PRODUCTS & SERVICES
WANDFLUH
COMPACT LOGIC ELEMENTS FOR HIGH FLOW RATES WITH LOW PRESSURE LOSS
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iVTInternational.com June 2020 43
Don’t drop the pressure
From a certain size on, hydraulic systems
require large volume flows with high
pressures. Such efficient systems can be found in
aluminium processing in the form of casting
presses with holding pressure systems, in the
opening mechanisms of large ship hatches, in
large freight elevators, in cranes or in the braking
systems of cable cars, not to mention the booms of
concrete pumps. To be able to carry out all these
large and heavy tasks at an efficient speed,
correspondingly powerful valve technology that
can be controlled precisely and sensitively despite
the large capacities is required. Wandfluh has
developed the 2-way slip-in cartridge valves for
such tasks and has continuously improved their
performance over the years.
The 2-way slip-in cartridge valves are inserted
in the control block into a bore standardised
according to ISO 7368 and closed with a control
cover. In operation, they merely act as amplifiers,
following the pilot valve on the cover that can be
controlled manually or electrically via an analogue
or digital interface. Combined with intelligent
electronics, complex hydraulic circuits that are
characterised by very high pressures and flows can
thus be implemented within a hydraulic block.
The proven range of 2-way slip-in cartridge
valves has been supplemented with significantly
more powerful valves in the nominal sizes NG16,
NG25, NG32, NG40 and NG50. The new series
is characterised by a three-part construction
and, thanks to optimised flow geometry, offers
practically a doubling of the maximum possible
flow rate, while still maintaining a very low
pressure drop Delta P. The slip-in cartridge valves
have also been given a higher pressure resistance
and are now approved for operation up to a
system pressure of 630 bar (9,000psi).
Due to these two aspects, it is now possible to
plan much smaller hydraulic systems. This means
that, compared to conventional valves, the next
smaller valve can be used without compromising
performance. This in turn leads to even lighter,
more compact and more efficient
hydraulic systems.
The new 2-way slip-in cartridge valves are
available in the two basic executions switching
and pressure function, and can be supplemented
by spools with non-return function, damping nose
and/or seal. The modular design of the individual
valve parts and the use of suitable cover and pilot
valve combinations allow a wide range of different
functions.
These include
spool valves
with start, stop
and directional
control, pressure
reducing valves
for pressure
limitation,
pressure relief,
pressure
sequence and
discharge
function or nonreturn
valves (spool valves with non-
return function).
With the new series from Wandluh, hydraulic
logic modules with a system pressure of 630 bar
and up to a maximum flow rate of 2,360 l/min
(with a pressure drop of 5 bar) can be combined in
one block to form a complex circuit while saving
space and weight. Thanks to the low pressure drop,
this type of circuit is very efficient and, compared
to a conventional hydraulic solution, has few
interfaces where leakage would be possible at all.
Fast set-up and precise control are the basic
requirements for a concrete pump boom to
withstand the demands on a construction site.
At the same time, the seat-tight valves prevent
the boom from sinking over time and causing
accidents. iVT
Author: Bruno Maier, valve development,
Wandfluh AG
C_xx (350 bar) C_ENxx (630 bar)
NG16 180 l/min 270 l/min
NG25 335 l/min 600 l/min
NG32 675 l/min 980 l/min
NG40 1,160 l/min 1,620 l/min
NG50 n/a 2,360 l/min
Volume flow data at Delta p of 5 bar
RIGHT: Cutaway model hydraulic block with
slip-in cartridge valve
Wandfluh’s C_ENxx
two-way slip-in
cartridge valves
Concrete pump boom
/pivt
/iVTInternational.com