Ingersoll-Rand 100-200 HP/75-160 KW - Manual (Page 43)

5.4 COMPRESSED AIR SYSTEM
The air system is composed of:
1) Inlet air filter
2) Inlet valve/stepper motor
3) Rotors
4) Coolant/air separator
5) Minimum pressure/check valve
6) Aftercooler
7) Moisture separator/drain trap
Air enters the compressor, passing through the inlet air
filter and butterfly inlet valve.
Compression in the screw-type air compressor is created
by the meshing of two helical rotors (male and female) on
parallel shafts, enclosed in a heavy-duty cast iron
housing, with air inlet and outlet ports located on
opposite ends. The grooves of the female rotor mesh
with, and are driven by, the male rotor. Tapered roller
bearings at the discharge end prevent axial movement of
the rotors.
The air-coolant mixture discharges from the compressor
thru a discharge check valve into the separation system.
This system, self-contained in the separator tank,
removes all but a few PPM of the coolant from the
discharge air. The coolant is returned to the system and
the air passes to the aftercooler. The aftercooling system
consists of a heat exchanger, a condensate separator,
and a drain trap. By cooling the discharge air, much of
the water vapor naturally contained in the air is
condensed and eliminated from the downstream
plant-piping and equipment.
During unloaded operation, the butterfly inlet valve
closes, via stepper motor, and the blowdown solenoid
valve opens, expelling any compressed air back to the
compressor inlet.
5.5 COOLANT/AIR SEPARATION SYSTEM
The coolant/air separation system is composed of a
separator with specially designed internals, a two-stage
coalescing-type separator-element, and provision for
return of the separated fluid back to the compressor.
Internal baffles maintain the circumferential flow of
remaining coolant droplets and air. In an almost
continuous change of direction of flow, more and more
droplets are removed from the air by inertial action and
then returned to the sump.
The air stream, now essentially a very fine mist, is
directed to the separator element.
The separator element is constructed with two
concentric, cylindrical sections of closely packed fibers,
each held in steel mesh. It is flange-mounted at the
separator-outlet-cover.
The air stream enters the separator element radially
and the mist coalesces to form droplets. The droplets
collected on the outer first stage fall to the separator
sump. Those collected on the inner second stage
collect near the outlet of the element, and are drawn
back to the compressor inlet through a filter-screen and
orifice fitting installed in the separator scavenge line.
The air stream, now essentially free of coolant, flows
from the separator to the aftercooler, then to the
condensate separator, and on to the plant air system.
5.6 ELECTRICAL SYSTEM
The electrical system of each SSR compressor is built
around the microprocessor-based Intellisys controller.
The standard electrical/electronic components,
enclosed in a readily accessible enclosure include:
1) IntelIisys controller
2) Compressor motor starter, with auxiliary contacts
and overload relays
3) Cooling fan motor overload relays and circuit
breaker or fuses
4) Intellisys Power Supply Board
5) Control transformer and fuses
Options, such as power outage restart can be enabled
by installing plug-in (option) modules in the Intellisys
controller.
OPERATION
The coolant and air discharging from the compressor
flow into the separator through a tangential discharge
outlet. This outlet directs the mixture along the inner
circumference of the separator, allowing the coolant
stream to collect and drop to the separator sump.
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