JP5870267B2 - Sorting device - Google Patents

Description

  The present invention relates to a sorting device for sorting small pieces of a specific plastic material to be sorted for each type of plastic from a mixture of a plurality of types of plastic pieces crushed for recycling from waste home appliances and the like.

  Mass production, mass consumption, and mass disposal economic activities are currently causing global environmental problems such as global warming and resource depletion. Under such circumstances, in order to build a resource recycling society, the Home Appliance Recycling Law was fully enforced in Japan in April 2001, and used air conditioners, TVs, refrigerators, freezers, washing machines Recycling is mandatory. As a result, household electrical appliances that are no longer needed are collected and recycled by the household electrical appliance recycling plant after being crushed and separated by material using magnetism, wind power, vibration, and the like.

  Among them, metal materials are recovered with high purity for each material such as iron, copper, and aluminum by using a specific gravity sorting device or a magnetic sorting device, and a high recycling rate is realized.

  On the other hand, examples of the plastic material to be recycled mainly include polypropylene (hereinafter referred to as PP), polystyrene (hereinafter referred to as PS), acrylonitrile butadiene styrene (hereinafter referred to as ABS), and the like. These occur as shredder products in a mixed state when the home appliances are crushed together. When material recycling is performed, it is necessary to sort by plastic type, and it is a big problem that it is not possible to sort from this shredder product by plastic type. In other words, in order to recycle plastic materials, it is very important to sort the shredder products with high purity for each type of plastic. When the purity of the selected plastic material is low, not only the recycling cost is low, but also it can be used only in cascade because it is used as a mixed material in a low-grade product.

  Therefore, conventionally, in order to enable selection of plastic materials that cannot be selected by specific gravity selection, a method of detecting and selecting individual plastic materials from a shredder product using a material identification device has been proposed (see Patent Document 1).

  FIG. 6 a is a diagram showing a conventional sorting device described in Patent Document 1. As shown in FIG.

  The conventional sorting apparatus detects a light source 103 that irradiates the small piece 102 with near infrared rays and a transmitted light or a reflected light from the small piece 102 with respect to a shredder product in which plural kinds of plastic small pieces 102 flowing on the belt conveyor 101 are mixed. A light receiving element 104, a discriminating device 105 for identifying the material by the absorbance of a specific wavelength by the small piece 102 included in the shredder product, and a sorting unit 106 having a pulse air nozzle that can change whether or not to blow each small piece. . The identification device 105 discriminates the material for each of the plastic pieces 102 included in the shredder product, and blows off only the pieces 102 of the desired plastic material by the sorting unit 106, so that only the desired plastic can be selected.

  The above-described plastic material discrimination and blowing operations are performed immediately after the oblique chute 108. This is because the particle size of the small pieces 102 included in the shredder product is small, and in order to secure a transport path corresponding to the particle size, the small pieces 102 are partitioned by a partition rail 109 provided with grooves at regular intervals on the conveyor, and the individual small pieces are aligned along the grooves. This is because the apparatus is configured to slide down and blow off small pieces at the end of the groove.

  FIG. 6b is a view of the device described in FIG. 6a from above. A configuration is adopted in which a number of partition rails 109 are provided in a direction orthogonal to the transport direction. As a result, when small pieces having a uniform particle size are introduced, the small pieces regularly pass to desired positions corresponding to the identification device 105 and the sorting unit 106, and only the small pieces of plastic of the desired material are effectively separated and collected.

JP 2009-279553 A

  However, in the conventional sorting apparatus, since the small pieces overlap and approach each other during conveyance from the conveying device 101 such as a conveyor belt to the oblique chute 108, only small pieces made of plastic of a desired material are high purity and high. The recovery rate cannot be ensured. That is, when there is a lot of overlap between the small pieces, it is impossible to sort with high accuracy because there is much misjudgment of the plastic material and there is much mixing other than the small pieces of the desired material in the sorting unit 106. Therefore, there are problems that it is not possible to secure an aggregate of only small pieces of the same plastic material necessary for material recycling, and productivity is poor.

  In addition, since the identification device 105 needs to have a device configuration corresponding to a plurality of grooves partitioned by the partition rail 109, a point sensor must be arranged corresponding to each groove. That is, there is a problem in that since there is reflection on the partition rail 109, an optical sensor that scans light across the partition rail 109 using a polygon scanner, a galvano mirror, or the like and performs identification cannot be used.

In order to achieve the above object, a sorting device according to the present invention includes a supply device that continuously supplies a plurality of plastic pieces, a transfer device that transfers the supplied pieces in one direction, and the transfer device. A sorting apparatus comprising: an identification device that identifies a plastic material of an upper piece; and a sorting unit that sorts a small piece of a specific plastic material from among the plurality of pieces based on the identification result of the identification device, A plate-like separation plate is disposed upstream of the identification device in the transport direction of the apparatus and above the transport device, extends along the transport direction, and is arranged in a direction perpendicular to the transport direction. The arrangement pitch of the separation plates is selected from the range of 1 to 3 times the diameter of the circumscribed circle of the small piece.

  According to this, it becomes possible to identify pieces that are uniformly aligned without being affected by the partition rail or the like, and it is possible to improve the sorting accuracy.

  By using the present invention, a mixture of small pieces made of a plurality of types of plastic materials, in particular, a selection of pieces made of a desired plastic material with high purity from a mixture of crushed pieces of small pieces for recycling from waste home appliances.・ Can be collected.

FIG. 1 is a block diagram of a sorting apparatus for sorting small pieces of a specific plastic material according to the present invention. FIG. 2 is an enlarged view of the configuration of a sorting device for sorting small pieces of a specific plastic material according to Embodiment 1 of the present invention. FIG. 3a is a schematic view of the separator effect according to the present invention. FIG. 3b is a schematic view of the separator effect according to the present invention. FIG. 4 is a characteristic diagram showing the relationship between the separation plate pitch and the recovery rate. FIG. 5 is a characteristic diagram showing the relationship between the thickness of the separation plate and the recovery rate. FIG. 6a is a schematic diagram of a conventional separation method. FIG. 6b is a schematic diagram of a conventional separation method.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components may be denoted by the same reference numerals and description thereof may be omitted.

(Embodiment 1)
FIG. 1 is a perspective view showing a configuration of a sorting apparatus according to Embodiment 1 of the present invention.

  As shown in the figure, the sorting device 100 includes a supply device 111, a separation plate 110, and a transport device 101 such as a belt conveyor. Further, the sorting device 100 includes an identification device 105 that identifies a plastic material, which includes a light source 103 and a light receiving element 104 in a downstream portion in the transport direction (X-axis direction in the drawing) of the transport device 101. In addition, the sorting apparatus 100 includes a separation unit 106 including a plurality of pulse air nozzles that discharge air in a pulsed manner in front of the downstream side in the transport direction in the width direction (Y-axis direction in the drawing) of the transport apparatus 101, and a partition plate 107. The sorting unit 106 and the identification device 105 are controlled to be synchronized by a sequencer or the like.

  FIG. 2 is a perspective view showing an arrangement state in the vicinity of the separation plate in a state where the supply device is separated upward.

  The separation plate 110 is a plate member for preventing overlap when the small pieces 102 made of different kinds of plastic materials are overlapped with each other, and are separated from each other. And the transfer device 101. The separation plate 110 is a long thin plate-like member, and the longitudinal direction of the separation plate 110 extends along the conveyance direction (X-axis direction in the drawing) of the conveyance device 101, and the width of the separation plate 110 is the conveyance device 101. It is arrange | positioned with respect to the conveyance surface of this at perpendicular | vertical (Z-axis direction) or a crossing state. A plurality of separation plates 110 are arranged at predetermined intervals in parallel with a direction (Y-axis direction) perpendicular to the transport direction (X-axis direction) of the transport device 101 (10 sheets in the present embodiment). The separation plates 110 are connected so as to maintain an interval by using plate-like fixing means 112 extending perpendicularly (Y-axis direction) to the conveyance direction (X-axis direction) of the conveyance device 101. The fixing means 112 is arranged on the upstream side with respect to the transport direction (X-axis direction) from the end of the supply device 111 on the supply side (downstream side in the transport direction) so that the small piece 102 does not touch and stay.

  The separation plate 110 connected and fixed by the fixing means 112 is fixed to an outer frame which is a basic body of the transport apparatus 101 via the fixing means 112. Accordingly, the separation plate 110 is arranged in a fixed state without being interlocked with the transport operation of the transport device 101, for example, the movement of the belt of the belt conveyor. That is, it is a unit independent of the transport apparatus 101 without being bonded to a transport member such as a belt provided in the transport apparatus 101.

  One separation plate 110 is arranged at a position corresponding to the space between the plurality of pulse air nozzles 161 arranged in the width direction (Y-axis direction) of the transport device 101. That is, the arrangement pitch P of the pulse air nozzles 161 and the arrangement pitch P of the separation plate 110 are the same. Further, since the arrangement pitch P of the separation plate 110 is larger than the particle size of the small pieces 102, the height H of the separation plate 110 does not significantly affect the sorting performance of the sorting device 100. From the above, for example, the arrangement pitch P of the separation plates 110 may be 10 mm and the height may be 10 mm.

  Here, the particle size of the small piece 102 is a diameter of a circle through which the small piece 102 can pass.

  Next, a series of operations of the sorting apparatus 100 will be described.

  When the supply device 111 placed on the upstream side of the conveyance device 101 vibrates or swings, the plurality of small pieces 102 stacked on the supply device 111 are sequentially put into the separation plate 110 on the conveyance device 101. In the traveling direction of the transport device 101, the transport speed of the transport device 101 is overwhelmingly higher than the speed at which the supply device 111 puts the small pieces 102 into the separation plate 110 (the weight or number of small pieces 102 supplied per unit time). Since it is fast, the overlap between the small pieces 102 is eliminated.

  In the case of the present embodiment, the conveying speed of the conveying device 101 can be selected from 1 m / s to 3 m / s depending on the amount (number) of small pieces 102 to be supplied. In addition, if the small piece 102 moves on the conveyance apparatus 101 more than the conveyance state of the conveyance apparatus 101, the small piece 102 moves from the position detected by the light receiving element 104 to the sorting unit 106, and the desired small piece 102 is moved. Since it cannot be blown off, it is necessary to set the transport speed of the transport apparatus 101 to a speed at which the small piece 102 does not move due to the influence of wind and vibration.

  In the present embodiment, since the plurality of small pieces 102 are dispersed in the width direction of the transport device 101 on the separation plate 110, there is an effect of particularly suppressing the overlapping of the small pieces 102 in the width direction. Thereafter, the plurality of small pieces 102 are sequentially conveyed on the conveying device 101. The small piece 102 that has reached the vicinity detected by the light receiving element 104 is illuminated by the light source 103, thereby generating near infrared light that is a characteristic amount of each plastic material. Specifically, the plastic material constituting the small piece 102 has an absorption distribution in a near infrared band that varies depending on the material, and the small piece 102 made of a different plastic material reflects reflected light (with different spectral distribution in the near infrared light region ( Transmitted light) is generated. Here, it is preferable that the light source 103 generates light having a broad wavelength band of about 1.3 μm to 2.5 μm. Specifically, a halogen lamp can be suitably used. As the light source 103, a laser having a wide wavelength band can be used. Light having a specific spectrum due to reflection or transmission is detected by using the light receiving element 104, and the spectrum of light as a detection result is converted into digital data. The identification device 105 identifies the plastic material constituting each of the small pieces 102 in comparison with the reference spectrum. In accordance with the identification result, sorting is performed by blowing only the small pieces 102 of a desired plastic material to the collection zone 200 (see FIG. 1) far from the partition plate 107 using the pulse air nozzle 161 of the sorting unit 106 in front.

  Here, purity and recovery are defined as follows.

  The total mass of the desired plastic material small pieces 102 included in the plurality of small pieces 102 fed from the supply device 111 is A, the total mass of the desired plastic material small pieces 102 selected by the sorting apparatus 100 is B, and the sorting apparatus 100 In the case of erroneous determination or when the position control of the pulse air is disturbed by the sorting unit 106 and the total mass of the small pieces 102 other than the desired plastic material that mixes the plastic other than the desired plastic into the recovery zone 200 (see FIG. 1) is C. The purity and recovery rate are expressed as follows.

Purity (%) = B / (B + C) × 100
Recovery rate (%) = B / A × 100

  A screening test was performed using a plurality of small pieces 102 having a particle size of 8 to 10 mm, which accounted for 20% of the total mass of the shredder dust generated when the refrigerator product was crushed. The small particles 102 having other particle sizes were previously removed by sieving or dust collection, and the particle sizes of the small particles 102 used for the sorting test were made uniform.

  As described above, sufficiently high purity is required for material recycling. Therefore, a plurality of samples having different purities were intentionally prepared in advance by the above-described purity measurement method, and a physical property test was performed. From the viewpoint of impact resistance and the like, it was found that a purity of 99% or more is necessary in order to recycle materials as home appliance plastic. Then, the result of having examined about the point which can improve a recovery rate within the range, after performing a test on the conditions which made purity 99% or more is shown.

  FIG. 3 a is a schematic diagram showing the separator effect. FIG. 3b is a schematic diagram showing the separator effect.

  When the state of the plural kinds of small pieces 102 on the transfer device 101 was confirmed with a high-speed camera, the overlap of the small pieces 102 due to the two physical phenomena of FIGS. 3a and 3b can be improved by installing the separation plate 110. The effect was confirmed.

  As shown in FIG. 3a, when the two small pieces 102 are made into small pieces 102a and 102b, the small pieces 102a and the small pieces 102b are conveyed while being in contact with each other on the supply device 111 (not shown in FIGS. 3a and 3b). There may be.

  If the separation plate 110 is not present, the small piece 102a and the small piece 102b are in contact with each other and are often erroneously determined by the identification device 105. Also, the small piece 102a and the small piece 102b are blown simultaneously by the sorting unit 106. Therefore, there is a possibility that a small piece 102 of a plastic material other than desired may reach the collection zone 200.

  On the other hand, when the separation plate 110 is installed as in the present embodiment, the small piece 102a and the small piece 102b are separated in the width direction by contacting only the one small piece 102b in contact with the separation plate 110. That is, when the small piece 102b comes into contact with the separation plate 110, the position of the left and right (changes to the right in FIG. 3A) in the width direction of the transport apparatus 101 changes. On the other hand, since the small piece 102a is not in contact with the separation plate 110, the position in the width direction does not change. Since the transport speed of the transport apparatus 101 is higher than the supply speed of the supply apparatus 111, the small piece 102 supplied next does not overlap the small piece 102 supplied first. Accordingly, the small piece 102 supplied next is delayed with respect to the previously supplied small piece 102 so that they do not contact or overlap each other. As a result, since the small pieces 102 are conveyed without overlapping or contacting the conveying device 101, the probability of erroneous determination and selection is reduced, and the selection accuracy is improved.

  Next, as shown in FIG. 3 (b), when the small pieces 102 a and the small pieces 102 b are supplied in an overlapping state, both come into contact with the separation plate 110. By contact with the separation plate 110, the position of the small piece 102a is changed to the left side and the position of the small piece 102b is changed to the right side. As a result, both are separated. Even when the position of the small piece 102a and the small piece 102b changes to the same side due to contact, a difference occurs in the time until they both reach the transport apparatus 101. Therefore, the small piece 102 that has reached the transport apparatus 101 first Since it is conveyed, the overlap of the small pieces 102 is eliminated. As a result, regarding the selection of the small pieces 102 of the desired plastic material, the probability of erroneous determination / selection is reduced, so that the selection accuracy is improved.

  In addition, when desirable in FIG. 2, an arrangement relationship in which a straight line drawn in parallel with the conveying device 101 from an intermediate point between the separation plate 110 and the separation plate 110 is positioned at the center of the pulse air nozzle of the separation unit 106 arranged in front. This is the case. Thereby, the separation unit 106 can discharge pulse air to a suitable position with respect to the small pieces 102 rectified and conveyed by the separation plate 110, and the small pieces 102 of a desired plastic material can be blown off to the collection zone 200.

  Hereinafter, the conditions used in the experiment will be described.

  The discrimination conditions set in the identification device 105 greatly contribute to the purity and the recovery rate. At that time, it is often the case that purity or recovery is emphasized depending on the purpose. In order to recycle materials, it is often performed with emphasis on purity because it cannot be used if impurities above a certain level are mixed. In that case, it is necessary to reduce the contamination of the foreign matter to the limit. Therefore, as well as the small pieces 102 not overlapping on the transport device 101, when there is an overlapped small piece 102, an experiment is performed using a discrimination algorithm that discriminates this and makes it invalid to blow off the collection zone 200. It was.

  Specifically, when it is determined that there is a small piece 102 other than the desired plastic material on the periphery of the small piece 102 of the desired plastic material, the small piece 102 other than the desired plastic material is brought together with the small piece 102 of the desired plastic material by pulse air. Since the probability of being blown away and mixed into the collection zone 200 is increased, the probability of foreign matter mixing is reduced by setting the small pieces 102 of the desired plastic material and the small pieces 102 other than the desired plastic material to be blown away. More specifically, if there is a small piece 102 other than the desired plastic material on the conveying apparatus 101, “discharge prohibition” in which any small piece 102 within the radius D centered on the small piece 102 is not blown off by pulsed air. To the state. Further, the condition (radius D) of the region to be “discharge prohibited” is defined as “condition of discharge prohibited”. In the present embodiment, it is preferable that the discharge prohibition condition (radius D) is the same as the particle size of the small piece 102. In the case of the present embodiment, since the particle size of the small piece 102 is 10 mm, the discharge inhibition condition (radius D) was also set to 10 mm. Further, supply is performed from the supply device 111 at a speed of 300 kg / h, the particle size of the small piece 102 is 10 mm, the effective width of the transfer device 101 is 0.7 m, the transfer speed is 2 m / s, and the discharge pressure of the pulse air of the separation unit 106 is 0. The test was conducted at 0.5 MPa, the nozzle diameter of the sorting unit 106 was 2 mm, and the pitch of the nozzle arrangement was 10 mm.

  Hereinafter, the influence of the pitch and thickness of the separation plate 110 will be described.

(Influence of separation plate pitch)
FIG. 4 shows the result of changing the pitch in order to investigate the influence of the pitch of the separation plate 110.

  When the pitch of the separation plate 110 is in the range of 15 mm to 20 mm, the effect of improving the overlap of the small pieces 102 described above is enhanced and the recovery rate is improved. Further, it was confirmed that the recovery rate was improved in the range of the separation plate 110 in the range of 10 mm to 30 mm as compared with the case where the separation plate 110 was not provided. Further, when the pitch was smaller than 10 mm, the pitch was 10 mm smaller than the particle size of the small pieces 102, so that clogging occurred and the recovery rate was greatly reduced.

(Influence of separation plate thickness)
FIG. 5 shows the result of changing the thickness T (defined in FIG. 2) of the separation plate 110 in order to investigate the influence of the thickness T of the separation plate 110. The separation plate pitch was 15 mm, and the discharge inhibition condition was 10 mm.

  From the graph, it was found that the range of the thickness T of the separation plate 110 is preferably 0.3 mm to 4 mm. If it is less than 0.3 mm, it is difficult to process and it is considered that the durability is difficult. On the other hand, when the thickness exceeds 4 mm, the phenomenon that the small piece 102 supplied from the supply device 111 is placed on the separation plate 110 occurs, and the sorting accuracy deteriorates.

  In the case of the present embodiment, the separation plate 110 does not exist in the area where the identification device 105 determines the plastic material of the small piece 102, and therefore the reflection of the separation plate 110 does not affect the determination. Therefore, in this embodiment, an identification device for near-infrared discrimination using a polygon scanner or a galvanometer mirror is used.

  In addition, regarding the method of supplying the plurality of small pieces 102 to the separation plate 110, not only the case where the small pieces 102 are supplied so as to drop from the upper side of the separation plate 110, but also the separation plate 110 is arranged in the intermediate portion of the transport device 101. The small piece 102 may be supplied to the conveying device 101 upstream of the separation plate 110.

  According to the present invention, it is possible to determine the type of plastic from a mixture of small pieces made of plastic and a plurality of small pieces of plastic material, in particular, from a mixture of small pieces crushed for recycling from waste home appliances. It is possible to sort well.

DESCRIPTION OF SYMBOLS 101 Conveying device 102 Small piece 103 Light source 104 Light receiving element 105 Identification device 106 Sorting unit 107 Partition plate 108 Diagonal chute 109 Partition rail 110 Separation plate 111 Feed device 112 Fixing means

Claims (3)

A supply device for continuously supplying a plurality of plastic pieces;
A transport device for transporting the supplied small piece in one direction;
An identification device for identifying the plastic material of the small piece on the conveying device;
A sorting device including a sorting unit for sorting small pieces of a specific plastic material from among the plurality of pieces based on the identification result of the identification device;
A plate-shaped separation plate that is arranged upstream of the identification device and above the identification device in the conveyance direction of the conveyance device, extends along the conveyance direction, and is arranged in a direction perpendicular to the conveyance direction. With
A sorting apparatus in which the arrangement pitch of the separation plates is selected from a range of 1 to 3 times the diameter of the circumscribed circle of the small piece. 2. The sorting apparatus according to claim 1, wherein a pitch of the separation plate is selected from a range of 1.5 to 2 times a diameter of a circumscribed circle of the small piece. The sorting device according to claim 1 or 2, wherein a thickness of the separation plate in the width direction of the transport device is selected from a range of 0.3 mm to 4 mm.