Thermocouples with ceramic protection tube and sheath measurement insert

Straight line thermocouple assemblies with ceramic protection tube and mineral-insulated gauge slides (15-TKM) are used for common temperature measurement up to 1200°C, mainly in gaseous media.


For sensors of this product line, mainly base metal thermocouples are employed, combining the advantages of mineral-insulated gauge slides on one hand, and the advantages of technical ceramics on the other hand.

The individual properties of the most common ceramic types can be found on page 63, in the chapter “Technical Information”. Additionally and in contrast to thermocouples, mineral-insulated gauge slides are easily exchangeable, they are resilient to temperature changes, vibration and impact resistant. In consequence of the compact and slender configuration of the mineral-insulated gauge slides, enough space usually remains to allow for the insertion of an additional mineral insulated  thermocouple for measurement verification if necessary.

During measurement and control processes, often high operational wear occurs due to corrosion and abrasion, which even high grade metal protective tubes are not able to withstand. In these scenarios, thermal sensors with protective tubes made of heat-resistant, technical ceramics allow for increased holding time in many instances.

Thermoelectric voltages and tolerances of our mineral-insulated gauge slides are pursuant to DIN EN 60584, Class 1.

Characteristics of the most usual ceramic types

  Unit porous
Type pursuant DIN / C530 C610 C799
Thermal Shock Resistance / Very Good

to Good

Impermeability / Porous Gas-Tight Gas-Tight
Maximum Constant Temperature °C 1650 1600 1850
Al2O3-Content % 73-75% 60 99,7
Volume Weight g*m3 2,35 2,5 3,8-3,93
3-Point Bending Strength MPa 35 120 300
C-Modul GPa 60 110 370

Maximum application temperatures for Platinum-Rhodium-Platinum thermoelectric pairs

Type Diameter Maximum
S 0,35 mm 1350°C
S 0,50 mm 1600°C
R 0,35 mm 1350°C
R 0,50 mm 1600°C
B 0,35 mm 1600°C
B 0,50 mm 1800°C

Application Examples for Thermocouple Assemblies with Ceramic Protection Tube and Mineral-Insulated Gauge Slide