JP3681311B2 - Plastic sorting method and plastic sorting apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plastic sorting apparatus and a plastic sorting method for sorting plastic pieces associated with recycling for each type.
[0002]
[Prior art]
In recent years, as the recycling of garbage is being promoted rapidly, as a technology for selecting a plurality of types of crushed plastic pieces by electrifying the polarity and charge amount of each plastic piece 1, that is, by charging a triboelectric charge train, there are plastic sorting device as shown in 9.
[0003]
This plastic sorting device is disposed below the friction charging device 3 for charging the plastic piece 1 to the polarity and charge amount of each type, and is separated according to the polarity and charge amount of the plastic piece 1. And an electrostatic separation device G.
[0004]
The electrostatic separation device G includes a metal drum electrode 5 disposed below the friction charging device 3 and configured to be rotatable in a predetermined direction, and a high voltage electrode 6 disposed obliquely above the metal drum electrode 5. I have. The high voltage electrode 6 is connected to, for example, a cathode of a high voltage power supply device 7.
[0005]
In the sorting method in the plastic sorting apparatus, first, a plurality of types of plastic pieces 1 are put into the frictional charging device 3 from the hopper 2 and stirred. Then, each plastic piece 1 is frictionally charged to the polarity / charge amount of each plastic piece 1 in accordance with the charging train. Thereafter, the plastic piece 1 is dropped on the electrostatic separation device G and passed through the electrostatic field for selection between the metal drum electrode 5 and the high voltage electrode 6, so that the positively charged plastic piece 1 is on the high voltage electrode 6 side. The plastic piece 1 that is negatively charged is drawn to the metal drum electrode 5 and collected to the container 9 side, or is scraped off and collected by the brush 9 with the brush 10.
[0006]
[Problems to be solved by the invention]
By the way, in the plastic sorting apparatus and the plastic sorting method, when the humidity of the separation atmosphere is high, it becomes difficult to charge the plastic piece, and the charge potential holding time is shortened. The humidity of the separation atmosphere this reason is high, polarity and charge amount of the plastic pieces 1 becomes unstable, the separation performance of the plastic pieces 1 that pass through the sorting electrostatic field is decreased as compared with the case of low humidity, Accordingly, the position where the plastic piece 1 is dropped becomes unstable, and the plastic piece 1 cannot be accurately electrostatically separated by type.
[0007]
Therefore, an object of the present invention is to provide a plastic sorting method and a plastic sorting apparatus that can solve the above-described problems.
[0008]
[Means for Solving the Problems]
The problem-solving means in the present invention is provided with a friction charging portion for stirring and triboelectrically charging different types of crushed plastic pieces, and the frictionally charged plastic piece has its polarity below the friction charging portion. A sorting section for sorting by charge amount is provided, and the sorting section is a rotary drum for electrostatically sucking a plastic piece of the same kind as this plastic piece in a predetermined plastic piece and a frictional charge train ; Further, a sorting electrode for forming a sorting electrostatic field is provided facing the peripheral surface of the rotary drum, and a heat source for heating the rotary drum or the sorting electrode is provided.
[0009]
The heat source is rotary arranged on the inner surface of the drum, or is provided et al is the screening electrode side.
In the above configuration, different types of crushed plastic pieces are agitated in the triboelectric charging unit to charge the plastic pieces for each polarity and charge amount, and the triboelectrically charged plastic pieces are separated for each polarity and charge amount in the sorting unit. when screened, by heating the rotary drum or sorting electrodes, improving the separation performance.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Note that the gist of the present invention was made by paying attention to the fact that the separation accuracy is affected by the humidity of the separation atmosphere when the crushed plastic piece is separated, so that it is not affected by this. In order to achieve this, the entire sorting atmosphere, which is the entire apparatus for performing electrostatic separation, is heated, or the rotary drum or the sorting electrode for forming an electrostatic field for sorting plastic pieces is heated. Can be considered.
[0011]
By the way, although only a heating part is different from the configuration of the present invention, when explaining the entire configuration of the plastic sorting apparatus according to the present embodiment, when the entire sorting atmosphere is easily heated (hereinafter, basic mode) In the following, the case of heating the rotary drum and the case of heating the sorting electrode, which are the gist of the present invention, will be described.
[0012]
As described above, first, the plastic sorting apparatus according to the basic embodiment will be described with reference to FIG.
This plastic sorting apparatus sorts a plurality of types of crushed plastic pieces 1 ( here, two types) as polarities / charge amounts for each plastic piece 1 in accordance with a frictional charge train.
[0013]
That is, this plastic sorting device supplies a friction charging device (friction charging unit) 3 having a stirring blade ( not shown) for charging the plastic piece 1 to a polarity and a charge amount for each type, and a lower portion of the friction charging device 3. It has an electrostatic separation device (electrostatic separation unit or sorting unit ) G that is arranged via the tray 2 and separates the plastic piece 1 according to its polarity and charge amount.
[0014]
The electrostatic separation device G includes a metal drum electrode (rotary drum) 5 disposed below the friction charging device 3 and configured to be rotatable in a predetermined direction (clockwise in the figure), and an oblique angle of the metal drum electrode 5. And a high voltage electrode (selection electrode) 6 disposed above. The high voltage electrode 6 is connected to, for example, a cathode of a high voltage power supply device 7, whereby the surface of the metal drum electrode 5 is an anode.
[0015]
Further, the electrostatic separation device G is disposed below the metal drum electrode 5 and is provided with a first container 8 and a second container 9 for collecting the plastic pieces 1 for each type.
[0016]
By the way, the plastic sorting apparatus in this basic form is provided with a heating means 15 for heating the sorting atmosphere, and the heating means 15 includes the supply tray 2, the metal drum electrode 5, the high voltage electrode 6 and the first voltage. A box 16 surrounding the container 8 and the second container 9 and a heat source 17 for heating the inside of the box 16, that is, the sorting atmosphere, are used as the heat source. A lamp or an infrared heater is used.
[0017]
The plastic sorting method in the plastic sorting apparatus is a method of separating and collecting PE from a plurality of types of plastic pieces 1, that is, a plastic piece 1 in which polyethylene (hereinafter referred to as “PE”) and polypropylene (hereinafter referred to as “PP”) are mixed. is there.
[0018]
First, the plastic pieces 1 of PE and PP are put into the friction charging device 3 and stirred. Then, PE and PP are triboelectrically charged to (+) and (−), respectively, according to the charge train. Thereafter, the frictional charging device 3 is opened, and the plastic piece 1 is dropped onto the supply tray 2 and dropped onto the electrostatic separation device G. On the other hand, when the humidity of the atmosphere is high, the heat source 17 is energized to raise the temperature in the box 16.
[0019]
The frictionally charged PE (+) and PP (−) are dropped and supplied from the supply tray 2 onto the surface of the metal drum electrode 5, and the cathode of the high voltage power supply device 7 is connected to the high voltage electrode 6. Since the surface of the electrode 5 is an anode, PE (+) repels the surface of the metal drum electrode 5 and is electrically drawn by the high voltage electrode 6 and falls into the first container 8 and is collected. The Conversely, PP (−) repels the high voltage electrode 6 and is adsorbed on the surface of the metal drum electrode 5, and falls to the second container 9 while moving to the second container 9 side by the rotation of the metal drum electrode 5. Alternatively, PP (−) electrically adsorbed on the metal drum electrode 5 is scraped off by the brush 10 into the second container 9 and collected.
[0020]
By the way, FIG. 8 is a graph showing the relative humidity (%) on the horizontal axis and the purity and recovery rate (%) of the plastic piece 1 on the vertical axis, and ● represents the case where the temperature in the box 16 was not adjusted. ○ indicates a case where the temperature is adjusted. From this graph, it can be seen that when the temperature is not adjusted, the purity / recovery rate decreases as the humidity increases. However, when the temperature is adjusted, that is, when the heat source 17 is energized, It can be seen that the purity / recovery increases when the temperature is raised.
[0021]
Specifically, as a result of an experiment under the same conditions of room temperature: 24 ° C. and humidity: 70% in the room where the plastic sorting apparatus is arranged, the recovery purity of PE is 60 to 70 in the conventional plastic sorting apparatus that does not use the heat source 17. When the temperature in the box 16 is increased using the heat source 17, the recovery purity of PE is 97 to 99% (equivalent to the conventional humidity of 55% even in a high humidity of about 70%). PE could be recovered with a purity of
[0022]
Thus, according to this basic form , the box 16 surrounding the supply tray 2, the metal drum electrode 5, the high voltage electrode 6 and the first container 8, the second container 9, and the box 16, By providing a heating means 15 composed of a heat source 17 for heating the sorting atmosphere, and energizing the heat source 17 to increase the temperature in the box 16 (drying the plastic piece 1), in high humidity Even so, PE and PP can be separated with high purity and recovery.
[0023]
Further, by providing the box 16 and the heat source 17 for heating the inside of the box 16, it is not necessary to raise the temperature of the entire room in which the plastic sorting apparatus is arranged, so that the equipment is not large-scale and the equipment cost is reduced. Is cheap.
[0024]
From here, embodiments of the present invention will be described.
First, a first embodiment will be described with reference to FIGS.
In the plastic sorting apparatus according to the first embodiment , the heat source 17 is a heating lamp or an infrared heater suspended in the upper portion of the box body 16 as the heat source 17 in the basic form described above , whereas the heat source 17 is a metal drum electrode. 5, a radiation heater such as an infrared heater as the heat source 17 as shown in FIG. 3 or a sheath heater attached to the inner circumference of the metal drum electrode 5 as shown in FIG. It was used. Other configurations are the same as those in the basic configuration described above .
[0025]
In this first embodiment , the metal drum electrode 5 is heated from its inner peripheral surface by energizing the radiant heat source, or is heated by a sheath heater in the same manner as in the first embodiment. Even so, PE and PP can be separated with high purity and recovery.
[0026]
Next, a second embodiment of the present invention will be described with reference to FIGS.
In the plastic sorting device according to the second embodiment , the heat source 17 is arranged on the inner peripheral surface side of the metal drum electrode 5 in the first embodiment , and the heat source 17 is a radiation heat source such as an infrared heater, or a metal drum. Whereas a sheath heater attached to the inner peripheral surface of the electrode 5 is used, a radiation heat source such as an infrared heater as the heat source 17 or a sheath heater attached to the inner peripheral surface of the metal drum electrode 5 is used as a high voltage. It is arranged on the electrode 6 side. More specifically, as shown in FIG. 6, a heating box 20 is attached to the back surface of the high voltage electrode 6 and a radiant heat source is arranged in the heating box 20, or a high voltage is applied as shown in FIG. A sheath heater is attached to the back surface of the electrode 6. Other configurations are the same as those in the basic configuration described above .
[0027]
In this second embodiment , the high voltage electrode 6 is heated from the back side by energizing a radiant heat source or heated by a sheath heater, so that the PE can be obtained with high purity and recovery rate even in high humidity. And PP can be separated.
[0028]
In each of the above embodiments, the example in which the plastic piece 1 is mixed as PE and PP and the PE is collected has been shown. However, the present invention is not limited to this, and the same kind as the predetermined plastic piece or the same kind in the triboelectric charge train. Even when applied to plastic, the same effects as the above-described embodiments can be obtained.
[0029]
【The invention's effect】
As is clear from the above description, the present invention is for sorting plastic pieces according to their polarity and charge amount below the friction charging portion for stirring and tribocharging different types of crushed plastic pieces. The sorting unit includes a rotary drum for electrostatically sucking a plastic piece of the same type as the plastic piece in a predetermined plastic piece and a triboelectric charge train , and a circumferential surface of the rotary drum. A separation electrode is provided to form an electrostatic field for separation, a heat source for heating the rotary drum or the separation electrode is provided, and different types of crushed plastic pieces are stirred to polarize the plastic pieces.・ Electrically charge each piece of plastic, and sort the plastic pieces that are frictionally charged according to polarity and amount of charge at the sorting section. It can be recovered reliably high purity and high recovery of the predetermined plastic pieces apart.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a basic form of a plastic sorting apparatus according to the present invention.
FIG. 2 is an overall configuration diagram of a plastic sorting apparatus showing a first embodiment of the present invention.
FIG. 3 is a partially enlarged view when a radiant heat source is used as the heat source of the plastic sorting apparatus according to the first embodiment of the present invention.
FIG. 4 is a partially enlarged view when a sheath heater attached to the inner peripheral surface of the metal drum electrode is used as the heat source.
FIG. 5 is an overall configuration diagram of a plastic sorting apparatus showing a second embodiment of the present invention.
FIG. 6 is a partially enlarged view when a radiant heat source is used as the heat source on the back side of the high voltage electrode as the heat source.
FIG. 7 is a partially enlarged view when a sheath heater attached to the back side of the high voltage electrode is used as a heat source.
FIG. 8 is a graph showing the relative humidity on the horizontal axis and the purity and recovery rate of plastic pieces on the vertical axis .
FIG. 9 is an overall configuration diagram of a conventional plastic sorting apparatus .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plastic piece 3 Friction charging device G Electrostatic separation device 5 Genus drum electrode 6 High voltage electrode 8 First container 9 Second container 15 Heating means 16 Box 17 Heat source

Claims (4)

Different types of crushed plastic pieces are agitated to charge the plastic pieces according to their polarity and charge amount, and when the frictionally charged plastic pieces are sorted according to polarity and charge amount , A rotary drum for electrostatically attracting a plastic piece of the same type as the plastic piece in the plastic piece and the triboelectric charging train , or a sorting for forming a sorting electrostatic field opposite to the peripheral surface of the rotating drum A plastic sorting method characterized by heating an electrode for use. A friction charging unit is provided to stir and charge different types of crushed plastic pieces by friction, and below the friction charging unit, the frictionally charged plastic pieces are sorted according to their polarity and charge amount. The sorting unit includes a rotary drum for electrostatically sucking a plastic piece of the same type as the plastic piece in a predetermined plastic piece and a triboelectric charge train , and a peripheral surface of the rotary drum A plastic sorting apparatus, wherein a sorting electrode for forming a sorting electrostatic field is provided so as to be opposed to the rotary drum or a heat source for heating the rotary drum or the sorting electrode.   3. The plastic sorting apparatus according to claim 2, wherein the heat source is disposed on an inner surface of the rotary drum.   3. The plastic sorting apparatus according to claim 2, wherein the heat source is disposed on the sorting electrode.

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