Flowserve V-377 R4 Edward Valves - Manual (Page 43)

43
Flow Control Division
Edward Valves
8. Initially compress the pressure-seal
gasket, making sure that the bonnet
does not cock in the body.
9. While maintaining the pull-up load,
torque the bonnet/cover bolts evenly
using a varying star pattern, until the
fastener torques reach a value of 2/3
or the torque given in Table C on
page 42.
10. After reaching 2/3 of the torque
value given in Table C on page 42,
torque the bonnet nuts in small
torque increments, with no more
than 1/16 turn per tightening
round, using a varying star pattern,
until the full torque value given in
Table C on page 42, is reached.
11. Re-torque the bolts at the final
torque value several times, until the
gasket no longer compresses. This
step is necessary due to the high
resilience of the graphitic gasket.
12. Complete remaining valve assembly
in accordance with the appropriate
preceding section of this manual.
13. When the valve is next under pres-
sure, either during system hydrostat-
ic test or when put in service, re-
torque the bolts to the torque values
given in Table B on page 10.
CAUTION
Do not use the torque
values in Table C on page 42
while the valve is under pressure.
Introduction
The reassembly procedures in this manual
are not as detailed as the disassembly
instructions since, in many cases, just a
reverse procedure is used. However, step by
step instructions are provided for each of the
four bonnet types. In addition, the following
general points should be considered.
1. The most important consideration in
the reassembly of pressure-seal valves
is cleanliness. All flaky scales should
be removed with a wire brush, emery
cloth, or acid solvent. Oil and grease
should be removed from all parts
with a suitable solvent to prevent any
foreign matter from collecting on seal-
ing and seating surfaces.
2. Unless it is impossible to do so, use
a new pressure-seal gasket when
reassembling a bonnet that has been
disassembled, whether it was leaking
or not.
3. When reassembling valve bonnets,
always examine the stem packing
and replace if necessary.
4. Observe all of the reference marks or
prick punch marks assigned during
disassembly so that the original part
relationships can be maintained.
5. Reassemble stud nuts and cap screws
using the torque values given in Table
B on page 10.
6. When reassembling the bearings in
the yoke assembly of non-revolving
stem valves, use the following proce-
dure to obtain the proper bearing
preload:
Handwheel Operated Valves
a. Close the valve hand tight.
b. Impact the handwheel.
1) Two men, one blow for valves
with spherical roller bearings.
2) One man, one blow for valves
with tapered roller bearings.
c. Tighten the handwheel bearing
nut, using a tool to engage the two
drive holes in the top or a strap
Reassembly Procedures for Metal Pressure-Seal Valves
Assembly of Composite Pressure-Seal Gaskets
(continued)