NEWS
Pressure group
Control system could help water companies meet leakage reduction targets
WATER companies struggling to
keep to leakage reduction targets
set by industry regulators could
soon be assisted by a new pressure
controlling system developed
in the UK.
Southampton-based i20 Water
has designed an electronic system
featuring a self-learning algorithm
that allows it to regulate the pressure
of a water network. The
company claims its technique, due
for launch later this year, is the
cheapest and fastest way to
reduce leakage, compared with
existing methods, which involve
digging up the road to fix leaks or
to replace pipes.
‘Both methods are very expensive
and also a lot of leaks are very
small, so it is not cost-effective to
dig up the road and fix these little
leaks. Really the only way of tackling
that leakage is by managing the
pressure better, which is what our
system does,’ said i20 Water’s
managing director Adam Kingdon.
The company’s business plan is
to achieve an average of 11 per
cent reduction in leakage, depending
on factors such as the size of
leakage and existing water pressures,
but it says that recent trials
have exceeded this goal.
‘We have been trialling [the system]
with one major water company
since January on part of its network
and we have reduced the leakage
on that bit by over 25 per cent,’
claimed Kingdon.
This result is significant when
considering how water companies
in England and Wales, according to
Kingdon, lose 3.6 billion litres of
water a day — the equivalent of 149
litres per property, per day.
At the moment, pressure in the
water network varies greatly —
from very low in the day and early
evening when many people are
using water, to very high at night
when no-one is using water. The
new technology aims to smooth the
pressure out and at the same time
reduce the average pressure in the
pipe and reduce leakage by constantly
controlling the pressure to
8
The company believes its technique is the fastest way to reduce leakage, compared with digging up the road
keep it at just the right level
depending on the area’s needs.
For the technology to work, one
part of the company’s system is
installed at the entrance (or inlet) to
a distribution network area (a zone
that would typically have up to
2,000 houses) and another component
is fitted at what the company
refers to as the ‘critical point’ —
that is the point in the network that
is furthest away from the inlet, at
the highest ground level and where
pressure is lowest.
‘At the entrance to the network
you have an existing pressure
reducing valve (PRV) that is at the
moment fixed at a certain pressure
using a big spanner. They have to
have that pressure high enough so
that during the middle of the day
when everyone is using loads of
water, it does not fall below the
legal minimum pressure of 15m,
particularly at the critical point,’
said Kingdon. Without the new
technology, Kingdon said compa-
nies find that they go below the
stipulated minimum pressure several
times each day, resulting in an
unstable service to customers.
Thus at the inlet, a pilot valve is
attached to the PRV, and this is
connected to a stainless-steel
encased electronic controller that
measures the flow rate into the PRV
and contains a self-learning algorithm
that electronically regulates
the pressure.
At the critical point, a monitoring
device comprising a pressure
transducer measures the pressure
at least once every minute (some
water companies measure the
pressure every 15 minutes on
average) and the flow rates, and
stores this data.
‘Every day, the controller PRV
side and the monitor at the critical
point connect to our server using
GPRS and download the day’s
data. Our software calculates a new
algorithm based on the data and it
automatically downloads a new
algorithm to the controller. So the
longer it is installed, the more data
it has and the better the algorithm,’
said Kingdon. The information can
then be made available to water
companies either through i20
Water’s website or directly through
its own management information
system.
A lack of power sources at the
PRV means that the most challenging
aspect of the project for
Kingdon was to make a system
with very low power consumption.
‘The system is powered by a
battery with a five-year life. Most of
the time the device is switched off
and a little part of the device monitors
the flow rates. If it goes outside
certain parameters it wakes up the
rest of the device and calculates
what the new pressure should be. If
the pressure does drop below a
fixed level or if there is a burst, it
would send an alarm to the server
and we alert the company,’ he said.
Anh Nguyen
the EnGIneeR 21 APRIL–4 MAY 2008
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