WIKA Protection Tube (TW81)

Version per DIN 43734 (EN 50446)


  • Blast furnaces, air heaters
  • Heat threatment furnaces
  • Waste incineration plants
  • Major heating plants, heat generation

Special features

  • Variable length and dimensions
  • Large selection of materials
  • Different process connections

Sales Contact (Wika.sales@asyatrafo.com)




Each protection tube or thermowell is an important component of any temperature measuring point. It is used to separate the process from the surrounding area, thus protecting the environment and operating personnel and keeps aggressive media, high pressures and flow rates from the temperature sensor itself and thereby enables the thermometer to be exchanged during operation.

Based on the almost limitless application possibilities, there are a large number of variants, such as designs or materials. The type of process connection and the basic method of manufacture are important design differentiation criteria. A basic differentiation can be made between threaded and weld-in protection tubes, and those with flange connections.

The bottom of protection tube model TW81 is either flat or dished, in the case of enamelled protection tubes it is always dished. The protection tube is plugged into the connection head and compression fitted. Additionally, we offer the WIKA data sheet TW 95.81 possibility of a connection head screwed at the protection tube. This allows an ingress protection IP65. A slideable process connection is compression fitted on the protection tube, thus allowing a variable insertion length.

Preference is to be given to standard nominal lengths per EN 50446.