1. 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 “W” 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.
2. Spring: Check for any corrosion or pitting.
3. Standard Metal Seated Disc
: This disc (Figure
41) 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.
4. Thermodisc and Cryodisc Metal Seated Disc
:
This disc (Figure 44) 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 44 that is listed in Table 7.
b. If the dimension cannot be measured,
replace the Thermodisc.
Table 7: Thermodisc Replacement Criteria
Orifice
A min.
in.
mm
D
.006
0.15
E
.006
0.15
F
.006
0.15
G
.006
0.15
H
.006
0.15
J
.013
0.33
K
.014
0.36
L
.014
0.36
M
.014
0.36
N
.014
0.36
P
.017
0.43
Q
.015
0.38
R
.015
0.38
T
.025
0.64
U
.025
0.64
V
.035
0.89
W
.035
0.89
A
B
C
Figure 44: Thermodisc Design
Figure 44b: J-U Orifices
Figure 44c: V&W Orifices
Figure 44a: D-H Orifices
A
C
B
C
B
A
XV. Inspection and Part Replacement (Cont.)
48 |
Baker Hughes
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