Flowserve LPNV Worthington - Manual (Page 36)

LPNV USER INSTRUCTIONS ENGLISH 87900031 – 06/14
Page 36 of 48
6.8.5 Shaft
When the pump is dismantled, examine the shaft
carefully. Its condition should be checked at the
impeller hub fit, under the shaft sleeve and at the
bearings.
The shaft may become damaged by rusting or pitting
because of leakage along the shaft at the impeller or
shaft sleeve.
Check the shaft keyway for distortion.
Excessive thermal stresses or corrosion may loosen
the impeller on the shaft and subject the keyway to
excessive shock. Replace a shaft that is bent or
distorted. Check a shaft that has been repaired for
possible runout (maximum 0.050 mm).
The shaft sleeve is subject to wear and may require
replacement, depending on the severity of service.
Replace it if grooved, pitted or worn.
6.8.6 Gaskets and O-rings
After dismantling, discard and replace.
The gasket must be of the same material and of the
same thickness as the original gasket
6.8.7 Bearings
6.8.7.1 Bearing bushing
If the bearing bushing shows wear upon inspection it
should be replaced. Worn bearings can cause pump
vibration and can result in damage to the wearing
rings and mechanical seal.
The bearing bushing is pinned to bearing cover to
prevent its rotation.
6.8.7.2 Antifriction bearings
Anti-friction bearings are shrunk on the shaft guide
bushing and a pulling device must be used to
remove them. The pulling jaws or fingers must be
located behind the shoulder of the inner race.
Unless extreme care is used when
removing an anti-friction bearing, the bearing
may be damaged to the extent that is no longer
useable.
Always check the bearing immediately after
removal for any imperfections or any play
between the races. It is recommended that new
bearings be used for replacement of removed
bearings since very often damage caused by
removal cannot be detected until the pump is put
into operation.
When mounting anti-friction bearings on the pump
shaft guide bushing remember that the satisfactory
operation of anti-friction bearings requires that the
inner be firmly held on the bushing so that it cannot
turn on the bushing.
Heat the bearing to expand the inner race and shrink
it on the bushing.
Place bearings on a shelf in a temperature
controlled oven. A temperature of 80° for one half
hour should be sufficient.
Care must be taken to keep the bearing clean and
uncontaminated.
Check the position of the bearing on the bushing
with a feeler gage to make sure it is pressing firmly
against the shoulder.
6.8.8 Wear rings
Impeller wearing rings are pressed into place and
held by set screws. To remove these rings for
replacement it is necessary to remove the recessed
screws and pry off the rings using wedges of some
other suitable device. Care must be exercised to
make sure the impeller is not damaged during this
operation. Preferably remove rings by mechanical
turning.