Inspection And Part Replacement; Guide; Base; Cover Plate - GE Baker Hughes 2900-40 Series Maintenance Manual

XV. Inspection and Part Replacement
1. Guide Replacement Criteria:
2900-40 Series Guide should be replaced:
a. If the sliding surface is galled, pitted or scratched or
the machined gasket surfaces are damaged.
b. The "A" dimension (See Figures 26) exceeds A max. in
Table 6.
Figure 25a: D-G Orifice
Figure 25b: H-T Orifice
Figure 25: Guide (Metal Seat & Soft Seat)
Table 6: Guide Critical Dimension
Non-Bellows Guide
A max.
Orifice
in. mm
D 1.001 25.43
E 1.001 25.43
F 1.001 25.43
G 1.001 25.43
H 1.127 28.63
J 1.002 25.45
K 1.252 31.80
L 1.377 34.98
M 1.752 44.50
N 1.877 47.68
P 2.315 58.80
Q 2.315 58.80
R 2.315 58.80
T 2.315 58.80
© 2019 Baker Hughes, a GE company. All Rights Reserved.
E
C
B
C
A
D
D
E
A
C
B
Bellows Guide
A max.
Orifice
in. mm
D 0.455 11.56
E 0.455 11.56
F 0.455 11.56
G 0.501 12.73
H 0.689 17.50
J 1.002 25.45
K 1.252 31.80
L 1.377 34.98
M 1.752 44.50
N 1.877 47.68
P 2.315 58.80
Q 2.315 58.80
R 2.315 58.80
T 2.315 58.80
2. Base: Inspect general condition for cracks or holes. Look
for any corrosion issues.
3. Cover Plate: Cover Plate Should be reused if:
a. The sliding surface in the dome area is not galled,
scratched, corroded or pitted.
b. The Gasket surface is not scratched, corroded or
pitted.
4. O-Ring Retainer: Inspect surface that sits on the disc for
any corrosion or defects that might cause the disc not to
sit flush with nozzle.
5. Nozzle: Nozzle should be replaced if:
a. The seat width requires adjustment, and the
Dimension from the seat to the first thread is less
than "D" minimum on Table 2.
b. Thread sections are damaged from pitting and/or
corrosion.
c. Top of the nozzle flange and intersecting surface are
damaged from galling and/or tearing.
d. The nozzle flange thickness can change center to face
Dimensions. The minimum dimension for orifices "D"
through "P" is .672" (16.50 mm) and "Q" through "T"
orifices is .797" (20.20 mm).
Nozzle Seat Width: Using a measuring magnifying glass,
(see Lapped Nozzle Seat Widths), determine whether
the finish lapped seat surface must be machined before
lapping. If the seat can be lapped flat without exceeding
the required seat width, as indicated in Table 3 or 4, it
does not require machining.
To reduce the seat width, the 5º angle surface must be
machined. The nozzle must be replaced if the D min is
reduced below the minimum as indicated in Table 2.
6. Spring: Check for any corrosion or pitting.
7. Standard Metal Seated Disc: This disc (Figure 24)
can be machined until the T dimension is reduced to
the minimum, as listed in Table 5. The "N" minimum
dimension must be maintained as well.
8. Thermodisc Metal Seated Disc: This disc (Figure 26)
cannot be machined. It can be lapped as long as the "A"
minimum dimension has been maintained. If lapping
does not fix damaged area, part must be discarded.
The Thermodisc must be replaced if:
a. Seat defects and damage cannot be lapped out
without reducing the "A" dimension in Figure 26 that is
listed in Table 7.
b. If the dimension cannot be measured, replace the

Thermodisc.

9. O-Ring Seated Disc: The O-Ring Retainer cannot be
Consolidated 2900-40 Series POSRV Maintenance Manual | 37