WIKA TW45 Mode D'emploi page 8

6. Commissioning, operation
It is recommended to mount the temperature measuring instrument into the thermowell using a
suitable sealing material to avoid, for example, humidity ingress.
In general, the tip of the thermowell should be placed in the middle third of the pipe, though
EN
the position may differ in special cases. It must be ensured that the measuring element (Pt100,
thermocouple, bimetal, etc.) is completely exposed to the medium and is not shielded by the
flange stubs. If, as a result of a small pipe diameter, this cannot be ensured, a pipe expansion can
be inserted around the measuring point.
Expansion of the pipe diameter from DN 40 to DN 80
Screw-fitting thermowells
When using parallel threads, a suitable seal should be used when mounting. Tapered threads
can be sealed by suitable seals or an additional welded seam. The correct tightening torques and
suitable tools (e.g. spanner) should be used.
Weld-fitting thermowells
Weld-in thermowells can be welded directly into the process (pipe or vessel wall) or by using a
welding socket. During weld-in operation, the requirements of the relevant material data sheets
and the applicable directives and standards must be considered regarding the heat treatment,
filler rods or welding procedures.
Thermowells with flange connection
The flange dimensions of the thermowell must match those of the mating flange on the process
side. The seals used must be suitable for the process and the flange geometries (consult the
delivery note). The correct tightening torques and suitable tools (e.g. spanner) should be used
for installation. For thermowells with a collar, make sure that it matches the inner diameter of the
coupling and is supported by it. In the case of an interference collar, they should be adapted to
the inner diameter of the coupling.
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WIKA operating instructions thermowells