JP2001129435A - Plastic screening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic screening device capable of screening the plastic pieces in recycling in high accuracy in every kind. SOLUTION: A recovering part 12 arranged below a metallic drum electrode 6 is constituted of a recovering vessel 11 for recovering plastic pieces, two separators 13 and 14 arranged in the recovering vessel 11 and movable in the horizontal direction, a control part 18 for controlling the position of these separators 13 and 14, three recovering cambers 15, 16 and 17 formed by being divided by the separators 13 and 14 and measuring instruments 21, 22 and 23 arranged in these recovering chamber 15, 16 and 17 and measuring the weight of the recovered plastic pieces and outputting the measured weight to the control part 18, and also the variation in the mixing ratio of the plastic pieces in operation is detected by the each measuring instrument, and also the each separator is moved to the most suitable place through the control part 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic sorting apparatus for sorting plastic pieces for each type by recycling.

[0002]

2. Description of the Related Art In recent years, while recycling of refuse is being rapidly promoted, there is a plastic sorting apparatus 51 as shown in FIG. 3 as a technique for sorting crushed plastic pieces. The plastic sorting device 51 is disposed below a hopper 53 into which a plurality of types of plastic pieces 52 are charged, and a frictional charging device 54 for charging the plastic pieces 52 to a polarity and a charge amount for each type. An electrostatic separation device 55 is disposed below the device 54 and separates the charged plastic pieces 52 according to the polarity and the charge amount.

The electrostatic separation device 55 includes a metal drum electrode 56 disposed below a chute of the frictional charging device 54, a high voltage electrode 57 disposed obliquely above the metal drum electrode 56, A brush 58 for scraping off the plastic piece 52 attached to the outer peripheral surface of the drum electrode 56; The metal drum electrode 56
Is configured to be rotatable around a horizontal axis in a predetermined direction and is grounded. The high-voltage electrode 57 is connected to, for example, a cathode of a high-voltage power supply 59, and an anode of the high-voltage power supply 59 is grounded. . With this connection, the high voltage electrode 5
A screening electrostatic field 60 is formed between the metal drum electrode 7 and the metal drum electrode 56.

In order to collect the plastic pieces 52 that have passed through the sorting electrostatic field 60 by type, a first separation container 62 and a second separation container 63 separated by a separator 61 are arranged below a metal drum electrode 56. Then it is fixed. The position of the separator 61 is adjusted based on the composition of the plastic piece 52 to be charged so that the recovery purity is optimal.

[0005] In the plastic sorting device 51,
When the plastic piece 52 is put into the hopper 53, the plastic piece 52 is put into the frictional charging device 54 from the hopper 53 and stirred, and the plastic piece 52 is frictionally charged to a predetermined polarity and charge amount according to the type of charging sequence for each plastic piece 52. . After that, the plastic pieces 52 that have dropped into the electrostatic separation device 55 and passed through the sorting electrostatic field 60 are stored in separate containers 62 and 63 for each polarity and charge amount.

[0006]

By the way, as described above, the position of the separator 61 is adjusted so that the purity and the recovery rate are optimized by a preliminary operation test or the like based on the mixing ratio of the plastic pieces 52 to be charged. And was fixed during operation. However, during the actual operation, the mixing ratio of the plastic pieces greatly fluctuates with time due to various environmental changes and the like. It was not possible to cope with fluctuations in the ratio, and thus the purity and recovery rate of the plastic pieces were reduced, so that stable separation performance could not be obtained.

Therefore, an object of the present invention is to provide a plastic sorting apparatus capable of solving the above-mentioned problems.

[0008]

In order to solve the above-mentioned problems, a plastic sorting apparatus of the present invention comprises a friction charging device for stirring and frictionally charging a plurality of types of crushed plastic pieces. An electrostatic separation unit that is disposed below the apparatus and electrostatically separates and separates the charged plastic pieces according to their polarity and charge amount, and a plastic piece that has been separated through the electrostatic separation unit. A collecting unit for separately collecting is provided, and the electrostatic separating unit is arranged via a drum electrode rotatable around a predetermined horizontal axis and a separating space serving as a sorting electrostatic field on the drum electrode. And the polarity of each type by the frictional charging device.
What is claimed is: 1. A plastic sorting apparatus, wherein a plastic piece having a charged amount is separated and collected by passing through the separation space, wherein a plurality of collection chambers are formed in the collection section by partition walls. Is movable in the horizontal direction, and the position of the partition wall is adjusted in accordance with the mixing ratio of a plurality of types of plastic pieces to be fed.

According to the above configuration, a plurality of collection chambers are formed by the plurality of partition walls provided in the collection section, and the partition walls are horizontally arranged based on the mixing ratio of the plurality of types of plastic pieces to be charged. Since it can be adjusted to be movable, it is possible to efficiently separate and collect the plastic pieces at a collection rate corresponding to the mixing ratio of each plastic piece.

According to another aspect of the present invention, in the above-described sorting apparatus, a weighing device for measuring the weight of the collected plastic pieces is installed in each of the collecting chambers, and the weighing device output from the weighing device is provided. A control unit for controlling the position of the partition wall based on the result is provided, and the control unit controls the mixing ratio of the plastic pieces to be input, the position of the partition wall, and the collected plastic corresponding to these. It has a database in which the weight ratio of the pieces is stored, and the position of the partition wall is controlled by referring to the database.

According to the above construction, the control unit for controlling the position of the partition wall is made to input the weighing result from the measuring device for measuring the weight of the plastic pieces collected in each collection chamber. A database storing the mixing ratio of the plastic pieces to be obtained, the position of the partition wall, and the weight ratio of the collected plastic pieces corresponding thereto is provided, so that the mixing ratio of the plastic pieces input during operation is reduced. Even if it fluctuates, it is possible to detect the change in the mixing ratio by the change in the weight of the plastic piece output from the measuring device, and to move each partition wall to the optimum position with reference to the database. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plastic sorting apparatus according to an embodiment of the present invention will be described below with reference to FIGS. The plastic sorting apparatus 1 according to the present invention separates and collects a plurality of different types of resin-based plastic pieces 2 for each type. When the plastic piece 2 is frictionally charged by the friction charging device 3, the plastic piece 2 is charged to either plus or minus according to the charging sequence. For example, PP (polypropylene) and PE (polyethylene) are agitated by the friction charging device 3 as the plastic piece 2. And charge it,
PP is charged to (-), PE is charged to (+), and separated and collected for each type. As PP and PE, for example, those crushed in advance to 5 mm or less are used.

That is, the plastic sorting device 1 of the present invention is arranged below a frictional charging device 3 for frictionally charging in a state where PP and PE are mixed and charged, and a discharge opening 4 which can be freely opened and closed in the frictional charging device 3. A fixed amount supply device 5 for controlling the supply of the plastic piece 2, a metal drum electrode 6 arranged near the lower part of the fixed amount supply device 5, rotatably around a predetermined horizontal axis, and grounded; A high voltage electrode (opposite electrode) 8 is disposed diagonally above the metal drum electrode 6 and is disposed via a separation space 7 serving as a sorting electrostatic field, and a cathode is connected to the high voltage electrode 8. A high-voltage power supply device 9 for applying a voltage to the high-voltage electrode 8 with the positive electrode grounded;
And a brush 10 for scraping off the plastic pieces 2 attached to the metal drum electrode 6 disposed at the lower part of the outer peripheral surface of the metal drum 6. The brush 10 is separated below the separation space 7 by polarity and charge amount under the separation space 7. A collection unit 12 having a collection container 11 for separately collecting the plastic pieces 2.

The collection section 12 includes a first separator (partition wall) 13 disposed on the metal drum electrode side and a second separator (partition) disposed on the high voltage electrode side 8 inside the collection container 11 having a rectangular shape in a plan view. A partition wall) 14 and three recovery chambers formed by being partitioned by the two separators 13, 14, that is, a first recovery chamber 15 disposed below the metal drum electrode 6 and a high voltage electrode 8. A second recovery chamber 16 disposed therein, a third recovery chamber 17 disposed between the first and second recovery chambers, and a control unit 18 for controlling the positions of the first and second separators 13 and 14. It is configured. The first and second separators 13 and 14
A screw mechanism 20 (a ball screw or the like is used), which is guided on both sides by horizontally arranged moving rails (not shown), and is rotated in parallel with the moving rails by a driving device 19 such as a motor. ) Makes it possible to move in the horizontal direction so as to approach and separate from the metal drum electrode 6. In addition, each of the separators 13, 1
4 are independently movable by a driving device 19 based on a signal from the control unit 18. As a means for moving the separator, a cylinder device or the like may be used in addition to the screw mechanism.

A discharge measuring conveyor (weighing device) for discharging the collected plastic pieces 2 and weighing the plastic pieces 2 at predetermined time intervals is provided at a discharge section at the bottom of each of the recovery chambers 15, 16, and 17. 21, 22, and 23 are provided, respectively. Then, the weight of the plastic pieces 2 measured in each collection chamber is output to the control unit 18 every predetermined time, and the weight ratio of each plastic piece 2 collected in the predetermined time is calculated.

The control section 18 has a mixing ratio of the plastic pieces 2 to be charged, positions of the separators 13 and 14 capable of obtaining a predetermined purity at the mixing ratio, and positions of the separators 13 and 14. , A database having a data table storing the weight ratio of the plastic pieces 2 collected in the collection chambers 15, 16, and 17 is provided.

For example, as shown in the following [Table 1], the data table includes a number indicating the position of each separator, a mixing ratio of PP and PE charged, PP collected in each collection chamber, The weight ratio of PE and of the mixture of PP and PE is written. The position of the separator written in the data table is obtained by an experiment, and the purity of each collected plastic piece is set to 99% or more.

[0018]

[Table 1] By referring to this data table, the control unit 18
Then, from the mixing ratio of the plastic pieces 2 given at the start of operation, the weight ratio at which the recovery rate is maximized, that is, the weight ratio of the recovered mixture of PP and PE, which is the lowest, is selected.
The respective separators 13 and 14 are moved to the corresponding positions. During the operation, the control unit 18 checks whether the weight ratio calculated every predetermined time has changed from the initial value, and if there is no change, the operation continues as it is.

However, if the mixing ratio of the injected plastic pieces 2 fluctuates due to various environmental changes or the like that occur during operation, the recovery rate of the plastic pieces 2 decreases. That is, in the example of the above data table, the collected PP and PE
The weight ratio of the mixture increases and the weight ratio of PP and PE decreases. Therefore, when the weight ratio of the output plastic piece 2 changes, the control unit 18 refers to the data table based on the positions and weight ratios of the first and second separators 13 and 14 at that time and refers to the data table. The mixing ratio of the plastic pieces 2 thus determined is controlled, and the positions of the separators 13 and 14 at which the highest recovery rate is obtained at this mixing ratio are controlled.

In the above configuration, the injected plastic piece 2 is charged by the frictional charging device 3, is injected into the fixed amount supply device 5 from the discharge port 4, and is dropped and supplied onto the metal drum electrode 6. When the plastic piece 2 passes between the rotating metal drum electrode 6 and the high-voltage electrode 8, the PE charged to (+) by the frictional charging device 3.
Is attracted to the high-voltage electrode 8 to which the cathode is connected, and is collected in the second collection chamber 16. On the other hand, the (−) charged P
P is attracted to the metal drum electrode 6 and the first collection chamber 1
The PP collected on the metallic drum electrode 6 is scraped off by the brush 10 and collected in the first collecting chamber 15. And, PP and PE with a small charge amount are:
Third collection chamber 17 between first collection chamber 15 and second collection chamber 16
Will be collected.

With respect to the plastic pieces 2 collected in the third collection chamber 17, after the charge is removed, the plastic pieces 2 are again charged into the frictional charging device 3 and frictionally charged, and the above operation is repeated. Thereby, the plastic pieces 2 can be separated and collected for each charge amount. Here, for example, when the mixing ratio of PP and PE given as an initial value is 5: 5, the control unit 18 refers to the data table of [Table 1], and places each separator 13 at a position where the recovery rate is maximum. Move 14 That is, as shown in FIG.
The mixture of E and the recovered weight ratio of PE are moved to a position of / 4: 3: 3.

Then, during operation, for example, PP: (PP
+ PE): When the weight ratio of PE changes to 1.5: 6: 2.5, the control unit 18 refers to the data table in [Table 1] and at this point, the mixing ratio of PP and PE is 2: 8 is detected. In this case, although the mixing ratio of PE increases from 5 to 8, the weight ratio of the recovered PE decreases (3 → 2.5), and the weight ratio of the mixture of PP and PE increases. (4 → 6), the position of the separators 12 and 13 that can obtain the maximum recovery rate in this mixing ratio is found. According to the data table of [Table 1], when the mixing ratio of PP and PE is 2: 8, the weight ratio at which the maximum recovery rate is obtained is 1.5: 4: 4.5, and the position of the corresponding separator is As shown by the phantom line in FIG. 2, the second separator 14 is moved to a position where the weight ratio can be obtained, that is, from.

As described above, according to the embodiment of the present invention, in the control unit 18, the collected plastic pieces 2
The weight ratio is sequentially monitored, and when the weight ratio fluctuates, the positions of the separators 13 and 14 are controlled so as to always obtain the maximum recovery rate by referring to the database. Separation and recovery of the plastic pieces 2 with high purity and high recovery rate can be performed.

In the above embodiment, each of the separators 13 and 14 can be moved in the horizontal direction by the screw mechanism 20, but a lower end of each of the separators 13 and 14 is inserted with a spindle provided with a servomotor. Alternatively, the width of the opening of each collection chamber may be adjusted by swinging the separator around the support shaft by rotating the support shaft with the servo motor.

[0025]

As described above, according to the plastic sorting apparatus of the present invention, a plurality of collecting chambers are formed by a plurality of partition walls provided in the collecting section, and a mixing ratio of a plurality of kinds of plastic pieces to be put in is formed. The partition wall can be adjusted so as to be movable in the horizontal direction based on the above, so that the plastic pieces can be separated and recovered efficiently at a recovery rate corresponding to the mixing ratio of each plastic piece.

Further, the control section for controlling the position of the partition wall is inputted with the weighing result from the measuring device for measuring the weight of the plastic pieces collected in each collection chamber. A database storing the mixing ratio of the pieces, the position of the partition wall, and the weight ratio of the collected plastic pieces corresponding thereto is provided, so that the mixing ratio of the plastic pieces input during operation fluctuates. Even when the change in the mixing ratio is detected based on the change in the weight of the plastic piece output from the measuring device, the database is referred to and the partition wall is moved to the optimum position, so that a high recovery rate is always obtained. Separation and recovery can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a plastic sorting device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of a recovery unit according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a schematic configuration of a conventional plastic sorting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic sorting device 2 Plastic piece 3 Friction charging device 6 Metal drum electrode 7 Electrostatic separation space 8 High voltage electrode 12 Recovery part 13, 14 Separator 18 Control part 21-23 Discharge weighing conveyor

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuyoshi Kato 1-7-89 Minami Kohoku, Suminoe-ku, Osaka-shi, Osaka F-term in Hitachi Zosen Corporation 4D054 GA04 GA09 GB01 GB08 4F301 AA00 AD10 BA12 BA15 BA21 BF03 BF12 BF40

Claims (3)

[Claims] 1. A friction charging device for stirring and frictionally charging a plurality of types of crushed plastic pieces, and a charged plastic piece disposed below the friction charging device according to its polarity and charge amount. An electrostatic separation unit for electrostatic separation and sorting, and a collection unit for separately collecting plastic pieces that have passed and separated by the electrostatic separation unit are provided, and the electrostatic separation unit is A drum electrode rotatable about a predetermined horizontal axis, and a counter electrode disposed on the drum electrode via a separation space serving as a sorting electrostatic field. A plastic sorting device that is configured to pass through the separation space to separate and collect the plastic pieces, and the collection unit includes a plurality of collection chambers formed by partition walls.
A plastic sorting apparatus wherein the partition wall is movable in a horizontal direction, and the position of the partition wall is adjusted according to a mixing ratio of a plurality of types of plastic pieces to be supplied. 2. A weighing device for measuring the weight of the collected plastic pieces is provided in each of the collecting chambers, and a control unit for controlling the position of the partition wall based on the weighing result output from the weighing device is provided. The plastic sorting apparatus according to claim 1, wherein 3. The control unit has a database in which the mixing ratio of the plastic pieces to be charged, the position of the partition wall, and the weight ratio of the collected plastic pieces corresponding to these are stored in the control unit, and this database is referred to. 3. The plastic sorting apparatus according to claim 2, wherein the position of the partition wall is controlled by this.