Metso NELDISC L4 Series Intallation, Maintenance And Operating Instructions Download

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2 L6 70 en



Mount the actuator to the valve bracket with four
screws. The tightening screw of the bushing should
be loosened before mounting, to allow the shaft to
fit easily into the actuator.



The actuator construction allows axial movement of
the drive shaft to compensate the valve shaft move-
ment due to e.g. thermal expansion. Check, before
the screw is tightened, that the drive shaft is in the
upper position of its axial movement, which is its
normal position (the mounting position shown in
Fig. 23). Checking is important, as the actuator shaft
drops down slightly when the screw is tightened.
The drive shaft axial movement can be observed and
measured before attachment to a valve. The actuator
drive shaft is in the upper position when its upper
surface conforms to Table 13 (see Fig. 23).



The drive shaft will automatically find its correct
position if the installation tool H061904 (see Fig. 23)
is used. The installation tool is attached instead of
the coupling plate using M4 screws with the drive
shaft in lower position (before the valve is installed).
Tighten the nut of the tool in such a way that the
tool pulls the drive shaft to the uppermost position.
The position may be checked from the side of the
tool.



Install the actuator on the valve and attach the valve
mounting screws loosely by hand. Then tighten the
tightening screw (I) according to Table 13. The
required torque is also marked on a plate close to the
drive shaft on the actuator housing. The installation
tool is removed, and the coupling plate is reat-
tached. Finally, tighten the valve mounting screws.



Check the axial position of the drive shaft. The shaft
position may not be at the upper or lower position X
given in Table 13, or close to those values. Remount
the actuator if the position is not correct.

The valve may malfunction if the tightening of
the connection has been carried out improperly.



Finally, the extreme rotation positions of the valve
are adjusted with the adjustment screws at the ends
of the actuator. The location of the screws for adjust-
ing the close and open positions of the valve are
marked on the actuator housing (see Fig. 25). See
Section 6.7.

6.6

Detaching and installing other
actuator types

See actuator’s manual for details.

6.7

Stop screw adjustment

6.7.1

General

Close the metal seated triple eccentric disc valve by turning
the disc with a torque against the seat. Choose the torque
from Tables 14, 15, 16 and 17 for adjusting the stop screw to
the closed position of the actuator. Try not to exceed the
given values since excessive torque would strain the seat
and the joint between the disc and the shaft. Always read-
just the stop screw after changing the seat and after
mounting the actuator.

6.7.2

Actuators other than tabulated

Close the valve as per the tabulated torque Mc and adjust
the stops accordingly. Note the increased torque created by
the actuator while the valve is closed.

6.7.3

Changing the mounting position

Always remove the actuator from the valve shaft before
mounting it into another key groove. Readjust the closed
position limit as instructed.

If manually operated, the valve should close when the
handwheel is turned clockwise. In a double-action cylinder,
the piston must be in the upper position of the cylinder
when the valve is closed. In this position the actuator cre-
ates maximum torque.

Do not turn the disc more than 90°

as this could damage the seat.

Table 13. Mounting faces, tightening screws and drive shaft

clearances

Size

Mounting

Thread

Key

upper pos.

(mm)

lower pos.

(mm)