User's Manual
5
FIGURE 8A - SYSTEM DRAWING
AIR DRYER
RESERVOIR DRAIN
SERVICE RESERVOIR
(SUPPLY RESERVOIR)
COMPRESSOR
GOVERNOR
(GOVERNOR PLUS SYNCHRO VALVE
FOR THE BENDIX
®
DURAFLO
596
™
COMPRESSOR)
DISCHARGE LINE
OPTIONAL “PING” TANK
OPTIONAL BENDIX
®
PURAGUARD
®
QC
™
OIL COALESCING FILTER
The Air Brake Charging System supplies the
compressed air for the braking system, as well as other air
accessories for the vehicle. The system usually consists
of an air compressor, governor, discharge line, air dryer,
and service reservoir.
FIGURE 8B - DISCHARGE LINE SAFETY VALVE
HOLE
THREAD
DISCHARGE LINE TEMPERATURE
When the temperature of the compressed air that enters
the air dryer is within the normal range, the air dryer can
remove most of the charging system oil. If the temperature
of the compressed air is above the normal range, oil as
oil-vapor is able to pass through the air dryer and into the
air system. Larger diameter discharge lines and/or longer
discharge line lengths can help reduce the temperature.
The air dryer contains a fi lter that collects oil droplets, and
a desiccant bed that removes almost all of the remaining
water vapor. The compressed air is then passed to the air
brake service (supply) reservoir. The oil droplets and the
water collected are automatically purged when the governor
reaches its "cut-out" setting.
For vehicles with accessories that are sensitive to small
amounts of oil, we recommend installation of a Bendix
®
PuraGuard
®
QC oil coalescing fi lter, designed to minimize
the amount of oil present.
LUBRICATION
The vehicle's engine provides a continuous supply of oil
to the compressor. Oil is routed from the engine to the
compressor oil inlet. An oil passage in the crankshaft
conducts pressurized oil to precision sleeve main bearings
and to the connecting rod bearings. Spray lubrication of
the cylinder bores, connecting rod wrist pin bushings, and
ball type main bearings is obtained as oil is forced out
around the crankshaft journals by engine oil pressure.
Oil then falls to the bottom of the compressor crankcase
and is returned to the engine through drain holes in the
compressor mounting fl ange.
COOLING
Air fl owing through the engine compartment from the action
of the engine fan and the movement of the vehicle assists
in cooling the compressor. Cooling fi ns are part of the
crankcase/cylinder block casting. Coolant fl owing from the
engine cooling system through connecting lines enters the
head and passes through internal passages in the cylinder
head and is returned to the engine. Proper cooling is
important in maintaining discharge air temperatures below
the maximum recommended 400 degrees Fahrenheit.
Figure 9 illustrates the various approved coolant fl ow
connections. See the tabulated technical data in the back
of this manual for specifi c requirements.
AIR INDUCTION
The DuraFlo
596
™
compressor is approved for natural
aspiration only. The compressor inlet is connected to the
vacuum side of the engine air induction system. See the
tabulated technical data in the back of this manual for
specifi c requirements.