EP2269096A1 - Dispositif à fonctionnement numérique pour détecter des éléments conducteurs métalliques - Google Patents

Dispositif à fonctionnement numérique pour détecter des éléments conducteurs métalliques

Info

Publication number
EP2269096A1
EP2269096A1 EP09735434A EP09735434A EP2269096A1 EP 2269096 A1 EP2269096 A1 EP 2269096A1 EP 09735434 A EP09735434 A EP 09735434A EP 09735434 A EP09735434 A EP 09735434A EP 2269096 A1 EP2269096 A1 EP 2269096A1
Authority
EP
European Patent Office
Prior art keywords
signal
digital
analog
coil system
detection signal
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.)
Ceased
Application number
EP09735434A
Other languages
German (de)
English (en)
Inventor
Manfred Artinger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mesutronic Geraetebau GmbH
Original Assignee
Mesutronic Geraetebau GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mesutronic Geraetebau GmbH filed Critical Mesutronic Geraetebau GmbH
Publication of EP2269096A1 publication Critical patent/EP2269096A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
    • G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
    • G01V3/104—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils

Definitions

  • the invention relates to a device for generating a detection signal in the presence of metallically conductive parts in an at least substantially non-conductive flow.
  • Devices of this type usually operate in such a way that with an alternator via a transmitting coil system in a monitored portion of the flow an alternating electromagnetic field is built up, the triggered when passing a part signal changes are detected by a receiving coil system and by means of a subsequent evaluation circuit for deriving a detection signal serve, which triggers an information and / or an excretion of the part.
  • Such devices are known, for example, by the German Offenlegungsschriften 37 14 009 Al and 40 171 780 Al and the prior art mentioned therein in terms of their application and their structure.
  • the detection signal is used to actuate protective devices, such as optical and / or acoustic signal means of defeat of the conveyor, or for redirecting the flow containing a disturbing part flow in a collection vessel or the like.
  • protective devices such as optical and / or acoustic signal means of defeat of the conveyor, or for redirecting the flow containing a disturbing part flow in a collection vessel or the like.
  • the evaluation for obtaining the detection signal can be made not only on an analog but also on a digital basis.
  • a respective phase signal derived in analogue form and an amplitude signal are generated from the output signal of the receiver coil system which is in analog form and fed to the evaluation. Both in the analog and in the digital working design, external disturbances can cause difficulties.
  • the mentioned difficulties can according to a development of the invention means for generating a detection signal when metallic conductive parts in an at least largely non-conductive flow, in which a transmitter via a transmitter coil system in a monitored portion of the flow an electromagnetic alternating field is constructed, whose Passing a partially triggered signal change detected by a receiving coil system and serve with a subsequent, working on a digital basis evaluation circuit for deriving a detection signal that triggers an information and / or excretion of the part, also be countered by the fact that the transmitter is designed as a digital transmitter whose digital output signal is supplied to the transmitting coil system via a digital / analog converter, that the receiver coil system is associated with an analog / digital converter and the received signal transmission to the Auswe Digital circuit is performed, and that the present digital signal received signal and the digital form present signal of the digital transmitter of the evaluation circuit for deriving the detection signal are supplied.
  • An advantageous embodiment is characterized in that the sampling rate of the analog / digital conversion is selected to be so high that at least one half-wave of the output by the alternating current generator is still resolvable. Furthermore, it is advantageous if the analog / digital converter for the analog received signal is preceded by an analog amplifier. For this purpose, it has proven to be advantageous if a 16-bit / AD converter is provided as the analog / digital converter and the amplifier has a gain factor of more than 50, preferably of about 100.
  • FIG. 1 shows the view of a metal detection device which encloses a conveyor belt B
  • Figure 2 shows a section through a metal detection device according to the figure 1
  • Figure 3 is a circuit diagram with a transmitting coil and a two-coil Spulensyste ⁇ t for the reception
  • the Figure 4 is a vibration diagram illustrating the effect of conductive parts in bingogutstrom on the signal received via the receiving coil system
  • Figure 5 is a block diagram of a circuit for deriving a detection signal
  • Figure 6 shows the time course of the occurring during the passage of a metallically conductive part signal at the output
  • FIG. 7 shows an arrangement according to the invention with an A / D converter at the output of the receiver coil system and an A / D converter of the analog alternator
  • FIG. 8 shows a block diagram for an inventive circuit trained metal detection device with a digital alternating current generator.
  • the device shown schematically in Figures 1 and 2 consists of two parts OT and UT, of which one is U-shaped and the other designed as a flat support.
  • the two parts enclose a conveyor belt B, which in the direction of the recorded arrow can transport the material to be inspected for unwanted metallic parts, such as a nut M or metal foil F, through the device.
  • a transmission coil Sl is arranged in the part upper part OT.
  • metallically conductive parts are arranged in the support UT.
  • two receiving coils S2 and S3 offset in the conveying direction, arranged.
  • Embodiment and arrangement of the coils are, as well as the housing shape and adapted the shape and nature of the passage opening in a conventional manner the application. About not shown contacts their connections are made to the circuit A in the part OT.
  • a connection line AL serves to connect the device to the operating power supply.
  • An output line SL is used to forward a triggered by a part to be detected detection signal ES to one of the aforementioned protective devices.
  • the transmission coil S1 and the coil pair S2, S3 are each completed by a capacitor C2 to form an electrical resonant circuit.
  • the two oscillatory circuits Sl, Cl and S2, S3, C2 are tuned so that they form a tuned to the frequency of the alternating current bandpass filter, which is supplied from the generator G.
  • FIG. 4 shows the influence of the passage of a metallically conductive part moved by the conveyor belt past the coils S2 and S3.
  • the eddy currents caused by the alternating field of the coil change both the amplitude and the phase position of the signal Uemp received via S2 and S3, which is phase-shifted by 90 ° against use without such field disturbances.
  • the changes are indicated by arrows.
  • the amplitude change is evaluated via AZ and the phase change via PZ - as can be seen from FIG.
  • the circuit A begins, as the figure 5 shows, with a - serving as a receiver - formed by a so-called operational amplifier differential amplifier OP, at its output a division into an amplitude branch AZ and a phase branch PZ is made.
  • a - serving as a receiver - formed by a so-called operational amplifier differential amplifier OP
  • a phase branch PZ is made in the amplitude branch AZ.
  • the peak value of the signal Uemp is determined by means of a rectifier stage SG.
  • phase branch PZ a phase discriminator PV is inserted, to which the signal Use of the generator G is supplied as phase reference signal.
  • the output voltages of SG and PV are fed to a comparator K with adjustable weighting. In the simplest case, this is a subtractor with an amplitude controller in at least one of its two inputs.
  • the output signal of the comparator K is, optionally after an intermediate amplification in an amplifier V, fed via a filter F of a threshold SS, at the output then the detection signal AS of a metallically conductive part can be removed, which is disturbing is classify.
  • the threshold value circuit SS is supplied with a reference voltage Usch which can be set in the value, at the crossing of which the detection signal AS occurs in the output of SS.
  • the filter F suppresses the DC component in the output of K and limits the frequency spectrum to the intended range for the evaluation.
  • the circuit section from the output of OP to the output of SS forms, so to speak, the evaluation device.
  • the evaluation circuit begins, as shown in FIG. 5, behind the differential amplifier OP serving as a receiver, formed by a so-called operational amplifier, at the output of which a division into an amplitude branch AZ and a phase branch PZ is made.
  • the amplitude branch AZ the absolute value of the signal Uemp, which represents the amplitude change signal AS, is determined by means of a stage SG.
  • the phase branch PZ a phase discriminator PV is inserted, which receives the signal Use of the generator G as a phase reference signal. At the output of PV, the phase change signal PS is on.
  • FIG. 6 diagrammatically shows the influence of the passage of a metallically conductive part moved past the coil S2 through the conveyor belt.
  • the eddy currents caused by the alternating field Use of the coil Sl in the part change both the amplitude and the phase position of the signal Uemp received via S2 and S3, which is phase-shifted by 90 ° against Use without such field disturbances.
  • the change ranges are indicated by arrows.
  • FIG. 6 shows the effect of the reference voltage Usch in the threshold circuit SS. Only when the threshold values are exceeded does an output signal AS appear, which serves as a detection signal.
  • Such threshold circuits are known per se.
  • the threshold value circuit also effectively suppresses an influence of the noise floor, which is indicated in the figure as preceding and following the actual signals.
  • an analog / digital converter 1 is connected to the output of the receiver coil system, to which preferably an analogue amplifier is connected. stronger 2 upstream.
  • the signals U1, U2 recorded by the receiver coil system S2, S3 are transmitted as a signal in digital form to the comparator 6 of an evaluation unit 4.
  • a transmission signal component is removed and fed to an analog / digital converter 3.
  • Its digital output signal is supplied as a second input signal to a digitally operating comparator 6 of the evaluation unit 4 to form a detection signal.
  • the transducers 1, 3 are preferably designed such that they emit unipolar output signals.
  • the digital signal in the output of the comparator 6 (see K in Figure 5) is then further processed using digitally operating components, such as a filter 7, etc. to the detection signal AS.
  • the A / D converter 1 is arranged as close as possible to the receiving coil system S2, S3. As a result, disturbing signal interference is prevented.
  • the digital remainder path from the output of the converter 1 to the input of the evaluation unit 4, on the other hand, is much less sensitive.
  • the sampling rate of the analog-to-digital conversion that is the sampling frequency for taking amplitude samples from the analog signal, is selected to be high enough to resolve at least one half cycle of the alternator output according to the known sampling theorem. It is recommended a sampling frequency of about 1 megahertz to ensure universal use for a variety of applications. Namely, there is a mutual dependence between the sampling rate and the amplification factor. It has proved to be advantageous if a 16-bit / AD converter is provided as the analog / digital converter and the amplifier has a gain factor of more than 50, preferably 100.
  • FIG. 8 The block diagram of Figure 8 shows a further advantageous embodiment including the interconnection of the individual components.
  • the reference numerals are used in accordance with FIG. 7.
  • S2 From the receiving coil system Sl, S2 leads a line to the analog / digital converter 1, which is a high-resolution A / D converter.
  • an alternating-current generator 5 ' In the evaluation unit 4 provided with the comparator 6, an alternating-current generator 5 ', not shown in detail, is provided, which unlike the embodiment according to FIG. 7, outputs its signal as a digital signal.
  • Such generators are known, for example, from the book by Horst Geschwinde "Introduction to PLL Technology", Vieweg-Verlag, 1978.
  • This transmission signal is via a digital / analog converter 8 as an analog signal of the transmitting coil Sl fed.
  • a filter 7 designed as a digital component is also provided in this embodiment as well.
  • the data connection for the signal exchange between the individual system components takes place in the embodiments by means of a bus system, in particular based on the known Ethernet system.
  • the individual system components are assigned so-called “controllers”, which are control blocks with memory properties.
  • controllers which are control blocks with memory properties.
  • a preamplification of the analog receive coil signal prior to the formation of the phase and amplitude signals requires a high gain, for example, of about 10 5 and more.
  • ie conversion of the received coil signal into a digital signal and subsequent formation of phase signal and amplitude signal in the digital region of the overall circuit using a 16-bit analog / digital converter and a pre-amplification of the received coil signal of FIG 2 achieves a signal resolution of about 38 microvolts.
  • the operating unit and the associated display unit for the operating state has been omitted. These units are usually arranged on a remote from ergonomic reasons of the actual metal detector body.
  • the analog-to-digital conversion is provided at a short distance of less than a few decimetres from the receiving coils.
  • the actual evaluation circuit can then either be provided at a greater distance from it or combined with the analog / digital converter on a circuit board. In the latter case, then, this circuit module, for example, as in a device according to DE 195 21 266 in a lockable recess in the coil housing accommodated.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Electromagnetism (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

L'invention concerne un dispositif pour la génération d'un signal de reconnaissance en cas d'apparition d'éléments conducteurs métalliques dans un flux de transport au moins largement non conducteur. Selon l'invention, un générateur de courant alternatif (5) établit dans un segment à surveiller du flux de transport par le biais d'un système de bobine d'émission (S1) un champ alternatif électromagnétique dont les variations de signal déclenchées au passage d'un élément sont détectées par un système de bobines de réception (S2, S3) et servent à déduire, au moyen d'un circuit d'évaluation (4) à fonctionnement numérique placé en aval, un signal de reconnaissance qui déclenche l'envoi d'une information et/ou l'élimination de l'élément. Un convertisseur analogique/numérique (1) est affecté au système de bobines de réception (S2, S3) et la transmission du signal de réception vers le circuit d'évaluation (4) se fait numériquement. Une conversion analogique/numérique (3) est également prévue pour le signal du générateur de courant alternatif (5). Le signal de réception sous forme numérique et le signal du générateur de courant alternatif (5) sous forme numérique sont amenés au circuit d'évaluation (4) afin que le signal de reconnaissance en soit déduit.
EP09735434A 2008-04-23 2009-04-22 Dispositif à fonctionnement numérique pour détecter des éléments conducteurs métalliques Ceased EP2269096A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008020360 2008-04-23
PCT/EP2009/002934 WO2009130018A1 (fr) 2008-04-23 2009-04-22 Dispositif à fonctionnement numérique pour détecter des éléments conducteurs métalliques

Publications (1)

Publication Number Publication Date
EP2269096A1 true EP2269096A1 (fr) 2011-01-05

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP09735434A Ceased EP2269096A1 (fr) 2008-04-23 2009-04-22 Dispositif à fonctionnement numérique pour détecter des éléments conducteurs métalliques

Country Status (5)

Country Link
US (1) US20110109307A1 (fr)
EP (1) EP2269096A1 (fr)
CN (1) CN102016645A (fr)
DE (1) DE102009018387A1 (fr)
WO (1) WO2009130018A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011077068A1 (de) * 2011-06-07 2012-12-13 Hilti Aktiengesellschaft Verfahren und Vorrichtung zum Detektieren eines leitfähigen Objektes
CN114280402B (zh) * 2021-12-23 2023-11-03 安徽建国电力有限公司 一种耐磨抗腐蚀的铜铝稀土接地合金性能检测装置及方法

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WO1988003273A1 (fr) * 1986-10-23 1988-05-05 Peerless-Winsmith, Inc. Appareil de detection/identification
DE3714009A1 (de) 1987-04-27 1988-11-10 Hauni Werke Koerber & Co Kg Metalldetektor
GB2230611B (en) * 1989-03-30 1993-02-03 Cintex Ltd Product monitoring
DE4017178C2 (de) 1990-05-29 1993-11-25 Zdenek Weiss Trainingsgerät, insbesondere für Skilangläufer
DE4017780A1 (de) * 1990-06-01 1991-12-05 Sensoplan Messtechnik Gmbh Vorrichtung zum feststellen von relativ zu einer metallempfindlichen sensoranordnung bewegten metallteilen
DE19521266C1 (de) * 1995-06-10 1997-02-13 Mesutronic Geraetebau Gmbh Einrichtung zur Feststellung metallisch leitender Teile
JP3779508B2 (ja) * 1999-09-21 2006-05-31 アンリツ産機システム株式会社 金属検出機
GB2361544B (en) * 2000-04-20 2004-07-07 Goring Kerr Ltd Metal detector
US6559645B2 (en) * 2000-11-17 2003-05-06 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Detector apparatus and method
US6958603B2 (en) * 2001-09-21 2005-10-25 Tok Engineering Co., Ltd. Method for detecting metallic foreign matter and system for detecting metallic foreign matter
AT500093B8 (de) * 2002-08-01 2007-02-15 Mesutronic Geraetebau Gmbh Einrichtung zur feststellung störender teile in einem fördergut
KR100634648B1 (ko) * 2003-03-12 2006-10-16 안리츠 산키 시스템 가부시키가이샤 금속 검출 장치
WO2006021045A1 (fr) * 2004-08-26 2006-03-02 Minelab Electronics Pty Limited Procede et dispositif de detection de metaux par traitement de signaux numeriques
US7701204B2 (en) * 2004-09-15 2010-04-20 Allan Westersten Metal detector with reliable identification of ferrous and non-ferrous metals in soils with varying mineral content
GB2423366B (en) * 2005-02-16 2010-02-24 Cintex Ltd Metal detector

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Title
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Also Published As

Publication number Publication date
CN102016645A (zh) 2011-04-13
US20110109307A1 (en) 2011-05-12
DE102009018387A1 (de) 2010-06-02
WO2009130018A1 (fr) 2009-10-29

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