Chapter 5 Functional Verification - Ametek 241CE II Operator's Manual

FUNCTIONAL VERIFICATION
Since the analyzer operation is based on first principles, analyzer calibra-
tion is not required. This is fortunate because the preparation of a high-
pressure gas mixture with a known and stable dewpoint temperature
is extremely difficult. 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 con-
sumed.
The use of dynamic saturation methods for preparing suitable mixtures
with a known dewpoint temperature is possible, but it is very time-con-
suming, 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 sub-
stance for checking the functionality of the analyzer.
!
Because propane is flammable, it must be disposed of through a proper
venting system.
WARNING
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Functional Verification 5-1