JP2013238524A - Sorting method and sorting system of plastic inclusion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic material sorting system capable of sorting and collecting transparent plastic from plastic inclusion.SOLUTION: The plastic inclusion sorting method includes illuminating plastic inclusion 1 conveyed on a belt conveyer 4 with a beam of light including a near infrared region and detecting reflected light 6 with a near infrared detection device 7 to discriminate specific material from plastic inclusion. A reflection powder 14 is uniformly splayed over the belt conveyer before loading plastic inclusion on the belt conveyer, and the plastic inclusion is loaded on the reflection powder splayed over the belt conveyer. Dispersing mechanisms 16, 3 and 15 replenish the reflection powder to maintain the reflection powder at a constant level on the belt conveyer. Transparent plastic is discriminated and sorted as specific material from among the plastic inclusion.

Description

  The present invention relates to a sorting method and a sorting apparatus for sorting a specific plastic from a sorting object in which plastic pieces are mixed for the purpose of recycling used household electrical appliances.

  Recent mass production, mass consumption, and mass disposal economic activities have caused global environmental problems such as global warming and resource depletion. Under such circumstances, in Japan, the Home Appliance Recycling Law was fully enforced in April 2001 to build a recycling-oriented society. Recycling used air conditioners, TVs, refrigerators, freezers, and washing machines Is required.

  Patent Document 1 proposes a method related to automatic plastic material sorting.

  In FIG. 7, the block diagram of the conventional plastic material separation apparatus 100 is shown.

  The plastic mixture 102 flowing on the belt conveyor 101 is irradiated with light including near infrared rays from the light source 103, and the material identification device 104 receives the reflected light of the plastic mixture 102 to individually identify the material. A plurality of air nozzles 106 arranged behind the belt conveyor 101 discharge pulse air from the specific nozzles for a certain period of time, so that the plastic 105 of a specific material among the materials identified by the material identification device 104 is removed. Separate from plastic mixture 102.

  In the near-infrared region, since there is a different absorption characteristic for each plastic, the material can be identified by comparing with pre-registered waveform data. Because identification objects can be separated from mixed substances by pulsed air, even plastic materials with similar compositions such as polypropylene (hereinafter referred to as PP), polystyrene (hereinafter referred to as PS) and acrylonitrile butadiene styrene (hereinafter referred to as ABS), which are generated in large quantities at recycling plants, are separated. Is possible.

  In this configuration, in order to prevent plastic from adhering to the belt conveyor due to the influence of static electricity and adversely affecting the plastic flight trajectory when blown off with pulsed air in the subsequent process, carbon is kneaded as the material of the belt conveyor. However, a black rubber material with good conductivity is used.

Japanese translation of PCT publication No. 2002-540397

  However, the conventional plastic material separation apparatus has a problem that the transparent plastic cannot be separated and collected from the plastic mixture.

  That is, in the conventional plastic material sorting apparatus, the belt conveyor is black due to the influence of carbon or the like, and is in a state in which it is difficult to reflect near infrared rays. Since the transparent plastic has no surface reflection, the same reflected light as that of the belt conveyor is detected for the transparent plastic on the belt conveyor. For this reason, transparent plastics could not be identified and could not be collected separately from the plastic mixture.

  In view of the above-described conventional problems, an object of the present invention is to provide a plastic mixture separation method and a separation apparatus that enable separation and collection of transparent plastics and improve the recycling rate.

In order to solve the above-described problem, the first aspect of the present invention provides:
A plastic material conveyed by a belt conveyor is illuminated with illumination including a near infrared region, and a reflected light is detected by a near infrared detector to identify a specific material from the plastic mixture, and the belt conveyor A plastic mixture separation method for separating the specific material from the plastic mixture by discharging pulsed air from a pulse air nozzle array arranged in a flight path of the plastic mixture discharged while flying from the unloading end In
Before the plastic mixture is placed on the belt conveyor, the powder reflector is spread evenly on the belt conveyor,
Place the plastic mixture on the powder reflector dispersed on the belt conveyor,
Replenish so that the powder reflector on the belt conveyor is kept constant by a dispersion mechanism,
The method for separating plastic mixture, wherein the transparent plastic in the plastic mixture is separated as the specific material.

The second aspect of the present invention
The transparent plastic is acrylonitrile butadiene styrene or polystyrene according to the first aspect of the present invention.

The third aspect of the present invention
The powder reflecting material is a method for separating a plastic mixture according to the first or second aspect of the present invention, wherein the powder reflecting material is polyurethane.

The fourth aspect of the present invention is
The dispersion mechanism is
A powder reflector supply unit for supplying the powder reflector;
The plastic mixture is uniformly placed so that the plastic mixture materials do not overlap each other, and the plastic mixture is placed on the belt conveyor, and the powder reflector supplied from the powder reflector supply unit is placed on the belt conveyor. A vibration feeder to spray,
The method for separating plastic mixture according to any one of the first to third aspects of the present invention, further comprising: a brush that is dispersed on the belt conveyor and disperses the powder reflection material in a certain thickness. .

The fifth aspect of the present invention provides
The powder reflector is replenished on the belt conveyor being transported by attaching the powder reflector to the plastic mixture before being supplied to the belt conveyor. A fourth method of the present invention for separating plastic inclusions.

The sixth aspect of the present invention provides
There are teaching data of opaque plastic, teaching data of the powder reflector, and teaching data of the transparent plastic on the powder reflector, and on the powder reflector according to the amount of the powder reflector on the belt conveyor. The method for separating plastic mixture according to the first aspect of the present invention is characterized in that the transparent plastic teaching data is dynamically changed to identify and sort the transparent plastic.

The seventh aspect of the present invention
A material hopper that supplies plastic mixture;
A vibration feeder for making the plastic mixture materials supplied from the material hopper uniform so as not to overlap each other;
A powder reflector supply unit for supplying a powder reflector to the vibration feeder;
After the powder reflector is dispersed from the vibration feeder, a belt conveyor that conveys the plastic mixture placed from the vibration feeder;
A brush for dispersing the powder reflector on the belt conveyor to a certain thickness;
A light source for illuminating illumination including a near infrared region on the plastic mixture conveyed by the belt conveyor;
A detector for detecting far-infrared reflected light from the plastic mixture;
An identification unit for identifying a specific material from the plastic mixture according to the detection result of the detector;
A pulse air nozzle array that is disposed in a flight path of the plastic mixture discharged while flying from the carry-out end of the belt conveyor, discharges pulsed air, and separates the transparent plastic as the specific material from the plastic mixture; With
The powder reflector is supplied from the powder reflector supply unit to the vibration feeder, and the supplied powder reflector is sprayed from the vibration supplier onto the belt conveyor, and then the plastic mixture is removed from the material hopper. The plastic mixture is supplied to the vibration feeder, and the supplied plastic mixture is placed on the belt conveyor on which the powder reflector is dispersed from the vibration feeder. It is.

  By using the present invention, it is an object to provide a separation method and a separation apparatus for plastic inclusions that enable separation and collection of transparent plastics and improve the recycling rate.

Configuration diagram of plastic sorting apparatus according to Embodiment 1 of the present invention (A) The figure which shows the plastics of the state which has not adhered polyurethane of Embodiment 1 of this invention, (b) The figure which shows the plastics of the state of having adhered polyurethane of Embodiment 1 of this invention (A) A schematic graph showing the concept of the relationship between reflected light and wavelength when measuring the reflected light of a white PS against the background of a belt conveyor, and a schematic side view showing the reflected state from the white PS, (b) ) A schematic graph showing the concept of the relationship between reflected light and wavelength when measuring the reflected light of a transparent PS against a background of a belt conveyor, and a schematic side view showing the reflected state from the transparent PS, (c) book The concept of the relationship between reflected light and wavelength when a transparent PS is placed on a belt conveyor in which an appropriate amount of polyurethane powder according to Embodiment 1 of the invention is dispersed and the reflected light is measured with the transparent PS as the background of the belt conveyor. Schematic side view showing the state of reflection from the schematic graph and transparent PS (A) The figure which showed the relationship between the reflected light and wavelength in each plastic before correction | amendment in Embodiment 1 of this invention, (b) Each plastic after correction | amendment in Embodiment 1 of this invention The figure which showed the relationship between the reflected light and a wavelength in (c) The figure which showed the relationship between the absorption coefficient of a polyurethane, and a wavelength, (d) In Embodiment 1 of this invention, the comparison before and after performing a correction calculation was performed. Figure showing the results The figure which shows the determination step which considered the response | compatibility to the adhesion amount change of polyurethane of Embodiment 1 of this invention, and the application to a translucent material The image figure which shows the range of PS plastic group of Embodiment 1 of this invention Configuration diagram of a conventional plastic material sorting device

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a configuration diagram of a plastic sorting apparatus according to Embodiment 1 of the present invention.

  The plastic 1 in which a plurality of types are mixed is supplied to the material hopper 2 from the previous process and stored for a certain amount, and is then loosened by the vibration feeder 3 so that the materials do not overlap with each other and supplied to the belt conveyor 4. Is done.

  With this configuration, the production amount is controlled by making the distribution state of the plastic 1 existing on the belt conveyor 4 and the dispersion state in the width direction constant.

  In addition, the plastic sorting apparatus according to the first embodiment has a light source 5 that irradiates light including a near-infrared region and a reflection reflected from the plastic 1 with respect to the plastic 1 that is supplied to the belt conveyor 4 and includes a plurality of types. A light receiving element 7 that detects the light 6, an identification device 8 that acquires a signal of the reflected light 6 detected by the light receiving element 7 and identifies the material, a sorting unit 9 having a plurality of pulse air nozzles, and a partition plate 10 The separated residue zone 11 and recovery zone 12, and the control device 13 are provided.

  The light receiving element 7 corresponds to an example of the detector of the present invention. The identification device 8 corresponds to an example of an identification unit of the present invention. Moreover, the several pulse air nozzle which the classification | category unit 9 has corresponds to an example of the pulse air nozzle row | line | column of this invention.

  The control device 13 has a program set so as to blow off and collect only a predetermined substance, and the substance data sent from the identification device 8 and the position speed information and / or time management information of the belt conveyor 4 are collected. The specific plastic is blown off to the collection zone 12 by sending a blow-off command to the separation unit 9 at a predetermined timing.

  In continuous processing, it is preferable to install the separation unit 9 at a position 100 mm away from the plastic 1 discharged from the discharge end of the belt conveyor 4.

  The normal trajectory of the plastic 1 falls in an arc and is collected in the residue zone 11. Separation of specific plastics from multiple types of plastics 1 by installing a partition plate 10 between the position where the plastics 1 do not interfere with the normal trajectory and the plastics 1 trajectory by pulsed air injected from the sorting unit 9 It can be recovered.

  For example, by injecting pulsed air only to PS, only PS can be collected separately from a plurality of types of plastic 1.

  A powdery polyurethane 14 exists as a reflector on the belt conveyor 4, and a brush 15 is provided as a reflector dispersion function so that the polyurethane 14 is uniform and below a certain amount on the belt conveyor 4. ing.

  Further, in the initial state, in order to spread the polyurethane 14 on the belt conveyor 4, a polyurethane box 16 for storing the polyurethane 14 is installed in the material hopper 2, and is sprayed by the control device 13 at an arbitrary timing. Is possible.

  The polyurethane box 16 corresponds to an example of the powder reflector supply unit of the present invention.

  First, a method for supplying and maintaining the amount of polyurethane 14 on the belt conveyor 4 will be described.

  In the refrigerator, polyurethane is used as a heat insulating material, and when the refrigerator is broken and decomposed in home appliance recycling, it is possible to collect the powdered polyurethane. Therefore, it does not take time to obtain the polyurethane used as the reflector material in the recycling factory.

  In the initial state of the plastic sorting apparatus according to the first embodiment, there is no polyurethane 14 on the belt conveyor 4, so it is necessary to supply a certain amount. Therefore, the polyurethane 14 generated and collected at the recycling factory is put in the polyurethane box 16 in the material hopper 2, and the material hopper 2, the vibration feeder 3 and the belt conveyor 4 are operated, and the polyurethane 14 powder in the polyurethane box 16 is operated. Is placed on the belt conveyor 4 to obtain an initial state for the plastic sorting operation.

  The polyurethane 14 powder tends to adhere to the surface due to the inherent flexibility of the rubber of the belt conveyor 4. Further, polyurethane 14 powder further adheres to the polyurethane powder adhering to the surface of the belt conveyor 4 due to the influence of electrostatic force.

  When the polyurethane 14 powder is sowed, the spraying state of the polyurethane 14 on the belt conveyor 4 is monitored by the identification device 8, and the control device 13 performs an appropriate amount of control.

  As described above, as the initial state for the plastic sorting operation, after starting the sorting and collecting operation of the specific material from the mixed plastic 1, the belt 1 is supplied with the polyurethane 14 attached to the plastic 1 in advance. The shortage of the polyurethane 14 on the conveyor 4 is prevented. Further, the physical force of the brush 15 prevents a certain amount or more of the polyurethane 14 from adhering to the belt conveyor 4, and the identification device 8 monitors the adhesion amount of the polyurethane 14 on the belt conveyor 4 to check the adhesion state. By visualizing and instructing the operator to clean, the amount of polyurethane 14 on the belt conveyor 4 is maintained at a constant amount.

  FIG. 2A shows the plastic 1 in a state where the polyurethane 14 is not attached, and FIG. 2B shows the plastic 1 in a state where the polyurethane 14 is attached.

  When the mixed plastic 1 is supplied to the material hopper 2, the polyurethane 14 may adhere to the mixed plastic 1. However, in the plastic sorting apparatus according to the first embodiment, the polyurethane box 16 in the material hopper 2. Then, the polyurethane 14 is supplied to the mixed plastic 1, and the polyurethane 14 is adhered to the mixed plastic 1 as shown in FIG.

  In the adhesion state, the adhesion density per unit area is about 5% to 50%. When the adhesion amount is small, the polyurethane 14 on the belt conveyor 4 is reduced, and when the adhesion density is increased, the polyurethane 14 is excessively adhered.

  On the other hand, the appropriate amount of polyurethane 14 on the belt conveyor 4 is about 0.05 mm to 0.5 mm on the belt conveyor 4, and is not only removed by the brush 15 but also removed by the operator. To keep a certain amount. Further, a suction device may be provided together with the brush 15, and the polyurethane 14 may be maintained at an appropriate amount by periodically sucking it.

  The polyurethane 14 having an average particle diameter of about 0.05 mm is used, and when it adheres to the belt conveyor 4, it has the above thickness. When the adhesion density of the polyurethane 14 on the belt conveyor 4 is about 50% or more, the reflected light 6 becomes about 1/10 of the maximum reflected light, and detection is possible. At an adhesion density lower than that, there is reflected light, but there is a variation in measurement and the separation is not stable.

  Further, when the thickness on the belt conveyor 4 is 0.5 mm or more, the mixed plastic 1 is easily slipped on the belt conveyor 4, and a deviation occurs between the identification position and the blow-off position, and the separation ability is lowered.

  Next, the operation for identifying plastic will be described.

  Basically, the fact that the absorption characteristics in the near-infrared region of the plastic 1 are different when the molecular structure is different is utilized. A light receiving element 7 for detecting reflected light 6 reflected from the plastic 1 by irradiation of light including a near infrared region from the light source 5 is provided, and a calculation obtained from a signal output detected by the light receiving element 7 and a signal output registered in advance. It is possible to determine the plastic 1 by comparing the value.

  FIGS. 3A to 3C are conceptual diagrams of reflected light from plastic. The schematic side view which shows the reflection state from a plastic, respectively, and the schematic graph which shows the concept of the relationship between reflected light and a wavelength are shown.

  FIG. 3A shows a schematic side view and the concept of the relationship between the reflected light and the wavelength when the white PS 21 is measured with the light receiving element 7 against the background of the belt conveyor 4.

  The relationship between the reflected light from the plastic and the wavelength at that time is indicated by a solid line, and the portion where the plastic does not exist, that is, the relationship between the reflected light from the belt conveyor 4 and the wavelength at that time is indicated by a broken line. Similarly in FIGS. 3B and 3C, the relationship between the reflected light and the wavelength at that time is indicated by a solid line and a broken line.

  Due to the characteristics of the white PS21, only a specific wavelength is absorbed, and reflected light is detected at other wavelengths. The most characteristic specific wavelength is 1.68 μm, and reflected light as shown in the schematic graph of FIG. 3A is detected, and almost no reflected light is measured from the belt conveyor 4.

  FIG. 3B shows a schematic side view and the concept of the relationship between the reflected light and the wavelength when the reflected light of the transparent PS 22 is measured by the light receiving element 7 against the background of the belt conveyor 4.

  Since the transparent PS 22 has almost no reflection on the surface, the reflected light from the transparent PS 22 is only the brightness of the reflected light of the belt conveyor 4 even in the wavelength band where there is no absorption due to the plastic characteristics, and the contrast difference indicating the characteristics of the plastic Cannot detect the reflected light.

  In FIG. 3C, the transparent PS 22 transported by the belt conveyor 4 having the configuration of the first embodiment, that is, the transparent PS 22 placed on the belt conveyor 4 after a suitable amount of powder of polyurethane 14 is dispersed, The schematic side view and the concept of the relationship between the reflected light and the wavelength when the reflected light is measured by the light receiving element 7 against the background of the conveyor 4 are shown.

  Reflection occurs when the polyurethane 14 is dispersed, and the belt conveyor 4 has the effect of becoming brighter. When the transparent PS 22 is placed there, the surface reflection is the same as when the polyurethane 14 is not present, but the reflection is reflected on the back surface of the transparent PS 22. In order to generate, the reflected light plus the characteristics of both PS and polyurethane 14 is measured.

  Since the reflected light of the transparent PS 22 measured on the belt conveyor 4 with the polyurethane 14 also takes into account the absorption specification of the polyurethane 14, it is necessary to exclude the influence of the polyurethane 14.

  When the input light is Lin (f) (f indicates the wavelength and all wavelengths are intended by (f)), and the reflected light is Lout_object (f), the object (in the case of PS) Can be expressed by (Equation 1).

(Equation 1)
Lout_PS (f) = Lin (f) ×
(Surface reflection absorption characteristics_PS (f) +
(Internal absorption characteristics_PS (f) × thickness) × (absorption characteristics_polyurethane (f) × thickness))

In (Equation 1), white PS is approximated by (Equation 2) because most of the reflected light is surface reflection because the reflected light does not change regardless of the amount of polyurethane.

(Equation 2)
Lout_PS white (f) = Lin (f) × surface reflection absorption characteristic_PS white (f)

On the other hand, since the transparent PS 22 has almost no surface reflection, it is approximated by (Equation 3).

(Equation 3)
Lout_Transparent PS_Urethane (f) = Lin (f) ×
(Internal absorption characteristics_PSc (f) × thickness) × (absorption characteristics_polyurethane (f) × thickness))
When (Equation 3) is transformed, the characteristic can be expressed by (Equation 4).

(Equation 4)
Lout_transparent PS_on urethane (f) / (absorption characteristics_polyurethane (f) x thickness)
= Lin (f) x (internal absorption characteristics_PSc (f) x thickness)

Therefore, the result of measuring three reflected light data of reflected light of white PS21, reflected light when transparent PS22 is placed on polyurethane 14 and reflected light of white ABS, and (Equation 4) were used. The results of examining the influence of the correction calculation are shown in FIGS. 4 (a) to 4 (d). This time, the polyurethane 14 was evaluated with a thickness of about 0.2 mm.

  4A shows the relationship between the reflected light and the wavelength before correction, and FIG. 4B shows the relationship between the reflected light and the wavelength after correction according to (Equation 4). FIG. 4C shows the relationship between the absorption coefficient and wavelength of the polyurethane 14, and FIG. 4D shows the result of comparison before and after correction.

  In addition, the numerical value shown on the vertical axis | shaft of Fig.4 (a) and FIG.4 (b) has shown the value after AD-converting reflected light by specific magnification. Moreover, the numerical value shown on the horizontal axis of Fig.4 (a)-FIG.4 (c) has shown the channel number of the measured sensor. The detection wavelengths of the sensors of the respective channels are as shown in Table 1, and the sensors of the respective channels whose detection wavelengths are every 0.05 μm are arranged at almost equal intervals, so that FIG. 4 (a) to FIG. 4 (c) The horizontal axis of) accurately represents the change in wavelength. The sensor of channel 7 is a sensor that detects a wavelength of 1.68 μm.

  In the comparison method before and after correction, reflected light was standardized, and the degree of coincidence was calculated by the sum of squared differences.

  The difference sum of squares is zero, and the value increases as the difference increases.

  As shown in FIG. 4D, the degree of coincidence between the white PS 21 and the transparent PS 22 is about 0.7 before the correction, and the degree of coincidence between the white PS 21 and the white ABS is larger than 0.6. The reflected light when placed on the polyurethane 14 cannot be determined to be the same as the white PS 21 as it is. By performing the correction calculation according to (Equation 4), the degree of coincidence between the white PS21 and the transparent PS22 is about 0.3, which is smaller than the difference between the white ABS, so that the transparent PS22 can be determined to be the same as the white PS21. Become. Therefore, the approximation by (Equation 4) with a predetermined amount of polyurethane is considered reasonable.

  FIG. 5 shows a determination step that expands the application range of this principle, considers the change in the adhesion amount of polyurethane, and applies to a translucent material.

  In step S1, the reflected light of the plastic mixture on the belt conveyor 4 and the reflected light of the surface of the belt conveyor 4 on which the polyurethane 14 is dispersed and no plastic mixture exists are acquired. Then, the degree of coincidence is measured with the teaching data of polyurethane for the reflected light taken in, and it is determined whether it is a belt conveyor 4 or a plastic mixture. Here, the data determined as the belt conveyor 4 is referred to as conveyor data.

  This is processing when it is determined that step S2 is the belt conveyor 4.

  In the case of the belt conveyor 4, when the adhesion of the polyurethane 14 increases, the overall brightness increases. Therefore, an average value of all wavelengths is calculated and used for calculating the adhesion amount of the polyurethane 14 to calculate the thickness.

  On the other hand, since the coincidence determination of the polyurethane 14 is performed after standardization, it can be sorted without being affected by the brightness.

  Further, since the spraying amount of the polyurethane 14 is not always constant depending on the location, the belt conveyor 4 is divided in the x direction and the y direction, and the spraying amount in fine units is measured.

  The belt conveyor 4 used this time has a width of 1400 mm and a circumference of 10,000 mm. The division direction and the number of divisions are measured by dividing the width direction of the belt conveyor 4 in the x direction by dividing 1400 mm into 140 by 10 mm width. Moreover, the circumference direction of the belt conveyor 4 is set to the y direction, and it is divided into 10 and measured at a length of 1000 mm. Since the change in the circumferential direction is small, the number of divisions is reduced.

  Under the plastic mixture, the dispersion amount of the polyurethane 14 cannot be measured, but the abundance ratio of the plastic mixture on the belt conveyor 4 is about 10%, and the data of the polyurethane 14 is always obtained during the sorting operation. The effects of plastic inclusions can be excluded.

  Next, a method for creating teaching data shown in step S3 will be described.

  The teaching data is created using the belt conveyor 4 to which a certain amount of polyurethane 14 is attached, the white PS, and the transparent PS on the polyurethane having a specific thickness.

  The teaching data of the transparent PS used for teaching is created using the transparent PS having the greatest thickness among the transparent PSs to be sorted. Further, the teaching data of the transparent PS is created based on (Expression 4), excluding the polyurethane characteristic having a specific thickness.

  In step S4, the teaching data of the transparent PS is corrected.

  The teaching data of the transparent PS is created based on (Equation 3). Therefore, there is a deviation from the actual measurement value in which the thickness of the polyurethane 14 is changed. Therefore, the teaching data is corrected using the data of the reflected light based on the polyurethane thickness acquired in step S2.

  Specifically, the initial transparent PS teaching data is divided by the initial polyurethane data. After that, the polyurethane data whose thickness has changed is multiplied. Further, correction data for surface reflection is calculated.

  From the above calculation, teaching data corresponding to the thickness of the polyurethane 14 is created.

  The teaching data may be created every time the amount of polyurethane is acquired, but this time, instead of every time it is acquired, when a brightness change of 1/10 of the acquired maximum reflected light occurs. The correction of teaching data is being implemented.

  In step S4, the process of correcting and creating the teaching data of the transparent PS according to the change in the thickness of the polyurethane 14 is the teaching data of the transparent plastic according to the abundance of the powder reflector on the conveyor of the present invention. This is an example of an operation that dynamically changes.

  In step S5, the degree of coincidence is calculated.

  In step S1, the degree of coincidence between standardization and conveyor data is calculated. In step S5, the degree of coincidence with the taught plastic data is calculated.

  Standardization and coincidence calculation in step S5 are the same as in step S1.

  In standardization, after performing offset and inclination correction for each reflected position with respect to the reflected light, the average value in the wavelength direction and the standard deviation data are acquired, calculated by (Equation 5), and the sum of squared differences from the teaching data The degree of coincidence is calculated by

(Equation 5)
Standardized value (wavelength) = (reflected light (wavelength)-average value) / standard deviation

The degree of coincidence may be calculated using a calculation based on the Mahalanobis distance. At that time, weighting at each wavelength may be considered.

  The mixed plastic from waste home appliances mainly includes PP and ABS in addition to PS, and in this step S5, the degree of coincidence is calculated for all these plastics.

  In the coincidence calculation, it is determined that the material of the teaching data having the lowest coincidence is the corresponding material. However, if the coincidence does not become a predetermined threshold value or less, a process of “not applicable” is performed.

  In step S6, determination calculations such as white PS and transparent PS are performed.

  The white PS and the transparent PS can be determined by calculating individual matching degrees, but there are also translucent materials, and the translucent PS exhibits characteristics between the white PS and the transparent PS.

  Therefore, a plastic PS in which a white PS material, a transparent PS material, and a translucent PS material are present is determined as a PS plastic group.

  Finally, in step 7, based on the determination result in step S6, only the target of the corresponding characteristic is blown off, and the separation from the mixed plastic is completed.

  Next, the identification method of the PS plastic group in step S6 will be described in detail with reference to FIG.

  FIG. 6 is an image diagram showing the range of the PS plastic group.

  A translucent PS has a characteristic between white PS and transparent PS according to (Equation 1), but does not completely match white PS or transparent PS, and is subtle due to differences in transparency and thickness. Show different characteristics.

  Therefore, the degree of coincidence between the detected plastic data and the white PS is A, the degree of coincidence between the detected plastic data and the transparent PS is B, the degree of coincidence between the teaching data of the white PS and the transparent PS is C, When the threshold value for white PS is D and the threshold value for transparent PS is E, the translucent PS between white and transparent is determined to be PS when the relationship of (Equation 6) is satisfied. They are identified as plastic groups.

(Equation 6)
A + B <C + D + E

As shown in FIG. 6, the relationship shown in (Equation 6) is such that the portion between the white PS and the transparent PS is wrapped in an area modeled on an elliptical equation, and the parts in that area are the same PS plastic. They are identified as a group.

  Although the first embodiment has been described by taking PS as an example, the same processing as in the first embodiment can be applied to an ABS having a transparent one.

  As described above, in the first embodiment, the reflective material is interposed between the belt conveyor and the plastic mixture, so that the light from the light source is reflected, and the separate collection is possible even in the transparent plastic. As a result, the recycling rate can be improved.

  By using the plastic mixture separation method and the separation apparatus of the present invention, it becomes possible to separate the transparent plastic material, which has been difficult in the past, and to recycle the transparent plastic material. The plastic mixture separation method and separation apparatus of the present invention can be widely used as a separation method for recycling specific materials contained in waste home appliances and general waste.

  The plastic mixture separation method and plastic mixture separation device according to the present invention enables separation and collection of transparent plastics, has the effect of improving the recycling rate, and aims to recycle used household electrical appliances. In addition, the present invention is useful as a sorting method and a sorting device for sorting a specific plastic from a sorting object in which plastic pieces are mixed.

DESCRIPTION OF SYMBOLS 1 Plastic 2 Material hopper 3 Vibration supply machine 4 Belt conveyor 5 Light source 6 Reflected light 7 Light receiving element 8 Identification device 9 Sorting unit 10 Partition plate 11 Residual zone 12 Collection zone 13 Control device 14 Polyurethane 15 Brush 16 Polyurethane box 21 White PS
22 Transparent PS
DESCRIPTION OF SYMBOLS 100 Conventional plastic material separation apparatus 101 Belt conveyor 102 Plastic mixture 103 Light source 104 Material identification apparatus 105 Plastic of specific material 106 Air nozzle

Claims (7)

A plastic material conveyed by a belt conveyor is illuminated with illumination including a near infrared region, and a reflected light is detected by a near infrared detector to identify a specific material from the plastic mixture, and the belt conveyor A plastic mixture separation method for separating the specific material from the plastic mixture by discharging pulsed air from a pulse air nozzle array arranged in a flight path of the plastic mixture discharged while flying from the unloading end In
Before the plastic mixture is placed on the belt conveyor, the powder reflector is spread evenly on the belt conveyor,
Place the plastic mixture on the powder reflector dispersed on the belt conveyor,
Replenish so that the powder reflector on the belt conveyor is kept constant by a dispersion mechanism,
A method for separating plastic mixture, wherein the transparent plastic in the plastic mixture is separated as the specific material.   The method for separating a plastic mixture according to claim 1, wherein the transparent plastic is acrylonitrile butadiene styrene or polystyrene.   The method for separating a plastic mixture according to claim 1, wherein the powder reflector is polyurethane. The dispersion mechanism is
A powder reflector supply unit for supplying the powder reflector;
The plastic mixture is uniformly placed so that the plastic mixture materials do not overlap each other, and the plastic mixture is placed on the belt conveyor, and the powder reflector supplied from the powder reflector supply unit is placed on the belt conveyor. A vibration feeder to spray,
The method for separating a plastic mixture according to any one of claims 1 to 3, further comprising a brush that is dispersed on the belt conveyor and disperses the powder reflection material in a certain thickness.   2. The powder reflector is replenished on the belt conveyor being transported by attaching the powder reflector to the plastic mixture before being supplied to the belt conveyor. The method for separating a plastic mixture according to any one of -4.   There are teaching data of opaque plastic, teaching data of the powder reflector, and teaching data of the transparent plastic on the powder reflector, and on the powder reflector according to the amount of the powder reflector on the belt conveyor. 2. The plastic mixture sorting method according to claim 1, wherein the teaching data of the transparent plastic is dynamically changed to identify and sort the transparent plastic. A material hopper that supplies plastic mixture;
A vibration feeder for making the plastic mixture materials supplied from the material hopper uniform so as not to overlap each other;
A powder reflector supply unit for supplying a powder reflector to the vibration feeder;
After the powder reflector is dispersed from the vibration feeder, a belt conveyor that conveys the plastic mixture placed from the vibration feeder;
A brush for dispersing the powder reflector on the belt conveyor to a certain thickness;
A light source for illuminating illumination including a near infrared region on the plastic mixture conveyed by the belt conveyor;
A detector for detecting far-infrared reflected light from the plastic mixture;
An identification unit for identifying a specific material from the plastic mixture according to the detection result of the detector;
A pulse air nozzle array that is disposed in a flight path of the plastic mixture discharged while flying from the carry-out end of the belt conveyor, discharges pulsed air, and separates the transparent plastic as the specific material from the plastic mixture; With
The powder reflector is supplied from the powder reflector supply unit to the vibration feeder, and the supplied powder reflector is sprayed from the vibration supplier onto the belt conveyor, and then the plastic mixture is removed from the material hopper. The plastic mixture is supplied to the vibration feeder, and the supplied plastic mixture is placed on the belt conveyor on which the powder reflector is dispersed from the vibration feeder. .