WO1994023242A1 - A device and a method for localizing leakages in conduit networks - Google Patents
A device and a method for localizing leakages in conduit networks Download PDFInfo
- Publication number
- WO1994023242A1 WO1994023242A1 PCT/SE1994/000283 SE9400283W WO9423242A1 WO 1994023242 A1 WO1994023242 A1 WO 1994023242A1 SE 9400283 W SE9400283 W SE 9400283W WO 9423242 A1 WO9423242 A1 WO 9423242A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- diaphragm
- sound
- frequency
- conduit
- liquid
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/24—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using infrasonic, sonic, or ultrasonic vibrations
- G01M3/243—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using infrasonic, sonic, or ultrasonic vibrations for pipes
Definitions
- the present invention relates to a device and to a method for localizing leakages in conduit networks, by listening for sound, even slight sound, generated by leaking liquid, particularly in pipe systems that are comprised of materi- als which have only low sound conductivity, such as plastic materials and the like.
- One method of minimizing these drawbacks is to have at one's disposal an effective and simple auxiliary device by means of which the distribution system can be checked with the intention of discovering a possible leakage as early as possible.
- the acoustic converters used in hydrophones are normally comprised of piezoelectric crystals having a high resonance frequency, e.g. a frequency of 100 kHz. This crystal can be combined with a mechanical element, such as a diaphragm, having a lower resonance frequency.
- the device taught by US-A 4,779,246 includes a diaphragm which has been tensioned in a way to provide the lowest resonance frequency.
- the object of the present invention is to eliminate the aforesaid disadvantages and drawbacks of devices for listening for leakage sounds in extensive pipe or conduit network systems.
- the best listening range will depend on direct contact between the listening element and the medium.
- hydrophones that are available commercially are normally constructed for general measuring purposes and therefore have a very wide frequency range and are not directly suited for leakage finding. These hydrophones are usually mounted in conduit networks so as to be sensitive or responsive to oscillations that are propagated in the pipe wall, meaning that traffic generated vibrations, for instance, will be fully detected.
- One known method of increasing the frequency of an acoustic signal is to record the sound on a tape recorder which operates at a low speed and then play back the sound at a higher speed.
- Another method is to record signals digitally with the aid of so-called sampling.
- the aforesaid problems are solved in accordance with the inventive concept by including in the device a first diaphragm whose one side is intended to be in contact with the liquid and which transmits oscillations from the liquid to a second diaphragm which is attached to that side of the first diaphragm which is out of contact with said liquid, wherein said second diaphragm is constructed of a piezo ⁇ electric material, preferably an acoustic-responsive, piezoelectric plastic sheet, wherein the first and the second diaphragms are able to oscillate together at frequencies of from zero to some thousand Hertz, wherein said first diaphragm is intended to withstand the internal pressure in the liquid-conducting conduit and to protect the sound-responsive diaphragm from direct contact with said liquid, and is also intended to attenuate any reso- nance oscillations that may occur, wherein the low-frequen ⁇ cy electric alternating current that is generated by the oscillations in the sound-responsive
- This construction renders the diaphragm insensitive to oscillations in the longitudinal direction of the conduit, i.e. directions which are parallel with the diaphragm surface, while enabling medium-carried sound that impinges transversely to the diaphragm surface to be discovered.
- a device which is highly responsive to leakage sound, i.e. will allow dynamic pressure oscillations to pass through but isolates static pressure, wherein the device is reliable in operation, for instance the possible presence of an air cushion between medium and diaphragm will not cause any appreciable attenuation of the acoustic signals, and a device which has low response to ground- carried disturbances and which can be applied easily to parts of the conduit network, and in which device the recorded sound signal is converted to a higher frequency that is audible to the human ear, by FFT-conversion, multiplication and inverse FFT-processing.
- Fig. 1 is a sectioned view of the invention
- Fig. 2 illustrates frequency curves for: B a piezoelectric crystal connected to a diaphragm with resonance; A a conventional piezoelectric crystal; and C shows the frequency curve for the present invention
- Fig. 3 illustrates frequency curves representative of the leakage sounds occurring in conduits, E in plastic conduits and D in iron conduits;
- Fig. 4 is a diagram illustrating a small section taken from the curve form of the original acoustic signal
- Fig. 5 illustrates sections that have been taken from the curve in Fig. 4 and recorded at elevated speeds
- Fig. 6 is a diagram illustrating an acoustic signal
- Fig. 7 illustrates the frequency spectrum of the acoustic signal shown in Fig. 6, according to FFT.
- Fig. 8 illustrates the newly converted acoustic signal of higher frequency.
- the inventive device includes a first circular diaphragm 1 which is made of thin stainless steel, for instance, and has a thickness of 0.05- 0.06 mm.
- the diaphragm is attached to a rigid holder 2, for instance welded or soldered thereto.
- the diaphragm includes a surface 3 which is intended to lie in contact with the water conducted by the conduit system and is able to withstand the pressure of 6-10 kg/cm 2 prevailing in the conduits.
- the diaphragm also has an inner surface 4 on which a second diaphragm 5 is firmly mounted.
- This second diaphragm is comprised of a piezoelectric plastic sheet which is flexible and accompanies the movements of the first diaphragm, therewith generating electric signals. These electric signals are passed through electric conduc ⁇ tors 6 to a device which analyzes the low frequency sound recorded and converts the frequency 7, whereafter the electric signals are sent to an amplifier 8 to which there is connected a pair of earphones 9.
- the holder 2 is constructed to enable it to be applied to a fire cock or fire hydrant 10, for instance, and is provided with a packing 3 for sealing the holder on the hydrant.
- the analyzing apparatus and the frequency converter 7 contain electronic circuits for transposing sound of low frequency to sound of higher frequency, so that the sound can be discerned by the human ear.
- the acoustic signals are sampled in accordance with sampling techniques and the acoustic signals are then compressed by excluding or shortening the interval between the sampling processes.
- the bandwidth is also transposed in addition to the frequencies, which means that the sound will have the same character as that normally emanating from iron conduits.
- Fig. 2 illustrates frequency curves for: B a piezoelectric crystal coupled to a diaphragm that has resonance; A a conventional piezoelectric crystal; and C illustrates the frequency curve obtained with the present invention. It is evident from the diagram that neither the curve A nor the curve B cover low frequencies, whereas the curve C has uniform sensitivity or responsiveness from zero frequency and upwards.
- Fig. 3 illustrates the frequency curves representative of the leakage sounds that occur in conduits, E in plastic conduits and D in iron conduits.
- Figs. 4 and 5 illustrate digital recording of a signal with the aid of sampling.
- Fig. 4 shows small sections taken from the curve form of the original acoustic signal
- Fig. 5 shows the sections taken from said curve form and played back at higher speeds.
- Fig. 6 illustrates a curve representative of an incoming low-frequency acoustic signal, which for the sake of clarity has been shown as sinusoidal but which in practice can have any form.
- Fig. 7 illustrates a typical sound spectrum for a curve according to Fig. 6, and shows how the same spectrum can be moved to a higher frequency range by multiplication.
- Fig. 8 illustrates the newly converted acoustic signal of the higher frequency, which corresponds to the spectrum in Fig. 7 moved to a higher frequency.
- the device components can be assembled and joined by welding, gluing or corresponding processes.
- the frequency can be transposed by recording the signals digitally, with the aid of sampling.
- the inventive device can also be used as an acoustic transmitter when an electric voltage is applied to the piezoelectric diaphragm.
- This diaphragm will then function as a sound transmitter and can be used in searching for buried plastic conduits whose position are not completely known.
Abstract
Description
Claims
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002159362A CA2159362C (en) | 1993-03-29 | 1994-03-29 | A device and a method for localizing leakages in conduit networks |
DE69410607T DE69410607T2 (en) | 1993-03-29 | 1994-03-29 | DEVICE AND METHOD FOR LOCALIZING LEAKS IN CABLE NETWORKS |
AU64400/94A AU6440094A (en) | 1993-03-29 | 1994-03-29 | A device and a method for localizing leakages in conduit networks |
DK94912124T DK0694145T3 (en) | 1993-03-29 | 1994-03-29 | Device and method for locating leaks in pipeline networks |
JP52143994A JP3295087B2 (en) | 1993-03-29 | 1994-03-29 | Apparatus and method for locating leaks in a conduit network |
EP94912124A EP0694145B1 (en) | 1993-03-29 | 1994-03-29 | A device and a method for localizing leakages in conduit networks |
US08/530,207 US5639958A (en) | 1993-03-29 | 1994-03-29 | Device and a method for localizing leakages in conduit networks |
NO952592A NO304758B1 (en) | 1993-03-29 | 1995-09-26 | Device and method for locating leaks in wiring harness |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9301020A SE506195C2 (en) | 1993-03-29 | 1993-03-29 | Hydrophone system for monitoring wiring networks |
SE9301020-5 | 1993-03-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1994023242A1 true WO1994023242A1 (en) | 1994-10-13 |
Family
ID=20389381
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1994/000283 WO1994023242A1 (en) | 1993-03-29 | 1994-03-29 | A device and a method for localizing leakages in conduit networks |
Country Status (11)
Country | Link |
---|---|
US (1) | US5639958A (en) |
EP (1) | EP0694145B1 (en) |
JP (1) | JP3295087B2 (en) |
AT (1) | ATE166709T1 (en) |
AU (1) | AU6440094A (en) |
CA (1) | CA2159362C (en) |
DE (1) | DE69410607T2 (en) |
DK (1) | DK0694145T3 (en) |
NO (1) | NO304758B1 (en) |
SE (1) | SE506195C2 (en) |
WO (1) | WO1994023242A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102008062291B3 (en) * | 2008-12-15 | 2010-07-22 | Abb Technology Ag | Measuring device and method for the diagnosis of noise in fluidic systems |
EP2899526A4 (en) * | 2012-09-24 | 2016-06-15 | Sekisui Chemical Co Ltd | Leakage detector, leakage detection method, and pipe network monitoring apparatus |
Families Citing this family (18)
Publication number | Priority date | Publication date | Assignee | Title |
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GB2337117B (en) | 1998-05-04 | 2001-04-04 | Csi Technology Inc | Digital ultrasonic monitoring system and method |
CH703142B1 (en) † | 1999-05-10 | 2011-11-30 | Vonroll Infratec Invest Ag | Leak detector system. |
DE102005048726B4 (en) * | 2005-10-12 | 2010-09-16 | Airbus Deutschland Gmbh | leak |
US7210337B1 (en) * | 2005-10-17 | 2007-05-01 | Honeywell International Inc. | MEMS sensor package leak test |
EP2582886B1 (en) | 2010-06-16 | 2019-11-27 | Mueller International, LLC | Infrastructure monitoring devices, systems, and methods |
US9593999B2 (en) | 2011-08-12 | 2017-03-14 | Mueller International, Llc | Enclosure for leak detector |
WO2014066764A1 (en) | 2012-10-26 | 2014-05-01 | Mueller International, Llc | Detecting leaks in a fluid distribution system |
US9528903B2 (en) | 2014-10-01 | 2016-12-27 | Mueller International, Llc | Piezoelectric vibration sensor for fluid leak detection |
CN105889763B (en) * | 2014-10-10 | 2017-12-15 | 保定市金迪科技开发有限公司 | The detection device and its detection method of a kind of pipe leakage |
US10283857B2 (en) | 2016-02-12 | 2019-05-07 | Mueller International, Llc | Nozzle cap multi-band antenna assembly |
US10305178B2 (en) | 2016-02-12 | 2019-05-28 | Mueller International, Llc | Nozzle cap multi-band antenna assembly |
WO2019236897A1 (en) | 2018-06-08 | 2019-12-12 | Orbis Intelligent Systems, Inc. | Pipe sensors |
US11733115B2 (en) | 2018-06-08 | 2023-08-22 | Orbis Intelligent Systems, Inc. | Detection devices for determining one or more pipe conditions via at least one acoustic sensor and including connection features to connect with an insert |
US11698314B2 (en) | 2018-06-08 | 2023-07-11 | Orbis Intelligent Systems, Inc. | Detection device for a fluid conduit or fluid dispensing device |
US10859462B2 (en) | 2018-09-04 | 2020-12-08 | Mueller International, Llc | Hydrant cap leak detector with oriented sensor |
US11342656B2 (en) | 2018-12-28 | 2022-05-24 | Mueller International, Llc | Nozzle cap encapsulated antenna system |
US11473993B2 (en) | 2019-05-31 | 2022-10-18 | Mueller International, Llc | Hydrant nozzle cap |
US11542690B2 (en) | 2020-05-14 | 2023-01-03 | Mueller International, Llc | Hydrant nozzle cap adapter |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US2008934A (en) * | 1933-04-11 | 1935-07-23 | Alonzo L Smith | Leak detector for pipe lines |
US4435974A (en) * | 1980-12-04 | 1984-03-13 | Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. | Method and apparatus for locating leakages in pipes and similar conduits |
US4779246A (en) * | 1986-03-20 | 1988-10-18 | Siemens Aktiengesellschaft | Electro-acoustic transducer |
US4810913A (en) * | 1986-08-27 | 1989-03-07 | Institut Francais Du Petrole | Increased sensitivity piezoelectric hydrophones |
US5101774A (en) * | 1989-08-03 | 1992-04-07 | Westvaco Corporation | Acoustic leak detection system |
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US3596510A (en) * | 1970-02-04 | 1971-08-03 | Nasa | Resonant infrasonic gauging apparatus |
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JPS55131741A (en) * | 1979-04-02 | 1980-10-13 | Osaka Gas Co Ltd | Method of detecting leakage of gas |
US4309576A (en) * | 1979-07-16 | 1982-01-05 | Heath Consultants Incorporated | Listening device for localizing underground water leakages |
JPS58168934A (en) * | 1982-03-31 | 1983-10-05 | Hitachi Ltd | Method and device for detecting leakage of liquid |
US4498333A (en) * | 1983-06-01 | 1985-02-12 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Carbon granule probe microphone for leak detection |
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JPS6472025A (en) * | 1987-09-14 | 1989-03-16 | Nippon Atomic Ind Group Co | Vapor leak monitoring device |
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JP2602955B2 (en) * | 1989-07-05 | 1997-04-23 | 株式会社東芝 | Valve and pipe leak cause determination method and device |
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JPH03100430A (en) * | 1989-09-14 | 1991-04-25 | Nippon Enjiniyaa Service Kk | Leakage inspecting device for tank |
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1993
- 1993-03-29 SE SE9301020A patent/SE506195C2/en not_active IP Right Cessation
-
1994
- 1994-03-29 DE DE69410607T patent/DE69410607T2/en not_active Expired - Fee Related
- 1994-03-29 AT AT94912124T patent/ATE166709T1/en not_active IP Right Cessation
- 1994-03-29 JP JP52143994A patent/JP3295087B2/en not_active Expired - Fee Related
- 1994-03-29 CA CA002159362A patent/CA2159362C/en not_active Expired - Fee Related
- 1994-03-29 EP EP94912124A patent/EP0694145B1/en not_active Expired - Lifetime
- 1994-03-29 US US08/530,207 patent/US5639958A/en not_active Expired - Lifetime
- 1994-03-29 AU AU64400/94A patent/AU6440094A/en not_active Abandoned
- 1994-03-29 WO PCT/SE1994/000283 patent/WO1994023242A1/en active IP Right Grant
- 1994-03-29 DK DK94912124T patent/DK0694145T3/en active
-
1995
- 1995-09-26 NO NO952592A patent/NO304758B1/en unknown
Patent Citations (5)
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US2008934A (en) * | 1933-04-11 | 1935-07-23 | Alonzo L Smith | Leak detector for pipe lines |
US4435974A (en) * | 1980-12-04 | 1984-03-13 | Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. | Method and apparatus for locating leakages in pipes and similar conduits |
US4779246A (en) * | 1986-03-20 | 1988-10-18 | Siemens Aktiengesellschaft | Electro-acoustic transducer |
US4810913A (en) * | 1986-08-27 | 1989-03-07 | Institut Francais Du Petrole | Increased sensitivity piezoelectric hydrophones |
US5101774A (en) * | 1989-08-03 | 1992-04-07 | Westvaco Corporation | Acoustic leak detection system |
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Title |
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DERWENT'S ABSTRACT, No. 89-148814/20, week 8920; & SU,A,1413354 (INTROSCOPY RES INST), 30 July 1988 (30.07.88), the whole document. * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102008062291B3 (en) * | 2008-12-15 | 2010-07-22 | Abb Technology Ag | Measuring device and method for the diagnosis of noise in fluidic systems |
US8220333B2 (en) | 2008-12-15 | 2012-07-17 | Abb Technology Ag | Measurement device and method for diagnosis of noise in fluidic systems |
EP2899526A4 (en) * | 2012-09-24 | 2016-06-15 | Sekisui Chemical Co Ltd | Leakage detector, leakage detection method, and pipe network monitoring apparatus |
AU2013318975B2 (en) * | 2012-09-24 | 2017-02-02 | Sekisui Chemical Co., Ltd. | Leakage detector, leakage detection method, and pipe network monitoring apparatus |
US10168243B2 (en) | 2012-09-24 | 2019-01-01 | Sekisui Chemical Co., Ltd. | Leakage detector, leakage detection method, and pipe network monitoring apparatus |
Also Published As
Publication number | Publication date |
---|---|
ATE166709T1 (en) | 1998-06-15 |
EP0694145A1 (en) | 1996-01-31 |
SE9301020L (en) | 1994-09-30 |
NO304758B1 (en) | 1999-02-08 |
DE69410607D1 (en) | 1998-07-02 |
SE9301020D0 (en) | 1993-03-29 |
US5639958A (en) | 1997-06-17 |
DK0694145T3 (en) | 1999-03-22 |
CA2159362C (en) | 2005-08-02 |
JPH08508808A (en) | 1996-09-17 |
DE69410607T2 (en) | 1999-01-07 |
JP3295087B2 (en) | 2002-06-24 |
SE506195C2 (en) | 1997-11-17 |
AU6440094A (en) | 1994-10-24 |
CA2159362A1 (en) | 1994-10-13 |
NO953800D0 (en) | 1995-09-26 |
NO953800L (en) | 1995-09-26 |
EP0694145B1 (en) | 1998-05-27 |
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