BENDIX SD-01-333 Manual De Usuario

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brake charging system performance which may require 
additional maintenance. Factors that add to the duty cycle 
are: air suspension, additional air accessories, use of an 
undersized compressor, frequent stops, excessive leakage 
from fi ttings, connections, lines, chambers or valves, etc. 
Refer to Table A in the Troubleshooting section for a guide 
to various duty cycles and the consideration that must be 
given to maintenance of other components.
COMPRESSOR INSTALLATION
While the original compressor installation is usually 
completed by the vehicle manufacturer, conditions of 
operation and maintenance may require additional 
consideration. The following presents base guidelines.
DISCHARGE LINE
The discharge line allows the air, water-vapor and oil-vapor 
mixture to cool between the compressor and air dryer or 
reservoir. The typical size of a vehicle's discharge line, 
(see column 2 of Table A in the Troubleshooting section) 
assumes a compressor with a normal (less than 25%) duty 
cycle, operating in a temperate climate. See Bendix and/or 
other air dryer manufacturer guidelines as needed.
The discharge line must maintain a constant slope down 
from the compressor to the air dryer inlet fi tting or reservoir 
to avoid low points where ice may form and block the fl ow. 
If, instead, ice blockages occur at the air dryer or reservoir 
inlet, insulation may be added here, or if the inlet fi tting is 
a typical 90 degree fi tting, it may be changed to a straight 
or 45 degree fi tting. Shorter discharge line lengths or 
insulation may be required in cold climates.
While not all compressors and charging systems are 
equipped with a discharge line safety valve this component 
is recommended. The discharge line safety valve is 
FIGURE 6A - SYSTEM DRAWING
FIGURE 6B - DISCHARGE LINE SAFETY VALVE
HOLE
THREAD
installed in the cylinder head (Tu-Flo
®
 550/750) or close to 
the compressor discharge port and protects against over 
pressurizing the compressor in the event of a discharge 
line freezeup.
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.
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.