BENDIX SD-03-4510 Manual De Usuario

Descargar
Página de 6
2
valve fl ows out the service reservoir port and then opens 
the spring brake reservoir check valve, allowing air to fi ll 
the spring brake reservoir. As air is fi lling the spring brake 
reservoir, it also fl ows by the open control inlet and out 
the delivery ports of the SR-2
 valve into the spring brake 
emergency ports releasing the spring brakes.
PARK APPLICATION (Fig. 3)
To park the trailer, either the trailer supply valve or the 
parking control valve, which are located in the cab, are 
actuated and the trailer supply line is exhausted. When 
the trailer supply line is exhausted, air pressure is removed 
from the control and pressure protection pistons. With 
air pressure removed the control piston is moved by the 
return spring, control inlet valve closes and the exhaust 
passage through the control piston opens. Opening the 
exhaust allows air in the spring brake emergency section 
to be exhausted out the exhaust port of the SR-2
 valve. 
Spring force above the pressure protection piston closes 
the pressure protection valve while the service and spring 
brake reservoir check valves close and protect against the 
loss of pressure in either reservoir.
SERVICE APPLICATION WITH PARKING BRAKES
APPLIED OPTIONAL ANTI-COMPOUNDING PIPING
(Fig. 4)
With the optional anti-compounding feature of the SR-2
 
valve in use, the exhaust port of the SR-2
 valve receives 
normal service application pressure through a line 
connecting it to the delivery of the trailer service system. 
If a service brake application is made while the spring 
brakes are applied, compounding of both applications 
is prevented by service air pressure entering the SR-2
 
valve exhaust port, fl owing through the exhaust passage 
of the control piston, past the open exhaust valve and out 
the SR-2
 valve delivery port to the emergency section of 
the spring brakes.
NOTE:  During normal vehicle operation, with the spring 
brakes released, service air pressure will enter 
the SR-2
 valve as described, but will stop at the 
closed exhaust valve. See Figure 2.
SERVICE 
RESERVOIR 
CHECK VALVE
FIGURE 2 - SR-2
 TRAILER SPRING BRAKE VALVE 
CHARGING ABOVE 55 PSI
SPRING BRAKE 
RESERVOIR 
CHECK VALVE
SPRING 
BRAKE 
RESERVOIR
CONTROL INLET & 
EXHAUST VALVE
SPRING BRAKE
SERVICE 
RESERVOIR
TRAILER SUPPLY
LINE
TRAILER SERVICE
LINE
RELAY VALVE OR 
MODULATOR
PRESS. 
PROTECTION 
VALVE
PRESS. 
PROTECTION 
INLET VALVE
CONTROL 
PISTON
SERVICE 
RESERVOIR 
CHECK VALVE
FIGURE 3 - SR-2
 TRAILER SPRING BRAKE VALVE PARK 
APPLICATION
SPRING BRAKE 
RESERVOIR 
CHECK VALVE
SPRING 
BRAKE 
RESERVOIR
CONTROL INLET & 
EXHAUST VALVE
SPRING BRAKE
SERVICE 
RESERVOIR
TRAILER SUPPLY
LINE
TRAILER SERVICE
LINE
RELAY VALVE OR 
MODULATOR
PRESS. 
PROTECTION 
VALVE
PRESS. 
PROTECTION 
INLET VALVE
CONTROL 
PISTON
SERVICE 
RESERVOIR 
CHECK VALVE
FIGURE 4 - SR-2
 TRAILER SPRING BRAKE VALVE
OPTIONAL ANTI-COMPOUNDING
SPRING BRAKE 
RESERVOIR 
CHECK VALVE
SPRING 
BRAKE 
RESERVOIR
CONTROL INLET & 
EXHAUST VALVE
SPRING BRAKE
RELAY VALVE OR 
MODULATOR
PRESS. 
PROTECTION 
VALVE
PRESS. 
PROTECTION 
INLET VALVE
CONTROL 
PISTON
SERVICE 
RESERVOIR
TRAILER SUPPLY
LINE
TRAILER SERVICE
LINE