CA1094677A - Acoustic emission transducer and system - Google Patents
Acoustic emission transducer and systemInfo
- Publication number
- CA1094677A CA1094677A CA250,548A CA250548A CA1094677A CA 1094677 A CA1094677 A CA 1094677A CA 250548 A CA250548 A CA 250548A CA 1094677 A CA1094677 A CA 1094677A
- Authority
- CA
- Canada
- Prior art keywords
- housing
- transducer
- wearplate
- acoustic
- crystal
- 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.)
- Expired
Links
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
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/24—Probes
-
- 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
- G01N29/14—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 using acoustic emission techniques
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/18—Methods or devices for transmitting, conducting or directing sound
- G10K11/26—Sound-focusing or directing, e.g. scanning
- G10K11/30—Sound-focusing or directing, e.g. scanning using refraction, e.g. acoustic lenses
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C17/00—Monitoring; Testing ; Maintaining
- G21C17/003—Remote inspection of vessels, e.g. pressure vessels
- G21C17/007—Inspection of the outer surfaces of vessels
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Pathology (AREA)
- Acoustics & Sound (AREA)
- Immunology (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Multimedia (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Acoustic signals emitted by systems under pressure or stress are detected by acoustic sensors placed on the structure and the detected acoustic emissions are processed and analyzed to determine the presence of any defects in the structure, their location and significance. The sensor comprises a relatively small diameter transducer which can be bonded at appropriate locations on the surface of the system being tested.
After being used, the transducers can be removed and reused again. Each transducer comprises a machined metal casing which includes a combined lens wearplate which is unitary, that is integral, with the casing and a detecting element such as a piezoelectric crystal bonded to the inner surface of the lens wearplate.
Acoustic signals emitted by systems under pressure or stress are detected by acoustic sensors placed on the structure and the detected acoustic emissions are processed and analyzed to determine the presence of any defects in the structure, their location and significance. The sensor comprises a relatively small diameter transducer which can be bonded at appropriate locations on the surface of the system being tested.
After being used, the transducers can be removed and reused again. Each transducer comprises a machined metal casing which includes a combined lens wearplate which is unitary, that is integral, with the casing and a detecting element such as a piezoelectric crystal bonded to the inner surface of the lens wearplate.
Description
lO~fi77 BAC~GROUND OF ~IE INVENTION
In connection with the testing of pressure vessels and other pressure s~stems under stress, various nondestruc-tive test techniques such as ultrasonics are radiography havre been used. These procedures generally involve laborious search and find procedure and oftentimes removal or disassembly of system components. The integrity of pressurized systems, especially those which are volatile, is of natural concern to many people. A failure on any part of such a system can result in costly downtime and personnel hazards. It is clear then that knowledge of the structural integrity of pressure systems is of prime concern and importance, and that there is a need for a system which can provide integrity analysis of a structure quickly, a response which is indicative of structural significance, requires limited access, and does not require interruption of processing operations.
In connection with such a stress analysis system, there exists a need to satisfactorily mount the transducers to the particular vessel being tested. The mountings should permit the transducer to be bonded to the structure surface without the danger of the transducer's wearplate separating therefrom when the transducer is removed from the vessel.
Further, upon removal of the transducer no damage should occur to it so that it can be used again.
Among the prior art references located during a prior art search for the isubject invention as relates to the transducer are the following patents:
U. S. 2,888,581 - Pahud U. S. 3,292,910 - Martner U. S. 3,390,286 - Gradin et al U. S. 3,427,481 - Lenahan et al
In connection with the testing of pressure vessels and other pressure s~stems under stress, various nondestruc-tive test techniques such as ultrasonics are radiography havre been used. These procedures generally involve laborious search and find procedure and oftentimes removal or disassembly of system components. The integrity of pressurized systems, especially those which are volatile, is of natural concern to many people. A failure on any part of such a system can result in costly downtime and personnel hazards. It is clear then that knowledge of the structural integrity of pressure systems is of prime concern and importance, and that there is a need for a system which can provide integrity analysis of a structure quickly, a response which is indicative of structural significance, requires limited access, and does not require interruption of processing operations.
In connection with such a stress analysis system, there exists a need to satisfactorily mount the transducers to the particular vessel being tested. The mountings should permit the transducer to be bonded to the structure surface without the danger of the transducer's wearplate separating therefrom when the transducer is removed from the vessel.
Further, upon removal of the transducer no damage should occur to it so that it can be used again.
Among the prior art references located during a prior art search for the isubject invention as relates to the transducer are the following patents:
U. S. 2,888,581 - Pahud U. S. 3,292,910 - Martner U. S. 3,390,286 - Gradin et al U. S. 3,427,481 - Lenahan et al
- 2 -~0'3'~7~
U. S. 3,56~,163 - Fischer et al U. S. 3,612,921 - Springate U. S. 3,703,652 - Noda U. S. 3,735,159 - Murry U. S. 3,769,532 - Tocquet et al U. S. 3,794,866 - McElroy et al SUMMA~Y_OF THE INVENTION
According to the present ,invention, there is pro-vided a tool which can investigate the structural integrity of pressure vessels and related systems, including structures such as reactor vessels, heat exchangers, high pressure separators, piping and nuclear power plant coolant systems.
With essentially no interruption to operation, transducers and related equipment are properly positioned to receive acoustic signals emitted by the systems under pressure or stress, which when properly analyzed will produce an acoustic energy release pattern that will show possible significant defect growth and also provide immediate warning of signi-ficant defects in the system. A computer map which re-presents a geometrically accurate layout of the systemundergoing analysis can be provided in order to analyze severity and precise location of a defect, More particularly the emitted acoustic signals are detected by sensitive acoustic sensors or transducers appro-priately located on the structural surfaces. These signals are generated by discontinuities in the stressed material being analyzed, The detected emissions or signals are ampli-fied and then transmitted through cables to a remotely-located unit at which signal conditioning, processing and analysis takes place. The number of transducers employed and their placement on the structural surface will depend ~.0~ ;7~7 upon the type and conf:iguration of the system to be analyzed.
Also in accordance with the present invention, the electroacoustic transducer employed comprises a relatively small diameter transducer which is reusable, that is, it can be bonded to a structural surface, used to detect acoustic emissions, disbonded after use and then reused. Such trans-ducer comprises a combined lens wearplate which is integral with, that is a unitary portion of, the machined metal casing of the transducer. The detecting element comprises a piezo-electric crystal which is located internally of the casingand is bonded to an inner surface of the lens wearplate.
In accordance with a specific embodiment, an acoustic emission transducer comprises a crystal detector element for sensing acoustic emissions, a cylindrical metal housing for said crystal detector element, said housing having a main axis and comprising a bottom wearplate end integral with said housing and an opposite open end, said bottom end including a lens portion integral with said wear-plate and located internally of said housing and comprising tapered sides having a slope inward toward said main axis extending from said wearplate toward said open end for con-centrating energy received from the sensed emissions onto said crystal detector element and terminating in a planar surface at a fixed distance from said wearplate end axially spaced therefrom, and means securing said crystal detector element to said planar surface.
In accordance with a further aspect of the inven-tion, a system for use in detecting acoustic signals emitted from a pressure system under stress comprises in combination:
a structural surface under stress and having a plurality of acoustic transducer members mounted in predetermined spaced :10{~ ~i77 relation on said surface for mol~itor.i.ng the amount of energy per unit stress being released from said system, means for mounting a first end of said transducers to said surface such that the acoustic signals indicative of the system stress are coupled to said acoustic transducer members, each of said transducer members comprising a cylindrical metal housing having a main axis and comprising a bottom wearplate end integral with said housing and a crystal element mounted therein for sensing said acoustic signals coupled through said housing, a frustoconically-shaped lens portion integral with said wearplate and said housing and located internally of said housing adjacent said first end thereof mounted to said surface and having tapered side walls which slope inwardly from said first end toward said main axis extending in the direction from said first end toward a second open end of said housing opposite said first end, said side walls terminating in an internal element mounting platform surface axially spaced from said first end, said crystal element secured to said platform surface, the tapered configuration of said lens portion concentrat-ing energy received from said acoustic signals onto said crystal element.
The features of the present invention will be explained in further detail with reference to the drawings described below.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side elevation view of the transducer casing or housing in accordance with the present invention' Figure 2 is a side elevation view of the combination of the transducer casing or housing of Figure 1, together with the crystal detecting element and its cable connections; and iO~ '7 Figure 3 lllustrates a typical service application for acoustic emission transducers constructed and arranged in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to Fig. 1, there is shown a machined metal housing or casing generally designated 10, which com-prises a cylindrically shaped body 12 having formed in a wall thereof at its upper end an opening in which is secured a cable inlet channel 14. The channel 14 comprises a tubular member disposed substantially perpendicular to the wall of cylindrical body 12, including an opening 16 for receiving the signal cable 18 (See Fig. 2) therein, and may be secured in place by welding or other suitable fastening means, or integrally formed with the housing. The adjacent or top end of the housing is open and has formed therewith an annular shelf or ledge`20 for seating a circular lid 22 which can be sealed in place by suitable means such as an epoxy cement to the housing once the crystal detecting ele-ment 24 is located therein as described hereinafter. At the bottom or affixing end of the transducer housing there is provided a portion comprising an integral wearplate 26 ~nd a lens 28. The wearplate essentially comprises the bottom or mounting surface of the transducer which permits it to be bonded to the structural surface of the pressure vessel or other structure under anal~sis for structural integrity. Located at the bottom or same end as the wear-plate is the lens 28 which is integral with the wearplate and comprises a truncated conical configuration. m e sides 30 of the lens extend upw~rd toward the open end sloping from the wearplate end of the housing radially inward, ~.0~ 77 preerably at an angle of about 45 with the vertical ax.is and walls of the housing. As best shown in Fig, 2, the crystal detecting element 24 is bonded at 32 to the upper or platform surface 34 of the lens by a suitable epoxy cement. The tapered configuration of the lens 28 from the wearplate in the direction toward - 6a -iO~,77 the open end or crystal serves to concentrate energy received from acoustic emission signals onto the crystal detecting element. The element typically may comprise a piezoelectric crystal which is connected through electrical connections 36 to the signal cable 18 which extends through the opening 16 into the interior of the housing. After the connections between the crystal detecting element and the signal cable are made, the lens cover or lid 22 is secured in place on the ledge 20 at the open end of the housing. One suitable material for the casing is stainless steel.
As shown in Fig. 2, the cable is secured in place in the cable inlet by means of a standard shring tubing seal generally designated 38. The signal cable extends through the seal and is connected as ~i~cussed hereinafter. Fig. 3 illustrates a typical location of the acoustic emission trans-ducers 10 constructed in accordance with the teachings of the present invention, secured to the surface 40 of a structure 42 under stress, usually at operating pressure or above, e.g., a pressure vessel. The transducers are placed at appropriate locations which correspond to pertinent physical features of the structure. For most pressure vessels ordinarily twelve to sixteen transducers should be sufficient, and less (four to six) for less complex structures. The transducers normally are situated along the length and circumferentially about the surface of the structure in order to detect acoustic emissions generated by the material under stress within the structure. The transducers are positioned on the structural surfaces and held in position with a magnetic mount or epoxy or tape. The installation may be temporary for duration of the test anl~ the transducers removed follow-ing analysis, or premanent if desired for frequent or 1ill~`1677 continuous analysis of the structure. The pieeoelectric element mounted on the inner or platform surface of the wearplate-lens detects the acoustic emission sounds which travel through the structure material and are coupled through the mounting to the transducer. Each transducer has a low noise, high gain amplifier 44 (per se conventional) which boosts or amplifies detected signals. These amplified signals are in turn transmitted via signal cabling 46 to a unit 48 where signal conditioning, processing and analysis takes place. Typically this may include monitoring of the amount of acoustic energy per unit stress being released from the structure and computer subsystems for determining significance and location of a defect. This may be done by placing an acetate overlay bearing scaled outline drawings of the system components under analysis over the computer display -to pinpoint precise locations of defects such as discontinuities.
While a preferred embodiment of the present invention has been shown, various modifications and variations in the construction and/or arrangement of the invention may present themselves to those skilled in the art upon a reading of this disclosure. It is intended that such variations and/or modifications fall within the scope of the present inven-tion which is better defined by reference to the appended claims.
U. S. 3,56~,163 - Fischer et al U. S. 3,612,921 - Springate U. S. 3,703,652 - Noda U. S. 3,735,159 - Murry U. S. 3,769,532 - Tocquet et al U. S. 3,794,866 - McElroy et al SUMMA~Y_OF THE INVENTION
According to the present ,invention, there is pro-vided a tool which can investigate the structural integrity of pressure vessels and related systems, including structures such as reactor vessels, heat exchangers, high pressure separators, piping and nuclear power plant coolant systems.
With essentially no interruption to operation, transducers and related equipment are properly positioned to receive acoustic signals emitted by the systems under pressure or stress, which when properly analyzed will produce an acoustic energy release pattern that will show possible significant defect growth and also provide immediate warning of signi-ficant defects in the system. A computer map which re-presents a geometrically accurate layout of the systemundergoing analysis can be provided in order to analyze severity and precise location of a defect, More particularly the emitted acoustic signals are detected by sensitive acoustic sensors or transducers appro-priately located on the structural surfaces. These signals are generated by discontinuities in the stressed material being analyzed, The detected emissions or signals are ampli-fied and then transmitted through cables to a remotely-located unit at which signal conditioning, processing and analysis takes place. The number of transducers employed and their placement on the structural surface will depend ~.0~ ;7~7 upon the type and conf:iguration of the system to be analyzed.
Also in accordance with the present invention, the electroacoustic transducer employed comprises a relatively small diameter transducer which is reusable, that is, it can be bonded to a structural surface, used to detect acoustic emissions, disbonded after use and then reused. Such trans-ducer comprises a combined lens wearplate which is integral with, that is a unitary portion of, the machined metal casing of the transducer. The detecting element comprises a piezo-electric crystal which is located internally of the casingand is bonded to an inner surface of the lens wearplate.
In accordance with a specific embodiment, an acoustic emission transducer comprises a crystal detector element for sensing acoustic emissions, a cylindrical metal housing for said crystal detector element, said housing having a main axis and comprising a bottom wearplate end integral with said housing and an opposite open end, said bottom end including a lens portion integral with said wear-plate and located internally of said housing and comprising tapered sides having a slope inward toward said main axis extending from said wearplate toward said open end for con-centrating energy received from the sensed emissions onto said crystal detector element and terminating in a planar surface at a fixed distance from said wearplate end axially spaced therefrom, and means securing said crystal detector element to said planar surface.
In accordance with a further aspect of the inven-tion, a system for use in detecting acoustic signals emitted from a pressure system under stress comprises in combination:
a structural surface under stress and having a plurality of acoustic transducer members mounted in predetermined spaced :10{~ ~i77 relation on said surface for mol~itor.i.ng the amount of energy per unit stress being released from said system, means for mounting a first end of said transducers to said surface such that the acoustic signals indicative of the system stress are coupled to said acoustic transducer members, each of said transducer members comprising a cylindrical metal housing having a main axis and comprising a bottom wearplate end integral with said housing and a crystal element mounted therein for sensing said acoustic signals coupled through said housing, a frustoconically-shaped lens portion integral with said wearplate and said housing and located internally of said housing adjacent said first end thereof mounted to said surface and having tapered side walls which slope inwardly from said first end toward said main axis extending in the direction from said first end toward a second open end of said housing opposite said first end, said side walls terminating in an internal element mounting platform surface axially spaced from said first end, said crystal element secured to said platform surface, the tapered configuration of said lens portion concentrat-ing energy received from said acoustic signals onto said crystal element.
The features of the present invention will be explained in further detail with reference to the drawings described below.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side elevation view of the transducer casing or housing in accordance with the present invention' Figure 2 is a side elevation view of the combination of the transducer casing or housing of Figure 1, together with the crystal detecting element and its cable connections; and iO~ '7 Figure 3 lllustrates a typical service application for acoustic emission transducers constructed and arranged in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to Fig. 1, there is shown a machined metal housing or casing generally designated 10, which com-prises a cylindrically shaped body 12 having formed in a wall thereof at its upper end an opening in which is secured a cable inlet channel 14. The channel 14 comprises a tubular member disposed substantially perpendicular to the wall of cylindrical body 12, including an opening 16 for receiving the signal cable 18 (See Fig. 2) therein, and may be secured in place by welding or other suitable fastening means, or integrally formed with the housing. The adjacent or top end of the housing is open and has formed therewith an annular shelf or ledge`20 for seating a circular lid 22 which can be sealed in place by suitable means such as an epoxy cement to the housing once the crystal detecting ele-ment 24 is located therein as described hereinafter. At the bottom or affixing end of the transducer housing there is provided a portion comprising an integral wearplate 26 ~nd a lens 28. The wearplate essentially comprises the bottom or mounting surface of the transducer which permits it to be bonded to the structural surface of the pressure vessel or other structure under anal~sis for structural integrity. Located at the bottom or same end as the wear-plate is the lens 28 which is integral with the wearplate and comprises a truncated conical configuration. m e sides 30 of the lens extend upw~rd toward the open end sloping from the wearplate end of the housing radially inward, ~.0~ 77 preerably at an angle of about 45 with the vertical ax.is and walls of the housing. As best shown in Fig, 2, the crystal detecting element 24 is bonded at 32 to the upper or platform surface 34 of the lens by a suitable epoxy cement. The tapered configuration of the lens 28 from the wearplate in the direction toward - 6a -iO~,77 the open end or crystal serves to concentrate energy received from acoustic emission signals onto the crystal detecting element. The element typically may comprise a piezoelectric crystal which is connected through electrical connections 36 to the signal cable 18 which extends through the opening 16 into the interior of the housing. After the connections between the crystal detecting element and the signal cable are made, the lens cover or lid 22 is secured in place on the ledge 20 at the open end of the housing. One suitable material for the casing is stainless steel.
As shown in Fig. 2, the cable is secured in place in the cable inlet by means of a standard shring tubing seal generally designated 38. The signal cable extends through the seal and is connected as ~i~cussed hereinafter. Fig. 3 illustrates a typical location of the acoustic emission trans-ducers 10 constructed in accordance with the teachings of the present invention, secured to the surface 40 of a structure 42 under stress, usually at operating pressure or above, e.g., a pressure vessel. The transducers are placed at appropriate locations which correspond to pertinent physical features of the structure. For most pressure vessels ordinarily twelve to sixteen transducers should be sufficient, and less (four to six) for less complex structures. The transducers normally are situated along the length and circumferentially about the surface of the structure in order to detect acoustic emissions generated by the material under stress within the structure. The transducers are positioned on the structural surfaces and held in position with a magnetic mount or epoxy or tape. The installation may be temporary for duration of the test anl~ the transducers removed follow-ing analysis, or premanent if desired for frequent or 1ill~`1677 continuous analysis of the structure. The pieeoelectric element mounted on the inner or platform surface of the wearplate-lens detects the acoustic emission sounds which travel through the structure material and are coupled through the mounting to the transducer. Each transducer has a low noise, high gain amplifier 44 (per se conventional) which boosts or amplifies detected signals. These amplified signals are in turn transmitted via signal cabling 46 to a unit 48 where signal conditioning, processing and analysis takes place. Typically this may include monitoring of the amount of acoustic energy per unit stress being released from the structure and computer subsystems for determining significance and location of a defect. This may be done by placing an acetate overlay bearing scaled outline drawings of the system components under analysis over the computer display -to pinpoint precise locations of defects such as discontinuities.
While a preferred embodiment of the present invention has been shown, various modifications and variations in the construction and/or arrangement of the invention may present themselves to those skilled in the art upon a reading of this disclosure. It is intended that such variations and/or modifications fall within the scope of the present inven-tion which is better defined by reference to the appended claims.
Claims (10)
1. An acoustic emission transducer comprising a crystal detector element for sensing acoustic emissions, a cylindrical metal housing for said crystal detector element, said housing having a main axis and comprising a bottom wearplate end integ-ral with said housing and an opposite open end, said bottom end including a lens portion integral with said wearplate and located internally of said housing and comprising tapered sides having a slope inward toward said main axis extending from said wearplate toward said open end for concentrating energy received from the sensed emissions onto said crystal detector element and terminating in a planar surface at a fixed distance from said wearplate end axially spaced therefrom, and means securing said crystal detector element to said planar surface.
2. The transducer of claim 1 wherein said sides taper in-wardly at 45° relative to said main axis of said housing.
3. The transducer of claim 1 including a ledge located at said open end and lid means secured to said ledge for sealing said crystal detector element within said housing.
4. The transducer of claim 1 in combination with a struc-ture under stress and having said transducer secured thereto at various locations on the surface thereof.
5. The transducer of claim 1 wherein said lens and wear-plate are unitary with said housing.
6. The transducer of claim 1 wherein said housing com-prises a cylindrical body.
7, The transducer of claim 1 wherein said housing includes a tubular member secured adjacent said opening end.
8. A system for use in detecting acoustic signals emitted from a pressure system under stress comprising in combination: a structural surface under stress and having a plurality of acoustic transducer members mounted in pre-determined spaced relation on said surface for monitoring the amount of energy per unit stress being released from said system, means for mounting a first end of said trans-ducers to said surface such that the acoustic signals indicative of the system stress are coupled to said acoustic transducer members, each of said transducer members com-prising a cylindrical metal housing having a main axis and comprising a bottom wearplate end integral with said hous-ing and a crystal element mounted therein for sensing said acoustic signals coupled through said housing, a frusto-conically-shaped lens portion integral with said wearplate and said housing and located internally of said housing adjacent said first end thereof mounted to said surface and having tapered side walls which slope inwardly from said first end toward said main axis extending in the direction from said first end toward a second open end of said housing opposite said first end, said side walls termin-ating in an internal element mounting platform surface axially spaced from said first end, said crystal element secured to said platform surface, the tapered configuration of said lens portion concentrating energy received from said acoustic signals onto said crystal element.
9. The system of claim 8 including amplifier means connected to said crystal element in each of said transducer members for receiving and amplifying signals produced by said elements.
10. The system of claim 8 wherein the mounting means comprises an epoxy bonding the wearplate of said housing to said surface.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US57744275A | 1975-05-14 | 1975-05-14 | |
| US577,442 | 1975-05-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1094677A true CA1094677A (en) | 1981-01-27 |
Family
ID=24308756
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA250,548A Expired CA1094677A (en) | 1975-05-14 | 1976-04-20 | Acoustic emission transducer and system |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS51138484A (en) |
| BE (1) | BE841813A (en) |
| CA (1) | CA1094677A (en) |
| DE (1) | DE2617462A1 (en) |
| ES (1) | ES447865A1 (en) |
| FR (1) | FR2311300A1 (en) |
| GB (1) | GB1543226A (en) |
| IT (1) | IT1059249B (en) |
| SE (1) | SE7605425L (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4088907A (en) * | 1976-10-29 | 1978-05-09 | Westinghouse Electric Corp. | Piezoelectric acoustic emission instrumentation |
| AU534645B2 (en) * | 1979-02-27 | 1984-02-09 | Australasian Training Aids Pty. Ltd. | Transducer assemblies |
| US4530241A (en) * | 1979-04-24 | 1985-07-23 | European Atomic Energy Community (Euratom) | Method of monitoring the identity and integrity of an object particularly a closed container |
| FR2518751A1 (en) * | 1981-12-22 | 1983-06-24 | Euratom | SYSTEM FOR MONITORING A PLURALITY OF CONTAINERS USING ULTRASONIC SEALS |
| US4468965A (en) * | 1982-11-05 | 1984-09-04 | Union Carbide Corporation | Test method for acetylene cylinders |
| GB2269900A (en) * | 1992-08-19 | 1994-02-23 | Christopher David Hill | Acoustic leak detection method for liquid storage tanks |
| FR2765324B1 (en) * | 1997-06-25 | 1999-09-17 | Framatome Sa | METHOD AND DEVICE FOR REMOTELY MEASURING DEFORMATIONS IN SERVICE OF A CASING OF A TUBE BEAM OF A HEAT EXCHANGER |
| CN113465732B (en) * | 2021-08-13 | 2022-04-05 | 重庆大学 | Vibration table structure displacement response prediction method and device based on EMD-DNN |
| CN113465733B (en) * | 2021-08-13 | 2022-04-05 | 重庆大学 | Vibration table structure displacement response prediction method and device based on EEMD-DNN |
-
1976
- 1976-04-20 CA CA250,548A patent/CA1094677A/en not_active Expired
- 1976-04-21 DE DE19762617462 patent/DE2617462A1/en not_active Withdrawn
- 1976-04-26 GB GB16788/76A patent/GB1543226A/en not_active Expired
- 1976-04-30 IT IT22881/76A patent/IT1059249B/en active
- 1976-05-11 JP JP51052880A patent/JPS51138484A/en active Pending
- 1976-05-12 SE SE7605425A patent/SE7605425L/en unknown
- 1976-05-13 BE BE167018A patent/BE841813A/en unknown
- 1976-05-13 FR FR7614506A patent/FR2311300A1/en active Granted
- 1976-05-13 ES ES447865A patent/ES447865A1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2617462A1 (en) | 1976-11-25 |
| BE841813A (en) | 1976-11-16 |
| FR2311300A1 (en) | 1976-12-10 |
| FR2311300B3 (en) | 1980-10-24 |
| SE7605425L (en) | 1976-11-15 |
| ES447865A1 (en) | 1977-12-01 |
| GB1543226A (en) | 1979-03-28 |
| IT1059249B (en) | 1982-05-31 |
| JPS51138484A (en) | 1976-11-30 |
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