Flowserve V-377 R4 Edward Valves - Manual (Page 31)

AREA 3
(For a definition of Area 3, see page 18)
(See Illustration No. 5 on page 11 for an
explanation of valve parts nomenclature.)
Step-by-step disassembly procedures are
described for each of the four basic bonnet
types. For a review of bonnet types, refer
to pages 4, 5, 6 and 7. The procedures
for each bonnet type include disassembly
instructions for stop, stop-check (non-
return), and piston-lift check valves. A sec-
tion is also included under bonnet Type III
for tilting-disk check valves. The applicable
instructions should be read thoroughly
before the start of disassembly.
All of the following bonnet disassembly pro-
cedures are arranged in accordance with
the general comments on page 18. Study
these pages carefully before beginning.
Type I Pressure-Seal Bonnets – Stop
and Stop-Check (Non-Return) Valves
See Illustration No. 20 on page 27.
Note: All Type I bonnets have revolving
stems.
1. Loosen the gland bolt nuts and tap
the gland, which should relieve any
pressure that might be trapped in the
valve. This is important.
Note: Care must be taken in remov-
ing the yoke stud nuts, in case the
above step has not relieved all pres-
sure that might be trapped in the sys-
tem. Once the yoke stud nuts are
completely removed, the yoke-bonnet-
stem assembly is held only by the fric-
tion of the pressure-seal gasket
against the body bore. Trapped pres-
sure could cause these parts to be
blown out with considerable force.
Therefore, care must be taken to
break the bonnet and pressure-seal
gasket loose before the yoke stud
nuts are completely removed. 2. Remove the crossarm by tapping with
a hammer on the underside.
3. Carefully remove the yoke stud
nuts, observing the cautionary note
in step 1.
4. Remove half of the bonnet stud nuts,
alternating to leave those remaining
equally spaced.
5. Remove the gland bolt nuts.
Illustration No. 23
Type II Bonnet on Non-Revolving Stem Stop Valve
31
Flow Control Division
Edward Valves
Disassembly Procedures for Bonnet Types