Electrostatic separation device

Abstract

An electrostatic sorting device (500) charges mixed resin pieces (100) of a plurality of kinds, carries the charged resin pieces (100a, 100b) to an electrostatic field space, makes them fall while being displaced within the electrostatic field space, and sorts the resin pieces (100a, 100b), wherein an automatic charge amount measuring system (7) that measures the charge amount of the resin pieces (100a, 100b) is provided, and the automatic charge amount measuring system (7) picks up a part of the resin pieces (100a, 100b) at the time of the carrying, and measures the charge amount of the picked-up resin pieces (100a, 100b).

Description

Technical Field

[0001] This application relates to an electrostatic sorting device. Background Technology

[0002] When a mixture of fragments made of various materials is stirred or otherwise rubbed together, the materials become charged with a charge symbol and a charge corresponding to the type of material and the composition of the mixture. For example, this property can be used in the resin recycling process to drop charged mixed resin flakes into an electrostatic field space clamped by high-voltage electrodes, and use electrostatic force to displace them, thereby performing electrostatic sorting for each material.

[0003] For example, as shown in Patent Document 1, a method is proposed to form an electrostatic field space between a roller-type grounding electrode and a plate-shaped high-voltage electrode and to electrostatically sort mixed resin sheets.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2004-195303 (paragraphs 0014-0015) Figure 1 ) Summary of the Invention

[0007] However, in the method of Patent Document 1, there is a problem of foreign matter being mixed in due to poor charging of the resin sheet.

[0008] This application was made to solve the problems mentioned above, and its purpose is to provide an electrostatic sorting device that has the function of automatically and in real time measuring the charge of each resin sheet that has just been picked up and is now charged.

[0009] The electrostatic sorting device disclosed in this application is an electrostatic sorting device that sorts various resin sheets by charging them and causing the charged resin sheets to fall in an electrostatic field space. The electrostatic sorting device is characterized by having a charge measurement system for calculating the charge of the resin sheets. The charge measurement system picks up a portion of the charged resin sheets before sorting and calculates the charge of the picked-up resin sheets.

[0010] According to this application, when a charge trend different from the norm is detected, measures such as stopping the circuit can be taken to prevent foreign matter contamination caused by poor charge of the resin sheet and to optimize sorting conditions. Attached Figure Description

[0011] Figure 1 This is a structural diagram showing the electrostatic sorting device according to Embodiment 1.

[0012] Figure 2This is a structural diagram of the automatic charge measurement system in the electrostatic sorting device according to Embodiment 1.

[0013] Figure 3 This is a structural diagram showing in detail the input section of the electrostatic sorting device according to Embodiment 2.

[0014] Figure 4 This is a structural diagram showing the electrostatic sorting device according to Embodiment 3. Detailed Implementation

[0015] Implementation method 1.

[0016] Figure 1 This is a diagram illustrating the structure of the electrostatic sorting apparatus 500 according to Embodiment 1 of this application. Figure 1 As shown, the electrostatic sorting device 500 includes: a charged section 120 for stirring the sorting object 100, which is a sheet of mixed resin containing multiple materials, to make it triboelectrically charged; opposing electrodes 170, which are composed of a first opposing electrode 3 and a second opposing electrode 4 forming an electrostatic field space between opposing electrodes; a conveying section 130, which is a vibrating feeder for conveying the sorting object 100 charged by the charged section 120 to the electrostatic field space; and a recovery container 140, which is provided with a partition 150 for sorting and recovering the resin sheet that falls while displacing within the electrostatic field space.

[0017] The first phase electrode 3 is electrically grounded and is located at the lower part of the conveying section 130 and on the side of the energized section 120. The second phase electrode 4 is subjected to a high voltage through a high voltage power supply 110 and is located at the lower part of the conveying section 130. The two sides of the second phase electrode 4, which is subjected to a high voltage, are connected to insulators (not shown) and are structurally supported.

[0018] Near the conveying section 130, there is a resin sheet pickup section 1, which serves as a jet loader for sucking in resin sheets. Downwind of the resin sheet pickup section 1, there is an input section 6 that feeds resin sheets one by one. Below the input section 6, there is an automatic charge measurement system 7 that automatically measures the charge of the resin sheets as they pass through. Below the automatic charge measurement system 7, there is a resin sheet discharge section 20 that discharges the resin sheets after charge measurement upstream of the charged section or is a discarded resin sheet discharge section.

[0019] Figure 2 This is a detailed structural diagram illustrating the automatic charge measurement system 7 in the electrostatic sorting apparatus 500 according to Embodiment 1 of this application. Figure 2As shown, the automatic charge measurement system 7 includes a first conductive component 8, which is a metal tube, and a second conductive component 9, which is a metal tube larger than the first conductive component 8. The first conductive component 8 and the second conductive component 9 are joined by an insulating support member 13 with high insulation resistance, the insulating support member 13 being a bolt made of PTFE (polytetrafluoroethylene). The second conductive component 9 is connected to ground. The first conductive component 8 is connected via a shielded cable 12 to an electrostatic charge waveform measuring unit 10, which has external input / output terminals (not shown), and is a type of electrostatic meter. The shielded cable 12 is branched and connected to a current-eliminating unit 17, which is a relay connected to ground. Above the first conductive component 8 is an object detection unit 18, which is a light sensor that detects a resin sheet being inserted. Furthermore, the external input / output terminals of the electrostatic charge waveform measuring unit 10 and the external input / output terminals of the current-eliminating unit 17 are connected to a control unit 15, which is a sequence generator. Furthermore, the control unit 15 is connected to the arithmetic unit 16, which is a personal computer (PC), and the object detection unit 18.

[0020] Next, use Figure 1 as well as Figure 2 This document describes the operation of the electrostatic sorting apparatus 500 according to Embodiment 1 of this application. In this example, the sorting object 100 is described as being composed of a mixture of two resin materials. Additionally, an example is shown where a positive high voltage is output from the high-voltage power supply 110.

[0021] First, initially, the resin materials are rubbed together and charged by stirring within the charged section 120, so that one material becomes positively charged and the other becomes negatively charged.

[0022] Next, by applying a positive high voltage to the second opposing electrode 4 from the high voltage power supply 110, an electrostatic field space is formed between the opposing electrodes 170.

[0023] Next, the triboelectrically charged sorting objects 100 (resin sheets 100a and 100b) are transported by the conveying section 130, which is composed of a vibrating feeder, and placed into the opposing electrodes 170. At this time, the resin sheet 100a, which is positively charged due to electrostatic force, is attracted to the side of the first opposing electrode 3 (which is the negative electrode), and the resin sheet 100b, which is negatively charged, is attracted to the side of the first opposing electrode 4 (which is the positive electrode), thereby separating the resin sheets 100a and 100b.

[0024] The separated resin sheets are recycled in the recovery container 140 below the opposing electrode 170 according to the material.

[0025] On the other hand, it is used as part of the resin sheet pick-up unit 1 of the jet loader to suck up the mixed resin sheet after it has been triboelectrically charged.

[0026] Next, the mixed resin sheets sucked in and conveyed by the resin sheet pickup unit 1 are supplied to the input unit 6. The input unit 6 has a downward-narrowing structure and is equipped with an opening and closing device. Since the opening and closing device opens and closes at a certain time interval, the resin sheets are input one by one from the input unit 6 into the automatic charge measurement system 7 below.

[0027] Next, as the resin sheet that has fallen below is detected by the object detection unit 18, a signal from the control unit 15 is received, and the grounding inside the current-eliminating unit 17 is opened, thereby making the grounding of the first conductive member 8 open. Afterwards, the resin sheet falls near the first conductive member 8 and passes through. Furthermore, the first conductive member 8 is normally connected to the grounding via the current-eliminating unit 17.

[0028] At this time, the electrostatic charge waveform measurement unit 10 measures the charge waveform (current or voltage waveform) induced by electrostatics in the first conductive member 8 due to the charge of the resin sheet, and sends the charge waveform signal to the calculation unit 16 via the control unit 15.

[0029] Next, the calculation unit 16 calculates the amplitude value or time integral value of the charge waveform, and substitutes it into the linear relationship with the charge measurement results of commercially available Faraday cups and the like obtained through prior experiments, thereby converting it into charge.

[0030] After the resin sheet exits from the first conductive component 8, it receives a signal from the control unit 15, and the grounding inside the power disconnection unit 17 is turned on, thereby turning the grounding of the first conductive component 8 on.

[0031] In this way, the first conductive component 8 is always connected to the ground except during the period when the resin sheet is inserted, thereby preventing the reduction in measurement accuracy due to the charging of the first conductive component 8.

[0032] Then, the resin sheet exiting from the first conductive component 8 is drawn into the resin sheet discharge section 20 and supplied to the charged section 120 again.

[0033] By repeating the above actions, the charge of each picked-up resin sheet can be measured automatically and in real time, and the charge data of each resin sheet is accumulated in the calculation unit 16, which serves as a PC. In addition, if a charge trend different from the norm is detected, measures such as stopping the circuit can be taken to prevent foreign matter contamination caused by poor charge of the resin sheet and to optimize the sorting conditions.

[0034] As described above, according to the electrostatic sorting apparatus 500 of Embodiment 1, the electrostatic sorting apparatus 500 charges various resin sheets 100, and sorts the charged resin sheets 100a and 100b by causing them to fall in an electrostatic field space. It includes an automatic charge measurement system 7 for calculating the charge of the resin sheets 100a and 100b. Before the sorting, the automatic charge measurement system 7 picks up a portion of the resin sheets 100a and 100b and calculates the charge of the picked-up resin sheets 100a and 100b. Therefore, in the event of detecting a charge trend that is different from the usual one, it can be used to prevent foreign matter from being mixed in due to poor charging of the resin sheets and to optimize the sorting conditions by taking measures such as stopping the circuit.

[0035] In addition, the automatic charge measurement system 7 includes: an object detection unit 18 for detecting the picked-up resin sheets 100a and 100b; an electrostatic charge waveform measurement unit 10 for measuring the charge waveform induced by electrostatics due to the charge of the detected resin sheets 100a and 100b; and a calculation unit 16 for calculating the charge based on the charge waveform, so that the charge of each picked-up resin sheet can be measured automatically and in real time.

[0036] Furthermore, the automatic charge measurement system 7 includes a cylindrical first conductive member 8 into which resin sheets 100a and 100b are inserted. The electrostatic induction charge waveform measurement unit 10 measures the charge waveform of the resin sheets 100a and 100b inserted through the first conductive member 8. Moreover, the first conductive member 8 includes a ground-connected charge removal unit 17, which opens the ground circuit when the resin sheets 100a and 100b are detected by the object detection unit 18. Therefore, it is possible to prevent the reduction in measurement accuracy caused by the charging of the first conductive member.

[0037] Implementation method 2.

[0038] In Embodiment 1, the case of automatically feeding resin sheets one by one from the feeding section 6 downwards into the charge measurement system 7 is described, but in Embodiment 2, the case of feeding using a conveyor is described.

[0039] Figure 3 This is a structural diagram showing in detail the input section 6 of the electrostatic sorting apparatus 500 according to Embodiment 2 of this application. Figure 3 As shown, in Embodiment 2 of this application, the input section 6 is a conveyor, a plate-shaped first conductive member 8 is arranged above the input section 6, and a second conductive member 9 is arranged above the first conductive member 8 at a certain distance to cover the first conductive member 8.

[0040] Other structures of the electrostatic sorting device 500 in Embodiment 2 are the same as those in Embodiment 1, and their description is omitted.

[0041] Next, use Figure 3 This describes the operation of the electrostatic sorting device 500 according to Embodiment 2 of this application.

[0042] The resin sheet 100a (or 100b) sucked in and transported by the resin sheet pickup unit 1 is different from the embodiment 1 in which the resin sheet is fed into the input unit, which narrows downward, and is supplied to the input unit 6, which serves as a conveyor.

[0043] Next, the resin sheet 100a (or 100b) is conveyed along direction A by the rotation of the belt in the feeding section 6. When the amount of resin sheet fed is large and dense, air can be automatically blown onto the resin sheet to divide the quantity.

[0044] Next, as the resin sheet is detected by an object passing directly below the object detection unit 18, which acts as a light sensor, a signal is received from the control unit 15, and the grounding inside the current-eliminating unit 17 is opened, thus making the grounding of the first conductive member 8 open. Afterward, the resin sheet passes near the first conductive member 8 by being conveyed in a conveyor.

[0045] At this time, the electrostatic charge waveform measurement unit 10 measures the charge waveform (current or voltage) induced by electrostatics in the first conductive member 8 due to the charge on the resin sheet, and sends the charge waveform signal to the calculation unit 16 via the control unit 15.

[0046] Next, the calculation unit 16 calculates the amplitude value or time integral value of the charge waveform, and substitutes it into the linear relationship with the charge measurement results of commercially available Faraday cups and the like obtained through prior experiments, thereby converting it into charge.

[0047] After the resin sheet passes near the first conductive member 8, it receives a signal from the control unit 15 and the ground inside the power-off unit 17 is turned on, thereby turning on the ground of the first conductive member 8.

[0048] In this way, except during the period when the resin sheet passes near the first conductive component 8, the first conductive component 8 is always connected to the ground, thereby preventing the reduction in measurement accuracy caused by the charging of the first conductive component 8.

[0049] Then, the resin sheet near the first conductive component 8 is drawn into the resin sheet discharge section 20 and supplied to the charged section 120 again.

[0050] By repeating the above actions, the charge of each picked-up resin sheet can be automatically and in real time measured, and the charge data of each resin sheet is accumulated in the calculation unit 16, which serves as a PC. In addition, if a charge trend different from the norm is detected, measures such as stopping the circuit can be taken to prevent foreign matter contamination caused by poor charge of the resin sheet and to optimize the sorting conditions.

[0051] Other operations of the electrostatic sorting device 500 in Embodiment 2 are the same as those of the electrostatic sorting device 500 in Embodiment 1, and their description is omitted.

[0052] As described above, the electrostatic sorting apparatus 500 according to Embodiment 2 includes an input section 6 for inputting charged resin sheets 100a and 100b into an automatic charge measurement system 7. The input section 6 uses a conveyor, so the same effect as Embodiment 1 can be obtained.

[0053] Implementation method 3.

[0054] In Embodiment 3, the case where the partition 150 provided in the recycling container 140 is movable will be described.

[0055] Figure 4 This is a diagram illustrating the structure of the electrostatic sorting apparatus 500 according to Embodiment 3 of this application. Figure 4 As shown, in the electrostatic sorting apparatus 500 according to Embodiment 3 of this application, the partition 150 provided in the recycling container 140 is movable, and a sorting condition control unit 160 is provided that is connected to the automatic charge measurement system 7, the high voltage power supply 110 and the partition 150.

[0056] The partition 150 is configured to move in the B direction by being connected to an actuator (not shown), and the output voltage of the high-voltage power supply 110 and the movement of the partition 150 can be controlled by the sorting condition control unit 160.

[0057] The other structures of the electrostatic sorting device 500 in Embodiment 3 are the same as those in Embodiment 1, and their description is omitted.

[0058] Next, use Figure 4 This describes the operation of the electrostatic sorting device 500 according to Embodiment 3 of this application.

[0059] The arithmetic unit 16 within the automatic charge measurement system 7 analyzes the charge data of the mixed resin sheet measured by the automatic charge measurement system 7, determines the sorting conditions based on the charge trend, and sends a signal to the sorting condition control unit 160.

[0060] The sorting condition control unit 160 controls the high-voltage power supply 110 or the partition 150 according to the received signal, thereby performing sorting under the optimal conditions corresponding to the trend of the charge on the resin sheet.

[0061] For example, when the tendency for the integral resin sheet to become positively charged is strong, the position of the separator is moved towards the first phase electrode 3 (relatively negative). Conversely, when the tendency for the integral resin sheet to become negatively charged is strong, the position of the separator is moved towards the second phase electrode 4 (relatively positive). When the charge on the integral resin sheet is higher than usual, the output voltage of the high-voltage power supply 110 is reduced; conversely, when the charge on the integral resin sheet is lower than usual, the output voltage of the high-voltage power supply 110 is increased.

[0062] In this way, when a different charge trend is detected due to changes in the material of the resin sheet, stable sorting performance can be achieved by optimizing the sorting conditions of the electrostatic sorting device.

[0063] Other operations of the electrostatic sorting device 500 in Embodiment 3 are the same as those of the electrostatic sorting device 500 in Embodiment 1, and their description is omitted.

[0064] As described above, in the electrostatic sorting apparatus 500 according to Embodiment 3, the partition 150 is equipped with a movably disposed recycling container 140. The partition 150 is moved according to the charge of the resin sheets 100a and 100b. Therefore, when a charge trend different from the usual is detected due to changes in the material of the resin sheets, stable sorting performance can be achieved by optimizing the sorting conditions of the electrostatic sorting apparatus.

[0065] This application describes various exemplary embodiments and examples, but the various features, methods, and functions described in one or more embodiments are not limited to the application of a specific embodiment and can be applied to the embodiments individually or in various combinations. Therefore, within the scope of the technology disclosed in this application, numerous variations not illustrated are contemplated. For example, these include cases where at least one constituent element is modified, at least one constituent element is added, at least one constituent element is omitted, or at least one constituent element is extracted and combined with constituent elements of other embodiments.

[0066] (Symbol Explanation)

[0067] 6: Input section; 7: Automatic charge measurement system; 8: First conductive component; 9: Second conductive component; 10: Electrostatic induction charge waveform measurement section; 16: Calculation section; 17: Charge removal section; 18: Object detection section; 100: Sorting object; 100a, 100b: Resin sheet; 120: Charged section; 500: Electrostatic sorting device.

Claims

1. An electrostatic sorting device that charges a plurality of resin pieces, and sorts the charged resin pieces by dropping them in an electrostatic field space, characterized by comprising: a charge amount measuring system that measures a charge amount of the resin pieces, wherein the charge amount measuring system picks up a part of the charged resin pieces before the sorting, measures a charge amount of the picked-up resin pieces, detects a case where a tendency of the measured charge amount is different from a general charge amount tendency, and when the case where the tendency of the measured charge amount is different from the general charge amount tendency is detected, determines a sorting condition based on the tendency of the charge amount of the resin pieces to perform the sorting in an optimum sorting condition corresponding to the tendency of the charge amount of the resin pieces.

2. The electrostatic sorting device according to claim 1, characterized in that the charge amount measuring system comprises: a detection unit that detects the picked-up resin pieces; a measurement unit that measures a charge waveform electrostatically induced by the charge of the detected resin pieces; and a calculation unit that calculates a charge amount based on the charge waveform.

3. The electrostatic sorting device according to claim 2, characterized in that the charge amount measuring system comprises a cylindrical conductive member into which the resin pieces are thrown, and the measurement unit measures a charge waveform of the resin pieces thrown into the conductive member.

4. The electrostatic sorting device according to claim 3, characterized in that the conductive member comprises a grounding-connected charge removing unit, and the ground is opened at the same time as the resin pieces are detected by the detection unit.

5. The electrostatic sorting device according to any one of claims 2 to 4, characterized in that the electrostatic sorting device comprises a throwing unit that throws the charged resin pieces into the charge amount measuring system, and the throwing unit is in a shape that narrows toward a lower part of a vertical direction.

6. The electrostatic sorting device according to claim 2, characterized in that the electrostatic sorting device comprises a conveyor that throws the charged resin pieces into the charge amount measuring system.

7. The electrostatic sorting device according to any one of claims 1 to 4, 6, characterized in that the electrostatic sorting device comprises a recovery container in which a partition is movably provided, and the partition is moved based on the charge amount of the resin pieces.

8. The electrostatic sorting device according to claim 5, characterized in that the electrostatic sorting device comprises a recovery container in which a partition is movably provided, and the partition is moved based on the charge amount of the resin pieces. ​ ​ ​ ​ ​ ​ ​ ​ ​

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