Method for locating and inspecting underground or other non-visible non-electrically conductive pipes

• US 6,734,674 B1
• Filed: 03/16/2001
• Issued: 05/11/2004
• Est. Priority Date: 08/14/2000
• Status: Active Grant

• Current Assignee: Daniel P. Struse, Jared H. Struse
• Original Assignee: Daniel P. Struse, Jared H. Struse
• Inventors: Struse, Jared H., Struse, Daniel P.
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Le, Toan M.
• Application Number:
  US09/809,966
• Time in Patent Office: 1,152 Days
• Field of Search: 324/326, 324/693, 324/559, 324/67, 324/637, 738/610.8, 738/611.1
• US Class Current: 324/326
• CPC Class Codes: G01M 3/18 for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005

Abstract

A method for locating and inspecting underground or other nonvisible, non-electrically conductive pipes. An electrolyte is introduced into the pipe and a time varying electrical signal is applied to the fluid as in a standard prior art method for locating underground pipes, wherein proximity to the pipe is determined by assessing the strength of the electromagnetic field produced thereby. The method also provides for detecting leaks by introducing the electrolyte relatively slowly, to ensure that a pool of the electrolyte accumulates outside the pipe adjacent the leak.

Claims

1. A method for locating a non-electrically conductive pipe or a leak therein, comprising:

introducing a flowable electrolyte into the pipe;

causing a time-varying electrical signal to propagate through said electrolyte;

detecting a resulting electromagnetic field at a plurality of locations outside the pipe; and

comparing the relative strength of said electromagnetic field at said locations for locating the pipe or leak therein.

2. The method of claim 1, wherein said electrolyte consists essentially of a saline solution.

3. The method of claim 1, further comprising providing said electrolyte as a colored dye and after completion of said step of detecting, flushing said electrolyte through an observable opening in the pipe with a fluid such that said fluid mixes with the dyed electrolyte and the change in color of said fluid and said electrolyte exiting said observable opening indicates the amount of electrolyte removed from the pipe.

4. The method of claim 3, wherein said electrolyte consists essentially of a saline solution.

5. The method of claim 1, wherein said step of introducing said electrolyte into said pipe is over a time sufficient to accumulate an amount of said electrolyte outside the pipe proximate a leak therein sufficient to detectably increase the strength of said electromagnetic field at locations nearest said leak.

6. The method of claim 5, wherein said electrolyte consists essentially of a saline solution.

7. The method of claim 5, further comprising providing said electrolyte as a colored dye and after completion of said step of detecting, flushing said electrolyte through an observable opening in the pipe with a fluid such that said fluid mixes with the dyed electrolyte and the change in color of said fluid and said electrolyte exiting said observable opening indicates the amount of electrolyte removed from the pipe.

8. The method of claim 7, wherein said electrolyte consists essentially of a saline solution.

9. The method of claim 1, further comprising providing a first opening in the pipe, introducing said flowable electrolyte into the pipe through said opening, coupling a signal lead of an electrical signal transmitting device to said electrolyte, and transmitting said electrical signal through said signal lead to said electrolyte to produce said electromagnetic field.

10. The method of claim 1, wherein said electrical signal has a frequency of at least about 1 kHz.

11. The method of claim 3, wherein said electrical signal has a frequency of at least about 1 kHz.

12. The method of claim 5, wherein said electrical signal has a frequency of at least about 1 kHz.

13. The method of claim 7, wherein said electrical signal has a frequency of at least about 1 kHz.

14. The method of claim 8, wherein said electrical signal has a frequency of at least about 1 kHz.

15. The method of claim 9, wherein said electrical signal has a frequency of at least about 1 kHz.

16. The method of claim 3, further comprising providing a first opening in the pipe, introducing said flowable electrolyte into the pipe through said opening, coupling a signal lead of an electrical signal transmitting device to said electrolyte, and transmitting said electrical signal through said signal lead to said electrolyte to produce said electromagnetic field.

17. The method of claim 16, wherein said electrical signal has a frequency of at least about 1 kHz.

18. The method of claim 5, further comprising providing a first opening in the pipe, introducing said flowable electrolyte into the pipe through said opening, coupling a signal lead of an electrical signal transmitting device to said electrolyte, and transmitting said electrical signal through said signal lead to said electrolyte to produce said electromagnetic field.

19. The method of claim 18, wherein said electrical signal has a frequency of at least about 1 kHz.

20. The method of claim 7, further comprising providing a first opening in the pipe, introducing said flowable electrolyte into the pipe through said opening, coupling a signal lead of an electrical signal transmitting device to said electrolyte, and transmitting said electrical signal through said signal lead to said electrolyte to produce said electromagnetic field.

21. The method of claim 20, wherein said electrical signal has a frequency of at least 1 kHz.