WIKA TW22 Mode D'emploi page 10

6. Commissioning, operation
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.
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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, applicable directives and standards as well as the thermowell data sheets
must be considered regarding the location of the welding connection as well as 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.
Due to the risk of crevice corrosion, the screw-welded model TW10-S is not suitable for use
in aqueous media.
Irrespective of the process connection, 3 mounting positions of thermowells in pipes are
possible:
Right-angled position with respect to the flow (most unfavourable position)
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10 WIKA operating instructions thermowells