When buying a centrifugal pump, carefully select the appropriate size to avoid uneconomical operation. Consider variable speed for efficiency and longevity. Ensure proper installation with adequate submergence, perpendicular suction elbows, and independent pump supports. Operate pumps within the recommended flow range and shut them down immediately if noise or vibration occurs. Maintain pumps through regular performance tests, lubrication, and using original spare parts to maximize the life of your centrifugal pump.

1. Tips for buying centrifugal pumps
Here are some important tips while buying a centrifugal pump.
Pump Selection
Avoid over sizing of your pumps as this results in uneconomical operation of
the pump. It also narrows the safe operation range of capacities of the pump.
Avoid pumps with a really low NPSH (Net Positive Suction Head) and
remember not to falsify the actual NPSH. Resorting to this leads to choosing of
pumps with excessively high suction speeds and high minimum flows.
Evaluating the advantage of variable speed operation will be useful as it is
efficient and results in longer pump life. Be careful not use a mechanical seal
when packing is more than adequate for the intended use.
Installation
Ensure adequate submergence over intake piping to prevent formation of
vortex. Suction elbows should always be placed over the in the plane
perpendicular to the shaft and not parallel. Pump casing should not be used as
an anchor for the pump. All expansion joints and supports should be anchored
independently. Providing adequate flow, pressure and temperature
instrumentation for the pump are imperative. Pump and driver alignment have
to be rechecked under normal operating conditions.
Operation
Ensure you do not operate pumps below the recommended minimum flow or
when suction valve is closed. Ensure you do not run two pumps parallel when
one pump can carry the load. Make sure that air is kept out of the pump,
pumps are made to carry liquids only. Stop the pump immediately is any
excessive noise or vibration occurs. Run spare pumps once in a while to check
their efficacy.
Maintenance
Running performance test at frequent intervals will help you to follow
increased internal clearances. Avoid opening of pumps unless any evidence
proves it necessary. Lubricating or greasing of lubricated bearings are not
necessary, avoid doing that. Packing stuffing boxes needs experienced hands,
leaving it to inexperienced hands will prove detrimental. Avoid tightening
stuffing box glands too much. Leakage needs to flow smoothly to cool and
lubricate properly. Always use original spares excepting in an emergency.
Examine and recondition your pump regularly. Look out for corrosion in your
pumps. Always new gaskets in your pumps when overhauling them.

2. Follow these steps and your centrifugal pump will serve you well for years.