Mounting Into The Pipeline - Metso Neles L4 Series Intallation, Maintenance And Operating Instructions

2 L6 70 en
3.2

Mounting into the pipeline

Flush or blow the pipeline carefully before installing the
valve. Foreign particles, such as sand or pieces of welding
electrode, will damage the disc sealing surface and seat.
The valve may be installed in any position and offers tight-
ness in both directions (L6C/D, L6F/D). L6F offers tightness
in one direction.
Install the valve in the pipeline so that the shaft is horizon-
tal if possible. However, we do not recommend installing
the valve with the actuator on the underside because dirt in
the pipeline may then enter the body cavity and damage
the gland packing.
If the valve is equipped with a flow balancing trim (type
code S-...), it must be on the down stream side of the valve
body. The valve must be mounted so that the perforated
plate will not collect any impurities in the pipeline (see
Fig. 4).
Not recommended mounting position coding for valve-
actuator unit if using S-disc: A-HL, B-HL, C-HL and D-HL.
Select flange gaskets according to the operating condi-
tions.
Do not attempt to correct pipeline misalignment by means
of flange bolting.
Fig. 4. Position of the flow balancing trim
It may be necessary to firmly support the pipeline to pro-
tect the valve from excess stress. Sufficient support will also
reduce pipeline vibration and this ensures proper function-
ing of the positioner. Do not fasten supports to the flange
bolting or to the actuator.
It is recommended that the length of any straight pipe
preceding the control valve is at least 2 x pipe diameter.
The flow causes a so-called dynamic torque against the
valve disc which attempts to close the valve. In a pipe
elbow the pressure on the outer edge is higher than on the
inner edge.
When installing the triple eccentric disc valve immediately
after a pipe elbow, the valve shaft must be directed toward
the centre point of the pipe (see Fig. 5). This is especially
important when the valve is used as a control valve.
The valve shaft of a valve mounted after the centrifugal
pump must be perpendicular to the pump shaft (see Fig. 6).
When thus installed, the valve discs will be more evenly
loaded and vibrations otherwise possible in the intermedi-
ate positions will be eliminated.
When mounting the valve it must be in a closed position
and be carefully centred between the pipe flanges so that
the turning disc does not touch the pipe edge or flange
gaskets, see Fig.7 and Table 1.
Fig. 5.
Fig. 6.
The recommended
Use caution when installing valve with Spring-to-open
position of the
actuator. Valve must be in closed position during installa-
perforated plate is at
tion if the disc exceeds the Face-to-face length. Energy sup-
the "top" of the
pipeline, on the
ply for the actuator must be safely fastened and it cannot
downstream side and
suffer damage or break off during the installation.
to flow direction B.
In case of sudden shutdown of the energy supply the valve
will open unexpectedly due to pre-stressed spring package.
This may cause significant harm to people and material
Flow direction B
around the valve.
In valves with certain nominal sizes some flange bolts do
not pass the valve body. The valve body is thus equipped
with holes, see Fig. 8 and Tables 2...6.
Ensure that the disc can turn to the open position after pre-
liminary tightening of the flange bolts. The actuators of
control valves can be equipped with position stops which
usually only allow the disc to open 80°.
Lenght of stud bolts in Tables 2...6 are based on:



Fig. 7.
Mounting after a pipe elbow
Mounting after the centrifugal pump
gasket thickness of 3 mm
heavy nuts
flange thickness of weldneck flanges per ASME
Minimum pipe inside dimensions
5