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Verifying the Analyzer
The verify process is used to correct for aging characteristics of the sen-
sor assembly and potential fouling of the sensor by components of the
sample stream. By measuring the response of the sensor to an internally
generated "moisture standard," any variations in sensor performance can
be effectively compensated for. During the verification operation, a new
span factor is calculated for the sensor, and this value is then applied for
all subsequent readings.
AMETEK recommends performing a verification cycle monthly.
However, no verification cycle should be performed during the startup
NOTE
of the analyzer. It is recommended to allow the analyzer and internal
moisture generator to stabilize for a period of 24 hours after applying
power, before running a verification cycle.
Changing Gasses
Selecting a different gas requires time for the analyzer to purge the inter-
nal volumes and stabilize flows. To prevent spurious alarms during the
transition, the analyzer will display New Gas on the display and automat-
ically purge itself. This period lasts forty minutes. The Data Valid contact
is opened during this period and flow alarms are suppressed. Note that
this process can be terminated by using the Abort function (Press the
Zero Key, scroll down to the Abort selection and press Enter). If Aborted,
normal sampling will resume after the completion of the current measure-
ment cycle.
Dew/Frost Point Measurements
Dew point values are calculated from the moisture concentration mea-
surements (PPMV) and the sample or process pressure. For temperatures
below 0 °C, the 5830 uses equations to determine the water vapor pres-
sure over ice, rather than over super-cooled water. Thus, the 5830 reports
a frost-point temperature consistent with the physical form of the con-
densed phase in a real process stream.
Water in super-cooled liquid state will only exist as a transient species,
as the first bit of condensate starts to form on a smooth-chilled surface
(i.e., the true method of measuring a dew point).
Given more time, the dew layer will turn to ice if the temperature is
below the freezing point.
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Overview
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