Baker Hughes Panametrics Aurora H2O, Руководство пользователя

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7.5 No flow measurement indicated
on Aurora H2O measurement
cell outlet
Check to make sure that the outlet of the Aurora H2O
is venting to atmospheric pressure. Ensure that the
sample system valves are configured correctly and that
the Aurora H2O internal pressure regulator is capable of
a barely positive pressure setting. Check/replace the filter
element in the coalescer/filter as described in Chapter 6.
Maintenance on page 63.
7.6 Verifying Aurora H2O
performance in the field
There are two methods for verifying the performance of
the Aurora H2O in the field. The first method is to use a
portable hygrometer such as Panametrics’ PM880 portable
hygrometer. The second method is to use a moisture
generator or standard gas cylinder.
7.6.1 Using a portable hygrometer
One quick spot check that can be done, that is relatively
easy to do and requires minimal set-up time and no
consumables, is to use a second hygrometer. Panametrics
recommends using a PM880 portable hygrometer (see
Figure 99 below) for this purpose, with a recently calibrated
aluminum oxide moisture probe.
Figure 99: PM880 portable hygrometer
The PM880 can be connected to the outlet of the Aurora
H2O analyzer, using the portable sample system with the
aluminum oxide moisture probe, to verify the system. The
response time of the portable hygrometer is limited, as the
sensor is typically exposed to air during movement to the
sample point. So, it is recommended that the sample gas
remains flowing through the portable sample system on
the sample outlet of the Aurora H2O until equilibrium with
the moisture concentration of the sample gas is reached.
You can use the data-logging capability of the PM880 to
determine when steady-state conditions are reached.
Consult Panametrics if you have application questions
regarding this process.
7.6.2 Using a moisture standard
The best moisture standard to use is one generated by a
moisture generator as a flowing reference, due to the fact
that static moisture standards in cylinders have limited
capability and reliability. A moisture generator such as
Panametrics’ MG101 moisture generator (see Figure 100
below) can be used for this purpose.
Figure 100: MG101 moisture generator
However, a moisture generator is typically used only in an
indoor location with reasonably good temperature control.
In the field this is not always practical, so a more convenient
option would be to use a static moisture standard in a gas
cylinder. Consult with your local specialty gas supplier about
standards for moisture. Based on application experience,
Panametrics recommends the following guidelines
regarding moisture standards in gas cylinders:
• Use passivated, aluminum gas cylinders only.
• Do not use the cylinder when the pressure falls below 50%
of the original pressure supplied by the vendor (typically
1500-1800psig).
• Use the gas cylinder for moisture values of 50–100 ppm.
• Use a moisture standard having a background gas of
nitrogen (N2).
• Mix the moisture standard for 10 minutes prior to use,
following the manufacturer’s guidelines (rolling the
cylinder is typical).
• Use the gas cylinder at the nominal temperature at which
the cylinder was tested by the manufacturer.
Whether using a moisture generator or a standard moisture
gas cylinder, the source gas should be connected to the
Aurora H2O using the PURGE INLET on the analyzer. Ensure
that the sample gas pressure is regulated to a just barely
positive pressure and establish gas flow from the purge inlet
to the Aurora H2O measurement cell.
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