Remote pipeline acoustic inspection

• US 20050210960A1
• Filed: 11/28/2002
• Published: 09/29/2005
• Est. Priority Date: 11/30/2001
• Status: Active Grant

• Current Assignee: University of Manchester
• Original Assignee: The Victoria University of Manchester
• Inventors: Smith, David, Shamout, Mohammad N, Turner, John T, Lennox, Barry
• Granted Patent: US 7,266,992 B2
• Time in Patent Office: Days
• US Class Current: 73/40.50A
• CPC Class Codes: G01M 3/243 for pipes

Abstract

A pipe inspection apparatus comprising an acoustic source (3) for location at a first position in a pipe or pipe network, one or more acoustic or pressure detectors (4) for location at one or more positions in the pipe or pipe network, means for recording and/or displaying a signal detected by the one or more detectors following the generation of an acoustic pulse, and means for allowing the comparison of the detected signal with a predetermined reference signal, differences between the detected and reference signals being indicative of a blockage or leakage in the pipe or pipe network (10).

Claims

1. A pipe inspection apparatus comprising an acoustic source for location at a first position in a pipe or pipe network, one or more acoustic or pressure detectors for location at one or more positions in the pipe or pipe network, means for recording and/or displaying a signal detected by the one or more detectors following the generation of an acoustic pulse, and means for allowing the comparison of the detected signal with a predetermined reference signal, differences between the detected and reference signals being indicative of a blockage or leakage in the pipe or pipe network.

2. A pipe inspection apparatus according to claim 1, wherein the apparatus comprises two acoustic or pressure detectors, the detectors being spaced apart to allow determination of the direction of propagation of a detected acoustic signal.

3. A pipe inspection apparatus according to claim 2, wherein the apparatus includes processing means for processing the detected signal such that only acoustic signals propagating in a particular direction are recorded and/or displayed.

4. A pipe inspection apparatus according to claim 3, wherein the processing means is arranged to delay by a predetermined time period a signal detected by a first one of the detectors, and subtract the delayed signal from a signal detected by a second one of the detectors, the predetermined time period corresponding to the time taken for an acoustic signal to travel between the first and second detectors, such that the combined signal comprises acoustic signals propagating in a particular direction only.

5. A pipe inspection apparatus according to claim 4, wherein the processing means is arranged to remove unwanted spectral components from the combined signal by iteratively taking values from the combined signal, delaying the values by the predetermined time period, and adding the delayed values to the combined signal to generate a revised combined signal, wherein the iteration begins at small time values of the combined signal and moves to progressively larger time values of the combined signal.

6. A pipe inspection apparatus according to claim 1, wherein the apparatus includes timing means arranged such that only acoustic signals detected during a particular time interval are recorded and/or displayed.

7. A pipe inspection apparatus according to claim 1, wherein the acoustic source comprises a pulse generator arranged to generate pulses which substantially exclude a predetermined range of frequencies.

8. A pipe inspection apparatus according to claim 7, wherein the pulse generator is arranged to generate a square wave pulse.

9. A pipe inspection apparatus according to claim 8, wherein the frequency components of the square wave pulse are selected so as to substantially exclude the predetermined range of frequencies.

10. A pipe inspection apparatus according to claim 7, wherein the substantially excluded predetermined range of frequencies corresponds at least in part to frequencies of noise present in the pipe or pipe network.

11. A pipe inspection apparatus according to claim 1, wherein the apparatus further comprises a signal filter connected between the detectors and the recording and/or displaying means, the filter being arranged to block a predetermined range of frequencies.

12. A pipe inspection apparatus according to claim 11 wherein the predetermined range of frequencies blocked by the filter corresponds at least in part to the range of frequencies present in the background noise observed in the pipe section or the pipeline network.

13. A pipe inspection apparatus according to claim 1, wherein the reference signals comprise signals recorded during previous inspection of the pipe section or pipeline network.

14. A pipe inspection apparatus according to claim 1, wherein the reference signal is based upon knowledge of the acoustic transfer function of the individual components of the pipe section or pipeline network.

23. A pipe inspection apparatus according to claim 9, wherein the substantially excluded predetermined range of frequencies corresponds at least in part to frequencies of noise present in the pipe or pipe network.

15. A method of pipe inspection comprising locating an acoustic source at a first position in a pipe or pipe network, locating one or more acoustic or pressure detectors at one or more positions in the pipe or pipe network, recording and/or displaying a signal detected by the one or more detectors following the generation of an acoustic pulse, and comparing the detected signal with a predetermined reference signal, differences between the detected and reference signals being indicative of a blockage or leakage in the pipe or pipe network.

16. A pipe inspection method according to claim 15, wherein the method further comprises using two spaced apart acoustic or pressure detectors to determine the direction of propagation of a detected acoustic signal.

17. A pipe inspection method according to claim 16, wherein the method includes processing the detected signal such that only acoustic signals propagating in a particular direction are recorded and/or displayed.

18. A pipe inspection method according to claim 17, wherein the method further comprises delaying by a predetermined time period a signal detected by a first one of the detectors, and subtracting the delayed signal from a signal detected by a second one of the detectors, the predetermined time period corresponding to the time taken for an acoustic signal to travel between the first and second detectors, such that the combined signal comprises acoustic signals propagating in a particular direction only.

19. A pipe inspection method according to claim 18, wherein the method further comprises removing artefacts from the combined signal by iteratively taking values from the combined signal, delaying the values by the predetermined time period, and adding the delayed values to the combined signal to generate a revised combined signal, wherein the iteration begins at small time values of the combined signal and moves to progressively larger time values of the combined signal.

20. A method according to claim 15, wherein only signals detected within a predetermined time interval following generation of an acoustic pulse are recorded and/or displayed.

21-22. -22. (canceled)