Commissioning, Operation - WIKA 990.27 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
■
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 diaphragm of the diaphragm seal must not be damaged. Scratches on the diaphragm
■
(e.g. from sharp-edged objects) are the main causes of corrosion.
Sealing of the process connection
■
- 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
■
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
■
elements of the order confirmation.
Prevention of temperature effects with differential pressure arrangements
■
Design and install the diaphragm seal measuring 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 measuring systems with capillary
By not observing the following assembly instructions, the capillary can become bent or it can
break. There is then a risk of leakage or a danger that the response time of the measuring
system will increase considerably.
Do not use the capillary for carrying the diaphragm seal measuring systems.
■
Use mechanical relief at the junction points of the capillary at the diaphragm seal and at
■
the measuring instrument.
Bending radius of the capillary ≥ 30 mm.
■
Attach the capillary free from vibration in order to prevent signal deviations.
■
WIKA operating instructions, diaphragm seal measuring systems
EN
13