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"Oil-Less" Scroll Laboratory Air
Appendix A: Desiccant Dryer
A.1 General Information
CAUTION: This manual is designed to serve as
the operation and maintenance guide for your
dryer, if equipped. The contents of this manual
should be carefully read BEFORE attempting any
phase of operation or maintenance. Failure to
follow the operating and maintenance procedures
of the instruction manual could result in personal
injury or property damage.
All information, specifi cations and illustrations
within this manual are those in eff ect at the time
of printing. The manufacturer reserves the right to
change or make improvements without notice and
without incurring any obligation to make changes
or add improvements to products previously sold.
When requesting information, service, ordering of
spare parts, etc., please reference all information
supplied on the serial number plate located on
the side of the control panel.
To facilitate maintenance, recommended spare
parts for your specifi c dryer model are available.
Failure to maintain recommended spare parts
and fi lter cartridges might result in expensive and
unnecessary downtime for which the manufacturer
cannot be responsible. To request a quotation of,
or place an order for, recommended or emergency
spare parts, please contact BeaconMedæs Service
at 1-888-4MEDGAS.
A.1.1 Drying Cycles
This fully automatic, heatless type dryer alternately
cycles the compressed, process gas fl ow through
two desiccant charged towers where the entrained,
vaporous moisture content of the gas is adsorbed.
One desiccant tower is always on-line in a drying
cycle throughout normal dryer operation. The
opposite, off -line tower is in a regeneration cycle
for removal of the previously adsorbed moisture
content or in a purge saving cycle at line pressure.
Manual Mode
When the dryer is in the "Manual" mode, the
dryer will shift towers every 30 seconds. At normal
operating conditions, one tower is at system
pressure and the other tower is at 0 p.s.i. Any
condition other than this is not normal and will
cause a high dew point condition. During tower
changeover, the online chamber will exhaust,
and the chamber that is regenerating (purging)
will come to line pressure. There is a fi ve second
re-pressurization cycle. If the dryer is in the
continuous purge cycle (Manual Mode), the dryer
will use 15% of the system capacity to purge the
dryer.
Automatic Mode
When the dryer is in the "Automatic" mode, the
dew point monitor controls the dryer purge, and
purging depends on the dew point condition.
When the dew point reading is above the setpoint
of -10ºC (14ºF), the dryer will function normally
(one tower at system pressure, one tower at 0
p.s.i.). When the dew point is below the setpoint
of -10ºC (14ºF), the purge valve will close. In this
condition both towers will be approximately 100
p.s.i. and the dryer will not shift towers until the
dew point is above -10ºC (14ºF).
A.1.2 Pre-fi lter
As the fi rst line of defense against water
contaminants, a coalescing pre-fi lter with an
automatic drain is installed. The coalescing pre-
fi lter removes water aerosols from the gas stream
before the gas enters the dryer. Liquids collected
by the assembly's fi lter cartridge(s) fall to the
housing sump and are drained by a fl oat drain.
Installer should pipe these drain connections to a
common drain point.
A-1
4107 9006 25.11
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