Ametek Thermox WDG-V, User Manual

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3-28 | Thermox WDG-V / VC / VCM with Blow Back
Notes About Ducting
Ducting Between Pressurized Enclosure and Inlet
The intake ducting to a compressor should not normally pass through a
hazardous area. If the compressor intake line passes through a hazardous
area, it should be constructed of non-combustible material and protected
against mechanical damage and corrosion. Adequate precautions should
be taken to ensure that the ducting is free from leaks in case the internal
pressure is below that of the external atmosphere (see Annex C). Addi-
tional protective measures, for example, combustible gas detectors, should
be considered to ensure that the ducting is free of flammable concentra-
tions of gas vapor.
Additional Purge Time to Account for Ducting
The purge duration should be increased by the time necessary to purge
the free volume of those associated ducts which are not part of the equip-
ment by at least five times their volume at the minimum flow rate speci-
fied by the manufacturer.
Power for Protective Gas Supply
The electrical power for the protective gas supply (blower, compressor,
etc.) should be either taken from a separate power source or taken from
the supply side of the electrical isolator for the pressurized enclosure.
Enclosure Maximum Overpressure
The user should limit the pressure as specified by the manufacturer.