FLUID POWER
61
iVT International Off-Highway 2020
place them in the machine exactly where
they are required.
The block construction provides the designer
with a lot of flexibility in selecting suitable valve
size per function. With this, on the one hand a
technical solution precisely adapted to the
requirements is achieved. On the other it’s possible
to optimize the space requirements and costs.
Efficient and space-saving
The new spool valve cartridges correspond to the
requirements to design the systems as efficient
and economical. In addition, part of the valve
range of the sizes M33 and M42 are pilot operated
pressure relief valves and pressure control valves
with manual as well as proportional adjustment,
manual and proportional throttles as well as
pressure-compensated flow control valves in
2-way and 3-way versions, with manual as well as
proportional adjustment.
For applications, where a load has to be
securely held, pilot operated, leakage-free poppet
valves are available. For demanding load holding
and lowering functions, tight-seating,
proportionally adjustable and load–compensated
flow control valves have proved successful. The
large selection of screw-in valves is designed for
operating pressures up to 420 bar. Corresponding
to the size of these valves and depending on the
valve type, volume flows of up to 400 l/min can be
controlled. A very good controllability of the
screw-in valves in the fine range is the prerequisite
for operating the system of the customer with
high precision and the demanded efficiency.
The type screw-in spool valve does not
concern an independent element, it has to be
externally pilot operated with a hydraulic
pressure. Therefore additionally driving elements
or pilot operation valves are required. For the
4/3-way function (4 connections, 3 switching
positions) no bores are foreseen in the ISO cavity
system. For this reason, Wandfluh has elaborated
a proprietary cavity type. The size of the valve
cartridge is determined by the size of the volume
flow and the required lateral bores for the inlet
and outlet tubes.
The pilot-operated valve can be arranged
directly at the spool valve cartridge, but does not
have to be. The pilot control can be located
anywhere and connected to the control block
with small control lines.
BELOW: Pressure
reducing cartridge
M42 Qmax 250 l/min,
pmax 400 bar
ABOVE: Proportional
directional valve
cartridge M42 Qmax 250
l/min, pmax 315 bar