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VR4V0 pages
CMYK
PILOT OPERATED PRESSURE RELIEF VALVE - Series VR4V
The Veljan Pressure Relief Valve series VR4V are pilot operated and work
Internal Drain
on the principle of hydraulic balancing. These valves are used to limit the
A
system pressure in a hydraulic system and protect the system against
pressure overload. Accurate pressure control even under wide flow
X
B
PC
Y
variations are achieved by these valves. The valves may also be used to
generate a pressure drop in a hydraulic circuit.
VR4V consist of a high flow poppet type seat valve section controlled by
External Drain
the low flow, adjustable pilot section mounted on top. Pressure setting is
A
achieved by means of knurled knob. For tamper proof setting, an acorn nut
with lead seal is available as option. Optional vent valve VVV01
B
sandwiched between pilot section and the main body can be used for
X
Y1
venting the VR4V valves.
Exceptionally fast response is obtained due to the precise ratio between
the main piston area and its mass. High pressure stability is an outstanding
feature of VR4V valves.
VR4V03 pilot valve
Y 1 (OPTIONAL)
Normally port A is connected to pump and port B to tank .
VR4V06/10 pilot valve
Y 1 (OPTIONAL)
At low pressure, flow entering port A is blocked by the
main poppet. Pressure at port A passes to the pilot section
as well as to the top of the main poppet through orifices.
No flow takes place in this portion until the pressure
overcomes the spring setting of the pilot cone. This pilot
cone is lifted from its seat releasing a small pilot flow to tank
X
and resulting in a pressure drop across the main poppet.
The main poppet opens and allows only enough flow from
port A to port B maintaining inlet pressure at the set value of
the pilot spring. At drop of inlet pressure below the set
value, the main poppet closes instantly.
Pilot drain is normally through port B for internal drain
valves. External drain from port Y or Y1 is optional. Port X
A
B
Y
may be used for venting or remote control of VR4V valves.
7
CMYK
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