Foreign matter detecting device

Abstract

To provide a foreign matter detection device capable of suppressing generation of noise and appropriately detecting foreign matter.SOLUTION: This device is provided with a flow passage part for flowing a detecting object being powder / grain / liquid, a hopper part 30 for inputting the detecting object to the flow passage part, a stacker part 40 for receiving the detecting object flowing in the flow passage, and a magnetic force change detecting means 14 arranged in the flow passage part, and the flow passage part is inclined in response to fluidity of the detecting object.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a foreign matter detector for detecting foreign matter such as magnetic or non-magnetic material, metal, or the like, in a detection target. [Background technology]

[0002] The applicant of the present application has proposed foreign object detection devices such as those described in Japanese Patent Application Laid-Open No. 2015-210235 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2016-180701 (Patent Document 2). However, in a device that drops a detection target 201 while a cylindrical body 100 is upright as shown in FIG. 1 , particles of the detection target 201 come into contact with each other during the drop, causing friction, or particles of the detection target 201 come into contact with a wall 103 of the cylindrical body 100, causing friction, generating static electricity and causing the particles to grow. When a clump 202 of larger particles falls while contacting the wall 103 of the cylindrical body 100 or falls through the cylindrical body 100, the clump 202, which is larger than the original particle of the detection target 201, moves, causing the signal detected by the sensor to increase, resulting in an output signal similar to that when a foreign object is present in the detection target 201.

[0003] Figure 2 shows the detection signal obtained by a conventional foreign object detection device. That is, even when a detection object 201 without any foreign object is dropped, the overall amplitude increases due to noise, and an output signal similar to that obtained when a foreign object is present in the detection object 201 is obtained.

[0004] Although not used for detecting foreign objects, devices that tilt or vibrate a conveying path are known. For example, Patent Document 3 discloses a powder supplying device that includes a chute that is pivotally mounted below a powder supplying conduit and receives powder that falls from the powder supplying conduit and drops it toward a container. This powder supplying device is equipped with a swinging means that continuously varies the tilt angle of the chute. With a powder supplying device configured as described above, the powder that falls from the powder supplying conduit passes through a conveying path whose tilt angle is continuously varied by the chute, and is uniformly filled into the container.

[0005] Patent Document 4 discloses a powder supplying device that receives powder supplied from a supply hopper on a receiving plate and sends it to an inclined gutter. The receiving plate is vibrated by a vibrating device, imparting a moving force to the powder. The gap between the tip of the receiving plate and the inclined gutter is set extremely narrow, and the granules in this gap gradually move into the inclined gutter as if they are connected together to form a bridge. As a result, regardless of the vibrations caused by the vibrating device, the granules flow down the inclined gutter without bouncing around at the gap.

[0006] Furthermore, Patent Document 5 discloses a heat treatment device for metal powder in which a sloping surface serving as a powder flow path within a cylindrical body is heated to a predetermined temperature, causing the metal powder to flow along the sloping surface under its own weight. This device has a metal powder inlet at the top of the cylindrical body and an outlet at the bottom. The cylindrical body has a gently sloping surface through which the metal powder can flow under its own weight. It is equipped with a means for heating the sloping surface to a high temperature, and the cylindrical body is filled with atmospheric gas. Furthermore, it is configured with a vibration means for vibrating the sloping surface. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-210235 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-180701 [Patent Document 3] Japanese Utility Model Application Publication No. 3-115626 [Patent Document 4] Japanese Utility Model Application Publication No. 60-183733 [Patent Document 5] Japanese Patent Application Publication No. 60-234901 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to improve the current state of conventional foreign object detection devices as described above, and its purpose is to provide a foreign object detection device that can suppress noise generation and perform appropriate foreign object detection, even for detection targets such as powders, granules, and liquids. [Means for solving the problem]

[0009] The foreign object detection device according to the embodiment comprises a flow path section for flowing a detection object, which may be a powder, granules, or liquid; a hopper section for feeding the detection object into the flow path section; a stacker section for receiving the detection object that has flowed through the flow path; and a magnetic force change detection means provided in the flow path section, and is characterized in that the flow path section is inclined according to the fluidity of the detection object.

[0010] In the foreign object detection device according to the embodiment, the flow path portion is configured by a cylindrical body or a gutter body.

[0011] The foreign object detection device according to the embodiment is characterized in that it is provided with a vibration means for vibrating the flow path portion or the hopper portion.

[0012] The foreign object detecting device according to the embodiment is characterized in that it is provided with two vibration means for vibrating the flow path portion and the hopper portion.

[0013] The foreign object detecting device according to the embodiment is characterized in that the vibration frequencies of the two vibration means are different.

[0014] In the foreign object detecting device according to the embodiment, the inner wall of the flow path portion is coated or processed to reduce friction.

[0015] The foreign object detecting device according to the embodiment is characterized by including an inclination angle adjusting mechanism that changes the inclination angle of the flow path portion. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing the configuration of a conventional foreign object detection device. [Figure 2] FIG. 10 is a diagram showing a detection signal obtained by a conventional foreign object detection device. [Figure 3] FIG. 1 is a configuration diagram of a first embodiment of the present invention. [Figure 4] 4A and 4B are diagrams showing detection signals obtained by the foreign object detection device of the present embodiment. [Figure 5] FIG. 10 is a configuration diagram of a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] A foreign object detection device according to an embodiment of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same components are designated by the same reference numerals, and duplicate explanations will be omitted. Figure 3 shows a configuration diagram of a foreign object detection device according to a first embodiment of the present invention.

[0018] The foreign object detection device generates a magnetic field using, for example, neodymium magnets 11 and 12. These neodymium magnets 11 and 12 constitute magnetic field generating means that generate the magnetic field. Note that the magnetic field generating means is not limited to permanent magnets, and may also be electromagnets.

[0019] A cylindrical body 13 is provided in the magnetic field as a flow path for the detection object 20, which may be a powder, granules, or liquid. The detection object 20 may be a powder, granules, or liquid, and may contain foreign matter such as solid particles. The cylindrical body 13 may be made of metal, resin, glass, ceramic, paper, or other materials. The shape of the cylindrical body 13 may be a cylinder, a polygonal cylinder, or other shape. The cylindrical body 13 is disposed elongated and arranged at a predetermined inclination angle relative to the horizontal plane depending on the fluidity of the detection object 20, allowing the detection object 20 to move along the inclination. This cylindrical body 13 constitutes a moving means for moving the detection object 20 so that it slides in a direction perpendicular to the magnetic field lines generated by the magnetic force generating means. A hopper unit 30 for introducing the detection object 20 may be provided at the inlet side of the cylindrical body 13, and a stacker unit 40 for receiving the detection object 20 may be provided at the outlet side of the cylindrical body 13.

[0020] The fluidity can be explained as follows. The fluidity of powders and granular materials is a property that indicates the ease with which the powder moves, and is said to be affected by adhesive force, static friction, kinetic friction, gravity, inertial force, packing rate, coordination number, particle size, particle shape, surface roughness, particle density, etc. Evaluation methods include angle of repose measurement and outflow velocity measurement (orifice flow, Carney flow, etc.). In the case of liquids, fluidity and viscosity are inversely proportional, and fluidity can be evaluated by measuring viscosity. Viscosity can be measured using capillary viscometers (Ostwald method, Ubbelohde method, etc.), rotational viscometers (spindle method, cone method, etc.), and vibration viscometers (tuning fork type, diaphragm type, etc.).

[0021] The flow path can be formed by a gutter instead of the cylindrical body 13 as a flow path for flowing the detection target 20. The cross-sectional shape of the gutter perpendicular to the flow path direction is not limited to a straight line, but can be a U-shape, a V-shape, a semicircular shape, a rectangular shape with an open top, an inverted trapezoidal shape, or the like.

[0022] Numeral 14 denotes magnetic force change detection means for detecting magnetic force changes. Magnetic force change detection means 14 can be attached to the side wall of cylindrical body 13 in the magnetic field, or can be provided in close proximity to the side wall of cylindrical body 13. There are no particular limitations on the magnetic force change detection means 14 as long as it is a sensor that can detect a direct magnetic force change due to the movement of magnetic metal or a magnetic force change due to eddy currents caused by the movement of non-magnetic metal, and a coil, an MI sensor, an MR sensor, a Hall element, etc. can be used.

[0023] Numeral 15 denotes a magnetic shielding case, which houses the neodymium magnets 11 and 12, the cylindrical body 13, and the magnetic force change detection means 14. The shielding case 15 has a hole 16 that surrounds the end of the cylindrical body 13. The magnetic field remains within the shielding case 15, and when the neodymium magnets 11 and 12 are arranged with the north pole at the bottom and the south pole at the top as shown in Figure 3, the magnetic field is directed generally from bottom to top, including within the cylindrical body 13. This magnetic field direction is merely an example, and there are no particular limitations as long as the magnetic force change detection means 14 can detect magnetic force. The shape of the shielding case 15 can be a cube, a rectangular parallelepiped, a cylinder, a polygonal cylinder, or a sphere.

[0024] A required number of signal lines 17 are connected to the magnetic force change detection means 14, and the signal lines 17 are connected to a measurement circuit 50 provided outside the shielding case 15. In the measurement circuit 50, the signal detected by the magnetic force change detection means 14 is amplified, converted into digital data that can be processed by, for example, a computer, and sent to a processing device 60 constituted by a computer or the like.

[0025] In this embodiment, the cylindrical body 13 that penetrates horizontally through the housing-like shielding case 15 is configured as one unit with the shielding case 15. The shielding case 15 is placed and fixed on the inclined surface of the base 10, which has an inclined surface with a predetermined inclination angle formed on the upper surface. The predetermined inclination angle is a predetermined angle that corresponds to the fluidity of the detection target 20, so that the detection target 20 flows and moves as if sliding within the cylindrical body 13, and therefore no static electricity is generated due to friction between the particles that make up the detection target 20, and the detection target 20 does not grow into large clumps.

[0026] In this embodiment, a first vibration means 70A that vibrates the flow path portion (cylindrical body 13) and a second vibration means 70B that vibrates the hopper portion 30 are provided. The first vibration means 70A and the second vibration means 70B can vibrate at their own frequencies and required powers under the control of the processing device 60. Therefore, even with this vibration, the detection target 20 flows and moves as if sliding within the cylindrical body 13, preventing static electricity from being generated due to friction between the particles that make up the detection target 20 and preventing the particles from growing into large clumps. To achieve a similar effect, the inner wall of the flow path portion can be coated or processed to reduce friction. Here, processing can be performed, for example, by blasting or etching, to improve fluidity.

[0027] The processing device 60 determines magnetic field fluctuations based on the detection signal sent from the measurement circuit 50 and detects foreign matter from the magnetic field fluctuations. For example, if a metallic foreign matter is present in the detection target object 20, the metallic foreign matter will be magnetized in the cylindrical body 13 inside the shield case 15, and will move toward and away from the magnetic force change detection means 14. At this time, the magnetic field near the magnetic force change detection means 14 will be disturbed, and the magnetic field value will fluctuate. In such a state, it is possible to detect the presence of a metallic foreign matter.

[0028] Alternatively, a dummy detection object 20 containing no metal is placed from the hopper 30 into the cylindrical body 13 to determine the magnetic field value. Next, an actual detection object 20 is placed into the cylindrical body 13 to determine the magnetic field value. The presence or absence of a foreign object can be determined from the difference in the magnetic field values. Here, the measurement circuit 50 and processing device 60 can constitute a means for determining magnetic field fluctuations based on the signal detected by the magnetic force change detection means 14 and detecting foreign objects from the magnetic field fluctuations.

[0029] Furthermore, if non-magnetic metal is present in the object to be detected 20, the non-magnetic metal generates eddy currents in the cylindrical body 13 inside the shield case 15 due to a sudden change in the magnetic field applied to the non-magnetic metal, and these eddy currents generate a magnetic field. At this time, the magnetic field near the magnetic force change detection means 14 is disturbed, causing the magnetic field value to fluctuate. In this way, the presence of non-magnetic metal can be detected. As a result, it is possible to detect the presence of a foreign object in the object to be detected 20, regardless of whether the object is magnetic or non-magnetic. In this case, the object to be detected can be placed in the cylindrical body 13 without any foreign object present, the magnetic field value can be obtained, and the difference between this and the actual object to be detected can be calculated to detect the foreign object.

[0030] When air bubbles are mixed in as foreign matter in the detection object 20, such as powder, the magnetic permeability of the air bubbles, which are foreign matter, differs from that of other substances. The powder or the like, which has portions with different magnetic permeabilities, moves inside the cylindrical body 13. The magnetic flux tends to gather in areas with high magnetic permeability. This disrupts the magnetic field near the magnetic force change detection means 14, causing the magnetic field value to fluctuate. In such a state, it is possible to detect that air bubbles are mixed in as foreign matter in the detection object 20, such as powder.

[0031] The detection signal obtained by the foreign object detection device of this embodiment is shown in Figure 4. As is clear from comparison with the detection signal obtained by the conventional foreign object detection device shown in Figure 2, the overall amplitude is small, and the portions where the amplitude is increased due to foreign objects can be easily detected.

[0032] 5 shows a configuration diagram of a foreign object detection device according to the second embodiment. In this embodiment, a rotation mechanism 81 made up of a shaft and bearings is provided on one side of the housing that constitutes shield case 15 and on one corresponding side of the rectangular parallelepiped of base 10, creating a configuration that allows shield case 15 to rotate freely around this shaft.

[0033] A vertically moving rod 82 is provided vertically at a position far from the rotating mechanism 81 on the surface of the base 10 on which the rotating mechanism 81 is provided, so that its tip abuts against the underside of the shield case 15. A drive unit 83 that drives the vertically moving rod 82 to move it up and down is provided on the base 10. The vertically moving rod 82 and the drive unit 83 form an inclination angle adjustment mechanism that changes the inclination angle of the flow path section. For example, the vertically moving rod 82 can be formed by the rack of a rack and pinion, and the drive unit 83 can be formed by a pinion and a motor that rotates the pinion. Alternatively, the vertically moving rod 82 can be formed by the worm shaft of a worm and worm wheel, and the drive unit 83 can be formed by a motor that rotates the worm wheel.

[0034] The foreign object detection device of this embodiment makes it possible to change the inclination angle of the flow path section, and to perform processing at an appropriate inclination angle even when there is a change in the fluidity of the detection object 20, which may be a powder, granules, or liquid.

[0035] In the above embodiment, two vibration means 70A and 70B are provided to vibrate the flow path section and the hopper section 30, but either the vibration means 70A or the vibration means 70B may be provided. [Explanation of symbols]

[0036] 10 Foundations 11, 12 Neodymium magnet 13 Cylinder 14 Magnetic force change detection means 15 Shielding case 16 holes 17 Signal line 20 Object to be detected 30 Hopper section 40 Stacker section 50 Measurement circuit 60 Processing equipment 70A First vibration means 70B Second vibration means 81 Rotating mechanism 82 Vertical movement rod 83 Drive unit

Claims

1. a flow path for flowing a detection target, such as a powder, particle, or liquid; a hopper portion for introducing the detection object into the flow path portion; a stacker unit that receives the detection target object that has flowed through the flow path; a magnetic force change detection means provided in the flow path portion; Equipped with A foreign matter detecting device, wherein the flow path portion is inclined in accordance with the fluidity of the object to be detected.

2. 2. The foreign object detecting device according to claim 1, wherein the flow path portion is formed of a cylindrical body or a gutter body.

3. 2. The foreign matter detecting device according to claim 1, further comprising a vibration means for vibrating the flow path portion or the hopper portion.

4. 2. The foreign matter detecting device according to claim 1, further comprising two vibration means for vibrating the flow path portion and the hopper portion.

5. 5. A foreign object detecting device according to claim 4, wherein the vibration frequencies of the two vibration means are different.

6. 2. The foreign object detecting device according to claim 1, wherein the inner wall of the flow path is coated or processed to reduce friction.

7. The foreign object detecting device according to claim 1, further comprising an inclination angle adjusting mechanism for changing the inclination angle of the flow path portion.

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