Bendix Commercial Vehicle Systems PRESSURE PROTECTION VALVES - Manual

1
SD-03-2010
Bendix ® PR-2 ™ , PR-3 ™ & PR-4 ™ Pressure Protection Valves
DESCRIPTION
The pressure protection valve is a normally closed,
pressure control valve which can be referred to as a
non-exhausting sequence valve. These valves are used in
many different applications. An example would be in an air
brake system to protect one reservoir, or reservoir system
from another, by closing automatically at a preset pressure
should a reservoir system failure occur. The valves can also
be used to delay fi lling of auxiliary reservoirs to ensure a
quick build-up of brake system pressure.
The Bendix ® PR-2 ™ and PR-4 ™ pressure protection valves
have one 1/4” N.P.T.F. supply port and one 1/4” N.P.T.F.
delivery port which are identifi ed. Both valves are provided
with two 9/32” mounting holes through the body. The closing
pressure of the PR-2
™ valve is externally adjustable while
the PR-4 ™ valve has a fi xed setting.
DELIVERY
PORT
SUPPLY
PORT
PISTON
SPRING
INLET
VALVE
CAP
BENDIX ® PR-4 ™ PRESSURE PROTECTION VALVE BENDIX ® PR-3 ™ PRESSURE PROTECTION VALVE
PR-3 ™ OR PR-4 ™
PRESSURE PROTECTION
VALVES
INLET
VALVE SPRING
INLET
VALVE
PISTON PLUG
O-RING
PRESSURE
REGULATING
SPRING
VALVE STEM
PISTON PLUG
BENDIX ® PR-2 ™ PRESSURE PROTECTION VALVE
EXHAUST
VENT
PISTON
O-RING
PISTON
SPRING
RETAINER
INLET
VALVE
PISTON
SPRING
CHECK
VALVE
CAP
SUPPLY
PORT
DELIVERY
PORT
SUPPLY
PORT
DELIVERY
PORT
PR-2 ™ PRESSURE
PROTECTION VALVE