Specifications

Heated Flame Ionization Detector Analyzer Module
Rosemount Analytical NGA 2000
748414-A
August 1999
1
INTRODUCTION
1
1.1 OVERVIEW
This manual describes the Heated Flame Ionization Detector (HFID) Analyzer Module of
Rosemount Analytical's NGA 2000 Series of gas analysis components. See Figures 1-1 and
1-2.
The HFID Analyzer Module is designed to continuously determine the concentration of
hydrocarbons in a flowing gaseous mixture at a user-selectable temperature setpoint
between 93°C and 204°C (200°F and 400°F). The concentration is expressed in ppm or
percent of volume.
The entire HFID Analyzer Module is designed as a stand-alone module, with gas
connections made from the rear. All electronics relative to sample detection and
conditioning are included in this module.
1.2 TYPICAL APPLICATIONS
The monitoring of atmospheric air for low-level hydrocarbon contaminants and determining
the hydrocarbon content of exhaust emissions from internal combustion engines are
examples of typical applications for the HFID Analyzer Module.
1.3 GAS SAFETY FEATURES
The HFID Analyzer Module is designed with a factory-installed continuous dilution purge
system in accordance with standard ANSI/NFPA 496 - 1993, Chapter 6. Front-panel LEDs
indicate that the burner flame is lit and that the purge system is enabled. In addition, fuel
gas is automatically shut off when a flame-out condition occurs or the safety system is
disabled.
The purge system is enabled only if there is proper purge gas flow in, purge gas pressure,
and internal case pressure, and after five times the case volume has been exchanged.
All tubing ahead of the burner is rigid metallic tubing assembled with ferrule/nut type
compression fittings. However, should an internal fuel leak occur, a worst-case leak would
be dissipated below 25% of the LEL of hydrogen through the combination of an inlet fuel
flow restrictor and purge gas flow.
This module is designed to use 40% H
2
/60% He fuel at a maximum inlet pressure of 3446
hPa-gauge (50 psig).