Metso L12 Series, Installation Maintenance And Operating Instructions

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2 L12 71 en 7
3.2.2 Valve insulation
If necessary, the valve may be insulated. Insulation must not
continue above the upper level of the valve body, see Fig-
ure 9.
3.3 Actuator
When installing the actuator on the valve, make sure that
the valve package functions properly. See instructions for
installing in Section 6.3
Observe the space needed for removal of the actuator.
The upright position is recommended for the actuator cyl-
inder.
The actuator must not touch the pipeline, because pipeline
vibration may damage it or interfere with its operation.
In some cases, e.g. when a large-size actuator is used or
when the pipeline vibrates heavily, supporting the actuator
is recommended. Please contact Metso’s Automation busi-
ness for further information.
4 COMMISSIONING
Ensure that no dirt or foreign objects are left inside the
valve or pipeline. Flush the pipeline carefully. Keep the
valve 30–40° open during flushing.
When starting up the pump, ensure that the valve in the
pipeline is closed or, at the very most, 20° open.
A waterhammer, which follows the start-up of high-capac-
ity pumps, creates a torque peak in the disc. This can dam-
age the pin connection between disc and shaft when the
valve is 30–90° open.
The gland packing may leak after long storage. Tighten
both nuts in the packing evenly until the leakage stops.
5 MAINTENANCE
5.1 Maintenance general
Triple eccentric disc valves require no regular maintenance.
However, check the packing regularly for tightness. If the
valve should require maintenance for some reason, a few
simple service measures are normally sufficient.
The inspection and maintenance interval depends on the
actual application and process condition.
The inspection and maintenance intervals can be specified
together with your local Metso experts. During this periodic
inspection the parts detailed in the Spare Part Set should
be replaced.
Time in storage should be included in the inspection interval.
Maintenance can be performed as presented below. For
maintenance assistance, please contact your local Metso
office.
The part numbers in the text refer to the exploded view and
to the parts list in Section 9, unless otherwise stated.
5.2 Removing the valve from the pipeline
It is generally most convenient to detach the actuator and
its auxiliary devices (see Section 6) before removing the
valve from the pipeline. If the valve package is small or diffi-
cult to access, it may be more practical to remove the entire
package at the same time.
Ensure that the valve is not pressurized and the pipeline is
empty. Ensure that the medium cannot flow into the sec-
tion where servicing is to take place. The valve must be in a
closed position when removing.
Support the valve carefully with a hoist. Place ropes carefully
and unscrew the pipe flange bolts. Ensure that the ropes are
positioned correctly. Lift valve correctly (see Fig. 3).
5.3 Replacing the gland packing
PTFE rings are used as a standard gland packing and graph-
ite rings for high temperature constructions. Tightness is
ensured by contact between the glandfollower and the
packing rings.
Fig. 9 Insulation of the valve
CAUTION:
Observe the safety precautions mentioned in Section
1.8 before maintenance!
CAUTION:
When handling the valve or the valve package as a
whole, bear in mind the weight of the valve or the
entire package.
CAUTION:
For safety reasons the retaining plates MUST
always be installed acc. to section 5.3.
Insulation limit
NOTE:
When sending goods to the manufacturer for repair, do
not disassemble them. Clean the valve carefully and flush
the valve internals.
For safety reasons, inform the manufacturer of the type of
medium used in the valve.
NOTE:
In order to ensure safe and effective operation, always use
original spare parts to make sure that the valve functions
as intended.
NOTE:
For safety reasons, replace pressure retaining bolting if the
threads are damaged, have been heated, stretched or cor-
roded.
CAUTION:
Do not dismantle the valve or remove it from the pipe-
line while the valve is pressurized!
CAUTION:
Do not dismantle the valve or remove it from the pipe-
line while the valve is pressurized!