title: On the acoustic filtering of the pipe and sensor in a buried plastic water pipe and its effect on leak detection: an experimental investigation.
abstract: Acoustic techniques have been used for many years to find and locate leaks in buried water distribution systems. Hydrophones and accelerometers are typically used as sensors. Although geophones could be used as well, they are not generally used for leak detection. A simple acoustic model of the pipe and the sensors has been proposed previously by some of the authors of this paper, and their model was used to explain some of the features observed in measurements. However, simultaneous measurements of a leak using all three sensor-types in controlled conditions for plastic pipes has not been reported to-date and hence they have not yet been compared directly. This paper fills that gap in knowledge. A set of measurements was made on a bespoke buried plastic water distribution pipe test rig to validate the previously reported analytical model. There is qualitative agreement between the experimental results and the model predictions in terms of the differing filtering properties of the pipe-sensor systems. A quality measure for the data is also presented, which is the ratio of the bandwidth over which the analysis is carried out divided by the centre frequency of this bandwidth. Based on this metric, the accelerometer was found to be the best sensor to use for the test rig described in this paper. However, for a system in which the distance between the sensors is large or the attenuation factor of the system is high, then it would be advantageous to use hydrophones, even though they are invasive sensors.
authors.affiliation: Department of Mechanical Engineering, UNESP - FEIS, Av. Brasil, 56, 15385-000, Ilha Solteira, Brazil. fabricio.lobato@yahoo.com.br.
authors.forename: Fabrício
authors.initials: F
authors.lastname: Almeida
authors.affiliation: Department of Mechanical Engineering, UNESP - FEIS, Av. Brasil, 56, 15385-000, Ilha Solteira, Brazil. mjbrennan0@btinternet.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Brennan
authors.affiliation: Institute of Sound and Vibration Research-ISVR, University Road, SO17 1BJ, Southampton, UK. pfj@soton.ac.uk.
authors.forename: Phillip
authors.initials: P
authors.lastname: Joseph
authors.affiliation: South Staffs Water plc, Green Lane, Walsall WS2 7PD, UK. stuartwhitfield@south-staffs-water.co.uk.
authors.forename: Stuart
authors.initials: S
authors.lastname: Whitfield
authors.affiliation: Hydrosave Ltd, Swallow Court, Venture Park, Kettering NN15 6XX, UK. sdray@hydrosave.co.uk.
authors.forename: Simon
authors.initials: S
authors.lastname: Dray
authors.affiliation: Department of Mechanical Engineering, UNESP - FEIS, Av. Brasil, 56, 15385-000, Ilha Solteira, Brazil. tabone@dem.feis.unesp.br.
authors.forename: Amarildo
authors.initials: A
authors.lastname: Paschoalini
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D010969:Plastics; D014881:Water Supply
chemical_list: D010969:Plastics