Page 115 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

100 Major Process Equipment Maintenance and Repair

9. Repeat Steps 4 through 8 to size the split rings for each succeeding
stage.

10. When the pump bowl assembly has been completed, remove the
capscrew and locating plug, and the spacer for the first-stage im-
peller, if used. Note: Some pump designs utilize shims to position
the impellers so that remachining of the split rings is not neces-
sary. Figures 2-25 through 2-27 show further details.

Maintenance and Repair of Shafts

Most vertical multistage pumps have wearing surfaces on the shaft un-
der the bowl bearings, bottom bearings, column bearings, tension nut
bearings and packing. If the impellers are collet mounted there is very
little machining labor in the shaft, and worn shafts generally are replaced
rather than repaired. Unless provided with shaft sleeves, worn line shafts
are turned end for end to provide new journals when line shaft bearings
are replaced. Large shafts or shafts with extensive machining can be built
up using hard chrome plating or metalizing. A grinding operation then
assures that the shaft is round, smooth and within tolerance prior to rein-
stallation.

Figure 2-25. Removing a series case to expose the top of an impeller. (Courtesy Byron
Jackson Pump Division, Borg-Warner Industrial Products, Inc.)