Bendix Commercial Vehicle Systems RV-3 PRESSURE REDUCING VALVE 3/04 - Manual

1
®
SD-03-3515
GENERAL DESCRIPTION
The RV-3 ™ pressure reducing valve is a normally open
pressure control device. The function of the RV-3 ™ valve is
to reduce system air pressure and maintain a constant
specified pre-set pressure below that of system pressure.
Various pressure settings can be obtained through the use
of springs and shims in combination.
The RV-3 ™ valve has one supply port and one delivery port.
A single pipe plug is installed in the control port and should
remain in place for most applications of the RV-3
™ valve. A
rubber exhaust diaphragm is installed in the end of the valve
opposite the supply port. Two .28" (7.1mm) mounting holes
are cast into the valve body.
OPERATION
The spring force exerted on the piston determines the delivery
pressure of the valve. With no air pressure present at the
supply port, the inlet valve is unseated and open while the
exhaust passage through the center of the piston is sealed
by the exhaust valve. Compressed air entering the supply
port flows out the delivery port. Air simultaneously flows
between the piston stem and valve body to the underside of
the piston. When air pressure on the piston overcomes
spring force, the piston moves and the valve spring forces
the inlet valve on its seat, closing off the supply of air. The
exhaust remains closed. If air pressure in the delivery line
drops, spring force on the piston overcomes air pressure.
Subsequent piston movement will unseat the inlet valve
allowing additional air pressure into the delivery line. If
pressure in the delivery line exceeds the pressure setting of
the valve, the force exerted by the air pressure will be greater
than the spring force. The piston will move away from the
exhaust valve, permitting air to flow past the exhaust valve,
through the hollow piston stem and out the exhaust port.
The inlet valve remains seated.
FIGURE 1
Bendix ® RV-3 ™ Pressure Reducing Valve
RETAINER
PISTON
SUPPLY CAP
NUT O-RING
PLUGGED
PORT
MOUNTING
HOLES
SUPPLY
PORT
DELIVERY
PORT
EXHAUST
DIAPHRAGM
EXHAUST NUT
OUTER AND/OR
INNER SPRING
SHIMS
PISTON O-RING
VALVE BODY
INLET/EXHAUST
VALVE
SUPPLY
CAP NUT
VALVE STOP
INLET VALVE SPRING