Commissioning, Operation - WIKA TW10-S Mode D'emploi

5. Transport, packaging and storage / 6. Commissioning, operation
5.3 Storage
Avoid exposure to the following factors:
Direct sunlight or proximity to hot objects (for thermowells with plastic coating)
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Mechanical vibration, mechanical shock (putting it down hard)
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WARNING!
Before storing the thermowell (following operation), remove any residual media. This
is of particular importance if the medium is hazardous to health, e.g. caustic, toxic,
carcinogenic, radioactive, etc.

6. Commissioning, operation

6.1 Mounting
During mounting the thermowells should not be subjected to thermal shocks or mechanical
impacts.
Insert the thermowell into the process adapter without forcing or damaging it. The thermowell
must not be bent or altered in order to mount it.
The exception is the retrospective machining of the support ring in order that the thermowell is
supported free of play within the nozzle ("interference fit"). The retrospective adjustment of a
support ring with a loose fit is not permissible. In general, thermowells with a support ring are not
recommended within ASME PTC 19.3 TW-2016 and are outside of the scope of the standard.
Mounting instructions for electrical thermometers with ceramic protection tube
Ceramic thermowell materials withstand changes in temperature only to a limited extent. A
temperature shock can therefore easily result in stress cracks and consequently in damage to the
protection tube.
For this reason, preheat thermocouples with ceramic or sapphire protection tubes before
installation, and then slowly immerse them into the hot process.
In accordance with DIN 43724, an insertion speed of 1 cm/min is recommended for protection
tubes with a diameter of 24/26 mm. For smaller diameters of 10/15 mm, the speed can be
increased to 50 cm/min. As a basic principle, higher process temperatures require a lower
insertion speed.
In addition to the protection from thermal stress, ceramic protection tubes must also be protected
from mechanical loads. The reason for these harmful stresses are bending forces in case of a
horizontal mounting position. As a consequence, an additional support must be provided in case
of a horizontal mounting position depending on the diameter, greater nominal lengths and the
design.
In principle, the deflection problem also occurs for metal protection tubes, particularly for
insertion lengths > 500 mm. For process temperatures > 1,200 °C, vertical mounting should be
preferred.
WIKA operating instructions thermowells
EN
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