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Instruction Manual
748297-E
June 2003
Installation Rosemount Analytical Inc. A Division of Emerson Process Management
2-4
Model NGA2000 HFID
introduced through the sample inlet at the
rear of the module.
Zero Gas - Analysis is affected by the
background gas of the sample. Therefore, it
is recommended to use zero gas with as
close to the background composition of the
sample as possible. Normally less than 0.5
THC as CH
4
is sufficient.
Span Gas - Span gas consists of a speci-
fied concentration of methane or other hy-
drocarbon in a background gas such as
nitrogen. Analysis is affected by the back-
ground gas of the sample. Therefore, span
gas containing the same background gas as
the sample is recommended. Then, the
background effect is canceled out.
h. Sample Gas Specification
Sample gas should be nonflammable (be-
low 100% of the sample's LEL). For high
sensitivity applications requiring background
gas compensation, contact the factory.
i. Flow Rate Specification
Required sample flow rate is 1.0 L/min. to
2.5 L/min. for a supply pressure between 5
and 9 psig. Flow rate for purge gas should
be 16 to 18 L/min. Flow rate for regulated
air should be 2 to 4 L/min.
j. Pressure/Filtration Specification
Sample Pressure at the SAMPLE inlet
should be within the range of 345 to 620
hPa-gauge (5 to 9 psig, 7.0 psig nominal),
and internally, should be between 206.7
and 275.6 hPa-gauge (3.0 and 4.0 psig).
Burner Fuel Pressure should be: 3101 to
3450 hPa-gauge (45 to 50 psig) for cylinder
regulator, 1723 hPa-gauge (25 psig)
nominal for internal pressure.
Burner Air Pressure should be : 1725
to 3450 hPa-gauge (25 to 50 psig) for
cylinder regulator, 1035 hPa-gauge (15
psig) nominal for internal pressure.
Regulated Air Pressure should be 689
to 1725 hPa-gauge (10 to 25 psig) for
cylinder regulator.
Purge Air Pressure should be 689 to
1380 hPa-gauge (10 to 20 psig).
Nominal Internal Case Pressure is
about 0.5 to 1.0 inch of water, and the
pressure relief valve is set at 1/3 psig
(nominal).
CAUTION
OVER-PRESSURE
Noncompliance with these specifica-
tions, particularly those concerning
purge air, could cause over-pressure
damage to the module.
Note
The sample gas and regulated air
should be filtered for particulates
down to 2 microns to prevent the
plugging of pneumatic components.
k. Leak Test
The analyzer module is completely leak
tested at the factory. The user is re-
sponsible for testing for leakage at the
inlet and outlet fittings on the rear panel.
The user is also responsible for internal
leak testing periodically and if any inter-
nal pneumatic components are adjusted
or replaced (with a test procedure cho-
sen by the user).