Page 4 - Energy_en

CONTROLLING ACTUATORS

Large process valves are often equipped with hydraulic actuations, since the high power
density of the hydraulics enables a compact solution. Depending on the field of applica-
tion, different requirements are placed on the hydraulic valves. This ranges from standard
valves to valves with low leakage, explosion protected executions through to corrosion and
acid-resistant components.

FUNCTION
On large process valves, a hydraulic actuator is mounted
which is generally a hydraulic cylinder. By means of Wand-
fluh valves, a precise and secure controlling of the hydraulic
cylinder is ensured. Since often only very small oil volumes
are employed, compact and low-leakage control valves are
of great importance. For the different actuators, a wide prod-
uct range of spool valves and poppet valves is available.

V

On
O

CONTROL
The actuators are mainly operated with on/off spool valves
that have reduced leakage. Since in an installation many
valves are controlled by means of a unit in the accumulator
unloading operation, the leakage accumulates. For this rea-
son, the smallest leakages possible are very important, but
without impairing the switching reliability in harsh environ-
ments. In oil and gas environments, the valves are equipped
with explosion protected solenoids. This execution is often
related with high demands concerning corrosion. It is cov-
ered with a zinc/nickel coating or with stainless materials
(AISI316L).

SPECIALITIES
• Low leakage spool valves, <15 ccm/min at 150 bar
• Tight, compact poppet valves with direct cable outlet
• Ex d spool valves, Ex ia spool valves with reduced leakage
• Manual overrides in various executions, also stainless

PAGE 2 | WANDFLUH ENERGY | APPLICATION | ACTUATORS