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Masoneilan 48000 Series Top Guided Globe Valve | 5
A. Screwing Stem to Plug
•
Hold the plug (with vise jaw assembly) in a vise.
•
Lubricate the plug stem thread and other contact surface
with plug.
•
Lock two nuts against each other on the end of the new plug
stem, and screw the stem solidly into the plug using a
wrench on the upper nut. When properly assembled, the
shoulder of the plug stem should be contact with the top
surface of the plug.
B. Drilling the new Parts
Drill the stem to the same diameter (Diameter B in Figure 6)
as the plug shank hole.
C. Pinning the Plug-Stem assembly
Note:
Staking type plug-stem pin is standard in the 48000
Series design and it is imperative that a new
plug-stem pin be
inserted into the drilled hole.
1.
Apply a small amount of grease on the pin and hand
assemble it into the hole in the plug.
2.
Both ends of the pin must be expanded to outward by
using the special staking tool shown in Figure6.
3.
After the plug has been pinned, it should be placed in
a lathe to ensure it is concentric with the stem.
If the assembly is not running true, then the stem should be
placed in a collet with the plug guide against it and the plug
should be adjusted. Alignment of plug stem can be performed
by means of a soft faced mallet.
Replacing existing Stem only
A.
Removing existing Pin and Stem
1.
Place the plug on a V-block and use a drift punch to
drive out the old pin.
Note:
If it is necessary to drill out the pin, use a drill
bit slightly smaller than the pin diameter.
2.
Hold the plug guide in a vise.
Note:
While pinning is being performed, care must be
taken not to damage the seating surface or plug guide.
Always use a soft metal or plastic vice jaws with
cylindrical features to hold the plug guide area (see Figure
6).
3.
Lock one nut against another at the end of the plug
stem.
Using a wrench on the lower nut, unscrew the stem from
the plug. The stem is removed by turning it counter-
clockwise.
B.
Screwing Stem to Plug
Refer to step B of the previous section on “REPLACING
PLUG AND STEM”.
C.
Drilling the new Stem
Place the plug on a V-block and use a suitable size drill bit
to drill the stem (use the hole in the plug as a guide).
D.
Pinning
Note:
Staking type plug-stem pin is standard in the
48000 Series design and it is imperative that a new plug-
stem pin be inserted into the drilled hole.
Ensure plug stem alignment following the pinning
operation.
8.3 Packing Box (figures 5 and 7)
Packing box maintenance is one of the principle action
items of routine servicing. Tightness of the packing is
maintained by packing compression. Compression is
achieved by evenly tightening the packing flange nuts (3)
against the packing flange (4). Care must be taken not to
over tighten as this could prevent smooth operation of the
valve. If all compression is used up and the valve leaks, then
new packing is required.
Valve must be isolated and the pressure vented before
performing packing box maintenance.
Note:
Flexible graphite packing rings replacement
may require disconnecting the plug stem from the
actuator stem and removal of the actuator if rings are not
skive cut.
A.
Remove actuator from the body S/A. Refer to 6.2
to 6.5 of the previous section.
B.
Loosen and remove packing flange nuts (3).
C.
Remove packing flange (4) and packing
follower (5) from the plug stem.
D.
By means of a hooked instrument, remove
packing (6) ensuring not to damage the sealing
surfaces of the packing box or plug stem.
Note:
On valves equipped with an optional lubricator
connection, the lantern ring (20) must also be removed to
gain access to lower packing rings.
E.
Replace new packing set (6); first assemble a
back- up ring (Graphite Filament Yarn braided
ring), then the flexible graphite rings (smooth
rings), and finally another braided back-up
ring (refer to Figure 5).
Note:
Assemble and compress rings one at a time into
packing box.
Note:
On valves equipped with an optional lubricator
connection, refer to Figure 6 for correct arrangement
according to valve size.
F.
Assemble packing follower (5) and packing
flange (4).
G.
Assemble and tighten packing stud nuts (3).
Do not over-tighten.
H.
Proceed to appropriate instructions for
actuator and valve assembly adjustment.
I.
Place valve back in service and only tighten
packing as necessary to stop external leakage.
Содержание Masoneilan 48000 Series
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