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
Specication 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 specications 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