Servomex 07931001B, Operator'S Manual

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© Servomex Group Limited. 2020 07931001B revision 6
Enclosure environmental / measurement (instrument) purge
Make sure that you vent purge gases carefully to avoid creating a hazard.
If using toxic, asphyxiant or flammable sample or calibration gases,
always purge the enclosures with non-hazardous gas during operation to
reduce the risk of hazardous concentrations accumulating within the
analyzer. Purge the enclosures for a suitable time before opening to
ensure any concentrations are reduced to safe levels. Open transmitter
or receiver enclosures in a force ventilated open area, or in another
appropriate environment in which any hazardous gases are directed
away from the user.
Make sure that the vent for environmental / measurement (Instrument)
purge gas is clear and unobstructed so that the Laser 3 Plus enclosure
does not become pressurized or its IP rating compromised.
Ensure the pressure of the measurement purge exceeds the pressure of
the environmental purge gas to avoid backflow.
If the purge delivery system cannot be flow limited, the performance of
the analyzer may be degraded and the equipment may be physically
damaged.
For applications where purging of the transmitter and receiver units is required for
measurement or cooling, you must make sure that the direction of flow is as shown
in Figure 7-22: Transmitter purge and Figure 7-23: Receiver purge.
The transmitter and receiver units have internal optical surfaces. The purge gas
must be clean, and you may need to add additional filtering. Use Nitrogen or other
non-hazardous gas as a purge gas. Make sure that the purge flow is less than
0.1 liters/minute (0.004 cubic ft/min) to avoid pressure build up inside the units.
Note: In ambient environments where dew points may exceed 15°C, Servomex
recommends the use of measurement and environmental purge with dp <15°C
for the Transmitter unit (Ident 6 in Figure 7-22) in order to prevent condensation.
Note: Some instrument air may contain small amounts of oil and water which will
quickly damage the optical windows, mirrors and lens in the receiver and
transmitter units. Ensure proper precautions are taken to avoid this.