Bendix Commercial Vehicle Systems RV-4 PRESSURE REDUCING VALVE 4/04 - Manual

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Bendix ® RV-4 ™ Pressure Reducing Valve
SD-03-3520
FIGURE 1
GENERAL DESCRIPTION
The RV-4 ™ pressure reducing valve is a normally open
pressure control device. The function of the RV-4 ™ 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-4 ™ valve has one supply port and two delivery ports.
A single pipe plug is installed in the control port and should
remain in place.
OPERATION
The spring force exerted on the balance 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
control piston is sealed by the exhaust valve. Compressed
air entering the supply port flows past the open inlet valve,
around the balance piston and out the two delivery ports.
When air pressure on the balance 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 under the balance piston overcomes air
pressure. Subsequent piston movement will unseat the inlet
valve allowing additional air pressure into the delivery lines.
If pressure in the delivery lines exceeds the pressure setting
of the valve, the force exerted by the air pressure will be
greater than the spring force. The balance 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 will remain closed.
MOUNTING
HOLE (2)
EXHAUST
CONTROL
PORT
(PLUGGED)
DELIVERY (2)
SUPPLY
PORT
BALANCE
PISTON
SPRINGS
DELIVERY
PORT (2)
SUPPLY
PORT
BALANCE
PISTON
CONTROL
PISTON
CONTROL
PORT
(PLUGGED)
EXHAUST
SPRING
SHIMS
EXHAUST PASSAGE
VALVE
SPRING