Edward valves, Table 7 – Flowserve V-378 R1 Edward Equiwedge Gate Valve User Manual

Page 23

Flow Control Division

Edward Valves

Reassembly Instructions for Valves with Composite Pressure Seal Gaskets Only

It is important to determine that the new
composite pressure seal gasket:, the bon-
net and the body sealing area are in satis-
factory condition before installation. The
following steps will help ensure superior
performance 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 pg. 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 bond-
ing. There should be an approxi-
mate .020 ± .005 inch 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
gasket should fit snugly around the
bonnet, 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 “ener-
gize” prematurely.

5. Install the spacer ring on the bonnet

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

IMPORTANT: The composite pressure
seal must remain dry until fully com-
pacted for proper sealing!

6. Once the bonnet and bonnet retain-

er holes have been aligned, lightly
lubricate the fasteners with high-tem-
perature 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.

BELLEVILLE

WASHERS

GASKET

RETAINER

SPACER

RING

COMPOSITE

GASKET

TABLE 7

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