Goulds Pumps 3408 - IOM - Manual (Page 30)

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3408 IOM 03/99
MAINTENANCE OF FLOOD DAMAGED PUMPS
The servicing of centrifugal pumps after a flooded
condition is a comparatively simple matter under
normal conditions.
Bearings are a primary concern on pumping units.
First, dismantle the frame, clean and inspect the
bearings for any rusted or badly worn surfaces. If
bearings are free from rust and wear, reassemble and
relubricate them with one of the recommended
lubricants. Depending on the length of time the pump
has remained in the flooded area, it is unlikely that
bearing replacement is necessary; however, in the
event that rust or worn surfaces appear, it may be
necessary to replace the bearings.
Next, inspect the stuffing box, and clean out any foreign
matter that might clog the box. Packing that appears to
be worn, or no longer regulates leakage properly should
be replaced. Mechanical seals should be cleaned and
thoroughly flushed.
Couplings should be dismantled and thoroughly
cleaned. Lubricate the coupling with one of the coupling
manufacturer’s recommended lubricants where
required.
Any pump that is properly sealed at all joints and
connected to both the suction and discharge should
exclude outside liquid. Therefore, it should not be
necessary to go beyond the bearings, stuffing box, and
coupling when servicing the pump after flood damage.
LUBRICATION
GREASE LUBRICATION
OF BEARINGS
Grease lubricated ball bearings are packed with grease
at the factory and ordinarily will require no attention
before starting, provided the pump has been stored in a
clean, dry place prior to its first operation. The bearings
should be watched the first hour or so after the pump
has been started to see that they are operating properly.
A lithium based NLGI-2 grade grease should be used for
lubricating bearings where the ambient temperature is
above -20° F. Grease lubricated bearings are packed at
the factory with Mobilux EP No. 2 grease. Other
recommended greases are Texaco Multifak EP-2 and
Shell Alvania EP-2.
Greases made from animal or vegetable oils are not
recommended due to the danger of deterioration and
forming of acid. Do not use graphite.
In greasing anti-friction bearings, the use of high
pressure equipment is not only unnecessary, but is
actually undesirable unless used with great care. High
pressure may damage the bearings or seals, cause
unnecessary loss of grease, create a danger of
overheating due to over greasing, and produce unsightly
conditions around the bearing. Excess grease is the
most common cause of overheating. Adequate
lubrication is assured if the level of grease is maintained
at about the capacity of the bearing and 1/3 to 1/2 of the
Check alignment of pump and driver. Shim up units if
necessary. If misalignment reoccurs frequently, inspect
the entire piping system. Unbolt piping at suction and
discharge flanges to see if it springs away, thereby indicating
strain on the casing. Inspect all piping supports for
soundness and effective support of load. Correct as
necessary.
EVERY YEAR
Remove the upper half of the casing. Inspect the pump
thoroughly for wear, and order replacement parts if
necessary.
Check wear ring clearances. Replace when clearances
become three (3) times their normal clearance or when a
significant decrease in discharge pressure for the same flow
rate is observed.
See Engineering Data Section for standard clearances.
Remove any deposit or scaling. Clean out stuffing box
piping.
Measure total dynamic suction and discharge head as a
test of pump performance and pipe condition. Record the
figures and compare them with the figures of the last test.
This is important, especially where the fluid being pumped
tends to form a deposit on internal surfaces. Inspect foot
valves and check valves, especially the check valve which
safeguards against water hammer when the pump stops.
A faulty foot or check valve will reflect also in poor
performance of the pump while in operation.
NOTE: The above time table is based on the
assumption that after startup, the unit has been
constantly monitored and such a schedule was
found to be consistent with operation, as shown by
stable readings. Extreme or unusual applications
or conditions should be taken into consideration
when establishing the maintenance intervals.