TM 10-4320-345-13
4-21. GATE VALVE ASSEMBLY (4-INCH) REPAIR - cont.
Disassemble gate valve Refer to figure 4-12.
(6)
Remove nut (1) and handwheel (2) from stem (13).
(7)
Remove packing nut (3), gland spring (4), packing gland (5) and packing ring (6) from top of
bonnet (11).
(8)
Remove eight nuts (7), lockwashers (8), screws (9) and fiat washers (10) from valve body (18)
and bonnet (11).
NOTE
If needed, tap bonnet with mallet to loosen sealing surfaces.
(9)
Remove bonnet (11), gasket (12), and attached parts from valve body (18).
(10)
Remove two screws (14) and separate discs (15 and 16) from disc riser (17).
(11)
Remove disc riser (17) from stem (13).
(12)
Unscrew stem (13) from bottom of bonnet (11).
b.
Cleaning
(1)
Wash all components with clean water and detergent.
(2)
Rinse components in clean water and dry with wiping rag.
c. Inspection
(1)
Inspect bonnet (11) and valve body (18) for cracks, scored mating surfaces, stripped threads and
corrosion.
(2)
Inspect for bent stem (13) and galled or stripped threads.
(3)
Inspect sealing surfaces of discs (15 and 16) and valve body (18) for deep scratches and cracks.
(4)
Inspect male coupling (6, figure 4-11) for cracks and corrosion
(5)
Inspect female coupling (14) for cracks and broken locking arms
d.
Repair. Replace damaged or defective parts Replace all sealing components
4-46
