WO2015049766A1 - Metal-detection device - Google Patents

Metal-detection device Download PDF

Info

Publication number
WO2015049766A1
WO2015049766A1 PCT/JP2013/076985 JP2013076985W WO2015049766A1 WO 2015049766 A1 WO2015049766 A1 WO 2015049766A1 JP 2013076985 W JP2013076985 W JP 2013076985W WO 2015049766 A1 WO2015049766 A1 WO 2015049766A1
Authority
WO
WIPO (PCT)
Prior art keywords
determination
metal
lissajous waveform
inspection object
signal
Prior art date
Application number
PCT/JP2013/076985
Other languages
French (fr)
Japanese (ja)
Inventor
真彦 枝元
Original Assignee
株式会社システムスクエア
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 株式会社システムスクエア filed Critical 株式会社システムスクエア
Priority to PCT/JP2013/076985 priority Critical patent/WO2015049766A1/en
Publication of WO2015049766A1 publication Critical patent/WO2015049766A1/en

Links

Images

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
    • G01V3/105—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 forming directly coupled primary and secondary coils or loops

Definitions

  • the present invention relates to a metal detection apparatus including a transmission coil and a reception coil, and more particularly to a metal detection apparatus that can obtain a highly accurate inspection result using a Lissajous waveform.
  • an object to be inspected is supplied between a transmission coil and two reception coils, and the difference in induced power between the two reception coils is used as an output signal. can get.
  • the output signal is detected by the excitation signal of the transmission coil
  • the output signal is detected by a signal that is 90 degrees out of phase with the excitation signal.
  • Two detection outputs detected by signals with different phases are sent to the Lissajous waveform shaping unit, and a Lissajous waveform is drawn on the two-dimensional coordinates by the two detection outputs that change with the movement of the inspection object. Based on this, it is determined whether or not the object to be inspected contains metal.
  • Patent Document 1 describes two discrimination methods using Lissajous waveforms.
  • the first discrimination method an allowable frame surrounding the reference Lissajous waveform is set, and if the Lissajous waveform when passing the inspection object exceeds the allowable frame, it is determined that the inspection object contains a metal piece. To do.
  • the XY coordinates on which the Lissajous waveform is displayed are divided from the first quadrant to the fourth quadrant, and the area on the coordinates of the region surrounded by the Lissajous waveform in each quadrant is obtained. .
  • the calculated area in at least one quadrant is different from the reference area by a threshold value or more, it is determined that the object to be inspected contains a metal piece.
  • an abnormality is not determined unless the area surrounded by the Lissajous waveform changes beyond the threshold value. For this reason, even if the Lissajous waveform is greatly deformed by being convex on one side and concave on the other side in any quadrant, it is determined as normal unless the area exceeds the threshold value. Therefore, it is not possible to improve the detection accuracy such as mixing of metal pieces.
  • the present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a metal inspection apparatus that can detect the mixing of metal into an inspection object with high accuracy using a Lissajous waveform.
  • the present invention relates to a metal detection device provided with a transmission coil to which an alternating excitation signal is applied, a plurality of reception coils, and a transport mechanism that moves the inspection object toward the transmission coil and the reception coil.
  • the data processing unit includes a Lissajous waveform generation unit that draws a Lissajous waveform on a plane coordinate from the first detection signal and the second detection signal that change with the movement of the inspection object, and the plane coordinate
  • a determination line or region setting unit that sets a determination line or determination region on top, and a determination unit that determines that the inspection object is abnormal when the determination line or determination region and the Lissajous waveform share the same coordinate point And is provided.
  • the present invention is characterized in that a determination unit is provided that determines that the inspection object is abnormal when the determination line or the determination region and the Lissajous waveform do not share the same coordinate point. .
  • the coil signal is detected by AC signals whose phases are different from each other by 90 degrees.
  • the present invention can be configured such that the data processing unit is provided with a memory for storing a plurality of the determination lines or the determination areas set for each type of inspection object.
  • an operation unit is provided for setting the determination line or the determination area and storing it in the memory.
  • the determination line or the determination region is determined to be abnormal without sharing the same coordinate point as the reference Lissajous waveform when the inspection object to be determined to be normal is inspected.
  • the coordinate position sharing the same coordinate point as that of the abnormal Lissajous waveform when the object to be inspected is inspected is set.
  • the determination line or the determination region is set to at least one of an inner region surrounded by the reference Lissajous waveform and an outer region outside the reference Lissajous waveform.
  • the determination line or the determination region is set in both the inner region and the outer region.
  • the determination line or the determination region should share the same coordinate point as the reference Lissajous waveform when the inspection object to be determined to be normal is inspected and be determined to be abnormal.
  • the abnormal Lissajous waveform when the inspection object is inspected is set to a coordinate position that does not share the same coordinate point.
  • the abnormal Lissajous waveform is obtained by inspecting a normal inspection object with a metal sample installed.
  • both an abnormal Lissajous waveform using a magnetic metal sample and an abnormal Lissajous waveform using a non-magnetic metal sample are obtained.
  • a plurality of abnormal Lissajous waveforms are obtained by placing metal samples at different positions on a normal inspection object.
  • the metal detection device of the present invention does not share the same coordinate point as the Lissajous waveform when a normal inspection object is passed, and the Lissajous waveform when an abnormal inspection object containing metal is passed.
  • the metal detection device of the present invention can detect a normal inspection object and an abnormal inspection object with high accuracy by providing a determination line or a determination area at a coordinate position sharing the same coordinate point as the reference Lissajous waveform. become able to.
  • Explanatory drawing which shows only the principal part of the metal inspection apparatus of embodiment of this invention, Circuit block diagram of metal inspection equipment, A circuit block diagram showing the configuration of the data processing unit, Explanatory drawing showing the arrangement of the inspection object and the metal sample, An explanatory diagram showing a reference Lissajous waveform and a determination line when a normal inspection object is inspected, Explanatory drawing which shows the setting of a reference Lissajous waveform and a judgment area when inspecting a normal inspection object, An explanatory diagram of an abnormal Lissajous waveform obtained when a metal sample of magnetic metal is placed in the center of a normal inspection object, An explanatory diagram of an abnormal Lissajous waveform obtained when a metal sample of magnetic metal is placed on the front of a normal inspection object, An explanatory diagram of an abnormal Lissajous waveform obtained when a metal sample of a magnetic metal is placed on the back of a normal inspection object, An explanatory diagram of an abnormal Lissajous waveform obtained
  • the metal detection device 1 according to the first embodiment of the present invention shown in FIG.
  • the transport mechanism 2 has an upstream roller 3, a downstream roller 4, and a transport belt 5 hung on both rollers 3 and 4.
  • One of the upstream roller 3 and the downstream roller 4 is a driving roller and the other is a driven roller.
  • the inspection object W is transferred in the direction F by the transport mechanism 2.
  • the transmission coil Ct is opposed above the movement path of the inspection object W.
  • the winding axis of the transmission coil Ct extends in parallel with the conveyance direction (F direction) of the inspection object W.
  • Two receiving coils Cr ⁇ b> 1 and Cr ⁇ b> 2 are provided below the moving path of the inspection object W.
  • the number of turns of the reception coil Cr1 and the reception coil Cr2 is the same.
  • the reception coils Cr1 and Cr2 are arranged at intervals in the transport direction (F direction), and each is opposed to the transmission coil Ct.
  • the winding axes of the two receiving coils Cr1, Cr2 are located on the same line, and the winding axes extend in parallel with the transport direction (F direction).
  • an AC drive source 11 is connected to the transmission coil Ct, and an excitation signal 12 of AC current is given to the transmission coil Ct.
  • the two reception coils Cr1 and Cr2 are connected to each other, and a coil signal 13 is obtained that is a comparison value of induced power induced in the reception coil Cr1 and the reception coil Cr2 by the excitation magnetic field of the transmission coil Ct.
  • a resistor R1 is connected to the upstream receiving coil Cr1, and a resistor R2 is connected to the downstream receiving coil Cr2.
  • the receiving coils Cr1 and Cr2 have the same inductance, and the two resistors R1 and R2 have the same resistance value.
  • the voltage measured by the resistor R1 is applied to the plus terminal of the differential amplifier 14, and the voltage measured by the resistor R2 is applied to the minus terminal of the differential amplifier 14.
  • the winding directions of the receiving coil Cr1 and the receiving coil Cr2 are the same.
  • the induced power induced in the reception coil Cr1 and the induced power induced in the reception coil Cr2 by the excitation magnetic field from the transmission coil Ct The value is the same. Therefore, the input voltage to the plus terminal and the minus terminal of the differential amplifier 14 becomes the same, and the coil signal 13 becomes zero or a predetermined midpoint potential.
  • the differential amplifier 14 obtains a differential output (2 ⁇ E1) obtained by subtracting the voltage decrease measured by the resistor R2 ( ⁇ E1) from the voltage increase measured by the resistor R1 (+ ⁇ E1). This differential output becomes the coil signal 13.
  • the coil signal 13 is an AC signal having the same frequency as that of the excitation signal 12 supplied from the AC drive source 11, but the voltage decrease due to the eddy current loss of the nonmagnetic metal has a phase of 90 with respect to the excitation signal 12.
  • the AC component is delayed.
  • the coil signal 13 By setting a differential value (differential signal), which is a comparison value (comparison signal) between the two receiving coils Cr1 and Cr2, as the coil signal 13, the metal that has entered between the transmitting coil Ct and the receiving coils Cr1 and Cr2 can be obtained. Can be detected. Depending on whether the intervening metal is a magnetic metal or a nonmagnetic metal, the coil signal 13 includes an AC signal having a different phase.
  • the coil signal 13 is given to the first detection unit 15 and the second detection unit 16.
  • Both detection units 15 and 16 are phase detection circuits (synchronous detection circuits).
  • the coil signal 13 is detected by an AC signal having the same phase as the excitation signal 12.
  • the multiplier 15 a multiplies the coil signal 13 with an AC signal having the same phase as the excitation signal 12, and a DC component having a magnitude proportional to the amplitude of the coil signal 13 and 2 of the excitation signal 12.
  • An output obtained by adding the AC signal having the double frequency is obtained.
  • the first detection signal 18 which is the DC component is obtained.
  • the second detector 16 has a multiplier 16a and a low-pass filter 16b.
  • the excitation signal 12 from the AC drive source 11 is delayed by 90 degrees in phase by the phase shift circuit 17, and the second detector 16 detects the coil signal 13 using an AC signal that is 90 degrees out of phase, A detection signal 19 is obtained.
  • the first detection signal 18 is amplified by an amplifier 21, converted to a digital first detection signal 18 a by an A / D converter 22, and given to the data processing unit 30.
  • the second detection signal 19 is also amplified by the amplifier 23, converted to a digital second detection signal 19 a by the A / D converter 24, and supplied to the data processing unit 30.
  • the data processing unit 30 includes a CPU and a memory, and each processing unit indicated by a block in FIG. 3 is achieved by executing software.
  • the coil signals 13 from the receiving coils Cr1 and Cr2 are detected by AC signals having different phases different by 90 degrees, and then the first detection signal 18a and the second detection signal 19a digitized are converted into a data processing unit 30.
  • a vector value is calculated from the first detection signal 18 a and the second detection signal 19 a and is given to the Lissajous waveform generation unit 32.
  • a waveform signal is generated from the vector value and is supplied to the display driver 33.
  • a Lissajous waveform based on the waveform signal is displayed on the display screen 34 a of the display unit 34.
  • FIGS. 5 and 6 when a normal inspection object W not mixed with metal is moving in the F direction at a constant speed between the transmission coil Ct and the two reception coils Cr1, Cr2, A reference Lissajous waveform 41 displayed on the display screen 34a is shown.
  • the reference Lissajous waveform 41 is displayed on the display screen 34 a and stored in the waveform memory 35.
  • the reference Lissajous waveform 41 shown in FIG. 5 and FIG. 6 is obtained when an inspection object W in which ten pieces of roast ham are stacked and vacuum-packed with a transparent film packaging material is inspected.
  • both the contents and the packaging material contain a small amount of magnetic metal component and non-magnetic metal component. Therefore, the intensity and phase of the coil signal 13 change every moment as the inspection object W moves in the F direction.
  • the Lissajous waveform is drawn on the XY plane coordinates.
  • the X axis shows the intensity change of the first detection signal 18a
  • the Y axis shows the intensity change of the second detection signal 19a.
  • the locus where the coordinate point P obtained by the vector calculation of the first detection signal 18a and the second detection signal 19a having different phases changes as the object W moves in the direction F is a Lissajous waveform. is there.
  • the coordinate point P is adjusted so as to be located at the origin O of the XY coordinates. Thereafter, when the inspection object W moves between the transmission coil Ct and the two reception coils Cr1, Cr2, the coordinate point P moves to draw a waveform, and the inspection object W is received by the reception coils Cr1, Cr2. When it is out of the area, the coordinate point P returns to the origin O.
  • the reference Lissajous waveform 41 shown in FIGS. 5 and 6 differs depending on the type of the inspection object W.
  • the inspected object W used in FIG. 5 has a round ham as a content, and has a symmetrical shape in the moving direction (F direction). Therefore, when a normal inspection object W in which no metal foreign matter is mixed is inspected, the reference Lissajous waveform 41 has a rotationally symmetric shape of about 180 degrees around the origin O.
  • the data processing unit 30 is provided with a determination line or region setting unit 36 so that the determination line or region setting unit 36 can be operated from the operation unit 26 provided in the metal detection device 1. It has become.
  • the determination lines 51a, 51b, 51c, and 51d can be set in the XY coordinates as shown in FIG.
  • the determination lines may be collectively indicated by reference numeral 51.
  • the determination line 51 is set at a coordinate position that does not overlap with the reference Lissajous waveform 41 stored in the waveform memory 35.
  • the determination line 51 is set in an inner region surrounded by the reference Lissajous waveform 41 drawn in a loop shape (reference numerals 51a and 51b).
  • the determination line 51 is set outside the region surrounded by the reference Lissajous waveform 41 (reference numerals 51c and 51d).
  • the determination line 51 is set on both the inside and the outside of the region surrounded by the reference Lissajous waveform 41 (reference numerals 51a, 51b, 51c, 51d).
  • the determination line is set by a linear function so as to be drawn linearly on the XY plane coordinates as indicated by reference numerals 51a and 51b.
  • a curve is set by a multi-order function such as a quadratic function.
  • the determination lines 51a, 51b, 51c, and 51d are individually set according to the type of each inspection object W, and the determination lines 51a, 51b, 51c, and 51d corresponding to each of the plurality of types of inspection objects W are drawn. Data is stored in the judgment line or area memory 37.
  • a waveform signal is generated by the Lissajous waveform generation unit 32 and displayed.
  • a Lissajous waveform is drawn on the screen 34a.
  • the determination unit 38 provided in the data processing unit 30, the determination lines 51a, 51b, 51c, 51d stored in the determination line or the area memory 37 are compared with the waveform signal or Lissajous waveform created during the inspection.
  • the same coordinate point is shared by the Lissajous waveform intersecting or touching any of the determination lines 51a, 51b, 51c, and 51d, it is determined that there is a suspicion that the inspection object W contains metal.
  • the screen 34a displays that the inspected object W currently being inspected is abnormal, and also emits a warning sound.
  • the inspection object W to be inspected is from when it enters the reception range of the upstream reception coil Cr1 until it comes out of the reception range of the downstream reception coil Cr2.
  • the coordinate point P changes on the coordinates starting from the origin O.
  • the determination unit 38 tracks the movement of the coordinate point P at this time, and can immediately determine that there is an abnormality when the coordinate point P reaches the same coordinate as one of the determination lines 51a, 51b, 51c, 51d. . By this determination, it is possible to immediately give an abnormality determination before the moving inspection object W is out of the reception range of the reception coils Cr1 and Cr2.
  • the Lissajous waveform is completed between the time when the inspection object W to be inspected enters the reception range of the upstream reception coil Cr1 and the time when it exits the reception range of the downstream reception coil Cr2, and the completed Lissajous waveform is stored in the waveform memory 35. Temporarily save to. Then, the determination unit 38 may determine whether the Lissajous waveform held in the waveform memory 35 intersects or touches any of the determination lines 51a, 51b, 51c, 51d.
  • the determination line or region setting unit 36 is operated by operating the operation unit 26 to set the determination regions 52a, 52b, 52c, and 52d on the XY coordinates. You can also.
  • the determination area may be collectively indicated by reference numeral 52.
  • the determination areas 52a, 52b, 52c, and 52d are set to coordinate positions that do not overlap the reference Lissajous waveform 41 stored in the waveform memory 35.
  • the determination area 52 is set in an inner area surrounded by the reference Lissajous waveform 41 drawn in a loop shape, or is set in an outer area of the reference Lissajous waveform 41.
  • the determination area 52 is set both inside and outside the area surrounded by the reference Lissajous waveform 41.
  • the determination area 52 can be set as a polygon such as a rectangle, a square, or a trapezoid, or can be set as a shape such as a circle or an ellipse.
  • the determination areas 52a, 52b, 52c, and 52d are stored in the determination line or the area memory 37 in the same manner as the determination line 51, and the determination unit 38 determines which Lissajous waveform under examination is one of the determination areas 52a, 52b, 52c, If the same coordinate point is shared by crossing or contacting 52d, it is determined that there is a possibility of containing a metal foreign object.
  • a normal inspection object W (a normal inspection object W in which 10 pieces of roast ham are vacuum-packed with a packaging material) is installed in the transport mechanism 2, and a certain amount is set between the transmission coil Ct and the reception coils Cr1 and Cr2.
  • the reference Lissajous waveform 41 shown in FIGS. 5 and 6 is obtained and stored in the waveform memory 35.
  • a metal sample 55 containing iron powder which is a fine magnetic metal powder, is placed on the central portion (i) in the transport direction of a normal inspection object W and placed on the transport mechanism 2. Install.
  • this inspection object is supplied between the transmission coil Ct and the reception coils Cr1, Cr2, an abnormal Lissajous waveform 42 shown in FIG. 7 is generated.
  • the waveform signal of the abnormal Lissajous waveform 42 is stored in the waveform memory 35.
  • an abnormal Lissajous waveform 43 shown in FIG. 8 is generated, and the metal sample 55 is placed on the rear part (iii) in the conveyance direction of the inspection object. Then, an abnormal Lissajous waveform 44 shown in FIG. 9 is generated.
  • the waveform signals of these abnormal Lissajous waveforms 43 and 44 are stored in the waveform memory 35, respectively.
  • an abnormal Lissajous waveform 45 shown in FIG. 10 is generated.
  • an abnormal Lissajous waveform 46 shown in FIG. 11 is obtained, and when the metal sample 56 is placed on the rear part (iii) of the inspection object W, FIG.
  • the abnormal Lissajous waveforms 45, 46 and 47 are stored in the waveform memory 35.
  • the coordinates at which all the abnormal Lissajous waveforms 42 to 47 intersect or contact each other without intersecting or contacting the reference Lissajous waveform 41 in the determination line or region setting unit 36 are obtained.
  • a determination line 51 is set at the position.
  • the determination area 52 is set.
  • the determination line 51 or the determination region 52 it is preferable to use all of the six types of abnormal Lissajous waveforms 42 to 47, but using only a part of the abnormal Lissajous waveforms 42 to 47,
  • the determination line 51 or the determination area 52 may be set.
  • an abnormal Lissajous waveform 42 obtained by installing a metal sample 55 containing a magnetic metal in the central part (i) and an abnormality obtained by installing a metal sample 56 containing a nonmagnetic metal in the central part (i)
  • the characteristics of the waveforms are greatly different. Accordingly, when the determination line 51 or the determination region 52 is set at a coordinate position where the two abnormal Lissajous waveforms 42 and 45 intersect or touch each other, the other abnormal Lissajous waveforms 43, 44, 46, and 47 are also determined by the determination line 51 or the determination region 52.
  • the region 52 intersects or touches.
  • abnormal Lissajous waveform 43 shown in FIG. 8 obtained by arranging the metal sample 55 in the front part (ii) and the abnormal Lissajous waveform 44 shown in FIG. 9 obtained by arranging in the rear part (iii) are compared. Then, these two waveforms are approximately 180 degrees rotationally symmetric about the origin O. Therefore, if one of the abnormal Lissajous waveforms 43 and 44 is obtained, an appropriate set position of the determination line 51 or the determination region 52 can be predicted. This also applies to the relationship between the abnormal Lissajous waveform 46 shown in FIG. 11 and the abnormal Lissajous waveform 47 shown in FIG.
  • the determination line 51 or the determination area 52 is created by displaying the reference Lissajous waveform 41 and a plurality of abnormal Lissajous waveforms on the display screen 34a, and operating the operation unit 26 to draw the determination line 51 on the XY coordinates.
  • an image of the determination area 52 is created and stored in the determination line or area memory 37.
  • a plurality of determination lines 51 having different lengths and shapes and a plurality of patterns of determination regions 52 having different areas and shapes are stored in the determination line or region memory 37 in advance.
  • the operation unit 26 is operated to select one of the determination line 51 patterns or one of the determination region 52 patterns. , May be pasted on the XY coordinates.
  • the data of the reference Lissajous waveform 41 and the plurality of abnormal Lissajous waveforms 41 are compared by the calculation in the CPU, and the coordinate data of the plurality of abnormal Lissajous waveforms are intersected without intersecting or touching the coordinate data of the reference Lissajous waveform 41.
  • a place to be contacted may be selected, the pattern of the determination line 51 or the determination area 52 may be called from the memory, and automatically allocated and pasted.
  • determination line 51 or the determination area 52 may be used together instead of using either the determination line 51 or the determination area 52.
  • FIG. 13 is an explanatory diagram showing another embodiment of a method for setting the determination line 53 and the determination area 54.
  • the reference Lissajous waveform 41 always intersects or touches, so that the reference Lissajous waveform 41 shares the coordinate point and the abnormal Lissajous waveform does not intersect or touch any other, and the abnormal Lissajous waveform.
  • the determination line 53 and / or the determination area 54 are set in an area that does not share coordinate points. In this case, when the Lissajous waveform obtained when the inspection object W is inspected does not intersect all the determination lines 53 or all the determination areas 54 and is not in contact with each other, it is determined that the object is abnormal.
  • One or more determination lines 53 or determination areas 54 are set.
  • determination line 51 and the determination area 52 shown in FIGS. 5 and 6 may be used together with the determination line 53 and the determination area 54 shown in FIG.
  • an oxygen scavenger is enclosed with the contents such as food as the object to be inspected W
  • a normal Lissajous waveform containing the oxygen scavenger is inspected to obtain a reference Lissajous waveform
  • An abnormal Lissajous waveform may be generated from the inspection object from which the oxygen scavenger has been removed. Thereby, it is possible to detect an abnormal inspection object that does not contain an oxygen scavenger.
  • the metal detection device of the present invention is not limited to the one in which the transmission coil Ct and the reception coils Cr1 and Cr2 are opposed to each other.
  • the receiving coils CR1 and CR2 may be arranged coaxially, and the inspection object W may pass through the coils CT, CR1 and CR2.

Landscapes

  • 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

[Problem] To provide a metal-detection device that can detect test materials including metallic foreign bodies with high precision using Lissajous waveforms. [Solution] In the present invention, a test material is moved to between a transmission coil and two reception coils, a coil signal is obtained that is the comparison value of the electrical power induced in the two reception coils, this coil signal is detected using two alternating-current signals with different phases, and a first detection signal and a second detection signal are obtained. When a normal test material (W) is moved, a reference Lissajous waveform (41) is obtained using the first detection signal and the second detection signal. A plurality of determination lines (51a, 51b, 51c, 51d) are set in regions that do not intersect or come into contact with the reference Lissajous waveform, and if a Lissajous waveform obtained during measurement intersects or comes into contact with any of the determination lines, the test material being measured is determined to be abnormal.

Description

金属検知装置Metal detector
　本発明は、送信コイルと受信コイルを備えた金属検知装置に係り、特にリサージュ波形を使用して高精度な検査結果を得られるようにした金属検知装置に関する。 The present invention relates to a metal detection apparatus including a transmission coil and a reception coil, and more particularly to a metal detection apparatus that can obtain a highly accurate inspection result using a Lissajous waveform.
　以下の特許文献１に記載されているように、従来の金属検知装置は、送信コイルと２つの受信コイルの間に被検査物が供給され、２つの受信コイルの誘起電力の差が出力信号として得られる。第１の同期検波器で、出力信号が送信コイルの励磁信号で検波され、第２の同期検波器で、励磁信号と位相が９０度違う信号で出力信号が検波される。位相の相違する信号で検波された２つの検波出力がリサージュ波形成形部に送られ、被検査物の移動に伴って変化する２つの検波出力によって二次元座標にリサージュ波形が描かれ、その波形に基づいて被検査物に金属が含まれているか否かが判別される。 As described in Patent Document 1 below, in a conventional metal detection device, an object to be inspected is supplied between a transmission coil and two reception coils, and the difference in induced power between the two reception coils is used as an output signal. can get. In the first synchronous detector, the output signal is detected by the excitation signal of the transmission coil, and in the second synchronous detector, the output signal is detected by a signal that is 90 degrees out of phase with the excitation signal. Two detection outputs detected by signals with different phases are sent to the Lissajous waveform shaping unit, and a Lissajous waveform is drawn on the two-dimensional coordinates by the two detection outputs that change with the movement of the inspection object. Based on this, it is determined whether or not the object to be inspected contains metal.
　特許文献１にはリサージュ波形を用いた２つの判別方法が記載されている。第１の判別方法は、基準となるリサージュ波形を囲む許容枠を設定し、被検査物を通過させたときのリサージュ波形が許容枠を超えたら被検査物に金属片が含まれていると判別する。 Patent Document 1 describes two discrimination methods using Lissajous waveforms. In the first discrimination method, an allowable frame surrounding the reference Lissajous waveform is set, and if the Lissajous waveform when passing the inspection object exceeds the allowable frame, it is determined that the inspection object contains a metal piece. To do.
　第２の判別方法は、リサージュ波形が表示されているＸ－Ｙ座標を、第１象限から第４象限に区切り、それぞれの象限においてリサージュ波形で囲まれている領域の座標上での面積を求める。そして少なくとも１つの象限での算出面積が、基準となる面積としきい値以上に相違していたときに、被検査物に金属片が含まれていると判別する。 In the second discrimination method, the XY coordinates on which the Lissajous waveform is displayed are divided from the first quadrant to the fourth quadrant, and the area on the coordinates of the region surrounded by the Lissajous waveform in each quadrant is obtained. . When the calculated area in at least one quadrant is different from the reference area by a threshold value or more, it is determined that the object to be inspected contains a metal piece.
特開２００１－９１６６２号公報JP 2001-91662 A
　特許文献１にも記載されているように、第１の判別方法では、検査時に得られたリサージュ波形が許容枠を超えない限り異常と判別されない。そのため、被検査物に金属が混入して、リサージュ波形が許容枠を超えない範囲で大きく変形しても、これを判別することができない。 As described in Patent Document 1, in the first determination method, it is not determined as abnormal unless the Lissajous waveform obtained at the time of inspection exceeds the allowable frame. Therefore, even if a metal is mixed into the object to be inspected and the Lissajous waveform is largely deformed within a range not exceeding the allowable frame, this cannot be determined.
　第２の判別方法では、リサージュ波形で囲まれた面積がしきい値を超えて変化しないかぎり異常と判別されない。そのため、いずれかの象限でリサージュ波形が一方の側で凸形状となり他方の側へ凹形状になるなどして大きく変形したとしても、面積がしきい値を超えない限り正常と判別されてしまう。したがって、金属片の混入などの検知精度を高めることができない。 In the second determination method, an abnormality is not determined unless the area surrounded by the Lissajous waveform changes beyond the threshold value. For this reason, even if the Lissajous waveform is greatly deformed by being convex on one side and concave on the other side in any quadrant, it is determined as normal unless the area exceeds the threshold value. Therefore, it is not possible to improve the detection accuracy such as mixing of metal pieces.
　本発明は上記従来の課題を解決するものであり、リサージュ波形を使用して被検査物への金属の混入を高精度に検出できるようにした金属検査装置を提供することを目的としている。 The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a metal inspection apparatus that can detect the mixing of metal into an inspection object with high accuracy using a Lissajous waveform.
　本発明は、交流の励磁信号が与えられる送信コイルと、複数の受信コイルと、前記送信コイルと前記受信コイルへ向けて被検査物を移動させる搬送機構とが設けられた金属検知装置において、
　複数の前記受信コイルの誘起電力の比較値から求められるコイル信号を検波する第１の検波部と、前記コイル信号を、前記励磁信号と位相が相違する交流信号で検波する第２の検波部と、前記第１の検波部で得られた第１の検知信号と前記第２の検波部で得られた第２の検知信号とを処理するデータ処理部とが設けられており、
　前記データ処理部には、前記被検査物の移動に伴って変化する前記第１の検知信号と前記第２の検知信号とから平面座標上にリサージュ波形を描くリサージュ波形生成部と、前記平面座標上に判定ラインまたは判定領域を設定する判定ラインまたは領域設定部と、前記判定ラインまたは前記判定領域と前記リサージュ波形とが同じ座標点を共有したときに、被検査物を異常と判定する判定部と、が設けられていることを特徴とするものである。 The present invention relates to a metal detection device provided with a transmission coil to which an alternating excitation signal is applied, a plurality of reception coils, and a transport mechanism that moves the inspection object toward the transmission coil and the reception coil.
A first detector for detecting a coil signal obtained from a comparison value of induced electric powers of the plurality of receiving coils; and a second detector for detecting the coil signal with an AC signal having a phase different from that of the excitation signal. A data processing unit for processing the first detection signal obtained by the first detection unit and the second detection signal obtained by the second detection unit;
The data processing unit includes a Lissajous waveform generation unit that draws a Lissajous waveform on a plane coordinate from the first detection signal and the second detection signal that change with the movement of the inspection object, and the plane coordinate A determination line or region setting unit that sets a determination line or determination region on top, and a determination unit that determines that the inspection object is abnormal when the determination line or determination region and the Lissajous waveform share the same coordinate point And is provided.
　あるいは、本発明は、前記判定ラインまたは前記判定領域と前記リサージュ波形が同じ座標点を共有しないときに、被検査物を異常と判定する判定部が設けられていることを特徴とするものである。 Alternatively, the present invention is characterized in that a determination unit is provided that determines that the inspection object is abnormal when the determination line or the determination region and the Lissajous waveform do not share the same coordinate point. .
　例えば、前記第１の検波部と前記第２の検波部とでは、位相が互いに９０度相違する交流信号で前記コイル信号が検波されるものである。 For example, in the first detection unit and the second detection unit, the coil signal is detected by AC signals whose phases are different from each other by 90 degrees.
　本発明は、前記データ処理部に、被検査物の種別ごとに設定される前記判定ラインまたは前記判定領域を複数記憶するメモリが設けられているものとして構成できる。 The present invention can be configured such that the data processing unit is provided with a memory for storing a plurality of the determination lines or the determination areas set for each type of inspection object.
　また、前記判定ラインまたは前記判定領域を設定して前記メモリに記憶させる操作部が設けられている。 Further, an operation unit is provided for setting the determination line or the determination area and storing it in the memory.
　本発明の金属検知装置では、前記判定ラインまたは前記判定領域は、正常と判定されるべき被検査物を検査したときの基準リサージュ波形と同じ座標点を共有することがなく、異常と判定されるべき被検査物を検査したときの異常リサージュ波形と同じ座標点を共有する座標位置に設定される。 In the metal detector of the present invention, the determination line or the determination region is determined to be abnormal without sharing the same coordinate point as the reference Lissajous waveform when the inspection object to be determined to be normal is inspected. The coordinate position sharing the same coordinate point as that of the abnormal Lissajous waveform when the object to be inspected is inspected is set.
　この場合に、前記判定ラインまたは前記判定領域は、前記基準リサージュ波形で囲まれる内側領域と、前記基準リサージュ波形の外側の外側領域の少なくとも一方に設定される。ただし、前記判定ラインまたは前記判定領域は、前記内側領域と、前記外側領域の双方に設定されることが好ましい。 In this case, the determination line or the determination region is set to at least one of an inner region surrounded by the reference Lissajous waveform and an outer region outside the reference Lissajous waveform. However, it is preferable that the determination line or the determination region is set in both the inner region and the outer region.
　あるいは、本発明の金属検知装置では、前記判定ラインまたは前記判定領域は、正常と判定されるべき被検査物を検査したときの基準リサージュ波形と同じ座標点を共有し、異常と判定されるべき被検査物を検査したときの異常リサージュ波形が同じ座標点を共有しない座標位置に設定される。 Alternatively, in the metal detection device of the present invention, the determination line or the determination region should share the same coordinate point as the reference Lissajous waveform when the inspection object to be determined to be normal is inspected and be determined to be abnormal. The abnormal Lissajous waveform when the inspection object is inspected is set to a coordinate position that does not share the same coordinate point.
　本発では、異常リサージュ波形は、正常な被検査物に金属試料を設置したものを検査することで得られる。 In the present invention, the abnormal Lissajous waveform is obtained by inspecting a normal inspection object with a metal sample installed.
　例えば、磁性金属の金属試料を用いた異常リサージュ波形と、非磁性金属の金属試料を用いた異常リサージュ波形の双方を得る。または、正常な被検査物の異なる位置に金属試料を配置して複数の異常リサージュ波形を得る。 For example, both an abnormal Lissajous waveform using a magnetic metal sample and an abnormal Lissajous waveform using a non-magnetic metal sample are obtained. Alternatively, a plurality of abnormal Lissajous waveforms are obtained by placing metal samples at different positions on a normal inspection object.
　本発明の金属検知装置は、正常な被検査物を通過させたときのリサージュ波形と同じ座標点を共有することがなく、金属を含んだ異常な被検査物を通過させたときのリサージュ波形と同じ座標点を共有する座標位置に判定ラインまたは判定領域が設定されることにより、金属を含んだ被検査物を判別する精度を高めることができる。 The metal detection device of the present invention does not share the same coordinate point as the Lissajous waveform when a normal inspection object is passed, and the Lissajous waveform when an abnormal inspection object containing metal is passed By setting a determination line or a determination region at a coordinate position sharing the same coordinate point, it is possible to improve the accuracy of determining an inspection object including metal.
　特に、判定ラインまたは判定領域を、基準となるリサージュ波形の内側と外側の双方に複数か所設定することで、磁性金属を含んだ被検査物や非磁性金属を含んだ被検査物を精度よく判別することが可能になる。 In particular, by setting multiple judgment lines or judgment areas on both the inside and outside of the reference Lissajous waveform, it is possible to accurately inspect objects containing magnetic metals and objects containing non-magnetic metals. It becomes possible to determine.
　または、本発明の金属検知装置は、基準リサージュ波形と同じ座標点を共有する座標位置に判定ラインまたは判定領域を設けることで、正常な被検査物と、異常な被検査物を高精度に検知できるようになる。 Alternatively, the metal detection device of the present invention can detect a normal inspection object and an abnormal inspection object with high accuracy by providing a determination line or a determination area at a coordinate position sharing the same coordinate point as the reference Lissajous waveform. become able to.
本発明の実施の形態の金属検査装置の主要部のみを示す説明図、Explanatory drawing which shows only the principal part of the metal inspection apparatus of embodiment of this invention, 金属検査装置の回路ブロック図、Circuit block diagram of metal inspection equipment, データ処理部の構成を示す回路ブロック図、A circuit block diagram showing the configuration of the data processing unit, 被検査物と金属試料の配置を示す説明図、Explanatory drawing showing the arrangement of the inspection object and the metal sample, 正常な被検査物を検査したときの基準リサージュ波形と判定ラインを示す説明図、An explanatory diagram showing a reference Lissajous waveform and a determination line when a normal inspection object is inspected, 正常な被検査物を検査したときの基準リサージュ波形と判定領域の設定を示す説明図、Explanatory drawing which shows the setting of a reference Lissajous waveform and a judgment area when inspecting a normal inspection object, 正常な被検査物に磁性金属の金属試料を中央に設置したときに得られる異常リサージュ波形の説明図、An explanatory diagram of an abnormal Lissajous waveform obtained when a metal sample of magnetic metal is placed in the center of a normal inspection object, 正常な被検査物に磁性金属の金属試料を前部に設置したときに得られる異常リサージュ波形の説明図、An explanatory diagram of an abnormal Lissajous waveform obtained when a metal sample of magnetic metal is placed on the front of a normal inspection object, 正常な被検査物に磁性金属の金属試料を後部に設置したときに得られる異常リサージュ波形の説明図、An explanatory diagram of an abnormal Lissajous waveform obtained when a metal sample of a magnetic metal is placed on the back of a normal inspection object, 正常な被検査物に非磁性金属の金属試料を中央に設置したときに得られる異常リサージュ波形の説明図、An explanatory diagram of an abnormal Lissajous waveform obtained when a non-magnetic metal sample is placed in the center of a normal inspection object, 正常な被検査物に非磁性金属の金属試料を前部に設置したときに得られる異常リサージュ波形の説明図、An explanatory diagram of an abnormal Lissajous waveform obtained when a non-magnetic metal sample is placed on the front of a normal inspection object, 正常な被検査物に非磁性金属の金属試料を前部に設置したときに得られる異常リサージュ波形の説明図、An explanatory diagram of an abnormal Lissajous waveform obtained when a non-magnetic metal sample is placed on the front of a normal inspection object, 判定ラインと判定領域の他の設定例を示す説明図、Explanatory drawing which shows the other example of a setting of a judgment line and a judgment area, 他の実施の形態の金属検知装置の主要部を示す説明図、Explanatory drawing which shows the principal part of the metal detection apparatus of other embodiment,
　図１に示す本発明の第１の実施の形態の金属検知装置１は、搬送機構２を有している。搬送機構２は、上流側ローラ３と下流側ローラ４ならびに両ローラ３，４に掛けられた搬送ベルト５を有している。上流側ローラ３と下流側ローラ４の一方が駆動ローラで他方が従動ローラである。被検査物Ｗは搬送機構２によってＦ方向へ移送される。 The metal detection device 1 according to the first embodiment of the present invention shown in FIG. The transport mechanism 2 has an upstream roller 3, a downstream roller 4, and a transport belt 5 hung on both rollers 3 and 4. One of the upstream roller 3 and the downstream roller 4 is a driving roller and the other is a driven roller. The inspection object W is transferred in the direction F by the transport mechanism 2.
　被検査物Ｗの移動経路の上方に送信コイルＣｔが対向している。送信コイルＣｔの巻き軸は、被検査物Ｗの搬送方向（Ｆ方向）と平行に延びている。被検査物Ｗの移動経路の下側に２個の受信コイルＣｒ１，Ｃｒ２が設けられている。受信コイルＣｒ１と受信コイルＣｒ２の巻き回数は同じである。受信コイルＣｒ１，Ｃｒ２は搬送方向（Ｆ方向）に間隔を空けて配置され、それぞれが送信コイルＣｔに対向している。２つの受信コイルＣｒ１，Ｃｒ２の巻き軸は同一線上に位置し、巻き軸は搬送方向（Ｆ方向）と平行に延びている。 The transmission coil Ct is opposed above the movement path of the inspection object W. The winding axis of the transmission coil Ct extends in parallel with the conveyance direction (F direction) of the inspection object W. Two receiving coils Cr <b> 1 and Cr <b> 2 are provided below the moving path of the inspection object W. The number of turns of the reception coil Cr1 and the reception coil Cr2 is the same. The reception coils Cr1 and Cr2 are arranged at intervals in the transport direction (F direction), and each is opposed to the transmission coil Ct. The winding axes of the two receiving coils Cr1, Cr2 are located on the same line, and the winding axes extend in parallel with the transport direction (F direction).
　図２に示すように、送信コイルＣｔに交流駆動源１１が接続されており、送信コイルＣｔに交流電流の励磁信号１２が与えられる。 As shown in FIG. 2, an AC drive source 11 is connected to the transmission coil Ct, and an excitation signal 12 of AC current is given to the transmission coil Ct.
　２つの受信コイルＣｒ１，Ｃｒ２は互いに接続されており、送信コイルＣｔの励起磁界によって受信コイルＣｒ１と受信コイルＣｒ２に誘導される誘起電力の比較値となるコイル信号１３が得られる。上流の受信コイルＣｒ１に抵抗Ｒ１が接続され、下流の受信コイルＣｒ２に抵抗Ｒ２が接続されている。受信コイルＣｒ１，Ｃｒ２はインダクタンスが同じであり、２つの抵抗Ｒ１，Ｒ２は抵抗値が同じである。抵抗Ｒ１で測定される電圧は差動アンプ１４のプラス端子に与えられ、抵抗Ｒ２で測定される電圧は差動アンプ１４のマイナス端子に与えられる。 The two reception coils Cr1 and Cr2 are connected to each other, and a coil signal 13 is obtained that is a comparison value of induced power induced in the reception coil Cr1 and the reception coil Cr2 by the excitation magnetic field of the transmission coil Ct. A resistor R1 is connected to the upstream receiving coil Cr1, and a resistor R2 is connected to the downstream receiving coil Cr2. The receiving coils Cr1 and Cr2 have the same inductance, and the two resistors R1 and R2 have the same resistance value. The voltage measured by the resistor R1 is applied to the plus terminal of the differential amplifier 14, and the voltage measured by the resistor R2 is applied to the minus terminal of the differential amplifier 14.
　図２に示す回路では、受信コイルＣｒ１と受信コイルＣｒ２の巻き方向が同じである。送信コイルＣｔと受信コイルＣｒ１，Ｃｒ２との間に何も存在していないときは、送信コイルＣｔからの励起磁界によって受信コイルＣｒ１に誘導される誘起電力と受信コイルＣｒ２に誘導される誘起電力の値が同じである。よって、差動アンプ１４のプラス端子とマイナス端子への入力電圧が同じになり、コイル信号１３はゼロまたは所定の中点電位となる。 In the circuit shown in FIG. 2, the winding directions of the receiving coil Cr1 and the receiving coil Cr2 are the same. When nothing exists between the transmission coil Ct and the reception coils Cr1 and Cr2, the induced power induced in the reception coil Cr1 and the induced power induced in the reception coil Cr2 by the excitation magnetic field from the transmission coil Ct. The value is the same. Therefore, the input voltage to the plus terminal and the minus terminal of the differential amplifier 14 becomes the same, and the coil signal 13 becomes zero or a predetermined midpoint potential.
　送信コイルＣｔと上流の受信コイルＣｒ１との間に磁性金属が侵入すると、送信コイルＣｔからの励起磁界が、磁性金属に引き付けられて受信コイルＣｒ１側へ多く誘導されるため、抵抗Ｒ１側の電圧が増加し、抵抗Ｒ２側の電圧が低下する。差動アンプ１４からは、抵抗Ｒ１で測定される電圧の増加分（＋ΔＥ１）に、抵抗Ｒ２で測定される電圧の減少分（－ΔＥ１）が減算された差動出力（２ΔＥ１）が得られ、この差動出力がコイル信号１３となる。 When a magnetic metal enters between the transmission coil Ct and the upstream reception coil Cr1, the excitation magnetic field from the transmission coil Ct is attracted to the magnetic metal and induced to the reception coil Cr1 side. Increases and the voltage on the resistor R2 side decreases. The differential amplifier 14 obtains a differential output (2ΔE1) obtained by subtracting the voltage decrease measured by the resistor R2 (−ΔE1) from the voltage increase measured by the resistor R1 (+ ΔE1). This differential output becomes the coil signal 13.
　磁性金属が、送信コイルＣｔと下流の受信コイルＣｒ２との間へ移動すると、抵抗Ｒ２で測定される電圧の増加分（ΔＥ２）が、抵抗Ｒ１で測定される電圧の減少分（－ΔＥ２）で減算され、コイル信号１３が（－ΔＥ２）となる。 When the magnetic metal moves between the transmission coil Ct and the downstream reception coil Cr2, the increase in voltage (ΔE2) measured by the resistor R2 is the decrease in voltage (−ΔE2) measured by the resistor R1. Subtraction is performed, and the coil signal 13 becomes (−ΔE2).
　送信コイルＣｔと上流の受信コイルＣｒ１との間に非磁性金属が侵入すると、受信コイルＣｒ１に与えられるべき励起磁界の一部が非磁性金属内で渦電流損として消費されるため、受信コイルＣｒ１の励起電力が低下し、抵抗Ｒ１で測定される電圧の減少分が（－δＥ）となる。非磁性金属が、下流の受信コイルＣｒ２と対向する位置に移動すると、抵抗Ｒ２で測定される電圧が（－δＥ）だけ減少する。 When a nonmagnetic metal enters between the transmission coil Ct and the upstream reception coil Cr1, a part of the excitation magnetic field to be applied to the reception coil Cr1 is consumed as eddy current loss in the nonmagnetic metal, so that the reception coil Cr1 The excitation power of the voltage decreases, and the decrease in voltage measured by the resistor R1 becomes (−δE). When the nonmagnetic metal moves to a position facing the downstream receiving coil Cr2, the voltage measured by the resistor R2 decreases by (−δE).
　コイル信号１３は、交流駆動源１１から与えられる励磁信号１２と同じ周波数の交流信号であるが、非磁性金属の渦電流損に起因する電圧の減少分は、励磁信号１２に対して位相が９０度遅れた交流成分となる。 The coil signal 13 is an AC signal having the same frequency as that of the excitation signal 12 supplied from the AC drive source 11, but the voltage decrease due to the eddy current loss of the nonmagnetic metal has a phase of 90 with respect to the excitation signal 12. The AC component is delayed.
　２つの受信コイルＣｒ１，Ｃｒ２の比較値（比較信号）である差動値（差動信号）をコイル信号１３とすることにより、送信コイルＣｔと受信コイルＣｒ１，Ｃｒ２との間に入り込んだ金属を検知できる。そして、介入した金属が磁性金属か非磁性金属かにより、コイル信号１３には位相が相違する交流信号が含まれることになる。 By setting a differential value (differential signal), which is a comparison value (comparison signal) between the two receiving coils Cr1 and Cr2, as the coil signal 13, the metal that has entered between the transmitting coil Ct and the receiving coils Cr1 and Cr2 can be obtained. Can be detected. Depending on whether the intervening metal is a magnetic metal or a nonmagnetic metal, the coil signal 13 includes an AC signal having a different phase.
　なお、差動アンプ１４による差動値ではなく、加算アンプなどによる加算値（加算信号）を使用する場合には、上流の受信コイルＣｒ１と下流の受信コイルＣｒ２の巻き方向は互いに逆向きとなる。 When an addition value (addition signal) by an addition amplifier or the like is used instead of the differential value by the differential amplifier 14, the winding directions of the upstream reception coil Cr1 and the downstream reception coil Cr2 are opposite to each other. .
　図２に示すように、コイル信号１３は第１の検波部１５と第２の検波部１６へ与えられる。両検波部１５，１６は位相検波回路（同期検波回路）である。第１の検波部１５では、コイル信号１３が励磁信号１２と同じ位相の交流信号で検波される。第１の検波部１５では、掛け算器１５ａにおいて、コイル信号１３が励磁信号１２と同じ位相の交流信号と掛け合わされて、コイル信号１３の振幅に比例した大きさの直流成分と励磁信号１２の２倍の周波数の交流信号とが加算された出力が得られる、この信号をローパスフィルタ１５ｂに通過させることで、前記直流成分である第１の検知信号１８が得られる。 As shown in FIG. 2, the coil signal 13 is given to the first detection unit 15 and the second detection unit 16. Both detection units 15 and 16 are phase detection circuits (synchronous detection circuits). In the first detector 15, the coil signal 13 is detected by an AC signal having the same phase as the excitation signal 12. In the first detection unit 15, the multiplier 15 a multiplies the coil signal 13 with an AC signal having the same phase as the excitation signal 12, and a DC component having a magnitude proportional to the amplitude of the coil signal 13 and 2 of the excitation signal 12. An output obtained by adding the AC signal having the double frequency is obtained. By passing this signal through the low-pass filter 15b, the first detection signal 18 which is the DC component is obtained.
　第２の検波部１６も同様に掛け算器１６ａとローパスフィルタ１６ｂを有している。交流駆動源１１からの励磁信号１２は移相回路１７によって位相が９０度遅らせられ、第２の検波部１６では、コイル信号１３が９０度位相がずれた交流信号で検波されて、第２の検知信号１９が得られる。 Similarly, the second detector 16 has a multiplier 16a and a low-pass filter 16b. The excitation signal 12 from the AC drive source 11 is delayed by 90 degrees in phase by the phase shift circuit 17, and the second detector 16 detects the coil signal 13 using an AC signal that is 90 degrees out of phase, A detection signal 19 is obtained.
　図２に示すように、第１の検知信号１８は増幅器２１で増幅され、Ａ／Ｄ変換器２２においてディジタルの第１の検知信号１８ａに変換されてデータ処理部３０に与えられる。第２の検知信号１９も増幅器２３で増幅され、Ａ／Ｄ変換器２４でディジタルの第２の検知信号１９ａに変換されてデータ処理部３０に与えられる。 As shown in FIG. 2, the first detection signal 18 is amplified by an amplifier 21, converted to a digital first detection signal 18 a by an A / D converter 22, and given to the data processing unit 30. The second detection signal 19 is also amplified by the amplifier 23, converted to a digital second detection signal 19 a by the A / D converter 24, and supplied to the data processing unit 30.
　データ処理部３０は、ＣＰＵとメモリなどで構成されており、図３においてブロックで示す各処理部は、ソフトウエアを実行することで達成される。 The data processing unit 30 includes a CPU and a memory, and each processing unit indicated by a block in FIG. 3 is achieved by executing software.
　受信コイルＣｒ１，Ｃｒ２からのコイル信号１３を、９０度相違する異なる位相の交流信号で検波し、その後にディジタル化された第１の検知信号１８ａと第２の検知信号１９ａは、データ処理部３０の演算部３１に与えられる。演算部３１では、第１の検知信号１８ａと第２の検知信号１９ａからベクトル値が演算され、リサージュ波形生成部３２に与えられる。リサージュ波形生成部３２では、前記ベクトル値から波形信号が生成され、これが表示ドライバ３３に与えられる。表示部３４の表示画面３４ａには、前記波形信号に基づくリサージュ波形が表示される。 The coil signals 13 from the receiving coils Cr1 and Cr2 are detected by AC signals having different phases different by 90 degrees, and then the first detection signal 18a and the second detection signal 19a digitized are converted into a data processing unit 30. To the arithmetic unit 31. In the calculation unit 31, a vector value is calculated from the first detection signal 18 a and the second detection signal 19 a and is given to the Lissajous waveform generation unit 32. In the Lissajous waveform generation unit 32, a waveform signal is generated from the vector value and is supplied to the display driver 33. A Lissajous waveform based on the waveform signal is displayed on the display screen 34 a of the display unit 34.
　図５と図６には、金属が混入されていない正常な被検査物Ｗが、送信コイルＣｔと２つの受信コイルＣｒ１，Ｃｒ２の間で一定の速度でＦ方向へ移動しているときに、表示画面３４ａに表示される基準リサージュ波形４１が示されている。基準リサージュ波形４１は、表示画面３４ａに表示されるとともに波形メモリ３５に記憶される。 In FIGS. 5 and 6, when a normal inspection object W not mixed with metal is moving in the F direction at a constant speed between the transmission coil Ct and the two reception coils Cr1, Cr2, A reference Lissajous waveform 41 displayed on the display screen 34a is shown. The reference Lissajous waveform 41 is displayed on the display screen 34 a and stored in the waveform memory 35.
　図５と図６に示す基準リサージュ波形４１は、１０枚のロースハムが重ねられ透明フィルムの包装材で真空包装された被検査物Ｗを検査したときに得られたものである。被検査物Ｗでは、内容物と包装材の双方に、微量な磁性金属成分や非磁性金属成分が含まれている。そのため、コイル信号１３の強度と位相は、被検査物ＷがＦ方向へ移動するのにしたがって刻々と変化する。 The reference Lissajous waveform 41 shown in FIG. 5 and FIG. 6 is obtained when an inspection object W in which ten pieces of roast ham are stacked and vacuum-packed with a transparent film packaging material is inspected. In the inspected object W, both the contents and the packaging material contain a small amount of magnetic metal component and non-magnetic metal component. Therefore, the intensity and phase of the coil signal 13 change every moment as the inspection object W moves in the F direction.
　図５と図６などに示すように、リサージュ波形は、Ｘ－Ｙ平面座標上に描かれる。Ｘ軸は第１の検知信号１８ａの強度変化を示し、Ｙ軸は第２の検知信号１９ａの強度変化を示している。互いに位相が相違する第１の検知信号１８ａと第２の検知信号１９ａのベクトル演算で得られた座標点Ｐが、被検査物ＷのＦ方向への移動に伴って変化する軌跡がリサージュ波形である。 As shown in FIGS. 5 and 6, etc., the Lissajous waveform is drawn on the XY plane coordinates. The X axis shows the intensity change of the first detection signal 18a, and the Y axis shows the intensity change of the second detection signal 19a. The locus where the coordinate point P obtained by the vector calculation of the first detection signal 18a and the second detection signal 19a having different phases changes as the object W moves in the direction F is a Lissajous waveform. is there.
　被検査物Ｗが供給されていないときに、座標点ＰがＸ－Ｙ座標の原点Ｏに位置するように調整される。その後、被検査物Ｗが送信コイルＣｔと２つの受信コイルＣｒ１，Ｃｒ２の間を等速度で移動すると、座標点Ｐが移動して波形を描き、被検査物Ｗが受信コイルＣｒ１，Ｃｒ２による受信領域から外れると、座標点Ｐが原点Ｏに復帰する。 When the inspection object W is not supplied, the coordinate point P is adjusted so as to be located at the origin O of the XY coordinates. Thereafter, when the inspection object W moves between the transmission coil Ct and the two reception coils Cr1, Cr2, the coordinate point P moves to draw a waveform, and the inspection object W is received by the reception coils Cr1, Cr2. When it is out of the area, the coordinate point P returns to the origin O.
　図５と図６に示す基準リサージュ波形４１は、被検査物Ｗの種類によって相違する。図５で使用した被検査物Ｗは丸いハムを内容物とするもので、移動方向（Ｆ方向）において対称形状である。そのため、内部に金属の異物が混入していない正常な被検査物Ｗを検査すると、基準リサージュ波形４１は、原点Ｏを中心としてほぼ１８０度の回転対称形状となる。 The reference Lissajous waveform 41 shown in FIGS. 5 and 6 differs depending on the type of the inspection object W. The inspected object W used in FIG. 5 has a round ham as a content, and has a symmetrical shape in the moving direction (F direction). Therefore, when a normal inspection object W in which no metal foreign matter is mixed is inspected, the reference Lissajous waveform 41 has a rotationally symmetric shape of about 180 degrees around the origin O.
　次に、図５と図６に示す基準リサージュ波形４１を基本として、金属が混入している異常な被検査物Ｗを判別するための方法を説明する。 Next, based on the reference Lissajous waveform 41 shown in FIGS. 5 and 6, a method for discriminating an abnormal inspection object W mixed with metal will be described.
　図３に示すように、データ処理部３０には、判定ラインまたは領域設定部３６が設けられ、金属検知装置１に装備された操作部２６から、判定ラインまたは領域設定部３６を操作できるようになっている。操作部２６を操作し、判定ラインまたは領域設定部３６を動作させることによって、図５に示すように、Ｘ－Ｙ座標に判定ライン５１ａ，５１ｂ，５１ｃ，５１ｄを設定することができる。以下では、判定ラインを総称して符号５１で示すことがある。 As shown in FIG. 3, the data processing unit 30 is provided with a determination line or region setting unit 36 so that the determination line or region setting unit 36 can be operated from the operation unit 26 provided in the metal detection device 1. It has become. By operating the operation unit 26 and operating the determination line or region setting unit 36, the determination lines 51a, 51b, 51c, and 51d can be set in the XY coordinates as shown in FIG. Hereinafter, the determination lines may be collectively indicated by reference numeral 51.
　判定ライン５１は、波形メモリ３５に記憶されている基準リサージュ波形４１と重ならない座標位置に設定される。判定ライン５１は、ループ形状に描かれる基準リサージュ波形４１で囲まれた内側の領域に設定される（符号５１ａ，５１ｂ）。または、判定ライン５１は基準リサージュ波形４１で囲まれた領域の外側に設定される（符号５１ｃ，５１ｄ）。好ましくは、判定ライン５１は、基準リサージュ波形４１で囲まれた領域の内側と外側の双方に設定される（符号５１ａ，５１ｂ，５１ｃ，５１ｄ）。 The determination line 51 is set at a coordinate position that does not overlap with the reference Lissajous waveform 41 stored in the waveform memory 35. The determination line 51 is set in an inner region surrounded by the reference Lissajous waveform 41 drawn in a loop shape ( reference numerals 51a and 51b). Alternatively, the determination line 51 is set outside the region surrounded by the reference Lissajous waveform 41 ( reference numerals 51c and 51d). Preferably, the determination line 51 is set on both the inside and the outside of the region surrounded by the reference Lissajous waveform 41 ( reference numerals 51a, 51b, 51c, 51d).
　判定ラインは、符号５１ａ，５１ｂ、で示すようにＸ－Ｙ平面座標上で直線的に描かれるように一次関数で設定される。あるいは、符号５１ｃ，５１ｄで示すように、二次関数などの多次関数で曲線として設定される。判定ライン５１ａ，５１ｂ，５１ｃ，５１ｄは、個々の被検査物Ｗの種類に応じて個別に設定され、複数種類の被検査物Ｗのそれぞれに対応する判定ライン５１ａ，５１ｂ，５１ｃ，５１ｄを描くデータが、判定ラインまたは領域メモリ３７に記憶されている。 The determination line is set by a linear function so as to be drawn linearly on the XY plane coordinates as indicated by reference numerals 51a and 51b. Alternatively, as indicated by reference numerals 51c and 51d, a curve is set by a multi-order function such as a quadratic function. The determination lines 51a, 51b, 51c, and 51d are individually set according to the type of each inspection object W, and the determination lines 51a, 51b, 51c, and 51d corresponding to each of the plurality of types of inspection objects W are drawn. Data is stored in the judgment line or area memory 37.
　被検査物Ｗの検査を行うときは、それぞれの被検査物Ｗが送信コイルＣｔと受信コイルＣｒ１，Ｃｒ２との間に供給される毎に、リサージュ波形生成部３２で波形信号が生成され、表示画面３４ａにリサージュ波形が描かれる。データ処理部３０に設けられた判定部３８では、判定ラインまたは領域メモリ３７に記憶されている判定ライン５１ａ，５１ｂ，５１ｃ，５１ｄと、検査中に作成される波形信号またはリサージュ波形とが比較され、リサージュ波形が判定ライン５１ａ，５１ｂ，５１ｃ，５１ｄのいずれかと交差しまたは接することで同じ座標点を共有したときに、被検査物Ｗに金属が含まれている疑いがあると判別し、表示画面３４ａに現在検査中の被検査物Ｗが異常であることを表示し、併せて警告音などを発する。 When the inspection object W is inspected, each time the inspection object W is supplied between the transmission coil Ct and the reception coils Cr1, Cr2, a waveform signal is generated by the Lissajous waveform generation unit 32 and displayed. A Lissajous waveform is drawn on the screen 34a. In the determination unit 38 provided in the data processing unit 30, the determination lines 51a, 51b, 51c, 51d stored in the determination line or the area memory 37 are compared with the waveform signal or Lissajous waveform created during the inspection. When the same coordinate point is shared by the Lissajous waveform intersecting or touching any of the determination lines 51a, 51b, 51c, and 51d, it is determined that there is a suspicion that the inspection object W contains metal. The screen 34a displays that the inspected object W currently being inspected is abnormal, and also emits a warning sound.
　リサージュ波形生成部３２で生成される波形信号では、検査すべき被検査物Ｗが、上流の受信コイルＣｒ１の受信範囲に入ってから下流の受信コイルＣｒ２の受信範囲から出るまでの間、図５に示すように、座標点Ｐが原点Ｏを始点として座標上で変化していく。判定部３８は、このときの座標点Ｐの移動を追跡し、座標点Ｐがいずれかの判定ライン５１ａ，５１ｂ，５１ｃ，５１ｄと同じ座標に至ったときに即座に異常と判断することができる。この判定により、移動中の被検査物Ｗが受信コイルＣｒ１，Ｃｒ２の受信範囲から外れる前に、直ちに異常判定を与えることができる。 In the waveform signal generated by the Lissajous waveform generation unit 32, the inspection object W to be inspected is from when it enters the reception range of the upstream reception coil Cr1 until it comes out of the reception range of the downstream reception coil Cr2. As shown, the coordinate point P changes on the coordinates starting from the origin O. The determination unit 38 tracks the movement of the coordinate point P at this time, and can immediately determine that there is an abnormality when the coordinate point P reaches the same coordinate as one of the determination lines 51a, 51b, 51c, 51d. . By this determination, it is possible to immediately give an abnormality determination before the moving inspection object W is out of the reception range of the reception coils Cr1 and Cr2.
　または、検査すべき被検査物Ｗが上流の受信コイルＣｒ１の受信範囲に入ってから下流の受信コイルＣｒ２の受信範囲から出るまでの間にリサージュ波形を完成し、完成したリサージュ波形を波形メモリ３５に一時的に保存する。そして、判定部３８において、波形メモリ３５に保持したリサージュ波形がいずれかの判定ライン５１ａ，５１ｂ，５１ｃ，５１ｄと交差しまたは接するか否かを判定してもよい。 Alternatively, the Lissajous waveform is completed between the time when the inspection object W to be inspected enters the reception range of the upstream reception coil Cr1 and the time when it exits the reception range of the downstream reception coil Cr2, and the completed Lissajous waveform is stored in the waveform memory 35. Temporarily save to. Then, the determination unit 38 may determine whether the Lissajous waveform held in the waveform memory 35 intersects or touches any of the determination lines 51a, 51b, 51c, 51d.
　この金属検査装置１では、図６に示すように、操作部２６の操作で判定ラインまたは領域設定部３６を動作させて、Ｘ－Ｙ座標上に判定領域５２ａ，５２ｂ，５２ｃ，５２ｄを設定することもできる。以下では、判定領域を総称して符号５２で示すことがある。 In this metal inspection apparatus 1, as shown in FIG. 6, the determination line or region setting unit 36 is operated by operating the operation unit 26 to set the determination regions 52a, 52b, 52c, and 52d on the XY coordinates. You can also. Hereinafter, the determination area may be collectively indicated by reference numeral 52.
　判定ライン５１と同様に、判定領域５２ａ，５２ｂ，５２ｃ，５２ｄは波形メモリ３５に記憶されている基準リサージュ波形４１と重ならない座標位置に設定される。判定領域５２は、ループ形状に描かれる基準リサージュ波形４１で囲まれた内側領域に設定され、または、基準リサージュ波形４１の外側領域に設定される。好ましくは、判定領域５２は、基準リサージュ波形４１で囲まれた領域の内側と外側の双方に設定される。 Like the determination line 51, the determination areas 52a, 52b, 52c, and 52d are set to coordinate positions that do not overlap the reference Lissajous waveform 41 stored in the waveform memory 35. The determination area 52 is set in an inner area surrounded by the reference Lissajous waveform 41 drawn in a loop shape, or is set in an outer area of the reference Lissajous waveform 41. Preferably, the determination area 52 is set both inside and outside the area surrounded by the reference Lissajous waveform 41.
　図６に示すように、判定領域５２は、長方形、正方形、台形などの多角形で設定される、または円形や楕円形などの形状に設定することもできる。 As shown in FIG. 6, the determination area 52 can be set as a polygon such as a rectangle, a square, or a trapezoid, or can be set as a shape such as a circle or an ellipse.
　判定領域５２ａ，５２ｂ，５２ｃ，５２ｄは、判定ライン５１と同様に、判定ラインまたは領域メモリ３７に記憶され、判定部３８では、検査中のリサージュ波形がいずれかの判定領域５２ａ，５２ｂ，５２ｃ，５２ｄと交差しまたは接するなどして同じ座標点を共有したら、金属の異物を含んでいるおそれがあると判定する。 The determination areas 52a, 52b, 52c, and 52d are stored in the determination line or the area memory 37 in the same manner as the determination line 51, and the determination unit 38 determines which Lissajous waveform under examination is one of the determination areas 52a, 52b, 52c, If the same coordinate point is shared by crossing or contacting 52d, it is determined that there is a possibility of containing a metal foreign object.
　以下では、判定ライン５１ａ，５１ｂ，５１ｃ，５１ｄまたは判定領域５２ａ，５２ｂ，５２ｃ，５２ｄをＸ－Ｙ座標上で設定するための具体的な方法を説明する。 Hereinafter, a specific method for setting the determination lines 51a, 51b, 51c, 51d or the determination areas 52a, 52b, 52c, 52d on the XY coordinates will be described.
　まず、正常な被検査物Ｗ（１０枚のロースハムが包装材で真空パックされた正常な被検査物Ｗ）を搬送機構２に設置し、送信コイルＣｔと受信コイルＣｒ１，Ｃｒ２の間に一定の速度で供給して、図５と図６に示す基準リサージュ波形４１を求め、これを波形メモリ３５に記憶させる。 First, a normal inspection object W (a normal inspection object W in which 10 pieces of roast ham are vacuum-packed with a packaging material) is installed in the transport mechanism 2, and a certain amount is set between the transmission coil Ct and the reception coils Cr1 and Cr2. By supplying at a speed, the reference Lissajous waveform 41 shown in FIGS. 5 and 6 is obtained and stored in the waveform memory 35.
　次に、図４（Ａ）に示すように、微細な磁性金属粉である鉄粉を含む金属試料５５を正常な被検査物Ｗの搬送方向の中央部（ｉ）に載せ、搬送機構２に設置する。この被検査物を送信コイルＣｔと受信コイルＣｒ１，Ｃｒ２の間に一定の速度で供給すると、図７に示す異常リサージュ波形４２が生成される。この異常リサージュ波形４２の波形信号を波形メモリ３５に記憶させる。 Next, as shown in FIG. 4 (A), a metal sample 55 containing iron powder, which is a fine magnetic metal powder, is placed on the central portion (i) in the transport direction of a normal inspection object W and placed on the transport mechanism 2. Install. When this inspection object is supplied between the transmission coil Ct and the reception coils Cr1, Cr2, an abnormal Lissajous waveform 42 shown in FIG. 7 is generated. The waveform signal of the abnormal Lissajous waveform 42 is stored in the waveform memory 35.
　金属試料５５を被検査物Ｗの搬送方向の前部（ｉｉ）に載せると、図８に示す異常リサージュ波形４３が生成され、金属試料５５を被検査物の搬送方向の後部（ｉｉｉ）に載せると、図９に示す異常リサージュ波形４４が生成される。これら異常リサージュ波形４３，４４の波形信号をそれぞれ波形メモリ３５に記憶させる。 When the metal sample 55 is placed on the front part (ii) in the conveyance direction of the inspection object W, an abnormal Lissajous waveform 43 shown in FIG. 8 is generated, and the metal sample 55 is placed on the rear part (iii) in the conveyance direction of the inspection object. Then, an abnormal Lissajous waveform 44 shown in FIG. 9 is generated. The waveform signals of these abnormal Lissajous waveforms 43 and 44 are stored in the waveform memory 35, respectively.
　次に、図４（Ｂ）に示すように、微細な非磁性金属粉であるステンレス鋼粉を含む金属試料５６を、被検査物Ｗの中央部（ｉ）に載せて、送信コイルＣｔと受信コイルＣｒ１，Ｃｒ２の間に一定の速度で供給すると、図１０に示す異常リサージュ波形４５が生成される。また、金属試料５６を被検査物Ｗの前部（ｉｉ）に載せると、図１１に示す異常リサージュ波形４６が得られ、金属試料５６を被検査物Ｗの後部（ｉｉｉ）に載せると、図１２に示す異常リサージュ波形４７が得られる。異常リサージュ波形４５，４６，４７は波形メモリ３５に記憶される。 Next, as shown in FIG. 4B, a metal sample 56 containing stainless steel powder, which is a fine non-magnetic metal powder, is placed on the center part (i) of the inspection object W, and the transmission coil Ct and the reception are received. When a constant speed is supplied between the coils Cr1 and Cr2, an abnormal Lissajous waveform 45 shown in FIG. 10 is generated. When the metal sample 56 is placed on the front part (ii) of the inspection object W, an abnormal Lissajous waveform 46 shown in FIG. 11 is obtained, and when the metal sample 56 is placed on the rear part (iii) of the inspection object W, FIG. An abnormal Lissajous waveform 47 shown in FIG. The abnormal Lissajous waveforms 45, 46 and 47 are stored in the waveform memory 35.
　複数の異常リサージュ波形４２ないし４７が得られた後に、判定ラインまたは領域設定部３６において、基準リサージュ波形４１とは交差しまたは接することなく、全ての異常リサージュ波形４２ないし４７が交差しまたは接する座標位置に判定ライン５１が設定される。同様にして判定領域５２が設定される。 After the plurality of abnormal Lissajous waveforms 42 to 47 are obtained, the coordinates at which all the abnormal Lissajous waveforms 42 to 47 intersect or contact each other without intersecting or contacting the reference Lissajous waveform 41 in the determination line or region setting unit 36. A determination line 51 is set at the position. Similarly, the determination area 52 is set.
　判定ライン５１または判定領域５２を設定するときに、前記６種類の異常リサージュ波形４２ないし４７の全てを使用することが好ましいが、異常リサージュ波形４２ないし４７の一部のものだけを使用して、判定ライン５１または判定領域５２を設定してもよい。 When setting the determination line 51 or the determination region 52, it is preferable to use all of the six types of abnormal Lissajous waveforms 42 to 47, but using only a part of the abnormal Lissajous waveforms 42 to 47, The determination line 51 or the determination area 52 may be set.
　例えば、磁性金属を含む金属試料５５を中央部（ｉ）に設置して得られた異常リサージュ波形４２と、非磁性金属を含む金属試料５６を中央部（ｉ）に設置して得られた異常リサージュ波形４５を比較すると、波形の特徴が大きく相違している。したがって、この２つの異常リサージュ波形４２，４５が交差しまたは接する座標位置に、判定ライン５１または判定領域５２を設定すると、他の異常リサージュ波形４３，４４，４６，４７も、判定ライン５１または判定領域５２を交差しまたは接するようになる。 For example, an abnormal Lissajous waveform 42 obtained by installing a metal sample 55 containing a magnetic metal in the central part (i) and an abnormality obtained by installing a metal sample 56 containing a nonmagnetic metal in the central part (i) When the Lissajous waveform 45 is compared, the characteristics of the waveforms are greatly different. Accordingly, when the determination line 51 or the determination region 52 is set at a coordinate position where the two abnormal Lissajous waveforms 42 and 45 intersect or touch each other, the other abnormal Lissajous waveforms 43, 44, 46, and 47 are also determined by the determination line 51 or the determination region 52. The region 52 intersects or touches.
　また、金属試料５５を前部（ｉｉ）に配置して得られた図８に示す異常リサージュ波形４３と、後部（ｉｉｉ）に配置して得られた図９に示す異常リサージュ波形４４とを比較すると、この２つの波形は、原点Ｏを中心としたほぼ１８０度の回転対称となる。したがって、異常リサージュ波形４３，４４のいずれか一方を得れば、判定ライン５１または判定領域５２の適正な設定位置を予測することができる。これは図１１に示す異常リサージュ波形４６と図１２に示す異常リサージュ波形４７との関係においても同じである。 Further, the abnormal Lissajous waveform 43 shown in FIG. 8 obtained by arranging the metal sample 55 in the front part (ii) and the abnormal Lissajous waveform 44 shown in FIG. 9 obtained by arranging in the rear part (iii) are compared. Then, these two waveforms are approximately 180 degrees rotationally symmetric about the origin O. Therefore, if one of the abnormal Lissajous waveforms 43 and 44 is obtained, an appropriate set position of the determination line 51 or the determination region 52 can be predicted. This also applies to the relationship between the abnormal Lissajous waveform 46 shown in FIG. 11 and the abnormal Lissajous waveform 47 shown in FIG.
　判定ライン５１または判定領域５２を作成する方法は、表示画面３４ａに基準リサージュ波形４１と複数の異常リサージュ波形を表示させ、操作部２６を操作してＸ－Ｙ座標上に判定ライン５１を描き、または判定領域５２の画像を作成して、判定ラインまたは領域メモリ３７に記憶させる。 The determination line 51 or the determination area 52 is created by displaying the reference Lissajous waveform 41 and a plurality of abnormal Lissajous waveforms on the display screen 34a, and operating the operation unit 26 to draw the determination line 51 on the XY coordinates. Alternatively, an image of the determination area 52 is created and stored in the determination line or area memory 37.
　あるいは、長さや形状が相違する複数の判定ライン５１や、面積や形状が相違する複数の判定領域５２の複数のパターンを予め判定ラインまたは領域メモリ３７に記憶させておく。表示画面３４ａに基準リサージュ波形４１と複数の異常リサージュ波形を表示させた状態で、操作部２６を操作して、いずれかの判定ライン５１のパターンまたはいずれかの判定領域５２のパターンを選択して、Ｘ－Ｙ座標上に貼り付けてもよい。 Alternatively, a plurality of determination lines 51 having different lengths and shapes and a plurality of patterns of determination regions 52 having different areas and shapes are stored in the determination line or region memory 37 in advance. With the reference Lissajous waveform 41 and a plurality of abnormal Lissajous waveforms displayed on the display screen 34a, the operation unit 26 is operated to select one of the determination line 51 patterns or one of the determination region 52 patterns. , May be pasted on the XY coordinates.
　または、ＣＰＵ内の演算によって、基準リサージュ波形４１と複数の異常リサージュ波形のデータを比較し、基準リサージュ波形４１の座標データと交差したり接することがなく、複数の異常リサージュ波形の座標データと交差しまたは接触する箇所を選び出して、メモリから判定ライン５１または判定領域５２のパターンを呼び出して、自動的に割り振って貼り付けるようにしてもよい。 Or, the data of the reference Lissajous waveform 41 and the plurality of abnormal Lissajous waveforms 41 are compared by the calculation in the CPU, and the coordinate data of the plurality of abnormal Lissajous waveforms are intersected without intersecting or touching the coordinate data of the reference Lissajous waveform 41. Alternatively, a place to be contacted may be selected, the pattern of the determination line 51 or the determination area 52 may be called from the memory, and automatically allocated and pasted.
　なお、判定ライン５１と判定領域５２のいずれか一方を使用するのではなく、判定ライン５１と判定領域５２の双方を一緒に使用してもよい。 Note that either the determination line 51 or the determination area 52 may be used together instead of using either the determination line 51 or the determination area 52.
　図１３は、判定ライン５３と判定領域５４の設定方法の他の実施の形態を示す説明図である。 FIG. 13 is an explanatory diagram showing another embodiment of a method for setting the determination line 53 and the determination area 54.
　図１３では、基準リサージュ波形４１が必ず交差しまたは接するなどして、基準リサージュ波形４１と座標点を共有する領域で、且つ前記異常リサージュ波形がいずれも交差したり接したりせず、異常リサージュ波形と座標点を共有しない領域に判定ライン５３または判定領域５４またはその双方が設定される。この場合に、被検査物Ｗを検査したときに得られるリサージュ波形が全ての判定ライン５３または全ての判定領域５４を交差せず接しないときに異常な被検査物であると判定される。なお、判定ライン５３または判定領域５４は１個または複数個設定される。 In FIG. 13, the reference Lissajous waveform 41 always intersects or touches, so that the reference Lissajous waveform 41 shares the coordinate point and the abnormal Lissajous waveform does not intersect or touch any other, and the abnormal Lissajous waveform. The determination line 53 and / or the determination area 54 are set in an area that does not share coordinate points. In this case, when the Lissajous waveform obtained when the inspection object W is inspected does not intersect all the determination lines 53 or all the determination areas 54 and is not in contact with each other, it is determined that the object is abnormal. One or more determination lines 53 or determination areas 54 are set.
　また、図５と図６に示す判定ライン５１、判定領域５２と、図１３に示す前記判定ライン５３、判定領域５４を併用してもよい。 Further, the determination line 51 and the determination area 52 shown in FIGS. 5 and 6 may be used together with the determination line 53 and the determination area 54 shown in FIG.
　次に、被検査物Ｗとして食品などの内容物とともに脱酸素剤が封入されるものであっては、脱酸素剤が入っている正常な被検査物を検査して基準リサージュ波形を得て、脱酸素剤を除去した被検査物で異常リサージュ波形を生成してもよい。これにより、脱酸素剤が入っていない異常な被検査物を検知することができる。 Next, in the case where an oxygen scavenger is enclosed with the contents such as food as the object to be inspected W, a normal Lissajous waveform containing the oxygen scavenger is inspected to obtain a reference Lissajous waveform, An abnormal Lissajous waveform may be generated from the inspection object from which the oxygen scavenger has been removed. Thereby, it is possible to detect an abnormal inspection object that does not contain an oxygen scavenger.
　なお、本発明の金属検知装置は、図１に示すように、送信コイルＣｔと受信コイルＣｒ１，Ｃｒ２とが対向しているものに限られず、図１４に示すように、送信コイルＣＴと２個の受信コイルＣＲ１，ＣＲ２が同軸に配置され、被検査物Ｗが各コイルＣＴ，ＣＲ１，ＣＲ２内を通過するものであってもよい。 As shown in FIG. 1, the metal detection device of the present invention is not limited to the one in which the transmission coil Ct and the reception coils Cr1 and Cr2 are opposed to each other. As shown in FIG. The receiving coils CR1 and CR2 may be arranged coaxially, and the inspection object W may pass through the coils CT, CR1 and CR2.
１　金属検知装置
２　搬送機構
１１　交流駆動源
１２　励磁信号
１３　コイル信号
１４　差動アンプ
１５　第１の検波部
１６　第２の検波部
１７　移相回路
１８，１８ａ　第１の検知信号
１９，１９ａ　第２の検知信号
２６　操作部
３０　データ処理部
３２　リサージュ波形生成部
３４ａ　表示画面
３８　判定部
４１　基準リサージュ波形
４２～４７　異常リサージュ波形
５１ａ，５１ｂ，５１ｃ，５１ｄ，５３　判定ライン
５２ａ，５２ｂ，５２ｃ，５２ｄ，５４　判定領域
５５，５６　金属試料
Ｃｒ１，Ｃｒ２，ＣＲ１，ＣＲ２　受信コイル
Ｃｔ，ＣＴ　送信コイル
Ｏ　原点
Ｐ　座標点
Ｗ　被検査物 DESCRIPTION OF SYMBOLS 1 Metal detection apparatus 2 Conveyance mechanism 11 AC drive source 12 Excitation signal 13 Coil signal 14 Differential amplifier 15 1st detection part 16 2nd detection part 17 Phase shift circuit 18, 18a 1st detection signal 19, 19a 2nd Detection signal 26 Operation unit 30 Data processing unit 32 Lissajous waveform generation unit 34a Display screen 38 Determination unit 41 Reference Lissajous waveforms 42 to 47 Abnormal Lissajous waveforms 51a, 51b, 51c, 51d, 53 Determination lines 52a, 52b, 52c, 52d, 54 Determination region 55, 56 Metal sample Cr1, Cr2, CR1, CR2 Reception coil Ct, CT Transmission coil O Origin P Coordinate point W Inspected object

Claims (12)

  1. 　交流の励磁信号が与えられる送信コイルと、複数の受信コイルと、前記送信コイルと前記受信コイルへ向けて被検査物を移動させる搬送機構とが設けられた金属検知装置において、
    　複数の前記受信コイルの誘起電力の比較値から求められるコイル信号を検波する第１の検波部と、前記コイル信号を、前記励磁信号と位相が相違する交流信号で検波する第２の検波部と、前記第１の検波部で得られた第１の検知信号と前記第２の検波部で得られた第２の検知信号とを処理するデータ処理部とが設けられており、
    　前記データ処理部には、前記被検査物の移動に伴って変化する前記第１の検知信号と前記第２の検知信号とから平面座標上にリサージュ波形を描くリサージュ波形生成部と、前記平面座標上に判定ラインまたは判定領域を設定する判定ラインまたは領域設定部と、前記判定ラインまたは前記判定領域と前記リサージュ波形とが同じ座標点を共有したときに、被検査物を異常と判定する判定部と、が設けられていることを特徴とする金属検知装置。     In the metal detection apparatus provided with a transmission coil to which an alternating excitation signal is given, a plurality of reception coils, and a transport mechanism for moving the inspection object toward the transmission coil and the reception coil,
    A first detector for detecting a coil signal obtained from a comparison value of induced electric powers of the plurality of receiving coils; and a second detector for detecting the coil signal with an AC signal having a phase different from that of the excitation signal. A data processing unit for processing the first detection signal obtained by the first detection unit and the second detection signal obtained by the second detection unit;
    The data processing unit includes a Lissajous waveform generation unit that draws a Lissajous waveform on a plane coordinate from the first detection signal and the second detection signal that change with the movement of the inspection object, and the plane coordinate A determination line or region setting unit that sets a determination line or determination region on top, and a determination unit that determines that the inspection object is abnormal when the determination line or determination region and the Lissajous waveform share the same coordinate point And a metal detector.
  2. 　交流の励磁信号が与えられる送信コイルと、複数の受信コイルと、前記送信コイルと前記受信コイルへ向けて被検査物を移動させる搬送機構とが設けられた金属検知装置において、
    　複数の前記受信コイルの誘起電力の比較値から求められるコイル信号を検波する第１の検波部と、前記コイル信号を、前記励磁信号と位相が相違する交流信号で検波する第２の検波部と、前記第１の検波部で得られた第１の検知信号と前記第２の検波部で得られた第２の検知信号とを処理するデータ処理部とが設けられており、
    　前記データ処理部には、前記被検査物の移動に伴って変化する前記第１の検知信号と前記第２の検知信号とから平面座標上にリサージュ波形を描くリサージュ波形生成部と、前記平面座標上に判定ラインまたは判定領域を設定する判定ラインまたは領域設定部と、前記判定ラインまたは前記判定領域と前記リサージュ波形とが同じ座標点を共有しないときに、被検査物を異常と判定する判定部と、が設けられていることを特徴とする金属検知装置。     In the metal detection apparatus provided with a transmission coil to which an alternating excitation signal is given, a plurality of reception coils, and a transport mechanism for moving the inspection object toward the transmission coil and the reception coil,
    A first detector for detecting a coil signal obtained from a comparison value of induced electric powers of the plurality of receiving coils; and a second detector for detecting the coil signal with an AC signal having a phase different from that of the excitation signal. A data processing unit for processing the first detection signal obtained by the first detection unit and the second detection signal obtained by the second detection unit;
    The data processing unit includes a Lissajous waveform generation unit that draws a Lissajous waveform on a plane coordinate from the first detection signal and the second detection signal that change with the movement of the inspection object, and the plane coordinate A determination line or region setting unit that sets a determination line or determination region above, and a determination unit that determines that the inspection object is abnormal when the determination line or determination region and the Lissajous waveform do not share the same coordinate point And a metal detector.
  3. 　前記第１の検波部と前記第２の検波部とでは、位相が互いに９０度相違する交流信号で前記コイル信号が検波される請求項１または２記載の金属検知装置。 The metal detection device according to claim 1 or 2, wherein the coil signal is detected by an AC signal having a phase difference of 90 degrees between the first detection unit and the second detection unit.
  4. 　前記データ処理部に、被検査物の種別ごとに設定される前記判定ラインまたは前記判定領域を複数記憶するメモリが設けられている請求項１ないし３のいずれかに記載の金属検知装置。 The metal detection device according to any one of claims 1 to 3, wherein the data processing unit is provided with a memory for storing a plurality of the determination lines or the determination areas set for each type of the inspection object.
  5. 　前記判定ラインまたは前記判定領域を設定して前記メモリに記憶させる操作部が設けられている請求項４記載の金属検知装置。 The metal detection apparatus according to claim 4, further comprising an operation unit that sets the determination line or the determination area and stores the determination line or the determination area in the memory.
  6. 　前記判定ラインまたは前記判定領域は、正常と判定されるべき被検査物を検査したときの基準リサージュ波形と同じ座標点を共有することがなく、異常と判定されるべき被検査物を検査したときの異常リサージュ波形と同じ座標点を共有する座標位置に設定される請求項１記載の金属検知装置。 The determination line or the determination region does not share the same coordinate point as the reference Lissajous waveform when the inspection object to be determined to be normal is inspected, and the inspection object to be determined to be abnormal is inspected The metal detection device according to claim 1, wherein the metal detection device is set to a coordinate position sharing the same coordinate point as that of the abnormal Lissajous waveform.
  7. 　前記判定ラインまたは前記判定領域は、前記基準リサージュ波形で囲まれる内側領域と、前記基準リサージュ波形の外側の外側領域の少なくとも一方に設定される請求項６記載の金属検知装置。 The metal detection device according to claim 6, wherein the determination line or the determination region is set in at least one of an inner region surrounded by the reference Lissajous waveform and an outer region outside the reference Lissajous waveform.
  8. 　前記判定ラインまたは前記判定領域は、前記内側領域と、前記外側領域の双方に設定される請求項７記載の金属検知装置。 The metal detection device according to claim 7, wherein the determination line or the determination region is set in both the inner region and the outer region.
  9. 　前記判定ラインまたは前記判定領域は、正常と判定されるべき被検査物を検査したときの基準リサージュ波形と同じ座標点を共有し、異常と判定されるべき被検査物を検査したときの異常リサージュ波形と同じ座標点を共有しない座標位置に設定される請求項２記載の金属検知装置。 The determination line or the determination area shares the same coordinate point as a reference Lissajous waveform when an inspection object to be determined to be normal is inspected, and an abnormal Lissajous when an inspection object to be determined to be abnormal is inspected The metal detection device according to claim 2, wherein the metal detection device is set to a coordinate position that does not share the same coordinate point as the waveform.
  10. 　異常リサージュ波形は、正常な被検査物に金属試料を設置したものを検査することで得られる請求項６ないし９のいずれかに記載の金属検査装置。 10. The metal inspection apparatus according to claim 6, wherein the abnormal Lissajous waveform is obtained by inspecting a normal inspection object in which a metal sample is placed.
  11. 　磁性金属の金属試料を用いた異常リサージュ波形と、非磁性金属の金属試料を用いた異常リサージュ波形の双方を得る請求項１０載の金属検査装置。 11. The metal inspection apparatus according to claim 10, wherein both an abnormal Lissajous waveform using a magnetic metal sample and an abnormal Lissajous waveform using a non-magnetic metal sample are obtained.
  12. 　正常な被検査物の異なる位置に金属試料を配置して複数の異常リサージュ波形を得る請求項１０または１１記載の金属検査装置。 The metal inspection apparatus according to claim 10 or 11, wherein a plurality of abnormal Lissajous waveforms are obtained by arranging metal samples at different positions of a normal inspection object.
PCT/JP2013/076985 2013-10-03 2013-10-03 Metal-detection device WO2015049766A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2013/076985 WO2015049766A1 (en) 2013-10-03 2013-10-03 Metal-detection device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2013/076985 WO2015049766A1 (en) 2013-10-03 2013-10-03 Metal-detection device

Publications (1)

Publication Number Publication Date
WO2015049766A1 true WO2015049766A1 (en) 2015-04-09

Family

ID=52778376

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2013/076985 WO2015049766A1 (en) 2013-10-03 2013-10-03 Metal-detection device

Country Status (1)

Country Link
WO (1) WO2015049766A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016217947A (en) * 2015-05-22 2016-12-22 アンリツインフィビス株式会社 Metal detection machine
JP2020153830A (en) * 2019-03-20 2020-09-24 アンリツインフィビス株式会社 Metal detector
CN114026416A (en) * 2019-06-27 2022-02-08 安立股份有限公司 Metal detection device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004086095A1 (en) * 2003-03-12 2004-10-07 Anritsu Industrial Solutions Co., Ltd. Metal detector
JP2007085873A (en) * 2005-09-21 2007-04-05 Tetsuo Sakaki Flaw detector
JP2008058223A (en) * 2006-09-01 2008-03-13 Anritsu Sanki System Co Ltd Metal detector

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004086095A1 (en) * 2003-03-12 2004-10-07 Anritsu Industrial Solutions Co., Ltd. Metal detector
JP2007085873A (en) * 2005-09-21 2007-04-05 Tetsuo Sakaki Flaw detector
JP2008058223A (en) * 2006-09-01 2008-03-13 Anritsu Sanki System Co Ltd Metal detector

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016217947A (en) * 2015-05-22 2016-12-22 アンリツインフィビス株式会社 Metal detection machine
JP2020153830A (en) * 2019-03-20 2020-09-24 アンリツインフィビス株式会社 Metal detector
CN114026416A (en) * 2019-06-27 2022-02-08 安立股份有限公司 Metal detection device

Similar Documents

Publication Publication Date Title
US9453817B2 (en) Nondestructive inspection device using alternating magnetic field, and nondestructive inspection method
WO2015049766A1 (en) Metal-detection device
JP6121689B2 (en) Metal detector
JP2013113612A (en) Article inspection apparatus
JP2019168253A (en) Magnetic body inspection system, magnetic body inspection device and magnetic body inspection method
RU2360268C1 (en) Eddy current device
KR101786794B1 (en) Metal detection sensor and metal detector including the same
JP4141987B2 (en) Metal detector
JP2016057225A (en) Eddy current flaw detection sensor device
JP2009109346A (en) Weight screening apparatus with metal detector
JP6339468B2 (en) Inspection equipment
JP2013113784A (en) Article inspection device
JP4902170B2 (en) Inspection system
JP2006064642A (en) Metal detection device
JP4188282B2 (en) Metal detector
JP6103848B2 (en) Foreign object detection device
JP6077764B2 (en) Inspection equipment
JP6046940B2 (en) Inspection equipment
JP6581789B2 (en) Inspection equipment
JP4138179B2 (en) Metal detector
JP7242442B2 (en) metal detector
US11762118B2 (en) Metal detection apparatus
JP4156577B2 (en) Metal detector
Kharangate et al. A novel approach for metal detection in food using curve fitting technique
JP4188284B2 (en) Metal detector and control method thereof

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13895115

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13895115

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP