JP4395559B2 - Metal detector - Google Patents

Description

  The present invention relates to a metal detection device, and more particularly to a metal detection device capable of continuously detecting the magnetism of metal remaining inside a moving inspection object using a magnetic sensor element.

Conventionally, in the production and distribution process of clothing, food, medicine, etc., for example, metal such as sewing needles and broken parts thereof, broken parts of needles when injected into livestock, contamination of raw materials, fragments of damaged parts of equipment, etc. There are cases in which the product is mixed and damages the user when the product is used, and as the supplier spreads worldwide, there is a limit to the management in the production area. The discovery and removal of such contaminants has been a major problem. In order to cope with this problem, X-ray metal inspection devices using X-rays (see, for example, Patent Document 1), induction coil type magnetic detection devices (see, for example, Patent Documents 2 and 3), superconductivity for mixed metals. A superconducting metal detection device (for example, Patent Document 4) or the like to which is applied is used.
JP 2002-219420 A JP-A-7-198860 JP-A-10-111362 JP 2004-151064 A

  X-ray metal inspection equipment is also used for baggage inspection at airports. However, the equipment is large and the equipment costs are high. There is a problem in terms of. Inductive coil type magnetic detection devices are widely used to detect metal in foods. For example, when used for detecting residual injection needles in partial meat, the magnetic characteristics of the partial meat itself, It is difficult to set the dip phase angle and sensitivity of the magnetic detector due to the magnetic properties of the material stainless steel or iron, the magnetic properties depending on the direction of the injection needle, etc. The two magnetic detectors are different in order to increase the detection accuracy. There is also a problem in terms of detection accuracy depending on the object. Superconducting metal detectors have recently been developed with high-temperature superconducting materials that become superconducting at liquid nitrogen temperatures, making it possible to detect magnetic fields with high sensitivity relatively easily and with many sources of magnetic noise. Measures for the desired food factory line have been studied, and practical application to meat flowing on the line is also being studied, but the superconducting quantum interference device needs to be kept at a low temperature, so the equipment becomes large, reducing the installation space and cost There is a problem in using it for inspection of restricted clothing and food.

  An object of the present invention is to provide a metal detection device that is simple in structure and small in size, can be easily installed on a conventional production line, is relatively inexpensive, and consumes little power.

A metal detection device for detecting metal remaining in an inspection object, wherein the inspection object moving means and an interior of the moving inspection object provided in the first half of the moving means A magnetizing device that magnetizes the metal remaining in the metal, and a detection unit that is provided at a position close to the moving object to be moved in the latter half of the moving means and detects the magnetism of the metal remaining inside A detection unit that detects the presence or absence of the metal remaining inside the inspection object from the measurement result of the detection unit, and is provided in the vicinity of the entry side of the inspection object. A proximity switch that detects entry into a part, and a magnetic impedance sensor disposed in the detection part so as to be in the vicinity of the object to be inspected that moves close to the detection part by the moving means first magnetic cell consisting of And support element, proximate the 10~50mm the position and so as to disposed the same two magnetic sensor elements to each other while the second magnetic sensor element and a pair consisting of magnetic impedance sensor away from the test object A plurality of magnetic detection sensors housed at intervals are arranged, and the magnetic detection sensors are arranged in a row in a direction orthogonal to the moving direction of the inspection object that moves to detect the metal, and the magnetic detection sensor The sensor is housed in a casing in which a magnetic shield material is disposed on the entire surface except the proximity surface to the inspection object, and the control unit performs inspection by detecting the entry of the inspection object by the proximity switch. together to output a metal detection signal by passing time in the detection portion of the object, the output of each of the first magnetic sensor element of the magnetic sensor and the second magnetic Se Calculating a difference between the output of the sub elements, and outputs a metal detection signal if the value of the difference exceeds a predetermined threshold.

The first magnetic sensor element and the second magnetic sensor element may be magnetic impedance sensors, and the magnetic detection sensors may be arranged in a line at a distance of 10 to 30 mm from each other.

  There may be provided a metal detection alarm means for outputting an alarm in response to the output of the metal detection signal, and the approach of the inspection object to the detection part is brought close to the inspection object entry side of the detection part. A proximity switch for detection may be provided, and the control unit may output a metal detection signal only when the inspection object is in the magnetic detection range of the detection unit based on the operation of the proximity switch.

  In the first aspect, the object to be inspected is a tangible object, the moving means is a belt conveyor, and the magnetizing device and the detection unit are arranged close to the lower surface of the nonmagnetic belt on which the object to be inspected of the belt conveyor is mounted. Has been. Furthermore, the magnetism device may be arranged on the upper side of the inspection object that moves on the belt conveyor.

  In the second aspect, the object to be inspected is a tangible object, the moving means is a belt conveyor, and both the magnetism device and the detection unit are close to the lower surface of the nonmagnetic belt on which the object to be inspected of the belt conveyor is mounted. And the upper side of the inspection object moved by the belt conveyor.

  In the third aspect, the inspection object is a liquid stored in a non-magnetic container, and the moving means is a non-magnetic conveyor that moves the container storing the inspection object in a horizontal direction in a vertical state. The apparatus and the detection unit are arranged in the vertical direction so as to be close to the left and right of the container storing the inspection object moving on the conveyor.

  In the fourth aspect, the object to be inspected is a liquid, the moving means is a nonmagnetic pipe through which the liquid flows, and the magnetism device and the detection unit are respectively located upstream and downstream of the nonmagnetic pipe. They are placed close to each other so as to surround the nonmagnetic pipe.

  In the fifth aspect, the object to be inspected is a tangible object, the moving means is a flat surface on which the object to be inspected can be slid along a predetermined path, and the magnetism device and the detection unit slide on the flat surface, respectively. It arrange | positions in the perpendicular direction so that it may adjoin to the inspection target object on the right and left of the inspection target object. The inspection object may be mounted on a non-magnetic container, and the container may slide on a flat surface.

  The moving means for the inspection object may include a separating means for branching and moving the inspection object from which the metal has been detected from the main moving means.

The metal detection device of the present invention has the following effects. That is,
1) It is possible to detect broken pieces of a broken injection needle that have a problem in detection accuracy. This is because a magnetic impedance (MI) sensor, which is a detection element, is used to remove noise generated from the surrounding environment after the metal mixed in the moving inspection object is magnetized by the magnetizing device in the previous stage. This is because, as a set of two, the difference between the respective outputs is calculated, so that the noise component is removed and only the magnetism of the metal can be detected.
2) The metal mixed in the inspection object can be detected with high sensitivity while the structure is simple and small. This is because the metal mixed in the moving inspection object is magnetized by the magnetizing device in the previous stage and then the inspection is perpendicular to the traveling direction of the inspection object within the range where the metal in the inspection object can be detected. This is because magnetic sensors capable of detecting only metal magnetism by removing noise in the width direction of the object are simply arranged in a row horizontally or vertically.
3) A high-performance metal detector can be installed at low cost in a small installation space, and can be operated with low power consumption. This is a combination of two small magnetic impedance (MI) sensors with high detection accuracy, and a detection unit that can detect metal magnetism by obtaining the difference between the output voltages of the two together with a magnetic device for increasing detection accuracy. This is because it is integrated with the moving means of the inspection object.
4) Can be easily installed on existing production lines. This is because the structure is simple and small, so that it can be added without significantly changing the layout of the existing production line, and if wheels are provided, it can be moved easily.
5) Stable operation is possible without being affected by magnetic noise in the environment. This is a set of two magneto-impedance (MI) sensors, and the noise component is removed by calculating the difference between the outputs of each sensor. This is because the magnetic shield material is disposed, and further, the alarm is output only when the inspection object is detected and the metal of the inspection object is detected.
6) By providing an automatic discharge device for an inspection object in which metal is detected, it is easy to select the inspection object in which metal is detected. This is because the inspection object in which metal is detected is automatically discharged from the line, so that the metal detection inspection object can be selected without stopping the line.
7) By providing a detection lamp for each set of detection elements, the metal detection position can be specified two-dimensionally. This is because the metal position in the traveling direction of the inspection object is grasped by the detection alarm, and the position in the direction orthogonal to the traveling direction of the inspection object is grasped by the detection lamp lighting position.

  Next, a metal detection apparatus according to an embodiment of the present invention will be described with reference to the drawings. First, a description will be given of a general configuration common to each embodiment, a magnetism device, and a detection unit having a magnetic detection sensor using a magnetic impedance (MI) sensor element, which is a feature of the metal detection device of the present invention. FIG. 1 is a schematic block configuration diagram of a metal detection device according to first to fifth embodiments of the present invention, FIG. 2 is a schematic side view of a sensor box, and FIG. 3 is a schematic diagram of a magnetic detection sensor. It is sectional drawing.

  As shown in FIG. 1, the metal detection device 10 includes a magnetic detection sensor 31 including two sensor units 32 and 33 each having MI sensor elements 34 and 35, and a plurality of magnetic detection sensors 31 in one row. A control panel including a sensor box 37 to be housed, a detection unit 30 having one or more sensor boxes 37, a magnetism device 40, a proximity switch 53, a moving device 20, an exclusion mechanism 60, and a control unit 50. 51 and a frame 24 that supports each part. The moving device 20 is a conveyor in the first to third embodiments, a pipe through which an inspection object flows in the fourth embodiment, and an inspection object 70 on the pipe in the fifth embodiment. A sliding base that slides. The exclusion mechanism 60 is, for example, a guide stopper that operates by electricity or air pressure in the first to third and fifth embodiments, and a switching valve is used in the fourth embodiment, but is not necessarily provided. .

  The magnetizing device 40 is for magnetizing the metal 71 mixed in the inspection object 70 moving on the moving device 20 in order to increase the detection accuracy of the MI sensor elements 34, 35. Used.

  The proximity switch 53 is a switch that is provided in the vicinity of the entry side of the inspection object 70 of the detection unit 30 and detects the entry of the inspection object 70 into the detection unit 30. The detection information is output to the control unit 50. The controller 50 calculates the passage time of the inspection object 70 through the detector 30 based on the detection information, and outputs a metal detection signal to the detection lamp 52 only during that time. This is because magnetic noise from the outside is removed by using means such as removing noise by using the difference between the two MI sensor elements 34 and 35, or by providing a magnetic shield material 37a on the housing of the sensor box 37. In the environment where the metal detector 10 is normally installed, there are various sources of magnetic noise, and there are sources that are moving. Thus, the detection lamp 52 is turned on each time to prevent confusion. It is not provided in the fourth embodiment. Although there is a role to prevent such confusion due to erroneous detection, there is no problem in detecting the metal 71 of the original inspection object 70 even if the proximity switch 53 is not provided.

  As shown in FIG. 2, in the sensor box 37 for detecting the metal 71 in the close inspection object 70, a plurality of magnetic detection sensors 31 close to the inspection object 70 at the time of inspection are exposed at one end from the housing. Built in one row. It is desirable that a magnetic shield material 37 a is disposed on the entire surface of the sensor box 37 except for the proximity surface to the inspection object 70. This is to avoid disturbance due to the influence of external magnetism on the magnetic detection sensor 31. As the magnetic shield material 37a, for example, a permalloy foil or a cobalt-based amorphous metal foil can be used.

  Further, if a detection lamp (not shown) that displays metal detection corresponding to each magnetic detection sensor 31 is provided on the surface of the sensor box 37, it is easy to grasp the position of the metal detected in the inspection object. However, the common detection lamp 52 may be provided at a place where the inspector of the metal detection device 10 can easily see, or an alarm sound may be generated.

  The length of the sensor box 37 needs to detect the metal 71 in the entire facing surface of the moving inspection object 70, so the built-in magnetic detection sensor 31 needs to cover the entire facing surface of the inspection object 70. There is a length corresponding to the length, and the interval between the magnetic detection sensors 31 is orthogonal to the moving direction when the inspection object 70 is moved in a direction orthogonal to the row of the magnetic detection sensors 31 of the sensor box 37. It is necessary to set an interval that can detect all the metals 71 in all the opposing surfaces of the inspection object 70 to be detected. According to the experimental example, the interval is usually about 10 mm to 30 mm depending on the type of the inspection object 70. As a result, all the metals 71 in the detection range between them can be detected. Thereby, the number of the magnetic detection sensors 31 can be determined.

  In addition, according to the experimental example, the distance to the metal 71 in the inspection object 70 in which the magnetic detection sensor 31 can detect the magnetism of the metal is preferably within 50 mm in order to increase the detection accuracy. In the case of exceeding, it is necessary to provide a sensor box 37 on the opposite surface side and detect from both surfaces. Even in this case, the thickness of the inspection object 70 is desirably within 100 mm.

  Inside the magnetic detection sensor 31, as shown in FIG. 3, a first sensor portion 32 is provided on the inspection object 70 side, and a second sensor portion 33 is provided on the opposite side. Then, it is connected to the control unit 50 in the control panel 51. The first sensor unit 32 and the second sensor unit 33 are provided with an MI sensor element 34 and an MI sensor element 35 for detecting magnetism, respectively. Depending on the use conditions, the MI sensor element may be protected by providing a cap (not shown) on the exposed portion of the magnetic detection sensor 31 from the sensor box 37.

  The MI sensor elements 34 and 35 are elements of a magnetic impedance (MI) sensor. The magnetic impedance (MI) sensor is a magnetic sensor that senses magnetism using the magnetic impedance effect, and is combined with the GPS function of the mobile phone. In addition to being used for location-based services as an orientation sensor, development of applications such as high-sensitivity non-contact recognition and identification, geomagnetic detection, and residual magnetic detection is under consideration.

  Normally, there are many magnetic sources in the environment where the metal detector 10 is installed, and it is difficult to detect the metal 71 accurately unless the influence of the noise is removed. The first sensor portion 32 is provided on the side facing the inspection object 70 inside the magnetic detection sensor 31, and the second sensor portion 33 is provided on the opposite side. The MI sensor element 34 of the sensor unit 32 detects the magnetism of the metal 71 in the inspection object 70 together with the surrounding magnetic noise, and the MI sensor element 35 of the second sensor unit 33 detects only the surrounding magnetic noise. Since the two sensor elements are provided close to each other, the surrounding magnetic noise to be detected is considered to be substantially the same. When the two sensor elements are separated from each other, a difference occurs between the surrounding magnetic noises detected by the two sensor elements. When the two sensor elements are too close, the MI sensor element 35 of the second sensor unit 33 is affected by the magnetism of the metal 71. According to the experimental example, the distance between the two sensor elements 34 and 35 is preferably 10 to 30 mm in accordance with the use conditions. Therefore, the magnetism of the metal 71 can be calculated by calculating the difference between the gains detected by the two sensor elements 34 and 35 by the control unit 50.

  The control unit 50 is connected to the sensor box 37 with a cable, and inputs and outputs power and signals. The MI sensor element 34 and the second sensor element 32 of the first sensor unit 32 of each magnetic detection sensor 31 of the sensor box 37 are connected. The difference between the gains detected by the MI sensor element 35 of the sensor unit 33 is calculated, and when the value exceeds a threshold value, a detection signal is output. For example, a detection lamp provided at a predetermined location is lit for a predetermined time. The detection lamp may blink or generate an alarm sound. When a detection lamp is provided at a position corresponding to the magnetic detection sensor 31 of the sensor box 37, the inspector can also know the position of the metal 71 by the lit detection lamp. Here, as described above, the proximity switch 53 is provided so that the detection signal is output to the detection lamp 52 only while the inspection object 70 passes through the detection unit 30.

  FIG. 4 shows a control circuit block diagram of the control unit 50. The output from the first sensor unit 32 is filtered and amplified by the high-pass filter 81 a and the amplifier 82 a and is input to the subtraction circuit 83. The output from the second sensor unit 33 is also filtered and amplified by the high-pass filter 81 b and the amplifier 82 b and input to the subtraction circuit 83. The subtraction circuit 83 performs a subtraction process between the two input values, and the subtraction result is filtered by the low-pass filter 84 and input to the comparator 85 and compared with the positive threshold value 86a and the negative threshold value 86b. In the case of exceeding, an alarm output signal is output by the pulse generator 87.

  Next, the metal detection apparatus according to the first embodiment of the present invention will be described. 5A and 5B are schematic outline views of the metal detection device according to the first embodiment. FIG. 5A is a top view and FIG. 5B is a partial cross-sectional side view. The metal detection device 11 according to the first embodiment targets an inspection object 70 having a relatively small thickness, and uses a belt conveyor as a moving device 20 to detect a metal 71 inside the inspection object 70 moving on the conveyor belt 21. To detect. The moving device 20 is held by a frame 24, and a conveyor belt 21 of a belt conveyor is driven by a conveyor driving unit 22 and is tensioned by a tension roller 23.

In FIG. 5B, h ₁ is the maximum height of the inspection object 70, and here it is 50 mm in accordance with the detection capability of the magnetic detection sensor 31 scheduled to be used, but the detection capability of the magnetic detection sensor 31. If it improves, it can be set as the corresponding height. The inspection object 70 is supplied to the conveyor belt 21 from the left side of FIG. 5, metal detection is performed during the movement, and the inspection object 70 is discharged from the right side. The inspection object 70 may be manually supplied one by one, or a supply conveyor and a discharge conveyor connected to the transport belt 21 may be provided, and the inspection may be automatically and continuously performed.

A magnetizing device 40 is provided on the front half of the conveying belt 21 so as to be supported by the frame 24, and a lower magnet 41 is provided on the lower side of the magnetizing device 40 so as to face the back surface of the conveying belt 21. Is provided with an upper magnet 42 facing the surface of the conveyor belt 21 and spaced from the surface by more than h ₁ . Although a detection lamp 52 for notifying metal detection is provided on the upper magnet 42, the position of the detection lamp 52 is not limited to this, and may be a place where an inspector can easily see.

  In the latter half of the conveyance belt 21, the MI sensor element 34 of the magnetic detection sensor 31 is close to the back surface of the conveyance belt 21, and the row of the magnetic detection sensors 31 of the sensor box 37 is orthogonal to the moving direction of the inspection object 70. A sensor box 37 is provided. Further, a proximity switch 53 that detects the entry of the detection object 70 is provided in the vicinity of the upstream side of the sensor box 37.

  An exclusion mechanism 60 is provided on the upper surface of the conveyor belt 21 downstream of the sensor box 37. The guide stopper 61 that is operated by electricity or air pressure is always at a position away from the top of the transport belt 21, and when the magnetic detection sensor 31 detects the metal 71 in the inspection object 70, the control section 50 controls the top of the transport belt 21. The inspection object 70 in which the metal 71 is detected is fed into the collection box 62. In the case where metal detection is performed automatically and continuously, it is necessary to provide an exclusion mechanism 60 for automation of operation. However, the inspector sends the inspection object 70 to the moving device 20, and the detection lamp 52 detects the metal 71. Since the inspector only has to remove the inspection object 70 from which the metal 71 is detected, it is not necessary to provide the exclusion mechanism 60.

  As described above, the inspection object 70 supplied to the entrance of the conveyor belt 21 of the belt conveyor which is the moving device 20 is sent by the moving device 20, and first, between the lower magnet 41 and the upper magnet 42 of the magnetizing device 40. If the metal 71 is mixed in the inspection object 70, the metal 71 becomes magnetized, and the metal 71 is detected by the magnetic detection sensor 31 built in the next sensor box 37. When magnetism is detected, the detection lamp 52 is turned on, and the inspector removes the inspection object 70 from which the metal 71 has been detected. When the inspector has the removal mechanism 60, the removal mechanism 60 has detected the metal 71. The inspection object 70 is excluded from the conveyance belt 21. When there is no hindrance to the operation of the supply conveyor and the discharge conveyor connected to the conveyance belt 21, the conveyance belt 21 may be stopped when the metal 71 is detected.

  Here, the magnetism device 40 has a lower magnet 41 and an upper magnet 42. However, if the strong lower magnet 41 can be used or the thickness of the inspection object 70 is thin, the upper magnet 42 is not provided. May be.

Next, a metal detection device according to a second embodiment of the present invention will be described. 6A and 6B are schematic external views of the metal detection device according to the second embodiment. FIG. 6A is a top view and FIG. 6B is a partial cross-sectional side view. In the metal detection device 11 of the first embodiment, the object 70 to be inspected is relatively thin. However, the metal detection device 12 of the second embodiment is thicker than the first embodiment. The thick inspection object 70 is targeted. In the metal detection device 11 of the first embodiment, the maximum height h ₁ of the inspection object 70 in FIG. 5B is 50 mm, but in the metal detection device 12 of the second embodiment, FIG. maximum height h ₂ of the test object 70) is set to 100 mm. Correspondingly, the position of the upper magnet 42 of the magnetism device 40 is changed, and the sensor box 37 provided only on the lower surface of the conveyor belt 11 is also provided on the upper side of the conveyor belt 11. Since the configuration and function are the same, the same components are denoted by the same reference numerals and description thereof is omitted.

  Next, a metal detection device according to a third embodiment of the present invention will be described. 7A and 7B are schematic outline views of the metal detection device according to the third embodiment. FIG. 7A is a top view and FIG. 7B is a partial cross-sectional side view. The metal detection device 11 of the first embodiment and the metal detection device 12 of the second embodiment are intended for the inspection object 70 that is a tangible object, but the metal detection device 13 of the third embodiment. Uses the liquid stored in the non-magnetic liquid container 72 as the inspection object 70. Specific examples of the liquid stored in the non-magnetic liquid container 72 include drinks stored in glass bottles and plastic bottles, but aluminum is a non-magnetic material even if it is a metal. It can also be applied to the detection of metals in canned beverages.

  In FIG. 7, the belt conveyor is used as the moving device 20, and the metal 71 in the inspection object 70 that is liquid stored in the liquid container 72 that moves on the conveying belt 21 is detected. It is not limited to a conveyor, and may be a slat conveyor or the like, for example, as long as the transport portion is a non-magnetic material. The moving device 20 is held by a frame 24, and a conveyor belt 21 of a belt conveyor is driven by a conveyor driving unit 22 and is tensioned by a tension roller 23.

H _{3 in} FIG. 7B is the maximum height of the liquid that is the inspection object 70, and can be set according to the height of the inspection object 70 by changing the height of the magnetism device 40 and the detection unit 30. However, since the metal 71 is generally not on the upper part of the liquid, it may be set to a height at which the metal 71 may be mixed. On the other hand, the diameter of the liquid container 72 is limited by the detection capability of the magnetic detection sensor 31. If the detection capability for obtaining high accuracy of the magnetic detection sensor 31 planned to be used here is 50 mm, the diameter of the liquid container 72 is 100 mm. Within. If the detection capability of the magnetic detection sensor 31 is improved, the corresponding diameter can be obtained.

  The liquid container 72 in which the inspection object 70 is accommodated is supplied to the transport belt 21 from the left side of FIG. 7, metal detection is performed during movement, and the liquid container 72 is discharged from the right side. The liquid containers 72 may be supplied manually one by one, and a supply conveyor and a discharge conveyor connected to the transport belt 21 may be provided, and inspection may be performed automatically and continuously.

  On the both sides of the front half of the transport belt 21, the right magnet 43 and the left magnet 44 of the magnetism device 40 are supported by the frame 24 and provided vertically so as to be close to the liquid container 72 to be transported. Here, a detection lamp 52 for notifying metal detection is provided on the right magnet 42, but the position of the detection lamp 52 is not limited to this, and may be any place where the inspector can easily see.

  On both sides of the rear half of the transport belt 21, a sensor box 37 is supported by the frame 24 so as to be close to the liquid container 72 to which the MI sensor elements 34 and 35 of the magnetic detection sensor 31 of the detection unit 30 are transported. It is provided in the vertical direction. Further, a proximity switch 53 that detects the entry of the detection object 70 is provided in the vicinity of the upstream side of the sensor box 37.

  An exclusion mechanism 60 is provided on the upper surface of the conveyor belt 21 downstream of the sensor box 37. The guide stopper 61 that is operated by electricity or air pressure is always at a position away from the top of the transport belt 21, and when the magnetic detection sensor 31 detects the metal 71 in the inspection object 70, the control section 50 controls the top of the transport belt 21. The liquid container 72 in which the metal 71 is detected is fed into the collection box 62. When the metal detection is performed automatically and continuously, it is necessary to provide an exclusion mechanism 60 for automation of operation. However, the inspector sends the liquid container 72 to the moving device 20 and the detection lamp 52 detects the metal 71. When the detection is visually confirmed, the inspector only has to remove the liquid container 72 in which the metal 71 is detected, so that it is not necessary to provide the exclusion mechanism 60 in particular.

  As described above, the liquid container 72 containing the liquid that is the inspection object 70 supplied to the entrance of the conveyor belt 21 of the belt conveyor that is the moving device 20 is sent by the moving device 20, and first, the right side of the magnetic device 40. When the metal 71 passes through the magnet 43 and the left magnet 44 and is mixed in the inspection object 70 accommodated in the liquid container 72, the metal 71 is magnetized and incorporated in the next sensor box 37. When the metal 71 is detected by the magnetic detection sensor 31 and the magnetism of the metal 71 is detected, the detection lamp 52 is turned on, and the inspector removes the liquid container 72 from which the metal 71 is detected, or an exclusion mechanism. In the case of having 60, the exclusion mechanism 60 excludes the liquid container 72 in which the metal 71 is detected from the conveyance belt 21. When there is no hindrance to the operation of the supply conveyor and the discharge conveyor connected to the conveyance belt 21 and the liquid container 72 does not fall, the conveyance belt 21 may be stopped when the metal 71 is detected.

  When the metal 71 is deposited on the bottom of the liquid container 72 due to the specific gravity of the metal 71 and the inspection object 70, the metal detector 11 from which the upper magnet 42 is removed is used in the first embodiment. Also, the metal 71 of the inspection object 70 stored in the liquid container 72 can be detected.

  Next, a metal detection apparatus according to a fourth embodiment of the present invention will be described. FIGS. 8A and 8B are schematic external views of the metal detection device according to the fourth embodiment, in which FIG. 8A is a top view and FIG. 8B is a partially see-through side view as viewed from the entrance side of the transfer pipe. The metal detection device 11 according to the first embodiment and the metal detection device 12 according to the second embodiment target an inspection object 70 that is a tangible object, and the metal detection device 13 according to the third embodiment Although the liquid stored in the non-magnetic liquid container 72 is the inspection object as the inspection object 70, the metal detection device 14 of the fourth embodiment uses the fluid flowing in the non-magnetic transfer pipe 25 as the inspection object. 70 is the inspection target. The non-magnetic transfer pipe 25 is a glass or plastic pipe, but aluminum is a non-magnetic material even if it is a metal, so the aluminum pipe can also be applied to detect a metal in the fluid.

  The diameter of the transfer pipe 25 is limited by the detection ability of the magnetic detection sensor 31, and the diameter of the transfer pipe 25 is within 100 mm, assuming that the detection ability capable of obtaining high accuracy of the magnetic detection sensor 31 planned to be used here is 50 mm. It becomes. If the detection capability of the magnetic detection sensor 31 is improved, the corresponding diameter can be obtained.

  The fluid that is the inspection object 70 is supplied to the transfer pipe 25 from a supply pipe (not shown) connected to the left connection flange 26, and metal detection is performed while moving in the transfer pipe 25, so that the right connection flange 27. It is discharged to a discharge pipe (not shown) connected to.

  Outside the front half of the transfer pipe 25, a plurality of magnets of the magnetism device 40 are annularly arranged so as to surround the outer periphery of the transfer pipe 25. Although six magnets are used in FIG. 8, it is not limited to this.

  Outside the rear half of the transfer pipe 25, a plurality of sensor boxes 37 of the detection unit 30 are connected to the transfer pipe 25 so that the MI sensor element 34 of the magnetic detection sensor 31 of the detection unit 30 is close to the outer periphery of the transfer pipe 25. It is arranged in an annular shape so as to surround the outer periphery. Although six sensor boxes 37 are used in FIG. 8, the present invention is not limited to this. Here, a detection lamp 52 for notifying metal detection is provided on the sensor box 37 at the highest position. However, the position of the detection lamp 52 is not limited to this, and is a place where the inspector can easily see. If it is. The plurality of magnets of the magnetic device 40 and the plurality of sensor boxes 37 of the detection unit 30 are held on the transfer pipe 25 by holding members (not shown).

  Although not shown in FIG. 8, an automatic switching valve is provided between the connection flange 27 and the discharge pipe, and fluid is always flowing through the discharge pipe, but the magnetic detection sensor 31 is the inspection object 70. When the metal 71 is detected inside a certain fluid, it is desirable that the automatic switching valve is temporarily switched under the control of the control unit 50 and the portion where the metal 71 of the fluid is detected is discharged to another path. Alternatively, the flow may be stopped and the fluid in the transfer pipe may be discharged to the outside.

  As described above, the fluid that is the inspection object 70 supplied to the entrance of the transfer pipe 25 from the supply pipe connected to the connection flange 26 of the transfer pipe 25 that is the moving device 20 is sent through the transfer pipe 25. First, it passes between a plurality of magnets arranged in an annular shape surrounding the transfer pipe 25. When the metal 71 is mixed in the fluid, the metal 71 becomes magnetized, and surrounds the next transfer pipe 25 in an annular shape. When the metal 71 is detected by the magnetic detection sensors 31 incorporated in the plurality of sensor boxes 37 arranged, and the magnetism of the metal 71 is detected, the detection lamp 52 is turned on to allow the inspector to flow the fluid. And the fluid portion in which the metal 71 is detected is removed, or if an automatic switching valve is provided, the flow path is switched to eliminate the fluid in which the metal 71 is detected. That.

  Next, a metal detection apparatus according to a fifth embodiment of the present invention will be described. FIG. 9 is a schematic external view of a metal detection device according to a fifth embodiment, where (a) is a top view and (b) is a side view. The metal detection device 11 according to the first embodiment and the metal detection device 12 according to the second embodiment target an inspection object 70 that is a tangible object, and the metal detection device 13 according to the third embodiment The liquid stored in the nonmagnetic liquid container 72 is the inspection object 70, and the metal detection device 14 of the fourth embodiment uses the fluid flowing in the nonmagnetic transfer pipe 25 as the inspection object 70. In the metal detector 15 of the fifth embodiment, an inspection object 70 that is a tangible object that slides on the slide table 28 is an inspection object, and the inspection object 70 is placed in a non-magnetic tray 73. It may be. The inspection object 70 is described as sliding between the magnetism device 40 and the sensor box 37 which are pushed up on the slide base 28 by the inspector and are standing upright on both sides, but a pusher (not shown) slides. The inspection object 70 provided on the entrance side of the table 28 may be slid on the sliding table 28 directly or the inspection object 70 placed on the tray 73 may be slid. It is used as a simple metal inspection apparatus with a low cost when the inspection object quantity is small with a small inspection object 70.

In FIG. 9B, h ₅ is the maximum height of the inspection object 70, and can be set according to the height of the inspection object 70 by changing the heights of the magnetism device 40 and the detection unit 30. On the other hand, the width of the direction perpendicular to the sliding direction of the inspection object 70 is limited by the detection capability of the magnetic detection sensor 31, and the detection capability for obtaining high accuracy of the magnetic detection sensor 31 planned to be used here is 50 mm. Then, the width W ₁ in the direction orthogonal to the sliding direction is within 100 mm. If the detection capability of the magnetic detection sensor 31 is improved, the corresponding width W ₁ can be obtained.

  The inspection object 70 or the tray 73 on which the inspection object 70 is placed is supplied onto the slide table 28 from the left side of FIG. 9, and metal detection is performed during movement and the metal object is pushed out to the right side.

  On the both sides of the front half of the slide base 28, the right magnet 43 and the left magnet 44 of the magnetism device 40 are supported by the slide base 28 and provided vertically so as to be close to the sliding inspection object 70. ing. Here, a detection lamp 52 for notifying metal detection is provided on the right magnet 42, but the position of the detection lamp 52 is not limited to this, and may be any place where the inspector can easily see.

  On both sides of the rear half of the slide table 28, the MI sensor elements 34 and 35 of the magnetic detection sensor 31 of the detection unit 30 are supported by the slide table 28 so as to be close to the inspection object 70 to be slid. A sensor box 37 is provided in the vertical direction. Further, a proximity switch 53 that detects the entry of the detection object 70 is provided in the vicinity of the upstream side of the sensor box 37.

  In FIG. 9, the exclusion mechanism 60 is not provided, but the exclusion mechanism 60 as described in the first embodiment may be provided on the upper surface of the slide base 28 downstream of the sensor box 37. In this case, the guide stopper 61 that is operated by electricity or air pressure is always at a position away from the slide 28, and when the magnetic detection sensor 31 detects the metal 71 in the inspection object 70, it is controlled by the control unit 50. It rotates to the top of the slide 28, and the inspection object 70 in which the metal 71 is detected is fed into the collection box. Since the inspector places the inspection object 70 on the slide base 28 and slides the slide base 28 and visually recognizes the detection of the metal 71 by the detection lamp 52, the inspector detects the metal 71 detected. Since the object 70 may be removed, it is not usually necessary to provide the exclusion mechanism 60.

  As described above, the inspection object 70 placed on the entrance side of the slide base 28 which is the moving device 20 or the inspection object 70 placed on the tray 73 is pushed on the slide base 28 and slides. First, when the metal 71 passes through the right magnet 43 and the left magnet 42 of the magnetizing device 40 and the metal 71 is mixed in the inspection object 70, the metal 71 is magnetized, and the sensor box 37 of the next detection unit 30. When the metal 71 is detected by the magnetic sensor 31 built in the sensor 71 and the magnetism of the metal 71 is detected, the detection lamp 52 is turned on, and the inspector moves the inspection object 70 in which the metal 71 is detected. When the removal mechanism 60 is provided, the removal mechanism 60 removes the inspection object 70 in which the metal 71 is detected from the slide base 28.

It is a typical block block diagram of the metal detection apparatus of the 1st to 5th embodiment of this invention. It is a typical side view of the sensor box of FIG. It is typical sectional drawing of the magnetic detection sensor of FIG. It is a control circuit block diagram of the control part 50 of FIG. It is a typical external view of the metal detection apparatus of 1st Embodiment. (A) is a top view. (B) is a partial cross-sectional side view. It is a typical external view of the metal detection apparatus of 2nd Embodiment. (A) is a top view. (B) is a partial cross-sectional side view. It is a typical external view of the metal detection apparatus of 3rd Embodiment. (A) is a top view. (B) is a partial cross-sectional side view. It is a typical external view of the metal detection apparatus of 4th Embodiment. (A) is a top view. (B) is the partial see-through | perspective side view seen from the entrance side of the transfer pipe. It is a typical external view of the metal detection apparatus of 5th Embodiment. (A) is a top view. (B) is a side view.

Explanation of symbols

10, 11, 12, 13, 14, 15 Metal detection device 20 Moving device 21 Conveyor belt 22 Conveyor drive unit 23 Tension roller 24 Frame 25 Transfer pipe 26, 27 Connection flange 28 Slide table 30 Detection unit 31 Magnetic detection sensor 32 First 1 sensor part 33 2nd sensor part 34, 35 MI sensor element 37 sensor box 37a magnetic shield material 38 signal line 40 magnetism device 41 lower magnet 42 upper magnet 43 right magnet 44 left magnet 45 annular magnetism device 50 control unit 51 control Panel 52 Detection lamp 53 Proximity switch 60 Exclusion mechanism 61 Guide stopper 62 Collection box 70 Inspection object 71 Metal 72 Liquid container 73 Tray 81a, 81b High-pass filter 82a, 82b Amplifier 83 Subtraction circuit 84 Low-pass Filter 85 comparator 86a positive threshold 86b negative threshold 87 pulse generator

Claims (12)

A metal detection device for detecting metal remaining in an inspection object,
Means for moving the inspection object;
A magnetizing device that is provided in the first half of the moving means and magnetizes the metal remaining inside the moving inspection object;
A detection unit that is provided at a position close to the inspection object to be moved in the latter half of the moving means and detects the magnetism of the metal remaining inside;
A control unit for detecting the presence or absence of the metal remaining in the inspection object from the measurement result of the detection unit;
A proximity switch that is provided in the vicinity of the entry side of the inspection object and detects the entry of the inspection object to the detection unit;
The detection unit includes a magnetic sensor element including a first magnetic impedance sensor disposed so as to be in the vicinity of the inspection object that moves close to the detection unit by the moving unit, and the inspection object A magnetic detection sensor for accommodating both magnetic sensor elements at a close interval of 10 to 50 mm while forming a pair with a second magnetic sensor element composed of the same magnetic impedance sensor disposed so as to be located away from A plurality of magnetic detection sensors are arranged in a row in a direction orthogonal to the moving direction of the inspection object that moves for detection of the metal, and the magnetic detection sensors are connected to the inspection object. The magnetic shield material is stored on the entire surface excluding the proximity surface of
The control unit causes the proximity switch to output a metal detection signal for a passing time at the detection unit of the inspection object by detecting the entry of the inspection object, and the first magnetic sensor element of each of the magnetic detection sensors. The metal detection device calculates a difference between the output of the second magnetic sensor element and the output of the second magnetic sensor element, and outputs a metal detection signal when the difference value exceeds a predetermined threshold value. The metal detection device according to claim 1 , wherein the magnetic detection sensors are arranged in a line 10 to 30 mm apart from each other.   The metal detection device according to claim 1, further comprising metal detection alarm means for outputting an alarm in response to the output of the metal detection signal.   Proximity switch for detecting the entry of the inspection object to the detection unit is provided in proximity to the inspection object on the entry side of the detection unit, and the control unit performs the inspection based on the operation of the proximity switch. The metal detection apparatus according to claim 1, wherein the metal detection signal is output only when an object is in a magnetic detection range of the detection unit. The inspection object is a tangible object, the moving means is a belt conveyor, and the magnetizing device and the detection unit are arranged close to the lower surface of the nonmagnetic belt on which the inspection object of the belt conveyor is mounted. The metal detection device according to any one of claims 1 to 4 , wherein the metal detection device is provided. The metal detection device according to claim 5 , wherein the magnetism device is also disposed on an upper side of the inspection object that is moved by the belt conveyor. The object to be inspected is a tangible object, the moving means is a belt conveyor, and the magnetizing device and the detection unit are both close to the lower surface of the non-magnetic belt on which the object to be inspected is mounted. The metal detection device according to any one of claims 1 to 4 , wherein the metal detection device is disposed at a position where the inspection object is moved and an upper side of the inspection object moved by the belt conveyor. The inspection object is a liquid stored in a non-magnetic container, and the moving means is a non-magnetic conveyor for moving the container storing the inspection object in a horizontal direction in a vertical state, and the magnetic device and the detection unit are arranged in a vertical direction so as to approach the left and right of the container containing the respective said inspection object moving on the conveyor, to any one of claims 1 to 4 The metal detection apparatus as described. The object to be inspected is a liquid, the moving means is a nonmagnetic pipe through which the liquid flows, and the magnetizing device and the detection unit are respectively arranged on the upstream side and the downstream side of the nonmagnetic pipe. The metal detection device according to any one of claims 1 to 4 , wherein the metal detection device is disposed adjacently so as to surround a magnetic pipe. The inspection object is a tangible object, the moving means is a flat surface on which the inspection object can be slid along a predetermined path, and the magnetism device and the detection unit slide on the flat surface, respectively. 5. The metal detection device according to claim 1, wherein the metal detection device is arranged in a vertical direction so as to be close to the inspection object on the left and right of the inspection object. The metal detection apparatus according to claim 10 , wherein the inspection object is mounted on a nonmagnetic container, and the container slides on the plane. Moving means of the inspection object, claim the inspection object which the metal has been detected, branched from the mobile unit as a main with a separating means for moving, according to claim 1, claim 5, claim 7 The metal detection device according to any one of 10 .

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