Resistance Thermometers Designed for Hazardous Areas (ATEX Applications)

INSTROTECH offers Kobold’s TWL resistance thermometers, specifically designed to be used in hazardous areas. The DIN-compliant products are supplied with ATEX approvals for ignition protection Exd or Exia.

The Kobold TWL resistance thermometers comprise a rugged installation fitting made of stainless steel with thread, flange or weld-on connection, a connection head out of aluminium casting and a removable measuring element. The measuring insert can be replaced without emptying the installation, since the customised thermowell remains in the installation and seals the process. The instruments are supplied with the ignition protection Exd as a standard and therefore can be installed in relevant hazardous areas.


Head Transmitter

Resistance thermometers with head transmitter are used whenever a measuring signal must be transported long distance without any disturbance. The head transmitter which is encapsulated in epoxide resin is located right in the connection head and delivers a temperature-linear output signal of 4-20 mA. The head transmitter is available with standardised communication systems such as HART® protocol or PROFIBUS®/Fieldbus®.

Depending on customer requirement, the temperature sensor can be carried out as 2-, 3- or 4-wire circuit.  Alternatively, these sensors can be designed as single or double resistance thermometers. The exception here would be the 4-wire version, which can only be built with one Pt100 due to lack of space. As an option the resistance thermometers can be supplied with a head transmitter.

Beside the available resistance thermometers according to DIN standard, there are customised versions relating to the immersion length, the connection head, the materials, the process connection or the tolerance classes deliverable on request.

Kobold TWL features:

  • Measuring ranges: -80°C…+600°C
  • Pt100 sensor class A, respectively class B
  • Output: Resistance or analogue 4-20 mA
  • Thermowells up to 1000, 3000 respectively 5000 mm (depending on model)
  • Option: Head transmitter with HART®-protocol or PROFIBUS®/Fieldbus, display
  • For ATEX applications, ignition protection Exd


Kobold TWL with thread-, flange- or weld-on connection measure temperatures of liquids, solids and gaseous media. The reliable watertight nature of these installation methods for gauge pressure and vacuum is an important criteria for selection. Applications are in air-conditioning and cooling, heating-, furnace-, mechanical- and apparatus- construction, as well as for industry in general.

For all applications in hazardous areas, the instruments are supplied with the ignition protection Exd.  Contact INSTROTECH for more information on Kobold’s TWL resistance thermometers on 010 595 1831 or



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