Force
– Two Piece Trunnion
Mounted Ball Valve
Document Number:
Revision:
Release Date:
EDC 514
A
05/09/2022
IOM: Installation, Operation and Maintenance Manual
37/43
Ⅶ. Disassembly and Reassembly
1.4
Disassembly
1.4.1
Before disassembly, partially open the valve and loosen the plug to reduce the internal
pressure trapped inside of the valve to a safe level. After having confirmed reduction of the
internal pressure to a safe level, remove the plug and drain the line fluid and other internal
residue remaining inside the valve.
1.4.2
Ensure the ball is in fully closed position.
1.4.3
Remove the gear box.
1.4.4
Untighten the body/end cap nuts (#31) and disassembled the end cap
1.4.5
Untighten the gland bolt (#32) and remove the gland flange (#11).
1.4.6
Remove the gland plate and the stem together with the stem bearing and other adjacent
parts.
If it is difficult to remove these parts, make use of the threaded tap on top of the stem and follow
the procedure:
(1)
Firmly screw a bolt into the threaded tap on top of the stem and secure it with a nut.
(2)
Assemble a wooden board, pipe, steel plate, washer and nut.
(3)
Tighten the nut clockwise to easily remove the upper stem from the body.
1.4.7
Remove the end plate. Pull out the sub-assembled small parts first, and then the bottom
stem.
The stem and trunnion is also provided with threaded tap for easier removal.
1.4.8
Place the valve on a sturdy, flat surface with the body flange facing to the floor.
(1)
Loosen the cap nuts evenly and alternately in a star pattern until the seat springs
lose their loading force.
(2)
Remove the nuts after the seat springs lose their loading force.
(3)
Some of the ball valves, depending on their size and nominal pressure, are provided
with lifting lugs mounted with flange bolting. As lifting lugs are factory-mounted at the
most convenient locations, be sure to mark their locations during disassembly for easier
subsequent reassembly.
Lift out the body cap slowly, confirming that the seat retainer and its sub-assembly,
which has been housed with the body cap, is now exposed on the ball. If the seat
retainer sub-assembly is still attached to the body cap, lightly hammer the body cap to
detach the seat retainer sub-assembly. Never leave the seat retainer sub-assembly within
the body cap. If it is difficult to remove the seat retainer sub-assembly, lift out the body
cap carefully not to drop off the seat retainer sub – assembly and place it on a surface
with the seat retainer facing upside then remove the seat retainer.