AN APPARATUS FOR DETECTING LEAK OF FLUID FROM A LONG PIPELINE FOR TRANSPORTING FLUID

• US 3,814,207 A
• Filed: 04/25/1972
• Issued: 06/04/1974
• Est. Priority Date: 04/26/1971
• Status: Expired due to Term

• Current Assignee: Niichi Nishiwaki, Takazo Kusuda
• Original Assignee: Niichi Nishiwaki, Takazo Kusuda
• Inventors: Kusuda, Takazo, Nishiwaki, Niichi
• Primary Examiner(s): Feinberg, Samuel
• Assistant Examiner(s): Doramus, J. V.
• Application Number:
  US05/247,474
• Time in Patent Office: 770 Days
• Field of Search: 181/.5LD 73/40,4.5R,4.5A,69 340/242
• US Class Current: 73/40.50A
• CPC Class Codes: F16L 2101/30 Inspecting, measuring or testing
• CPC Class Codes: G01H 3/12 by electric means G01H3/14 takes precedence
• CPC Class Codes: G01M 3/243 for pipes

Abstract

A system for systematically detecting a leak of fluid from a long pipe comprising a plurality of apparatuses like microphones set at relatively large intervals within a relatively long limited space, formed by utilizing the wall of the pipe like a space within the pipe and extending longitudinally of the pipe. The apparatuses intercept sonic waves caused by the leak of fluid from the pipe propagated in the limited space. The system further includes an apparatus for detecting that at least one firstmentioned apparatus has intercepted the sonic wave caused by the fluid leak.

Claims

1. An apparatus for symmetrically detecting a leak of fluid from a pipe of a long pipeline useful in transporting fluid comprising, in combination:

a. a long hollow space defined, at least on one side by a wall of said pipe for transport of the fluid, which space extends longitudinally along said pipe;

b. a plurality of stationary first means for intercepting sonic waves propagated within said hollow space, said first means being propagated within said hollow space, said first means being in longitudinally spaced apart relationship to one another along said pipe over a long distance, adjacent two of said first means being spaced apart by such a distance as to enable at least one of said adjacent two of said first means to intercept a sonic wave caused by a leak which may occur at least between said adjacent two of said first means; and

c. second means coupled, via respective coupling means, to each of said first means including at least said adjacent two of said first means and responsive to their output signals for signaling that a sonic wave caused by a leak has been intercepted by at least one of said first means, said second means being positioned externally from said hollow space, and including third means, which includes a first unit for computing the leak point based upon the relative relationship between at least two signals sent from respective ones of said first means of said plurality of first means, and a second unit coupled to said first unit and responsive to output therefrom for indicating the cOmputed result.

2. An apparatus as set forth in claim 1, wherein said second means is disposed at a single place, and each of said first means is coupled to said second means via a respective one of said coupling means.

3. An apparatus as set forth in claim 1, wherein said hollow space is an interior space of said pipe.

4. An apparatus as set forth in claim 1, further comprising a wall surrounding said pipe over a considerable distance along said pipe and wherein said hollow space is a space formed between said pipe and said wall.

5. An apparatus as set forth in claim 1, wherein each said first means of said plurality of first means responds to the intensity of any intercepted sonic wave for producing a signal indicative of the sonic wave exceeding a predetermined level, which level occurs upon occurrence of a leak of fluid from said pipe.

6. An apparatus as set forth in claim 1, wherein said first means converts any intercepted sonic wave into a wave signal and said coupling means sends this wave signal to said second means, and said second means responds to this wave signal from said first means for indicating that this wave signal has exceeded a predetermined level thereby detecting a leak of fluid from said pipe.

7. An apparatus as set forth in claim 1, further comprising a self-correlator for selectively identifying a sonic wave caused by a leak from among sonic waves intercepted by said first means by means of self-correlation analysis.

8. An apparatus as set forth in claim 1, further comprising a structure for enabling each of at least adjacent two of said first means to intercept a sonic wave caused by a leak occurring between said two first means and a cross-correlator for subjecting to cross-correlation analysis at least two sonic waves intercepted by a plurality of said first means respectively to identify selectively a sonic wave caused by a leak from among sonic waves thus intercepted.

9. An apparatus as set forth in claim 1, further comprising a unit for identifying leak-indicating sonic waves in the form of pattern changes over a period of time in frequency and intensity of any sonic wave intercepted by said first means, and a structure for comparing the pattern thus obtained with a standard pattern showing changes over a period of time in frequency and intensity of a sonic wave when a leak of fluid from said pipe is known to be present.

10. An apparatus as set forth in claim 1, wherein said first unit comprises a means for computing the ratio of the intensity of sonic waves intercepted by at least two of said first means.

11. An apparatus as set forth in claim 1, further comprising a self-correlator for subjecting each of the signals to self-correlation analysis before computing the ratio of the intensity to identify an intercepted signal caused by a leak from among intercepted signals.

12. An apparatus as set forth in claim 1, wherein said third means comprises a unit for comparing the difference in time required for a sonic wave caused by the leak to be propagated from a given leak point to at least two of said first means respectively by a cross-correlation analysis among the intercepted signals.

13. The apparatus as set forth in claim 1 further comprising:

at least one valve for stopping transport of fluid through said pipe, and means coupled to said third means and operable in response to an instruction signal from said third means for automatically closing said valve.