Method and means of passive detection of leaks in buried pipes

• US 4,289,019 A
• Filed: 10/30/1979
• Issued: 09/15/1981
• Est. Priority Date: 10/30/1979
• Status: Expired due to Term

• Current Assignee: United States Department of Energy
• Original Assignee: United States Department of Energy
• Inventors: Claytor, Thomas N.
• Primary Examiner(s): Goldberg, Gerald
• Assistant Examiner(s): Roskos, Joseph W.
• Application Number:
  US06/089,346
• Time in Patent Office: 686 Days
• Field of Search: 73/40.5 A, 73/40.5 R
• US Class Current: 73/40.50A
• CPC Class Codes: G01M 3/243 for pipes

Abstract

A method and means for passive detection of a leak in a buried pipe containing fluid under pressure includes a plurality of acoustic detectors that are placed in contact with the pipe. Noise produced by the leak is detected by the detectors, and the detected signals are correlated to locate the leak. In one embodiment of the invention two detectors are placed at different locations to locate a leak between them. In an alternate embodiment two detectors of different waves are placed at substantially the same location to determine the distance of the leak from the location.

Claims

1. A method of detecting the location of a leak in a buried pipe that contains a fluid, the method comprising the steps of:

detecting acoustic waves of a first particular type produced by the leak and propagated to a first location;

detecting acoustic waves of a second particular type produced by the leak and propagated to a second location;

transmitting the detected acoustic waves from the second location to the first location; and

determining a cross-correlation between the detected acoustic waves from the first location and the detected acoustic waves from the second location;

which cross-correlation is a measure of the location of the leak with respect to the first and second locations.

2. The method of claim 1 wherein the first and second particular types of acoustic waves are longitudinal acoustic waves.

3. The method of claim 1 wherein the first and second particular types of acoustic waves are torsional acoustic waves.

4. A method of detecting the location of a leak in a buried pipe that contains a fluid, the method comprising the steps of:

detecting longitudinal acoustic waves at a measuring location;

detecting torsional acoustic waves at the measuring location; and

determining a cross-correlation between the detected longitudinal acoustic waves and the detected torsional acoustic waves,

which cross-correlation provides a measure of the location of the leak with respect to the measuring location.

5. An apparatus for detecting a location of a leak in a buried pipe containing a fluid through the use of acoustical signals produced in the fluid by the escape of fluid at the leak, the apparatus comprising:

a first detector of acoustic waves disposed in acoustical contact with the pipe at a first location;

a second detector of acoustic waves disposed in acoustical contact with the pipe at a second location;

means connected to the second detector for communicating a signal detected by the second detector to the first location; and

means responsive to a signal from the first detector and to the communicated signal from the second detector for measuring cross-correlation between the signals,

which cross-correlation is interpretable to indicate the distance of the leak from the first and second locations.

6. The apparatus of claim 5 wherein the first and second detectors are detectors of longitudinal acoustic waves.

7. The apparatus of claim 5 wherein the first and second detectors are detectors of torsional acoustic waves.

8. The apparatus of claim 5 wherein the means for measuring cross-correlation comprise an electronic cross-correlator having a visual display.

9. An apparatus for detecting a location of a leak in a buried pipe through the use of acoustical signals produced in the fluid by the escape of fluid at the leak, the apparatus comprising:

a detector of longitudinal acoustic waves disposed at a measuring location;

a detector of torsional acoustic waves disposed at the measuring location; and

means connected to the detectors of longitudinal and torsional acoustic signals for obtaining a correlogram of signals detected by the detectors,

which correlogram provides a measure of distance from the measuring location to the leak.