Masoneilan 41005 Series Globe Valves with API-6A Capabilities Instruction Manual
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© 2023 Baker Hughes Company. All rights reserved.
The seat ring (13), plug and auxiliary pilot plug (20)
seating surfaces must be completely free of dents,
wear and scratches.
If the auxiliary pilot plug seat in the valve plug (15) and/or
other valve plug or seat ring seating surfaces show signs of
slight deterioration, they can be touched up on a lathe.
For all valve types, when dressing up critical surfaces, no
more than 0.25 mm (0.010”) of metal must be removed in the
case of a 50, 80 or 100 mm (2”, 3” or 4”) valve and no more
than 0.4 mm (0.015”) in the case of a 150 to 400 mm (6” to
16”) valve. Make sure that the seating angle indicated in
Figure 3 is respected.
If a slight defect exists on any of the above seating surfaces,
lapping can be envisaged, in which case the following must
be respected:
•
Spread a fine layer of high quality sealing compound on
the seating surface.
•
Put the seat ring (13) in the body, noting the angle.
•
In the case of 41305, 41505, 41605 and 41905 valves, put
the cage (16) on the seat ring.
•
In case of 41375 valves, put the stack (48) on the seat
ring and the cage (16) on the stack.
•
In the case of 41405 and 41705 valves, assemble the
valve plug, cage and stem (15)-(16)-(1).
•
In case of 41305, 41505, 41605, 41375 and 41905,
assemble the valve plug (15) and stem (1).
•
Assemble the bonnet (7) and its guide bushing (22).
•
Place an appropriate tool on the valve plug stem (1) to
turn it.
•
Lap by slightly rotating the valve plug or the auxiliary pilot
plug in alternative directions. After several rotations, lift
the valve plug, turn it 90°, and start again.
•
Lapping can be repeated, but must be limited as much as
possible so that the seat remains sufficiently narrow to
guarantee tightness.
•
Disassemble the parts, clean them and put them back,
respecting the initial angle.
5.2.3 Gasket seating surfaces
Gasket seating surface must be free of dents, scratches and
corrosion; otherwise, they will need to be repaired.
5.2.4 Seal rings and gaskets
Spiral-wound gaskets (10), (14) and (36) must always be
changed after disassembly. Seal rings (11A), (11C) or (11E)
can be reused if they are free of scratches, erosion and
corrosion.
5.2.5 Valve plug, valve plug stem
If the valve plug has to be changed, then the stem must also
be completely changed to guarantee correct pinning of the
assembly. If only the valve plug stem has to be changed,
then the valve plug can be reused.
6. Valve Reassembly
6.1 Pinning the Valve Plug Stem
The valve plug (15) and stem (1) assembly consists of a stem
threaded into the valve plug and pinned in place.
If the valve plug (15) [or the auxiliary pilot plug (20)
in the case of a 41405 valve] needs to be replaced,
it is recommended using a new stem. The hole of the original
pin in an old stem often prevents satisfactory results being
obtained and can seriously impair the mechanical strength
of the stem-valve assembly.
Assembly is carried out as follows:
6.1.1 Reference Marking on the Valve Plug Stem
Make a reference mark on the valve plug stem at a distance
“X” (Table1 and Figure 4), equivalent to the stem recess in
the valve plug.
Note:
For shouldered plug stems with two flats, the
above marking is unnecessary.
6.1.2 Tightening of the plug stem
To carry out this operation, the valve plug must be prevented
from moving by holding the plug shank with an appropriate
tool.
Screw two nuts on to the end of the new plug stem and lock
them together. Screw the valve plug stem solidly into the
plug, checking that the reference mark is level with the end
of the plug shank.
If the stem has flats, apply a torque “T” using a wrench of
dimension “E” (see Table 1).
6.1.3 Drilling the pin hole (Table 1 and Figure 4)
Note:
For this operation, it is recommended clamping
the valve plug-stem assembly by the plug shank to
avoid damaging the guiding surfaces; particular care
must be taken so that the pin hole goes through the
valve plug axis.
If the valve plug is new, drill a hole of diameter “C” at a
distance “D” from the end of the valve plug; choose the
diameter “C” from the table according to the type of pin used
(metric or English pin). If the hole is already drilled in the
valve plug, use the hole as a guide to drill through the valve
plug stem.
6.1.4 Pinning
By means of a hammer, introduce the pin into the hole.
Complete the pinning operation, taking care to ensure that the
pin is recessed by the same amount at both sides.
Using a ball tooling and hammer, caulk the pin hole edge of
the plug.
Place the assembly in the soft jaw chuck of a lathe to check
alignment of the two parts; correct any alignment defects.
Summary of Contents for Masoneilan 41005 Series
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