Maintenance 119
Checking the Seal Integrity of the Sample Gas Feed Path
When should the seal integrity of the sample gas feed path be checked?
The seal integrity of the sample gas feed path should be checked
regularly.
We recommend that the seal integrity of the sample gas feed path is
checked before commissioning (see page 94) the instrument at the
inst
allation site, since it may have been affected during transport of the
gas analyzer (e.g. through strong vibrations).
The seal integrity of the sample gas feed path must always be checked
after the sample gas feed path inside the gas analyzer has been opened
(see page 120).
Requisite Material
Pressure gauge
Flexible tubing, length approx. 1 m
T-piece with shut-off valve
Air or nitrogen
ATTENTION
If the seal integrity test is to be carried out with air and if flammable gas
could be present in the sample gas feed path or is to be subsequently
introduced, the sample gas feed path must be purged with nitrogen
beforehand! The seal integrity test can be carried out with nitrogen
instead.
Checking the Seal Integrity of the Sample Gas Feed Path
1 Seal the sample gas outlet so that it is gas-tight.
2 Connect the T-piece with the shut-off valve to the sample gas inlet by
means of the flexible tubing.
3 Connect the free end of the T-piece to the pressure gauge.
4 Blow air or nitrogen through the shut-off valve until the sample gas
feed path is under a positive pressure of approx. 50 hPa. Maximum
positive pressure = 150 hPa.
5 Close the shutoff valve. The pressure should not change measurably
in 3 minutes. A sharp drop in pressure indicates a leak in the sample
gas feed path.
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