GB2235294A - Improvements in acoustic tomography - Google Patents

Improvements in acoustic tomography Download PDF

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Publication number
GB2235294A
GB2235294A GB9016718A GB9016718A GB2235294A GB 2235294 A GB2235294 A GB 2235294A GB 9016718 A GB9016718 A GB 9016718A GB 9016718 A GB9016718 A GB 9016718A GB 2235294 A GB2235294 A GB 2235294A
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United Kingdom
Prior art keywords
area
transducers
interest
array
acoustic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9016718A
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GB2235294B (en
GB9016718D0 (en
Inventor
Peter Olley
Iain Donald Macleod
Malcolm John Beesley
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UK Atomic Energy Authority
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UK Atomic Energy Authority
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Publication date
Application filed by UK Atomic Energy Authority filed Critical UK Atomic Energy Authority
Publication of GB9016718D0 publication Critical patent/GB9016718D0/en
Publication of GB2235294A publication Critical patent/GB2235294A/en
Application granted granted Critical
Publication of GB2235294B publication Critical patent/GB2235294B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • G01N29/024—Analysing fluids by measuring propagation velocity or propagation time of acoustic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H3/00—Measuring characteristics of vibrations by using a detector in a fluid
    • G01H3/10—Amplitude; Power
    • G01H3/12—Amplitude; Power by electric means
    • G01H3/125—Amplitude; Power by electric means for representing acoustic field distribution
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
    • G01K11/22—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using measurement of acoustic effects
    • G01K11/24—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using measurement of acoustic effects of the velocity of propagation of sound
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • G01N29/032—Analysing fluids by measuring attenuation of acoustic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/028—Material parameters
    • G01N2291/02881—Temperature

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Analytical Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Engineering & Computer Science (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

An array of acoustic transducers T1-T8 is arranged around an area 10 of interest e.g. in a water tank 12 and each transducer, in turn, transmits pulses of sound signals which are received by each of the other transducers. The area is notionally sub-divided into a square grid cell being traversed by at least one sound path between transducers. The acoustic characteristics can be determined for each cell and used to measure temperature and/or to detect gas bubbles in a fluid from sound propagation velocity and attenuation. <IMAGE>

Description

Improvements in Acoustic Tomography The present invention concerns acoustic tomography whereby conditions within a plane area of a medium can be monitored by noting variations in the acoustic transmission properties over the area.
According to the present invention a method of acoustic tomography comprises arranging an array of acoustic transducers around a plane area of interest, actuating each transducer in the array in sequence to transmit pulses of high frequency signals, receiving the transmitted signals at each of the other transducers in the array and utilising the signals to determine particular properties within the area of interest.
Acoustic tomography can be used to monitor conditions within a plane area of a fluid by measuring variations in acoustic transmission properties over the area. The method can monitor an effect which produces an associated detectable change in acoustic properties, for example, the temperature distribution by the variation in acoustic velocity or the gas bubble content in a liquid by the variation in acoustic attenuation.
The invention will be described further, by way of example, with reference to the accompanying diagram which depicts positions of transducers and cell divisions at an area of scanning.
An array of eight acoustic transducers T1 to T8 inclusive is positioned around an area of interest. For example the transducers are arranged in a square array 10 in a water tank 12. The array is sub-divided into cells ij, the number of cells being determined by the required spatial resolution. In the present example the array is sub-divided into a 5 x 5 grid of 25 cells. A pulse of high frequency sound from each transducer will pass through a number of cells and its velocity and attenuation will be a combination of the velocities and attenuations encountered in each of the cells.
The arrangement is to transmit a sufficient number of sound pulses across the array in different directions to traverse each cell ij and obtain sufficient data to permit the assembly of a set of simultaneous equations from which the velocity and attenuation in each cell can be determined.
Each transducer T1 to T8 is actuated in turn to emit a burst of sound which is detected at the other seven transducers. The sound transmissions can be measured along a total of 8 x 7 = 56 paths but as there are two directions of travel between any given pair of transducers the number of distinct paths is 56/2 = 28.
In tomography, the number of distinct paths between transducers must not be less than the number of cells in the array for the solution of the set of simultaneous equations.
In use, a burst of sound is transmitted by T1 and the signal received at the other transducers is recorded in digital form and stored. The procedure is repeated for each of T2 to T8 in turn until signals transmitted along each of the 28 paths have been stored.
The stored signals are processed to extract transit times or transmission signal strengths along each path.
These values can then be used to calculate temperature or attenuation in each cell ij.
The array of eight transducers monitoring the 5 x 5 grid shown in the diagram was used to assess the technique in water at room temperature. The array detected and located the presence of injected streams of hot water and gas bubbles as they passed through the monitored area.
The method can be employed for scanning a hostile environment from a remote location. For example, it can be used for scanning the area above the core of a nuclear reactor. In such a case the array can be divided into cells which correspond to the lattice arrangement of the reactor core. The technique is applicable to most fluids and can be used in water cooled or sodium cooled reactors for example. The velocity of sound measurement can be used to deduce temperature, since velocity of sound in fluids is a function of temperature. Similarly, attenuation can be used to indicate changes in the gas content of the fluid, such as the presence of bubbles in the fluid.

Claims (5)

Claims
1. A method of acoustic tomography which comprises arranging an array of acoustic transducers around a plane area of interest, actuating each transducer in the array in sequence to transmit pulses of high frequency sound signals, receiving the transmitted signals at each of the other transducers in the array and utilising the signals to determine particular properties within the area of interest.
2. A method as claimed in claim 1 which comprises utilising the signals to deduce temperature changes and/or changes in gas content within the area of interest.
3. A method as claimed in claim 1 or 2 which comprises notionally dividing the area of interest into a grid of cells whereby each cells is traversed by at least one sound path between transducers.
4. A method as claimed in claim 3 which comprises establishing the area of interest as a plane above the core of a nuclear reactor and arranging the grid to correspond to the lattice configuration of the reactor core.
5. A method of acoustic tomography substantially as herein described with reference to the accompanying drawing.
GB9016718A 1989-08-23 1990-07-30 Improvements in acoustic tomography Expired - Fee Related GB2235294B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB898919256A GB8919256D0 (en) 1989-08-23 1989-08-23 Improvements in acoustic tomography

Publications (3)

Publication Number Publication Date
GB9016718D0 GB9016718D0 (en) 1990-09-12
GB2235294A true GB2235294A (en) 1991-02-27
GB2235294B GB2235294B (en) 1993-12-22

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Family Applications (2)

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GB898919256A Pending GB8919256D0 (en) 1989-08-23 1989-08-23 Improvements in acoustic tomography
GB9016718A Expired - Fee Related GB2235294B (en) 1989-08-23 1990-07-30 Improvements in acoustic tomography

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB898919256A Pending GB8919256D0 (en) 1989-08-23 1989-08-23 Improvements in acoustic tomography

Country Status (1)

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GB (2) GB8919256D0 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5531116A (en) * 1994-01-12 1996-07-02 Hughes Aircraft Company Apparatus and method for phase tomographic determination of fluid currents
DE10051506C2 (en) * 1999-10-21 2003-12-11 Korea Advanced Inst Sci & Tech Process for the optimal determination of sensor positions for sound pyrometry

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1523231A (en) * 1976-02-18 1978-08-31 Redding R J Gas detection
GB2139352A (en) * 1983-05-04 1984-11-07 Central Electr Generat Board Fluid temperature and velocity measuring arrangement
EP0152874A1 (en) * 1984-02-07 1985-08-28 TERUMO KABUSHIKI KAISHA trading as TERUMO CORPORATION Ultrasonic measurement method, and apparatus therefor
GB2153999A (en) * 1984-02-03 1985-08-29 Atomic Energy Authority Uk Remote temperature measurement
US4700571A (en) * 1985-06-19 1987-10-20 Kabushiki Kaisha Toshiba Ultrasonic imaging apparatus
EP0256686A1 (en) * 1986-07-22 1988-02-24 Kabushiki Kaisha Toshiba Method and apparatus for measuring ultrasonic velocity in a medium by crossed beams
GB2207755A (en) * 1987-08-06 1989-02-08 Atomic Energy Authority Uk Temperature measurement in a fluid by means of reflected stress waves
GB2217457A (en) * 1988-04-05 1989-10-25 Nittan Co Ltd A multi-channel ultrasonic fire monitoring system

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1050654A (en) * 1974-04-25 1979-03-13 Varian Associates Reconstruction system and method for ultrasonic imaging
US4105018A (en) * 1976-02-02 1978-08-08 University Of Utah Acoustic examination, material characterization and imaging of the internal structure of a body by measurement of the time-of-flight of acoustic energy therethrough
FR2429436A1 (en) * 1978-06-20 1980-01-18 Anvar IMPROVEMENTS IN METHODS AND DEVICES FOR ULTRASONIC TRANSVERSE TOMOGRAPHY BY RECONSTRUCTION

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1523231A (en) * 1976-02-18 1978-08-31 Redding R J Gas detection
GB2139352A (en) * 1983-05-04 1984-11-07 Central Electr Generat Board Fluid temperature and velocity measuring arrangement
EP0125061A1 (en) * 1983-05-04 1984-11-14 Central Electricity Generating Board Fluid temperature and velocity measuring arrangement
GB2153999A (en) * 1984-02-03 1985-08-29 Atomic Energy Authority Uk Remote temperature measurement
EP0152874A1 (en) * 1984-02-07 1985-08-28 TERUMO KABUSHIKI KAISHA trading as TERUMO CORPORATION Ultrasonic measurement method, and apparatus therefor
US4700571A (en) * 1985-06-19 1987-10-20 Kabushiki Kaisha Toshiba Ultrasonic imaging apparatus
EP0256686A1 (en) * 1986-07-22 1988-02-24 Kabushiki Kaisha Toshiba Method and apparatus for measuring ultrasonic velocity in a medium by crossed beams
US4821574A (en) * 1986-07-22 1989-04-18 Kabushiki Kaisha Toshiba Method and apparatus for measuring ultrasonic velocity by crossed beam
GB2207755A (en) * 1987-08-06 1989-02-08 Atomic Energy Authority Uk Temperature measurement in a fluid by means of reflected stress waves
GB2217457A (en) * 1988-04-05 1989-10-25 Nittan Co Ltd A multi-channel ultrasonic fire monitoring system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5531116A (en) * 1994-01-12 1996-07-02 Hughes Aircraft Company Apparatus and method for phase tomographic determination of fluid currents
DE10051506C2 (en) * 1999-10-21 2003-12-11 Korea Advanced Inst Sci & Tech Process for the optimal determination of sensor positions for sound pyrometry

Also Published As

Publication number Publication date
GB2235294B (en) 1993-12-22
GB9016718D0 (en) 1990-09-12
GB8919256D0 (en) 1989-10-11

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 19950730