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TM 10-4930-241-13
4-17. GATE VALVE ASSEMBLY (4-INCH) REPAIR - cont.
c.
Inspection. Refer to figure 4-6.
(1)
Inspect bonnet (10) and valve body (17) for cracks, scored mating surfaces, stripped threads and
corrosion.
(2)
Inspect for bent stem (12) and galled or stripped threads.
(3)
Inspect sealing surfaces of discs (14 and 15) and valve body ( 17) for deep scratches and cracks.
d.
Repair. Replace damaged or defective parts. Replace all sealing components.
e.
Assembly. Refer to figure 4-6.
(1)
Screw stem (12) all the way into bottom of bonnet (10), then back out stem three full turns. Do not allow
stem to move from this position.
(2)
While holding stem (12) in place, screw disc riser (16) onto stem until bottom of riser is flush with end of
stem.
(3)
Position discs (14 and 15) on disc riser (16) and install two alien screws (13).
(4)
While preventing stem (12) from turning in bonnet (10), turn discs (14 and 15) and riser (16)
counterclockwise onto stem until top of discs contact bottom of bonnet.
(5)
Position gasket (11) on valve body (17).
(6)
While holding stem (12) in position, lower bonnet (10) and discs (14 and 15) into valve body (17). Do not
rotate discs more than 1/4 turn to aline discs with body.
(7)
Install cap screws (9), lockwashers (8) and nuts (7) in valve body (17) and bonnet (10). Tighten nuts
evenly in a cross pattern.
(8)
Slide packing (6) over stem (12) and down into bonnet (10).
(9)
Slide packing gland (5) and gland spring (4) over stem (12).
(10)
Slide packing nut (3) over stem (12) and tighten onto top of bonnet (10).
(11)
Position handwheel (2) on stem (12) and secure with nut (1).
4-23
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