Andy Cruse of ERIKS explains how an organised action plan,
incorporating regular analysis, maintenance and condition
monitoring, can help to maximise pump efficiency

Where pumps are concerned, the
best way to make savings is by
finding ways to control whole life
costs. The purchase price of a pump
generally represents no more than 5% of its
total life cost and so any plan to enhance
overall pump efficiency must be based on
achieving the best energy efficiency.

The good news is that there are many
steps that can be taken to increase energy
efficiency and by combining these methods
into an organised pump action plan you can
make a big difference to plant performance.

Key pump performance data, including
calculations of head and flow, system
resistance, power use, and efficiency, can be
rendered on a graph to provide valuable
information; for example, a centrifugal pump
usually displays a rising rate power
characteristic and so considering a graph
that clearly displays this characteristic will
help determine at what level you risk
overloading the motor. Precise pump data
can also identify problems that can then be
directly addressed; for example, reduction in
flow may indicate corrosion and scale buildup
in the pump casing, or increased running
clearances.

Pump maintenance needs to be regular
and informed. We estimate that
maintenance costs are less than 10% of a
pump’s lifetime cost but good maintenance
can significantly improve efficiency and
minimise energy expenditure.

Wear and tear is unavoidable but in
pumps, where abrasive particles and poor
water quality lead to erosion and corrosion,
attention to the most vulnerable areas can
maximise efficiency. For example, wear to
the neck rings leads to an increase in
clearance. This in turn causes leakage and
recirculation from the high pressure area of
the pump casing back to the suction side of
the impeller. The result of this is reduced
head and flow, which is a constant cause of
poor energy efficiency if not managed
correctly.

A clear action plan can help you manage
these issues and enable the implementation
of a scheduled maintenance regime that is
suitable for the needs of your operations. To
help identify some key steps in the process,
we’ve put together the following summary of
things you should consider.

Begin by estimating the energy cost of
running your pumps and first focus on the
equipment that uses the highest level of
energy. It may be possible to retrofit energysaving
features, the costs of which can soon
be recovered by efficiency gains. Stage two of
your action plan should be to introduce
efficient condition monitoring practices,
routine checking and data logging of pump
performance. This should be followed by
repairs and refurbishments, such as the
application of wear resistant coatings, and
the replacement of leaking seals.

Having attended to urgent requirements
and put in place measures to monitor and
maintain your pump equipment, you can
then plan further ahead by spreading a basic
knowledge of pumping principles and
energy-saving initiatives among engineers.

Of course, a fully detailed action plan
would be far more specific than the one
described above but our summary illustrates
the framework and key considerations of
such a plan. You can either implement an
action plan yourself or enlist the help of a
specialist supplier such as ERIKS; the cost
will be repaid through the resulting savings
in energy costs and in most cases that cost is
repaid swiftly. Considering that, in some
applications, energy costs for pumps can
actually rise to as much as 95% of the whole
life cost, there are huge savings to be made
through more efficient pump operation and
more effective maintenance.

By following a strong action plan, you will
be able to optimise your equipment and keep
it optimised into the future to obtain
maximum energy efficiency.