RS – Multi-Stage, I-280
Centrifugal Pump 280 – 16.03.EN
36
NOTE
Rotate pump to a vertical standing position
using a fixture that holds the suction casing
feet. This provides proper axial impeller
alignment. This eliminates sag and helps with
figuring compression due to the tie rod
torqueing.
Replace the same number of interstage sleeve
gaskets (73G) during assembly that were
removed during disassembly after the rotor TIR
was completed per Section XI, Paragraph D,
step 10.
IMPORTANT: Assemble shims/gaskets in the
order they were disassembled only if no
sleeves or impellers were replaced.
14. Slide first stage impeller (2A) onto shaft (6) from
outboard end, fitting keyway of impeller to
impeller key (32A) on shaft.
NOTE
Check alignment in accordance with Table 3,
Axial Impeller Alignment Control Dimensions.
15. Install interstage sleeve (58) on shaft (6) from
outboard end.
16. Lubricate and install new O-ring (89D) onto
suction casing (9). Check to make sure wear
ring and diffuser bushing (63) are in diffuser
(5A). Install new lubricated O-ring (89D) in
groove provided on interstage casing (111).
Lightly tap diffuser into interstage casing.
Confirm diffuser is sitting flat and the return
vanes are missing nub in interstage casing.
17. Install interstage casing (111) assembly [diffuser
(5A), wear ring (7X), diffuser bushing (63), wear
ring (7B), and interstage sleeve (58)] over shaft
(6) and fit onto suction casing (9). Confirm
interstage casing drain plug is oriented on the
bottom of pump and that the interstage casing
assembly is sitting flat.
18. Install impeller key (32A) into keyway on shaft
(6).
19. Install impeller (2X).
20. Check impeller (2X) alignment in accordance
with Table 3.
21. Install interstage assembly [diffuser (5A), wear
ring (7X), diffuser bushing (63), wear ring (7B),
and interstage sleeve (58)] onto previous
interstage casing (111). Confirm interstage
casing is sitting flat.
22. Repeat steps 18 through 21 for each stage up
to the N
th
stage [“N” depending on the number
of stages of the pump (A,B,C,D, or E)]
NOTE
Refer to Figure 11, the front shroud of the
impeller at the base of the wear ring surface
hits on the previous stages interstage wear ring
after the N
th
stage (Refer to Table 17) and the
correct Axial Impeller Alignment cannot be
achieved ( +/- .010” ). The impeller/wear ring
interference is due to the approximately .003”
compression of each interstage casings when
tightening the tie rods.
23. When there is no impeller/wear ring clearance
there will be a gap between the impeller (2X)
and sleeve (58) (Refer to Table 17). This gap
must be measured and taken into consideration
for the Axial Impeller Alignment setting.
a. Measure the gap by leaving out sleeve (58)
and install impeller (2X).
b. Take a measurement the same way as
checking for Axial Impeller Alignment and
document.
c. Remove impeller and install sleeve.
d. Retake the measurement to see if sleeve is
holding impeller up off of the previous
interstage wear ring - this measurement
should be more than the previous
measurement and check for Axial Impeller
Alignment.
e. If measurement is not higher, then remove
impeller and add a .010” shim (73G),
reinstall impeller and retake measurement
and see if Axial Impeller Alignment
measurement increases.
f. Continue adding and counting shims until
measurement increases.
g. Repeat for remaining stages.
NOTE
Every gap that is left in the stack-up to achieve
that stage final axial impeller alignment will
compound to every stage after it and will have
to be subtracted from all final axial impeller
alignments.
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