Smallest- and laboratory thermocouples

Micro- and laboratory thermocouple assemblies (18-TKL) are preferentially used for technical temperature measurements in liquid and gaseous media within a temperature range between 200°C and 1800°C.


Micro- and laboratory thermocouple assemblies differ from conventional thermocouple assemblies in their very small dimensions, light weight and variable mounting options. They also warrant exact temperature measurements within a constrained installation space. In consequence of design, these sensors also have very short reaction times.

There is a notable danger of “poisoning” noble metal thermocouples in micro- and laboratory thermocouple assemblies by substances diffusing through the protective fitting, such as those to be found in flue gas, for example. In order to avoid these types of influences, we recommend using a version employing gas-tight ceramic.

The thermal materials used by GÜNTHER GmbH for micro- and laboratory thermocouple assemblies are pursuant to DIN EN 60584.

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

Operation Temperature for Platinum-Rhodium /
Platinum Thermocouples

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 Micro- and Laboratory Thermocouple Assemblies: