JP2002177820A - Method and apparatus for feeding and carrying ground plastic and electrostatic separator for ground plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for feeding and carrying a ground plastic simply, inexpensively in a high separation accuracy and to provide an electrostatic separator for a ground plastic. SOLUTION: This separator exhibits an improved separation accuracy by comprising a passage 6 carrying plastics and formed by connecting an air blowing means 1, a heating means 2, and the feed path 5 of a feed means to each other; a means that charges the plastics during their conveying; an electrostatic separation means that separates the plastics according to their types; a plurality of recovery receivers disposed below the electrostatic separation means; a means that decreases the rate of the plastics fed to the electrode, a feed position regulation means, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for electrostatically separating and recovering a plastic mixture composed of two or more types of element bodies having different chemical or physical compositions for each type.

[0002]

2. Description of the Related Art In recent years, with the increase in plastic production, the amount of waste plastic generated has increased. Since plastic has a low specific gravity, its weight is about one sixth of that of iron and cement, but it is considered that it has reached the maximum production volume. Waste plastic is about 40% of emissions
% Are landfilled and about 50% are incinerated. Landfill methods have the problem of reducing the remaining years of landfills, and incineration involves global warming due to the generation of carbon dioxide,
There is a problem of generating harmful gas such as dioxin.

[0003] Recycling of waste plastic is 10%.
The recycling rate of waste plastic, including waste power generation, is 25%, much lower than that of paper and glass bottles. This is largely due to the inability to separate waste plastics by type, promoting recycling,
In order for each material to be used as a suitable recycled material, it is necessary to separate and collect each type of waste plastic.

Therefore, as a method of separating plastic, there are a method of detecting and separating a color and a material using an X-ray or near-infrared sensor, and a method of utilizing a specific gravity difference of plastic.

[0005]

However, the method of using an X-ray or near-infrared sensor is limited to the separation of a large bottle made of the same material, such as a PET bottle, and has various sizes and shapes. It is difficult to separate plastic components by type. Further, in the method utilizing the difference in specific gravity of plastics, it is difficult to separate plastics having a specific gravity close to each other, and since a specific gravity liquid such as water is used, waste liquid treatment is required, and there is a problem that the treatment cost increases. .

The present invention solves the above-mentioned problems of the prior art, and is a method for separating and recovering plastics for each type by using charging of plastics. A simple and inexpensive sorting apparatus with high sorting accuracy is provided. The purpose is to provide.

[0007]

In order to achieve the above object, the present invention provides an electrostatic separation apparatus comprising: a blowing means for conveying plastic; a heating means for heating the blowing air to generate hot air; A supply unit having a supply path for supplying the supply path to the conveyance path is provided.The supply path of the blower unit, the heating unit, and the supply unit of the supply unit are connected to each other, and a conveyance path for conveying the plastic is provided. Means, an electrostatic separation means for introducing the charged plastic into an electrostatic field to classify the plastics by type, and a plurality of collection containers arranged below the electrostatic separation means.

[0008] This makes it possible to separate and recover plastics having a specific gravity close to each other by type, and it is possible to optimally recycle each plastic. Therefore, the amount of plastics that have been landfilled or incinerated as shredder dust so far. Can be greatly reduced, and the burden on the environment can be reduced.

Further, the electrostatic sorting apparatus of the present invention defines a sectional area ratio and a connection angle between the supply path and the transport path, and further provides a rapid contraction tube inside the transport path at the connection section between the supply path and the transport path. This eliminates the need for a supply means such as a screw valve or a rotary valve, so that the electrostatic separation device can be miniaturized and a certain amount of plastic can be stably conveyed.

In addition, warm air is used to transport the plastic,
By using a screw and a cyclone installed in the transport path as the charging means, continuous processing becomes possible, and efficient charging without charge variation becomes possible, and plastic can be separated with high accuracy.

[0011] Furthermore, by providing a means for reducing the falling speed of the plastic, and by installing an introduction plate at a portion (between the electrodes on the entrance side of the pair of electrodes) to be introduced into the electrostatic field of the electrostatic separation means, variation in separation accuracy is improved. By installing the partition plate of the collection container, contamination of impurities can be prevented, and high-purity plastic can be collected.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided a transport section for transporting a crushed plastic article, a charging section for charging the plastic crushed article during transport, and introducing the charged crushed plastic article into an electrostatic field. A separating unit that separates the types of plastics, a plurality of collecting containers disposed below the separating unit, and a plastic electrostatic sorting device that includes a blowing unit for transporting the pulverized plastic; A heating means for producing hot air by heating and a supply means having a supply path for supplying the plastic pulverized material to the conveying path, and connecting the blowing means, the heating means and the supply path of the supply means in order, Is a method of supplying and transporting plastic crushed material, wherein the plastic crushed material is sucked into a transport path by applying a negative pressure to the transport path, and transported by wind force of a blowing means. It is possible to supply and transport the plastic pulverized material without using a feeding means such as a valve and a transporting means such as a belt conveyor, so that the apparatus can be downsized and the plastic pulverized material can be quantitatively and stably transported. Has the effect of being able to.

According to a second aspect of the present invention, there is provided a transport section for transporting a crushed plastic article, a charging section for charging the crushed plastic article during transport, and introducing the charged crushed plastic article into an electrostatic field to separate the plastic crushed articles by type. An electrostatic separation unit, and a plastic electrostatic sorting device including a plurality of collection containers disposed below the electrostatic separation unit, a blowing unit for conveying the plastic pulverized material, and the plastic pulverized material to a conveying path. A supply means provided with a supply path for supplying, and a supply / transportation device for the pulverized plastic material, wherein the supply means of the supply means and the supply path of the supply means are connected in order, utilizing wind power generated by the supply means. To supply and transport the plastic pulverized material by using a rotary valve or screw valve, and supply means such as a belt conveyor. It has an effect that it is possible to reduce the size of the apparatus because it can supply and transport the stick pulverized product.

According to a third aspect of the present invention, there is provided a transport section for transporting a plastic pulverized product, a charging section for charging the plastic pulverized product during transport, and introducing the charged plastic pulverized product into an electrostatic field to separate the plastic pulverized product by type. An electrostatic separation unit, a plastic electrostatic sorting device having a plurality of collection containers disposed below the electrostatic separation unit, an air blowing unit for conveying the plastic pulverized material, and a hot air heated by blowing air. Heating means, and a supply means having a supply path for supplying the plastic pulverized material to the transport path, wherein the blower means, the heating means, and the supply path of the supply means are connected in order. Since it is a supply and transfer device for drying and supplying and transferring plastic pulverized materials at the same time, equipment such as a drying furnace is not required, and processing costs can be reduced. It has the effect of kill.

According to a fourth aspect of the present invention, in the second or third aspect of the present invention, the supply path extends from a plane perpendicular to the air flow direction in the transport path in a direction opposite to the air flow direction.
It is a feeding and conveying device for plastic pulverized material, characterized in that the device is joined by being inclined at an angle of ° to 80 °,
Since the supply path is inclined and joined to the conveyance path, backflow of air (plastic crushed material) to the supply path side can be prevented, so that the plastic crushed substance can be stably supplied to the conveyance path. It has the action of:

In order for the plastic crushed material to drop from the supply path to the transport path by its own weight, the air generated by the blowing means must pass through the transport path without flowing back to the supply path side. When the connection angle of the supply path is set to be greater than 80 ° in a direction opposite to the air flow direction from a plane perpendicular to the air flow direction in the transport path or is connected inclining in the air flow direction, Backflow of air occurs, and the pulverized plastics blow out from the supply path. On the other hand, if the angle is less than 10 °, the crushed plastic material is less likely to fall from the supply path by its own weight, and is clogged in the supply path, so that it cannot be supplied to the transport path.

The invention according to claim 5 is the invention according to claims 2 to 4
In the invention described in any one of the above, a supply / conveyance apparatus for the pulverized plastic material, wherein a sectional area of the supply path is 1/20 to 1/2 times a sectional area of the transport path, This has the effect that the effect of preventing the backflow of air (crushed plastic) can be further enhanced.

Here, the sectional area of the supply path is set to 1 of the sectional area of the transport path.
If the ratio is less than / 20, there is a risk that the plastic crushed material having a large particle diameter may be clogged in the supply path when the cross-sectional area of the conveyance path is small. Therefore, if the conveying path is enlarged, the size of the apparatus is increased, and an expensive blower having a high capacity is required for the blower as the blower. Further, if the cross-sectional area of the supply path is larger than 1/2 times the cross-sectional area of the transport path, there is a danger that air will flow backward in the direction of the supply path and the plastic crushed material will blow out.

According to a sixth aspect of the present invention, in the second or third aspect of the present invention, the inside of the transport path closer to the blower than the supply path and the transport path junction is narrowed in the air flow direction. A plastic pulverized material supply / transportation device characterized by having a rapid shrinkage tube, wherein the ejector effect used when mixing two types of gases is applied. The pressure near the junction decreases due to Bernoulli's theorem due to the increase in the flow velocity of the air discharged from the rapid shrinkage tube, a large negative pressure is generated inside the supply path, and the plastic crushed material is sucked and supplied to the transport path This has the effect of further improving the ability to supply the pulverized plastic to the conveying path.

According to a seventh aspect of the present invention, in the second, third or sixth aspect of the present invention, it is preferable that the cross-sectional area of the outlet of the rapid-shrink tube is 1/100 to 1/2 times the cross-sectional area of the conveying path. It is a supply and transport device for plastic pulverized materials, which can enhance the effect of preventing the backflow of plastic pulverized materials due to the pressure loss of the screw and cyclone that are the charging means, and by changing the cross-sectional area ratio It has the effect of being able to freely change the wind pressure and wind speed for transporting the crushed plastic.

If the cross-sectional area of the outlet of the rapid-shrink tube is less than 1/100 times the cross-sectional area of the conveying path, the conveying capacity of the plastic pulverized material is reduced due to the pressure loss, and the blower is overloaded. Cause. Also, 1/2
If it is larger than double, the ejector effect is reduced and the supply capacity to the transport path is reduced.

According to an eighth aspect of the present invention, in accordance with the third aspect of the present invention, the temperature of the hot air heated by the heating means is controlled within a range of 70 to 100 ° C. A transport device that removes water inside the transport path due to condensation and removes moisture adsorbed on pulverized plastics, thereby increasing the amount of charge on the plastic and improving the separation accuracy. .

If the temperature of the hot air is set to less than 70 ° C., the effect of removing water adsorbed on the inside of the conveying pipe and the pulverized plastic material is reduced, the charge amount is reduced, and the separation accuracy is deteriorated. Conversely, if the temperature is set to 100 ° C. or higher, thermal deterioration occurs depending on the plastic, and the characteristics of the remolded product are significantly reduced.

According to a ninth aspect of the present invention, there is provided a transport section for transporting a crushed plastic article, a charging section for charging the crushed plastic article during transport, and introducing the charged crushed plastic article into an electrostatic field to separate the crushed plastic article by type. An electrostatic separation unit, and a plastic electrostatic separation device including a plurality of collection containers arranged below the electrostatic separation unit, wherein the charging means is provided with a screw blade and a cyclone arranged partially or entirely within the transport path. It is an electrostatic sorting device for plastic pulverized material characterized by being constituted by, and it is possible to more strongly charge the plastic pulverized material charged by collision and friction with the screw blade by the cyclone,
By charging the plastic pulverized material that is not sufficiently charged by the screw blade with the cyclone, the plastic pulverized material having a small charge variation and a small charge amount is eliminated, so that the separation accuracy can be improved.

According to a tenth aspect of the present invention, in accordance with the ninth aspect of the present invention, the outer diameter of the screw blade is 1/2 to 1 times the inner diameter of the conveying path, and the electrostatic discharge of the pulverized plastic material is performed. This is a sorting device, which has the effect of reducing the variation in charge amount and improving the separation accuracy by sufficiently colliding and contacting the crushed plastic with the screw blade.

The charge amount of the pulverized plastic material increases as the frequency of collision and friction increases. If the outer diameter of the screw blade is less than half the inner diameter of the transport path, the frequency of collision / friction will decrease and the amount of charge will decrease, and the frequency of collision / friction will vary, causing variation in the amount of charge and separation accuracy. Is reduced. Further, since the screw blade is provided in the transport path, the outer diameter of the screw blade cannot be made larger than one time the inner diameter of the transport path.

An eleventh aspect of the present invention is the crushed plastic product according to the ninth or tenth aspect, wherein the blade pitch of the screw blade is 1/2 to 5 times the outer diameter of the screw blade. The electrostatic sorter has the function of sufficiently crushing and contacting the plastic crushed material with the screw blades and preventing backflow of the plastic crushed material in the supply path.

Here, when the blade pitch of the screw blade is smaller than 1/2 of the outer diameter of the screw blade, the static pressure increases due to the installation of the screw blade, and there is a risk of air backflow to the supply path. On the other hand, if it is larger than 5 times, it is necessary to arrange long screw blades in the conveying path to increase the frequency of collision and contact, which increases the size of the apparatus and increases the static pressure, so that air is supplied to the supply path. There is a danger that the backflow plastic crushed product will blow out from the supply channel.

According to a twelfth aspect of the present invention, in the first aspect of the present invention, the charge amount of the crushed plastic charged by the charging means is ± 0.001 to 0.001.
An electrostatic separator for pulverized plastics, characterized in that it has a charge of 10 nC / cm ² , and a high-purity plastic can be recovered because separation accuracy can be improved by setting the charge amount of the plastic within the above range. It has the effect of being able to.

In electrostatic separation, the separation accuracy improves as the horizontal movement distance of the crushed plastic in the electrostatic field between the pair of electrodes to which a voltage is applied increases. ±
If it is less than 0.001 nC / cm ² , the moving distance in the horizontal direction is reduced, and the separation accuracy is deteriorated. As a result, the purity of the collected pulverized plastic is also deteriorated. Further, it is difficult to obtain a charge amount larger than ± 10 nC / cm ² by friction charging.

According to a thirteenth aspect of the present invention, a transport section for transporting a plastic pulverized material, a charging section for charging the plastic pulverized material during transportation, and introducing the charged plastic pulverized material into an electrostatic field to separate them by type In a plastic electrostatic sorting device including a static separation unit to be cleaned and a plurality of collection containers disposed below the electrostatic separation unit, the plastic crushed material charged by the charging unit is introduced into the electrostatic field of the electrostatic separation unit. A device for reducing the introduction speed, which is an electrostatic sorting device for crushed plastics, characterized in that the falling speed of the crushed plastics between the electrodes is reduced, so that the electrostatic field for a longer time is reduced. Because of the influence, the moving distance in the horizontal direction increases, and the separation accuracy can be improved.

According to a fourteenth aspect of the present invention, there is provided a transport section for transporting a crushed plastic article, a charging section for charging the crushed plastic article during transport, and introducing the charged crushed plastic article into an electrostatic field to separate each type. In a plastic electrostatic separation device having a plurality of collection containers arranged below the electrostatic separation unit and the electrostatic separation unit, a plastic pulverized material is placed at an entrance side between a pair of opposed electrodes of the electrostatic separation unit. This is an electrostatic sorting device for pulverized plastics, characterized by having a means for defining the drop position. The precision of separation can be ensured because the pulverized plastics charged by the charging means can be reliably put into a predetermined position between the electrodes. Can be improved. In addition, even if the same charging method is used, a difference in charge amount occurs depending on the type of plastic. Therefore, when separating pulverized plastic materials in which two or more types having different charge amounts are mixed, the position of the introduction plate between the electrodes is adjusted by adjusting the position of the introduction plate. It can be changed, and as a result, the separation accuracy can be improved.

That is, in the separation of a mixture of a plastic crushed material having a large charge and a plastic crushed material having a small charge, when the plastic crushed material is introduced from the center between the electrodes, the plastic crushed material having a large charge does not cause any problem. On the other hand, a plastic pulverized material having a small charge amount has a small moving distance in the horizontal direction, so that the recovery rate is deteriorated. Therefore, by bringing the introduction plate closer to the electrode side for collecting the small amount of plastic pulverized matter, the pulverized plastic having a large amount of charge can be collected in a desired collection container even if the moving distance in the horizontal direction is small. Since the moving distance in the horizontal direction is large and can be collected in the collection container on the opposite side, separation accuracy can be improved.

According to a fifteenth aspect of the present invention, in the invention according to the fourteenth aspect, the falling position defining means is a pair of opposedly disposed introduction plates, and the length of the electrode from the upper side of the pair of opposedly arranged electrode entrances. An electrostatic separator for plastic pulverized material, wherein the plastic pulverized material is inserted between the electrodes within the dimensions described above, whereby the plastic pulverized material is inserted between the electrodes. This has the effect that it can be reliably dropped between the electrodes without jumping out of the electrode.

If the insertion length of the introduction plate into the entrance-side electrode is less than 1/40 of the electrode length, the pulverized plastic material will jump out of the space between the electrodes due to the electrostatic field in the outward direction of the electrode. On the other hand, if it is larger than 1/4, the time during which the plastic pulverized material is affected by the electrostatic field generated between the electrodes is reduced, and the moving distance in the horizontal direction is reduced. As a result, it is necessary to increase the length of the electrode, which causes an increase in the size of the device.

The invention according to claim 16 is the invention according to claim 14 or 15, wherein the introduction plate is an insulator such as paper, resin, wood or ceramic. This is a sorting device, and has an effect that discharge to the introduction plate can be prevented by using an insulator for the introduction plate.

The dielectric breakdown of air is 10 kV / cm,
When a voltage higher than this is applied between the electrodes, the electrostatic field decreases due to the discharge, and the separation accuracy deteriorates. Therefore, if a conductive material is used for the introduction plate inserted between the electrodes, there is a risk of discharging between the electrodes and the introduction plate, so that a high voltage cannot be applied and the separation accuracy deteriorates.

According to a seventeenth aspect of the present invention, a transport section for transporting a plastic pulverized material, a charging section for charging the plastic pulverized material during transportation, and introducing the charged plastic pulverized material into an electrostatic field to separate them by type In a plastic electrostatic separation device having an electrostatic separation unit to be separated and a plurality of collection containers arranged below the electrostatic separation unit, a unit for removing a plastic pulverized substance attached to an electrode surface of the electrostatic separation unit is provided. It is an electrostatic sorting device for pulverized plastics, characterized in that it can prevent the electrostatic force of the electrostatic field between the electrodes from decreasing, so that the recovery rate and purity do not decrease even in continuous processing. This has the effect that good separation accuracy can be ensured.

The charged plastic fine powder moves to and adheres to the electrode surface of the opposite polarity due to electrostatic force between the electrodes. When the fine powder adheres to the electrode surface, the electrostatic force decreases, the moving distance of the plastic crushed material in the horizontal direction decreases, and the separation accuracy deteriorates. Accordingly, stable separation accuracy can be obtained by removing fine powder on the electrode surface periodically by the removing means.

According to an eighteenth aspect of the present invention, in the above-mentioned seventeenth aspect, it is preferable that a voltage of a reverse polarity is applied to the electrode of the electrostatic separation unit to remove the crushed plastic adhered to the electrode surface. This is a device for electrostatically sorting plastic pulverized materials, which can remove plastic adhering to the electrode surface without using a function of hitting the electrode or sweeping the electrode surface with a wiper.

The positively charged plastic fine powder adheres to the electrode to which a negative voltage is applied, but momentarily reverse polarity (positive)
Is applied, the plastic fine powder is separated from the electrode surface by the electrostatic force in the opposite direction. Thereafter, when the voltage application is stopped, the fine powder falls by its own weight and can be removed from the electrode surface. Similarly, negatively charged fine powder can be removed by instantaneously applying a reverse polarity (negative) voltage to the electrode to which a positive voltage is applied.

According to a nineteenth aspect of the present invention, a transporting section for transporting a plastic pulverized product, a charging section for charging the plastic pulverized product during transport, and introducing the charged plastic pulverized product into an electrostatic field to separate them by type. An electrostatic separation unit, and a plastic electrostatic separation device including a plurality of collection containers disposed below the electrostatic separation unit, wherein a partition plate is provided between the collection containers, This is an electrostatic sorting device, which has the effect of preventing mixing of plastic pulverized material that has bounced off the bottom surface of the collection container and collecting high-purity plastic.

According to a twentieth aspect of the present invention, there is provided an electrostatic sorting apparatus for a pulverized plastic material according to the nineteenth aspect, wherein the height of partition plates arranged between the plurality of collection containers is different. Yes, by increasing the height of the partition plate on the side of the collection container from which plastics requiring high purity are collected, the effect of preventing the mixing of plastic crushed material that bounces off the bottom of the collection container becomes higher, and the purity It has the effect that high plastics can be recovered.

According to a twenty-first aspect of the present invention, in the invention of the nineteenth or twentieth aspect, the partition plate is installed at an angle of 10 ° to 45 ° from the plane perpendicular to the bottom surface of the collection container toward the electrode center. It is an electrostatic sorting device for plastic pulverized materials characterized by the fact that the plastic pulverized material bounced off the bottom of the collection container is more effectively prevented from climbing over the partition plate and being collected in another collection container. It has the effect of being able to recover plastics with a high density.

What bounces off the bottom of the collecting container and gets over the partition plate is a crushed plastic material falling near the partition plate. Therefore, by arranging the partition plate at an angle, the plastic crushed material falling near the partition plate collides with the side surface of the partition plate and falls to the far side of the container, so that it does not get over the partition plate. Further, by installing the partition plate at an angle, the falling distance can be secured without increasing the height of the partition plate. When the inclination angle of the partition plate is smaller than 10 °, the frequency of collision with the side of the partition plate is small, and the effect is small. When the inclination angle of the partition plate is larger than 45 °, the frequency of collision with the side of the partition plate is increased. Since there is a risk of colliding with the side surface and getting over the adjacent partition plate, it is preferable to set the inclination angle of 10 ° to 45 °.

An embodiment of the present invention will be described below with reference to FIGS. Here, the same components are denoted by the same reference numerals.

(Embodiment) FIG. 1 is an explanatory view of an electrostatic sorting apparatus according to an embodiment of the present invention. As shown in FIG.
The electrostatic sorting device according to the embodiment is a device that separates and collects each plastic element object by type from a plastic mixture in which two or more types of crushed plastic crushed materials, which are materials to be sorted, are mixed. The injected plastic mixture is quantitatively supplied from the supply path 5 to the transport path 6 by the straight-ahead feeder 4, and the blower 1
And the hot air generated by the heater 2 are transported to the charging unit through the transport path 6.

Here, FIG. 2 is a schematic diagram in which the supply path is joined in a direction opposite to the flow direction of air from a plane perpendicular to the conveyance path, and the joint between the supply path 5 and the conveyance path 6 shown in FIG. It is shown. The supply path 5 is joined at an angle of θa in a direction opposite to the air flow direction α from a plane perpendicular to the air flow direction α generated by the blower 1. FIG. 3 is a schematic diagram in which the supply path is joined perpendicular to the transport path. As shown in FIG. 3, the supply path 5 is joined to the transport path 6 perpendicular to the air flow direction α, and FIG. FIG. 4 is a schematic diagram in which supply paths are joined in a direction of air flow from a vertical plane, and as shown in FIG.
In the case where the joining is performed in such a manner as to be inclined from the plane perpendicular to the air flow direction α, the air is blown out from the supply path 5, so that the pulverized plastic cannot be supplied to the transport path 6. Therefore, as shown in FIG. 2, the supply path 5 must be joined by being inclined in a direction opposite to the air flow direction α from a plane perpendicular to the air flow direction α generated by the blower 1. Further, if the inclination angle θa is 10 ° to 80 °, clogging of the plastic crushed material in the supply path and blowing of the plastic crushed material due to blowing of air are unlikely to occur, but preferably 20 ° to 50 °. It is desirable to join at an inclined angle. Further, the cross-sectional area of the supply path 5 is set to 1
By increasing the ratio from / 20 to 倍, the pulverized plastic can be smoothly supplied to the transport path 6.

However, if there is an obstacle in the transport pipe that hinders the flow of air, the pressure inside the transport pipe increases, and if the pressure is large, the joining angle of the supply path 5 or the sectional area of the supply path 5 will increase. Only by adjusting the cross-sectional area ratio of the conveying path 6, there is a possibility that the inside of the supply path 5 does not become a negative pressure and the pulverized plastic material blows out. Therefore, FIG. 5 is a schematic diagram in which a quick-shrink tube is installed in the transport path, and as shown in FIG. 5, the inside of the transport path 6 closer to the blower 1 than the junction between the supply path 5 and the transport path 6
By arranging the rapid contraction tube 16 narrowing in the air flow direction α, the suction force of the plastic crushed material can be increased. This is an application of the ejector effect used when mixing two types of gases, where the flow velocity at point _A is V _A , the pressure is P _A , the velocity at point _B is V _B ,
Assuming that the pressure is P _B , the flow velocity V _{B of} the air discharged from the rapid contraction tube 16 is larger than the flow velocity _VA (V _B > V _A ), and the pressure near the junction is determined by the energy conservation law of Bernoulli's theorem. P _B decreases and the negative pressure inside the supply path 5 increases, so that the plastic pulverized material can be more strongly sucked and supplied to the transfer path 6. Here, the exit cross-sectional area of the rapid contraction tube 16 needs to be 1/100 to 1/2 times the cross-sectional area of the conveying path, and by changing this value, the wind pressure and the wind speed for conveying the plastic pulverized material can be freely adjusted. It is possible to change.

The temperature of the hot air is measured by a thermocouple installed at the outlet of the heater 2 and is controlled to a set temperature of about ± 2 ° C. by a temperature controller. If the temperature of the hot air is lower than 70 ° C., the effect of removing the moisture adsorbed inside the transfer tube and the plastic decreases, and the charge amount of the pulverized plastic becomes small, thereby deteriorating the separation accuracy. Conversely, if the temperature is set to 100 ° C. or higher, thermal degradation occurs depending on the plastic, and the characteristics of the remolded product are significantly reduced. Therefore, it is desirable to control the temperature in the range of 70 to 100 ° C. Here, the heater 2 is connected after the blower 1 to generate hot air. However, when the heater 2 is not connected, it is necessary to dry the plastic mixture to be put into the hopper 3 in a drying furnace in advance to remove adsorbed moisture. is there.

Next, the charging section is composed of a screw blade 7 and a cyclone 8 arranged partially or entirely inside the transport path. First, the plastic mixture is charged by collision and friction with the screw blade 7 and supplied to the cyclone 8 together with hot air. The plastic mixture supplied to the cyclone 8 is further charged by dropping while spirally contacting the inner wall of the cyclone 8 and discharged from the rotary valve 9 below the cyclone 8. The hot air becomes an updraft in the middle of the cyclone 8 and is discharged from the discharge unit 11.

Here, the screw blade 7 and the cyclone 8
It is desirable that the charging sequence is located at the middle portion or the same material with respect to the material to be sorted, but the charging sequence with respect to the sorting material is located at the middle portion on the surface of the screw blade 7 and the inner wall of the cyclone 8. The material to be located or the same material may be applied or pasted. Although all insulating materials can be used for the screw blade 7 and the cyclone 8, synthetic fibers such as cotton, cotton and polyester, and metals such as stainless steel, copper, chromium, and nickel can also be used.

The screw blade 7 and the cyclone 8
The amount of charge of the pulverized plastic charged by the method is ± 0.
If it is less than 001 nC / cm ² , the moving distance in the horizontal direction becomes small and the separation accuracy deteriorates.
/ Cm ² , it is difficult to obtain a charge of more than 0.001 nC / c.
it is necessary that the m ² is ± 10nC / cm ^2.

Next, a mixture of the positively charged plastic pulverized material 13b and the negatively charged plastic pulverized material 13a is discharged from the cyclone 8 according to the charging sequence, and the speed is reduced by a falling speed reducing means (not shown). The plastic mixture is introduced between the electrodes 12a and 12b through the space between the introduction plates 10a and 10b for guiding the plastic mixture provided on the entrance side of the electrodes 12a and 12b arranged opposite to each other.

Here, as a means for reducing the falling speed of the plastic mixture, there is a method of blowing air from below, or a method of installing a sieve having an opening larger than the particle size of the pulverized material below the rotary valve 9 of the cyclone 8. However, the present invention is not limited to this, and any means for reducing the falling speed of the plastic mixture may be used.

Next, positive and negative voltages are applied to the electrodes 12a and 12b, respectively. The negatively charged plastic crushed material 13a is on the electrode 12a side, and the positively charged plastic crushed material 13b is on the electrode 12b side. And are separated and collected in the collection containers 15a and 15b, respectively. Here, the plastic mixture having a small charge amount is collected in the collection container 15.
c, which can be returned to the hopper 3 and sorted again.

The introduction plates 10a and 10b are used to reliably supply the plastic mixture to a predetermined position between the electrodes 12a and 12b, and charge the positively charged plastic pulverized material 13b and the negatively charged plastic pulverized material 13a. FIG. 6 is a schematic view of a case where an introduction plate is installed when a mixture having the same absolute value is separated as shown in FIG. 6, and is installed at a center position between the electrodes 12a and 12b, and is positively charged. When the absolute value of the charge amount of the crushed plastic crushed material 13b is smaller than the absolute value of the charge amount of the negatively charged plastic crushed material 13a, that is, when separating a plastic mixture having a difference in the absolute value of the charge amount, FIG. As shown in FIG. 7, FIG. 7 is a schematic diagram when the position of the introduction plate is shifted, and the pulverized plastic material 13b having a small absolute value of the charge amount is shown.
Is introduced on the electrode side (12b in this case) where
The separation accuracy can be improved by displacing the installation positions of a and 10b. In addition, the introduction plate 10
The insertion plate is not installed in FIG. 8 as shown in FIG. 8 without deteriorating the separation accuracy by inserting 1/40 to 1/4 times the electrode length from the upper part on the entrance side between the electrodes 12a and 12b. FIG.
a, 13b can be prevented from falling outside between the electrodes 12a, 12b.

Further, between the collection containers 15a and 15c, 15
Partition plates 14a and 14b are provided between b and 15c, respectively, so that the plastic crushed material rebounding from the bottom of the collection container does not enter the adjacent collection container. Higher purity plastic can be collected by installing the partition plates 14a and 14b at an angle from the surface perpendicular to the bottom surface of the collection container toward the center between the electrodes, or by increasing the number of collection containers.

[0059]

Next, specific examples of the present invention will be described. It should be noted that the numerical values shown in the embodiments are examples of various types that can be selected, and the present invention is not limited to these.

(Example 1) In the electrostatic separation apparatus of the embodiment shown in FIG. 1, PP (polypropylene) having a product number of 8400R manufactured by Calp Industry Co., Ltd. The result of a separation experiment of a mixture containing 20% of TSE397 silicone is shown.

The joint between the supply path 5 and the transfer path 6 is connected at θ = 30 ° in FIG. 5, the cross-sectional area of the supply path 5 is 1/10 of the cross-sectional area of the transfer path 6, The exit cross section was set to 1/10 of the conveyance path cross section. The temperature of the hot air generated by the blower 1 and the heater 2 is controlled to 90 ± 2 ° C.

Next, the conveying path 6, the screw blades 7 and the cyclone 8 are made of stainless steel whose charging sequence is in the middle position between silicone and PP. (Not shown) was installed below the rotary valve 9 of the cyclone 8. The outer diameter of the screw blade 7 is 4/5 times the inner diameter of the conveying path, and the blade pitch is twice the outer diameter of the screw blade 7. The introduction plates 10a and 10b are made of 1 mm thick Mitsui Toatsu Chemical Co., Ltd. slate PVC low polymerization degree PVC.
(Polyvinyl chloride) is inserted and installed at the center position between the electrodes 12a and 12b 1/10 times the electrode length, and partitioned between the collection containers 15a and 15c and between the collection containers 15b and 15c. The plates 14a and 14b were set at an angle of 20 ° from the plane perpendicular to the bottom surface of the collection container toward the center between the electrodes.

The mixture of the pulverized product of PP and the pulverized product of silicone is charged with negative PP and positively charged silicone according to the charging order due to collision and friction with the screw blade 7 and the cyclone 8. Is discharged and passes between the introduction plates 10a and 10b.
Introduced between 12b. Here, the negatively charged PP crushed material 13a moves to the electrode 12a to which a positive voltage is applied, and the positively charged silicone crushed material 13b moves to the electrode 12b to which a negative voltage is applied, and the collection containers 15a and 15b, respectively.
Will be collected. In addition, the PP pulverized material 13 having a small charge amount
a, Both of the pulverized silicone materials 13b were collected in the collection container 15c and returned to the hopper 3 for sorting again. As a result, PP having a purity of 99% or more could be recovered in the recovery container 15a at a recovery rate of 90% or more.

(Example 2) FIG. 9 shows the effect of the screw blade 7 and the cyclone 8, which are charging means, in separating and recovering a mixture in which 20% of silicone is mixed into PP (polypropylene) pulverized to a particle size of 7 mm or less. It is a thing. Conditions other than the charging unit are the same as those in the first embodiment, and a description thereof will not be repeated.

FIG. 9 shows that the recovery rate of PP is 50% and the purity is 85% when only the transport path 6 is used. However, the recovery rate of PP is improved to 80% and the purity is 95% by disposing the screw blade 7. Further, by arranging the cyclone 8, a recovery rate of PP of 90% and a purity of 99% could be achieved.

(Embodiment 3) FIG. 10 shows the results of a separation experiment showing the effects of the speed reducing means (not shown) and the introduction plates 10a and 10b. The speed reducing means is the same as in the first embodiment.
A 0 mm stainless steel vibrating sieve was used. Further, the separation sample and other conditions are the same as those in the first embodiment, and the description is omitted here.

FIG. 10 shows that the speed reducing means and the introduction plate 10
When a and 10b are not installed, the recovery rate of PP is 60% and the purity is 85%. However, by installing a vibrating sieve as a speed reducing means, the recovery rate of PP is improved to 70% and the purity to 95%. Further, by disposing the introduction plates 10a and 10b, it was possible to achieve a PP recovery rate of 90% and a purity of 99%.

(Example 4) FIG. 11 is a diagram showing a change in the PP recovery rate showing the effect of removing dust adhering to the electrode, and FIG. 12 is a diagram showing a change in PP purity showing the effect of removing dust adhering to the electrode. , 12b show the results of a separation experiment showing the effect of the dust removing means attached to the surface, showing the relationship between the treatment time and the PP recovery and purity. Further, the separation sample and other conditions are the same as those in the first embodiment, and the description is omitted here.

Here, the negatively charged PP fine powder 13a adheres to the electrode 12a to which a positive voltage is applied, and the positively charged silicone fine powder 13b adheres to the negative voltage to the electrode 12b. After a negative voltage is applied to the electrode 12a and a positive voltage is applied to the electrode 12b, the application of the voltage is stopped to remove the voltage from the electrode surface. Reverse voltage was applied at 5 minute intervals, and the voltage application stop time was 3 seconds. Before applying the reverse polarity voltage, the plastic crushed material from the straight feeder 4 to the supply path 5 is applied so that the plastic crushed material is not supplied between the electrodes while the voltage application and the voltage application of the opposite polarity are stopped. Is controlled to stop supply.

As can be seen from FIGS. 11 and 12, when dust adhering to the electrode surface is not removed, the PP
While the recovery rate sharply decreases from 90 to 65% and the PP purity sharply decreases from 99 to 85%, when dust is removed, the PP recovery rate is 88 to 90% and the PP purity is 95 to 99%. I was able to.

[0071]

As described above, according to the electrostatic separation device of the present invention, the following effects can be obtained.

(1) Blowing means for transporting the pulverized plastic material and supply means having a supply path for supplying the pulverized plastic material to the transport path are provided, and the blowing means and the supply path of the supply means are connected in order. A supply / transportation device for a plastic pulverized material, which supplies and conveys the plastic pulverized material using the wind force generated by a blowing means, such as a supply means such as a rotary valve and a screw valve, and a belt conveyor. Since the plastic pulverized material can be supplied and transported without using a transporting means such as the above, the apparatus can be downsized and the plastic pulverized material can be quantitatively and stably transported.

Further, a heating means for heating the air to generate hot air is provided between the blowing means and the supplying means, and the blowing means, the heating means and the supply path of the supplying means are connected in order, so that the plastic pulverized material is obtained. Since the drying, supply, and transport can be performed at the same time, equipment such as a drying furnace is not required, and the processing cost can be reduced.

(2) At the junction between the supply path and the transfer path, the joining angle of the supply path, the ratio of the cross-sectional area of the supply path to the cross-sectional area of the transfer path are defined, and a rapid contraction tube is arranged inside the transfer path to make a sudden change. By defining the ratio of the cross-sectional area of the outlet of the shrinking tube to the cross-sectional area of the conveying path, the force for sucking the pulverized plastic into the conveying path can be increased. Also, by changing the ratio of the cross-sectional area of the exit of the rapid-shrink tube to the cross-sectional area of the conveying path, it is possible to freely adjust the wind pressure and the wind speed for conveying the pulverized plastic.

(3) By forming the charging means with a screw blade and a cyclone disposed partially or entirely inside the transport path, the plastic pulverized material charged by the collision and friction with the screw blade is more strongly charged by the cyclone. In addition, since the plastic pulverized material that is not sufficiently charged by the screw blade can be charged by the cyclone, there is no plastic pulverized material having a small charge variation and charge amount, and the separation accuracy can be improved.

(4) When introducing the pulverized plastic into the electrostatic field of the electrostatic separation unit, a means for reducing the introduction speed is provided to reduce the falling speed of the pulverized plastic between the electrodes. Due to the influence of the electrostatic field for a long time, the moving distance in the horizontal direction increases, and the separation accuracy can be improved.

(5) By providing means for defining the falling position of the crushed plastic material at the entrance side between the pair of opposing electrodes of the electrostatic separation unit, the crushed plastic material charged by the charging means can be reliably transferred between the electrodes. Separation accuracy can be further improved because it can be put into a predetermined position.

(6) By providing a means for removing the pulverized plastic adhered to the electrode surface, it is possible to prevent the electrostatic force from being reduced in the electrostatic field between the electrodes, so that the recovery rate and purity are reduced even in continuous processing. Good separation accuracy can be stably secured without any problem.

(7) By providing a partition plate between the collecting containers and defining the height and the installation angle of the partition plate, it is possible to prevent mixing of the pulverized plastics rebounding from the bottom surface of the collecting container and to collect high-purity plastic. it can.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an electrostatic sorting device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram in which a supply path is joined in a direction opposite to a flow direction of air from a plane perpendicular to a transport path.

FIG. 3 is a schematic diagram in which a supply path is joined perpendicularly to a transport path.

FIG. 4 is a schematic diagram in which a supply path is joined in a direction of air flow from a plane perpendicular to a transport path.

FIG. 5 is a schematic diagram in which a quick-shrink tube is installed in a transport path.

FIG. 6 is a schematic diagram when an introduction plate is installed.

FIG. 7 is a schematic view when the position of the introduction plate is shifted.

FIG. 8 is a schematic diagram when no introduction plate is installed.

FIG. 9 is a diagram showing the results of a separation test showing the effects of screw and cyclone charging.

FIG. 10 is a diagram showing the results of a separation test showing the effects of the speed reducing means and the introduction plate.

FIG. 11 is a diagram showing a change in PP recovery rate showing an effect of removing dust adhering to an electrode.

FIG. 12 is a diagram showing a change in PP purity showing an effect of removing dust adhering to an electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blower 2 Heater 3 Hopper 4 Straight feeder 5 Supply path 6 Transport path 7 Screw blade 8 Cyclone 9 Rotary valve 10a, 10b Introducing plate 11 Discharge part 12a, 12b Electrode 13a, 13b Plastic crushed material 14a, 14b Partition plate 15a, 15b 15c Collection container 16 Rapid shrink tube

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65G 53/60 B65G 53/60 (72) Inventor Noriaki Seki 1006 Kazuma, Kazuma, Kazuma, Osaka Matsushita Electric Industrial F term (reference) 3F047 AA14 CC11 DB01 4D054 GA01 GA09 4F301 BF03 BF26 BG16 BG21 BG44

Claims (21)

[Claims] 1. A conveying section for conveying a crushed plastic,
A charging unit for charging the plastic pulverized material during transportation, an electrostatic separating unit for introducing the charged plastic pulverized material into an electrostatic field and separating the separated by type, and a plurality of collection containers arranged below the electrostatic separating unit In the electrostatic sorting device for plastics provided with, a blowing means for conveying the plastic pulverized material, and a supply means having a supply path for supplying the plastic pulverized material to the conveying path are provided, and the blowing means and the supply means are provided. A method for supplying / conveying a plastic pulverized material, wherein a plastic pulverized material is connected to a supply path in order, a negative pressure is applied to the inside of the supply path, the plastic pulverized material is sucked into the conveyance path, and the plastic pulverized substance is conveyed by the wind force of the blowing means. 2. A conveying section for conveying a crushed plastic,
A charging unit for charging the plastic pulverized material during transportation, an electrostatic separating unit for introducing the charged plastic pulverized material into an electrostatic field and separating the separated by type, and a plurality of collection containers arranged below the electrostatic separating unit In the electrostatic sorting device for plastics provided with, a blowing means for conveying the plastic pulverized material, and a supply means having a supply path for supplying the plastic pulverized material to the conveying path are provided, and the blowing means and the supply means are provided. A supply / transportation apparatus for a pulverized plastic product, which is connected to a supply path in order. 3. A conveying section for conveying a crushed plastic,
A charging unit for charging the plastic pulverized material during transportation, an electrostatic separating unit for introducing the charged plastic pulverized material into an electrostatic field and separating the separated by type, and a plurality of collection containers arranged below the electrostatic separating unit In a static electricity sorting apparatus for plastics comprising: a blower for conveying a plastic pulverized material, a heating means for heating air to make hot air and a supply path for supplying a plastic pulverized material to a conveying path. Means for supplying and conveying the pulverized plastic material, wherein the blower means, the heating means, and the supply path of the supply means are connected in order. 4. The supply path is formed in a direction perpendicular to the direction of air flow in the conveying path by 10 ° to a direction opposite to the direction of air flow.
The supply / transport apparatus of a plastic pulverized product according to claim 2 or 3, wherein the plastic pulverized material is bonded at an angle of 80 °. 5. The supply of the crushed plastic product according to claim 2, wherein a cross-sectional area of the supply path is 1/20 to 1/2 times a cross-sectional area of the transport path.・ Transport device. 6. A rapid-shrink tube narrowed in a flow direction of air is disposed inside a transport path on the side of the blower means relative to a junction between the supply path and the transport path. 4. The supply / transportation device for a pulverized plastic product according to 3. 7. The supply of the plastic pulverized product according to claim 2, wherein an outlet cross-sectional area of the rapid-shrink tube is 1/100 to 1/2 times the cross-sectional area of the conveying path.・ Transport device. 8. The apparatus for feeding and conveying a plastic pulverized product according to claim 3, wherein the temperature of the hot air heated by the heating means is controlled in a range of 70 to 100 ° C. 9. A transport section for transporting pulverized plastics,
A charging unit for charging the plastic pulverized material during transportation, an electrostatic separating unit for introducing the charged plastic pulverized material into an electrostatic field and separating the separated by type, and a plurality of collection containers arranged below the electrostatic separating unit Wherein the charging section is constituted by a screw blade and a cyclone disposed partially or entirely within the transport path. 10. The apparatus according to claim 9, wherein the outer diameter of the screw blade is 1/2 to 1 times the inner diameter of the conveying path. 11. The apparatus according to claim 9, wherein the blade pitch of the screw blade is 1/2 to 5 times the outer diameter of the screw blade. 12. The statically ground plastic pulverized product according to claim 9, wherein a charge amount of the plastic pulverized material charged by the charging means is ± 0.001 to 10 nC / cm ^2. Electric sorting equipment. 13. A transport section for transporting a plastic crushed product, a charging section for charging the plastic crushed product during transport, an electrostatic separation section for introducing the charged plastic crushed product into an electrostatic field and separating it by type. In a plastic electrostatic sorting device including a plurality of collection containers disposed below the electrostatic separation unit, when introducing the plastic pulverized material charged by the charging unit into the electrostatic field of the electrostatic separation unit, An apparatus for electrostatically sorting pulverized plastics, comprising means for reducing the speed. 14. A transport section for transporting a plastic pulverized product, a charging section for charging the plastic pulverized product during transport, an electrostatic separating section for introducing the charged plastic pulverized product into an electrostatic field and separating the plastic pulverized product by type. In a plastic electrostatic separation device including a plurality of collection containers arranged below the electrostatic separation unit, a falling position of the plastic pulverized material is defined on an entrance side between a pair of opposed electrodes of the electrostatic separation unit. A device for electrostatically sorting pulverized plastics, characterized by comprising means. 15. The apparatus according to claim 15, wherein said drop position defining means is a pair of opposedly disposed introducing plates, and is inserted 1/40 to 1/4 times the electrode length from above the entrance side between the pair of opposedly disposed electrodes. The apparatus for electrostatically sorting pulverized plastic products according to claim 14. 16. The apparatus according to claim 14, wherein the introduction plate is an insulator such as paper, resin, wood, or ceramic. 17. A transport section for transporting a plastic crushed product, a charging section for charging the plastic crushed product during transport, an electrostatic separation section for introducing the charged plastic crushed product into an electrostatic field and separating it by type. In a plastic electrostatic separation device including a plurality of collection containers disposed below the electrostatic separation unit, a unit for removing a plastic crushed substance attached to an electrode surface of the electrostatic separation unit is provided. Sorting machine for crushed plastics. 18. The electrostatic sorting of a crushed plastic product according to claim 17, wherein a voltage of a reverse polarity is applied to the electrode of the electrostatic separation unit to remove the crushed plastic material attached to the electrode surface. apparatus. 19. A transport section for transporting a crushed plastic article, a charging section for charging the crushed plastic article during transport, an electrostatic separating section for introducing the charged crushed plastic article into an electrostatic field and separating the same by type. A plastic electrostatic sorting device comprising a plurality of collection containers disposed below the electrostatic separation unit, wherein a partition plate is provided between the collection containers. 20. The apparatus according to claim 19, wherein the height of partition plates arranged between the plurality of collection containers is different. 21. The plastic pulverized product according to claim 19, wherein the partition plate is installed at an angle of 10 ° to 45 ° from a plane perpendicular to the bottom surface of the collection container toward the center of the electrode. Electrostatic sorting device.