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Inspection and Maintenance — GEK 107048
3. Prepare for and take clearances around the second stage nozzle.
a. With the rotor still in the forward position, position the second stage nozzle and diaphragm
(left and right) downstream by first wedging a screwdriver in the first stage shroud to second
stage nozzle outer sidewall gap. Assure that the second stage nozzle aft outer sidewall hooks
are seated downstream in the second stage shrouds, and that the second stage shrouds are
seated downstream against the turbine shell. See Figure HGP-D.5.
Second, drive a wooden wedge between the forward face of the nozzle diaphragm and the first
stage bucket shanks. Drive the wooden wedge until the diaphragm forward male hook is
seated downstream against the nozzle female hook. At this point, the wooden wedge should
be firmly in place. The downstream seated condition is indicated on Figure HGP-D.5 with
notation "These gaps must be closed."
The wooden wedge can be cut from a 2 x 4 and when possible, be made from structural grade
of wood. Dimensions of the wedge are shown in Figure HGP-D7.
Note: Do not wedge third stage nozzle and diaphragms until all second stage
nozzle area clearances have been taken.
b. Measure the "A" set point and "A" set point complements. See Figure HGP-D.8.
Measure the "A" set point, "A," between the forward flat side, not the pointed portion, of the
first diaphragm seal tooth and the aft side of the first land of the 1–2 spacer.
Measure the "A" set point complements, "A
tion of each diaphragm seal tooth and the forward side of each spacer land. Proceed with the
forward tooth first for "A
Inspection Form PGS/GT-FF-6105.
c. Measure all radial and axial clearances around the second stage nozzle. Record on Inspection
Form PGS/GT-FF-6105.
Note: 1. Do not wedge the third stage nozzles simultaneously with the second
2. Do not measure the "A" set point or complements with a snap gauge.
3. The wooden wedge is used only to maintain proper downstream
4. Prepare for and take clearances around the third stage nozzle.
a. With the rotor remaining in the forward position, position the third stage nozzles and dia-
phragm downstream similar to the second stage nozzles and diaphragms. See Figure
HGP-D.6.
" and proceed downstream for "A
C1
stage nozzles.
It is recommended to use a parallel bar and feeler stock. See Figure
HGP-D.9.
seating of the diaphragm while taking clearances. Do not drive the
wedge hard. The wedge should produce inappreciable nozzle elastic
deformation. If the wooden wedge has to be driven hard to "shock"
the diaphragm downstream, take the wedge out and drive another
wedge just until it becomes firmly in place before taking clearances.
Hot Gas Path Inspection — Disassembly Procedures
," between the aft flat side, not the pointed posi-
C
C2
," "A
," etc. Record data on
C3
HGP-D-13
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