Masoneilan 72000 Series Control Valves Instruction Manual | 5
Copyright 2021 Baker Hughes Company. All rights reserved.
Plug
Cage
Plug
Cage
Figure 2 - Bell-Shaped Plug Design
Figure 3 - Straight Plug Design
Note: Many of the larger trim components are designed
with threaded lifting holes. It is recommended to use eye
bolts for ease of lifting during removal and re-assembly.
Valve Disassembly
The valve must always be reassembled with new packing
set and gaskets.
Before disassembly, make sure the
recommended spare parts are available for reassembly.
1. Disconnect the piping to the leak detector connection on the
bonnet (if applicable).
2. Remove the packing flange nuts (16) then remove the
packing flange (17) and the packing follower (18).
3. Check the exposed part of the valve stem (7) to confirm it is
clean enough for ease of removal of the bonnet (2).
4. Remove the body nuts (5).
For valve configurations designed with a two piece bonnet
assembly (bonnet and bonnet flange):
5. Disassemble the bonnet flange (3) from the valve body (1).
6. Lift the bonnet (2) and metal seal (6) to remove from the
valve body (1). During this operation, the valve stem (7)
must be pushed downward to ensure the valve plug (8)
remains inside the valve body.
Note: The metal seal (6) may require some force to remove
from the bonnet (2). Using a common tool, such as an
open-end wrench, lever the seal up at various points to lift
out evenly.
7. Remove the body gasket (25) from the top of the valve cage
(10) or (if applicable) cage retainer (11). Proceed to step 10.
For valve configurations designed with a single piece bonnet:
8. Lift the bonnet (2) and remove from the valve body (1).
During this operation, the valve plug stem (7) must be
pushed downward to ensure the valve plug (8) remains
inside the valve body (1).
9. Remove the body gasket (25) from the groove on top of the
valve body (1).
10. If applicable, remove the conical spring (14) from the
groove on top of the valve cage. Some designs for high
temperature service may include a conical spring.
11. Remove the valve plug assembly (8) from the valve cage
by pulling the valve plug stem (7) upward. In the case of
the bell-shaped plug design (see Figure 2), pulling the plug
stem (7) will remove both the plug (8) and cage (10) or (if
applicable) cage retainer (11) together. For straight plug
designs (see Figure 3), after removal of the plug (8) lift
the cage (10), and (if applicable) the cage retainer (11) to
remove from the valve body (1).
The valve plug stem is screwed, pinned and tack welded into
the valve plug (8). To disassemble the stem, the valve plug must
be held as shown below in Figure 4, taking care not to damage
the guiding surfaces. Remove tack weld if applicable and
disassemble the plug stem groove pin (24) from the assembly.
By means of flats or using a nut and counter-nut on the end of
the stem, unscrew the stem from the plug taking care not to
apply a bending movement which could deform it.
Note: For straight plug designs, as shown in Figure 3, care
must be taken to ensure the cage is not lifted out during
removal of the plug.
12. Remove the seat ring (13) by lifting the part out of the valve
body (1).
Note: The upper seat ring gasket (26) if supplied is located
on the top groove of the seat ring.
13. Remove the lower seat ring gasket (26) from the valve body (1).
14. Remove the packing set (19) and the guide bushing (20)
from the bonnet (2).
Piping Cleanliness
The valve plug assembly is screwed and pinned, and
in some cases tack welded to ensure stability and
performance. Due to the critical purpose of the plug
assembly and tolerance requirements, Baker Hughes
highly recommends avoiding in the field maintenance
of this part. The plug assembly should be purchased
as a complete assembly. However, if urgent field
repair is required, follow the instructions below.
Many of the trim components in the valve are both
large and heavy. Provisions should be made for
special lifting devices to avoid risk of injury during
maintenance. It is recommended to remove the valve
from line for easy disassembly.
