High-performance Thermocouples and Feed-Throughs

The ultra-premium type “T” thermocouple wire is available in 3- and 7-strand versions, which are coated with a clear PTFE outer insulation.

The three-stranded wire is used where limited space is available or where the wire needs to be routed through tight openings such as plastic tubes or terminated in a small filter housing. It has an outer diameter of 1.88 mm and can be used in temperatures ranging from -196 ºC (liquid nitrogen) up to a temperature of +200 ºC. The seven-stranded wire has an outside diameter of 3.05 mm and is used where additional strength of the probe is required.

• 3-strand Litz wire: ideal where flexibility and diameter of the lead are a priority, such as when feeding wires through door seals.
• 7-strand Litz wire: typically used where particular emphasis needs to be placed on robustness and mechanical stability

Thermocouples with Kapton jacket for temperatures up to 350 °C are also available on request (can only be used in dry conditions).

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    What is a thermocouple?

  
  Thomas Johann Seebeck discovered that connecting two conductors of different materials and applying a different temperature at this connection point will result in a voltage drop at the other end of the conductors, which is related to the temperature change.  This Seebeck effect (also called the thermoelectric effect) allows construction of a temperature measuring sensor (= thermocouple) from 2 wires of different materials.
  
  8 materials are of particular importance, as they can be combined to achieve different temperature ranges and accuracy classes, as listed in standards such as IEC60584 and ASTM E230. These different thermocouple compositions are denoted by the letters J, K, E, T, R, S, B and N.
  
  When using thermocouples to measure temperature, cold junction compensation must also be considered. As already described above, the thermoelectric effect is based on two different materials (e.g. copper and constantan) generating a difference in potential at the tip of the thermocouple - the “hot junction”. Since a thermocouple wire, however, also needs to be connected to a measuring device whose electrical connections are usually made of copper, a second thermoelectric effect exists at this “cold junction”, where again two different materials make contact. Therefore, the overall generated voltage consists of the voltage generated at the measuring tip, offset with the voltage drop occurring at the meter side (cold junction compensation).