Apparatus and process for measuring the magnitude of leaks

• US 5,361,636 A
• Filed: 09/23/1992
• Issued: 11/08/1994
• Est. Priority Date: 09/23/1992
• Status: Expired due to Term

• Current Assignee: Columbia Gas of Ohio Incorporated (NiSource Incorporated)
• Original Assignee: Columbia Gas of Ohio Incorporated (NiSource Incorporated)
• Inventors: Cremean, Stephen P., Farstad, Jerry E.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Ashraf, Nashmiya
• Application Number:
  US07/948,597
• Time in Patent Office: 776 Days
• Field of Search: 73/40.5 A, 73/592, 73/587, 376/252
• US Class Current: 73/592
• CPC Class Codes: G01M 3/243 for pipes

Abstract

An accelerometer is attached to a pipe wall to measure the acoustic pressure waves generated in a fluid within the pipe as a result of a leak in a valve in the pipeline. Calibrating the accelerometer and tuning it to particular wave frequencies allows a determination of the magnitude of the leak through the valve.

Claims

1. A process for measuring the fluid flow rate of a lead flowing through a valve when closed comprising,

providing a first pipe having fluid flowing in said pipe,

providing a valve which is open connected in fluid communication with said first pipe,

providing a second pipe to receive said fluid flowing from said first pipe through said valve,

closing said valve,

calculating a value of the magnitude of a leak of said fluid flowing into said second pipe through said closed valve solely by measuring one or both of (1) the vibrations of said second pipe caused by acoustic pressure waves in said fluid inside said second pipe or (2) the acoustic pressure waves in the fluid inside said second pipe, as leak measurement data.

2. The process of claim 1 including providing previously obtained leak measurement data from other valves and pipes,

comparing said measured vibrations or pressure waves in said second pipe with said provided leak measurement data to determine the magnitude of said leak into said second pipe.

3. The process of claim 2 including measuring said leak measurement data at an acoustic pressure wave frequency above about 30 kHz.

4. The process of claim 3 including inserting a probe into the second pipe interior to make said measurement of acoustic pressure waves in said second pipe.

5. The process of claim 3 including making said measurement of pipe vibrations by measuring the vibrations of the sidewall of said second pipe.

6. The process of claim 1 including making said measurement in said second pipe at an acoustic pressure wave frequency above about 30 kHz.

7. The process of claim 6 including inserting a probe into the second pipe interior to make said measurement of acoustic pressure waves in said second pipe.

8. The process of claim 6 including making said measurement of pipe vibrations by measuring the vibrations of the sidewall of said second pipe.

9. The process of claim 1 including inserting a probe into the second pipe interior to make said measurement of acoustic pressure waves in said second pipe.

10. The process of claim 1 including making said measurement of pipe vibrations by measuring the vibrations of the sidewall of said second pipe.

11. Apparatus for determining the magnitude of a leak of fluid from a first pipe flowing through a closed valve into a second pipe comprising,

a measuring instrument to detect acoustic pressure waves from fluid leaking into said second pipe,

means in said instrument for measuring acoustic pressure waves only above about 30 kHz,

means for calibrating said instrument with previously obtained data for testing of leaking fluid of a specific composition, said previously obtained that including data from (1) a third pipe having a specific wall thickness, (2) specific fluid pressures on each side of a second leaking valve between said third pipe and a fourth pipe, (3) acoustic wave measurement at a site which is a specific distance along said fourth pipe from said second valve, and (4) a specific inside diameter of said fourth pipe between said second valve and the acoustic wave measurement site,

said calibrating means including an algorithm programmed into said instrument to receive said previously obtained data, and

means for calculating and outputting from said instrument the magnitude of said fluid leaking through said valve.

12. The apparatus of claim 11 wherein the measurement of acoustic waves is in the range of about 30-40 kHz.

13. The apparatus of claim 11 wherein said means in said instrument for measuring measures the vibrations at the exterior surface of said second pipe.

14. A test instrument mounted to report data indicating the magnitude of a fluid leak flowing from a first pipe through a closed valve into a second pipe, comprising,

means for giving a signal in response to the magnitude of acoustic pressure waves caused by fluid leaking through said valve into said second pipe,

means for calibrating said instrument with previously obtained data for testing of leaking fluid of a specific composition, said previously obtained data including data from (1) a third pipe having a specific wall thickness, (2) specific fluid pressures on each side of a leaking second valve between said third pipe and a fourth pipe, and (3) a specific inside diameter of said fourth pipe, and

means for calibrating said instrument to give said signal only for an acoustic pressure wave frequency above about 30 kHz, means for calculating and reporting the magnitude of said fluid leaking through said valve.

15. The test instrument of claim 14 wherein said instrument includes a probe projecting through the wall of said second pipe to receive acoustic pressure waves emanating from the leak flowing through said valve.

16. The test instrument of claim 14 wherein said instrument includes a probe mechanically attached to the external surface of the wall of said second pipe.

17. The test instrument of claim 16 wherein said mechanical attachment is by an adhesive.

18. The test instrument of claim 16 wherein said mechanical attachment comprises a block which is silver soldered to the external surface of a wall of said second pipe.

19. The test instrument of claim 18 wherein the surface of said second pipe side wall is ground flat to accommodate a juxtaposed planar surface of said block.

20. The test instrument of claim 18 wherein the surface of said block juxtaposed to the second pipe surface is configured to accommodate the curved second pipe surface to provide a uniform spacing between said juxtaposed surfaces.