Masoneilan 74000 Series Control Valves Instructions Manual | 5
Copyright 2021 Baker Hughes Company. All rights reserved.
9.
Remove the Seat Ring sub-assembly (B102), and the
second Body Gasket (B015) from the Valve Body (B001).
For valves larger than 2”, remove the Conical Spring (B013).
Inspect the Seat Ring Insert (B102b) to ensure it is free from
defects including early signs of erosion, such as scratches
and wear.
Note: The Seat Ring sub-assembly (B102) is a two-piece
assembly made up of an outer piece and an inner liner.
This assembly should be purchased as a complete
assembly.
10.
Remove the Plug/Stem sub-assembly (B119) by pulling the
stem portion through the packing box section. Inspect the
Plug/Stem sub-assembly (B119) to ensure it is free from
defects including early signs of erosion, such as scratches
and wear.
Note: Plug/Stem sub-assembly (B119) is made from
hard materials and has brittle properties. Extreme care
should be used while removing this part to prevent
chipping and breaking.
11.
Remove all of the packing box components.
12.
Thoroughly inspect all surfaces in the Valve Body (B001),
Plug/Stem sub-assembly (B119), Seat Ring sub-assembly
(B102), Venturi sub-assembly (B142), and Lower Flange
(B010) for any visual defects or damage. Carefully inspect
the dynamic sliding surfaces and the seal interface areas.
Maintenance & Repair
The purpose of this section is to provide recommended
maintenance and repair procedures. These procedures assume
the availability of standard shop tools and equipment.
Packing Box
Packing box maintenance is one of the principal tasks during
routine servicing. Tightness of the packing is maintained by
proper compression. Compression is achieved by evenly
tightening the Packing Nuts (B201) against the Packing Flange
(B213). Periodic re-tightening of the Packing Nuts (B201) may be
required to maintain proper sealing.
Care must be taken not to over tighten, as this could create
unnecessary friction preventing smooth valve operation. If
packing leakage persists after applying maximum compression,
then the packing needs to be replaced.
The valve must be isolated and the process pressure vented
prior to performing any packing box maintenance.
PTFE Packing
Kevlar
®
/PTFE, carbon/PTFE and pure PTFE packing rings are
cut in such a way that they can be replaced without having to
separate the valve plug stem from the actuator stem.
The valve should now be inverted again to a right-
side-up position to disassemble the packing box.
Inverting the valve requires pre-planning of the rigging
and lifting process. Once inverted, the valve must be
cradled in an appropriate fixture to support its weight
and provide stability during maintenance activities.
1.
Unscrew and remove the Packing Nuts (B201) and Disk
Springs (B714).
2.
Lift the Packing Flange (B213) and Packing Follower (B212)
up along the Plug Stem (B120).
3.
Using a packing puller tool, remove all packing box
components being careful not to damage the sealing surface
of the packing box or the Plug Stem (B120).
4.
Replace the Packing Rings (B207), placing the cut in each
ring about 120° apart from the adjacent ring. Press rings in
one at a time.
5.
Reassemble the Packing Follower (B212) and the Packing
Flange (B213).
6.
Tighten the Packing Nuts (B201) without over compressing
the Packing Rings (B207).
7.
Put the valve back into service and check for leakage.
8.
Tighten Packing Nuts (B201) as required.
Valve with Graphite Packing
To replace graphite packing, it is necessary to separate the Plug/
Stem sub-assembly (B119) from the actuator stem.
1.
Remove the Packing Nuts (B201) and packing Disk Springs
(B714).
2.
Lift the Packing Flange (B213) and Packing Follower (B212)
up along the Plug/Stem sub-assembly (B119).
3.
Using a packing puller tool, remove all packing box
components being careful not to damage the sealing surface
of the packing box or the Plug Stem (B120).
4.
Replace the Packing Rings (B207). Press a back-up ring
(carbon/ graphite/Inconel braided ring) into the packing box.
Next press the expanded graphite rings into the packing
area one at a time. Press an additional back-up ring into
packing area.
5.
Reassemble the Packing Follower (B212) and the Packing
Flange (B213).
6.
Tighten the Packing Nuts (B201) without overcompressing
the Packing Rings (B207).
7.
Open and close the valve several times, then retighten the
packing as required.
8.
Put the valve back into service and check for leakage.
9.
Tighten the Packing Nuts (B201) as required.
Parts Repair
Carefully examine parts for any scratches, unusual wear, or other
visual damage prior to re-assembly.
Seating Surfaces
The Seat Ring sub-assembly (B102) and valve/Stem sub-
assembly (119) seating surfaces must be completely free of
dents, scratches, wear, or other visual damage. Any seating
surfaces showing signs of minor deterioration must be replaced
with OEM parts from the factory.
Gaskets
Gasket seating surfaces must be free of dents, scratches,
corrosion, or other types of damage. Clean mating surfaces
as required and replace any non-conforming parts. Spiral
wound gaskets (B015 and B102) must always be replaced after
disassembly.
