Thermowells are metallic sockets generally consisting of 3 main parts: assembly hexagon, process connection and immersion tube.

Thermowells are used to separate the thermometer bulb or temperature probe from the media in order to avoid a possible corrosive effect of the stem, as well as to protect them from working pressure and from the possible high speed flow rate. Thermowells also allow the inspection of the instruments in case of maintenance and replacement without disturbing or stopping the process, avoiding possible fluid leaks in order to safeguard the system, the environment and the operator.


Highlighted the parts and the most important definitions of thermowells


Materials are generally chosen taking care of corrosion resistance from media. Apart from this also the knowledge of the specific industry regulations are important to avoid the migration factor, for example as FOOD sector.
All materials have polish finishing to confer to the thermowells highest level of resistance to the corrosion and to avoid any bacterial charges given by the fluids sediments.


This is the material part between the assembly hexagon and the process connection. It’s meant to distance the in- strument from the process.

Immersion length:

It’s the length of tube between the tip and the connection process. Has the purpose of being insert in the media.

Process connection:

Thermowells may have a wide range of process connections:


Standard thread ( GAS UNI-338 BSP)


DIN 11851 connections, liner + nut or thread part ( SANITARY CONNECTIONS)


Special connections for specifically application or welding thermowells without any connections


ASME flanged connections


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