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Masoneilan 73000 Series control valves Instruction Manual | 7
and the upper end of plug. If the space is narrow, it can be extended by pushing down the plug or
raising the piston rod by hand-wheel operation.
6)
Dismantle the plug (13) from the bottom of the body (10).
Note: The disassembly is completed by dismantling the packings (6), packing spacer (8), lantern ring (9)
and guide bushing (7).
7)
Inspect for any damages to each component parts.
Note: As the assembly procedure for packing box may vary with the type of valve, please refer to the
respective assembly drawings.
3.2.
Polishing the Valve Seat
When the valve seat needs polishing, install the seat ring (12) and plug (13) from the bottom of the
body (10), attaching them tentatively to the body hand-tight, lightly press the plug (13) against the
seat side from the bottom of the body (10), hold the plug with a wrench applied to the wrench holder,
and polish the seating surface. Do not polish the seating surface too hard, otherwise it may be
damaged. When polishing the seating surface, apply a fine-grain, quality abrasive to it. Thoroughly
clean the seating surface prior to reinstallation.
3.3.
Reassembly
Reassemble the valve according to the following procedure after having completed the necessary
maintenance.
Please note that new packings and gaskets should be prepared for re-assembly.
1)
Clean all the gasket surfaces of the body and the seat ring.
2)
Set the guide bushing (7) toward the packing box bottom of the body (10).
3)
Insert the plug (13) from the bottom of the body (10). Set the seat ring without the gasket. Stand up
the body.
4)
Install the packings (6), packing spacer (8), and lantern ring (9), leaded by the stem of plug (13) and yet
the amount of packings and the order of packings are specified by each valve. When installing the
packings which have the cut ends, they have to be staggered 120 degrees with respect to each
other.
5)
Regarding the installation of the packing follower (4) and of packing flange (3), follow the reverse of
the disassembly procedure. Refer to the section 3-1 – point 5.
6)
Mount the actuator on the body. At this time, follow the reverse of the disassembly procedure.
Refer to the section 3-1 - point 5.
7)
Move down the piston until it stops whether by applying air pressure in the upper part of the actuator
piston or by hand-wheel operation.
8)
Couple the piston rod (19) to the plug (13) with the split clamp (18). When coupling, confirm that the
threads of piston rod and plug are completely engaged with each split clamp. It will be useful that
you were marking before disassembling.
Lightly tighten the nut (16) or bolt (26) of split clamp at the position being completely engaged.
9)
Raise the plug whether by applying air pressure to the piston bottom of the actuator or by hand-
wheel operation. At that time, the plug is kept away from the seating surface. And then rotate the
plug at a half turn counterclockwise in order to get completely the seating force. You can use the
record made at the time of disassembly to provide the seating clearance.