Sheath thermocouples without protection tube

Sheathed thermocouple assemblies without protection tube (20-TOM) are used in almost every branch of industry up to a temperature of 1100°C, with a platinum-rhodium-mantle up to 1300°C.


Sheathed thermocouple assemblies essentially consist of thermo wires (inner conductors) insulated with high-purity, condensed magnesium oxide powder and an external mantle (sheath) of heat-resistant high-grade steel or nickel alloy (e.g. Inconel 600®).

Sheathed thermocouple assemblies are available in single, double or triple element version. The outer diameter lies somewhere between 0,25 mm and 8,0 mm depending on technical assembly and customer preference. As a result of their structure, sheathed thermocouple assemblies offer numerous advantages when compared to their conventional counterparts.

  • Small dimensions for temperature measurements at measuring sites with difficult accessibility (any desired length available)
  • Short response time for exact measurements of temperature fluctuations
    Vibration and pressure resistant
  • Optimal protection of inner conductors against corrosion, oxidation, mechanical damage and chemical contaminationIncreased stability of electric insulation compared to ceramic insulated thermocouples
  • Simple and sealed assembly


We are able to deliver every current design and diameter of sheathed thermocouple assemblies with mounted sockets, connection heads, compensation cables, as well as accessories and mounting structures of every type.

For specialised requirements and standards (such as AMS, CQI-9, etc.), we offer sheathed thermocouple assemblies available with exceptionally narrow tolerances, often referred to as “better class 1”.

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

Application Examples for Sheathed Thermocouple Assemblies without Protection Tube: