JP2017035670A - Screening equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide screening equipment which can remove a minute magnetic foreign matter from a statically charged particulate matter.SOLUTION: A resin pellet introduced into a raw material hopper 3 is transferred from the raw material hopper 3 to a trough 11 of a vibration feeder 5. The resin pellet of a substantially constant amount per a unit time is transferred to an upper end of a slope 20 of a magnetic suction area 7 via a transfer pipe 13 by the trough. An ionizer 30 is provided on the trough 11, and electricity of the resin pellet is removed by positive ion or negative ion supplied from an ion supply port of the ionizer 30. The electricity-removed resin pellet flows down along the slope 20. A magnet 22 is located on the slope 20, and the magnet 22 applies magnetic field to the resin pellet on the slope 20 thereby removing a magnetic foreign matter. The resin pellet, from which the magnetic foreign matter is removed, is accumulated in a temporary accommodation hopper 9.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sorting device for removing magnetic foreign matters such as metallic foreign matters from a chargeable granular material.

  As a chargeable granular material, for example, resin pellets are formed by extruding a molten polymer in a strand form from a strand die and cutting with a pelletizer, as disclosed in Patent Document 1. The formed resin pellets are stored in a flexible container or the like.

  However, when the strand-like resin is cut into a pellet by a metal cutter, a magnetic foreign substance such as a metallic foreign substance (hereinafter referred to as a magnetic foreign substance) may be mixed into the resin pellet. The size of magnetic foreign substances varies from several μm to several hundreds of μm, and foreign substances having a size that is difficult to identify visually may be mixed in. If magnetic foreign substances are mixed into the resin pellets, it also affects the quality of a processed product produced by melting and processing the resin pellets. Therefore, it is necessary to remove the magnetic foreign substances from the resin pellets.

  As a separation device for removing the magnetic material from the resin pellets, for example, a conveyance belt that conveys the resin pellets, a driving roll around which the conveyance belt is wound to give a driving force, and a driven roll that forms a pair with the driving roll and has a magnetic force The device is known. In such an apparatus, the magnetic substance mixed in the resin pellets on the conveyor belt is attracted and removed by the magnetic force of the magnet roll.

JP 2000-313745 A

However, in the prior art, an apparatus for removing the magnetic material mixed in the chargeable granular material such as the resin pellet together with the pellet has been proposed, but in practice, it has not been sufficiently removed. In particular, fine magnetic foreign matters of 100 μm or less are difficult to remove because they adhere to the resin pellets due to static electricity.
In some cases, the quality of the manufactured product may be affected by manufacturing the product while processing such a minute magnetic foreign substance attached to the resin pellet.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sorting apparatus capable of removing minute magnetic foreign substances from a chargeable granular material.

In order to achieve the above object, the characteristics of the sorting apparatus of the present invention are as follows (1) to (7):
(1)
The device of the present invention
A transfer path for transferring the chargeable granular material supplied from the raw material hopper to the processing apparatus side;
A static eliminator that is disposed on the transfer path, and supplies ions to the transfer path to neutralize the chargeable granular material;
A magnet that is disposed on a transfer path downstream of the static eliminator, forms a magnetic field in the transfer path, and attracts magnetic foreign matter;
It is provided with.
(2)
In addition, a movement control mechanism for moving a substantially constant amount of the chargeable granular material per unit time in the transfer path is provided.
(3)
In addition, the transfer path has a slope on the raw material hopper side is high and the processing apparatus side is low,
The chargeable granular material is neutralized by the static eliminator when flowing down the slope.
(4)
In addition, a temporary storage hopper for temporarily storing the charged powder particles discharged from the raw material hopper below the raw material hopper,
The chargeable granular material is neutralized by the static eliminator when it falls to the temporary storage hopper by gravity.
(5)
Further, a substantially uniform magnetic field is formed in the width direction by disposing a rectangular magnet extending in the width direction substantially perpendicular to the moving direction of the chargeable granular material on the slope. .
Moreover, you may provide the 2nd magnet which makes a counter electrode with the said magnet.
(6)
The static eliminator is characterized in that the air pressure of the air containing the ions is 0.5 MPa or less. Preferably, the air wind pressure is 0.3 MPa or less, more preferably the air wind pressure is 0.2 MPa or less.
(7)
Further, the magnet is arranged adjacent to the downstream side of the static eliminator. By arranging magnets next to each other on the downstream side of the static eliminator, magnetic adsorption can be performed immediately after static elimination, and magnetic foreign matters can be efficiently removed.

According to the apparatus of the present invention, after the static eliminator supplies ions to the chargeable granular material such as a resin pellet that moves in the transfer path to remove the charge, the magnet is attached to the chargeable granular material in the transfer path. On the other hand, since the magnetic field is applied, the magnetic foreign matter can be adsorbed and removed from the chargeable granular material without being affected by the electrostatic force. In particular, it is possible to remove magnetic foreign matters having a size of about 50 μm.
In addition, by arranging the magnets next to each other on the downstream side of the static eliminator, it is possible to remove magnetic foreign substances from the chargeable powder particles while reducing the charge again due to collision of the charged powder particles that have been neutralized. The action level of magnetic force on the chargeable granular material can be increased.
Furthermore, by moving a substantially constant amount of the chargeable granular material per unit time in the transfer path and supplying air containing ions in a constant amount per unit time, the chargeable granular material The magnetic foreign matter can be removed with a magnet after the charge is removed without unevenness.
The magnetic flux density is preferably 1 Tesla or higher. However, even when a 0.6 Tesla magnet is used, the magnetic foreign matter is sufficiently removed if the distance between the magnet and the chargeable granular material can be maintained at 1 mm or less. be able to.

1 is a schematic view of a first embodiment of the present invention. It is the fragmentary perspective view which observed the slope and magnet in the 1st embodiment from diagonally. It is the schematic of the 2nd embodiment of this invention. It is the schematic of the 3rd embodiment of this invention. It is the fragmentary perspective view which observed the ionizer, slope, and magnet in the 4th embodiment from diagonally. It is the schematic of the 5th embodiment of this invention.

The first embodiment of the present invention will be described below.
As shown in FIG. 1, the sorting apparatus 1 raw material hopper 3 of the present invention is combined, and the sorting apparatus 1 includes a vibration feeder (movement control mechanism) 5, a magnetic adsorption region 7, and a temporary storage hopper 9. The raw material hopper 3 has an opening 3a for feeding resin pellets at the top, and a discharge port 3b for discharging resin pellets to the outside at the bottom.
A vibration feeder 5 is disposed below the discharge port 3b of the raw material hopper 3, and a trough (first transfer path) 11 that receives resin pellets discharged from the discharge port 3b is disposed. The trough 11 is provided so as to freely vibrate by an electromagnetic solenoid (not shown), and by this vibration, the resin pellets in the trough 11 are at a substantially constant rate per unit time and are intermediate from the raw material hopper side which is the upstream side to the downstream side. It is transferred to the storage hopper side.
A transfer pipe (second transfer path) 13 is provided at the lower end of the trough 11 so that the resin pellets can move from the trough 11 into the transfer pipe 13. The transfer pipe 13 magnetically transfers the resin pellets from the trough 11. Transfer to the adsorption area 7.

  An ionizer (static eliminator) 30 is disposed above the trough 11, and ions are supplied from the ionizer 30. The ionizer 30 can supply positive (positive) ions and negative (negative) ions, and the supply amount of positive ions and negative ions is controlled by a controller (not shown).

  The ionizer includes a discharge needle for positive ions and a discharge needle for negative ions. By applying a voltage to each discharge needle, a corona discharge is generated, and positive ions or negative ions generated thereby are supplied to an ion supply port (illustrated). Is omitted). When the ionizer 30 is disposed on the trough 11 of the vibration feeder 5, the supply port of the ionizer 30 is directed to the trough 11, and thereby ions supplied from the ion supply port are filled into the trough 11.

The positive ion concentration or negative ion concentration may be adjusted manually or automatically. In order to adjust the ion concentration supplied from the ionizer, the ion supply amount may be adjusted according to the charge amount of the resin pellets. As a result, the resin pellets in the trough 11 can be neutralized, static electricity can be removed from the resin pellets supplied to the magnetic adsorption region 7, and the magnetic adsorption can be prevented from being obstructed or shut out by electrostatic force. can do.
In order to disperse the ions in the trough 11 as uniformly as possible, air containing air (air) may be supplied at a predetermined wind pressure. The wind pressure is not particularly limited, but if the resin pellets move, they collide with each other and generate static electricity. Therefore, the wind pressure at which the resin pellets are stationary is preferable. By supplying air containing ions, the resin pellets move in the atmosphere filled with the air, and thereby each individual resin pellet can be discharged in a relatively short time. In particular, static elimination can be achieved in a short time compared to the type of static elimination that is grounded, which improves the yield and enables a compact device.

One end of the transfer pipe 13 communicates with the trough 11 and the other end communicates with the magnetic adsorption region 7. The resin pellet introduced from one end of the transfer pipe 13 is transferred to the other end side and supplied to the magnetic adsorption region 7 from the other end. The vibration feeder 5 has a function of transferring a substantially constant amount of resin pellets, whereby the amount of resin pellets supplied from the vibration feeder 5 to the transfer pipe 13 is controlled to a substantially constant amount. Further, the amount of resin pellets supplied to the magnetic adsorption region 7 via the transfer pipe 13 is also controlled to a substantially constant amount.
In addition, although the vibration feeder was illustrated here, as long as it is a mechanism which can transfer a substantially constant amount of resin pellets, any mechanism may be used without being limited thereto. For example, a mechanism using a screw feeder or a rotary valve may be used. Even with such a mechanism, a substantially constant amount of resin pellets can be transferred per unit time.

The resin pellet is formed by a known method.
For example, it is formed by heat-kneading a raw material resin, extruding it into a strand shape or a rod shape through a strand die, and cutting with a cutter such as a cutter. The kneading can be performed with, for example, a mixer, a single / biaxial kneader, a Brabender, or the like. The resin temperature during kneading is typically 20 to 150 ° C. higher than the higher one of the glass transition temperature and melting point of the resin.
When extruded into a strand shape, the pellet shape is circular or oval in cross section, and the average diameter is 0.1 to 15 mm. The length of the pellet is 0.1 to 15 mm, and may be appropriately changed according to the purpose.
The strand cutting mode includes, for example, a cold cutting method in which a rod-like strand extruded from a die hole is solidified by water cooling and a hot cutting method in which cutting is performed immediately after being extruded from a die hole. .

  In the production of resin pellets, the charge may be briefly removed to prevent the pellets from sticking to each other. An example of the static elimination method is an ion shower. For example, an ion shower includes a method of ionizing and blowing oxygen molecules and nitrogen molecules in the air. The timing of the ion shower is preferably, for example, when a strand before cutting is formed, when a strand is cut to form a pellet, and when the formed pellet is accommodated in a flexible container, etc. Therefore, ion showers are often omitted.

  Examples of resin pellets include polyvinyl chloride, ethylene / vinyl acetate copolymer, ethylene / vinyl chloride copolymer, polystyrene ethylene / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polystyrene, AS resin, MBS. Resins, ABS resins, other aromatic vinyl compound resins, nylon 6, polyacetal / nylon 6, nylon 6.6, acrylic resins, other polyamides, polybutylene terephthalate, polyethylene terephthalate, other polyesters, polycarbonates, polyphenylene sulfide , Polyetherimide, polyarylate, polyethylene, polypropylene and the like, and mixtures thereof.

The magnetic adsorption region 7 can be constructed in various modes. For example, for example, a slope 20 (third transfer path) through which resin pellets flow down and a certain interval are disposed on the slope 20. The magnet 22 can be configured to be provided in a housing (not shown). The slope 20 has, for example, an inclined surface (moving surface) 20a having an inclination of 15 ° to 30 ° from the horizontal direction so that the resin pellets can flow down on the inclined surface 20a. The distance between the slope 20 and the magnet 22 may be any distance that allows the resin pellets to pass therethrough. However, if the distance is too large, the strength of the magnetic field acting on the resin pellets will decrease, so the resin pellets do not come into contact with each other. 22 is preferably as close to the slope 20 as possible.
In addition, what is necessary is just to make the angle of a slope a steeper angle when raising the transfer speed of a resin pellet. In this case, by changing the slope angle to a steeper angle and increasing the supply amount of ions from the ionizer, the charge can be eliminated while increasing the transfer speed of the resin pellets. In particular, when using a belt conveyor, the relative speed difference when placing resin pellets on the belt conveyor must be reduced to some extent, which requires a complicated configuration. In the present invention, a simple configuration is used. It is possible to eliminate static electricity while increasing the transfer speed of the resin pellets.

The magnetic adsorption region 7 is provided with a slope 20 and a magnet 22 for transferring resin pellets to the temporary storage hopper 9 side. The shape of the magnet 22 is not particularly limited, but a magnet that can form a uniform magnetic field in the width direction of the trough with respect to the resin pellet moving on the slope 22 is preferable.
For example, as shown in FIG. 2, the magnet 22 may be formed in an elongated rectangular shape and may have a magnetic attracting surface 22a that generates a substantially uniform magnetic flux density in the longitudinal direction. If a plurality of magnets are simply arranged in a direction substantially perpendicular to the transfer direction, a place where the magnetic field strength is strong and a weak place is formed in the direction substantially perpendicular to the transfer direction. A magnet having a magnetic attracting surface 22a that forms a substantially uniform magnetic flux density in the direction can form a uniform magnetic field. When such a magnet 22 is used, the magnet 22 is arranged so that the longitudinal direction of the magnet 22 is aligned with a direction substantially perpendicular to the resin pellet transfer direction and the magnetic attraction surface 22 a faces the slope 20. The magnetic adsorption surface 22a and the slope 20 are arranged at a predetermined interval, and the resin pellet is passed between the magnetic adsorption surface 22a and the slope 20. The distance between the magnetic attracting surface 22a and the slope 20 is preferably as narrow as possible from the viewpoint of the magnetic strength given to the resin pellets.

The magnet 22 may be a permanent magnet or an electromagnet. In the case of an electromagnet, power supply is required, but the magnetic field strength to be formed can be freely controlled. By removing the magnetic foreign matter from the resin pellet using the magnet 22 as described above, it is possible to remove the magnetic foreign matter from the resin pellet without unevenness.
Magnetic foreign matter mixed in the resin pellets flowing down the slope 20 is attracted to the attracting surface 22a of the magnet 22. However, the magnet 22 is continuously used by removing and collecting the magnetic foreign matter on the attracting surface 22a periodically by the user. can do.

  The distance between the slope 20 and the magnetic adsorption surface 22a can be adjusted as appropriate. For example, a magnet 22 having a surface magnetic flux density of 10000 gauss (1.0 Tesla) is separated from the slope 20 by 10 mm through which the resin pellet can pass, and about 0.5 is added to the resin pellet passing between the slope 20 and the magnet 22. A magnetic field of Tesla (5000 Gauss) may be applied. Further, the magnet 22 having a stronger surface magnetic flux density of 1.5 Tesla, 2.0 Tesla, 2.5 Tesla, 2.7 Tesla, and 3.0 Tesla while setting the distance between the slope 20 and the magnet 22 to 10 mm. May be used to form a stronger magnetic field. The distance between the slope 20 and the magnetic adsorption surface 22a is preferably set at an appropriate interval according to the size of the resin pellet so that the resin pellet does not contact the magnetic adsorption surface 22a.

The resin pellets transferred to the magnetic adsorption region 7 by the transfer pipe 13 are placed on the upper end of the slope 20, and the resin pellets placed on the upper end of the slope 20 flow down the slope 20 toward the lower end.
As described above, the magnet is, for example, 0.5 Tesla or more, preferably 0.8 Tesla, more preferably 1.0 Tesla, still more preferably 1.5 Tesla, still more preferably 2.5 to 2.7 Tesla or more. It has a magnetic flux density, and a magnetic field is formed on the slope by this magnetic flux density. Magnetic force from the magnet 22 acts on the resin pellets flowing down the slope 20, whereby magnetic foreign matters mixed in the resin pellets are attracted and removed by the magnets.
The size of magnetic foreign matter that can be removed varies from 20 μm to several hundred μm. In particular, the magnet 22 can remove magnetic foreign matter having a size of 20 μm to 100 μm, and in particular, it can precisely remove magnetic foreign matter having a size of around 50 μm. . In addition, the experiment which removed the magnetic foreign material about 50 micrometers from the resin pellet is described in Examples 1-4 mentioned later. Whether or not magnetic foreign substances are attached to the resin pellets (attached pellets: NG pellets) may be inspected using a scanning electron microscope or the like, or monitoring of magnetic field fluctuations caused by magnetic foreign substances moving in the magnetic field The inspection method is not particularly limited.

Next, the operation of the present invention will be described.
The resin pellets charged into the raw material hopper 3 are transferred from the raw material hopper 3 to the trough 11 of the vibration feeder 5, and the resin pellets transferred to the trough 11 are united from one end side to the other end side of the trough 11 by vibration of an electromagnetic solenoid, for example. It is transported at a substantially constant rate per hour. The resin pellets sent to the other end of the trough 11 are transferred to the upper end of the slope 20 of the magnetic adsorption region 7 through the transfer pipe 13.
The trough 11 is provided with an ionizer 30, and the resin pellets are neutralized by positive ions or negative ions supplied from an ion supply port of the ionizer 30. The resin pellets that have been neutralized in the transfer pipe 13 are sent to one end of the slope 20 through the transfer pipe 13, and the resin pellets flow down on the slope.
A magnet 22 is disposed on the slope 20, and the magnet 22 applies a magnetic field to the resin pellets flowing down the slope 20 to remove magnetic foreign matters. A clearance of a predetermined interval is formed between the magnetic attraction surface 22a of the magnet 22 and the slope 20, and the resin pellets pass through this clearance. At this time, the magnetic foreign matter adhering to or mixed in the resin pellet is attracted to the magnet 22 and removed. The resin pellets from which the magnetic foreign matter has been removed are stored in the temporary storage hopper 9 and supplied from the temporary storage hopper 9 to the processing apparatus.
Conventionally, since the electrostatic force has exceeded the magnetic force, the number of magnetic foreign matters that can be removed by the magnet 22 is limited, and it has been particularly difficult to remove magnetic foreign matters having a size of 50 to 60 μm or less. In the present invention, since the magnetic foreign matter is magnetically adsorbed by the magnet 22 after the resin pellet is previously neutralized by the ionizer 30, the influence of electrostatic force can be reduced and the magnetic foreign matter having a size of about 50 μm can be removed more reliably than before. In addition, since the ionizer 30 removes electricity when a substantially constant amount of resin pellets are transferred by the vibration feeder 5, the resin pellets can be removed without unevenness.

Second Embodiment In the above description, the ionizer 30 is arranged on the trough 11. However, the arrangement position of the ionizer is not limited to this, and may be appropriately changed. As shown in FIG. 3, for example, an ionizer 42 may be disposed in the transfer pipe 40. By disposing the ionizer 42 in the transfer pipe 40, the resin pellets can be neutralized immediately before the resin pellets are transferred to the magnetic adsorption region 7, and the influence of electrostatic force can be further reduced, more reliably around 50 μm. Can be removed.
In order to disperse the ions as uniformly as possible in the transfer tube 40, air containing ions (air) may be supplied at a predetermined wind pressure. The wind pressure is not particularly limited, but if the resin pellets move, they collide with each other and generate static electricity. Therefore, a wind pressure at which the resin pellets are not blown away is preferable.

Third Embodiment Further, as shown in FIG. 4, ionizers 30 and 52 may be provided on both the trough 11 and the transfer pipe 50 to supply positive or negative ions, and the resin pellets may be neutralized. Even with such a configuration, the resin pellets can be neutralized, and in particular, static electricity generated when the resin pellets collide with each other during transfer to the magnetic adsorption region can be further reduced.

Fourth Embodiment In the above description, the resin pellets are neutralized on the trough 11 and the magnetic foreign matters are removed in the magnetic adsorption region. However, the ionizer is not limited to this location, for example, it is arranged adjacent to the upstream side of the magnet on the slope. May be.
As shown in FIG. 5, by disposing the ionizer 60 on the upstream side of the magnet 22, the effect of static electricity in the magnetic adsorption can be further reduced by removing the charge of the resin pellet immediately before the magnetic adsorption. With such a configuration, the resin pellets flowing down from the upstream side to the downstream side of the slope 20 may be neutralized to remove the magnetic foreign matter.

5th Embodiment Moreover, although the trough and the slope were provided and the resin pellet was transferred in the said 1st-3rd embodiment, the embodiment of this invention is not restricted to this. For example, a temporary storage hopper is provided below the raw material hopper, an ionizer and a magnet are disposed between the raw material hopper and the temporary storage hopper, and the resin pellets are neutralized, and then magnetic foreign substances in the resin pellets are removed. Also good.
As shown in FIG. 6, the resin pellets discharged from the lower part of the raw material hopper 100 freely fall by gravity and enter the charge removal region 110 provided with the ionizer 108, and the resin pellets are discharged by positive or negative ions.
The neutralized resin pellets enter the magnetic adsorption region 120 provided below the neutralization region 110 and freely fall within the magnetic field. The magnetic adsorption region 120 is provided with a pair of magnets 122 that are spaced apart from each other by a certain distance in the horizontal direction, and the resin pellets freely fall between the magnets 122.
Temporary storage hopper (not shown) in which the magnetic foreign matter mixed in the resin pellet when freely falling in the magnetic field is attracted and removed by the magnet 122, and the resin pellet from which the magnetic foreign matter has been removed is disposed below the magnetic adsorption region 120. Is housed in. Even with such a configuration, magnetic foreign substances can be removed from the resin pellet, and a high-quality resin pellet can be provided.

The ion balance may be adjusted manually during static elimination, but may be adjusted automatically.
For example, a sensor for detecting the charge level is provided in the transfer path, and a signal from this sensor is processed to determine the charge level of the resin pellet by the detection circuit. Based on the charge level determined by the detection circuit, positive and negative ions are detected. Adjust the supply amount.
By eliminating the charge of the resin pellets with such a configuration, it is possible to save time and effort for adjusting the charge level of the resin pellets, and it is possible to provide a highly convenient sorting apparatus.

[Example 1]
In the first embodiment, the resin pellets were neutralized to magnetically adsorb magnetic foreign substances. The implementation conditions are as follows:
・ Ionizer (Panasonic Device SUNX ER-X016) is placed on the trough of the vibration feeder;
-The magnetic flux density of the magnet (electromagnet) is 27000 gauss (2.7 Tesla);
・ The clearance between the moving surface of the resin pellet and the magnet is 10 mm;
-Two types of resin pellets are used: polypropylene (hereinafter PP) and polyethylene (hereinafter PE);
・ The wind pressure of air containing positive / negative ions from the static eliminator is 0.5 MPa.

The pellet non-defective rate was calculated from the following formula:
Non-defective pellet ratio = [(total number of inspection pellets−number of NG pellets) / total number of inspection pellets] × 100
Polyethylene and polypropylene pellet yield rates are listed in the following results.
In addition, about the NG pellet, it was determined whether it was a NG pellet by monitoring the fluctuation | variation of the magnetic field at the time of moving a pellet within a magnetic field. In particular, a minute magnetic foreign substance having a size of about 50 μm was detected by monitoring the magnetic field, and the detected pellets were counted as NG pellets.
[result]
-The yield rate was about 84% for PP and about 90% for PE.

[Example 2]
In the second embodiment, the resin pellets were neutralized to magnetically adsorb magnetic foreign substances. The implementation conditions are as follows:
・ Ionizer (Panasonic Devices SUNX ER-X016) is placed on the transfer pipe;
-The surface magnetic flux density of the magnet is 27000 gauss (2.7 Tesla);
・ The clearance between the moving surface of the resin pellet and the magnet is 10 mm;
・ The wind pressure of air containing positive / negative ions from the static eliminator is 0.3 MPa.
* Measurement of charge level of resin pellets discharged from the transfer pipe and confirmation of 0V Polyethylene and polypropylene pellet yield rates are summarized in the following results.
[result]
-The non-defective product rate was about 94% for PP and the non-defective rate was about 97% for PE.

[Example 3]
In the third embodiment, the resin pellets were neutralized to magnetically adsorb magnetic foreign substances. The implementation conditions are as follows:
・ Ionizers (ER-X016 made by Panasonic device SUNX) are placed on both the trough and the transfer pipe;
-The surface magnetic flux density of the magnet is 27000 gauss (2.7 Tesla);
-Use two types of resin pellets: polypropylene and polyethylene;
・ The wind pressure of air containing positive / negative ions from the static eliminator is 0.2 MPa.
The percentages of non-defective pellets of polyethylene and polypropylene are summarized in the following results.
[result]
-The non-defective product rate was about 96% or more for PP, and the non-defective rate was about 97% for PE.

[Example 4]
In the fourth embodiment, the resin pellets were neutralized to magnetically adsorb magnetic foreign substances. The implementation conditions are as follows:
・ Ionizer (Panasonic device SUNX ER-X016) is placed on the slope;
-The surface magnetic flux density of the magnet is 10,000 Gauss (1.0 Tesla);
-Use two types of resin pellets: polypropylene and polyethylene;
・ The clearance between the moving surface of the resin pellet and the magnet is 10 mm;
・ The wind pressure of air containing positive / negative ions from the static eliminator is 0.2 MPa.
The percentages of non-defective pellets of polyethylene and polypropylene are summarized in the following results.
[result]
-The non-defective product rate was about 94% for PP and the non-defective rate was about 97% for PE.

[Comparative example]
While supplying a certain amount of resin pellets per unit time with a vibration feeder, magnetic foreign matter was magnetically adsorbed with a magnet on the moving surface (plane). The implementation conditions are as follows:
・ No neutralization of resin pellets ・ Magnetic surface magnetic flux density of 27000 gauss (2.7 Tesla);
-Use two types of resin pellets: polypropylene and polyethylene;
-Clearance between moving surface and magnet is 10mm;
The percentages of non-defective pellets of polyethylene and polypropylene are summarized in the following results.
[result]
-The non-defective product rate was 56% for PP, and the non-defective product rate was 52% for PE.

1 Sorting device 3 Raw material hopper 5 Vibrating feeder (movement control mechanism)
7 Magnetic adsorption area 9 Temporary storage hopper 11 Trough (first transfer path)
13 Transfer pipe (second transfer path)
20 slope (third transfer route)
20a Slope (moving surface)
22 Magnet 22a Magnetic adsorption surface 30 Ionizer (static eliminator)
40 Transfer pipe 42 Ionizer 50 Transfer pipe 52 Ionizer 60 Ionizer 100 Raw material hopper 108 Ionizer 110 Static elimination area 120 Magnetic adsorption area 122 Magnet

Claims (7)

A transfer path for transferring the chargeable granular material supplied from the raw material hopper to the processing apparatus side;
A static eliminator that is disposed on the transfer path, and supplies ions to the transfer path to neutralize the chargeable granular material;
A magnet that is disposed on a transfer path downstream of the static eliminator, forms a magnetic field in the transfer path, and attracts magnetic foreign matter;
A sorting device characterized by comprising:   The sorting apparatus according to claim 1, further comprising a movement control mechanism for moving a substantially constant amount of the chargeable powder particles per unit time in the transfer path. The transfer path comprises a slope with a high raw material hopper side and a low processing device side,
3. The sorting apparatus according to claim 1, wherein the chargeable particles are neutralized by the static eliminator when flowing down the slope. A temporary storage hopper for temporarily storing the charged powder particles discharged from the raw material hopper below the raw material hopper;
3. The sorting apparatus according to claim 1, wherein when the chargeable granular material falls to the temporary storage hopper by gravity, the charge is removed by the charge eliminator. 4.   A substantially uniform magnetic field is formed in the width direction by disposing a rectangular magnet extending in a width direction substantially perpendicular to a moving direction of the chargeable granular material on the slope. 3. The sorting apparatus according to 3.   6. The sorting apparatus according to claim 5, wherein the static eliminator sets a wind pressure of the air containing the ions to 0.5 MPa or less.   The sorting apparatus according to claim 5, wherein the magnet is arranged adjacent to the downstream side of the static eliminator.

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