Climate Control Series
Quincy Compressor
2022209100, August 2018
7
•Principles of Cooling System
Fan blades in the compressor sheave force ambient air across fins on the cylin-
der heads (and intercooler fins of two stage compres sors). Quincy compressors
should be operated in temperatures under 104°F.
Principles of Dryers & Filters
Moisture occurs naturally in air lines as a result of compression. Moisture
vapor in ambient air is concentrated when pressurized and condenses when
cooled in downstream air piping. Compressed air dryers reduce the moisture
vapor concentration and prevent water formation in compressed air lines.
Dryers are a recommended companion to filters, aftercoolers, and automatic
drains for improving the productivity of compressed air systems.
Water and moisture vapor removal increases the efficiency of air operated
equipment, reduces contamination and rusting, increases the service life of
pneumatic equipment and tools, prevents air line freeze-ups, and reduces
product rejects.
•Principles of Control System
Simplex Units
Simplex Climate Control units are controlled by a pressure switch which
detects the demand for compressed air and allows the motor to start. When
the demand is satisfied, the unit stops.
Duplex Units
Duplex Climate Control units are controlled by multiple pres sure switches
(one for each compressor). They react to a demand for air the same way as a
simplex unit. In addition to the pressure switches, duplex units can be con-
trolled by an electrical alternating switch that automatically distributes the
workload evenly between the two basic compressors. The following example
best explains the process:
The lead compressor starts and runs to satisfy the air demand. When the
pressure in the system reaches the cut-out pressure of the lead compressor, it
shuts off. The next time air is required, the lag compressor starts up first and
becomes the lead compressor.
If the lead compressor can not satisfy the air demand, the lag compressor
will automatically start and assist until the pressure in the system reaches
the cut-out pressure. At the cut-out pressure, both the lead compressor and
lag compressor shut down. The cut-in pressure of the lead pressure switch is
normally set 10 PSIG higher than the lag pressure switch.