Flowserve V-377 R4 Edward Valves - Manual (Page 33)

33
Flow Control Division
Edward Valves
In larger sizes where this assembly is
too heavy to manhandle, remove the
cover/cover retainer and install an
eyebolt in the threaded hole in the
cover. Use the eyebolt to fasten a
chain hoist directly above the valve
centerline. In laying the parts aside
for inspection, it is imperative that
they be placed carefully on a bed of
rags or other soft material to avoid
marring any machined surface,
particularly any seating and sealing
surfaces.
6. 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. 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.
7. The bonnet end opening should be
kept covered whenever possible.
Type II Pressure-Seal Bonnets – Stop
and Stop-Check (Non-Return) Valves
with Revolving Stems
See Illustration No. 22 on page 30.
*1. Remove the crossarm by tapping with
a hammer on the underside.
*2. Mark the body and yoke with prick
punch marks so that the parts can be
reassembled in their original position.
*3. Remove the yoke stud nuts.
4. Remove the gland stud nuts and
gland.
*5. Lift the yoke and stem to clear the
studs, and spin the yoke completely
off the stem.
6. Mark the bonnet, bonnet retainer
ring, and body with adjacent prick
punch marks so that their relative
position can be duplicated in
reassembly.
7. Replace the crossarm and handwheel
nut on the stem and with a chain
hoist mounted in line with the stem,
pull the stem up snugly against the
bonnet backseat. On Limitorque-
operated valves, thread an eyebolt
into the threaded top end of the stem.
8. Loosen the bonnet retainer cap
screws.
9. Unscrew the bonnet retainer ring.
10. With clean rags and an air hose,
thoroughly clean the bonnet and
gasket retainer segments. This is
important.
11. 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.
12. With a copper or brass drive pin, or
small clean hardwood block, drive
the gasket retainer segments down-
ward to the bottom of the retainer
groove (about 1/16”) in the body.
13. Remove the gasket retainer segments.
14. Lift the bonnet into contact with the
pressure-seal gasket, again using the
chain hoist.
15. Screw back on the bonnet retainer
ring, using shims to provide addition-
al clearance for further upward
movement of the bonnet.
16. 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.
17. Remove the stem and bonnet assem-
bly. During this process, mark the
spacer ring and pressure-seal gasket
at points (other than sealing surfaces)
corresponding to the previous mark
on the body (see step 6). 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.
18. On stop valves, the disk and disk-nut
assembly is attached to the stem. On
stop-check (non-return) valves, the
piston-disk assembly is not attached
to the stem and must be removed
separately. See step 19.
Disassembly Procedures for Bonnet Types
(continued)