VAG Operation and Maintenance Instructions • 6
Picture 5: Limit curve of the VAG EKN
®
Butterfly Valve
Example of a limit curve of the VAG EKN
®
Butterfly Valve
At a pressure of 5 bars and a flow velocity of 8 m/s, the hy-
draulic moment of the flow around the disk is so high that a
PN 16 VAG EKN
®
Butterfly Valve must be selected.
3.4 Permissible and impermissible modes of
operation
The maximum operating temperatures and operating
pressures specified in the technical documentation
(KAT-A 1310) must not be exceeded. The pressure
applied to the closed valve must not exceed its rated
pressure.
The VAG EKN
®
Butterfly Valve has its limit stop in the gearbox.
This stop limits both the open and the closed position. Due to the
automatic lock of the gear, it suffices to touch the end position.
Do not tighten it as this will not improve the tightness of the valve.
Permanent operation of the valve in throttle position can result
in its increased wear and tear and even destroy the valve or the
downstram pipeline. The operational limits according to Section
3.3.1 need to be established.
3.5 Special type with UVV safety interlock
For safety reasons, it is frequently necessary to install lockable
butterfly valves, i.e. the accidental opening of the valve or the
breaking of a shaft through the disk closing is prevented by lo-
cking the disk with an additional lock. Locking is carried out with
three bolts located on the circumference and at least one bolt
is movable. This locking system may also be double-sided, in
which case three more bolts are placed on the circumference.
In this case, we distinguish between fixed stops and movable
bolts in the body. Please refer to the illustration of the respective
model below for the secured side of the pipeline which is opened
for inspection and maintenance purposes while the operational
pressure of the medium is maintained on the opposite side of
the disk.
Picture 6: VAG EKN
®
Butterfly Valve with UVV safety interlock
