Flowserve V-378 R1 Edward Equiwedge Gate Valve - Manual (Page 24)

24
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 even-
ly using a varying star pattern, until
the fastener torques reach a value
of 2/3 the torque given in Table 7,
pg. 23.
10. After reaching 2/3 of the torque
value given in Table 7, torque the
bonnet nuts in small torque incre-
ments, with no more than 1/6 turn
per tightening round, using a vary-
ing star pattern, until the full torque
value given in Table 7 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 2, pg. 7.
CAUTION
Do not use the torque
values in Table 7 while the
valve is under pressure.
Reassembly Instructions for Valves with Composite Pressure Seal Gaskets Only
(cont.)
Reassembly Instructions for Valves with Metal Gaskets Only
Type I Pressure Seal Bonnet
See Illustration No. 7, pg. 14
1. Place one gate half on a clean ply-
wood board. Place the stem T-head
in the recess in the gate.
2. Place the gate spacer ring into the
counterbore in one gate half. Place
the other gate half on top, engag-
ing the spacer ring and stem.
Holding the gate halves together,
lift the stem and lower assembly
into the body, engaging the gate
guide rails with the grooves in the
body. Lower the gate to the seats.
3. Assemble a new pressure seal gas-
ket and the junk ring on the bon-
net. Lift the bonnet assembly over
the stem and lower it into the body.
Be very careful not to mar the pres-
sure seal gasket or other machined
surfaces.
4. Place the gasket retainer plate and
thrust washer on the body and
align cap screw holes on the gas-
ket retainer plate with the body
holes.
5. Place the bonnet retainer plate
over the stem and start threading
onto the bonnet.
6. Place the gland over the stem.
7. Place the yoke over the stem and
engage the stem threads by turning
the yoke bushing counterclockwise.
When the yoke contacts the gasket
retainer plate, align the cap screw
holes and continue to turn the yoke
bushing until the stem contacts the
backseat. This will pull the bonnet
and gasket up against the gasket
retainer and the yoke flange up
against the body.
8. Assemble the yoke flange cap
screws and tighten in a star pattern
using a torque wrench to values as
shown in Table 2, pg. 7.
9. With the bonnet retainer cap
screws flush on the bottom of the
bonnet retainer, screw the bonnet
retainer down until it contacts the
thrust washer. Now back it off