Page 45 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

30 Major Process Equipment Maintenance and Repair

3. Measure and record all shaft fits. Undersized or damaged fits
should be repaired by the procedures outlined in Volume 3 of this
series.

Case End Wall and Cover

1. Measure and record all fits between pump casing and mating parts.
2. Remove all plugs and fittings to inspect threads. Reinstall all plugs
and fittings.
3. Inspect and indicate mounting pads to ensure they are flat and par-
allel with pump centerline. Machine, if out of alignment.

Bearing Housing and Bearings
1. Observe good anti-friction bearing mounting procedures (see Vol-
ume 3 for details).
2. Ball bearings: Replace if worn, loose, or rough and noisy when ro-
tated. If dirty, clean with solvent, dry and coat with a good lubri-
cant. New bearings should not be unwrapped until ready for use.
Whenever in doubt about the condition of a bearing, scrap it. But if
the bearing is still relatively new, and feels and looks good, don’t
discard it.
3. Sleeve bearings: Check surfaces of bearing and shaft for imperfec-
tion, babbitt build-up, and hot spots. Small imperfections do not
harm the bearing. A typical diametral clearance is .0015 in. per in.
of shaft diameter. For proper operation, clearances should never ex-
ceed .003 in. per in. of shaft diameter on typical pumps.

Mechanical Seals

Refer to Chapter 8 in Volume 3 for maintenance and repair of mechani-
cal seals.

Impellers
1. Replace if excessively worn or corroded. The impeller should have
been statically and dynamically balanced at the factory, and static
and dynamic balance must be maintained for proper operation of
your equipment.
2. Inspect and measure impeller bore and if worn or deteriorated, ma-
chine true. Recondition the shaft to fit revised impeller bore size.
Refer to Volume 3 for guidance.
3. Measure outside diameter of impeller wear rings and record size.
Refer to Table 1-2 for diametral clearances.