CA1189945A - Device for the activation of an apparatus for measuring acoustic emission by detection of background noise - Google Patents
Device for the activation of an apparatus for measuring acoustic emission by detection of background noiseInfo
- Publication number
- CA1189945A CA1189945A CA000381095A CA381095A CA1189945A CA 1189945 A CA1189945 A CA 1189945A CA 000381095 A CA000381095 A CA 000381095A CA 381095 A CA381095 A CA 381095A CA 1189945 A CA1189945 A CA 1189945A
- Authority
- CA
- Canada
- Prior art keywords
- background noise
- acoustic emission
- detection
- detection circuit
- activation
- 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
- G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
-
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D7/00—Indicating measured values
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H1/00—Measuring characteristics of vibrations in solids by using direct conduction to the detector
Abstract
A DEVICE FOR THE ACTIVATION OF AN
APPARATUS FOR MEASURING ACOUSTIC EMISSION
BY DETECTION OF BACKGROUND NOISE
Abstract of the Disclosure An apparatus for measuring acoustic emission is activated only at critical periods which are determined by detection of the background noise from a reference level. An acoustic emission transducer continuously transmits a signal to a detection circuit which delivers the top modulation envelope of the background noise to a comparator at a reference level delivered by a control unit. When the mean level of the background noise exceeds the reference level, the comparator delivers a signal which activates the input/output assembly of the measuring apparatus.
APPARATUS FOR MEASURING ACOUSTIC EMISSION
BY DETECTION OF BACKGROUND NOISE
Abstract of the Disclosure An apparatus for measuring acoustic emission is activated only at critical periods which are determined by detection of the background noise from a reference level. An acoustic emission transducer continuously transmits a signal to a detection circuit which delivers the top modulation envelope of the background noise to a comparator at a reference level delivered by a control unit. When the mean level of the background noise exceeds the reference level, the comparator delivers a signal which activates the input/output assembly of the measuring apparatus.
Description
This invention relates to a device for the activation of an apparatus which serves to measure acoustic emission by detection of background noise. The invention finds an application in the field of industrial control by acoustic emission.
In industrial installations subjected to high stresses, there exist a certain number of sound-generating phenomena in which sounds are propagated in structures and which are of two types :
- percussion impacts of solid portions on stationary obstacles (detachment of turbine blade), - crack formation (in concrete blocks).
Different types of sounds or noises are also propagated in other frequency bands. Noteworthy examples are noises arising from the flow of fluids in piping systems, vibrations of unbalanced rotating parts) and so on. Systems for acquisition of data by acoustic emission must therefore store a large number of unnecessary data.
In fact, in the example of a fluid circuit with a pump, the potential danger of projection of solid particles appears as critical only if the pump is in operation. In acquisition systems of the prior art, all that takes place prior to startup of the pump will be recorded without distinction.
In order to overcome this major drawback, the aim of this invention is to provide a device for the L89~S
activation of an apparatus which serves -to measure acoustic emission by detection of background noise. Said device carries out a continuous measurement of environ-mental background noise by means of piezoelectric trays-dupers, compares said noise with a reference voltage within a comparator which then activates the measuring apparatus.
Other features of the invention will be more apparent upon consideration of the following description and accompanying drawings, wherein :
- Fig. 1 is a diagram of a device according to the invention ;
Figs. pa and 2b are two operating diagrams.
The device according to the invention as shown in Fig. 1 comprises a comparator 3 which receives at one input a reference voltage delivered by a control unit and which receives at the other input a signal delivered by a circuit 2 for detecting electrical pulses produced by an acoustic emission transducer 1. This detection circuit
In industrial installations subjected to high stresses, there exist a certain number of sound-generating phenomena in which sounds are propagated in structures and which are of two types :
- percussion impacts of solid portions on stationary obstacles (detachment of turbine blade), - crack formation (in concrete blocks).
Different types of sounds or noises are also propagated in other frequency bands. Noteworthy examples are noises arising from the flow of fluids in piping systems, vibrations of unbalanced rotating parts) and so on. Systems for acquisition of data by acoustic emission must therefore store a large number of unnecessary data.
In fact, in the example of a fluid circuit with a pump, the potential danger of projection of solid particles appears as critical only if the pump is in operation. In acquisition systems of the prior art, all that takes place prior to startup of the pump will be recorded without distinction.
In order to overcome this major drawback, the aim of this invention is to provide a device for the L89~S
activation of an apparatus which serves -to measure acoustic emission by detection of background noise. Said device carries out a continuous measurement of environ-mental background noise by means of piezoelectric trays-dupers, compares said noise with a reference voltage within a comparator which then activates the measuring apparatus.
Other features of the invention will be more apparent upon consideration of the following description and accompanying drawings, wherein :
- Fig. 1 is a diagram of a device according to the invention ;
Figs. pa and 2b are two operating diagrams.
The device according to the invention as shown in Fig. 1 comprises a comparator 3 which receives at one input a reference voltage delivered by a control unit and which receives at the other input a signal delivered by a circuit 2 for detecting electrical pulses produced by an acoustic emission transducer 1. This detection circuit
2 can consist of a mean noise level integrator which serves to provide the positive peak envelope of the background noise or so-called noise level.
When the noise level is below the level of the reference which has been chosen, the comparator is at zero When the noise level rises above the reference, the comparator changes state and initiates the operation of the measuring apparatus which then processes the signals received from the different transducers.
The increase in noise level is caused in particular by the commencement of a critical phase of operation of the installation which is being monitored.
In the case of a fluid circuit, startup of the pump in-dupes a background noise. This noise is detected by the circuit 2, then turns-on the comparator 3, and the control unit 4 delivers a suitably selected reference.
Referring now to Fig. pa, this figure shows the zero voltage level 10, the background noise 8, the noise modulation 7 and the reference voltage 9. fig. 2b shows the zero voltage level 12 and the response of the comparator 3 when the modulation 7 is higher than the reference 9, whereupon the comparator emits a signal. Thus the rectangular wave 15 is the response of the comparator
When the noise level is below the level of the reference which has been chosen, the comparator is at zero When the noise level rises above the reference, the comparator changes state and initiates the operation of the measuring apparatus which then processes the signals received from the different transducers.
The increase in noise level is caused in particular by the commencement of a critical phase of operation of the installation which is being monitored.
In the case of a fluid circuit, startup of the pump in-dupes a background noise. This noise is detected by the circuit 2, then turns-on the comparator 3, and the control unit 4 delivers a suitably selected reference.
Referring now to Fig. pa, this figure shows the zero voltage level 10, the background noise 8, the noise modulation 7 and the reference voltage 9. fig. 2b shows the zero voltage level 12 and the response of the comparator 3 when the modulation 7 is higher than the reference 9, whereupon the comparator emits a signal. Thus the rectangular wave 15 is the response of the comparator
3 at the modulation peak 16.
In some instances, background noises other than the noise which serves to trigger the comparator may con-eeivably appear. In the example of a fluid circuit, thebaekground noise which activates the measuring apparatus is the noise emitted by the pump. At some distance away and externally of the circuit, another background noise which appears at a sufficient level may reactivate the measuring apparatus. In order to forestall such an event, discrimination by s~eetral correlation is carried out prior to detection of modulation by the detector circuit 2.
The acoustic emission frequency spectrum is in fact characteristic of the emission source to a large extent.
It is therefore possible to select the access to the detection circuit only in respect of those background noises which are correlated with a predetermined reference spectrum.
The spectrum correlator can be connected to the input of the device downstream of the transducer 1 and can either enable or inhibit the detection circuit 2 via a special input of said circuit.
The data acquisition assembly 5 forms an integral part of the complete detection apparatus to which the activation device according to the invention is coupled. Said assembly comprises in particular a time base for acquisition of data which will then be processed in the processing assembly 6. The acquisition time base can thus be of the variable frequency type. Thus, when the activation device according to the invention does not detect any background noise which is capable of turning it on, that is to say when the noise level is below the pro-determined critical threshold value or the reference unit 4, the acquisition time base produces a relatively low pro-determined frequency f. By way of example, the data acquisition assembly 5 then carries out low-rate sampling of the signals derived from the transducer 1 at intervals 9~5 of l/f seconds. When a high noise level is recorded, the signal emitted by the comparator 3 switches the acquisition time base to an operating frequency F which is distinctly higher than the so-called watch frequency f. The sampling operation will then be much faster, namely at intervals of l/F seconds. The flow of data -to be processed is then increased by a marked extent.
The present invention therefore makes it possible to perform selective monitoring of various acoustic emissions in an industrial installation which may be of large size. This may be carried out as a function of predetermined hazard thresholds in order to limit the number of monitoring data collected by the transducer 1 when there is only a low degree of probability that these latter will be accident effects.
The activation device according to the invention can assume a number of different forms according to the various configurations of the apparatus for measuring acoustic emission. Thus, if the measuring apparatus comprises a large number of transducers whereas the installation under control has only a single source of noise which may become critical, the activation device according to the invention will be placed on only one of the transducers which is suitably chosen for the purpose.
The other transducers will be directly connected to the assembly 5 for acquisition of data to be processed.
39~5 If a number of different background noises are indications of critical thresholds, the group of trays-dupers can be arranged in separate subassemblies. One activation device and one data acquisition assembly 5 are associated with each transducer subassembly.
Furthermore, the present invention applies to different chains for the acquisition of data of acoustic origin. The transducer 1 may thus comprise a preamplifier in the even-t of long distances at the transducer location.
The transducer 1 delivers electrical signals which can be rectified by a half-wave or full-wave rectifier device, for example of the semiconductor diode type.
In some instances, background noises other than the noise which serves to trigger the comparator may con-eeivably appear. In the example of a fluid circuit, thebaekground noise which activates the measuring apparatus is the noise emitted by the pump. At some distance away and externally of the circuit, another background noise which appears at a sufficient level may reactivate the measuring apparatus. In order to forestall such an event, discrimination by s~eetral correlation is carried out prior to detection of modulation by the detector circuit 2.
The acoustic emission frequency spectrum is in fact characteristic of the emission source to a large extent.
It is therefore possible to select the access to the detection circuit only in respect of those background noises which are correlated with a predetermined reference spectrum.
The spectrum correlator can be connected to the input of the device downstream of the transducer 1 and can either enable or inhibit the detection circuit 2 via a special input of said circuit.
The data acquisition assembly 5 forms an integral part of the complete detection apparatus to which the activation device according to the invention is coupled. Said assembly comprises in particular a time base for acquisition of data which will then be processed in the processing assembly 6. The acquisition time base can thus be of the variable frequency type. Thus, when the activation device according to the invention does not detect any background noise which is capable of turning it on, that is to say when the noise level is below the pro-determined critical threshold value or the reference unit 4, the acquisition time base produces a relatively low pro-determined frequency f. By way of example, the data acquisition assembly 5 then carries out low-rate sampling of the signals derived from the transducer 1 at intervals 9~5 of l/f seconds. When a high noise level is recorded, the signal emitted by the comparator 3 switches the acquisition time base to an operating frequency F which is distinctly higher than the so-called watch frequency f. The sampling operation will then be much faster, namely at intervals of l/F seconds. The flow of data -to be processed is then increased by a marked extent.
The present invention therefore makes it possible to perform selective monitoring of various acoustic emissions in an industrial installation which may be of large size. This may be carried out as a function of predetermined hazard thresholds in order to limit the number of monitoring data collected by the transducer 1 when there is only a low degree of probability that these latter will be accident effects.
The activation device according to the invention can assume a number of different forms according to the various configurations of the apparatus for measuring acoustic emission. Thus, if the measuring apparatus comprises a large number of transducers whereas the installation under control has only a single source of noise which may become critical, the activation device according to the invention will be placed on only one of the transducers which is suitably chosen for the purpose.
The other transducers will be directly connected to the assembly 5 for acquisition of data to be processed.
39~5 If a number of different background noises are indications of critical thresholds, the group of trays-dupers can be arranged in separate subassemblies. One activation device and one data acquisition assembly 5 are associated with each transducer subassembly.
Furthermore, the present invention applies to different chains for the acquisition of data of acoustic origin. The transducer 1 may thus comprise a preamplifier in the even-t of long distances at the transducer location.
The transducer 1 delivers electrical signals which can be rectified by a half-wave or full-wave rectifier device, for example of the semiconductor diode type.
Claims (5)
1. A device for measuring acoustic emission, wherein said device comprises a detection circuit for detecting the background noise collected by transducers of the measuring apparatus; means for comparing the sig-nal generated by said detection circuit with a reference voltage and producing an output signal when the compari-son indicates that the background noise level has increas-ed above a certain threshold level; and means for acquir-ing data at a first frequency, f, when no output signal is produced and,when said output signal is produced, acquiring data at a second frequency, F, greater than said first frequency, f.
2. A device according to claim 1, wherein the background noise detection circuit comprises a mean level integrator.
3. A device according to claim 1, wherein the background noise detection circuit comprises a correla-tor for receiving a signal which performs spectral discrimination.
4. A device according to claim 1 wherein the transducer further comprises a rectifier device.
5. A device according to claim 1, wherein the means for comparing the signal receive a reference voltage from a control unit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8015157A FR2486654A1 (en) | 1980-07-08 | 1980-07-08 | DEVICE FOR ACTIVATION OF ACOUSTIC TRANSMITTING MEASURING DEVICE BY DETECTING THE SUBSTANTIAL NOISE |
| FR8015157 | 1980-07-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189945A true CA1189945A (en) | 1985-07-02 |
Family
ID=9243974
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000381095A Expired CA1189945A (en) | 1980-07-08 | 1981-07-03 | Device for the activation of an apparatus for measuring acoustic emission by detection of background noise |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4423634A (en) |
| EP (1) | EP0043746B1 (en) |
| KR (1) | KR850000356B1 (en) |
| CA (1) | CA1189945A (en) |
| DE (1) | DE3167427D1 (en) |
| ES (1) | ES503720A0 (en) |
| FR (1) | FR2486654A1 (en) |
| YU (1) | YU167281A (en) |
Families Citing this family (33)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH065193B2 (en) * | 1987-04-28 | 1994-01-19 | 光洋精工株式会社 | Bearing remaining life prediction device |
| US4846001A (en) * | 1987-09-11 | 1989-07-11 | Sps Technologies, Inc. | Ultrasonic load indicating member |
| US4899591A (en) * | 1987-09-11 | 1990-02-13 | Sps Technologies, Inc. | Ultrasonic load indicating member, apparatus and method |
| US5116515A (en) * | 1991-04-24 | 1992-05-26 | Soil Guardian Inc. | Process and apparatus for removing volatile organic compounds from contaminated vadose soil areas |
| US5278774A (en) * | 1991-10-01 | 1994-01-11 | Rockwell International Corporation | Alarm for transient underwater events |
| DE19518409C1 (en) * | 1995-05-19 | 1996-10-02 | Bosch Gmbh Robert | Acoustic fault identification for determining e.g. bearing damage from radially measured air sound signal |
| US5804726A (en) * | 1995-10-16 | 1998-09-08 | Mtd Products Inc. | Acoustic signature analysis for a noisy enviroment |
| US8290721B2 (en) * | 1996-03-28 | 2012-10-16 | Rosemount Inc. | Flow measurement diagnostics |
| US7630861B2 (en) * | 1996-03-28 | 2009-12-08 | Rosemount Inc. | Dedicated process diagnostic device |
| US7623932B2 (en) * | 1996-03-28 | 2009-11-24 | Fisher-Rosemount Systems, Inc. | Rule set for root cause diagnostics |
| DE19730716A1 (en) * | 1996-10-21 | 1998-04-23 | Fraunhofer Ges Forschung | Triggering a measurement procedure for quality assessment of audio and / or speech signals |
| US6507790B1 (en) | 1998-07-15 | 2003-01-14 | Horton, Inc. | Acoustic monitor |
| DE19948196A1 (en) | 1999-10-06 | 2001-05-17 | Aloys Wobben | Process for operating a wind farm |
| DE19948194C2 (en) * | 1999-10-06 | 2001-11-08 | Aloys Wobben | Process for monitoring wind turbines |
| DE10115267C2 (en) * | 2001-03-28 | 2003-06-18 | Aloys Wobben | Method for monitoring a wind energy plant |
| US7627441B2 (en) | 2003-09-30 | 2009-12-01 | Rosemount Inc. | Process device with vibration based diagnostics |
| US7523667B2 (en) * | 2003-12-23 | 2009-04-28 | Rosemount Inc. | Diagnostics of impulse piping in an industrial process |
| JP5312806B2 (en) * | 2005-02-28 | 2013-10-09 | ローズマウント インコーポレイテッド | Process device diagnostic apparatus and diagnostic method |
| US8112565B2 (en) | 2005-06-08 | 2012-02-07 | Fisher-Rosemount Systems, Inc. | Multi-protocol field device interface with automatic bus detection |
| US20070068225A1 (en) * | 2005-09-29 | 2007-03-29 | Brown Gregory C | Leak detector for process valve |
| US7913566B2 (en) * | 2006-05-23 | 2011-03-29 | Rosemount Inc. | Industrial process device utilizing magnetic induction |
| US7953501B2 (en) * | 2006-09-25 | 2011-05-31 | Fisher-Rosemount Systems, Inc. | Industrial process control loop monitor |
| US8788070B2 (en) | 2006-09-26 | 2014-07-22 | Rosemount Inc. | Automatic field device service adviser |
| EP2074385B2 (en) | 2006-09-29 | 2022-07-06 | Rosemount Inc. | Magnetic flowmeter with verification |
| US8898036B2 (en) * | 2007-08-06 | 2014-11-25 | Rosemount Inc. | Process variable transmitter with acceleration sensor |
| US7590511B2 (en) * | 2007-09-25 | 2009-09-15 | Rosemount Inc. | Field device for digital process control loop diagnostics |
| US8250924B2 (en) * | 2008-04-22 | 2012-08-28 | Rosemount Inc. | Industrial process device utilizing piezoelectric transducer |
| US7977924B2 (en) * | 2008-11-03 | 2011-07-12 | Rosemount Inc. | Industrial process power scavenging device and method of deriving process device power from an industrial process |
| GB2488092B (en) | 2010-11-03 | 2014-10-29 | Kittiwake Developments Ltd | A sensor based means of monitoring the mechanical condition of rotating machinery that operates intermittently |
| US9207670B2 (en) | 2011-03-21 | 2015-12-08 | Rosemount Inc. | Degrading sensor detection implemented within a transmitter |
| US9052240B2 (en) | 2012-06-29 | 2015-06-09 | Rosemount Inc. | Industrial process temperature transmitter with sensor stress diagnostics |
| US9602122B2 (en) | 2012-09-28 | 2017-03-21 | Rosemount Inc. | Process variable measurement noise diagnostic |
| EP3370074B1 (en) | 2016-11-02 | 2020-03-18 | Shenzhen Goodix Technology Co., Ltd. | Method for detecting background noise of sensor, and device thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3841144A (en) * | 1972-10-12 | 1974-10-15 | Mobil Oil Corp | Sand detection probe |
| JPS5850397B2 (en) * | 1976-04-23 | 1983-11-10 | 三菱電機株式会社 | Signal determination device that determines abnormal signals, etc. |
| US4111035A (en) * | 1977-11-07 | 1978-09-05 | General Motors Corporation | Engine knock signal generating apparatus with noise channel inhibiting feedback |
-
1980
- 1980-07-08 FR FR8015157A patent/FR2486654A1/en active Granted
-
1981
- 1981-06-10 DE DE8181400919T patent/DE3167427D1/en not_active Expired
- 1981-06-10 EP EP81400919A patent/EP0043746B1/en not_active Expired
- 1981-07-03 CA CA000381095A patent/CA1189945A/en not_active Expired
- 1981-07-06 US US06/280,355 patent/US4423634A/en not_active Expired - Fee Related
- 1981-07-07 KR KR1019810002459A patent/KR850000356B1/en active IP Right Grant
- 1981-07-07 ES ES503720A patent/ES503720A0/en active Granted
- 1981-07-08 YU YU01672/81A patent/YU167281A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| FR2486654B1 (en) | 1983-08-05 |
| EP0043746B1 (en) | 1984-11-28 |
| KR830006685A (en) | 1983-10-06 |
| US4423634A (en) | 1984-01-03 |
| EP0043746A1 (en) | 1982-01-13 |
| FR2486654A1 (en) | 1982-01-15 |
| ES8205464A1 (en) | 1982-06-01 |
| YU167281A (en) | 1983-06-30 |
| DE3167427D1 (en) | 1985-01-10 |
| ES503720A0 (en) | 1982-06-01 |
| KR850000356B1 (en) | 1985-03-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |