XXIII. Maintenance Tools and Supplies (Contd.)
C. Lapping Tools
The following tools are required for proper maintenance
of Pilot Operated Safety Relief Valve metal seats, and
may be purchased from BHGE.
1. Ring Lap: The ring lap is used for lapping the disc
seat and finish lapping of the nozzle seat.
2. Lapping Plate: The lapping plate is used for
reconditioning the ring lap. It may also be used for
lapping the disc. One 11” (279.40 mm) diameter
plate is required for the entire line of valves (Part No.
0439004).
3. Lapping Compound: Lapping compound is used as
a cutting medium when lapping the valve seats, as
specified in Table 18.
4. Drift Pins: Two drift pins are required for the
removal of the disc from the disc holder. Refer
Figure 82 and Table 19 for Drift Pin specifications.
5. Nozzle Lap: The nozzle lap is used for lapping the
nozzle seat and has one flat side and one side with
a 5° angle. This lap guides in the bore of the nozzle;
therefore, a different size lap is required for each
valve orifice (Table 20).
6. Lifting Tools: Lifting tools are used for the removal
of upper internal parts of larger valves, as specified
in Table 21.
A
45°
B Diameter
Figure 82: Drift Pin Specifications
Table 18: Lapping Compound Types
Brand Grade Grit
Lapping
Function
Size
Container
Part
No.
Clover
1A
320
General
4 oz
199-3
Clover
3A
500
Finishing
4 oz
199-4
Kwik-
Ak-Shun
-
1000 Polishing
1 lb
199-11
2 lb
199-12
Table 19: Drift Pin Types
Orifice
A
B
Part
No.
in.
mm
in.
mm
D, E, F, G, H, J, K 1.75 44.5 .219
5.55 430401
L, M, N, P
2.50 63.5 .375
9.53 430402
Q, R
3.00 76.2 .625 15.88 430403
T, U
3.50 88.9 .875 22.23 430404
Table 20: Nozzle Lap Dimensions
Orifice
Nozzle Bore
Nozzle
Lap
Nozzle Lap
Handle
Ring Lap
1
min.
max.
in
mm
in
mm
D
.404
10.26
.409
10.39
4451501
544603
1672805
E
.539
13.69
.544
13.82
4451502
544601
1672805
F
.674
17.12
.679
17.25
4451503
544601
1672805
G
.863
21.92
.868
22.05
4451504
544601
1672805
H
1.078
27.38
1.083
27.51
4451505
544601
1672805
J
1.380
35.05
1.385
35.18
4451506
544601
1672805
K
1.650
41.91
1.655
42.04
4451507
544601
1672807
M
2.309
58.65
2.314
58.78
4451602
544601
1672809
N
2.535
64.39
2.540
64.52
4451603
544601
1672809
P
3.073
78.05
3.078
78.18
4451604
544602
1672810
Q
4.045
102.74
4.050
102.87
4451605
544602
1672812
R
4.867
123.62
4.872
123.75
4451606
544602
1672812
T
6.037
153.34
6.043
153.49
4451607
544602
1672813
U
6.685
169.80
6.891
175.03
None
None
1672813
V
8.000
203.20
8.005
203.33
None
None
6267201
W
10.029
254.74
10.034
254.86
None
None
4875201
Note 1: Ring Laps: One set of three (3) ring laps is recommended for each orifice to assure ample flat laps are
available at all times.
Consolidated 2900 Series POSRV Maintenance Manual
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© 2018 Baker Hughes, a GE company. All Rights Reserved.
