples also differ from conventional thermocouples in the choice of insulator, i.e. the insulation material. Usually, magnesium oxide is used as insulation between the thermocouple and the sheath of the thermocouple for thermocouples up to 1300°C. However, both magnesium oxide and aluminum oxide show a decreasing insulation resistance with increasing temperatures. However, magnesium oxide as well as aluminum oxide show a decreasing insulation resistance and a reduced ductility at increasing temperatures. For high temperature thermocouples type A and type C, hafnium oxide and beryllium oxide are often used as insulation material up to temperatures of 2500°C.
Hafnium oxide as insulation material in high-temperature thermocouples tends to be rather coarse-grained. Its ductility is lower than that of beryllium oxide, which is why the material is often used for high-temperature thermocouples in rigid designs. Beryllium oxide as an insulator in high-temperature thermocouples, on the other hand, is very suitable for flexible designs.
| Type | Material designation | Application temperature range | Properties |
| MgO | Magnesium oxide | 0 to 1600°C | Very hygroscopic, common insulation material in sheathed thermocouples. Only limited resistance behavior at high temperatures |
| AL2O3 | Aluminum oxide | 0 to 1550°C | Very good application behavior with the use of platinum |
| HFO2 | Hafnium oxide | 0 to 2200°C | Good properties at high temperatures, very good alternative to beryllium oxide, non-toxic, but with poor bending properties |
| BeO* | Beryllium oxide | 0 to 2200°C | Very good conductivity in the high-temperature range, very good resistance behavior |
| *Caution is advised when using berrylium oxide. Beryllium oxide is considered a toxic material. Incorrect or improper handling can lead to health problems |
High-temperature thermocouples also differ from conventional thermocouples in the choice of insulator, i.e. the insulation material. Usually, magnesium oxide is used as insulation between the thermocouple and the sheath of the thermocouple for thermocouples up to 1300°C. However, both magnesium oxide and aluminum oxide show a decreasing insulation resistance with increasing temperatures. However, magnesium oxide as well as aluminum oxide show a decreasing insulation resistance and a reduced ductility at increasing temperatures. For high temperature thermocouples type A and type C, hafnium oxide and beryllium oxide are often used as insulation material up to temperatures of 2500°C.
Hafnium oxide as insulation material in high-temperature thermocouples tends to be rather coarse-grained. Its ductility is lower than that of beryllium oxide, which is why the material is often used for high-temperature thermocouples in rigid designs. Beryllium oxide as an insulator in high-temperature thermocouples, on the other hand, is very suitable for flexible designs.
| Type | Material designation | Application temperature range | Properties |
| MgO | Magnesium oxide | 0 to 1600°C | Very hygroscopic, common insulation material in sheathed thermocouples. Only limited resistance behavior at high temperatures |
| AL2O3 | Aluminum oxide | 0 to 1550°C | Very good application behavior with the use of platinum |
| HFO2 | Hafnium oxide | 0 to 2200°C | Good properties at high temperatures, very good alternative to beryllium oxide, non-toxic, but with poor bending properties |
| BeO* | Beryllium oxide | 0 to 2200°C | Very good conductivity in the high-temperature range, very good resistance behavior |
| *Caution is advised when using berrylium oxide. Beryllium oxide is considered a toxic material. Incorrect or improper handling can lead to health problems |