Vibro-Acoustic Technologies for Leak Detection Under Development in Brazil- Fabricio Almeida

The presence of a leak in water distribution systems induces vibration which is used for its detection and location. Hence, vibro-acoustic techniques together with leak detection devices have been enhanced and developed to detect leaks even in their early stages. The leak noise correlator is one of these devices often used in leak detection surveys due to its ability to pinpoint the leak position. However, this is only possible if the time delay at which the leak noise reaches two sensors placed at specific positions in the water distribution system and the leak noise velocity, are well estimated. Signal processing techniques, such as the cross-correlation function, are used to estimate the time delay in actual situations, which can be problematic when employed in plastic pipes due to the high attenuation of leak noise. Moreover, such a problem can be even worse depending upon which type of soil surrounds the buried pipe. One way to understand this phenomenon is via using models representative of the problem where different scenarios can be simulated and the physics interpreted accordingly. These models are also used to estimate theoretically the leak noise velocity used in leak noise correlators.
Based on these facts, a group of researchers in Brazil supported by the water company SABESP together with the research Foundation FAPESP have started developing technologies based on vibro-acoustic signals to aid in leak detection problems, initially focused on the enhancement of devices and signal processing involving correlation. Web based software has been developed with a user-friendly interface where leak simulations (different scenarios) can be performed; a portable test bench which can replicate the vibration of buried water pipes due to leak noise excitation generated by a model (fine control on the performed simulation) and by actual leak data; and the first Brazilian-made leak noise correlator using mainly components produced in Brazil.

Видео Vibro-Acoustic Technologies for Leak Detection Under Development in Brazil- Fabricio Almeida канала IWA Water Loss Specialist Group