Emerson Process Management ROSEMOUNT NGA2000 HFID - Manual (Page 23)

Instruction Manual
748297-E
June 2003
Rosemount Analytical Inc. A Division of Emerson Process Management Installation 2-3
Model NGA2000 HFID
b. Pneumatic Connections
WARNING
HIGH TEMPERATURE
The Sample In, Sample Bypass Out, and
Burner Exhaust Out gases and fittings
can reach temperatures of up to 250
°C.
Make connections to these fittings when
the oven heater is disabled or the mod-
ule is powered down.
(See Figure 2-1 on page 2-2) Connect inlet
and outlet lines for sample, burner fuel and
air, exhaust, bypass, regulated air, and
purge to appropriately labeled fittings on the
rear panel. All connections are 1/4-inch fer-
rule-type compression fittings except the
PURGE AIR IN and OUT connections,
which are 3/8-inch compression fittings. The
Burner Exhaust is a 3/8-inch connection.
It is recommended that no connection be
made to the PURGE AIR OUT port. If, how-
ever, the analyzer's location requires inter-
connection with a venting system, the 3/8"
O.D. line should be kept as short as possi-
ble, and no longer than four feet.
CAUTION
POSSIBLE INSTRUMENT DAMAGE
No connection should be made to the
PRESSURE RELIEF VALVE fitting. Doing
so may cause damage to the instrument.
CAUTION
PURGE AIR REQUIREMENTS
The front panel LEDs of the Analyzer
Module, as installed, are not visible, the
user should provide an indicator for the
safety system as per ANSI/NFPA 496
standards.
c. Fuel Gas Specification
Standard analysis usually requires
mixed fuel, i.e., 40% ±2%) hydrogen
and 60% helium. H
2/ He mixed fuel is
recommended over H 2 /N 2 fuel because
of better linearity in concentration out-
put. Such blends are supplied by many
gas vendors specifically for this use,
with a guaranteed maximum total hy-
drocarbon content of 0.5 ppm, meas-
ured as methane. This specification
should be used when obtaining these
mixtures.
Note
The fuel restrictor is marked with a
red dot, and the sample capillary is
marked with a red or green dot for
mixed fuel applications.
d. Burner Air Specification
In order to ensure a low background
signal, burner air should contain less
than 1 ppm maximum total hydrocarbon
content. An alternate source for burner
air and zero gas (see Section 2-4g
below) is a combination diaphragm
pump and heated palladium catalyst.
This process continuously removes
moderate amounts of hydrocarbons and
carbon monoxide from ambient air.
e. Purge Air Specification
Instrument quality air or nitrogen is re-
quired for the safety purge system.
f. Regulated Air Specification
Instrument quality air or nitrogen is re-
quired. The air should contain less than
2 ppm maximum total hydrocarbon con-
tent.
g. Calibration Gases Specification
Calibration method and gases depend
on the operating range, and the desired
measurement accuracy. In all methods,
zero and span gases are used, and are