13 |
Baker Hughes
© 2020 Baker Hughes Company. All rights reserved.
X. Disassembly (Cont.)
Disc Seat Repair
To recondition the disc seat by lapping, it is
necessary to disassemble the disc assembly. This is
done in the following manner: The disc is contained
in the disc holder by a Truarc retaining ring; the ring
may be removed by using a Truarc Plier #4; after
removing the Truarc ring, the disc and disc collar can
be removed from the disc holder.
The disc can now be lapped using the same
procedure as described above.
If the disc is damaged to the extent that machining is
necessary, the following procedure can be used:
a. Using a four-jaw chuck, align the disc insert so
that it is running true.
b. Take light cuts on the seat surface until all
damage is removed. Reestablish dimensions as
shown in Figure 5 and Table 1.
c. When “C” dimension has been reduced to .025”
(0.64 mm), the disc insert should be replaced.
D
F
H
T
E
RETAINING
RING
X
C
B
Z
A
DISC
F
T
E
DISC
COLLER
DISC
HOLDER
G
C
G
J
D
H
Figure 5: Disc Assembly
Table 1: Disc Assembly Rework Dimensions
Valve Size
A
±.002”(±0.05 mm)
B
±.002”(±0.05 mm)
C min.
D min.
H min.
J
+.000”/-.003”
(+0.00/-0.08 mm)
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
.50
12.70
.518
13.16
.412
10.46
.025
0.64
.715
18.16
.092
2.34
N/A
N/A
.75
19.05
.669
16.99
.561
14.25
.025
0.64
.953
24.21
.117
2.97
.700
17.78
1.00
25.40
.834
21.18
.706
17.93
.025
0.64
1.192 30.28
.147
3.73
.873
22.17
1.50
38.10 1.339 34.01 1.139 28.93
.025
0.64
1.909 48.49
.222
5.64
1.400 35.56
2.00
50.80 1.680 42.67 1.465 37.21
.025
0.64
2.449 62.20
.284
7.21
1.803 45.80
Figure 5a:
Gas/Air Service: .5” to 2”(12.7 to 50.8 mm)
Liquid Service: .5” (12.7 mm)
Figure 5b:
Liquid Service: .75” to 2”
(19.1 to 50.8 mm)
