Bendix Commercial Vehicle Systems AD-9 AND AD-9 IPC AIR DRYERS 4/11 - Manual (Page 2)

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of engine “turbo” boost pressure during the purge cycle of
the Bendix
® AD-9 ® and AD-9 ® IPC air dryers. For ease of
serviceability, the desiccant cartridge and discharge check
valve assembly are screw-in type. The purge valve housing
assembly – which includes the heater and thermostat
assembly – and the discharge check valve assembly are
serviceable from the exterior of the air dryer, while servicing
the screw-in desiccant cartridge requires removal of the air
dryer assembly from the vehicle.
The AD-9 IPC air dryer appears identical to the standard
AD-9 air dryer, but contains a coalescing media at
the inlet of the desiccant bed. This coalescing media
provides a higher level of oil removal over the standard
AD-9
air dryer. The AD-9 IPC air dryer has all the same
functions of the standard AD-9 air dryer, and is used
where oil is contaminating downstream components.
The Bendix AD-9 IPC air dryer can be identifi ed by the
IPC label (shown in Figure 1), located on the air dryer
housing.
The Bendix AD-9 and AD-9 IPC air dryers have three
female pipe thread air connections and each is identifi ed
as follows:
Port l.D. Function/Connection
CON 4................Control Port
(purge valve control and turbo cut-off)
SUP 11 .............Supply Port (air in)
DEL 2 ...............Delivery Port (air out)
OPERATION OF THE BENDIX AD-9 AIR
DRYER
The AD-9 and AD-9 IPC air dryers alternate between two
operational modes, or “cycles”, during operation: the charge
cycle and the purge cycle. The following description of
operation is 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
vapor – fl ows through the compressor discharge line to
the supply port of the air dryer end cover. As air travels
through the end cover assembly, its direction of flow
ORIFICE
PURGE
VOLUME
DELIVERY
PORT
HEATER
ELEMENT
SUMP
EXHAUST
PURGE
VALVE
RESERVOIR
SUPPLY
PORT
COMPRESSOR
GOVERNOR
ENGINE
TURBO
CONTROL
PORT
OIL
SEPARATOR
DESICCANT
BED
DESICCANT
CARTRIDGE
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CHECK
VALVE
FIGURE 2 - BENDIX ® AD-9 ® AND AD-9 ® IPC AIR DRYER CHARGE CYCLE
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CHECK
VALVE
ASSEMBLY
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