WO2017213476A1

WO2017213476A1 - High-sensitivity metal detector robust against disturbance

Info

Publication number: WO2017213476A1
Application number: PCT/KR2017/006077
Authority: WO
Inventors: 이길승; 고각현; 김무성; 이진관
Original assignee: 노바센(주)
Priority date: 2016-06-10
Filing date: 2017-06-12
Publication date: 2017-12-14
Also published as: KR101670427B1

Abstract

The present invention relates to a high-sensitivity metal detector robust against disturbance, which can detect metal alien substances entailed in food with improved sensitivity and can remove a disturbance signal, the metal detector comprising: a transfer portion for transferring a to-be-detected object; a magnetization portion arranged on the path of transfer of the to-be-detected object so as to magnetize metal alien substances entailed in the to-be-detected object; a magnetic detection portion comprising multiple magnetic sensors arranged at the rear end of the magnetization portion on the path of transfer so as to detect the magnetic field of the to-be-detected object that has passed through the magnetization portion; and a control portion configured to remove a disturbance signal from magnetic field signals received from the magnetic detection portion and to identify signals from the magnetic sensors that have detected the magnetic field of the metal alien substances.

Description

High Sensitivity Metal Detector Robust to Disturbance

The present invention relates to a metal foreign material detector, and more particularly, to a high sensitivity metal detector that is robust to disturbances capable of removing a disturbance signal while improving detection sensitivity of a metal foreign material mixed in a food.

The metal foreign material detector is a device for detecting metal foreign matter mixed in an inspection product such as food. The metal foreign material detector uses optical detection method using X-ray, eddy current method using high frequency magnetic field, and residual magnetic strength of magnetized metal object by magnetization means. There is an electromagnetic induction method that detects with a magnetic sensor that operates by electromagnetic induction.

The present invention relates to a metal foreign material detector of the electromagnetic induction method for detecting the residual magnetic strength of the magnetized metal foreign objects with a magnetic sensor as follows.

Faraday's law of electromagnetic induction is generalized to the formula ε = -N (dΦ / dt) (unit: V), and the induced electromotive force (ε) is proportional to the rate of change of magnetic flux (Φ) over the number of turns of the coil and over time. At this time, in order to easily detect a signal generated by the movement of the metal foreign material, since the number of windings of the coil is unchanged, the moving speed of the metal foreign material passing through the magnetic field or the degree of magnetization of the metal foreign material should be increased. However, since the moving speed of the metal foreign material depends on the conveying speed of the conveyor belt, there is a practical limit to increase the moving speed of the metal foreign material. Therefore, the conventional metal foreign material detection device mainly improves the detection sensitivity by magnetizing the metal foreign material to sense the signal.

In addition, the detection sensitivity of the detection device should be improved as much as possible to detect small metal foreign substances or metal foreign substances having a weak magnetic field due to the small amount of metal components.If the sensitivity is set sensitively, the magnetic field of the earth and the magnetic field in the installation environment (motor) Due to the significant increase in disturbance signals that interfere with the detection, such as inverters, movement of steel equipment, etc., frequent malfunctions of the device become a problem, and thus the reliability of the detection device is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem of the prior art, and an object of the present invention is to provide a highly sensitive metal detector that is robust against disturbances capable of removing a disturbance signal while improving detection sensitivity of a metal foreign material mixed in a food.

In addition, the present invention is to configure a plurality of magnetic sensors for detecting the magnetic field of the foreign metal, and to form a sensor line by installing the magnetic sensors in a line at a predetermined interval on the line matching the conveying path on the magnetic detection unit, An object of the present invention is to improve detection sensitivity by allowing a plurality of magnetic sensors to continuously detect a metal foreign material conveyed along a conveyance path.

In addition, the present invention is to install the magnetic sensors of the second sensor line at the same interval as the magnetic sensors installed on the adjacent first sensor line, corresponding to the intermediate point of the sensors installed on the first sensor line, each An object of the present invention is to minimize the blind spots from which metal foreign bodies are not detected by effectively narrowing the distance between the sensor lines.

In addition, the present invention is to determine that the signals commonly detected in the plurality of magnetic sensors as disturbance, to effectively remove the disturbance signals in each magnetic sensor.

In addition, an object of the present invention is to synchronize the time axis of each signal value of the magnetic sensors included in each sensor line to amplify the magnetic field signal of the metal foreign material to more clearly identify the metal foreign material.

The highly sensitive metal detector, which is robust against disturbances, according to the present invention for achieving the above object, is disposed on a conveying unit for conveying an object to be detected and on a conveying path of the object to be detected and mixed with the object to be detected. A magnetic detection unit including a magnetization unit for magnetizing the magnetic field, a plurality of magnetic sensors disposed at a rear end of the magnetization unit on the conveyance path, and detecting a magnetic field of the object to be detected passing through the magnetization unit; and a magnetic field received by the magnetic detection unit. It characterized in that it comprises a control unit for identifying the signal of the magnetic sensor for detecting the magnetic field of the metal foreign material by removing the disturbance signal from the signal of.

In addition, the magnetic sensor may be a magnetic resonance (Fluxgate) sensor.

In addition, at one side of the magnetic detection unit, a plurality of magnetic sensors are arranged in a line at a predetermined interval on a line coinciding with the conveyance path, and a plurality of magnetic sensors are parallel to the first sensor line. A plurality of second sensor lines formed in a line at a predetermined interval may be alternately disposed.

In addition, the magnetic sensors of the second sensor line may be installed at the same interval as the magnetic sensors installed on the adjacent first sensor line, it may be installed corresponding to the intermediate point of the sensors installed on the first sensor line. have.

The controller may exclude the disturbance signal from the magnetic sensor based on a difference between the output value of the magnetic sensor and the average output value of the entire magnetic sensor.

The apparatus may further include an entrance monitoring unit disposed at the front end of the magnetic detection unit on the conveying path to detect the presence or absence of the object to be detected, and the control unit may include a point in time at which the object to be detected is detected through the entry monitoring unit and the transport unit. The time for transferring the detected object to the magnetic sensor of the magnetic detection unit may be calculated through the speed of conveying the detected object and the distance between the entry monitoring unit and the magnetic detection unit.

The control unit may detect the signal value of the magnetic sensor disposed at the rear end of the signal values of the magnetic sensors included in any one sensor line from the magnetic sensor disposed at the uppermost end to the magnetic sensor disposed at the rear end. By retracting the time axis by this conveyed time may be characterized in synchronizing the signal values of the magnetic sensors included in any one sensor line.

The controller may derive an amplified signal by summing the synchronized signal values of the magnetic sensors included in any one sensor line, and if the amplified signal is greater than or equal to a predetermined reference, the foreign material may be included in the object to be detected. It may be characterized as being determined.

In addition, the controller discretizes the synchronized signal values of the magnetic sensors included in any one sensor line (A / D Convert), and whether the metal foreign material is included in the detected object through a pre-learned artificial neural network. It may be characterized by determining.

The high sensitivity metal detector robust to disturbance according to the present invention as described above has the following effects.

First, it is possible to provide a high-sensitivity metal detector robust to disturbances capable of removing the disturbance signal while improving the detection sensitivity of the metal foreign matter mixed in the food.

Second, by forming a plurality of magnetic sensors for detecting the magnetic field of the metal foreign matter, and installing the magnetic sensors in a line at a predetermined interval on the line matching the conveying path on the magnetic detection unit to form a sensor line, Accordingly, by sensing a plurality of magnetic sensors continuously with a time difference, it is possible to improve the detection sensitivity of the metal foreign materials.

Third, the magnetic sensors of the second sensor line are installed at the same interval as the magnetic sensors installed on the adjacent first sensor line, but corresponding to the intermediate points of the sensors installed on the first sensor line. By effectively narrowing the gap, it is possible to minimize blind spots from which no metal foreign matter is detected.

Fourth, the signals commonly detected by the plurality of magnetic sensors are determined as disturbances, and thus, the disturbance signals can be effectively removed from each magnetic sensor.

Fifth, by synchronizing the time axis of each signal value of the magnetic sensors included in each sensor line, the magnetic field signal of the metal foreign material is amplified so that the metal foreign material can be more clearly identified.

1 is a front view showing a high sensitivity metal detector robust to disturbance according to an embodiment of the present invention.

FIG. 2 is a plan view partially showing only a carrier, a magnetizer, an entrance monitor, and a magnetic detector of a highly sensitive metal detector resistant to disturbance according to an embodiment of the present invention; FIG.

3 is a reference diagram showing the structure of the magnetic resonance (Fluxgate) sensor and the principle of building the magnetic material.

Figure 4 is a reference diagram showing the schematic structure of the magnetic resonance sensor and the wavelength of the input and output signals.

5 is a B-H Curve graph of the magnetic resonance sensor.

6 is a signal processing process of a magnetic resonance sensor capable of obtaining an output proportional to the magnitude of an external magnetic field with high sensitivity.

7 is a comparative example in which (a) a magnetic sensor is arranged as a checkerboard and (b) the magnetic sensor is configured of a first sensor line and a second sensor line.

8 is a diagram showing the relationship between the electrical components of the high-sensitivity metal detector robust to disturbance according to an embodiment of the present invention.

9 and 10 are views illustrating a process of synchronizing the time axis of the detection values of the magnetic sensors listed in the sensor line based on the time when the controller detects the object to be detected by the entry monitoring unit.

FIG. 11 is a diagram illustrating determining whether a metal foreign material exists by amplifying a signal caused by a metal foreign material by summing a detection value of a magnetic sensor whose time axis is synchronized as an embodiment of the present invention.

12 is another embodiment of the present invention, the structure and algorithm of the artificial neural network for explaining that the control unit to determine whether the metal foreign matter in the detected object through the artificial neural network.

Hereinafter, a preferred embodiment of a high sensitivity metal detector robust to disturbance according to the present invention will be described in detail.

Referring to FIG. 1, a highly sensitive metal detector, which is robust against disturbances, according to an embodiment of the present invention, is disposed on a conveying unit 152 for conveying an object to be detected 10 and a conveying path of the object to be detected 10. The magnetized part 120 which magnetizes the metal foreign material 12 mixed in the to-be-detected object 10, and arrange | positioned at the rear end of the magnetized part 120 on a conveyance path | route, and passed through the magnetized part 120 are detected The metal foreign material 12 by removing the disturbance signal from the magnetic detection unit 110 including a plurality of magnetic sensors 112 for detecting the magnetic field of the water 10 and the magnetic field signal received from the magnetic detection unit 110. And a control unit 160 (see FIG. 8) for identifying a signal from the magnetic sensor 112 that has detected a magnetic field of the magnetic sensor 112.

The apparatus may further include an entrance monitoring unit 130 disposed at the front end of the magnetic detection unit 110 on the transport path to detect the presence or absence of the object to be detected 10.

Here, the detected object 10 may be food, clothing, or the like, but is not limited thereto.

The conveying unit 152 has a function of conveying the detected object 10 in a predetermined direction, and specifically, may be a mechanical device such as a conveyor belt. In FIG. 1, the to-be-detected object 10 put on the conveyance part 152 is conveyed to the right direction. The moving speed of the to-be-detected object 10 is determined by the rotational speed of the motor which drives the conveyance part 152. FIG. The controller 160 controls the rotational speed of the transfer motor 154 to adjust the moving speed of the object to be detected 10 placed on the transfer unit 152.

Referring to FIG. 2, the magnetization unit 120 is provided at a predetermined position on the conveyance path of the object to be detected 10, and the magnetic detection unit 110 is provided at the rear end of the magnetization unit 120 in the conveyance path. The magnetization part 120 and the magnetic detection part 110 are arrange | positioned at predetermined intervals along the conveyance direction of 152. The to-be-detected object 10 passes through the magnetization part 120 and the magnetic detection part 110 sequentially along the conveyance path of the conveyance part 152. FIG.

The magnetization unit 120 serves to magnetize the metal foreign material 12 that may be mixed in the object to be detected 10. The magnetization unit 120 has an edge shape having a cavity area through which the transfer unit 152 passes and surrounds the transfer unit 152. The magnetization unit 120 may be configured at both the upper and lower portions through which the detected object 10 passes, and may magnetize the metal foreign material 12 in the detected object 10 passing therebetween. The magnetization unit 120 may be made of any structure other than a permanent magnet or a permanent magnet as long as it can magnetize a metal material or the like.

When the metal foreign material 12 mixed in the to-be-detected object 10 is magnetized while passing through the magnetization part 120, the detection sensitivity at the magnetic detection part 110 to be passed thereafter is increased.

The magnetic detector 110 has a cavity area through which the carrier 152 passes.

3 to 6, the magnetic sensor 112 provided in the magnetic detector 110 to detect the magnetic field of the object to be detected 10 may be a magnetic resonance sensor having excellent detection sensitivity. The detection range (Gauss) of the magnetic resonance sensor is 10 ^ -6 to 10 ^ -2, and the detection range of the search coil used to detect the metal foreign material 12 is generally 10 ^ -2 to 10. Better than ^ 2.

The magnetic resonance sensor is a magnetic sensor 112 using a saturation characteristic of the B-H curve of a material having a high permeability and is also referred to as a saturation iron core magnetometer. The primary and secondary coils are wound around the magnetic core of high permeability. When a sine wave current with a sufficiently large amplitude of frequency f (hundreds of Hz to several kHz) flows through the primary coil, The induced voltage will deviate from the sine wave. In the absence of an external magnetic field, the voltage waveform of the secondary coil includes harmonics with only odd aberrations, with positive and negative symmetry. However, when an external magnetic field is applied, this symmetry is broken, and thus even harmonics are included. Therefore, if the detector in the signal processing circuit (demodulator) takes only 2 times the excitation frequency (2xf) of the excitation frequency of the DDS (Direct Digital Synthesis) and detects it, the output proportional to the magnitude of the external magnetic field can be obtained with high sensitivity. Will be.

The magnetic field strength of the magnetized metal foreign material 12 is different depending on the size of the metal foreign material 12 and the amount of metal contained therein. Therefore, as the magnetic sensor 112 is used as having an excellent detection range, it is possible to detect finer and various metal foreign materials 12.

However, the magnetic sensor 112 has a problem that an error frequently occurs in a detection range of a predetermined level or more due to disturbance generated in the environment. Disturbance includes a magnetic field generated from the earth magnetic field, the magnetization unit 120 and the transfer motor 154, externally located equipment, worker's belongings, and a vehicle for transporting cargo in the factory. The disturbance as described above may affect the magnetic sensor 112 in a fixed manner, but since there are more factors influencing fluid due to factors such as movement or power supply, the signal pattern of the disturbance magnetic field may be stored in advance. If the signal contains a corresponding pattern, it is virtually impossible to remove. Therefore, there is a limit in developing a device having a detection range of a certain level or more by applying a magnetic resonance (Fluxgate) sensor having an excellent detection range.

The high-sensitivity metal detector, which is robust against disturbances, according to an embodiment of the present invention constitutes a plurality of magnetic sensors 112 as described above, and removes the common signals inputted from the magnetic sensors 112 as disturbances. It solved by doing.

2 and 7, at one side of the magnetic detection unit 110, a plurality of magnetic sensors 112 are formed in a line on a line coinciding with a conveying path, and are formed in a line at a predetermined interval, and a plurality of magnetic sensors 112. The magnetic sensor 112 is installed in a line at a predetermined interval in parallel with the first sensor line to form a plurality of second sensor lines alternately with each other.

Since the object to be detected 10 is conveyed in only one direction by the conveying unit 152, the metal foreign material 12 included in the object to be detected 10 is conveyed in the same direction, and the magnetic sensors 112 are conveyed in the conveyance path. When arranged in a line coinciding with, all of the magnetic sensors 112 of the line in which the metal foreign material 12 is conveyed sequentially detect the metal foreign material 12, thereby improving detection reliability.

Since the magnetic resonance (Fluxgate) sensor generates a magnetic field by itself, it is preferable that the plurality of magnetic sensors 112 are spaced at regular intervals so as not to cause interference by each other. In addition, the magnetic sensor 112 should be arranged at regular intervals in the left and right directions and the vertical direction to arrange as many magnetic sensors 112 as possible in the magnetic detection unit 110, and the foreign metal contained in the object to be detected 10. It is possible to minimize blind spots where (12) is not detected.

In particular, the magnetic sensors 112 of the second sensor line are installed at the same interval as the magnetic sensors 112 installed on the adjacent first sensor line, but at the intermediate point of the magnetic sensors 112 installed on the first sensor line. It can be installed correspondingly. If the magnetic sensor 112 is arranged in this form, the separation distance between the magnetic sensors 112 can be maintained the same, and the sensor lines can be arranged more precisely in the direction of the conveying path than the magnetic sensor 112 is arranged only in the form of a checkerboard. do. The magnetic sensor 112 may obtain a higher magnetic field signal as the magnetic sensor 112 is closer to the metal foreign material 12, thereby further improving the detection capability of the metal foreign material 12.

In addition, the magnetic detection unit 110 is disposed on the upper and lower portions of the magnetic sensor 112, the magnetic detection unit 110 between the upper magnetic sensor 112 and the lower magnetic sensor 112 to be detected (10). May be implemented to allow it to pass (see FIG. 2). In particular, the magnetic sensors 112 disposed on the upper portion of the magnetic detection unit 110 are disposed at portions corresponding to positions between the sensor lines of the magnetic sensors 112 disposed on the lower portion thereof, whereby the upper and lower magnetic sensors 112 are disposed. The separation distance between the two electrodes may be further increased, and the upper magnetic sensor 112 may cover the detection of an area in which the magnetic sensor 112 is not disposed in the lower portion of the magnetic detection unit 110.

Although the magnetization unit 120 and the magnetic detection unit 110 have been described as having an edge shape having a cavity area, the magnetization unit 120 and the magnetic detection unit 110 may have other shapes (for example, a cylindrical shape). That is, the upper portion and the lower portion of the transfer unit 152 may be separate components spaced apart from each other.

The entry monitoring unit 130 is configured to detect the presence or absence of the detected object 10 in order to calculate an absolute time for the conveyed object 10 to reach each of the magnetic sensors 112 of the magnetic detection unit 110. . As illustrated in FIG. 2, the entry monitoring unit 130 may be configured as a photo sensor, and the light emitting unit 130b and the light receiving unit 130a may be disposed at both sides of the transfer unit 152. In addition, as another embodiment, it is composed of an ultrasonic sensor or a laser sensor or the like to detect the sound wave or light reflected by the object to be detected 10 to determine the presence or absence of the object to be detected 10 directly or indirectly ( Any means capable of detecting the entry of 10) can be applied.

In addition, in order to calculate a delay time until the detected object 10 detected by the entry monitoring unit 130 reaches each of the magnetic sensors 112, the control unit 160 includes an entry monitoring unit 130 and each. Preferably, the separation distance of the magnetic sensor 112 is stored in advance.

Referring to FIG. 8, the controller 160 is connected to the magnetic sensor 112, the entry monitoring unit 130, the transfer motor 154, and the like of the magnetic detection unit 110 to receive the detected signal. And control.

The metal foreign material 12 included in the object to be detected 10 detects a magnetic field only in the magnetic sensor 112 adjacent to the conveyed path, but has a disturbance magnetic field signal having an intensity that affects the magnetic sensor 112. Is commonly detected simultaneously in all the magnetic sensors 112 included in the magnetic detector 110. That is, when the signals received in common among the signal values received by the magnetic sensors 112 are excluded, disturbances are removed from the detection values of the magnetic sensors 112 as a result.

Accordingly, the controller 160 removes the disturbance signal from the output values detected by the plurality of magnetic sensors 112 (the output value of each magnetic sensor 112 (

) And the total number N of magnetic sensors 112, the average output value of the total magnetic sensors 112 (

) Is calculated.

[Equation 1]

In addition, the controller 160 may output an output value of any one of the magnetic sensors 112 (

) And the average output value of the entire magnetic sensor 112 (

Output value of any one of the magnetic sensors 112 except for the disturbance signal

) Can be obtained.

[Equation 2]

In addition, the controller 160 controls the time T at the point in time when the detected object 10 is detected through the entry monitoring unit 130 and the speed at which the conveying unit 152 conveys the detected object 10 ( V), the separation distance between the entrance monitoring unit 130 and the magnetic sensors 112 of the magnetic detection unit 110 (

The time at which the object to be detected 10 reaches the magnetic sensor 112 of the magnetic detection unit 110 through

) Is calculated.

The magnetic sensor 112 is disposed along the conveying path line on the magnetic detecting unit 110, and the object to be detected 10 is excessively subjected to the magnetic sensors 112 at a constant speed by the conveying unit 152. 112 may detect the magnetic field of the metal foreign material 12 in the order listed. Therefore, even if each magnetic sensor 112 detects the magnetic field of the metal foreign material 12, a difference occurs in the detection time, so as to detect the metal foreign material 12 at the same time by adjusting the time axis of the magnetic sensors 112 to synchronize I need to.

9 and 10, the controller 160 determines whether the magnetic field of the metal foreign material 12 is detected from the signal values of the magnetic sensors 112 included in the path in which the metal foreign material 12 is conveyed. Synchronize the time axis of the signal values of the respective magnetic sensors 112 in order to compare and judge.

Specifically, the control unit 160 at the magnetic sensor 112 disposed at the top of the signal value of the magnetic sensor 112 disposed at the rear end of each signal value of the magnetic sensors 112 included in any one sensor line By retracting the time axis by the time that the object to be detected 10 is conveyed to the magnetic sensor 112 disposed at the rear end, it is possible to synchronize the signal values of the magnetic sensors 112 included in any one sensor line.

The time when the detected object 10 is conveyed from the magnetic sensor 112 disposed at the top end to the magnetic sensor 112 disposed at the rear end is the time when the detected object 10 is detected by the entry monitoring unit 130. And, it can be calculated through the conveyance speed, the distance between the entry monitoring unit 130 and each magnetic sensor 112.

Referring to FIG. 11, as an example of determining whether the magnetic field signal of the metal foreign material 12 is included from the signal values of the synchronized magnetic sensors 112, the controller 160 is included in one sensor line. The sum of the synchronized signal values of the magnetic sensors 112 may be used to derive an amplified signal, and if the amplified signal is greater than or equal to a predetermined reference value, it may be determined that the metal foreign material 12 is included in the detected object 10. .

The detected object 10 without the metal foreign material 12 is removed from the magnetic sensor 112 included in any one of the sensor lines because the unique magnetic field generated in the product and the packaging material is removed together when the disturbance signal is removed. Although the magnitude of the signal to be amplified by the sum of the signal values is a small level, the detected object 10 including the metal foreign material 12 is continuously connected to the magnetic sensors 112 included in at least one sensor line. Since the magnetic field of the foreign material 12 is detected, the signal values generated by the magnetic field of the metal foreign material 12 are remarkably amplified by adding up the signal values of the magnetic sensor 112 whose time axis is synchronized.

In addition, referring to FIG. 12, as another embodiment, the controller 160 discretizes the synchronized signal values of the magnetic sensors 112 included in any one sensor line (A / D Convert), and then the previously learned values. It may be determined whether the metal foreign material 12 is included in the detected object 10 through an artificial neural network.

Discretization converts the signal value of the magnetic sensor 112 to be represented by only two values, 0 and 1.

In addition, the control unit 160 amplifies the signal value by the method of the embodiment, and then discretizes the signal amplified by the method of another embodiment, and then detects the object 10 through the pre-learned artificial neural network. It may be determined whether the foreign metal 12 in the inclusion.

The control unit 160 determined that the metal object 12 is included in the detected object 10 may include the metal foreign material 12 through an output means that may be selectively included in an embodiment of the present invention, such as a warning light 170. Can be alerted or physically detached from the transport path 10.

One embodiment of the present invention may further include a power switch 144 for driving the metal detector, and a controller 142 that can set the transfer speed, detection sensitivity, and the like of the transfer unit 152.

It will be understood that the present invention is implemented in a modified form without departing from the essential features of the present invention as described above. Therefore, the described embodiments should be considered in descriptive sense only and not for purposes of limitation, and the scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the equivalent scope are included in the present invention. It should be interpreted.

Claims

A conveying unit for conveying the object to be detected,

A magnetization part disposed on a conveyance path of the object to be detected and magnetizing a metal foreign material mixed into the object to be detected;

A magnetic detector disposed at the rear end of the magnetization portion on the conveyance path and including a plurality of magnetic sensors for detecting a magnetic field of the object to be detected passing through the magnetization portion;

And a controller for removing a disturbance signal from a signal of the magnetic field received by the magnetic detection unit to identify a signal of a magnetic sensor that detects the magnetic field of the metal foreign material.
The method of claim 1,

The magnetic sensor is a highly sensitive metal detector, characterized in that the magnetic resonance (Fluxgate) sensor.
The method of claim 1,

On one side of the magnetic detection unit, a plurality of magnetic sensors are arranged in a line at a predetermined interval on a line coinciding with the conveyance path, and a plurality of magnetic sensors are arranged at a predetermined interval in parallel with the first sensor line. A high sensitivity metal detector robust to disturbance, characterized in that a plurality of second sensor lines are formed in a row arranged alternately with each other.
The method of claim 3, wherein

The magnetic sensors of the second sensor line are installed at equal intervals with the magnetic sensors installed on the adjacent first sensor line, and are installed in correspondence with an intermediate point of the sensors installed on the first sensor line. High sensitivity metal detector.
The method of claim 4, wherein

And the control unit excludes the disturbance signal from the magnetic sensor by a difference between the output value of the magnetic sensor and the average output value of the entire magnetic sensor.
The method of claim 5,

A entrance monitoring unit arranged at the tip of the magnetic detection unit on the conveyance path to detect the presence or absence of the object to be detected;

The controller detects the self-detecting unit through a time point at which the detected object is detected through the entry monitoring unit, a speed at which the conveying unit conveys the detected object, and a distance between the entry monitoring unit and the magnetic detecting unit. High sensitivity metal detector robust to disturbance, characterized in that the time to reach the magnetic sensor of the.
The method of claim 6,

The control unit may return the detected object from the magnetic sensor disposed at the uppermost end to the magnetic sensor disposed at the rearmost end of the signal value of the magnetic sensor disposed at the rear end among the signal values of the magnetic sensors included in any one sensor line. A high sensitivity metal detector resistant to disturbance, characterized by synchronizing signal values of magnetic sensors included in any one sensor line by retracting the time axis as much as the time.
The method of claim 7, wherein

The controller derives an amplified signal by summing the synchronized signal values of the magnetic sensors included in any one sensor line, and if the amplified signal is greater than or equal to a predetermined standard, the foreign substance is included in the object to be detected. A high sensitivity metal detector robust to disturbances, characterized in that the judgment.
The method of claim 7, wherein

The control unit discretizes the synchronized signal values of the magnetic sensors included in any one sensor line (A / D Convert), and then determines whether the metal foreign material is included in the detected object through a pre-learned artificial neural network. High sensitivity metal detector robust to disturbance, characterized in that.