Commissioning, Operation - WIKA ISO 9001 Mode D'emploi

5. Commissioning, operation

5. Commissioning, operation
5.1 General mounting instructions
Sealed screws on the diaphragm seal or measuring instrument must not be loosened
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under any circumstances. Otherwise there is a risk that the system fill fluid may escape,
with the result that the measuring assembly may not function correctly anymore.
The sensitive diaphragm of the diaphragm seal must not be damaged; therefore, avoid
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any contact or mechanical loading. Scratches on the diaphragm (e.g. from sharp-edged
objects) are the main causes of corrosion.
With in-line diaphragm seals, the internal diaphragm surface must not be used for mount-
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ing purposes.
Sealing of the process connection
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- Select suitable sealing for the respective application and diaphragm seal version.
- Use flange sealing with sufficiently large inner diameter.
- Centre sealing on the sealing face.
- The diaphragm movement must not be limited due to the sealing.
When using soft or PTFE sealings, observe the instructions of the sealing manufacturer,
particularly with regard to tightening torque and load cycles.
For installation, in accordance with the fitting and flange standards the appropriate
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fastenings, such as screws and nuts, must be used. Mount these with the prescribed
tightening torque.
Observe the permissible medium and ambient temperatures. These are constituent
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elements of the order confirmation.
Prevention of temperature effects with differential pressure arrangements.
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Design and install the diaphragm seal system so that the plus and minus side have as
similar ambient temperatures as possible. The greater the difference is between the plus
and minus side, the higher will the measuring inaccuracy due to the temperature effect be.
5.2 Mounting instructions for diaphragm seal systems with capillary
By not observing the following assembly instructions, the capillary can become bent or it
can break. Bent capillaries will result in a considerably increased response time. In the worst
case, bending will lead to a capillary break, so that the system fill fluid can escape and the
diaphragm seal system cannot be commissioned anymore.
Do not use the capillary for carrying the diaphragm seal systems.
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Use mechanical relief at the junction points of the capillary at the diaphragm seal and at
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the measuring instrument.
Bending radius of the capillary ≥ 30 mm.
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Attach the capillary free from vibration in order to prevent signal deviations.
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WIKA operating instructions, diaphragm seal systems
EN
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