Flowserve V-377 R4 Edward Valves - Manual (Page 36)

36
Flow Control Division
Edward Valves
22. On stop valves, the disk and disk-nut
assembly is attached to the stem. On
stop-check (non-return) valves, the pis-
ton-disk assembly is not attached to
the stem and must be removed sepa-
rately. See step 23.
23. Screw 1/2”-13 bolts (3/8”-16 on
sizes 5” and smaller) into the thread-
ed bosses or nuts provided in the pis-
ton. The piston can now be lifted
from the valve. Occasionally a
vacuum may be formed by the cool-
ing fluid in the pipe line below the
valve. Until relieved, this vacuum will
prevent removal of the piston. Since
the piston must be removed through
the pressure-seal area of the bonnet
bore, use caution to avoid marring
the sealing surface in any way.
24. The bonnet end opening should be
kept covered whenever possible.
Type III Pressure-Seal Bonnets –
Stop and Stop-Check (Non-Return)
Valves
See Illustration No. 24 on page 34.
*1. Mark the body, yoke and yoke lock
ring with prick punch marks so the
parts can be reassembled in their
original position.
*2. Remove the yoke lock ring studs and
nuts.
*3. Remove the yoke lock ring using a
small pry bar to separate the halves.
*4. Loosen the stem guide collar lock nut,
back off the stem guide collar lock
screw and remove the stem guide
collar key.
*5. Turn the crossarm in a direction to
close the valve, thus unscrewing the
yoke from the stem. The stem must be
restrained from turning; a flat tool
held in the stem guide collar key slot
is convenient, being careful not to
damage the slot.
*6. If the valve is installed with its stem
other than vertical, attach the chain
hoist to the yoke in such a manner as
to permit rotation of the crossarm.
*7. With the chain hoist, lift the yoke
assembly clear of the stem and body
assembly, simultaneously slipping the
stem guide collar off the stem.
8. Mark the bonnet, bonnet retainer
ring, and body with adjacent prick
punch marks so their relative position
can be duplicated in reassembly.
9. Remove the gland bolt nuts and
gland.
10. Screw an eyebolt in the threaded end
of the stem.
11. With the chain hoist mounted in line
with the stem and fastened to the eye-
bolt, pull the stem into firm contact at
the bonnet backseat.
12. Remove the bonnet stud nuts and
bonnet retaining ring.
13. With clean rags and air hose, thor-
oughly clean the top of the valve and
all exposed surfaces of the bonnet
and gasket retainer segments. This is
important.
14. Slack off the chain hoist slightly. If the
bonnet does not drop away from the
pressure-seal gasket, tap gently until
it does. When the bonnet is free,
lower it as far as it will go into the
body.
15. With a copper or brass drive pin, or
a clean hardwood block, drive the
gasket retainer segments downward
to the bottom of the retainer groove
(about 1/16”) in the body.
16. Remove the gasket retainer segments.
17. Lift the bonnet into contact with the
pressure-seal gasket, again using the
chain hoist.
18. Replace the bonnet retainer ring,
using shims to provide additional
clearance for further upward move-
ment of the bonnet.
19. Use three or four nuts in a uniform
spacing on the bonnet studs to pull
the bonnet and pressure-seal gasket
out of the body. All nuts should be
turned uniformly, a fraction of a turn
at a time using a star pattern. It is
possible to damage valve parts by
cocking the bonnet, so uniform turn-
ing of the nuts is very important.
20. Remove the stem and bonnet assem-
bly. During this process, mark the
spacer ring and pressure-seal gasket
at points (other than seal-surfaces)
corresponding to the previous mark
on the body (see step 8). In laying
the parts aside for inspection, it is
imperative that they be placed care-
fully on a bed of rags or other soft
material to avoid marring any
machined surface, particularly any
seating and sealing surfaces.
Disassembly Procedures for Bonnet Types
(continued)