Yorkshire Water is using waves of pressure to detect leaks in its pipes, saving the company both time and money and helping reduce water loss.
According to OFWAT, the regulatory body for water and sewage in England and Wales, the amount of UK water lost daily through leaky pipes would be enough to meet the needs of 10 million additional people. Detecting leaks, however, is a difficult process. Traditional methods, which use microphones to listen out for the sounds made by water escaping from a pipe, tend to be time-consuming and inaccurate. The recent trend towards plastic piping, in which sound rapidly attenuates, has not made this easier.
A new method, however, has been developed by researchers at the University of Sheffield. This system, which has recently been put into practical application in tests with Yorkshire Water, uses pressure waves to explore pipe networks.
A special valve is fitted to standard water hydrants. Opened and closed quickly, this generates a wave of pressure, which travels down the pipe. Whenever the wave meets a change in the network (such as a junction, turn or leak) a reflection is transmitted back up the pipe.
With knowledge of the pipe system, special analytic methods can be used, on the signals received back at the origin point of the wave, to map out the locations of these features. Comparison with previous results, therefore, can reveal the presence and location of any new leaks in the pipes.
“The system has delivered some very promising results at Yorkshire Water,” says James Shucksmith, the lecturer in Water Engineering at the University of Sheffield who led the trial of the technology.
“We are able to identify the location of leaks much more accurately and rapidly than existing systems are able to, meaning water companies will be able to save both time and money in carrying out repairs.”
During the tests, leaks in cast iron pipes were successfully pinpointed to within one metre. Tests of plastic piping proved even more effective, narrowing the search to within 20cm of the leak itself. The researchers are currently searching for an industrial partner, in order to develop the system for wider, commercial use. - Ian Randall