Flowserve V-377 R4 Edward Valves - Manual (Page 44)

44
Flow Control Division
Edward Valves
wrench on the O.D. Use a reason-
able length of bar stock, or ade-
quate size strap wrench, so the nut
is firmed up well.
d. Tighten the set screws in the hand-
wheel bearing nut against the yoke
bushing. This completes the pre-
loading of the lower bearing.
e. If desired, the valve can now be
closed tightly for a seat joint test.
f. To preload the upper bearing,
open the valve fully to the bonnet
backseat so it is hand tight.
g. Repeat step b.
h. Loosen the set screws in the hand-
wheel bearing nut.
i. Repeat step c. Attempt to line up
the existing set screw holes in the
handwheel bearing nut with those
in the yoke bushing. This will dupli-
cate the original factory preload.
However, it is important that the
preloading be performed as
described above and if the holes
cannot be lined up, new ones
should be drilled and tapped.
When drilling, be careful that no
chips enter the yoke bushing-stem
threads.
j. Refasten the safety wire.
Limitorque Motor-Operated Valves
This preloading procedure applies
only to the yoke bearings (on non-
revolving stem valves) on valves using
operators of the ‘torque-only’ type.
Valves using torque and thrust units
do not have bearings (they are in the
operator instead). For an explanation
of the various operator types, refer to
the section “Procedure for Removing
Limitorque Operators from Valve
Yokes” on page 22.
a. Turn the manual handwheel on the
Limitorque operator to apply 10%
of the handwheel torque required
to seat the valve against maximum
pressure.
b. Tighten the yoke bushing nut so the
keyways in the yoke bushing and
the nut line up, and insert the key.
This completes the preloading of
the lower bearing.
c. If desired, the valve can now be
closed tightly for seat joint test.
d. To preload the upper bearing,
open the valve full to the bonnet
backseat.
e. Repeat step a.
f. Remove the key, retighten the yoke
bushing nut and reinsert the key, as
in b.
g. Drive the rollpin into the yoke
bushing nut to fix the position of
the key.
7. When threading a yoke bushing
back onto the stem threads, particu-
larly on non-revolving stem valves
with heavy operators attached to the
yoke assembly, use caution in order
to not damage the threads. Start the
stem threads by rotating the hand-
wheel and keeping the weight on the
hoist.
8. When reassembling handwheels with
Impactogears, make certain that the
pinion gear meshes properly with the
large gear on the underside of the
handwheel before tightening the
bearing nut. After the bearing nut is
properly tightened, in accordance
with Step 6 above, retighten the lock-
ing screws and install the safety wire.
Type I Pressure-Seal Bonnets – Stop
and Stop-Check (Non-Return Valves)
See Illustration No. 20 on page 27.
1. Insert the disk, disk-nut, stem assem-
bly, or the disk-piston and stem, low-
ering carefully until they rest on the
valve seat. Hold the stem centrally in
the valve bore.
2. Install a new pressure-seal gasket on
the bonnet and lower this assembly
carefully into the body until it rests on
top of the stem back seat or disk-piston.
3. Lower the yoke into position, rotating
the stem the amount necessary to
engage the yoke bushing threads.
4. Turning the stem in a direction to
open the valve, raise the bonnet and
pressure-seal gasket up into contact
with the yoke.
5. Install and tighten the yoke stud nuts
using the torque values on page 10.
Reassembly Procedures for Metal Pressure-Seal Valves
(continued)