The statistics are alarming: Up to 40 percent of fresh water flowing through supply pipes today never reaches the end consumer, but seeps out unused through leaks and into the ground. This is because many of the pipes are now over a hundred years old and correspondingly fissured. So far, there has been no cost-efficient way of detecting these leaks. Conventional high-end flow sensors, which cost 1000 to 2000 euros, are too expensive to be used throughout entire networks.
On behalf of Pisa’s water supply company Acque S.p.A., researchers at the Fraunhofer Institute for Silicon Technology ISIT in Itzehoe and their Italian colleagues at Sensordynamics have developed a cost-efficient alternative: silicon-based sensors. These only cost around five percent of the average price of their high-end counterparts. The new probes function according to the same principle as mass air flow sensors, which have been used for some time to measure the air intake in car engines. “Now we are able to use these sensors in liquids for the first time,” says ISIT project manager Dr. Peter Lange.
At the heart of the sensor are two heating wires, which are mounted one behind the other on a thin membrane. An electric current flowing through the wires heats them to a constant temperature. When cold water flows past them, the front wire gives off more heat into the water than the rear one, which is in its slipstream. Accordingly, a higher current has to flow through the front wire in order to keep the temperature constant. On the basis of this difference in electrical current, it is possible to determine the speed and volume of the water traveling through the pipes.
The special feature of this sensor is that it operates in pulse mode. The wires are not heated constantly, but only for about three seconds per minute, which means that they are cold most of the time. This helps to reduce lime deposits and air bubbles, which could otherwise distort the measurements. Another advantage of pulsed operation is that it saves energy, and the batteries last much longer. The first tests were successful: The sensors survived for three months under water without suffering any damage. For further tests, the researchers integrated 70 prototypes into Pisa’s water pipes just a few weeks ago. There, they must withstand the flow for several months at full operation, measuring how much water is traveling through the supply pipes and where it is lost. “The data can be retrieved by mobile phone or radio,” says Lange. If the tests are successful, it is perfectly conceivable that the sensors will be produced at a rate of 50,000 to 500,000 per year.
Press Office | alfa
How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
23.05.2017 | Event News
22.05.2017 | Event News
17.05.2017 | Event News
23.05.2017 | Physics and Astronomy
23.05.2017 | Life Sciences
23.05.2017 | Medical Engineering