BENDIX SD-01-670 Manual Do Utilizador
3
FIGURE 4 - OPERATIONAL-LOADED (INTAKE)
AIR COMPRESSION (LOADED)
When the piston reaches approximately bottom dead
center (BDC) the inlet check valve and sliding inlet valve
close. Air above the piston is trapped by the closed inlet
valve and is compressed as the piston begins to move
toward top dead center (TDC). When air in the cylinder
bore reaches a pressure greater than that of the system
pressure the discharge valves open and air fl ows into the
discharge line and air brake system.
center (BDC) the inlet check valve and sliding inlet valve
close. Air above the piston is trapped by the closed inlet
valve and is compressed as the piston begins to move
toward top dead center (TDC). When air in the cylinder
bore reaches a pressure greater than that of the system
pressure the discharge valves open and air fl ows into the
discharge line and air brake system.
NON-COMPRESSION OF AIR (UNLOADED)
When air pressure in the supply reservoir reaches the
cut-out setting of the governor, the governor delivers
system air to the control port of the synchro valve. The
synchro valve opens in response to control pressure
from the governor and delivers system pressure to either
of the two compressor unloader ports. Air entering the
cut-out setting of the governor, the governor delivers
system air to the control port of the synchro valve. The
synchro valve opens in response to control pressure
from the governor and delivers system pressure to either
of the two compressor unloader ports. Air entering the
unloader port acts on one unloader plunger directly and is
simultaneously conducted through a passage in the valve
body assembly to the other unloader plunger.
simultaneously conducted through a passage in the valve
body assembly to the other unloader plunger.
The unloader plungers move horizontally in their bores
in response to control pressure from the governor and
synchro valve. A guide pin in the unloader plunger rotates
the pivot arm which causes the inlet valve to slide. As the
inlet valve slides from the loaded to the unloaded position
it blocks the two discharge ports and opens the six inlet
ports connecting the cylinder bore to the ESS chamber.
When the piston travels upward, air in the cylinder is
trapped between the top of the piston and the closed inlet
check valve and is compressed. The intake check valves
prevent the intake air from escaping through the air intake
port when the compressor is in the unloaded ESS mode.
See Figures 5 & 7.
in response to control pressure from the governor and
synchro valve. A guide pin in the unloader plunger rotates
the pivot arm which causes the inlet valve to slide. As the
inlet valve slides from the loaded to the unloaded position
it blocks the two discharge ports and opens the six inlet
ports connecting the cylinder bore to the ESS chamber.
When the piston travels upward, air in the cylinder is
trapped between the top of the piston and the closed inlet
check valve and is compressed. The intake check valves
prevent the intake air from escaping through the air intake
port when the compressor is in the unloaded ESS mode.
See Figures 5 & 7.
The added volume of the ESS chamber lowers the amount
of compression. Air that is compressed during the upward
movement of the piston provides a driving force for the
piston during its downward movement. As one piston is
moving downward the opposing piston is moving up. With
the exception of losses in the form of heat, which is formed
during compression, the energy used to compress the air
will be reused as the driving force for the downward stroke
of the piston. This results in the compressor using very
little power in its unloading position. See Figures 6 & 7.
of compression. Air that is compressed during the upward
movement of the piston provides a driving force for the
piston during its downward movement. As one piston is
moving downward the opposing piston is moving up. With
the exception of losses in the form of heat, which is formed
during compression, the energy used to compress the air
will be reused as the driving force for the downward stroke
of the piston. This results in the compressor using very
little power in its unloading position. See Figures 6 & 7.
DuraFlo
596
™
compressors can also be discharge line
unloaded which would eliminate the need for the synchro
valve, however, the power savings associated with the ESS
system would not be realized.
valve, however, the power savings associated with the ESS
system would not be realized.
PISTON
MOVING
DOWN
AIR
INLET
PORT
INLET
VALVE
OPEN
AIR
DISCHARGE
PORT
DISCHARGE
VALVE
CLOSED
UNLOADER
PISTON
INLET CHECK
VALVE OPEN
ESS
CHAMBER
FIGURE 5 - OPERATIONAL-LOADED (COMPRESSION)
PISTON
MOVING
UP
AIR
DISCHARGE
PORT
INLET
VALVE
CLOSED
AIR
INLET
PORT
DISCHARGE
VALVE
OPEN
UNLOADER
PISTON
INLET CHECK VALVE
CLOSED
ESS
CHAMBER
FIGURE 6 - OPERATIONAL-UNLOADED
PISTON MOVING
UP & DOWN
INLET CHECK VALVE
CLOSED
AIR
INLET
PORT
INLET
VALVE
OPEN
AIR
DISCHARGE
PORT
DISCHARGE
VALVE
CLOSED
UNLOADER PISTON
& PIVOT ARM SLIDES
INLET VALVE OVER
ESS
CHAMBER