3 R 71 EN - Issue 9/2020
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4.2 Replacing the gland packing
In gland packings, tightness is ensured by the contact between the
gland follower and the packing rings. See Fig. 10.
The gland packing (20) must be replaced if leakage occurs even after
the hexagon nuts (25) have been tightened.
•
Make sure that the valve is not pressurized.
•
Unfasten the nuts (25) and remove the retaining plates (42) and
the gland follower (9).
•
Remove the five old packing rings (20).
•
Clean the packing ring counterbore. Mount the new packing rings
one by one using the gland follower as a tool. Mount the retaining
plates with the text UPSIDE on top (see Fig. 10).
•
Place the nuts on the studs and tighten the gland packings (see
Table 1)
Table 1
Torques for the gland packing nuts.
The actuator may be detached to facilitate the work.
4.3 Detaching the actuator
It is generally most convenient to detach the actuator and its auxiliary
devices before removing the valve from the pipeline. If the valve
package is small or if it is difficult to access, it may be more practical
to remove the entire package at the same time.
•
Disconnect the actuator from its power source; detach the air
supply pipe and control signal cablesor pipesfrom their connec-
tors.
•
Unscrew the bracket screws.
•
Detach the actuator using a suitable extractor. The tool can be
ordered from the manufacturer.
•
Remove the bracket and coupling, if any.
4.4 Removing the valve from the
pipeline
•
Make sure that the pipeline is not pressurized and that it is empty.
Also make sure that no medium is led into the pipeline while the
valve is being removed or after it has been removed.
•
Place the hoisting ropes carefully, unscrew the pipe flange bolts
and lift the valve from the pipeline using the ropes. Note the cor-
rect lifting method. See also Fig. 6.
4.5 Replacing the seat
Detaching the seat
•
The valve must be removed from the pipeline.
•
Turn the segment (3) so that it does not touch the seat, Fig. 11.
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!
Fig. 10
Installing the retainer plates
Thread
Torque, Nm
5/16 UNC
10
3/8 UNC
20
1/2 UNC
50
CAUTION:
When handling the valve or the valve package, take its
weight into account!
NOTE:
Before dismantling, carefully observe the position of the valve in
relation to the actuator and positioner/limit switch so as to make
sure that the package can be properly re-assembled.
CAUTION:
Do not dismantle the valve or remove it from the pipeline
while the valve is pressurized!
Fig. 11
Turning the ball segment
