Khalifa A., Chatzigeorgiou D., Youcef-Toumi K., Khulief Y. and Ben-Mansour R., “Quantifying Acoustic and Pressure sensing for In-pipe leak detection,” ASME International Mechanical Engineering Congress & Exposition, 2010 (original) (raw)
Related papers
Quantifying Acoustic and Pressure Sensing for In-Pipe Leak Detection
Volume 13: Sound, Vibration and Design, 2010
Experiments were carried out to study the effectiveness of using inside-pipe measurements for leak detection in plastic pipes. Acoustic and pressure signals due to simulated leaks, opened to air, are measured and studied for designing a detection system to be deployed inside water networks of 4-in pipe size. Results showed that leaks as small as 2 l/min can be detected using both hydrophone and dynamic pressure transducer under low pipe flow rates. The ratio between pipe flow rate and leak flow rate seems to be more important than the absolute value of leak flow. Increasing this ratio resulted in diminishing and low frequency leak signals. Sensor location and directionality, with respect to the leak, are important in acquiring clean signal.
In-pipe Acoustic Characterization of Leak Signals in Plastic Water-filled Pipes
Acoustic emissions can be sensed to identify and localize leaks in water pipes. Leak noise correlators and listening devices have been reported in literature as successful approaches to leak detection but they have practical limitations in terms of cost, sensitivity, reliability and scalability. A possible efficient solution is the development of an in-pipe traveling leak detection system. It has been reported that in-pipe sensing is more accurate and efficient since the sensing element can be very close to the sound source. Currently in-pipe approaches are limited to large leaks and larger diameter pipes. Development of such a system requires clear understanding of acoustic signals generated from leaks and their variation with different pipe loading conditions, leak sizes and surrounding media. This paper discusses the acoustic characterization of leak signals in controlled environments. A lab experimental setup was designed and built in which measurements were taken from inside 4 ...
Empirical evaluation of acoustical signals for leakage detection in underground plastic pipes
MELECON 2014 - 2014 17th IEEE Mediterranean Electrotechnical Conference, 2014
In this paper, an empirical evaluation of acoustical signals for leakage detection and quantification in underground plastic pipes for main water distribution networks is presented. Several experiments have been carried out to collect acoustic signals generated from various leakage volumes. Upon signals analysis, it is noticed that the acquired signals are so weak and they are buried in the background noise caused by fluid flow, specially for small leakage volumes. In this work, a simple and easy to implement method for detecting and quantifying leakages in underground plastic pipes is developed. In this method, sound data are sampled and frequency spectrum of the acoustic signals is obtained by calculating the Fast Fourier Transform (FFT). Detection and quantification of existing leakages are carried out using the integral of the spectrum over frequencies below 500 Hz. The results obtained are very useful in cases where remote detection and quantification of existing leakages in underground plastic pipes are needed.
Sensors, 2014
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
Characterization of In-Pipe Acoustic Wave for Water Leak Detection
Volume 8: Mechanics of Solids, Structures and Fluids; Vibration, Acoustics and Wave Propagation, 2011
This paper presents experimental observations on the characteristics of the acoustic signal propagation and attenuation inside water-filled pipes. An acoustic source (exciter) is mounted on the internal pipe wall, at a fixed location, and produces a tonal sound to simulate a leak noise with controlled frequency and amplitude, under different flow conditions. A hydrophone is aligned with the pipe centerline and can be re-positioned to capture the acoustic signal at different locations. Results showed that the wave attenuation depends on the source frequency and the line pressure. High frequency signals get attenuated more with increasing distance from the source. The optimum location to place the hydrophone for capturing the acoustic signal is not at the vicinity of source location. The optimum location also depends on the frequency and line pressure. It was also observed that the attenuation of the acoustic waves is higher in more flexible pipes like PVC ones.
Acoustic emissions can be sensed to identify and localize leaks in water pipes. Leak noise correlators and listening devices have been reported in literature as successful approaches to leak detection but they have practical limitations in terms of cost, sensitivity, reliability and scalability. A possible efficient solution is the development of an in-pipe traveling leak detection system. It has been reported that in-pipe sensing is more accurate and efficient since the sensing element can be very close to the sound source. Currently inpipe approaches are limited to large leaks and larger diameter pipes.
A novel sensor for measuring the acoustic pressure in buried plastic water pipes
Journal of Sound and Vibration, 2006
Acoustic techniques are widely used to locate leaks in buried water pipes. However, difficulties are often encountered when attempting to detect a leak in a plastic pipe, as the leak noise signals attenuate very rapidly away from the leak. Identifying suitable sensors which can be easily deployed and are sufficiently sensitive has been problematic. Polyvinylidene fluoride (PVDF) wire ring sensors have been proposed and demonstrated successfully in laboratory conditions previously. Here it is proposed that the ring sensor is used in a modified configuration: a flexible hose instrumented with the ring sensor is connected to the pipe, via a fire hydrant or other standard access point. Some theoretical modelling has been carried out, which predicts that the acoustic pressure in the main pipe transmits well into the sidebranch, whilst the pressure in the main pipe is largely unaffected. This suggests that PVDF wire located on the sidebranch will effectively monitor the pressure in the main pipe. Moreover, if the sidebranch is sufficiently flexible, substantial sensitivity gains can be made using this configuration compared with locating the wire on the main pipe. Measurements made in the laboratory on a medium density polyethylene (MDPE) finite pipe with a polythene sidebranch connected to it confirm that the acoustic pressure in the main pipe can indeed be measured on the sidebranch. The expected sensitivity gains were not fully realized, and a number of different reasons for this are proposed.
On the role of vibro-acoustics in leak detection for plastic water distribution pipes
Procedia Engineering, 2017
Leaks have been detected and localized in water distribution in many countries for years, by using the cross-correlation of pipe vibration measured either side of a suspected leak and/or by using listening sticks. However, in modern plastic pipes this is problematic because of the strong coupling between the water and the pipe which results in significant attenuation of the coupled fluid-pipe wave, which in turn is responsible for the propagation of leak noise. Hence leak noise does not propagate as far as it did in older metallic pipes. This paper discusses how the vibro-acoustic behavior of the water-pipe-soil system influences leak noise propagation. To investigate this, a numerical model is developed, and the results are compared with those from an analytical model for two water pipe systems, one in the UK and one in Brazil. Experimental results are also presented. It is shown that the important difference between the two systems is the shear stiffness of the surrounding soil, which has a profound effect on both the speed of leak noise propagation and the attenuation of the noise along the pipe.
Detecting & Locating Leaks in Water Distribution Polyethylene Pipes
2010
Abstract—This paper focuses on the problem of detecting and locating the position of water leaks in water distribution Medium Density Polyethylene (MDPE) pipes using passive acoustic detection methods. A leaking water pipe generates noise which depends primarily on water pressure, pipe characteristics and the leak size and shape. This leak noise comprises vibration and acoustic signals, which can be detected using non-invasive accelerometers and invasive hydrophone sensors respectively.