Relief Valves
Description
Symbol
Cross Section
Cavity Details
156
VH043
METRIC Cartridge - 420 bar
Direct acting - Poppet type
Technical Features
RVDC.M20 Valve Series
1 2
All external surfaces are zinc plated and corro-
sion-proof. All valve parts are made of high strength
steel. Poppet is hardened and ground to guarantee
minimal wear and to extend service life. Adjust-
ment screw cannot be backed out of the valve. The
valve has a balancing design allowing consistent
relief operation and valve setting indipendent of
backpressure at tank (port 2). Optional spring ran-
ges to 420 bar (6000 psi). Metric cavity.
A screw-in, cartridge style, direct acting, poppet type, nor-
mally closed hydraulic relief valve. It’s typically used to
protect hydraulic components from pressure transients.
When the pressure at the Inlet (1) reaches the valve set-
ting, the valve starts to open to tank (2) throttling flow to
minimize the pressure rise. The innovative geometry of
the deflector provides in fact a very low rise rate, and the
poppet design guarantees great stability. The cartridge of-
fers quick response to load changes in hydraulic circuits
requiring low internal leakage as well as limited hysteresis.
Technical Data
157
Specication may change without notice.
Ordering Code
Maximum operating pressure 420 bar
Maximum flow 30 l/min
Setting Pressure See table below
Maximum internal leakage 1 cm
3
/min to 80% of nominal set point
External component treatment
Zn/Fe - standard (96h)
Zn/Ni (720h)
O-ring Temperature Range -30° C to 110° C (standard sealing NBR - BUNA-N)
Oil Temperature Range -30° C to 110° C
Pressure settings established @5 l/min
Reseat pressure nominal 85% of cracking pressure
Fluids Mineral - based or synthetics with lubricating properties
Viscosities 7,4 to 420 cSt
Filtration 20/18/15 ISO 4406 (maximum ltration admitted)
Orientation No restrictions
Installation torque 40-50 Nm (Hex. 22)
Tightening torque nut 20-25 Nm (Hex. 19)
Tightening torque blind nut 18-22 Nm (Hex. 17)
Technical specications for characterization See page 480
Declared reset value is obtained with valve set max P -10%
Oil testing condition ISO VG 46 cSt
Seal kit code SK.020
Weight 0,210 kg
Relief Valves
Springs’ Graphs
2
p/Q performance
p/Q performance
158
Flow (l/min)
Flow (l/min)
Pressure (bar)
Pressure (bar)
Spring = N (56 - 110bar)
Spring = Y (5 - 55bar)
1
RVDC.M20 Valve Series
Note: The performance chart illustrates flow handling capacity for each
spring bias options. P/Q curves are recorded at TOil = 40°C and 46 cSt
159
Specication may change without notice.
4
5
p/Q performance
Flow (l/min)
Pressure (bar)
3
Spring = G (216 - 350bar)
Spring = V (351 - 420bar)
Spring = B (111 - 215bar)
p/Q performance
p/Q performance
Flow (l/min)
Pressure (bar)
Pressure (bar)
Flow (l/min)