Bendix Commercial Vehicle Systems AD-SP SYSTEM PURGE AIR DRYER 10/04 - Manual (Page 3)

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FIGURE 4 - AD-SP ™ AIR DRYER RELIEF VALVE OPERATION
DESICCANT
OIL
SEPARATOR
DELIVERY
CHECK
DELIVERY
PORT
TURBO
CUTOFF
CONTROL
PORT
GOVERNOR
COMPRESSOR
PURGE /
RELIEF
VALVE
FRONT
RESERVOIR SC-PR ™
VALVE
REAR
RESERVOIR
ENGINE
TURBO
PURGE
PISTON
EXHAUST
PORT
SUPPLY
PORT
PURGE
ORIFICE
FIGURE 3 - AD-SP ™ AIR DRYER CHARGE CYCLE
DESICCANT
OIL
SEPARATOR
DELIVERY
CHECK
DELIVERY
PORT
TURBO
CUTOFF
CONTROL
PORT
MALFUNCTIONING
GOVERNOR
COMPRESSOR
PURGE /
RELIEF
VALVE
FRONT
RESERVOIR
SC-PR ™
VALVE
REAR
RESERVOIR
ENGINE
TURBO EXHAUST
PORT
SUPPLY
PORT
PURGE
ORIFICE
The air dryer will remain in the charge cycle until the air
brake system pressure builds to the governor cutout setting.
To protect against over pressurization of the AD-SP
™ air
dryer, the purge valve incorporates an integral relief valve
feature. In the event that the compressor unloader
mechanism or governor malfunctions, at approximately 200
psi supply air pressure the AD-SP
™ air dryer purge valve
will open (without control pressure), and vent excess air
pressure to atmosphere (refer to Figure 4).
PURGE
PISTON