JPH09977A - Electrostatic selector - Google Patents

Abstract

PURPOSE: To improve the classifying accuracy by strong attraction force and to prevent the flying of a material to be classified caused by an ionic wind. CONSTITUTION: An electrode forming an electric field between it and a conductive rotor is integrally constituted of a planar electrode part 22A forming an electrostatic area D1 and an acicular electrode part 22B forming a corona discharge area D2. In this way, an ionic wind to the upstream side is eliminated by the planar electrode part, and strong attraction force is given to insulating crushed refuse by the acicular electrode part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crushed waste having a mixture of an insulating material and a conductive material, which has a relatively large particle size, such as a plastic or a combustible material for recycling from the crushed waste. The present invention relates to an electrostatic separation device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 6 and 7, an electrostatic separator for separating insulating particles and conductive particles has been rotated in a predetermined direction around the horizontal axis to, for example, a negative ground (earth). Mixed particles are cut out from the hopper 2 through the quantitative vibration feeder 3 on the upper surface of the electrically conductive rotor 1 thus formed, and an electric field D is generated between the rotor 5 and the electrode 5A or 5B to which a high voltage is applied by the power source 4. It is formed. When the mixed particles enter the electric field D, the mixed particles receive an electric charge, and the insulating particles do not have a charge replenishment from the ground electrode. Adsorbed. Further, the conductive particles are separated from each other because the electric charge received from the electric field D is neutralized with the opposite electric charge from the rotor 1 and further the electric charge is always applied from the rotor 1, so that the conductive particles are repulsive to the rotor 1.

In this way, the conductive particles are separated and fall into the sorting tray 6A arranged on the upstream side in the rotation direction of the rotor 1, and the semiconductive particles are dropped into the intermediate sorting tray 6B. The scraper 7 separates the insulating particles scraped from the surface of the rotor 1 by the scraper 7 on the sorting tray 6C at the rearmost portion.

By the way, as shown in FIG. 6, the electrostatic sorting device uses an electrostatic induction type in which an electrostatic area D is formed between the electrode 5A and the rotor 1 by using a flat (roll-shaped) electrode. Then, as shown in FIG. 7, there is a corona discharge type in which a corona discharge region D is formed between the electrode 5B and the rotor 1 by using a needle electrode.

[0005]

However, the electrostatic induction type has a problem that the mixed particles easily fall when passing through the electrostatic region D and have a weak adsorption force. Further, the corona discharge type has a problem that the mixed particles fly up due to the ionic wind generated by the unequal electric field, and the sorting accuracy is lowered.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide an electrostatic separation device which has a strong adsorption force and which does not deteriorate the separation accuracy due to the scattering of the object to be sorted by the ion wind. To do.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a conductive rotor rotatable about a horizontal axis, a hopper for feeding an object to be sorted onto the conductive rotor, and a conductive rotor. An electrode arranged on the inlet side of the object to be sorted of the rotor, a power source for applying a high voltage between the electrode and the conductive rotor to form an electric field, and below the conductive rotor along the rotating direction of the conductive rotor. And a sorting tray having a plurality of sorting trays arranged thereon, the flat electrode section for forming the electrostatic region between the electrode and the conductive rotor, the electrode being arranged on the upstream side in the feeding direction of the object to be sorted. And a needle-shaped electrode portion, which is arranged on the downstream side of the object to be separated in the feed direction and forms a corona discharge region with the conductive rotor, are integrally formed.

Further, the flat electrode portion of the above-mentioned electrode is formed in an arc surface parallel to the outer peripheral surface of the conductive rotor. Further, at least one of the conductive rotor and the needle-shaped electrode portion having the above-mentioned configuration is coated with an insulating material.

[0009]

According to each of the above constructions, the object to be sorted first passes through the electrostatic region and then passes through the corona discharge region.
The insulating material to be sorted has a strong adsorption force, and the semi-conductive material to be sorted has a certain amount of adsorption force, and the flat electrode portion arranged on the upstream side allows the ions to flow from the needle electrode to the upstream side. Since the wind is prevented and the objects to be sorted are prevented from scattering, the sorting accuracy is further improved. Further, the ion wind flowing downstream from the needle-shaped electrode blows off the insulator having a weak adsorption force and separates it, so that more effective separation can be performed. Further, since the flat electrode portion and the needle electrode portion are integrated, the electrode can be made compact.

Further, by forming the flat electrode portion in the shape of an arc surface, a more uniform electric field can be obtained and the generation of ion wind can be reliably prevented. Furthermore, by coating with an insulating material, it is possible to prevent sparks from being picked up to the object to be sorted that contains water and the like, and to prevent charging stoppage due to voltage drop after sparking.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the electrostatic sorting apparatus for crushed dust according to the present invention will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 1, a conductive rotor 11 is installed which is rotated around a horizontal axis in the direction of arrow A by a rotary drive device (not shown).
Is negatively grounded via the lead wire 12. In addition, above the conductive rotor 11, a hopper 13 that supplies the crushed waste E, which is an example of an object to be sorted, is arranged,
Conductive rotor 11 via vibrating feeder 14 for constant quantity supply
It is configured such that the crushed waste E is supplied to the upper portion by a predetermined amount. Further, above the conveying plate 14a of the vibrating feeder 14,
An unraveling device 15 for unraveling the crushed dust by relatively reciprocating a plurality of rows of comb teeth in a transverse direction is provided.

The electrode 16 is provided at a predetermined distance above the top of the conductive rotor 11 and slightly downstream in the direction of rotation A.
Is arranged and the positive electrode of the discharge field forming power supply 17 is connected to the electrode 16 to form electric fields (regions) D1 and D2 between the electrode 16 and the conductive rotor 11.
In addition, a conductive waste receiving tray 18, a semi-conductive waste receiving tray 19, and an insulating dust receiving tray 20 are arranged below the conductive rotor 11 in the rotation direction A from the upstream side to the downstream side. A scraping brush 21 which is an example of scraping means for forcibly separating the insulative dust adsorbed by slidingly contacting the conductive rotor 11 is provided above 20.

As shown in FIG. 2, the electrode 16 has a flat plate electrode 22a on the upstream side in the rotational direction A and forms a static area D1 between the flat plate electrode 22a and the conductive rotor 11.
2A and a needle-shaped electrode portion 22B that is arranged in a row in the width direction on the downstream side in the rotation direction A and that forms a corona discharge region D2 between the conductive rotor 11 and the needle-shaped electrode portion 22B. The needle-shaped electrode portion 22B includes a shaft portion 22b protruding from the downstream edge of the flat plate electrode 22a at regular intervals in the width direction, and the shaft portion 22b.
The tip end side of b is formed of a needle electrode 22c that is bent toward the conductive rotor 11 side and is formed in a pointed shape, and the flat electrode portion 22A and the needle electrode portion 22B are integrally molded to form the flat electrode portion 22A side. A lead wire 23 for applying a voltage from a power source 17 is connected to the.

The needle electrodes 22c are coated with an insulating material 24 such as an acrylic material to prevent spark (spark discharge) due to water contained in the crushed dust E. When this spark occurs, its sparks shatter trash E
There is a risk of igniting the combustible substance of No. 2 and causing a fire, and it takes several tens to several hundreds of milliseconds to return to the original voltage even if the voltage drops at the moment of sparking. The crushed dust E passing through D2 is not charged and the sorting accuracy is reduced.

Further, the distance L between the needle-shaped electrode portion 22B and the conductive rotor 11 is set to the voltage Vp so that the following condition is satisfied.
Is set. L (mm)> Vp (kV) /0.5 (kV / mm)

In the above embodiment, the crushed dust E supplied from the hopper 13 to the vibrating feeder 14 is sent along the inclination of the conveying plate 14a of the vibrating feeder 14, and
Conductive crushed waste Ea, semi-conductive crushed waste Eb and insulating crushed waste Ec entwined with each other by the loosening device 15.
Is separated and loosened. Then, the pulverized dust E is charged onto the conductive rotor 11 and conveyed along the rotation direction A, and the pulverized dust E is supplied with an electric charge for each particle in the electrostatic region D1 formed by the flat electrode portion 22A of the electrode 16. . Further, the corona discharge region D formed by the needle electrode portion 22B
2, the crushed waste E passes through the ion shower or the electron shower and receives electron emission. As a result, since the insulating crushed dust Ec such as plastics is not replenished with electric charge from the conductive rotor 11, the electric charge given by the electron emission exerts an attractive force on the conductive rotor 11 and further an attractive force for polarization. It is integrated and strongly adsorbed. Further, the conductive ground dust Ea such as metals is transferred to the conductive rotor 11 because the charge due to corona discharge is neutralized with the opposite charge from the conductive rotor 11, and the opposite charge is always given from the conductive rotor 11. It becomes the repulsive force of and is separated.
Further, even if it is treated by a dryer, the intermediate semi-conductive crushed dust Eb such as wood and paper containing several% of water is adsorbed to the electro-conductive rotor 11 with a certain adsorbing force.

Then, the conductive crushed dust Ea repelled by the conductive rotor 11 is dropped and discharged to the first conductive dust receiving tray 18, and the semi-conductive crushed dust Eb is absorbed by the conductive rotor 11 to some extent. In the lower part of the conductive rotor 11, the insulating crushed dust Ec, which is dropped and discharged to the next semi-conductive dust receiving tray 19 by its own weight and further strongly attracted to the conductive rotor 11, is insulated by its own weight and the scraping brush 21. It is dropped and discharged to the sex dust receiving tray 20.

According to the above embodiment, the crushed dust E first passes through the electrostatic region D1 and then passes through the corona discharge region D2, whereby the insulating crushed dust Ea obtains a strong adsorption force.
Since the semiconductive crushed dust Eb can obtain a proper suction force, the sorting accuracy is further improved. Then, due to the electrostatic field D1 which is a uniform electric field formed by the flat electrode portion 22A on the upstream side, the ion wind generated in the corona discharge area D2 which is a non-uniform electric field is generated only on the downstream side in the rotation direction A. Therefore, the pulverized dust E does not rise to the upstream side due to the ionic wind, and the conductive static pulverized dust Ea having a weak adsorption force is reliably separated downward due to the ionic wind on the downstream side, so that the separation effect is further improved. You can Further, since the flat electrode portion 22A and the needle electrode portion 22B are integrated, the electrode 16 can be made compact.

Since the needle electrode 22c of the needle-shaped electrode portion 22B is coated with the insulating material 24, the crushed dust E
Sparks are prevented even if the metal contains water or water.
This is as shown in FIG.
On the c side, electric charges opposite to the needle electrode 22c are collected, and the insulating material 2
The same charge as that of the needle electrode 22c is collected on the surface side of 4 to form the corona discharge region D2 in the same manner as when there is no insulating material 24, so that the function as an electrode is not impaired. This is because a large current does not flow between the needle electrode 22c and the conductive rotor 11 and no spark is generated. As a result, it is possible to prevent the charging from being stopped and the fire from occurring due to the instantaneous voltage drop. The conductive rotor 11 may be coated with the insulating material 25, or both may be coated with the insulating materials 24 and 25.

The flat plate electrode 22a in the above embodiment
As shown in FIG. 4, the arc-shaped surface electrode 22a ′ allows the distance L from the outer peripheral surface of the conductive rotor 11 to be constant over the entire surface, and a uniform electrostatic area D1 can be obtained.
The generation of ionic wind can be reliably prevented.

When the electrostatic separation force of the electrostatic induction of the electrostatic region D1 is not so strong, as shown in FIG.
A needle electrode in which a plurality of shaft electrode portions 32b are extended in parallel from the power feeding member 32a to form a planar electrode portion 32A, and a tip end portion of the shaft portion 32b is bent toward the conductive rotor 11 side and coated with an insulating material 33. With 32c,
It is also possible to configure the needle electrode portion 32B.

[0023]

As described above, according to the present invention, the object to be sorted first passes through the electrostatic region and then the corona discharge region, so that the insulating object to be sorted obtains a strong adsorption force. The semi-conductive material to be sorted can obtain a certain amount of adsorption force, and the flat electrode section located on the upstream side prevents the ion wind from the needle-shaped electrode to the upstream side, preventing scattering of the material to be sorted. Therefore, the sorting accuracy is further improved. Further, the ion wind flowing downstream from the needle-shaped electrode blows off the insulator having a weak adsorption force to separate the insulator, so that more effective separation can be performed. Furthermore, since the flat electrode portion and the needle electrode portion are integrated, the electrode can be made compact.

Further, by forming the flat electrode portion in the shape of an arc surface, a more uniform electric field can be obtained and the generation of ion wind can be reliably prevented. Furthermore, by coating with an insulating material, it is possible to prevent sparks from being picked up to the object to be sorted that contains water and the like, and to prevent charging stoppage due to voltage drop after sparking.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an electrostatic sorting device for crushed dust according to the present invention.

FIG. 2 is a perspective view showing electrodes of the electrostatic sorting apparatus.

FIG. 3 is a partially enlarged view illustrating an electrode of the electrostatic sorting device.

FIG. 4 is a perspective view showing another embodiment of the electrodes of the electrostatic sorting device.

FIG. 5 is a perspective view showing another embodiment of the electrodes of the electrostatic sorting apparatus.

FIG. 6 is a schematic configuration diagram showing a conventional electrostatic induction type electrostatic sorting device.

FIG. 7 is a schematic configuration diagram showing a conventional corona discharge type electrostatic sorting device.

[Explanation of symbols]

 D1 electrostatic area D2 corona discharge area E crushed dust 11 conductive rotor 16 electrode 17 power supply 18 conductive dust receiving tray 19 semi-conductive dust receiving tray 20 insulating dust receiving tray 22A flat electrode portion 22B needle electrode portion 22a flat plate electrode 22a 'Arc surface electrode 22b Shaft part 22c Needle electrode 24 Insulating material 25 Insulating material 34 Unraveling drive device 41 Unraveling device 43 Sieve plate 44 Unraveling drive device

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Hiroyuki Carpenter, 3-8, Nishikujo 5-chome, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. (72) Hidehiko Maebata 5-chome, Nishikujo, Konohana-ku, Osaka City, Osaka 3-28 Hitachi Shipbuilding Co., Ltd. (72) Inventor Chiaki Tojo 5-3-28 Nishikujo, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd.

Claims (3)

[Claims] 1. A conductive rotor which is rotatable around a horizontal axis, a hopper for feeding an object to be sorted onto this conductive rotor, an electrode arranged on the object inlet side of the conductive rotor, and this electrode. And a conductive rotor, a power source for applying a high voltage to form an electric field, and a plurality of sorting trays arranged below the conductive rotor along the rotation direction of the conductive rotor. In the above, the electrode, a flat electrode portion disposed on the upstream side in the feed direction of the object to be separated to form an electrostatic region between the electrode and the conductive rotor,
An electrostatic sorting device, characterized in that a needle-shaped electrode portion that is disposed on the downstream side of the object to be separated in the feeding direction and forms a corona discharge region is integrally formed with a conductive rotor. 2. The electrostatic sorting apparatus according to claim 1, wherein the flat electrode portion of the electrode is formed in an arc surface parallel to the outer peripheral surface of the conductive rotor. 3. The electrostatic sorting apparatus according to claim 1, wherein at least one of the conductive rotor and the needle-shaped electrode portion is coated with an insulating material.