Emerson Rosemount 370XA, Справочное руководство системы

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System Reference Manual 370XA Gas Chromatograph
7P00370-H01 APRIL 2014
3 - 30
To avoid this hydrocarbon condensation, heat the regulator and
sample lines to the gas chromatograph to at least 30 °F (17 °C) above
the expected temperature of the flowing gas stream.
Use stainless steel tubing and fittings for all of the sample lines. Use
Teflon tape when making threaded connections in the sample system.
Do not use pipe thread compounds.
Once the sample is extracted, the gas should pass through both a 2-
micron particulate filter and a liquid filter/shut-off to remove any
remaining contaminants before it enters the gas chromatograph.
CAUTION
If the sample system does not contain a 2-micron filter and a liquid filter/shut-off, the
GC’s warranty may be void if it is determined the failure is due to contamination.
NOTICE
All sample conditioning systems sold with the 370XA include a 2-micron filter for
each stream, and a liquid filter/shut-off can also be purchased separately for each
stream.
Observe the following guidelines for installing sample lines:
• Line Length
If possible, avoid long sample lines. In case of a long sample
line, flow velocity can be increased by increasing the sample
pressure and by using by-pass flow via a speed loop.
• Sample Line Tubing Material
Ensure tubing is clean and free of grease.
• Dryers and Filters
-
Use small sizes to minimize time lag and prevent back
diffusion.
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Install a minimum of one filter to remove solid particles. Most
applications require fine-element filters upstream of the GC.
The recommended sampling system includes a 2-micron filter.
-
Use ceramic or porous metallic type filters. Do not use cork or
felt filters.