42/24-12-2 EN
Advance Optima Ex Analyzer Modules Operator’s Manual
27
Inspection and Maintenance
F
Follow
•
the instructions and notes in the "Inspection and Maintenance" chapter of
Operator’s Manual 42/24-10 EN,
•
the following special instructions and notes as well as
•
the notes in the "Electrical Equipment in Explosion Hazard Zones" sections in
the Annex.
Inspection
Regularly verify that all parts of the housing are fully tightened and secured with
set screws.
Caldos 17-Ex
Uras 14-Ex
Make sure that, on horizontally mounted units, the O-rings between the housing
bottom and housing as well as between the housing and housing cover are in the
appropriate slots, clean and not crushed.
Check Gas Path Seal
Integrity
Sample gas path seal integrity should be examined during operation at least once
annually.
A sample gas path leak is the probable cause if any of the following conditions
occur:
•
Erratic measurement readings (e.g. after starting the test gas supply)
•
Implausible values
•
"Drift" or "Calibration not possible" error messages during calibration
A simple procedure for checking gas path seal integrity is described in the "Check
Gas Path Seal Integrity" section (Page 11).
Measures taken after
opening the gas
paths inside an Ex
analyzer module
•
All parts of the housing are fully tightened and secured with set screws?
•
If the sample or reference gas path inside an Ex analyzer module has been
opened, the seal integrity should be tested with helium at a leak rate of
< 2 x 10
-4
hPa l/s.
The pressure drop method, described in the "Check Gas Path Seal Integrity"
section can be used as an alternative to the helium test. To accomplish this,
increase the test pressure to a p
e
of approx. 400 hPa (= 400 mbar) and increase
the test period to 15 minutes. The maximum excess pressure p
e
= 500 hPa
(= 500 mbar).
•
Any time the gas paths are opened they must then be purged prior to connecting
the 24 VDC power supply. This should remove any explosive gas/air mixture in
the gas paths.
Purge gas
For a non-combustible sample gas: Clean instrument air from
areas free of any explosion risk
For a combustible sample gas: Inert gas
Purge gas qty
5 times the volume of the gas paths
Purge gas flow
Approx. 30 l/h
Purge duration
At least 3 minutes
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