ABB AO2000 Series, Руководство по эксплуатации

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68 AO2000 CONTINUOUS GAS ANALYZERS | OI/AO2000-EN REV. B
Associated gas effect
Inert gases (Ar, N
2
) have no effect. Flammable gases (CO, H
2
, CH
4
) in stoi-
chiometric concentrations for the oxygen content: Conversion of O
2
< 20 %
of the stoichiometric conversion. If there are higher concentrations of
flammable gas, higher O
2
conversion rates must be expected.
Sample gas outlet conditions
The outlet pressure must be the same as the atmospheric pressure.
Test gases
Reference point (= electrical zero)
Clean ambient air; its oxygen concentration can be calculated from the value
for dry air and the factor for the consideration of the water vapor content.
Example:
Water vapor content at 25 °C and 50 % relative humidity = 1.56 vol.% of H
2
O
 factor 0.98
Oxygen concentration = 20.93 vol.% of O
2
×
0.98 = 20.6 vol.% of O
2
End point
Test gas with oxygen concentration in the smallest measurement range (e.g.
2 ppm O
2
in N
2
)
NOTES
The pressure conditions at reference point and end point must be identical.
Notes for checking the reference point and end point (see page 263) must be
considered.
Purge gas
If a housing purge is selected (only in IP54 version), purging may only be
carried out with air (not with nitrogen) as the ambient air serves as a refer-
ence gas.
Gas connections
see section "ZO23: Gas connections" (see page 95)
Installation and sample conditioning
ATTENTION
The ingress of liquids into the analyzer module can cause serious damage
including destruction of the sample cell.
NOTE
The following information on installation and the sample conditioning must
be considered for the measurement and the execution of controlled calibra-
tions (manual, automatic and externally controlled calibration). Manually
operated cocks and valves must be replaced by controlled valves suitable for
the oxygen trace measurement, as required.