Endress+Hauser Deltabar S PMD70 Austauschanleitung Seite 8

KA603P/00/a2/12.06
Disassemble of sensor unit
Hints for exchanging a sensor Deltabar S
After opening and installation of a sensor assembly, the technical characteristics will be outside the specifications, the instrument will
measure with slightly reduced accuracy.
The reason is a lack of conditions available in normal production, such as controlled temperature, adjusted air pressure,
humidity, etc. The specifications shown in technical data sheets can therefore only be accomplished in the regular manufacturing process.
The cause is the clamping and suitable bolt down of the measuring cell between the side flanges. Design related, this affects mainly metal
measuring cells in all available ranges. Therefore, it is recommended to have all repairs and exchanges related to the sensor assembly only be
performed in the factory, or at least to order and use pre-calibrated complete sensor assemblies.
Nevertheless, an exchange of the sensor assembly is possible, following the recommendations below to minimize the measured error
( error factors see table, page 5
Replacing a ceramic measuring cell:
1 Loosen the four flange bolts and remove the flanges.
2
Lift out the measuring cell, unplug the cable and remove the centering ring.
3 Remove the sealing rings from the flanges and clean the flange inner surfaces (free of dust and grease).
It is essential to have a maximum cleanliness on the sealing surfaces, n
4
The process gaskets (sealing rings) must be cleaned carefully (absolutely free of dust and lint) and be inserted into the sealing grooves
of the side flanges (for Oxygen applications, exchange sensors are only available as complete assemblies).
5
Slide the centering ring on the measuring cell and reattach the plug connector of the cell to the electronics
Assembly of sensor unit
• Place the new measuring cell in the flange (minus part), so that the sealing rings are not pushed out of position and that the cable to the
electronics is not squashed. The original assembled state ensures that the positive and negative lower pressure sides of the measuring
cell are correctly allocated. Additionally there is a tag C1 and C2 on the side of the sensor.
C1 marks the plus-side and C2 marks the minus-side for the differential pressure.
• Attach the counter flange carefully so that the inner sealing rings do not slide out of position.
• Before they are bolted down, the flanges must be clamped t
Fasten the screws diagonal fashion so that the flanges and sealing rings press equally on the membrane sides of the ceramic body sensor.
The four screws must be tightened with a torque spanner of 30 Nm.
• Secure the screwed connection with lacquer.
2
).
1
flange
3
"+ side"
5
"+ side" ceramic
measuring cell
with centering ring
Exchange of sensor unit on Deltabar S PMD70
4
2
ceramic
measuring cell
centering
ring
o sealing surface may be damaged and show any marks or dents.
ogether, they must contact each other (
constant air
flange
1
"- side"
.
i.e. with a screw clamp)
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