DE-18 USER MANUAL SECTION 4
36
4.4 AIR INLET SYSTEM,
FUNCTIONAL DESCRIPTION
Refer to Figure 4-2. The compressor inlet system
consists of a heavy duty two-stage, dry type air filter
mounted inside the canopy and connected to the
compressor and engine inlets via tubing and flexible
hose. In addition, stainless steel tubing from the air
filter housing to the control panel restriction switches
is provided.
A decrease in compressor inlet pressure, caused by
the collected airborne dirt, is sensed by the controller
and a filter maintenance announcement is displayed.
4.5 COMPRESSOR LOAD/
UNLOAD CAPACITY
CONTROL SYSTEM,
FUNCTIONAL DESCRIPTION
Refer to Figure 4-3. The purpose of the capacity
control system is to regulate the compressed air
supply to the demand. It consists of the inlet throttling
valve and blowdown subsystems integrated with the
controller. Primary modes of operation are described
below (for illustration purposes, 100 psig service
operation will be used):
DEFAULT STATES
Default states for the inlet valve and blowdown
subsystems are closed and fully open respectively.
The inlet control and blowdown control solenoids are
both de-energized in the closed state and energized
in the open state.
For the inlet valve subsystem, a closed or de-
energized inlet control solenoid, results in no
pressurized oil being applied to the hydraulic
actuator, and therefore the inlet butterfly valve is
closed, allowing a minimum amount of inlet air to
enter the compressor.
For the blowdown subsystem, a closed or de-
energized blowdown solenoid valve, means no pilot
air pressure is being routed to the pneumatic
blowdown valve, and therefore the blowdown valve is
open. The pneumatic blowdown valve uses a
mechanical spring to keep the valve open if pilot air is
not routed to the valve's diaphragm chamber. Once
the controller signals the blowdown solenoid to close,
LP pilot air is routed to the blowdown valve. Pilot air
pressure of 10 psig exceeds the mechanical spring
force, closing off the flow of HP discharge process air
to the blowdown silencer and atmosphere.
Figure 4-4: Silencing/Discharge Air and Cooling Systems
To Next Page
Loading...
