Using a geophone as an actuator to estimate the velocity of leak noise propagation in buried water pipes. (15th December 2021)

• Record Type: Journal Article
• Authors: Almeida, F.C.L.; Brennan, M.J.; de Lima, F. Kroll; Iwanaga, M.K.; Scussel, O.
• Is Part Of: Applied acoustics. Volume 184(2021)
• Publication Date: 2021-12-15
• Subjects: Leak detection -- Cross-correlation method -- Leak velocity estimation -- Geophone; Acoustical engineering -- Periodicals; Periodicals; 620.2
• DOI: 10.1016/j.apacoust.2021.108251
• Languages: English
• ISSNs: 0003-682X

Abstract

Highlights: Investigation into the use of a commercial geophone as an external source of excitation for the estimation of leak noise velocity in buried water pipes. Investigation using periodic signals to drive the geophone to generate impacts onto the pipe. Comparison between excitation using an out-of-bracket leak and the geophone as an excitation mechanism. Estimation of the leak velocity in-situ using a bespoke test rig for leak detection problems. Abstract: A common way to pinpoint a leak in a buried plastic water pipe is to use a leak noise correlator. This is performed by using the time delay between two measured signals and the velocity at which such signals travel along the pipe. In this paper, an investigation is carried out into the use of a geophone in reverse, driven by an oscillating voltage. It then acts as a tapping device, exciting the wave responsible for leak noise propagation, when it is attached to an access point to estimate leak noise velocity. Two different ways of exciting the geophone were investigated. Initial tests were conducted in the laboratory to determine the effectiveness of the device in generating a force over a wide frequency range. Field tests were then carried out on a buried pipe test rig and the predominantly fluid-borne wave was generated by the tapping device, that travelled at least 7 m.