X-ray inspection equipment for sorting plastic materials in bales, RPF, small appliances, or general waste

Abstract

To provide an X-ray inspection device that can effectively prevent X-ray leakage and detect lithium ion batteries mixed in raw materials of waste plastic or compressed and packed bales. [Solution] The X-ray inspection device of the present invention comprises an inlet conveyor, an inspection conveyor, and an outlet conveyor, and is equipped with a conveyor for transporting waste plastic, an inspection box that takes in bales transported on the inlet conveyor from the entrance onto the inspection conveyor, irradiates them with X-rays to inspect for the presence of lithium-ion batteries, and discharges them from the exit onto the outlet conveyor, an entrance shutter attached to the inspection conveyor that separates the inlet conveyor and the inspection conveyor by sliding action and closes the entrance of the inspection box, and an exit shutter attached to the inspection conveyor that separates the inspection conveyor and the outlet conveyor by sliding action and closes the exit, and when X-rays are irradiated, the entrance shutter and exit shutter are kept in a closed state.

Description

[Technical Field]

[0001] The present invention relates to an X-ray inspection device that can detect lithium-ion batteries mixed in bales or waste plastic raw materials (such as RPF) and effectively prevent X-ray leakage. Lithium-ion batteries mixed in bales or waste plastics to be used as solid fuel (RPF: Refuse-derived paper and plastics densified fuel, a solid fuel made primarily from industrial waste, primarily paper and plastics that are difficult to recycle) can cause fires. Therefore, it is necessary to inspect these materials for the presence of lithium-ion batteries. Bales include blocks made by compressing and bundling plastic containers and packaging covers from households, and blocks made by compressing and bundling PET bottles that have been collected separately. [Background technology]

[0002] The plastic recycling line was established by a plant operator about 40 years ago and continues to operate to this day. Sorting is performed using color sorters, metal detectors, magnetic separators, etc., but in recent years, the inclusion of aluminum packaging and aluminum materials has made it difficult for conventional sorting machines to detect these materials, resulting in frequent fire accidents caused by the inclusion of lithium-ion batteries and button batteries. This invention proposes a new X-ray inspection device for lithium-ion batteries, which cannot be detected by conventional sorting machines.

[0003] In Patent Document 1, the present applicant proposed a foreign matter removal device for waste PET bottles that can detect foreign matter mixed in bales formed by compressing waste PET bottles. Also, in Patent Document 2, the applicant proposed a foreign matter removal device for waste plastics that detects batteries mixed in with waste plastics. According to Figure 22 of Patent Document 1, the X-ray source and line sensor are located in an X-ray room 130, which is equipped with an entrance shutter 135 and an exit shutter 136. Since the entrance shutter 135 and the exit shutter 136 are located above the roller conveyor 120 and have gaps, there are cases where they do not adequately prevent X-ray leakage.

[0004] Regarding industrial X-ray equipment, if a worker's exposure dose is 1,300 microsieverts or more, the law stipulates that a controlled area must be set up and that the work must be carried out under the supervision of a qualified person. If the dose is less than this, the setting up of a controlled area and the need for a qualified person are not required. Therefore, a target is set to keep the leakage amount from the surface of the equipment to 1 microsievert or less. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2024-002195 [Patent Document 2] Japanese Patent Application Publication No. 2024-074174 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an X-ray inspection device that can effectively prevent X-ray leakage and detect lithium ion batteries mixed in raw materials of waste plastic or compressed and packaged bales. [Means for solving the problem]

[0007] The X-ray inspection device according to the present invention is an X-ray inspection device for sorting plastic raw materials in baled goods, RPF, small household appliances, or general waste, and is equipped with: an input conveyor, an inspection conveyor, and an output conveyor for transporting waste plastic; an inspection box that takes the waste plastic transported on the input conveyor into the inspection conveyor from an entrance, irradiates it with X-rays to inspect for the presence or absence of lithium-ion batteries, and discharges it from an exit to the output conveyor; an entrance shutter that is attached to the inspection conveyor and closes the entrance by a sliding action and separates the input conveyor and the inspection conveyor; and an exit shutter that is attached to the inspection conveyor and closes the exit by a sliding action and separates the inspection conveyor and the output conveyor, and is characterized in that the entrance shutter and the exit shutter are in a closed state when the X-rays are irradiated.

[0008] The inspection conveyor is characterized in that it comprises a first inspection conveyor and a second inspection conveyor, and the X-ray source and the line sensor are arranged so that X-rays pass between the first inspection conveyor and the second inspection conveyor.

[0009] A forward / reverse switching conveyor is arranged downstream of the discharge conveyor, and discharge conveyors are provided on one side and the other side of the forward / reverse switching conveyor, so that waste plastics with lithium-ion batteries and waste plastics without lithium-ion batteries are transported in different directions.

[0010] The carry-out conveyor is characterized in that it is arranged so that the conveying direction thereof is perpendicular to the conveying directions of the forward / reverse switching conveyor and the discharge conveyor, forming a T-shape.

[0011] The discharge conveyor is arranged so that its conveying direction is parallel to the conveying directions of the forward / reverse switching conveyor and the discharge conveyor, and a right-angle rotating conveyor with rollers on its walls is provided between the discharge conveyor and the forward / reverse switching conveyor.

[0012] The waste plastic is characterized in that it is a bale product obtained by compressing and solidifying waste plastic into a block body. [Effects of the Invention]

[0013] According to the X-ray inspection device of the present invention, the conveyor is divided into an inlet conveyor, an inspection conveyor, and an outlet conveyor, and an inlet shutter and an outlet shutter are provided at the entrance and exit of the inspection box, thereby effectively preventing X-ray leakage. When X-rays are irradiated, the inlet shutter and outlet shutter are closed, preventing X-ray leakage. When the inlet shutter is closed, it separates the inlet conveyor from the inspection conveyor, and when the outlet shutter is closed, it separates the inspection conveyor from the outlet conveyor, resulting in less X-ray leakage than when the entrance and exit are covered with lead curtains.

[0014] The inspection conveyor is divided into two, the first and second inspection conveyors, and the X-rays pass between them, allowing imaging to be performed without being obstructed by the drive chains on either side of the conveyor. Bales, which are blocks of waste plastic, are approximately 1m high, so a line sensor that exceeds the width of the conveyor is required to image the entire bale, and such a long line sensor can be used.

[0015] A forward / reverse switching conveyor is located downstream of the discharge conveyor, and discharge conveyors are provided on one side and the other side of the forward / reverse switching conveyor.Based on the results of X-ray inspection, waste plastics containing lithium-ion batteries can be transported to one discharge conveyor, and waste plastics without lithium-ion batteries can be transported to the other discharge conveyor.

[0016] The conveying direction of the discharge conveyor, forward / reverse switching conveyor, and discharge conveyor are arranged so that they intersect at right angles to form a T shape, making it easy to send waste plastic to the discharge conveyor. For example, a pusher can be used to send waste plastic to the forward / reverse switching conveyor.

[0017] The conveying direction of the discharge conveyor and the forward / reverse switching conveyor and discharge conveyor are arranged so that they are parallel to each other, allowing for a slim installation space overall. Pushing baled products in a direction perpendicular to the conveyor's conveying direction creates a lot of resistance at the bottom of the baled products, so a right-angle rotating conveyor with rollers on the wall is installed between the discharge conveyor and the forward / reverse switching conveyor, and is rotated 90 degrees, allowing the products to be sent out with less resistance.

[0018] Baled products made by compressing and solidifying waste plastic into blocks are easy to transfer between conveyors. In addition, waste does not fall through the gaps in the conveyor when transferring between them. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a plan view of an X-ray inspection apparatus according to the present invention; [Figure 2] 1 is a front view of an X-ray inspection apparatus according to the present invention. [Figure 3] 3 is a cross-sectional view taken along the line AA in FIG. 2. [Figure 4] This is a cross-sectional view taken along the line AA when X-rays are irradiated from below the rear. [Figure 5] FIG. 2 is an explanatory diagram of a shutter opening and closing structure. [Figure 6] 3 is a control time chart of the X-ray inspection apparatus according to the present invention. [Figure 7] 3 is a control flowchart of the X-ray inspection apparatus according to the present invention. [Figure 8] This is a plan view showing the addition of a forward / reverse switching conveyor and a discharge conveyor that sorts bales based on whether or not they contain foreign matter (Configuration Example 1). [Figure 9] FIG. 10 is an explanatory diagram of a transfer plate provided on the forward / reverse switching conveyor. [Figure 10] 1 is a table showing dimensions and weights of common bale products. [Figure 11] This is an example of a typical bale clamp (transporter). [Figure 12]This is a plan view showing the addition of a forward / reverse switching conveyor and a discharge conveyor that sorts bales based on whether or not they contain foreign objects (Configuration Example 2). [Figure 13] 13 is an explanatory diagram of the operation of the right-angle rotating conveyor of FIG. 12. DETAILED DESCRIPTION OF THE INVENTION

[0020] An X-ray inspection apparatus according to the present invention will now be described with reference to the drawings.

[0021] FIG. 1 is a plan view of an X-ray inspection apparatus 100 according to the present invention. The X-ray inspection apparatus 100 includes a box-shaped inspection box 1, with a conveyor 20 arranged so as to pass through the inspection box 1 continuously from left to right. An entrance shutter 6 is provided on the entrance side of the inspection box 1, and an exit shutter 7 is provided on the exit side. The conveyor 20 is made up of an inlet conveyor 2 on the entrance side of the inspection box 1, an inspection conveyor 3 inside the inspection box 1, and an outlet conveyor 4 on the exit side of the inspection box 1. The inspection conveyor 3 is made up of a first inspection conveyor 3A and a second inspection conveyor 3B. These conveyors are not physically connected, but are arranged so as to be continuous.

[0022] In this embodiment, the conveyor 20 is a roller conveyor. For example, the roller conveyor has a gear at one end of the roller and a motor driving the chain. The waste plastic 5, such as bales, is transported on the conveyor 20. Examples of bales include blocks made by compressing and packaging collected PET bottles. In this embodiment, the waste plastic is described as blocks such as bales. The speed of the conveyor 20 is, for example, approximately 12 m / min. For ease of explanation, the positions on the conveyor 20 are labeled A through E. For example, the time it takes for the waste plastic 5 to move through one block is approximately 8 seconds. The entrance shutter 6 and the exit shutter 7 each consist of two left and right doors, and the opening and closing time can be approximately 4 seconds. To transport the waste plastic 5 from A to B, the input conveyor 2 and the first inspection conveyor 3A are driven simultaneously. To transport the waste plastic 5 from B to C, the first inspection conveyor 3A and the second inspection conveyor 3B are driven simultaneously. To transport the waste plastic 5 from the point C to the point D, the second inspection conveyor 3B and the carry-out conveyor 4 are driven simultaneously.

[0023] FIG. 2 is a front view of an X-ray inspection apparatus 100 according to the present invention. The inspection box 1 includes an X-ray source 8 and a line sensor 9. The inspection conveyor 3 is composed of a first inspection conveyor 3A and a second inspection conveyor 3B. The X-ray passes between the two conveyors, the first inspection conveyor 3A and the second inspection conveyor 3B, and reaches the line sensor 9. This prevents the chain that rotates the roller conveyor from being captured by the line sensor 9. In this embodiment, the X-ray is irradiated from above the waste plastic 5, such as bales of waste plastic. When the waste plastic 5 moves from position B to position C, imaging of the waste plastic 5 is completed. As shown in FIG. 2, the carry-in conveyor 2 is positioned opposite the entrance shutter 6. When the entrance shutter 6 is closed, the carry-in conveyor 2 and the inspection conveyor 3A are separated. Similarly, when the exit shutter 7 is closed, the inspection conveyor 3B and the discharge conveyor 4 are separated. When the entrance shutter 6 and the exit shutter 7 are closed, the box-shaped inspection box 1 encloses the X-ray source 8, the line sensor 9, and the inspection conveyor 3, so that even if X-rays are irradiated, they do not leak outside the inspection box 1.

[0024] Figure 3 is a cross-sectional view taken along the line AA in Figure 2. The X-ray source 8 and line sensor 9 have a triangular X-ray irradiation range that covers the waste plastic 5. If the waste plastic 5 is a bale 5, for example, it is 1 m high, so the bale 5 is set to fit within the triangular X-ray irradiation range. The width of the irradiation range is set wider than the width of the inspection conveyor 3. The entrance shutter 6 consists of a rear door section 11 and a front door section 12, and when it is open, the bale 5 is sent into the inspection box 1 through the opening 10.

[0025] Figure 4 is a cross-sectional view taken along the line AA when X-rays are irradiated from below the rear. The inspection conveyor 3 is within the triangular irradiation range of the X-rays, but the inspection conveyor 3 is separated in the conveying direction and does not affect the imaging of the waste plastic 5. The X-ray source 8 and line sensor 9 may be arranged as shown in Figure 3 or as shown in Figure 4. These two X-ray arrangements may also be arranged serially. In this case, the shape of the foreign object can be clearly determined based on its position.

[0026] Figure 5 is a diagram of the shutter opening and closing structure. It can be applied to the entrance shutter 6 and the exit shutter 7. (A) shows the entrance shutter closed, and (B) shows the entrance shutter open. The rear door section 11 and the front door section 12 slide horizontally. The rear door section 11 and the front door section 12 slide by rotating screws with opposite screw orientations using a motor 16. When the entrance shutter is open, the opening 10 becomes visible. The motor 16 can be installed separately for the entrance shutter 6 and the exit shutter 7, or it can be installed in common.

[0027] Figure 6 is a control time chart of the X-ray inspection device 100 according to the present invention. The vertical stripes indicate that the conveyor is in operation. This indicates that the conveyor 20 is in operation and transporting waste plastics 5 (bales). The sections without vertical stripes indicate that the conveyor 20 is stopped. The vertical stripes last approximately 8 seconds, during which the waste plastics 5 can move, for example, from position A to position B. In the meshed sections indicating imaging, images of the first waste plastics 5 (first bale) and the second waste plastics 5 (second bale) are taken. Before imaging, the entrance shutter 6 and exit shutter 7 are closed, and after imaging, the entrance shutter 6 and exit shutter 7 are opened. Even if the waste plastics 5 are continuously fed, one imaging takes 24 seconds (= (8 seconds + 4 seconds) × 2). Since the entrance shutter 6 and exit shutter 7 are closed during X-ray imaging, leakage of X-rays from the inspection box 1 is prevented. As shown in FIG. 6, in this embodiment, the carry-in conveyor 2, the inspection conveyor 3, and the carry-out conveyor 4 are intermittently operated by repeating an 8-second drive and 4-second stop.

[0028] FIG. 7 is a control flowchart of the X-ray inspection device 100 according to the present invention. In step S1, waste plastic 5 (bale items) is transported to position A on the conveyor 20. Reference symbols A to D refer to FIG. 1. In step S2, the input conveyor 2 is driven, and simultaneously the inspection conveyor 3 is driven, to move the waste plastic 5 into the X-ray box 1 (A ⇒ B). In step S3, the entrance shutter 6 and the exit shutter 7 are closed. In step S4, the inspection conveyor 3 (3A, 3B) is driven, to move the waste plastic 5 from position B to position C, and simultaneously X-rays are irradiated to image the waste plastic. In step S5, the entrance shutter 6 and the exit shutter 7 are opened. In step S6, the inspection conveyor 3 is driven, and simultaneously the output conveyor 4 is driven, to push the waste plastic 5 from the X-ray box 1 to the output conveyor 4 (C ⇒ D). This movement shows the movement of the first waste plastic 5 in FIG. 5. As shown in the movement of the second waste plastic 5 in Figure 6, these processes proceed with some overlapping control. For example, in the section where the first waste plastic 5 moves from C to D, the second waste plastic 5 simultaneously moves from A to B, preparing for the next image capture.

[0029] Figure 8 is a plan view (Configuration Example 1) in which a forward / reverse switching conveyor and a discharge conveyor are added to sort waste plastics according to the presence or absence of foreign objects (lithium-ion batteries in this case). In Configuration Example 1, in addition to the configuration in Figure 1, an input conveyor 14 is placed upstream of the carry-in conveyor 2. Because the carry-in conveyor 2 operates intermittently, it is difficult to time the input of waste plastics 5 using the bale clamp 19, which is a transporting device. By providing a long input conveyor 14, multiple pieces of waste plastics 5 can be input at once if there is space.

[0030] As shown in Figure 8, in addition to the configuration shown in Figure 1, Configuration Example 1 also includes a forward / reverse switching conveyor 21 downstream of the discharge conveyor 4, and discharge conveyors 15 and 15' on one side and the other side of the forward / reverse switching conveyor 21. This allows waste plastic 5 containing lithium-ion batteries and waste plastic 5 without lithium-ion batteries to be transported in different directions. If flammable hazardous materials such as lithium-ion batteries are detected through X-ray imaging of the waste plastic 5, the rollers of the forward / reverse switching conveyor 21 are reversed, sending the waste plastic 5 backward. If no hazardous materials are found, the rollers of the forward / reverse switching conveyor 21 are rotated forward, sending the waste plastic 5 forward. The discharge conveyor 4 is arranged in a T-shape so that its conveying direction is perpendicular to the conveying directions of the forward / reverse switching conveyor 21 and the discharge conveyors 15 and 15'. The rollers of the discharge conveyor 4 push the waste plastic 5 onto the forward / reverse switching conveyor 21, and a pusher 13 is provided to increase the pushing force. In addition, a delivery plate 22 is provided on the forward / reverse switching conveyor 21 side to reduce friction of the waste plastic 5.

[0031] Figure 9 is an explanatory diagram of the transfer plate 22 provided on the forward / reverse switching conveyor 21. A plurality of small rollers 34 are provided on the upper part of the transfer plate 22, which reduces friction of the waste plastic 5. The transfer plate 22 is normally located at a lower position than the rollers 33 of the forward / reverse switching conveyor 21, and as shown in Figure 9(A), when the waste plastic 5 is pushed out from the discharge conveyor 4, it protrudes to a position higher than the rollers 33. As shown in Figure 9(B), when the forward / reverse switching conveyor 21 sends the waste plastic 5 to the discharge conveyors 15, 15', the transfer plate 22 moves downward, and the small rollers 34 descend to a position lower than the rollers 33.

[0032] Figure 10 is a table showing the dimensions and weight of typical bales of waste plastic. A bale made from compressed used PET bottles measures 60 x 40 x 60 cm in length x width x height and weighs 30-40 kg. A bale of compressed waste plastic measures 100 x 100 x 100 cm in length x width x height and weighs 180-200 kg. The outside is bound with bands. However, it may also be packed into flexible container bags (plastic bags).

[0033] Fig. 11 shows an example of a general bale clamp (conveyor). To feed bale items 5 as waste plastics onto the feeding conveyor 14, a bale clamp (conveyor) 19 is effective because of the weight of the bale items.

[0034] FIG. 12 is a plan view (Configuration Example 2) in which a forward / reverse switching conveyor 21 and discharge conveyors 15, 15' are added to sort baled products 5 as waste plastics based on the presence or absence of foreign objects (here, lithium-ion batteries). In Configuration Example 2, the discharge conveyor 4 is positioned so that its conveying direction is parallel to the conveying directions of the forward / reverse switching conveyor 21 and the discharge conveyors 15, 15'. A right-angle rotating conveyor 30 is installed between the discharge conveyor 4 and the forward / reverse switching conveyor. When baled products 5 are sent from the discharge conveyor 4 to the right-angle rotating conveyor 30, the right-angle rotating conveyor 30 rotates, causing a wall 31 to fall to the position indicated by the two-dot chain line. The wall 31 acts as a bridge, connecting to the connecting conveyor 32, allowing the baled products 5 to be sent to the forward / reverse switching conveyor 21.

[0035] FIG. 13 is an explanatory diagram of the right-angle rotating conveyor 30 of FIG. 12. As shown in FIG. 13(A), multiple rollers 33 are embedded in the wall 31 of the right-angle rotating conveyor 30. As shown in FIG. 13(B), when the right-angle rotating conveyor 30 rotates at a right angle, approximately 90 degrees, the wall 31 becomes the bottom and the bale 5 rests on the rollers 33 of the wall 31. As shown in FIG. 13(C), when the back of the bale 5 is pushed by the pusher 13, the bale 5 is sent to the connecting conveyor 32. The connecting conveyor 32 is installed at a slight incline, so the bale 5, which is waste plastic, slides down. As shown in FIG. 13(D), the transfer plate 22 is protruded and inclined so that it is higher than the rollers 33 of the forward / reverse switching conveyor 21, and the bale 5 arrives at the forward / reverse switching conveyor 21. Thereafter, the delivery plate 22 is lowered below the rollers 33 of the forward / reverse switching conveyor 21, and the bale 5 can be sent to the discharge conveyors 15, 15 by rotating the rollers 33 of the forward / reverse switching conveyor 21 forward or backward. Note that instead of using the pusher 13, a mechanism may be used in which the rollers 33 are rotated by a motor to push out the bale. [Industrial Applicability]

[0036] The present invention is suitable as an X-ray inspection device for baled products that can effectively prevent X-ray leakage. Waste plastics made up of baled products are crushed or pulverized into pellets, but if lithium-ion batteries are mixed in, there is a risk of them catching fire. The X-ray inspection device of the present invention can detect lithium ion batteries and is also effective as an X-ray inspection device for sorting plastic raw materials in baled goods, RPF, small household appliances, or general waste. [Explanation of symbols]

[0037] 1 Inspection Box 2. Intake conveyor 3 Inspection conveyor 4. Discharge conveyor 5. Waste plastic (baled) 6 Entrance shutter 7 Exit shutter 8 X-ray source 9 Line Sensor 10 Opening (entrance side) 11 Rear door section 12 Front door section 13 Pusher 14 Input conveyor 15, 15' discharge conveyor 16 motors 17 Screw 18 Opening 19 Bale clamp (transporter) 20 Conveyor 21 Forward / reverse switching conveyor 22 Delivery board 23 Stopper 30 Right-angle rotating conveyor 31 Wall 32 Connecting conveyor 33 Roller 34 Small roller 100 X-ray inspection equipment

Claims

1. An X-ray inspection device for sorting plastic raw materials in bales, RPF, small household appliances, or general waste, a conveyor for transporting waste plastic, the conveyor comprising an infeed conveyor, an inspection conveyor, and an outfeed conveyor; An inspection box that takes the waste plastic transported on the carry-in conveyor into the inspection conveyor from an entrance, irradiates it with X-rays to inspect for the presence or absence of lithium ion batteries, and discharges it from an exit to the carry-out conveyor; an entrance shutter provided in the inspection box, which closes the entrance by sliding during the X-ray irradiation and separates the carry-in conveyor from the inspection conveyor; an exit shutter that is provided in the inspection box and that closes the exit by sliding during the X-ray irradiation, and separates the inspection conveyor from the carry-out conveyor; A forward / reverse switching conveyor is disposed downstream of the carry-out conveyor, and discharge conveyors are provided on one side and the other side of the forward / reverse switching conveyor, so that waste plastics with lithium ion batteries and waste plastics without lithium ion batteries are transported in different directions; an X-ray inspection device characterized in that the discharge conveyor is arranged so that its conveying direction is parallel to the conveying directions of the forward / reverse switching conveyor and the discharge conveyor, and a right-angle rotating conveyor having rollers on its wall is provided between the discharge conveyor and the forward / reverse switching conveyor.

2. 2. The X-ray inspection apparatus according to claim 1, wherein the inspection conveyor comprises a first inspection conveyor and a second inspection conveyor, and the X-ray source and the line sensor are arranged so that X-rays pass between the first inspection conveyor and the second inspection conveyor.

3. 2. The X-ray inspection apparatus according to claim 1, wherein the waste plastic is a bale product obtained by compressing and solidifying waste plastic into a block body.

Images