24431
Rev. A
10/12
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Environmental Technology, Inc.
12 of 94
Automatic Air Dehydrator
ADH
®
SIROCCO™
Instruction Manual
DEHYDRATION SYSTEM
The ADH Sirocco is a low pressure automatic air dehydrator. Low pressure air
provides personnel and equipment safety along with energy efficiency. Activated
alumina is used as the drying agent. Alumina, or aluminum oxide, is an energy
efficient desiccant with a long life expectancy.
Air is dehydrated by passing it through one of two drying canisters containing the
drying agent. Dry air is delivered to the communications equipment through a
connection in the rear panel. The moisture is removed from the drying canisters
by heat. The default configuration provides dry air at 0.5 psig (34.5mbar) and is
capable of delivering 26 cubic feet of air per hour (12.3 liters per minute).
Two drying canisters provide a continuous supply of dry air. One unit is active
while the other is maintained in stand-by or being regenerated. Under normal
circumstances, the dew point of the air is nominally -70°C, with a maximum value
of -40°C. The unit operates on one canister for a pre-determined length of time,
after which, the stand-by drying canister is brought into service and the used
canister is regenerated. The drying canister being regenerated is heated
internally until a temperature is attained which will convert all absorbed water into
steam. The resulting vapor is purged by pumping ambient air through the drying
canister and collecting the water in an evaporator where it is again heated and
driven off as water vapor. No drain line or special ventilation is needed.
PRESSURIZATION
The single-diaphragm compressor features a brushless motor with a 15+ year life
expectancy. It provides a maximum unrestricted flow rate of 6 lpm (12.7cfh).
The discharge pressure cycles between two limits. These limits are user-
configurable in a range between 0.20 psig and 7.50 psig (13.8mbar - 57mbar).
Additional information regarding user-configurable settings is provided later in
this manual. A safety relief valve operates at 8 psig (552mbar) to provide over-
pressure protection for the compressor.
A solid state pressure transducer senses discharge pressure. The transducer’s
signal is digitized and processed to control the compressor. The compressor
comes on when the pressure reaches the Minimum Pressure (Low Limit Target
Pressure) and shuts off at the Maximum Pressure (High Limit Target Pressure).
Note: If the temperature inside the unit is measured at less than 32°F (0°C), the
dehydrator will not turn the compressor on.