Air Dryer/Reservoir System Purge Cycle; Charge Cycle - BENDIX AD-IS AIR DRYER Manual

DELIVERY
CHECK
VALVE
(CLOSED)
GOVERNOR
UNLOADER
PORT
PURGE
INLET
CONTROL
PORT
CHANNEL
(IN)
TURBO CUT-
OFF VALVE
(CLOSED)
COMPRESSOR
GOVERNOR SIGNALS AIR
COMPRESSOR TO SUSPEND
COMPRESSED AIR SUPPLY
TO AD-IS ® AIR DRYER
®
FIGURE 3 - AD-IS AIR DRYER AND RESERVOIR SYSTEM PURGE CYCLE
®
AD-IS AIR DRYER AND RESERVOIR SYSTEM
OPERATION: GENERAL
®
The AD-IS air dryer and reservoir system is designed to
receive compressed air from the vehicle air compressor,
clean and dry the air, deliver air to the vehicle's primary
reservoir, secondary reservoir and accessories, and control
the compressor/dryer charge cycle.
AIR DRYER AND RESERVOIR SYSTEM
OPERATION: GENERAL
The AD-IS ® air dryerand reservoir system alternates between
two operational modes or "cycles" during operation: the
EXHAUST
PURGE
VALVE
SAFETY
(OPEN)
VALVE
PRIMARY
SECONDARY
ENGINE
TURBO
(Refer to Figure 2)
DESICCANT
BED
OIL
SEPARATOR
PRESSURE PROTECTION
VALVES
A
B C
AUXILIARY PORTS
PORT
(TO ACCESSORIES)
(PRI)
PORT
(SEC)
DIAGRAM SHOWS ALL PRESSURE PROTECTION VALVES
OPEN.
Charge Cycle and the Purge Cycle. The following
descriptions are separated into these "cycles" of operation.

CHARGE CYCLE

When the compressor is loaded (compressing air)
compressed air flows through the compressor discharge
line to the inlet (1/IN) port of the air dryer body. The
compressed air often includes contaminates such as oil,
oil vapor, water and water vapor.
Traveling through the discharge line and into the air dryer,
the temperature of the compressed air falls, causing some
PURGE
ORIFICE
PURGE
RESERVOIR
D
PURGE
RESERVOIR
DRAIN VALVE
SECONDARY
RESERVOIR
PRIMARY
RESERVOIR
(Refer to Figure 2)
3