Assembly of composite pressure-seal gaskets, Edward valves, Table c – Flowserve V-377 R4 Edward Valves User Manual

Page 42

Flow Control Division

Edward Valves

It is important to determine that the new
composite pressure-seal gasket, the bonnet
and the body sealing area are in satisfac-
tory condition before installation. The fol-
lowing steps will help ensure superior per-
formance of the gasket.

1. Carefully inspect the body bore and

bonnet O.D. sealing surfaces.
Remove any raised metal from the
entry chambers and gasket chamber
regions. Repair any gouges in the
sealing region in accordance with the
instructions on page 10.

2. Inspect the new composite gasket.

Note: All composite gaskets have
cracks and wrinkles in the flexible
graphite. This is a normal result of
the forming process and will not
affect gasket performance.

3. Be sure the anti-extrusion rings are

tightly bonded to the graphitic gas-
ket, so they will not touch the body
during assembly. If any of the anti-
extrusion rings are loose, carefully
scrape away all flexible graphite left
on the anti-extrusion ring surface and
re-bond to the graphite surface using
Loctite 454 or other suitable contact
cement. The ends of the outer rings
should touch after bonding. There
should be an approximate .020 ±
.005” gap at the ends of the inner
ring.

4. Place the gasket on the bonnet with

the two anti-extrusion rings facing up
as shown in the illustration. The gas-
ket should fit snugly around the bon-
net, and the gasket O.D. should not

exceed the O.D. of the bonnet. This
will ensure that the gasket does not
catch on the body and “energize”
prematurely.

5. Install the spacer ring on the bonnet

as shown with the wide end toward
the gasket. Now the valve may be
reassembled using the assembly
procedures described in the following
sections for different types of bonnets,
except that special torqueing
procedures are required as described
in the following:

IMPORTANT: The composite pressure-seal
must remain dry until fully compacted
for proper sealing!
6. Once the bonnet and bonnet retainer

holes have been aligned, lightly lubri-
cate the fasteners with high-tempera-
ture anti-seize lubricant. Assemble the
Belleville washers under the nuts or
capscrews. Assemble remaining parts
as described in previous sections.

7. Preload the bonnet by pulling up with

a well-centered crane load or with
come-alongs.

Assembly of Composite Pressure-Seal Gaskets

BELLEVILLE

WASHERS

GASKET

RETAINER

SPACER

RING

COMPOSITE

GASKET

Table C

Composite Gasket Bonnet/Cover

Bolt/Nut Pull-Up Torques

(For Initial Pull-Up)

Bolt Size

Required Torque

ft.-lbs.

3/8

7/16

1/2

9/16

100

5/8

135

3/4

220

7/8

350

540

1-1/8

770

1-1/4

1100

1-3/8

1500

1-1/2

1700

1-5/8

2300

1-3/4

3200

1-7/8

4200

4600