Service Application - BENDIX SR-1 SPRING BRAKE VALVE Manual

DOUBLE
CHECK
VALVE
FIGURE 7 - SERVICE APPLICATION - LOSS OF #2 RESERVOIR
DOUBLE
CHECK
VALVE
FIGURE 8 - SERVICE APPLICATION - LOSS OF #1 RESERVOIR
brake valve will apply the service section of the spring brake
actuators.
OPERATION - SERVICE APPLICATION WITH
LOSS OF NO. 1 RESERVOIR PRESSURE
If air pressure in the No. 1 service reservoir falls below
approximately 55 P.S.I., the pressure beneath piston A is
insufficient to resist the spring force above and piston A
moves into contact with valve A. Initial contact between piston
A and valve A closes the hollow exhaust passage of piston
A. Continued movement of the piston opens the inlet of
valve A.
The No. 2 service reservoir and the park control valve are
protected from pressure loss by the action of the double
check valve.
4
#2 SERVICE
RESERVOIR
#1 SERVICE
RESERVOIR
INLET &
EXHAUST A
PARK
CONTROL
#2 SERVICE
RESERVOIR
#1 SERVICE
RESERVOIR
EXHAUST A
PARK
CONTROL
PISTON A
INLET &
EXHAUST
B
EXHAUST
SB-3
PISTON A
INLET &
INLET &
EXHAUST
B
EXHAUST
SB-3
When a service application of the dual brake valve is made,
air delivered from the No. 2 delivery circuit of the dual
brake valve enters the SR-1
the control port moves past the inlet of valve A and is
conducted through a passage in the body to the underside
of piston B. The air pressure moves piston B up, opening
the exhaust of valve B. When the exhaust of valve B opens,
air pressure trapped in the emergency section of the spring
brake actuator is allowed to escape, resulting in an
emergency brake application. The air pressure released from
the spring brake is proportional to the air pressure delivered
to the control port of the SR-1
the dual brake valve.
PISTON B
CHECK VALVE
PISTON B
CHECK VALVE
™
valve control port. Air entering
™ valve by the No. 2 delivery of