Model NGA 2000 HFID

Instruction Manual

760004-A February 2002

b.Pneumatic Connections

WARNING

HIGH TEMPERATURES

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 module is powered down.

(See Figure 2-1) Connect inlet and outlet lines for sample, burner fuel and air, ex- haust, bypass, regulated air, and purge to appropriately labeled fittings on the rear panel. All connections are 1/4-inch ferrule -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 interconnection 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 Mod- ule, as installed, are not visible, the user should provide an indicator for the safety system as per ANSI/NFPA 496 standards.

c.SpecificationsFuel Gas

Standard analysis usually requires mixed fuel, i.e., 40% ±2%) hydrogen and 60% helium. H2/He mixed fuel is recommended over H2/N2 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.

Burner Air

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 CALIBRATION GASES below) is a combination diaphragm pump and heated palladium catalyst. This process continuously removes moderate amounts of hydrocarbons and carbon monoxide from ambient air.

Purge Air

Instrument quality air or nitrogen is required for the safety purge system.

Regulated Air

Instrument quality air or nitrogen is re- quired. The air should contain less than 2 ppm maximum total hydrocarbon content.

Calibration Gases

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

Rosemount Analytical Inc. A Division of Emerson Process Management

Description and Specifications

2-3