| Pumps
get a new lease of life |
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Before
the Public Utilities Board (PUB) introduced its
pump refurbishment programme, they practised preventive
maintenance by replacing their pumps every 20 to
25 years. The assumption was that the pumps would
have deteriorated to an unsatisfactory level of
performance and efficiency by then.
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| A
pump before it was refurbished. |
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| The
same pump after refurbishment. |
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As there was no accurate means of measuring their
performance in-situ, and there was no known technology
to restore their performance, PUB just replaced
the pumps when they reached the end of their “useful”
lifespan. As a fact, replacing pumps at fixed intervals
is still the predominant practice in the industry
today.
Adopting a new approach
When PUB acquired know-how from an overseas supplier,
it began to consider the feasibility of implementing
a pump refurbishment programme. Subsequently, adopting
new technology, such as pump performance measuring
equipment, also contributed to the success of the
programme.
When a pump is refurbished, its physical appearance
is renewed, and more importantly, its performance
and efficiency are restored. This is akin to giving
the pump a new lease of life.
And how is this done? This is achieved by applying
a layer of performance enhancement coating on the
internal surfaces of the pump and keeping wear ring
clearances as small as possible. The former reduces
fluid friction and the latter keeps internal leakage
in the pump to a minimum.
As PUB gained more confidence in the feasibility
and viability of refurbishing pumps, it changed
its maintenance strategy from replacing big capacity
pumps every 20 to 25 years to refurbishing them.
Many benefits
The pump refurbishment programme offers many benefits.
As the lifespan of pumps is extended, replacement
and hence capital expenditure can be delayed.
Another major benefit is that PUB can now operate
its pumps at an optimal level for a longer period
by regularly monitoring their performance and refurbishing
them when the need arises. In other words, their
performance deterioration curve is much more gradual
as compared to that of a pump which has not been
refurbished. This second benefit has enabled PUB
to save substantial energy costs in its pumping
operation.
Impressive savings
The idea for the pump refurbishment programme was
first mooted in the mid-1990s. Since its successful
implementation, the “useful” lifespan
of some 56 pumps has been extended, and PUB has
enjoyed significant capital expenditure savings
of up to $12.7 m.
This year, savings in capital expenditure are estimated
at $0.6 m. This is in addition to the estimated
annual savings of $1 m in energy costs from the
refurbishment of some 126 pumps.
Over the next three years, additional savings in
capital expenditure amounting to $10.6 m can be
expected from extending the operating life of 44
additional pumps. |
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