Model 755A

Instruction Manual

245364-V May 2002

2-8 PURGE KIT (OPTIONAL)

NOTE:

The Purge Kit (PN 643108) is designed to equip the Model 755A with Type Z Air Purge per National Fire Protection Association Standard NFPA496-1986, Chapter 21.

WARNING

POSSIBLE EXPLOSION HAZARD

This analyzer is of the type capable of analysis of sample gases which may be flammable. If used for analysis of such gases, the instrument must be either in an explosion-proof enclosure suitable for the gas, or, protected by a continuous dilution purge system in accordance with Standard ANSI/NFPA-496 (Chapter 8) or IEC Publication 79-2-1983 (Section Three)

If explosive gases are introduced into this analyzer, the sample containment system must be carefully leak-checked upon installation and before initial start-up, during routine maintenance and any time the integrity of the sample containment system is broken, to ensure the system is in leak-proof condition.

Internal leaks resulting from failure to observe these precautions could result in an explosion causing death, personal injury and/or property damage.

The kit consists of the following:

PART NO. DESCRIPTION

190697 Purge Inlet Fitting

645835 Purge outlet Fitting

082787 Warning Label

856156 Sealant (Duxseal)

To conform to NFPA Type Z requirements, the warning label must be applied to the analyzer front cover. If the analyzer is ordered factory equipped with the Purge Kit, this label is applied at the factory.

Installation options are shown in Figure 2-8 (page 2-12). Use only clean dry air or suitable inert gas for the purge supply.

Recommended supply pressure is 20 psig (138 kPa), which provides a flow of approximately 8 cubic feet per hour (4 liters per minute) and a case pressure of approximately 0.2 inch of water (50 Pa).

With a flow rate of 4 liters per minute, four case volumes of purge gas pass through the case in 10 minutes.

All conduit connections through the case must be sealed thoroughly with the sealant supplied in the kit. The sealant (applied from the interior of the case) must thoroughly cover all existing leads, as well as the conduit fitting.

1These standards are not applicable to enclosures into which a flammable gas or vapor mixture is introduced, such as by a continuous sample containment system that is subject to accidental leakage.

Rosemount Analytical Inc. A Division of Emerson Process Management

Installation 2-11