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XVI. Reassembly of the 2900-40 Main Valve (Cont.)
Figure 14) as was used during disassembly, then carefully
lower it into the Base.
8.
Using a small amount of Silicone Grease supplied with
soft goods replacement kit, rub a small amount on the
seals and O-Rings prior to assembly.
9.
Take the Main Valve Piston and measure and cut
diagonally the proper length of Guide Ring material to fit
in the groove of the Main Valve Piston. Allow 1/16 of an
inch (1.59 mm) gap between the ends for proper fit.
10. For Teflon seals make sure of the integrity of the Teflon
seal and seal spring. Install Disc Seal on Disc outside
diameter on the opposite end of the disc seat as shown in
Table 12: Torque Required for Each Round of
Round
1
2
3
4
5
Figure 28.
If an O-Ring seal is used, it is installed in the groove
between where the Guide Ring is installed and where a
Spring Energized Seal would be installed (Figure 28).
11. Install the Guide Ring(s) onto the Main Valve Piston.
If there is more than one Guide Ring, stagger the cut
locations 180° apart.
12. To prevent seal damage during assembly, check the
chamfer on the bottom of the Cover Plate for burrs. If any
sharp edges exist, polish the chamfer.
13. Insert Main Valve Piston (energize seal/O-Ring side first)
into bottom of Cover Plate. Continue pushing Main Valve
Piston into Cover Plate, being careful not to pinch the
guide rings. Push Main Valve Piston in until bottom of
Main Valve Piston is even with the bottom of the Cover
Plate.
14. Install 1/4" MNPT pipe plug into Cover Plate where dome
line connects.
15. Install Cover Plate Gasket. Install Cover Plate on top of
Base such that the pilot will be aligned for proper tubing
connections. Make note of the length of the studs. The
two longer ones will straddle the vertical line of the inlet
sensing port on the Main Base of the pilot valve. Install
42 | BHGE
Pattern
Percentage of Required Torque
Wrench Tight
25
60
100
100
3
1
4
Holes
2
4
1
5
3
8
8
Holes
7
4
2
6
13
17
9
3
11
19
16
8
Figure 29: Bolt Tightening Patterns
the bracket between the Cover Plate and the Nut or Cap
Screw. Be sure that the bracket is aligned so that the two
smaller pilot attachment holes are above the horizontal
plane of the Cover Plate.
16. Remove pipe plug from Cover Plate.
17. Torque to the values found in Table 11 using the torque
patterns in Figure 29 and Table 12.
18. Once the Main Valve is assembled before any tubing is
connected reach through the hole in the center of the
Cover Plate and force the Main Valve Piston down until
it contacts the Disc Holder. Failure to complete this
procedure will prevent the Main Valve from loading and
closing, when pressure is applied to the valve.
19. The Main Valve is ready to receive the pilot and finished
assembly.
© 2019 Baker Hughes, a GE company. All Rights Reserved.
1
3
6
6
Holes
5
4
2
5
1
9
7
3
11
12
Holes
4
12
8
10
2
6
5
1 7
15
20
12
20
Holes
4
10
18
14
2
6
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