BENDIX SD-08-2418 Manual page 3

DESCRIPTION
The function of both the Bendix
Air Dryer) air dryer & reservoir system, and the Bendix
AD-IS PuraGuard oil coalescing air dryer & reservoir
® ®
system, is to collect and remove air system contaminants
in solid, liquid, and aerosol form before they enter the brake
system. As a module, they provide heavy vehicles with an
integrated vehicle air dryer, purge reservoir, governor, and
a number of the charging valve components in a complete
assembly. These components have been designed as an
integrated air supply system.
Both air dryer & reservoir systems provide clean, dry air
to the components of the brake system – which increases
the life of the system and reduces maintenance costs.
The need for daily manual draining of the reservoirs is
eliminated.
The Bendix AD-IS PuraGuard oil coalescing air dryer has
an identical appearance to the standard Bendix AD-IS air
dryer with one exception – it contains a coalescing media at
the inlet of the desiccant bed and an identifying medallion
on the top (See Figure 1). The coalescing media provides
a higher level of oil removal over the standard AD-IS air
dryer. The AD-IS PuraGuard oil coalescing air dryer has
all of the same functions as the standard AD-IS air dryer
and is used in applications where lower oil concentration
levels are required.
IMPORTANT
When servicing, note that standard AD-IS air dryers or
air dryer cartridges may be serviced with PuraGuard oil
coalescing air dryers or cartridges, however, PuraGuard oil
coalescing air dryers or cartridges must only be serviced
with like replacements.
Note: Unless otherwise stated in this manual, AD-IS air
dryer & reservoir systems refers to both the standard and
the PuraGuard oil coalescing air dryer & reservoir systems.
The function of the pressure protection valves is to protect
each reservoir from a pressure loss in the other reservoir or
a pressure loss in an air accessory. Each of the pressure
protection valves in the AD-IS air dryer & reservoir systems
may have different pressure settings. These are factory set
and must not be changed or adjusted.
The air dryer & reservoir system consists of a spin on
desiccant cartridge secured to a base assembly. The
base assembly contains a delivery check valve assembly,
safety valve, heater and thermostat assembly, pressure
protection valves, threaded air connections, and the purge
valve assembly.
AD-IS (Integrated Solution
® ®
Air Connection
Port ID
® 1
Inlet Port (air in)
IN
21 Delivery Port Out (to Primary
PRI Reservoir)
Delivery Port Out (to Secondary
22
SEC
Reservoir)
24
Auxiliary Delivery Port (air out)
AUX 1
23
Auxiliary Delivery Port (air out)
AUX 2
Unloader Control Air
UNL
(Bendix
Common Reservoir Pressure
RES
(D-2A Governor)
EXH Governor Exhaust
Table 1 – Port Designations
The removable purge valve assembly incorporates the
purge valve mechanism and a turbocharger cut-off feature
that is designed to prevent loss of engine turbo boost
pressure during the purge cycle of the Bendix AD-IS air
dryer & reservoir system. For ease of maintenance, all
replaceable assemblies can be serviced without removal
of the air dryer & reservoir system from its mounting on
the vehicle. Refer to the Preventive Maintenance section.
BENDIX AD-IS AIR DRYER & RESERVOIR
SYSTEM OPERATION: GENERAL
(Refer to Figure 2.)
The Bendix AD-IS air dryer & reservoir systems are
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.
The AD-IS air dryer & reservoir system alternates between
two modes, or cycles, during operation: the Charge Cycle
and the Purge Cycle. What follows describes these cycles
of operation.
Function/
Connection
D-2A Governor)
® ™
Qty.
1
1
1
4
1
2
2
1
3