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COMPONENT DESCRIPTION
3.7.2 INLET CONTROL VALVE
The inlet control valve is the main control for air capacity within the air compressor. It is equipped with
a poppet disc
for inlet control as well as reverse flow check. The valve is initially opened at start-up by
suction created by rotating screws in the compressor unit. An air signal from the pressure regulating
control valve will modulate the poppet disc when air demand is low. Upon shutdown, the poppet disc
closes
to eliminate reverse airflow from the compressor to prevent the compressor unit from turning back
-
wards. The inlet valve is mounted directly to the compressor unit inlet.
3.7.3 PRESSURE REGULATING CONTROL VALVE
The pressure regulating control valve modulates the inlet valve to match incoming air with output air
demand. The valve is normally closed. It will open when the line pressure rises to the adjustable set point.
As the pressure regulating control valve opens, an air signal is sent to modulate the inlet valve. The pres-
sure regulating control valve is located behind the front left access door panel.
3.7.4 BLOW-DOWN SOLENOID VALVE
The blow-down solenoid valve opens to vent airflow from the sump tank to the atmosphere. The opening of
the valve is controlled by the adjustable set point of the microprocessor. Air from the blow-down solenoid
valve is vented back to the inlet air filter to reduce noise during blow-down. The blow-down solenoid valve
is located on the upper side of the sump tank.
3.7.5 LINE PRESSURE TRANSDUCER (P2)
The line pressure transducer (P2) controls the load/unload of the compressor. Opening or closing of the
blow-down solenoid valve based on the line pressure setting in the microprocessor. This set point for blow-
down control is usually set 10 psi over the desired setting of line pressure setting. The transducer also
allows for visual pressure reading during the operation of the compressor via the microprocessor. These
settings are initially determined by the factory, but can be adjusted accordingly within the limitations of the
compressor according to
6.11 Pressure Adjustment
.
3.8
MONITORING SYSTEM
The monitoring system utilizes the microprocessor to compile the needed data thru the use of sump pres-
sure transducer (P1), line pressure transducer (P2) and compressor unit discharge temperature sensor.
The components not only control system load/unload along with safety shut-downs but also allow for visual
display of the values as selected thru the microprocessor.