Flowserve IJ, Installation Operation & Maintenance

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IJ PUMP OPERATION AND MAINTENANCE MANUAL
5-3 BO2660-01
5.1.2 SECOND LISTING
In the following listing, the causes of vibration and their corrections are given in the order in which
they are apt to occur:
Cause of Vibration Correction
Insufficient liquid at inlet impeller caused by
low liquid level
Using discharge valve, reduce capacity until
normal liquid level is restored
Insufficient liquid at inlet impeller caused by
release of air or vapors in the inlet
Vent pump to reestablish full capacity. Then, if
trouble continues, check for vapor pockets in
suction line, sufficient NPSH available, and
complete submergence of end of suction line
in liquid at vessel. Vapor is drawn into suction
line if end is not completely submerged.
Correct condition in suction line, as required
Misalignment (vibration appears steady) Check alignment of pump and driver and correct,
as required (see ALIGNMENT
ACCURACY). Then check suction and
discharge lines for proper bracing and
adequate provisions for expansion, making a
very careful check if misalignment is frequent.
Correct line installation, as required
Loose foundation bolts Tighten bolts, check level and alignment, and
correct, as required (see ALIGNMENT
ACCURACY).
Loose driver or pump holddown bolts Tighten bolts, check alignment, and correct, as
required (see ALIGNMENT ACCURACY).
Worn or loose bearings (vibration appears
steady)
Check bearings and replace, as required.
Out-of-balance rotor (vibration appears
intermittent)
Removing rotating assembly and check each
impeller for clogged passages and damage.
Remove foreign material from passages, repair
or replace impeller and rebalance, as required.
Bent Shaft Remove shaft, check with dial indicator,
straighten, and recheck with dial indicator for
straightness. Should first check indicate that
shaft is straight, check for worn or loose
bearings and replace as required.
Unsound foundation Reinforce foundation. A fabricated structure is
more apt to cause vibration than a concrete
foundation.
Vibration transmitted from driver to pump Disconnect coupling and run driver at full speed.
If driver vibrates, follow its manufacturer’s
instructions for corrective action
Line surges caused by improperly installed or
worn control valve transmitted to pump
Relocate control or repair valve