BENDIX SD-08-2412 Manuale Utente

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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

CHECK
VALVE
FIGURE 2 - BENDIX
® 
AD-9
®
 AND AD-9
®
 IPC AIR DRYER CHARGE CYCLE
CHECK
VALVE
ASSEMBLY