6
Valve insulation
If necessary, the valve may be insulated. Insulation must not continue
above the upper level of the valve body, see Figure 10.
3.3 Actuator
The valve open/closed position is indicated as follows:
•
by an indicator on the actuator
or
•
by a groove at the end of the ball shaft (parallel to the ball flow
opening).
If there is any uncertainty about the indicator, check the ball position
by the groove.
The actuator should be installed in a manner that allows plenty of
room for its removal.
The upright position is recommended for the actuator cylinder.
The actuator must not touch the pipeline, because pipeline vibration
may interfere with its operation.
In certain cases it may be considered advantageous to provide
additional support to the actuator. These cases will normally be
associated with large actuators, extended shafts, or where severe
vibration is present. Please contact Neles’ business for advice.
3.4 Commissioning
Ensure that there is no dirt or foreign objects left inside the valve or
pipeline. Flush the pipeline carefully. Make sure that the valve is
entirely open when flushing.
Ensure that all nuts, pipings, and cables are properly fastened.
Check that the actuator, positioner, and switch are correctly adjusted.
Actuator adjustment is explained in Section 6. To adjust the
accompanying device refer to the separate control equipment
instruction manuals.
4 MAINTENANCE
4.1 Maintenance general
Although 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. Neles recommends 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 Neles
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 Neles office. The
part numbers in the text refer to the exploded view and to the parts
list in Section 10, unless otherwise stated.
4.2 Changing the gland packing
while the valve is in the
pipeline
The V-ring gland packing requires no regular tightening. The gland
packing tightness is provided by the pipeline pressure together with
gland pressure against the packing rings. In graphite gland packings,
tightness is ensured by contact between the gland follower and the
packing rings.
The gland packing (69) must be changed if leakage occurs even after
the hex nuts (18) have been tightened. The V-ring gland packing
Fig. 10
Insulation of the valve
NOTE:
When installing the actuator on the valve, make sure that the
valve package functions properly. Detailed information on
actuator installation is given in Section 6 or in the separate
actuator instructions.
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 manufacturer 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 corroded.
CAUTION:
Do not dismantle the valve or remove it from the pipeline while
the valve is pressurized!
