Spectral Analysis For Detection Of Leaks In Pipes Carrying Compressed Air

Pipe networks constitute the means of transporting fluids widely used nowadays. Increasing the operational reliability of these systems is crucial to minimize the risk of leaks, which can cause serious pollution problems to the environment and have disastrous consequences if the leak occurs near residential areas. Considering the importance in developing efficient systems for detecting leaks in pipelines, this work aims to detect the characteristic frequencies (predominant) in case of leakage and no leakage. The methodology consisted of capturing the experimental data through a microphone installed inside the pipeline and coupled to a data acquisition card and a computer. The Fast Fourier Transform (FFT) was used as the mathematical approach to the signal analysis from the microphone, generating a frequency response (spectrum) which reveals the characteristic frequencies for each operating situation. The tests were carried out using distinct sizes of leaks, situations without leaks and cases with blows in the pipe caused by metal instruments. From the leakage tests, characteristic peaks were found in the FFT frequency spectrum using the signal generated by the microphone. Such peaks were not observed in situations with no leaks. Therewith, it was realized that it was possible to distinguish, through spectral analysis, an event of leakage from an event without leakage. Copyright © 2013, AIDIC Servizi S.r.l.3213631368Avelino, A.M., Paiva, J.A., Silva, R.E.F., Araujo, G.J.M., Real time leak detection system applied to oil pipelines using sonic technology and neural networks (2009) 35th Annual Conference of IEEE 2009, pp. 2109-2114Bersani, C., Citro, L., Gagliardi, R.V., Sacile, R., Tomasoni, A.M., Accident occurrence evaluation in the pipeline transport of dangerous goods (2010) Chemical Engineering Transactions, 19, pp. 249-254. , DOI: 10.3303/CET1019041Bistafa, S.R., Acoustics applied to noise control (2006) Edgard Blucher, , São Paulo, Brazil (in Portuguese)Garcia, F.M., Quadri, R.A., Machado, R.A.F., Bolzan, A., Analysis of time/frequency for vibroacoustic detection of leaks of petroleum and gas industry (2010) Brazilian Congress of Chemical Engineering 2010, pp. 5745-5753. , in PortugueseKim, M.S., Lee, S.K., Detection of leak acoustic signal in buried gas pipe based on the time-frequency analysis (2009) Journal of Loss Prevention in the Process Industries, 22, pp. 990-994Shibata, A., Konichi, M., Abe, Y., Hasegawa, R., Watanable, M., Kamijo, H., Neuro based classification of gas leakage sounds in pipeline (2009) Proceedings of International Conference on Networking, Sensing and Control, pp. 298-302Souza, A.L., Cruz, S.L., Pereira, J.F.R., Leak detection in pipelines through spectral analysis of pressure signals (2000) Brazilian Journal of Chemical Engineering, 17, pp. 4-