PC multimedia-based leak detection system for water transmission and distribution pipes

A method for determining the location of a leak in a pipe comprising the steps of:

• providing first and second sensor means operably connected to said conduit for generating signals related to sensing vibrations of said conduit;
• recording said signals as a function of time;
• determining the time difference between arrival of vibrations which generate signals at said first sensor means and said second sensor means, respectively, by
• subjecting a plurality of multiple point consecutive time records for each signal to fast Fourier transform analysis of the time domain data to produce auto spectra values of said first sensor signal, Gaa, and said second sensor signal, Grr, respectively;
• calculating the cross spectra values, Gar, of the respective series of time records of said first and second signals, respectively;
• summing the auto spectra values and the cross spectra values and determining averages of each, respectively;
• calculating the impulse response over a finite range by determining the inverse Fourier transform of the ratio of the averaged cross spectra to the averaged auto spectra of at least one of said auto spectra over a finite range;
• determining a peak value of such resultant values from time=0 to determine said time difference;
• and
• determining the location of said event based on said time difference and the acoustic velocity of a stress wave in the pipe.

A method of detecting leaks in pipes comprising the steps of:

• listening to a leak in a fluid pipe using an acoustic sensor to form leak signals from a first location and from a second location simultaneously to provide first and second signals respectively, the first and second location separated by a known distance of pipe;
• digitising the leak signals using a sound circuit within a personal computer, sound circuit introducing significant noise into the signals;
• and,
• calculating a leak location within the pipe using a method of calculation that reduces effects of the noise introduced by the sound circuit and absent a step of filtering the leak signals.

A method of detecting leaks in pipes comprising the steps of:

• listening to a leak in a fluid pipe using an acoustic sensor to form a leak signal from a first location to provide a first signal,
• digitising at a first sampling rate the leak signal using a sound circuit;
• and,
• playing the leak signal at a second different sampling rate than the rate at which it was digitised in order to shift sounds at inaudible frequencies to frequencies at which they are audible.