6.1 General
Actuators (gears, pneumatic, hydraulic and electric actuators) are
designed for flow velocities according to Table 2 in EN 1074-1
(valves used for water supply; requirements relating to fitness for
use). Any deviating operating conditions need to be specified.
The adjustment of the limit stops (OPEN, CLOSE) must not be
changed without the manufacturer’s consent. If valves are ins-
talled without gear units it must be ensured that the valve is not
pressurised.
For detailed information on gears and actuators, please refer to
the operation manuals issued by the manufacturers of these com-
ponents (e.g. AUMA, Rotork).
The VAG EKN
®
Butterfly Valve has an adjustment angle of 90°.
The valve itself is not equipped with position limiters.
The actuator must be equipped with limit stops. The actuator
must be designed so that it turns counter-clockwise in relation to
the valve shaft!
The limit position adjustment is to be done in compliance with
the operating manuals issued by the respective gear manufactu-
rers, such as AUMA, Rotork etc. In case a gear is retrofitted, its
nominal torque and the adjustment of the limit stops “OPEN” and
“CLOSE” must be adapted to the valve.
Non-compliance with these regulations may endanger life and
limb and/or cause damage to the pipeline system. If actuators
powered by external sources of energy (electric, pneumatic or hy-
draulic) have to be disassembled from the valve, the safety inst-
ructions under Section 1.1 needs to be observed and the external
source of energy must be switched off and isolated.
Special care needs to be taken in case of hot surfaces. Touching
hot surfaces may result in burns. Even when the de-
vice is switched off, residual heat may cause burns.
Prior to any work make sure that the surface has
cooled down to room temperature.
6.2 Operating torques
Operating torques are the maximum required torques [in Nm] ac-
ting on the actuator stem at full differential pressure including a
safety factor of 1.5. If required, you can contact us for information
about the respective torques and/or controlling torques for elec-
tric actuators.
6.3
Emergency manual operation
(handwheel)
If the valve is operated via the handwheel of the elec-
tric multiturn actuator, the torque switches do not
have any safety function.
Operation via the emergency handwheel is intended
for short periods only, for commissioning and for ex-
ceptional situations.
The emergency handwheel is not suitable for conti-
nuous operation.
If, in intermediate position, a foreign body gets jammed in the
valve, this may result in higher operating forces – especially with
heavily geared down actuators – which in turn may damage the
actuation components. Therefore:
If you meet any resistance while operating the valve with the emer-
gency handwheel, turn the handwheel in the opposite direction for
some turns and then turn it in the direction again in which the
disturbance was found (washing out of the foreign body). Conti-
nue operation very carefully, never use excessive force and repeat
washing, if necessary.
Picture 14: Gearbox markings
VAG Operation and Maintenance Instructions • 13
6 Actuators
