Strong magnetic separation equipment and method for plastic fragments of multi-stage gradient magnetic field

Abstract

The invention relates to the technical field of plastic separation, in particular to strong magnetic separation equipment and method for plastic fragments of a multi-stage gradient magnetic field. The strong magnetic separation equipment comprises a rack, a driving roller and a redirection roller are rotationally arranged on the rack, and the driving roller and the redirection roller are connected through a conveying belt; a first magnet set located between the driving roller and the redirection roller is arranged on the rack, a second magnet set is arranged in the redirection roller, and a plurality of stirring pieces which are located above the first magnet set and can adjust the stirring force are arranged on the rack; impurities attached to plastic can be removed through the cleaning part, meanwhile, plastic fragments and magnetic impurities are continuously stirred to move through the stirring part, the different magnetic impurities are adsorbed in the corresponding magnetic separation areas, the problem that the single magnetic field intensity cannot meet the magnetic impurity separation requirement of different magnetic intensities is solved, and the magnetic separation efficiency is improved. Therefore, weak magnetic impurities are not firmly adsorbed, and strong magnetic impurities are difficult to thoroughly strip.

Description

Technical Field

[0001] This invention relates to the field of plastic sorting technology, and in particular to a strong magnetic sorting device and method for plastic fragments using a multi-level gradient magnetic field. Background Technology

[0002] With the rapid development of the waste plastic recycling industry, the removal of magnetic impurities from crushed plastic fragments has become a key step in improving the quality of recycled plastics. Currently, the sorting of magnetic impurities in plastic fragments typically uses a combination of conveyor belts and conveyor rollers. Permanent magnets or electromagnets are installed inside the conveyor rollers at the discharge end to attract the magnetic impurities in the plastic fragments. After attraction, the plastic fragments are collected into corresponding collection hoppers, while the magnetic impurities are scraped off by scrapers after moving to the bottom of the belt and fall into the corresponding collection components, thus completing the separation of plastic fragments from magnetic impurities.

[0003] However, the existing device has the following problems during use. First, when the plastic fragments enter the conveyor belt, the magnetic particulate impurities contained in the plastic fragments are not adsorbed. As a result, during the continuous conveying of plastic fragments, the magnetic particulate impurities are moved to the outside or scattered on the plastic fragments due to airflow and other factors. They fall on the plastic fragments in the subsequent process, making it impossible to effectively separate the magnetic particulate impurities. In addition, some plastic fragments have magnetic particles adhering to them. During the conveying process, the particles may be too small, resulting in insufficient adsorption force, and they may fall into the corresponding collection hopper with the plastic fragments. Or, when the magnetic impurities are large, they may be attracted by the magnet and fall into the magnetic impurity collection component when scraped off, resulting in incomplete separation and affecting the separation effect and quality.

[0004] In practical use, it was found that although the vibrating feeder can initially restrict magnetic particulate impurities when conveying plastic fragments, and the cleaning unit removes the magnetic impurities adhering to the plastic fragments, followed by adsorption of magnetic impurities by the first and second magnet groups, in actual use, different types of magnetic impurities require magnetic fields of different strengths to adsorb the corresponding magnetic impurities. However, existing technologies usually use magnets of a single magnetic field strength to remove magnetic impurities. If only an excessively strong magnet is used, it is easy to cause over-adsorption, which cannot achieve the function of grading and sorting. This results in impurities of different magnetic properties being mixed together, making them unrecyclable and easily reducing the purity of the refined material and the sorting accuracy. Furthermore, the strong magnetic field causes fine iron powder to quickly agglomerate into large clumps, which encapsulate the plastic fragments, forming a "magnetically coated plastic" situation, with an outer layer of iron and an inner layer of plastic, which cannot be separated later. Moreover, the ultra-strong magnetic field requires a larger permanent magnet, making maintenance difficult.

[0005] The problems summarized above are as follows: First, a single magnetic field strength cannot meet the sorting requirements of magnetic impurities with different magnetic intensities, resulting in weak magnetic impurities not being firmly adsorbed and strong magnetic impurities being difficult to completely remove. Excessive magnetic field strength also leads to the adsorption of too many non-target plastic particles, reducing sorting purity. Second, materials tend to accumulate on the conveyor belt, with some magnetic impurities covered by plastic fragments, preventing them from being fully exposed to the magnetic field and causing missed selection. The separation effect is particularly poor for fine magnetic impurities (such as fine copper wires and magnetic dust), requiring secondary manual sorting, which is inefficient and costly. Third, existing equipment lacks an effective magnetic impurity guiding mechanism, resulting in mixed collection of different magnetic impurities, necessitating additional grading processes and extending the processing time. Furthermore, the lack of isolation between magnetic field areas easily leads to magnetic field interference, further reducing sorting accuracy.

[0006] In summary, existing magnetic separation equipment for plastic fragments suffers from technical bottlenecks such as uniform magnetic field strength, low precision in separating magnetic impurities, poor material dispersion, and lack of dynamic adjustment capabilities, failing to meet the demands of the waste plastic recycling industry for efficient, precise, and graded separation. Summary of the Invention

[0007] The purpose of this invention is to provide a strong magnetic sorting device and method for plastic fragments using a multi-level gradient magnetic field, which solves the problems of weak magnetic impurities not being firmly adsorbed and strong magnetic impurities being difficult to completely remove due to the single magnetic field strength of existing sorting devices.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A high-intensity magnetic sorting device for plastic fragments using a multi-level gradient magnetic field includes a frame. A drive roller and a redirecting roller are rotatably mounted on the frame and connected by a conveyor belt. A first magnet group is positioned between the drive roller and the redirecting roller on the frame. A second magnet group is positioned inside the redirecting roller. The first and second magnet groups are divided along the axial direction of the redirecting roller into multiple magnetic separation zones with progressively increasing magnetic field strengths. Multiple actuating elements are positioned above the first magnet group on the frame and are adjustable in actuation force. When a plastic fragment moves above the first magnet group, the actuating elements actuate the magnetic impurities, causing impurities of different magnetic properties to be adsorbed into the corresponding magnetic separation zones of the first magnet group on the conveyor belt.

[0010] Preferably, the frame is equipped with a mounting plate located between the drive roller and the redirecting roller, the first magnet group is mounted on the mounting plate, the mounting plate is equipped with a first magnet on the side near the drive roller, the first magnet and the first magnet group are in a non-magnetic area, the frame is provided with two flexible cleaning components that can rotate in opposite directions, and the cleaning components are in contact with the outer surface of the conveyor belt.

[0011] Preferably, the first magnet group and the second magnet group have multiple different magnetic separation zones corresponding to each other. The first magnet group and the second magnet group are arranged in sequence along the axial direction of the redirecting roller as a first magnetic separation zone, a second magnetic separation zone and a third magnetic separation zone with successively increasing magnetic field strength. Correspondingly, a separator is provided between the first magnetic separation zone and the second magnetic separation zone and between the first magnetic separation zone and the third magnetic separation zone to cut off the interference between different magnetic separation zones.

[0012] Preferably, a guide rail is provided on the frame, a slider is slidably provided in the guide rail, a telescopic column is provided at the bottom end of the slider, the bottom end of the telescopic column is fixedly connected to a toggle member, the bottom of the toggle member is made of flexible material, and a lead screw is rotatably provided on the frame, the lead screw is threadedly connected to the slider.

[0013] Preferably, a vibrating feeder is provided on the side of the frame near the drive roller, the discharge end of the vibrating feeder is located directly above the drive roller, and two guide elements are provided inside the vibrating feeder.

[0014] Preferably, the frame is provided with a plastic fragment discharge port on one side of the redirecting roller, and a magnetic impurity discharge port is provided on the frame below the conveyor belt. The magnetic impurity discharge port is provided with multiple scrapers corresponding to different magnetic separation zones, and the magnetic impurity discharge port is divided into multiple types according to different magnetic separation zones, so as to facilitate the separate collection of different magnetic impurities.

[0015] Preferably, two Hall sensors are provided on each of the first, second, and third magnetic separation zones of the first magnet group to detect the migration of magnetic impurities between the first, second, and third magnetic separation zones. A vision sensor is provided on the frame. The Hall sensors and the vision sensor are used together to detect whether the actuation force of the actuating component is reasonable. The detection range of the Hall sensor covers the entire area of ​​its magnetic separation zone. A controller is provided on the frame, and each Hall sensor and telescopic column is electrically connected to the controller.

[0016] A strong magnetic sorting method for plastic fragments using a multi-level gradient magnetic field includes the following steps:

[0017] S1. After starting the equipment, the position signal of magnetic impurities in the corresponding area is detected in real time by Hall sensors in each magnetic separation zone;

[0018] S2. If the location of a magnetic impurity is detected to exceed the preset boundary of the magnetic separation zone (i.e., cross-zone migration occurs), a migration detection signal is output to the controller.

[0019] S3. After receiving the migration detection signal, the controller adjusts the extension and retraction of the telescopic column connected to the actuating component in the corresponding magnetic separation zone according to the migration direction of the magnetic impurities, thereby adjusting the actuating force of the actuating component.

[0020] S4. If the magnetic impurities are within the preset boundary of the magnetic separation zone, then lock the current telescopic column extension amount; if the magnetic impurities still migrate, repeat step S3 until there is no magnetic impurity migration signal.

[0021] Preferably, the detection criteria of the Hall sensor in S2 is as follows: if the position difference of the magnetic field signal of magnetic impurities collected by two Hall sensors in the same magnetic separation zone exceeds 5 mm, or if the Hall sensors in adjacent magnetic separation zones cross-detect magnetic field signals of magnetic impurities of different magnetic grades (such as the Hall sensor in the second magnetic separation zone detecting a low magnetic impurity signal in the first magnetic separation zone), it is determined that the magnetic impurities have migrated across zones.

[0022] Preferably, step S3 includes the following steps:

[0023] S301. If the vision sensor detects that the toggle does not move the plastic, it is determined that the toggle force is too small. The vision sensor sends a signal to the controller, and the controller controls the corresponding telescopic column to extend, so that the toggle descends to increase the toggle force.

[0024] S302. If magnetic impurities migrate to a magnetic separation zone with a lower magnetic field strength (e.g., magnetic impurities in the third magnetic separation zone migrate to the second magnetic separation zone), the controller determines that the current driving force is too high, controls the telescopic column of the corresponding magnetic separation zone to reduce the extension amount, and raises the driving element to reduce the driving force.

[0025] Preferably, step S4 includes the following steps:

[0026] S401. The secondary detection of the Hall sensor needs to last for 3 to 5 seconds. If the positions of the magnetic impurities detected by the two Hall sensors are stable within the preset boundary of the magnetic separation zone during this time period, and there is no new migration signal output, then the current telescopic column extension amount is locked.

[0027] S402. If a migration signal is still detected, return to step S301 or S302 and readjust the toggle force until the magnetic impurities are stable.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. The first magnet magnetizes magnetic particulate impurities, causing them to adhere to the conveyor belt surface and preventing them from scattering to the outside. Simultaneously, the cleaning component rubs the plastic fragments, removing the magnetic impurities adhering to their surface. After entering the first and second magnet groups, the magnetic impurities are completely removed. Through the coordinated detection of Hall effect sensors and vision sensors, the controller adjusts the height of the material in real time when the actuating component moves it, moving only the magnetic impurities that need to be moved to the strong magnetic separation zone into the corresponding magnetic separation zone. This also enhances the separation effect between magnetic impurities and plastic fragments, achieving the technical effect of multi-level magnetic field in existing plastic fragment magnetic separation equipment and improving the accuracy of magnetic impurity sorting. At the same time, it solves the technical problem that the lack of dynamic adjustment capability in existing sorting equipment leads to the inability to further sort magnetic impurities. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0032] Figure 2 This is a schematic diagram of the full cross-section structure of the present invention.

[0033] Figure 3 This is a schematic diagram showing the distribution of the cleaning components and guide rails in this invention.

[0034] Figure 4 This is a schematic diagram showing the distribution of the first magnet and the first magnet group in this invention.

[0035] Figure 5 This is a schematic diagram showing the distribution of the second magnet group in this invention.

[0036] Figure 6 This is an exploded view of the guide rail and slider in this invention.

[0037] In the diagram: 1. Frame; 101. Mounting plate; 102. First magnet; 103. Non-magnetic zone; 104. Cleaning component; 105. Plastic fragment discharge port; 106. Magnetic impurity discharge port; 2. Drive roller; 201. Conveyor belt; 3. Deflector roller; 4. First magnet group; 401. First magnetic separation zone; 402. Second magnetic separation zone; 403. Third magnetic separation zone; 404. Separator; 5. Second magnet group; 6. Actuator; 601. Guide rail; 602. Slider; 603. Telescopic column; 604. Lead screw; 7. Vibrating feeder; 701. Flow guide. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] Currently, when sorting magnetic impurities in plastic fragments, a structure combining a conveyor belt 201 and a conveying roller is typically used. Permanent magnets or electromagnets are installed inside the conveying rollers at the discharge end to attract magnetic impurities in the plastic fragments. After attraction, the plastic fragments are collected into the corresponding collection hoppers, while the magnetic impurities are scraped off by scrapers after moving to the bottom of the belt and fall into the corresponding collection components, thus completing the separation of plastic fragments from magnetic impurities.

[0041] However, the existing device has the following problems during use. First, when the plastic fragments enter the conveyor belt 201, the magnetic particulate impurities contained in the plastic fragments are not adsorbed. As a result, during the continuous conveying of plastic fragments, the magnetic particulate impurities are moved to the outside or scattered on the plastic fragments due to airflow and other factors. They fall on the plastic fragments in the subsequent process, making it impossible to effectively separate the magnetic particulate impurities. In addition, some plastic fragments have particulate magnetic impurities adhering to them. During the conveying process, if the particles are small, the adsorption force may be insufficient, and they may fall into the corresponding collection hopper with the plastic fragments. Or, if the magnetic impurities are large, they may be attracted by the magnet and fall into the magnetic impurity collection component when scraped off, resulting in incomplete separation and affecting the separation effect and quality.

[0042] To resolve the above technical issues, please refer to Figures 1 to 6The first embodiment of the present invention provides a strong magnetic sorting device for plastic fragments with a multi-level gradient magnetic field. The device includes a frame 1, on which a drive roller 2 and a redirecting roller 3 are rotatably mounted. The drive roller 2 and the redirecting roller 3 are connected by a conveyor belt 201. A first magnet group 4 is disposed on the frame 1 between the drive roller 2 and the redirecting roller 3. A second magnet group 5 is disposed within the redirecting roller 3. The first magnet group 4 and the second magnet group 5 are divided along the axial direction of the redirecting roller 3 into multiple magnetic separation zones with progressively increasing magnetic field strength. Multiple actuating elements 6 are disposed on the frame 1 above the first magnet group 4 and are adjustable in actuation force. When a plastic fragment moves above the first magnet group 4, the actuating elements 6 actuate the magnetic impurities, causing impurities of different magnetic properties to be adsorbed onto the conveyor belt 201. Within the magnetic separation zone corresponding to the first magnet group 4, a mounting plate 101 is installed on the frame 1 between the drive roller 2 and the redirecting roller 3. The first magnet group 4 is mounted on the mounting plate 101. A first magnet 102 is mounted on the side of the mounting plate 101 near the drive roller 2. There is a non-magnetic zone 103 between the first magnet 102 and the first magnet group 4. Two flexible cleaning components 104 that can rotate in opposite directions are provided on the frame 1. The cleaning components 104 are in contact with the outer surface of the conveyor belt 201. A vibrating feeder 7 is provided on the side of the frame 1 near the drive roller 2. The discharge end of the vibrating feeder 7 is located directly above the drive roller 2. Two guide components 701 are provided inside the vibrating feeder 7. A plastic fragment discharge port 105 is provided on the side of the frame 1 located near the redirecting roller 3. A magnetic impurity discharge port 106 is provided on the frame 1 located below the conveyor belt 201.

[0043] During use, the vibrating feeder 7 vibrates and conveys material onto the conveyor belt 201. The vibrating feeder 7 causes the plastic fragments to vibrate, thereby separating the plastic fragments from the magnetic impurities. The separated magnetic impurities and plastic fragments enter the side of the conveyor belt 201 near the drive roller 2. Under the action of the first magnet 102, the magnetic particulate impurities that are susceptible to airflow and vibration are adsorbed onto the conveyor belt 201 in the area where the first magnet 102 is located. This prevents the magnetic particulate impurities from moving to too high a position due to airflow, which would prevent them from being dispersed to the outside or to a higher position in the next stage. Van der Waals forces (microscopic adhesion) have formed between the magnetic particulate impurities and the conveyor belt 201, preventing the magnetic impurities from spreading above the plastic fragments, which would result in poor separation and impact on the surrounding environment.

[0044] When the plastic fragments enter the non-magnetic zone 103, the magnetic microparticles are adhered to the conveyor belt 201 by van der Waals forces (microscopic adhesion), which reduces the probability of the impurities adhering to the conveyor belt 201 being moved when the two cleaning components 104 rub the plastic fragments. As a result, the magnetic impurities on the plastic fragments are cleaned off by the cleaning components 104. The part of the cleaning component 104 that contacts the outer surface of the conveyor belt 201 is made of flexible material, while the center and conveying part of the cleaning component 104 are made of rigid material.

[0045] A matching motor corresponding to the drive roller 2 is installed on the frame 1 to drive the drive roller 2 to rotate. During this process, the conveyor belt 201 moves continuously under the action of the drive roller 2 and the matching motor. The conveyor belt 201 drives the cleaned plastic fragments to move. The two cleaning components 104 are connected by gear meshing. At the same time, a first motor is set on one side of the frame 1. The first motor is coaxially fixedly connected to the outside of one of the cleaning components 104 to make the two cleaning components 104 rotate continuously in opposite directions. The first motor and the gear are not shown in the figure.

[0046] Subsequently, the plastic fragments and magnetic impurities move to the position of the first magnet group 4 under the action of the conveyor belt 201. The first magnet group 4 adsorbs the magnetic impurities mixed in with the plastic fragments. Then, the plastic fragments pass through the second magnet group 5, so that the magnetic impurities are firmly adsorbed on the conveyor belt 201. When the plastic fragments pass the side away from the drive roller 2 by the redirecting roller 3, the plastic fragments fall into the plastic fragment discharge port 105 under the action of inertial force. The sorted plastic fragments are collected by the collection device.

[0047] At this time, the magnetic impurities are still adsorbed on the outer surface of the conveyor belt 201 under the action of the second magnet group 5. As they move to the bottom of the mounting plate 101, they fall into the magnetic impurity outlet 106 under the action of the magnetic field isolated by the mounting plate 101. At the same time, in order to prevent the adhesion of van der Waals forces to the particulate magnetic impurities, the particulate magnetic impurities are scraped off by a scraper and then collected by a corresponding collection component, thereby completing the removal of magnetic impurities from the plastic fragments.

[0048] The first magnet 102 can magnetize the magnetic particulate impurities, causing them to adhere to the surface of the conveyor belt 201 and preventing the particulate magnetic impurities from flying to the outside. At the same time, the cleaning component 104 rubs the plastic fragments to remove the magnetic impurities adhering to the surface of the plastic fragments. After entering the first magnet group 4 and the second magnet group 5, the magnetic impurities are completely removed.

[0049] Example 2

[0050] In practical use, it was found that although the vibrating feeder 7 can initially restrict magnetic particulate impurities when conveying plastic fragments, and the cleaning component 104 removes the magnetic impurities adhering to the plastic fragments, and then the first magnet group 4 and the second magnet group 5 adsorb the magnetic impurities, in actual use, different types of magnetic impurities require magnetic fields of different strengths to adsorb the corresponding magnetic impurities. Existing technology usually uses a magnet with a single magnetic field strength to remove magnetic impurities, but if only an excessively strong magnet is used, it is easy to cause over-adsorption, which cannot achieve the function of grading and sorting. This results in impurities of different magnetic properties being mixed together, making them unrecyclable, and easily reducing the purity of the refined material and the sorting accuracy. In addition, the strong magnetic field causes fine iron powder to quickly agglomerate into large clumps, which encapsulate the plastic fragments, forming a "magnetically coated plastic" situation, with an outer layer of iron and an inner layer of plastic, which cannot be separated later. Furthermore, the ultra-strong magnetic field requires a larger permanent magnet, which makes maintenance difficult.

[0051] To solve the above-mentioned technical problems, based on the above embodiments, and referring to... Figures 1 to 6 The adopted technical solution includes a first magnet group 4, and multiple different magnetic separation zones of the first magnet group 4 and the second magnet group 5 corresponding to each other. The first magnet group 4 and the second magnet group 5 are sequentially set along the axial direction of the redirecting roller 3 as a first magnetic separation zone 401, a second magnetic separation zone 402, and a third magnetic separation zone 403 with successively increasing magnetic field strength. Separators 404 are provided between the first magnetic separation zone 401 and the second magnetic separation zone 402, and between the first magnetic separation zone 401 and the third magnetic separation zone 403, to cut off interference between different magnetic separation zones. A guide rail 601 is provided on the frame 1, and a slider 602 is slidably arranged inside the guide rail 601. A telescopic column 603 is provided at the bottom of the slider 602, and the bottom of the telescopic column 603 is fixedly connected to a toggle member 6. Multiple toggle members 6 are provided, and the bottom of the toggle member 6 is made of flexible material. A lead screw 6 is rotatably arranged on the frame 1. 04. The lead screw 604 and the slider 602 are connected by a threaded transmission. The magnetic impurity outlet 106 is equipped with multiple scrapers corresponding to different magnetic separation zones. The magnetic impurity outlet 106 is divided into multiple zones according to different magnetic separation zones, which facilitates the collection of different magnetic impurities. Two Hall sensors are set on the first magnetic separation zone 401, the second magnetic separation zone 402 and the third magnetic separation zone 403 on the first magnet group 4. These sensors are used to detect the migration of magnetic impurities between the first magnetic separation zone 401, the second magnetic separation zone 402 and the third magnetic separation zone 403. A vision sensor is set on the frame 1. The Hall sensor and the vision sensor are used together to detect whether the actuation force of the toggle 6 is reasonable. The detection range of the Hall sensor covers the entire magnetic separation zone. A controller is set on the frame 1. Each Hall sensor and the telescopic column 603 are electrically connected to the controller.

[0052] In actual use, after the plastic fragments are rubbed and cleaned by the cleaning component 104, they enter the area where the first magnet group 4 is located. At the same time, a second motor is installed at the end of the lead screw 604. The second motor is fixedly connected to the frame 1. The second motor drives the lead screw 604 to rotate. The lead screw 604 drives the slider 602 to move within the guide rail 601. The slider 602 drives the agitator 6 to move through the telescopic column 603, agitating the plastic fragments and magnetic impurities that have entered the area. This allows impurities with different magnetic properties to enter the corresponding magnetic separation zones. For example, the first magnetic separation zone 401 is a weak magnetic zone, which mainly adsorbs larger magnetic impurities such as iron nails. The second magnetic separation zone 402 is a medium magnetic zone, which mainly adsorbs smaller magnetic impurities such as iron filings and micro powder. The third magnetic separation zone 403 is a high magnetic zone, which mainly adsorbs micron-sized magnetic impurities, such as weakly magnetic stainless steel filings.

[0053] The number of actuating elements 6 is set to multiple, each actuating element 6 corresponding to a lead screw 604 and a corresponding connecting structure. When the actuating element 6 actuates the material, it is set along the moving direction of the conveyor belt 201 and located above the conveyor belt 201. In actual use, when the first actuating element 6 actuates, the actuating element 6 drives all plastic fragments and magnetic impurities to move. However, by detecting the magnetic field changes of the first magnetic separation zone 401, the second magnetic separation zone 402 and the third magnetic separation zone 403 by the Hall sensor, the actuating force of the actuating element 6 can only drive the plastic fragments and magnetic impurities that are not matched with the magnetic separation zone to move.

[0054] During this process, the magnetic impurities agitated by the agitator 6 are all impurities with insufficient adsorption force, and will not affect the impurities that should be located in the magnetic separation zone. That is, the magnitude of the agitation force is less than the magnitude of the adsorption force of the magnetic impurity in the magnetic separation zone. The agitation force of the subsequent agitator 6 is the same as that of the first agitator 6. They should all keep impurities of different magnetic properties falling into the corresponding magnetic separation zone and have the function of moving plastic fragments and other magnetic impurities. The vision sensor and Hall sensor are not shown in the figure.

[0055] The matching motor, first motor, second motor, vibrating feeder 7, vision sensor and Hall sensor are all electrically connected to the controller. The matching motor, first motor, second motor, vibrating feeder 7, controller, vision sensor and Hall sensor and their connection methods are all existing technologies and will not be described in detail here.

[0056] When the actuating element 6 moves the magnetic impurities in the corresponding magnetic separation zone outward, the Hall sensor detects a change in the magnetic field in the magnetic separation zone and sends a signal to the controller. The controller controls the corresponding telescopic column 603 to retract, thereby adjusting the actuating force of the actuating element 6 in real time. At the same time, the visual sensor detects whether the adjusted height of the actuating element 6 is sufficient to both move the plastic fragments normally and move the magnetic impurities into the corresponding magnetic separation zone.

[0057] This allows the actuating element 6 to both move the material and magnetic impurities, and also prevent impurities of different magnetic properties from migrating to the magnetic separation zone. As a result, when the plastic fragments fall into the plastic fragment discharge port 105, the magnetic impurities that have migrated to other magnetic separation zones are not attracted enough and fall into the plastic fragment discharge port 105 as well, resulting in poor separation effect and reduced separation accuracy between plastic fragments and magnetic impurities.

[0058] When the agitator force is insufficient, that is, when the visual sensor detects that the agitator 6 is moving the material back and forth, although it does not cause a change in the magnetic field of the magnetic impurities, and the magnetic impurities are located in the corresponding magnetic separation area, the visual sensor detects that the agitator 6 is not moving the plastic fragments back and forth, or that the amount of material moving the plastic fragments is too small, affecting the separation of the plastic fragments from the impurities and failing to move the impurities with insufficient adsorption force. This process can be detected by the Hall sensor and the visual sensor together. When the agitator force is insufficient, both send a signal to the controller, which causes the corresponding telescopic column 603 to extend, causing the bottom of the agitator 6 to drop, thereby moving the material normally.

[0059] At the same time, the Hall sensor detects and prevents the agitator 6 from moving too far downward, which could cause abnormal migration of magnetic impurities. This continuously agitates the material, allowing impurities of different magnetic properties to enter the corresponding magnetic separation zone, thus completing the precise separation of magnetic impurities and improving the effectiveness of magnetic impurity separation of plastic fragments.

[0060] By using Hall effect sensors and vision sensors in conjunction, the controller can adjust the height of the toggle component 6 in real time, thereby enabling the plastic fragments to move back and forth. This allows impurities of different magnetic properties to fall into the corresponding magnetic separation zones, achieving the technical effect of multi-level magnetic field in existing plastic fragment magnetic separation equipment and improving the accuracy of magnetic impurity separation. At the same time, it solves the technical problem that the lack of dynamic adjustment capability in existing separation equipment leads to the inability to further separate magnetic impurities.

[0061] Example 3

[0062] Based on the above embodiments, this embodiment also provides a strong magnetic sorting method for plastic fragments using a multi-level gradient magnetic field, including the following steps:

[0063] S1. After the equipment is started, the toggle 6 moves back and forth and moves the plastic fragments and magnetic impurities, and moves impurities of different magnetic properties to the corresponding magnetic separation zones. The position signals of the magnetic impurities in the first magnetic separation zone 401, the second magnetic separation zone 402 and the third magnetic separation zone 403 are detected in real time by the Hall sensors in each magnetic separation zone.

[0064] S2. If the Hall sensor in each magnetic separation zone detects that the position of the magnetic impurity exceeds the preset boundary of the magnetic separation zone (i.e., cross-zone migration occurs), the Hall sensor will output a migration detection signal to the controller.

[0065] S3. After receiving the migration detection signal, the controller adjusts the extension and retraction of the telescopic column 603 connected to the toggle 6 according to the migration direction of the magnetic impurities, thereby adjusting the toggle force of the toggle 6.

[0066] S4. If the magnetic impurities are within the preset boundary of the magnetic separation zone, lock the current extension amount of the telescopic column 603 and keep the height of the toggle member 6 unchanged; if the magnetic impurities still migrate, repeat step S3 until the magnetic impurities are stable within the corresponding magnetic separation zone.

[0067] Specifically, the detection criteria for the Hall sensor in S2 are as follows: if the position difference between the magnetic field signals of magnetic impurities collected by two Hall sensors in the same magnetic separation zone exceeds 5 mm, or if the Hall sensors in adjacent magnetic separation zones cross-detect magnetic field signals of magnetic impurities of a different magnetic grade (such as the Hall sensor in the second magnetic separation zone detecting a low magnetic impurity signal in the first magnetic separation zone), it is determined that magnetic impurities have migrated across zones.

[0068] Specifically, S3 includes the following steps:

[0069] S301. If the vision sensor detects that the toggle 6 has not moved the plastic, it is determined that the toggle force of the toggle 6 is too small. The vision sensor sends a signal to the controller, and the controller controls the corresponding telescopic column 603 to extend, so that the toggle 6 drops to increase the toggle force.

[0070] S302. If the Hall sensor detects a change in the magnetic field, and magnetic impurities migrate to a magnetic separation zone with a lower magnetic field strength (e.g., magnetic impurities in the third magnetic separation zone 403 migrate to the second magnetic separation zone 402), the controller determines that the current actuation force is too large. It controls the telescopic column 603 in the corresponding magnetic separation zone to reduce the extension amount, so that the actuating element 6 is raised to reduce the actuation force. At the same time, the visual sensor and the Hall sensor jointly detect the adjusted height of the actuating element 6 and the actuation intensity of plastic fragments and magnetic impurities, so as to adjust the height of the actuating element 6 in real time.

[0071] Specifically, S4 includes the following steps:

[0072] S401, the secondary detection of the Hall sensor needs to last for 3 to 5 seconds. If the position of the magnetic impurity detected by the two Hall sensors is stable within the preset boundary of the magnetic separation zone during this time period, and there is no new migration signal output, then the current telescopic column 603 telescopic amount is locked.

[0073] S402. If the visual sensor detects that the actuating element 6 has not moved the plastic fragment, or the Hall sensor still detects a migration signal, return to step S301 or S302 and readjust the actuating force until the magnetic impurities are stable.

[0074] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-intensity magnetic sorting device for plastic fragments using a multi-level gradient magnetic field, comprising a frame, characterized in that, The frame is equipped with a drive roller and a redirecting roller, which are connected by a conveyor belt. A first magnet group is located between the drive roller and the redirecting roller on the frame, and a second magnet group is located inside the redirecting roller. The first and second magnet groups are divided into multiple magnetic separation zones with progressively increasing magnetic field strength along the axial direction of the redirecting roller. The frame is equipped with multiple actuating elements located above the first magnet group and capable of adjusting the actuating force. When the plastic fragment moves above the first magnet group, the actuating elements actuate the magnetic impurities, so that impurities with different magnetic properties are adsorbed into the corresponding magnetic separation zones of the first magnet group on the conveyor belt.

2. The high-intensity magnetic sorting device for plastic fragments with a multi-level gradient magnetic field according to claim 1, characterized in that, The frame is equipped with a mounting plate located between the drive roller and the redirecting roller. The first magnet group is mounted on the mounting plate. A first magnet is mounted on the side of the mounting plate near the drive roller. There is a non-magnetic area between the first magnet and the first magnet group. The frame is provided with two flexible cleaning components that can rotate in opposite directions. The cleaning components are in contact with the outer surface of the conveyor belt.

3. The high-intensity magnetic sorting device for plastic fragments with a multi-level gradient magnetic field according to claim 2, characterized in that, The first magnet group and the second magnet group have multiple different magnetic separation zones corresponding to each other. The first magnet group and the second magnet group are arranged in sequence along the axial direction of the redirecting roller as a first magnetic separation zone, a second magnetic separation zone and a third magnetic separation zone with successively increasing magnetic field strength. Correspondingly, there are separators between the first magnetic separation zone and the second magnetic separation zone and between the first magnetic separation zone and the third magnetic separation zone to cut off the interference between different magnetic separation zones.

4. The high-intensity magnetic sorting device for plastic fragments with a multi-level gradient magnetic field according to claim 3, characterized in that, The frame is equipped with a guide rail, and a slider is slidably mounted inside the guide rail. A telescopic column is mounted at the bottom of the slider, and the bottom of the telescopic column is fixedly connected to a toggle component. The bottom of the toggle component is made of a flexible material. A lead screw is rotatably mounted on the frame, and the lead screw is threadedly connected to the slider.

5. The high-intensity magnetic sorting device for plastic fragments with a multi-level gradient magnetic field according to claim 4, characterized in that, A vibrating feeder is provided on the side of the frame near the drive roller. The discharge end of the vibrating feeder is located directly above the drive roller. Two guide elements are provided inside the vibrating feeder.

6. The high-intensity magnetic sorting device for plastic fragments with a multi-level gradient magnetic field according to claim 5, characterized in that, The frame is provided with a plastic fragment discharge port on one side of the redirecting roller. The frame is provided with a magnetic impurity discharge port located below the conveyor belt. The magnetic impurity discharge port is provided with multiple scrapers corresponding to different magnetic separation zones. The magnetic impurity discharge port is divided into multiple types according to different magnetic separation zones, which facilitates the separate collection of different magnetic impurities.

7. The high-intensity magnetic sorting device for plastic fragments with a multi-level gradient magnetic field according to claim 6, characterized in that, Two Hall sensors are installed on the first, second, and third magnetic separation zones of the first magnet group to detect the migration of magnetic impurities between the three zones. A vision sensor is installed on the frame. The Hall sensors and the vision sensor are used together to detect whether the actuation force of the actuating component is reasonable. The detection range of the Hall sensors covers the entire magnetic separation zone. A controller is installed on the frame, and each Hall sensor and telescopic column is electrically connected to the controller.

8. A strong magnetic sorting method for plastic fragments using a multi-level gradient magnetic field, employing the strong magnetic sorting equipment for plastic fragments using a multi-level gradient magnetic field as described in claim 7, characterized in that... Includes the following steps: S1. After starting the equipment, the position signal of magnetic impurities in the corresponding area is detected in real time by Hall sensors in each magnetic separation zone; S2. If a magnetic impurity is detected to be located beyond the preset boundary of the magnetic separation zone, a migration detection signal is output to the controller. S3. After receiving the migration detection signal, the controller controls the raising and lowering of the toggle to adjust the toggle force. S4. If no magnetic impurities migrate, lock the current telescopic column extension amount; if magnetic impurities still migrate, repeat step S3 to adjust the height of the toggle in real time.

9. The method for strong magnetic sorting of plastic fragments using a multi-level gradient magnetic field according to claim 8, characterized in that, S3 includes the following steps: S301. If the vision sensor detects that the toggle has not moved the plastic, the controller controls the toggle to descend in order to increase the toggle force. S302. If magnetic impurities migrate to the magnetic separation zone with a lower magnetic field strength, the controller determines that the current driving force is too high and controls the driving element to rise to reduce the driving force.

10. The method for strong magnetic sorting of plastic fragments using a multi-level gradient magnetic field according to claim 9, characterized in that, S4 includes the following steps: S401. If the magnetic impurities detected by the two Hall sensors do not have a new migration signal output in the corresponding magnetic separation area within the 3 to 5 seconds, then lock the height of the current toggle. S402. If a migration signal is still detected, return to step S301 or S302 and readjust the toggle force until the magnetic impurities are stable.

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