Bendix Commercial Vehicle Systems DRM DRYER RESERVOIR MODULE 3/07 - Manual (Page 2)

2
FIGURE 2 - AD-IS ® AIR DRYER CHARGE CYCLE. DIAGRAM SHOWS PRESSURE PROTECTION VALVES A AND B OPEN, C & D CLOSED.
COMPRESSOR
GOVERNOR
PURGE
CONTROL
CHANNEL
DESICCANT
BED
DELIVERY
CHECK
VALVE
(OPEN)
PURGE
RESERVOIR
PRIMARY
PORT
(PRI)
PURGE
VALVE
(CLOSED)
TURBO
CUTOFF
VALVE
(OPEN)
ENGINE
TURBO
UNLOADER
PORT
INLET
PORT
(IN)
OIL
SEPARATOR
PURGE
ORIFICE
PRIMARY
RESERVOIR
SECONDARY
RESERVOIR
PRESSURE PROTECTION
VALVES
AUXILIARY PORTS
(TO ACCESSORIES)
SEE
NOTE 1
Note 1:
The AD-IS ® air dryer purge piston has a
purge control channel drain. This allows
any condensation in this area to flow
past a diaphragm in the top of the purge
piston and out through a channel in the
middle of the central bolt of the purge
assembly to be drained. During the
purge cycle this drain is closed.
SAFETY
VALVE
PURGE
RESERVOIR
DRAIN VALVE
The removable purge valve assembly incorporates the purge
valve mechanism and a turbocharger cutoff feature that is
designed to prevent loss of engine “turbo” boost pressure
during the purge cycle of the AD-IS
® air dryer. For ease of
serviceability, all replaceable assemblies can be replaced
without removal of the air dryer from its mounting on the
vehicle. Refer to Preventive Maintenance section.
DRM ™ DRYER MODULE OPERATION:
GENERAL (Refer to Figure 2)
The DRM ™ dryer module is designed to receive compressed
air from the vehicle air compressor, clean and dry the air
using the AD-IS
® air dryer, deliver air to the vehicle’s primary
reservoir, secondary reservoir and accessories, and control
the compressor/dryer charge cycle.
AIR DRYER OPERATION: GENERAL
The AD-IS ® air dryer alternates between two operational
modes or “cycles” during operation: the Charge Cycle and
the Purge Cycle. The following descriptions are separated
into these “cycles” of operation.
CHARGE CYCLE (Refer to Figure 2)
When the compressor is loaded (compressing air)
compressed air, along with oil, oil vapor, water and water
A
D
C B