WO2008075470A1

WO2008075470A1 - Electrostatic sorting apparatus and method of electrostatic sorting

Info

Publication number: WO2008075470A1
Application number: PCT/JP2007/059750
Authority: WO
Inventors: Yasuhiro Endo; Mitsuie Matsumura; Muneaki Mukuda; Akito Tanaka
Original assignee: Mitsubishi Electric Corporation
Priority date: 2006-12-21
Filing date: 2007-05-11
Publication date: 2008-06-26
Also published as: JPWO2008075470A1; JP4889745B2; CN101511487A; CN101511487B

Abstract

An electrostatic sorting apparatus characterized by including earth electrode (1) disposed on one side of the falling path of sorting object; high-voltage application electrode (2) disposed on the other side of the falling path so as to be opposite to the earth electrode (1); first air current generating means for generating an air current in a direction imparting a drag to gravity to either an electrostatic field occurring between the earth electrode (1) and the high-voltage application electrode (2) or separation space (77) provided inferior to the earth electrode (1) and the high-voltage application electrode (2), or both thereof; and second air current generating means for generating an air current against the electrostatic field occurring between the earth electrode (1) and the high-voltage application electrode (2) in parallel to the electrostatic field.

Description

Electrostatic sorting apparatus and electrostatic sorting method

Technical field

TECHNICAL FIELD [0001] The present invention relates to an electrostatic sorting device, and more particularly to an electrostatic sorting device and an electrostatic sorting method for sorting an object using an air stream.

Background art

[0002] As a general electrostatic sorting device, a mixture having a material force with a different frictional charge order was charged by friction between the positive electrode and the negative electrode, and a charged mixture was generated between the electrodes. There is an electrostatic sorting device that sorts using the difference in electrostatic force by passing through the electrostatic field.

[0003] Further, as a sorting device capable of sorting with higher accuracy than a general electrostatic sorting device, an inclined vibrating electrode and an electrostatic electrode disposed above the vibrating electrode via a separation space are provided. In addition, a high voltage is applied between the two electrodes to make the separation space an electrostatic field, and the vibrating electrode is vibrated so as to convey plastic particles in a direction other than the tilting direction, thereby having the same polarity as the vibrating electrode. The charged plastic particles are moved downward in the tilt direction. On the other hand, there are also known vibration-transporting electrostatic separators that move plastic particles charged in the opposite polarity to the vibrating electrode in the conveying direction of the vibrating electrode, and sort the plastic according to the charging characteristics. (For example, see Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-346434 (page 2, lines 2 to 17, FIG. 5)

Disclosure of the invention

[0005] In the conventional electrostatic sorting device described in Patent Document 1, it is necessary to provide a vibration generating source in addition to an electrode for generating an electrostatic field and a high-voltage power source. Since the high voltage is vibrated while being applied to the electrodes, the configuration of the apparatus becomes complicated and expensive, and it is difficult to increase the size, so there is a possibility that it cannot be applied to a recycling plant that requires a large amount of processing. In addition, since the mixture to be sorted does not actually have a uniform mixing ratio, particle size, and particle shape, the charge amount of the particles varies and is biased, resulting in an increase in the sorting accuracy of the electrostatic sorting device. May decrease. [0006] The present invention has been made to solve such a problem, and an object thereof is to provide a stable and highly accurate electrostatic sorting apparatus at low cost.

[0007] In order to solve the above-described problems, an electrostatic sorting apparatus according to the present invention includes a first electrode disposed on one side of a dropping path of an object to be sorted and a first electrode on the other side of the dropping path. A second electrode disposed opposite to the first electrode, an electrostatic field generated between the first electrode and the second electrode, and a separation space below the first electrode and the second electrode. And a first airflow generating means for generating an airflow in a direction to provide resistance against gravity against one or both of them.

[0008] The present invention relates to one or both of the electrostatic field generated between the first electrode and the second electrode and the separation space below the first electrode and the second electrode. In addition, since the first air flow generating means for generating the air flow in the direction of applying the resistance to gravity is provided, it is possible to provide a stable and highly accurate sorting device at a low cost.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

Brief Description of Drawings

FIG. 1 is a schematic configuration diagram of an electrostatic sorting device according to Embodiment 1 of the present invention.

FIG. 2 is a schematic configuration diagram of an electrostatic sorting device according to Embodiment 2 of the present invention.

FIG. 3 is a schematic diagram of the configuration of a conventional electrostatic sorting apparatus.

FIG. 4 is a schematic configuration diagram of an electrostatic sorting device according to Embodiment 3 of the present invention.

FIG. 5 is a schematic configuration diagram of an electrostatic sorting device according to Embodiment 4 of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an electrostatic sorting device according to Embodiment 1 of the present invention. As shown in Fig. 1, the ground electrode 1 (first electrode) and the high-voltage application electrode 2 (second electrode) with a width of 50 cm are placed facing each other at an interval of 50 cm. It becomes a falling path! Further, an air supply / exhaust device 7 is installed above both electrodes, and a + charged particle collection container 61 and a −charged particle collection container 62 are arranged below both electrodes. High voltage application electrode 2 A high-voltage power supply 5 is connected to and a voltage of 40 kV is applied, and an electrostatic field is generated between both electrodes. The first electrode and the second electrode may be misaligned between the ground electrode 1 and the high-voltage applied electrode 2! /.

[0013] At this time, if the mixture having chargeable particle force is charged by stirring or the like and passed through the electrostatic field, the chargeable particle force until reaching the charged particle collection container 61 or the charged particle collection container 62. The positively charged particles are attracted to the installation electrode 1 side, and the uniformly charged particles are attracted to the high voltage application electrode 2 side. As a result, the mixture of charged particles is sorted into positively charged particles and uniformly charged particles.

[0014] For example, in the case of a + charged particle 31 having a specific gravity of 1, a particle diameter of 3 mm, and a charge of +1. OnC, there is no air flow in the electrostatic field, and the conventional general electrostatic sorting in which the particle falls freely In the device, the horizontal movement distance by which the particles are attracted to the ground electrode 1 side by electrostatic force before reaching the collection container is about 7.5 cm. On the other hand, in the electrostatic sorting device according to the first embodiment of the present invention, air is supplied in a direction to provide gravity resistance against the electrostatic field by using the air supply / exhaust device 7 disposed above the electrodes. Stream 41 is generated. For example, if the flow velocity of the air flow 41 is 7.5 m / s, the acceleration of the particle drop is about 1Z 2 at the time of free fall, and the time during which the particle is subjected to electrostatic force becomes longer. As a result, the horizontal movement distance by which the particles are attracted to the ground electrode 1 side by electrostatic force before reaching the collection container is about 15 cm, and the sorting accuracy is improved. In addition, the voltage required to obtain a 7.5 cm travel distance similar to that of the conventional sorting device can be reduced to about 1Z 2 compared to the conventional sorting device.

[0015] For these reasons, the time for the sorting object to pass through the electrostatic field is extended as compared with the conventional case, so that the sorting accuracy is improved. In addition, the voltage required to obtain the same sorting accuracy as before can be reduced.

Note that the same effect can be obtained by using a nitrogen gas or other gas air flow instead of the force air flow 41 using the air flow 41 in the first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an electrostatic sorting device according to Embodiment 2 of the present invention. Embodiment 2 of the present invention is characterized in that the distance between the electrode and the collection container is longer than that of Embodiment 1. The

[0018] As shown in FIG. 2, the ground electrode 1 (first electrode) and the high-voltage application electrode 2 (second electrode) having a width of 8 cm are disposed at an interval of 30 cm. It is a fall path for sorting objects. In addition, an air supply / exhaust device 7 is installed above both electrodes, and a + charged particle collection container 61 and a -charged particle collection container 62 are arranged at a position separating a separation space 77 of 60 cm downward from both electrodes. Speak. A high voltage power source 5 is connected to the high voltage application electrode 2 and a voltage of 30 kV is applied, and an electrostatic field is generated between the two electrodes. Note that the first electrode and the second electrode may be either the ground electrode 1 or the high voltage application electrode 2.

At this time, if the mixture having chargeable particle force is charged by stirring or the like and passed through the electrostatic field, the chargeable particle force until reaching the charged particle collection container 61 or the charged particle collection container 62. The positively charged particles are attracted to the installation electrode 1 side, and the uniformly charged particles are attracted to the high voltage application electrode 2 side. As a result, the mixture of charged particles is sorted into positively charged particles and uniformly charged particles. The separation space 77 is a space provided between the + charged particle collection container 61 and the −charged particle collection container 62 disposed below the ground electrode 1 and the high voltage application electrode 2. No electrostatic force is generated in the separation space 77, but the distance between the separation of the particles can be increased by continuing the horizontal movement of the particles between the electrodes during the fall of the particles. .

[0020] For example, in the case of a + charged particle 31 having a specific gravity of 1, a particle diameter of 3 mm, and a charge of +1. OnC, there is no air flow in the electrostatic field, and the conventional general electrostatic sorting in which the particle falls freely In the device, the horizontal movement distance by which the particles are attracted to the ground electrode 1 side by electrostatic force before reaching the collection container is about 15 cm. On the other hand, in the electrostatic sorting device according to Embodiment 2 of the present invention, the direction of giving an anti-gravity force to the electrostatic field and the separation space 77 by using the air supply / exhaust device 7 arranged above the electrodes. Air flow 41 is generated in For example, if the flow velocity of the air flow 41 is 7.5 m / s, the acceleration of the particle fall is about 1Z2 during free fall, and the time during which the particle is subjected to electrostatic force becomes longer. In addition, since the air flow 41 is generated in the separation space 77 in a direction to provide gravity resistance, the distance between the particles can be further increased. As a result, the particles reach the collection container In the meantime, the horizontal movement distance drawn to the ground electrode 1 side by electrostatic force is about 30 cm, and the sorting accuracy is improved. In addition, the voltage required to obtain the same travel distance of 15 cm as in the conventional sorting device can be reduced to about 1Z2 compared to the conventional sorting device.

In the second embodiment of the present invention, the same effect can be obtained by using a nitrogen gas or other gas air flow instead of the force air flow 41 using the air flow 41.

Embodiment 3 of the present invention describes a sorting method in the case where the mixing ratio of the mixture of chargeable particles to be sorted is not equivalent. The actual mixing ratio of charged particles is often not the same. If the mixing ratio of the charged particles and the charged particles is biased to either direction, there will be a difference in charge when the particles are charged by friction. Arise. For example, if the charged particle 31 and the charged particle 32 having a specific gravity particle diameter of 3 mm have a mixing ratio of 1: 4, the charge amount of the charged particle 31 is 0.6 nC. The charge amount is about -0.15 nC.

FIG. 3 is a schematic configuration diagram of a conventional electrostatic sorting apparatus. As shown in Fig. 3, ground electrode 1 with a width of 8 cm and high-voltage applying electrode 2 are installed facing each other at a distance of 10 cm, and a separation space of 60 cm is separated downward from both electrodes + charged particle collection container 61 and charged particles Install recycle container 62. A high voltage power supply 5 is connected to the high voltage application electrode 2 and a voltage of 40 kV is applied, and an electrostatic field is generated between the two electrodes. At this time, if the mixture of charged particles is charged by stirring or the like and passes through the electrostatic field, the + charged particles 31 collide with the ground electrode 1 and adhere to the ground electrode 1 or -Since it rebounds toward the charged particle collection container 62, the sorting accuracy of the mixture is lowered. In addition, the moving distance in the horizontal direction that is attracted to the high voltage application electrode 2 side by electrostatic force before the charged particles 32 reach the collection container is about 9 cm.

FIG. 4 is a schematic configuration diagram of an electrostatic sorting device according to Embodiment 3 of the present invention. The difference from the conventional sorting device in FIG. 3 is that the electrodes are a mesh ground electrode 11 and a mesh high voltage application electrode 21, and an air flow 41 is generated parallel to the electrostatic field from the mesh ground electrode 11 side to the mesh high voltage application electrode 21 side. The point is that the air supply / exhaust device 7 to be generated is installed on the mesh ground electrode 11 side. Specifically, as shown in Fig. 4, a mesh ground electrode 11 (first electrode) 8 cm wide and a mesh height The pressure applying electrode 21 (second electrode) is placed at a distance of 10 cm, and a separation path of the object to be sorted is provided between the two electrodes. In addition, a + charged particle collection container 61 and a -charged particle collection container 62 are installed with a separation space of 60 cm downward from both electrodes, and air supply / exhaust for generating an air flow 41 in a direction parallel to the electrostatic field. Device 7 is installed on the mesh ground electrode 11 side. A high voltage power source 5 is connected to the reticulated high voltage application electrode 21 and a voltage of 40 kV is applied, and an electrostatic field is generated between the two electrodes. Note that the first electrode and the second electrode may be misaligned between the mesh ground electrode 11 and the mesh high voltage application electrode 21! /.

[0025] For example, if the flow velocity of the air flow 41 is 5.8 m / s, the collision of the + charged particles 31 with the reticulated ground electrode 11 is suppressed, and at the same time, the charged particles 32 are attracted to the reticulated high voltage application electrode 21 side. The horizontal movement distance is about 20cm, which shows that the sorting accuracy is improved over the conventional sorting device.

[0026] For these reasons, it is possible to suppress the collision of the selection object passing through the electrostatic field with the electrode.

In the third embodiment of the present invention, the same effect can be obtained by using a nitrogen gas or other gas air flow instead of the force air flow 41 using the air flow 41.

FIG. 5 is a schematic configuration diagram of an electrostatic sorting device according to Embodiment 4 of the present invention. Embodiment 4 of the present invention generates an air flow in a direction that provides an anti-gravity force to the electrostatic field generated between the electrodes and the separation space below both electrodes, and is parallel to the electrostatic field. In order to generate an air flow, an air supply / exhaust device that generates an air flow in each direction is arranged.

[0029] As shown in FIG. 5, a mesh ground electrode 11 (first electrode) and a mesh high voltage applied electrode 21 (second electrode) having a width of 8 cm are disposed at an interval of 10 cm. Between the electrodes is a falling path for the object to be sorted. In addition, a net + charged particle collection container 63 and a net-charged particle collection container 64 are installed with a separation space 77 of 60 cm downward from both electrodes. A high voltage power source 5 is connected to the net-like high voltage application electrode 21 and a voltage of 40 kV is applied, and an electrostatic field is generated between the electrodes. In addition, an air supply / exhaust device 7 for generating an air flow 41 parallel to the electrostatic field from the mesh ground electrode 11 side to the mesh high voltage applied electrode 21 side is meshed. Installed on the ground electrode 11 side, and further contains a second air supply / exhaust device 71 for generating a second air flow 42 in a direction that provides resistance against gravity against the electrostatic field and separation space. Install below the vessel. The first electrode and the second electrode may be misaligned between the mesh-like ground electrode 11 and the mesh-like high-voltage application electrode 2! /.

In a conventional sorting apparatus as shown in FIG. 3, when a mixture of charged + charged particles 31 and −charged particles 32 is passed through an electrostatic field, + charged particles 31 are grounded electrodes 1 The horizontal movement distance that is attracted to the high voltage application electrode 2 side by the electrostatic force until the charged particles 32 reach the collection container is about 9 cm.

On the other hand, in the electrostatic sorting device according to Embodiment 4 of the present invention, for example, the flow rate of the air flow 41 is set to 5.8 m / s, and the flow rate of the second air flow 42 is set to 7.5 m / s. Then, the collision of + charged particles 31 with the reticulated ground electrode 11 is suppressed and it moves about 28 cm to the reticulated ground electrode 11 until it reaches the collection container, until the charged particles 32 reach the collection container. It moves about 24 cm to the mesh-like high voltage application electrode 21 side. Therefore, it is possible to configure an electrostatic sorting device capable of sorting with sufficiently high accuracy.

[0032] From these facts, the time required for the selection object to pass through the electrostatic field is extended as compared with the conventional case, so that the selection accuracy is improved, and the voltage necessary for obtaining the same selection accuracy as before can be reduced. Become. Furthermore, the collision of the selection target object passing through the electrostatic field with the electrode can be suppressed.

In the fourth embodiment of the present invention, the same effect can be obtained by using a nitrogen gas or other gas air flow instead of the force air flow 41 using the air flow 41.

[0034] Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. Innumerable variations not illustrated The power of the scope of the present invention It is understood that the power can be assumed without departing.

Claims

The scope of the claims

[1] a first electrode (1) disposed on one side of a dropping path of the objects to be sorted (31, 32);

A second electrode (2) disposed opposite to the first electrode (1) on the other side of the drop path;

First air flow generating means for generating an air flow in a direction that provides resistance against gravity against an electrostatic field generated between the first electrode (1) and the second electrode (2);

An electrostatic sorting device comprising:

[2] a first electrode (11) arranged on one side of the dropping path of the sorting object (31, 32);

A second electrode (21) disposed opposite to the first electrode (11) on the other side of the drop path;

Second air flow generating means for generating an air flow (41) in a direction parallel to the electrostatic field with respect to an electrostatic field generated between the first electrode (11) and the second electrode (21);

An electrostatic sorting device comprising:

[3] A first electrode (11) disposed on one side of the drop path of the sorting object (31, 32);

First air flow generating means for generating an air flow (42) in a direction to provide an anti-gravity force against an electrostatic field generated between the first electrode (11) and the second electrode (21); ,

An electrostatic sorting device comprising:

[4] In the electrostatic sorting device according to claim 1,

The first air flow generating means includes an air supply / exhaust device (7), and the air supply / exhaust device (7) is disposed above the first electrode (1) and the second electrode (2). A characteristic electrostatic sorting device.

[5] In the electrostatic sorting device according to claim 1,

The apparatus further comprises a net-like collection container (63, 64) for collecting the selection object (31, 32), the first air flow generation means includes an air supply / exhaust device (71), and the air supply / exhaust device (71) in front An electrostatic sorting device, which is disposed below the net-like collection container (63, 64).

[6] In the electrostatic sorting device according to claim 2,

The first electrode (11) and the second electrode (21) are reticulated,

The second air flow generating means includes an air supply / exhaust device (7), and the air supply / exhaust device (7) is disposed on one side of the first electrode (11) or the second electrode (21). An electrostatic sorting device characterized in that:

[7] In the electrostatic sorting device according to claim 1 or claim 3,

A recovery container (61, 62) for recovering the selection object (31, 32) across a space below the first electrode (1) and the second electrode (2);

The electrostatic sorting apparatus according to claim 1, wherein the first airflow generating means generates an airflow (41) in a direction in which the space is also provided with an anti-gravity force.

[8] (a) a step of generating an electrostatic field;

(b) generating an air flow (41) in a direction to provide gravity resistance to the electrostatic field generated by the step (a);

(c) dropping the object to be sorted (31, 32) so as to pass through the electrostatic field, and an electrostatic sorting method comprising:

[9] (d) generating an electrostatic field;

(e) generating an air flow (41) in a direction parallel to the electrostatic field with respect to the electrostatic field generated by the step (d);

(f) dropping the sorting object (31, 32) so as to pass through the electrostatic field, and an electrostatic sorting method comprising:

[10] (g) a step of generating an electrostatic field;

(h) generating an air flow (42) in a direction to provide gravity resistance to the electrostatic field generated by the step (g);

(i) generating an air flow (41) in a direction parallel to the electrostatic field with respect to the electrostatic field generated by the step (g);

(j) dropping the sorting object (31, 32) so as to pass through the electrostatic field, and an electrostatic sorting method comprising:

[11] In the electrostatic sorting method according to claim 8,

The step (b) includes a step of generating the airflow by an action from above the electrostatic field.

[12] In the electrostatic sorting method according to claim 8,

(k) The process of collecting the fallen objects (31, 32)

Further comprising

The container (63, 64) to be collected is net-like, and the step (b) includes a step of generating the airflow by an action from below the container (63, 64).

[13] In the electrostatic sorting method according to claim 9,

The electrode (11, 21) has a mesh shape, and the step (e) includes a step of generating the airflow by an action from one side of the electrode (11, 21). Selection method.

[14] In the electrostatic sorting method according to claim 8 or claim 10,

(1) A step of recovering the selection objects (31, 32) with a space below the electrodes (1, 2)

The method according to claim 1, further comprising: generating an air flow (41) in a direction in which a force against gravity is also applied to the space in the step (b) or the step (h).