4
unable to maintain a low dew point, no matter what
drying method is used.
2.9.2 The Models 22000ST and 33000ST contain
a System Controller which maintains the correct
System Pressure over the full outlet capacity of the
dehydrator. The System Controller interrupts the
outlet air flow during a humidity alarm and bypasses
any surplus when the outlet air requirement is low.
2.9.3 The System Controller reacts to adjustment of
the System Regulator. A System Flow Val ve makes
it simple to obtain the full capacity of the dehydrator
without disconnecting the outlet air pipes.
2.10 WAT ER SYSTEM
2.10.1 It takes about two gallons of clean tap water
to prime and fill the dehydrator water system. Wa t er
is used to cool the compressor and acts to seal the
minute spaces between the port sleeve, the rotor and
the housing. This sealing action is possible because
of the high speed of the rotor. The water also acts
as a lubricant on the rotor seal that separates the
rotating rotor from the fixed housing. The fact that
the water is the medium between the assembled
parts together with a precise balance of mechanical
forces, are the major reasons for the exceptionally
long life of the compressor.
2.10.2 When air is compressed and then is cooled
for use in a dryer, it is usually at or near saturation
(100% relative humidity) regardless of the type of
compressor used. The saturated air is not a problem
to a well designed heatless desiccant dryer. Because
the heatless dryer purges air just as wet as the air
entering it, a balance is maintained over the designed
temperature and flow range.
2.10.3 The components in the water system which
require routine maintenance are the water filter, water
ejector solenoid valve and the water float switches
which are inside the Water Sight Tube.
2.10.4 A “Manual Water Eject Switch” has been
included in the water system to aid in maintenance
and in trouble shooting. The switch is visible when
the front cover is removed. The switch is clearly
labeled and is located on the left side above the air
intake filter.
2.11 OPTIONAL WAT ER CHILLER (P/N
101961 without flow control valve)
2.11.1 Both models may be equipped with a factory
installed “ Water Chiller”. This option is offered
for those sites where, due to building constraints,
adequate ventilation o r a i r conditioning are not practi-
cal alternatives and multiple dryers are required due
to very high air flow requirements. The necessary
coolant water flow may be provided by a recirculat-
ing cooled water system or by tap water.
2.11.2 The chiller option consists of an efficient flat
plate water-to-water heat exchanger, flow-orifice,
temperature indicator and related components. The
chiller coolant flow is regulated by the flow-orifice.
Termination of the chiller is at the rear of the dehy-
drator cabinet for easy hookup.
2.11.3 The dehydrator water circuit, (see paragraph
3.3), is kept totally isolated from the coolant water.
The warmest water in the dehydrator is cooled by
the chiller before it enters the dehydrators air cooled
heat exchanger and flows to the compressor. The
dehydrators operating environment thus is similar
to its environment when operating in a much cooler
room and its output capacity increases proportion-
ally.
3.0 DESCRIPTION OF OPERATION
3.1 Air/Water Flow System (see Fig. 2)
Ambient air is drawn through the inlet air filter and
through the Passive Air Intake, where it mixes with
purge air returning from the heatless dryer desic-
cant towers.
3.2 The combined wet air then enters the compres-
sors, where the pressure is raised to 28 PSIG and
the air is mixed with the compress or cooling water.
Water enters the compress ors at a rate control led by
the water metering orifices. The compressed air and
warmed water flows directly to the water separ ator
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