1 RG 70 en
5
downwards as impurities in the fluid may enter and dam-
age the gland packing. Any leak from the packing may then
damage the actuator. See Fig. 4.
Choose flange gaskets according to the operating condi-
tions.
Do not attempt to correct a pipeline misalignment by
means of flange bolting.
Loads on the valve body from pipeline vibrations can be
reduced by supporting the pipeline properly. Reduced
vibration also increases the lifetime of the positioner.
Where necessary, you can support the valve by the body,
using regular pipe clamps and supports. Do not fasten sup-
ports to the valve or flange bolting or to the actuator, see
Fig. 4.
3.3
Control valve assembly
Check all joints, piping and cables.
Check that the actuator stop screws, positioner and limit
switches are calibrated. Refer to their installation, mainte-
nance and operating manuals.
3.4
Valve insulation
If necessary, the valve may be insulated. Insulation must not
continue above the upper level of the valve body, see Fig-
ure 5.
4
MAINTENANCE
4.1
Maintenance general
Although Metso’s Neles valves are designed to work under
severe conditions, proper preventative maintenance can
significantly help to prevent unplanned downtime and in
real terms reduce the total cost of ownership. Metso recom-
mends inspecting the valves at least every five (5) years.
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 peri-
odic 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.
4.2
Gland packing adjustment
In the event of a packing leakage tighten the gland nuts
(18) in ¼ turn steps each until the leakage is stopped. Do
not tighten more than necessary.
Fig. 4
Installing the control valve into pipeline using sup-
ports
Fig. 5
Insulation of the valve
Insulation limit
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.
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 manu-
facturer of the type of medium used in the valve (include
material safety datasheets (MSDS)).
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.
