JPH1024251A - Triboelectrifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively electrify plastic fragments to be classified before feeding them into an electrostatic selector to separate them according to their kinds by the electrostatic selector and improve selection accuracy. SOLUTION: A triboelectrifying device is equipped with a cylindrical electrifying vessel 3 made of a resin material to be subjected to friction in which a feeding port 3a for plastic fragments is formed at one end and also a discharge port 3b for plastic fragments is formed at the other end, and an agitating and slidably contacting device 8 in which agitating blades (agitating brushes) 7 made of a resin material to be subjected to friction are fitted to a vertical rotating shaft 5 rotated by an agitating drive motor 6 in the electrifying vessel 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a triboelectric charging device used for pretreatment of an electrostatic sorter for separating crushed plastic pieces or the like for recycling by type.

[0002]

2. Description of the Related Art For example, plastics currently consumed as products and materials include vinyl chloride resins (hereinafter referred to as PV).
C), polyethylene-based resin (hereinafter abbreviated as PE), polypropylene-based resin (hereinafter abbreviated as PP), polystyrene-based resin (hereinafter abbreviated as PS), and methacrylic resin [acrylic resin] (hereinafter abbreviated as PMMA). Is considered to account for about 80% of the total, and the waste plastics recovered are considered to be mostly occupied by the resins. In addition, polyethylene terephthalate resin (hereinafter abbreviated as PET), which is frequently used as a PET bottle, is being independently collected. When recycling these resins, it is important to separate them for each resin, but no separation technology has been established.

Conventionally, there is, for example, an electrostatic sorter for sorting crushed waste. This electrostatic sorter includes a grounded drum electrode and a fixed electrode to which a high voltage is applied, and is formed of a drum electrode and a fixed electrode by putting an object to be sorted on a rotating drum electrode. The insulator separates into an insulator that passes through the electrostatic field and is strongly charged and strongly attracted to the drum electrode side, a conductor that is not charged and repels the drum electrode, and a semiconductor in between.

[0004]

By the way, when plastics, which are insulators, are separated by type using an electrostatic separation device, those which are easily (positively) charged and those which are negatively (negative) depending on the position of the charging line. However, when using the above-mentioned electrostatic separator to separate plastic pieces by material, in the electrostatic field formed by the drum electrode and the fixed electrode, the charge amount (pressure) of each plastic piece is used. ) Is a very slight difference, and it is difficult to sort using this difference.

According to the first aspect of the present invention, it is possible to more effectively charge a plastic piece, to separate each type of plastic piece in an electrostatic separator, and to further improve the separation accuracy. An object of the present invention is to provide a triboelectric charging device.

[0006]

According to the first aspect of the present invention, there is provided a triboelectric charging apparatus for pre-treating a plastic piece before supplying the plastic piece to an electrostatic sorting apparatus. A cylindrical charging container having a plastic piece input port formed at one end and a plastic piece discharge port formed at the other end and at least an inner surface covered with a friction-resistant resin material; and an axial center in the charging container. Stirrer having a stirring member attached to a rotating shaft rotatably arranged in the section and rotated by a stirring driving device, wherein the stirring member has a stirring blade having at least a contact surface covered with a frictional resin material or It is constituted by a stirring brush.

According to the first aspect of the present invention, the plastic piece supplied into the charging container is brought into contact with the inner surface of the charging container and the resin material to be rubbed of the stirring member while being agitated and rotated by the agitating sliding contact means. By doing so, it is possible to effectively contact and charge for a long time, thereby improving the sorting accuracy in the electrostatic sorter. Further, since the inner surface of the charging container and the surface of the stirring member to be contacted are covered with the resin which is an insulator, the charged electric charge does not escape.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, first to fourth embodiments of the frictional charging device according to the present invention will be described with reference to FIGS.

First, FIGS. 1 and 2 show a first embodiment. Reference numeral 2 denotes a frictional charging device according to the present invention for pre-treating a plastic piece before being supplied to the electrostatic sorting device 1. The friction charging device is formed of plastic, which is a resin material to be rubbed, and has a plastic piece input port 3a formed at the upper end. In addition, a vertical cylindrical charging container 3 having a plastic piece discharge port 3b formed at the lower end is disposed, and a plastic piece supply device 4 for supplying a predetermined amount of plastic pieces to the charging container 3 is provided. The plastic piece supply device 4 includes a supply hopper 4a for storing plastic pieces, a screw feeder 4b for cutting out a fixed amount of plastic pieces, and an adjustment valve 4c, and is connected to the charging port 3a of the charging container 3.

The agitating and sliding device 8 provided on the charging container 4 includes a vertical rotation shaft 5 rotatably supported via a bearing at an axis of the charging container 8, and a rotating shaft 5. Stirring drive motor 6 which is a stirring drive with an output shaft connected
For example, 45% over the entire length around the vertical rotation shaft 5.
And a strip-shaped stirring blade 7 which is a stirring member attached in the radial direction at each angle. In addition, this stirring blade 7
And the charging container 3 are made of the same type and made of a frictional resin material at an intermediate position of the charging line. The stirring blade is made of the same soft resin, and its width is set to 10 mm, for example, when one side of the plastic piece is 10 mm or less, and the width may be increased as the size of the plastic side increases.

In other words, a plastic material, which is an insulating material, is used as the resin material to be rubbed in order to prevent the electric charges charged in the plastic pieces from escaping. In addition, PVC with a large amount of recovery,
When PE, PP, PS, PMMA and PET are arranged in the charging column order, PMMA → P
S → PE → PP → PET → PVC (PP → PVC → PE
T is also available) and arranged on the side that is more likely to be negatively charged. Here, PS, P located in the middle order
For example, when PP is selected as a frictional resin material from E and PP, and the frictional resin material made of PP is rubbed against another plastic piece, a large amount of positive charges increase in the order of PE <PS <PMMA plastic pieces. It is charged, and PP plastic pieces are hardly charged. Further, a large number of negative charges are charged in the order of plastic pieces of PET <PVC. In this way, by selecting the plastic in the middle rank of the charging line as the reference plastic material, the mixed plastic pieces are charged with positive and negative charges for each type, and the charge amount (band) is determined for each type. Voltage).

The charging container 3 and the stirring blade 7 may be coated with a resin material to be rubbed on the surface of a metal material which guarantees strength and flexibility.

In the above configuration, the plastic piece supplied into the charging container 3 from the plastic piece supply device 4 of the frictional charging device 2 through the charging port 3a is moved by the stirring drive motor 6
As a result, the mixing and stirring are performed by the stirring blade 7 rotated through the vertical rotation shaft 5, and the plastic pieces inside and the stirring blade and the inner surface of the charging container 3 are frictionally slid into contact with each other, so that a positive or negative charge is charged. The plastic piece discharged from the discharge port 3b and sent to the electrostatic separation device 1 is formed between the rotating drum electrode 1b to which a high voltage is applied from the power supply device 1c and the electrode rod 1d from the vibration conveyor 1a. The plastic piece charged into the sorting electrostatic field S and charged with a negative charge is the rotating drum electrode 1 on the positive electrode side.
b, is separated into the first tray 1e, and the positively charged plastic piece is a rotating drum electrode 1
The same plastic piece as the reference plastic material that has been repelled by b and is separated into the third tray 1g and is not charged is dropped as it is and separated into the second tray 1f.

According to the first embodiment, before being put into the electrostatic separator 1, the frictional charging device 2 causes the frictional contact between the resin-made resin material and the plastic pieces to make contact.
Effective charging in a short period of time, enabling the sorting of each type of plastic piece in the electrostatic sorter 1 in the subsequent process,
Further, the accuracy of sorting can be greatly improved.

Next, a second embodiment will be described with reference to FIGS. The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the second embodiment, the stirring member is replaced with the stirring blade 7 and a stirring brush 8 made of a frictional resin material is employed. This stirring brush is obtained by collecting wires having a diameter of about 1 mm and implanting them on the vertical rotation shaft 5 in the radial direction at every 45 °, for example. According to the second embodiment, the same effects as those of the first embodiment can be obtained.

Further, a third embodiment will be described with reference to FIGS. The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In this frictional charging device, a charging container 13 is disposed horizontally, and a strip-shaped stirring blade 17 is spirally mounted on a horizontal rotating shaft 15 to generate a feeding effect of a plastic piece. This third
This embodiment can also provide the same effects as the first embodiment.

A fourth embodiment will be described with reference to FIGS. In the fourth embodiment, the stirring blade 17 of the third embodiment is replaced with a stirring brush 19, and a conveying force of a plastic piece is applied to a stirring brush 28 spirally implanted on the horizontal rotating shaft 15. It is what you have. This third embodiment can also provide the same effects as the first embodiment.

[0018]

As described above, according to the first aspect of the present invention, the plastic pieces supplied into the charging container are agitated and rotated by the agitating means, and the plastic pieces are formed on the inner surface of the charging container and the frictional resin material of the agitating member. By contacting and rubbing, it can be effectively slid and charged for a long time,
It is possible to separate each type of plastic pieces in the electrostatic sorter, and it is possible to improve the sorting accuracy. Further, since the inner surface of the charging container and the surface of the stirring member to be contacted are covered with the resin which is an insulator, the charged electric charge does not escape.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a frictional charging device according to the present invention.

FIG. 2 is a plan sectional view of the charging container.

FIG. 3 is a configuration diagram illustrating a friction charging device according to a second embodiment of the present invention.

FIG. 4 is a perspective view showing a stirring blade of the charging container.

FIG. 5 is a configuration diagram showing a third embodiment of the frictional charging device according to the present invention.

FIG. 6 is a perspective view showing a stirring blade of the charging container.

FIG. 7 is a configuration diagram illustrating a friction charging device according to a fourth embodiment of the present invention.

FIG. 8 is a plan sectional view of the charging container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrostatic sorting device 2 Friction charging device 3, 13 Charging container 3a Input port 3b Discharge port 4 Plastic piece supply device 5 Vertical rotation shaft 6 Stirring drive motor 7.17 Stirring blade 8 Stirring sliding contact device 9, 19 Stirring brush 15 Horizontal Axis of rotation

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hidehiko Maehata 5-3-28 Nishikujo, Konohana-ku, Osaka City, Osaka Inside Hitachi Zosen Corporation

Claims (1)

[Claims] 1. A friction charging device for pre-treating a plastic piece before feeding it to an electrostatic sorting device, wherein a plastic piece input port is formed at one end and a plastic piece discharge port is provided at the other end. A cylindrical charging container having at least an inner surface covered with a frictional resin material, and a stirring member attached to a rotating shaft rotatably disposed at an axial center of the charging container and rotated by a stirring driving device. A friction stir contact device, wherein the stirring member is constituted by a stirring blade or a stirring brush having at least a contact surface covered with a frictional resin material.