Functional Verication
Since the analyzer operation is based on rst principles, analyzer calibration is
not required. This is fortunate because the preparation of a high-pressure gas
mixture with a known and stable dewpoint temperature is extremely dicult.
If a mixture is prepared and stored in a tank, the dewpoint temperature can
change as the gas is consumed. This is because for constant composition, the
dewpoint temperature is a strong function of the total pressure of the gas
mixture which decreases as the gas is consumed.
The use of dynamic saturation methods for preparing suitable mixtures with
a known dewpoint temperature is possible, but it is very time-consuming,
requires elaborate equipment, and demands extreme care in controlling the
pressure of the gas and the temperature of the saturator. Saturation methods
are not suitable for use outside a properly equipped laboratory.
However, the functionality of the analyzer can be checked by using a simple
procedure that relies upon the thermodynamic properties of a pure substance.
The success of the method only depends upon the purity of the substance and
the care with which the procedure is executed.
Propane, of laboratory or instrument grade, is the recommended substance for
checking the functionality of the analyzer.
Because propane is ammable, it must be disposed of through a
proper venting system.
PN 903-8797, Rev A
Functional Verication | 6-1
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