JP2010099618A - Sorting method and sorting apparatus of plastic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sorting apparatus of plastic by selectively charging only plastic pieces to be sorted among plastic pieces for precisely attracting and recovering the plastic pieces. <P>SOLUTION: The sorting apparatus of plastic includes: a measuring means measuring the features and position of plastic pieces moving on a belt conveyer; an arithmetic operation means selecting the plastic pieces to be sorted by calculating the measured features and position of the plastic pieces; a charging means selectively charging only the plastic pieces to be sorted; and a recovery means recovering the charged plastic pieces by attracting by electrostatic power. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plastic separation method and a separation apparatus, and more particularly to a separation method and a separation apparatus in which only plastic pieces that are desired to be collected are selectively electrified by electrostatic charging and collected.

  For example, as shown in FIG. 7, a conventional electrostatic separation method for various plastic pieces uses a flat plate electrode 19 that is vertically installed to which a plastic high voltage is applied by charging the plastic piece positively or negatively by friction or the like. Drop it into the generated electric field. The charged plastic piece is attracted to the positive or negative electrode side by the electrostatic force during dropping, and the trajectory changes. According to the change in the trajectory, there has been known a separation method in which plastic pieces are collected by being divided into an ABS collection container 201, a re-sorting intermediate collection container 202, and a PS collection container 203 of the collection container 20 (see Patent Document 1). In addition, the plastic piece in FIG. 7 shows the sample of the plastic piece shown in FIG.

In addition, a separation method using a charging sequence of various kinds of plastic mixtures is known (see Patent Document 2). This is a plastic mixture charged so as to have a charging sequence by friction, in order from the end position on the plus or minus side of the charging sequence, through a plurality of stirring bars and stirring containers made of the same material, This is a separation method for electrostatic separation.
JP-A-7-178351 JP 2002-136894 A

  However, the conventional electrostatic separation is based on the classification corresponding to the charging order, but there is a problem that the position of the charging order changes greatly depending on the roughness of the plastic surface and the hygroscopicity. Therefore, in the case of electrification by simple friction, it is unstable because it is unknown whether the charge is positive or negative. In addition, the electrification due to friction has unevenness in the charge amount itself, which causes a reduction in the accuracy of sorting.

Furthermore, there is another problem that different plastics and plastic pieces having the same charging order cannot be classified according to color, shape, and size.
The present invention has been made in view of the background art as described above, and a plastic separation method and a separation apparatus that can selectively charge only a plastic piece that is desired to be separated from the plastic pieces, and can be adsorbed and recovered with high accuracy. The purpose is to provide.

  A plastic separating apparatus that solves the above problems includes a measuring means for measuring the characteristics and position of a plastic piece that moves on a belt conveyor, and a plastic piece that is calculated and sorted from the measured characteristics and position of the plastic piece. A charging means for selectively charging only the plastic pieces to be sorted, and a collecting means for attracting and collecting the charged plastic pieces by electrostatic force.

  A plastic separation method that solves the above problems includes a measuring step of measuring the characteristics and position of a plastic piece that moves on a belt conveyor, and a plastic piece that is calculated and sorted from the measured characteristics and position of the plastic piece. And a charging step of selectively charging only the plastic pieces to be sorted, and a recovery step of attracting and collecting the charged plastic pieces by electrostatic force.

The present invention can provide a plastic separation method and a separation apparatus that can selectively charge only a plastic piece that is desired to be separated from the plastic pieces, and can accurately adsorb and recover the plastic piece.
In addition, the present invention can selectively charge only the plastic to be collected, and does not depend on the charging sequence or the charge amount, and furthermore, the plastic piece can be accurately and individually classified according to the characteristics such as the type, color, shape and size of the plastic. It can be recovered.

Hereinafter, the present invention will be described in detail.
The plastic sorting apparatus according to the present invention selects a measuring means for measuring the characteristics and position of a plastic piece moving on a belt conveyor, and a plastic piece to be sorted by calculation from the measured characteristics and position of the plastic piece. And a charging means for selectively charging only the plastic pieces to be sorted, and a collecting means for attracting and collecting the charged plastic pieces by electrostatic force.

It is preferable that at least one measuring unit, one charging unit, and one collecting unit are provided in the traveling direction of the belt conveyor.
It is preferable that at least one charging unit is provided in the width direction of the belt conveyor.

It is preferable that the charging unit and the recovery unit are provided to face each other.
The plastic separation method according to the present invention includes a measuring step of measuring the characteristics and position of a plastic piece moving on a belt conveyor, and selecting a plastic piece to be sorted by calculation from the measured characteristics and position of the plastic piece. And a charging step of selectively charging only the plastic pieces to be sorted, and a recovery step of attracting and collecting the charged plastic pieces by electrostatic force.

Next, the plastic sorting apparatus and sorting method according to the present invention will be described together.
The measuring means in the present invention measures the characteristics and position of the plastic piece moving on the belt conveyor. Using the measuring means, a measuring step is performed for measuring the characteristics and position of the plastic piece moving on the belt conveyor.

  As the measuring means, a plastic identification sensor is used, for example, a line scan sensor or an area scan sensor. The identification sensor preferably has a smaller resolution in the width direction of the belt conveyor than the plastic piece. This makes it possible to identify the exact characteristics and position of the plastic piece.

  The characteristic of the plastic piece measured by the measuring means is preferably at least one selected from the type, color, shape and size of the plastic piece. The kind of plastic piece represents the material, the compounding ratio of additives, and the degree of deterioration due to heat, light, and humidity.

  The calculating means in the present invention selects a plastic piece to be sorted by calculating from the characteristics and position of the plastic piece measured by the measuring means. A calculating step of selecting a plastic piece to be sorted by calculation from the characteristics and position of the measured plastic piece is performed using the calculating means.

As the calculation means, a CPU (Central Processing Unit) and a storage device are used.
The charging means in the present invention selectively charges only the plastic pieces to be sorted selected by calculation by the calculation means. Using the charging means, a charging step of selectively charging only the plastic pieces to be sorted is performed. As a charging means for charging a plastic piece, a device that charges corona ions generated by applying high voltage to a needle electrode from a high voltage generation circuit typified by Cockcroft Walton or the like, or a belt conveyor A device that macroscopically charges a plastic piece by dielectrically polarizing a plastic piece by applying an electric field from above and below, or a device that induces and charges static electricity generated by the friction of a rubber belt typified by the Ben de Graf method. Etc. are used.

  The positive / negative of the charge for charging the plastic piece is preferably negative in view of the characteristics of the plastic. However, the charging means can charge the plastic piece unilaterally because it can be charged unilaterally.

  Furthermore, as charging means for selectively charging, a plurality of charging means are provided in the width direction of the belt conveyor, and charging can be performed only when a plastic piece to be separated passes, and the charging means is adjusted to the smallest size of the plastic piece. It is preferable to provide a plurality of locations.

  Since the plastic piece can be charged negatively or positively by the charging means, even if the position of the charging sequence changes greatly, the instability that does not know whether the plastic piece is charged negatively or positively is large. It is reduced. Further, even if there is unevenness in the charge amount, it can be selectively charged, so that the separation accuracy is improved.

  In the measuring means, one or more plastic identification sensors, that is, a camera such as a near-infrared ray or visible light CCD, can measure the characteristics such as the type, color, shape, size, etc. of the plastic piece. Can be charged and separated. Therefore, it is possible to easily classify different types of plastics and plastic pieces having the same charging sequence according to the type, color, shape and size.

  It is preferable to have one line or more of charging means for charging the plastic piece. As the charging means having one line or more, it is preferable to use the position of the plastic piece on the held belt conveyor and charge only when the plastic piece passes through the charging means. If the charging time of the plastic piece does not follow the conveying speed of the belt conveyor, other plastic pieces are charged, which is not preferable.

In the present invention, by having one or more charging means for charging the plastic piece, the charge amount of the plastic is increased and the separation accuracy is improved.
The collection means in the present invention collects the plastic pieces charged by the charging means by adsorbing them with electrostatic force. Using the recovery means, a recovery process is performed in which the charged plastic piece is adsorbed and recovered by electrostatic force. It is preferable to have a pair of charging means for charging the plastic piece and a collecting means for attracting and collecting the plastic piece by electrostatic force. For example, a charging drum is used as the collecting means.

  By having at least one pair of charging means for charging plastic pieces and charging drums that are attracted and collected by electrostatic force, it is possible to collect types, colors, shapes, and sizes according to the position and characteristics of the plastic pieces in multiple stages. It becomes easy.

Embodiments of the present invention will be described below with reference to the drawings.
Example 1
FIG. 1 is a block diagram showing an embodiment of a plastic sorting apparatus according to the present invention.

  In FIG. 1, the plastic sorting apparatus of the present invention includes a measuring means comprising a plastic identification sensor 4 for measuring the characteristics and position of the crushed plastic piece 1 flowing on the belt conveyor 13, and the measured characteristics and position of the crushed plastic piece 1. An arithmetic unit (CPU: central processing unit) 5 for selecting a plastic piece to be sorted by calculation from the above, and a charging unit comprising a charging device 7 for selectively charging only the plastic piece to be sorted The charging unit 10 includes a collecting means including a collecting charging drum 10 that adsorbs and collects the charged crushed plastic piece 1 by electrostatic force, and collecting containers 121 and 124 that collect the separated crushed plastic piece 1.

  The plastic identification sensor 4 measures characteristics such as the type, color, shape and size of the crushed plastic piece 1. Therefore, the feeder 2 for conveying the crushed plastic piece 1 without overlapping with the belt conveyor 13 and the light source 3 for improving and stabilizing the sensitivity of measurement are provided.

  In addition, the arithmetic unit 5 includes an encoder 14 for integrating the elapsed time or moving distance until the measured crushed plastic piece 1 reaches just below the charging device 7. Further, the charging device 7 is equipped with a static eliminating device 6 for neutralizing static electricity of all the crushed plastic pieces once in the previous process in order to selectively charge only the crushed plastic pieces to be collected with high accuracy. The charging drum 10 for collection includes a high voltage power supply 8 and a drum charging electrode 9 to be charged in order to charge the drum surface, and a scraper 11 that scrapes off a crushed plastic piece adsorbed on the drum.

  FIG. 3 is a schematic enlarged view of the charging device 7 in detail. The charging device 7 is a device for generating an electric field in a space through which the crushed plastic piece 1 passes, that is, perpendicular to the traveling direction of the belt conveyor. The charging device 7 includes a high voltage current voltage generation circuit 151, a relay control device 16 that applies the high voltage generated from the high voltage current voltage generation circuit 151 in synchronization with the position and arrival time of the crushed plastic piece determined by the arithmetic device 5, It consists of parallel plate electrodes 171 and 172 for dielectric polarization that generate an electric field from an applied high voltage.

  The embodiment will be described in more detail using the crushed plastic piece 1 as a sample shown in FIG. The sample shown in FIG. 8 is a crushed plastic piece, and is composed of a total of four types of two materials of black and white, each made of two materials of ABS (acrylonitrile / butadiene / styrene resin) and PS (polystyrene).

  The four types of crushed plastic pieces 1 are supplied to the belt conveyor 13 without being folded by a feeder 2 in which an oscillation mechanism is attached to a trough. The supplied crushed plastic piece 1 is measured by the CCD line scan camera of the identification sensor 4 with a resolution smaller than the size of the crushed plastic piece in both the traveling direction and the belt width direction. Here, in the pre-process of the CCD line scan camera, a white fluorescent light source 3 is installed in order to suppress irregular reflection as much as possible, to keep the light quantity constant and to stabilize the measurement.

  The measured color information is sequentially held in the arithmetic unit 5 together with the coordinate in the width direction of the belt conveyor 13 and the measurement time in order to specify the position. The moving distance in the traveling direction can be obtained by integrating the multiplication of the conveyance speed acquired from the encoder 14 installed on the rotating shaft of the belt conveyor 13 and the elapsed time.

  When the moving distance of the black crushed plastic piece reaches the charging device 7, the relay control device 16 shown in FIG. 3 acquires the position information in the width direction held by the arithmetic unit 5, and the black crushed plastic piece is dielectrically polarized. A positive or negative high voltage is applied only when it passes immediately above the parallel plate electrode 171 for use. An electric field is generated between the parallel plates for dielectric polarization 171 and 172 to which a high voltage is applied. The surface of the black crushed plastic piece that has passed therethrough is charged to the opposite polarity to the charge applied by the parallel plate electrode 171 for dielectric polarization by dielectric polarization in the plastic. In addition, in order to charge only the black crushing plastic piece efficiently and accurately, the static electricity of all the crushing plastic pieces 1 is always neutralized with the static elimination apparatus 6 of the previous process.

  Next, a voltage opposite to that of the high-voltage current-voltage generating circuit 151 is constantly applied to the drum charging electrode 9 by the drum charging high-voltage power supply 8. An electric field is generated between the drum charging electrode 9 and the recovery charging drum 10, and the surface of the recovery charging drum 10 is charged to the opposite polarity to the surface of the black crushed plastic piece. The black crushed plastic piece charged positively or negatively is adsorbed to the charging drum 10 by electrostatic force, scraped off by the scraper 11, and collected in the collecting container 121. The white crushed plastic pieces are transported as they are and collected in the collection container 124.

  The charging device 7 shown in the first embodiment may be selectively charged by spraying the corona ions generated from the corona discharge generator 173 shown in FIG. Further, a method may be used in which static electricity generated by friction of the rubber belt 1522 typified by the Ben de Graaf method shown in FIG.

  With the above configuration, the crushed plastic can be selectively separated even if the charging order is affected by the surface roughness and absorbability of the crushed plastic piece. Even if the charge amount itself is uneven, it can be accurately sorted.

  The plastic identification sensor 4 shown in the first embodiment is not necessarily a CCD line scan camera. That is, the sensor is not limited to CCD line scanning as long as it is a sensor that captures specific characteristics of plastic, such as an infrared camera, an X-ray camera, and an ultraviolet camera. Therefore, the object can be classified not only by the color but also by the difference in shape, size, material, additive and the like. Further, if it can be charged, the object to be separated need not be a crushed plastic piece. For example, it is not limited to this as long as it can be charged such as rubber, paper, glass fiber, and a piece of wood.

Example 2
FIG. 2 is a block diagram showing another embodiment of the plastic sorting apparatus of the present invention.
FIG. 2 shows a configuration in which two plastic identification sensors 4 and three charging devices 7 and three charging drums 10 are used in place of the plastic separating device by static electricity in the first embodiment.

  By mounting the plastic identification sensor 4 with a CCD line scan camera and a near infrared line scan camera, it is possible to identify not only the color of the crushed plastic piece but also the type. Therefore, by maintaining the integral of the multiplication of the identification result, the conveyance speed and the elapsed time, the two materials of ABS (acrylonitrile, butadiene, styrene resin) and PS (polystyrene) shown in FIG. A total of four types can be sorted sequentially in one process.

Example 3
FIG. 6 shows a configuration in which corona discharge generators 173 of the charging device 7 are arranged in a plurality of rows instead of the plastic sorting device by static electricity in the first embodiment of the present invention. Since the result of integrating the multiplication of the conveyance speed acquired from the encoder 14 installed on the rotating shaft of the belt conveyor 13 and the elapsed time is held, the crushed plastic piece is charged while following the conveyance speed of the belt conveyor. I can do things. That is, extra charging time can be secured. As a result, the conveying speed of the belt conveyor can be improved, and as a result, the collection amount can be increased.

  Since the plastic separation method and the separation apparatus of the present invention can selectively charge and recover only the plastic piece to be separated from the plastic pieces with high accuracy, it can be used as high-purity plastic recycling. .

It is a block diagram which shows one embodiment of the plastic separation apparatus of this invention. It is a block diagram which shows the other embodiment of the plastic separation apparatus of this invention. FIG. 3 is an enlarged explanatory view of a charging device in the present invention. It is an expansion explanatory view of modification 1 of the charging device in the present invention. FIG. 10 is an enlarged explanatory view of a second modification of the charging device according to the present invention. FIG. 10 is an enlarged explanatory view of a third modification of the charging device according to the present invention. It is a principle figure explaining the electrostatic separation of a prior art. It is explanatory drawing of a crushing plastic piece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crushing plastic piece 2 Feeder 3, 31, 32 Light source 4 Plastic identification sensor 41 CCD line scan camera 42 Near infrared line scan camera 5 Arithmetic device 6, 61, 62, 63 Static elimination device 7, 71, 72, 73 Charging device 8 81, 82, 83 High voltage power supply for drum charging 9, 91, 92, 93 Drum charging electrode 10, 101, 102, 103 Charging drum for recovery 11, 111, 112, 113 Scraper 121, 122, 123, 124 Recovery container DESCRIPTION OF SYMBOLS 13 Belt conveyor 14 Encoder 151 High voltage DC voltage generation circuit 1521 Electrostatic current collection part 1522 Electrostatic generation rubber belt 1523 Neutralization electrode 1524 Current collection electrode 16 Relay controller 171, 172 Parallel plate electrode for dielectric polarization 173 Corona discharge generation part 174 Static electricity Guide part 18 Hopper 19 Parallel plate electrode for dielectric polarization 20 Recovery container 201 ABS recovery container 202 Intermediate recovery container for re-sorting 203 PS recovery container

Claims (7)

  Measuring means for measuring the characteristics and position of a plastic piece moving on a belt conveyor, calculating means for selecting a plastic piece to be sorted by calculation from the measured characteristics and position of the plastic piece, and the plastic to be sorted A plastic separating apparatus comprising: charging means for selectively charging only a piece; and collection means for collecting and collecting the charged plastic piece by electrostatic force.   2. The plastic sorting apparatus according to claim 1, wherein the plastic piece has at least one characteristic selected from the type, color, shape, and size of the plastic piece.   4. The plastic separating apparatus according to claim 2, wherein at least one of the measuring unit, the charging unit, and the collecting unit is provided in the traveling direction of the belt conveyor.   4. The plastic sorting apparatus according to claim 1, wherein at least one charging unit is provided in a width direction of the belt conveyor.   5. The plastic sorting apparatus according to claim 1, wherein the charging unit and the collecting unit are provided to face each other.   A measuring step for measuring the characteristics and position of a plastic piece moving on a belt conveyor, a calculating step for selecting a plastic piece to be sorted by calculation from the measured characteristics and position of the plastic piece, and the plastic to be sorted A plastic separation method comprising a charging step of selectively charging only a piece and a recovery step of adsorbing and collecting the charged plastic piece by electrostatic force.   7. The plastic separation method according to claim 6, wherein the characteristic of the plastic piece is at least one selected from the kind, color, shape and size of the plastic piece.

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