Emerson Process Management NGA2000 HFID Manual Do Utilizador

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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