
184 Practical Centrifugal Pumps
impeller. If the impellers become loose, there is this grave danger of a rub on
starting.
• Impellers fitted with collets in comparison to those held by splittings; keys,
snap rings, and others need a lot more attention. Excessive tightening of the
collet can lead to cracking of the impeller in the hub area.
• After the pump bowls have been assembled, the lift should be checked and the
rotor should to rotated by hand to check for any rubbing of internals
• If the length of the pump is large, column sections have to be assembled in a
horizontal position.
• The assembled positions should be rotated 180° w