JP2009226248A - Plastic pellet sorting machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic pellet sorting machine capable of detecting discolored pellets, pellets in which foreign matters are mixed and deformed pellets by backscattered light from plastic pellets and accurately removing the pellets. <P>SOLUTION: In the plastic pellet sorting machine, by arranging a line sensor camera provided with a light source and a line sensor unit so as to be a pair on both sides of the falling plastic pellets 21 and measuring the backscattered light of irradiation light from the light source, the foreign matter, black color and deformation of the plastic pellets 21 are detected and the non-defective products and defective products of the plastic pellets 21 are sorted. A pair of fluorescent lamps 23 are disposed in the vertical direction of the falling plastic pellets 21 as the light source, each of the pair of fluorescent lamps 23 is provided with a shielding cylindrical body 24, a cylindrical lens 25 is disposed to the window 24A of the shielding cylindrical body 24, and the falling plastic pellets 21 are irradiated with light from the cylindrical lens 25. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plastic pellet sorter, and more particularly to a plastic pellet sorter that can remove foreign matters, discoloration, irregularities and the like mixed in plastic (synthetic resin).

  Engineering plastics (engineering plastics and super engineering plastics) as an alternative material for metals have come into common use.

  With the generalization of this engineering plastic, applications are expanding in various fields such as automobiles, home appliances, OA equipment, medical equipment, and electronic equipment.

  For these reasons, quality control of engineering plastics has been required.

  With the advent of the era of engineering plastics, it has become important to remove foreign substances, discoloration, and deformed plastics mixed in engineering plastic pellets.

  These various foreign matters are mixed during resin production, conveyance process, molding process, recycling (spool runner), and other stages.

  Hereinafter, the mixing of foreign matters will be described in detail.

  Foreign materials mixed into plastic pellets are broadly classified into foreign materials (dust, residue of pipeline switching valve, residue remaining at joints of transfer pipes, etc.) and foreign materials that have been altered by burning. .

  The problems that come from the raw materials are mainly discoloration that occurs in the heat treatment process of the extruder, and deposits that are generated in the T-die during the extrusion process (eyes, die flowers).

  Even in the resin manufacturing process, efforts to prevent further discoloration, burnt (yellowing), contamination of eyes, etc. are required.

  In addition, there is a danger that the large discoloration point may be further crushed in the molding machine and dispersed to the small discoloration point to enlarge the defect.

  Further, as a conventional technique, there is a color sorter that sorts defective products such as grains proposed by the present inventors (see Patent Document 1 below).

Furthermore, a resin pellet colored particle removing apparatus and apparatus and a pellet sorter (see Patent Documents 2 and 3 below) have been proposed.
JP 2003-156447 A Japanese Patent Laid-Open No. 2-253891 JP 2006-026469 A

  As mentioned above, improving the quality of engineering plastic pellets has become essential.

  Therefore, utilizing the know-how of the color sorter in the US industry that has been accumulated so far, we added various devices suitable for plastic pellets to sort plastic pellets at a minimum cost.

  In view of the above situation, the present invention provides a plastic pellet sorter that can detect discolored pellets, foreign matter-contaminated pellets, and irregular-shaped pellets by backscattered light from plastic pellets and accurately remove these pellets. The purpose is to do.

In order to achieve the above object, the present invention provides
[1] A line sensor camera provided with a light source and a line sensor device is arranged on both sides of the falling plastic pellet, and the plastic pellet is measured by measuring the back scattered light of the irradiation light from the light source. A plastic pellet sorter that detects foreign matter, discoloration, and deformation of the plastic pellets and sorts the plastic pellets into non-defective products and defective products, and a pair of fluorescent lamps are arranged as the light source in the vertical direction of the falling plastic pellet Each of the pair of fluorescent lamps includes a shielding cylinder, and a cylindrical lens is disposed in a window of the shielding cylinder, and the falling plastic pellet is irradiated with light from the cylindrical lens.

  [2] In the plastic pellet sorting machine according to [1], the reflected light from the falling plastic pellet is transmitted rearward through a cylindrical lens disposed between the pair of fluorescent lamps through a dustproof window. It detects by the line sensor apparatus arrange | positioned, It is characterized by the above-mentioned.

[3] The plastic pellet sorting machine according to [2], wherein the line sensor device includes a wide-angle lens, a color glass filter, and a line sensor from a cylindrical lens side disposed between the pair of fluorescent lamps. It is characterized by.
[4] In the plastic pellet sorting machine according to [1], when a defective product of the plastic pellet is detected, an air ejector is driven to blow the defective product of the plastic pellet with air and lead to a defective product path. It is characterized by.

  According to the present invention, there is provided a plastic pellet sorter capable of detecting foreign matter pellets, discoloration-mixed pellets and irregular shaped pellets by backscattered light from the plastic pellets and accurately removing these pellets.

  In the plastic pellet sorter of the present invention, a line sensor camera including a light source and a line sensor device is arranged so as to be paired on both sides of the falling plastic pellet, and the back scattered light of the irradiation light from the light source is measured. A plastic pellet sorter that detects foreign matter, discoloration, and irregularity of the plastic pellets and sorts the plastic pellets between non-defective and defective plastic pellets, and as the light source in the vertical direction of the falling plastic pellets A pair of fluorescent lamps are arranged, each of the pair of fluorescent lamps is provided with a shielding cylindrical body, a cylindrical lens is arranged in a window of the shielding cylindrical body, and light from the cylindrical lens is irradiated onto the falling plastic pellet. It is characterized by.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a schematic view of a plastic pellet sorter showing an embodiment of the present invention.

  In this figure, 2 is a hopper for storing plastic pellets 1, 3 is a vibration feeder, 4 is a roll feeder, 5 is a reference plate, 6 is a pair of line sensor cameras, 7 is a pair of light sources, 8 is an air ejector, and 9 is a good product. A route 10 is a defective product route.

  As shown in FIG. 1, the plastic pellet 1 is supplied from a hopper 2, vibrated by a vibration feeder 3, and sent to a roll feeder 4. Then, the plastic pellet 1 falls from the roll feeder 4 and passes through the reference plate 5. The dropped plastic pellet 1 is imaged by a pair of line sensor cameras 6 arranged on both sides thereof, and a non-defective product / defective product is selected.

  The sorted defective product is blown off by the air ejector 7 and discharged from the defective product path 10, and the non-defective product is taken out from the non-defective product path 9.

  Here, the pair of line sensor cameras 6 captures the backscattered light from the plastic pellet 1 to effectively use the sensitivity of the line sensor.

  Moreover, according to this plastic pellet sorter, since the irradiation light from the light source is irradiated on both sides of the falling plastic pellet 1, the entire surface of the falling plastic pellet 1 can be irradiated. Good and defective products can be accurately selected. Further, each of the pair of fluorescent lamps is provided with a shielding cylindrical body, and a cylindrical convex lens is disposed in the window of the shielding cylindrical body so that the luminous flux from the fluorescent lamp is efficiently irradiated with the focused light. Unlike the conventional irradiating method, it has the effect of increasing the pellet identification sensitivity.

  First, the light scattering property of the plastic pellet will be described.

  FIG. 2 is an explanatory view of light scattering of the plastic pellet according to the present invention.

  In this figure, 11 is a plastic pellet, 12 is an irradiation light, 13 is a backscattered light composed of a surface reflected light 13A of the plastic pellet 11 and an internal reflected light 13B of the plastic pellet 11, and 14 is a surface reflected light 14A of the plastic pellet 11. This is forward scattered light composed of the internally transmitted light 14 </ b> B of the plastic pellet 11.

  When measuring the forward scattered light 14, the internal transmitted light 14 </ b> B of the forward scattered light 14 includes information depending on the shape and color of the plastic pellet 11, but the amount of light on the side surface that passes without hitting the plastic pellet 11. The surface reflected light 14A is large, and the background noise light of the line sensor may be increased and saturated. Further, if the shape of the plastic pellet 11 is irregular, the internal transmitted light 14B hardly exists.

  On the other hand, the backscattered light 13 includes reflected light 13 </ b> A from the surface of the plastic pellet 11 and internally reflected light 13 </ b> B that is refracted and enters the inside of the plastic pellet 11. The surface reflected light 13A of the plastic pellet 11 depends on the shape of the plastic pellet 11, and the internal reflected light 13B includes information depending on the shape of the plastic pellet 11 and the color and shape of the foreign matter. Generally, the reflectance of the plastic surface reflected light 13A and the internal reflected light 13B is about 4 to 5%. The measurement of the backscattered light 13 is advantageous in that the sensitivity of the line sensor can be used effectively because there is no influence of passing light or the like.

  Due to the light scattering property of the plastic pellet as described above, the plastic pellet 11 according to the present invention is configured to capture the backscattered light 13 even if the plastic pellet 11 is a transparent body. In the method of measuring the forward scattered light 14, the passing light can be diffused by using the non-focusing action of the lens, but noise light remains.

  FIG. 3 is a block diagram of a main part of a plastic pellet sorter showing an embodiment of the present invention, FIG. 4 is a ray locus diagram of a cylindrical lens and a wide angle lens of the sorter, and FIG. 4 (b) is a top view of the light beam.

  In these figures, 21 is a falling plastic pellet, 22 is a dustproof window, 23 is a fluorescent lamp, 24 is a shielding cylinder (which may be made of aluminum) covering the fluorescent lamp 23, the inside is white or mirror-finished, and the outside is It is matte black. Reference numeral 24A denotes a window of the shielding cylindrical body 24, 25 denotes a cylindrical lens that extracts light from the fluorescent lamp, 26 denotes a cylindrical lens that transmits the reflected light from the falling plastic pellet 21, and 27 denotes a window 27A that transmits the transmitted light from the cylindrical lens 26. , 28 is a wide-angle lens that receives light that has passed through the window 27 A, 29 is a colored glass filter that receives light that has passed through the wide-angle lens 28, and 30 receives light that has passed through the colored glass filter 29. It is a line sensor.

  The conventional plastic pellet sorter has the following problems.

  (1) Most of the amount of light from the fluorescent lamp is wasted.

  (2) The fluorescent lamp light is diffusely reflected inside the device to produce background noise light in the line sensor camera, and the line sensor is saturated with the background noise light.

  (3) With a wide-angle lens, the optical path for viewing the plastic pellet is blocked by the slit and the fluorescent lamp, and the backscattered light is not captured to the maximum extent. That is, in order to obtain information from the plastic pellet, it is difficult to obtain identification information unless the backscattered light 13 shown in FIG.

  (4) Since there is a distance between the plastic pellet position and the camera lens, the angle at which the plastic pellet is viewed is small, and thus the capture rate of backscattered light is low and the true signal intensity is weak.

  (5) In the dispersion of plastic pellets by vibration of a conventional sorter, it is estimated that there are about 20 to 30 pieces per line, but it is better to make it more dense considering the number of pixels of the line sensor.

  The light emitted from the fluorescent lamp 23 is condensed and irradiated by a cylindrical lens (or a cylinder Fresnel lens) 25. A shielding cylindrical body 24 that covers the fluorescent lamp 23 is provided to suppress the generation of irregularly reflected light and increase the effective light amount.

  Further, as shown in FIG. 4A, it is understood that it is better to increase the opening angle θ of the cylindrical lens 32 so as to capture as much as possible the wide-angle backscattered light in the Y direction from the plastic pellet 31. Therefore, the cylindrical lens 32 may be a cylinder Fresnel lens that can increase the opening angle θ.

  Further, as shown in FIG. 4B, since the cylindrical lens 32 does not act in the X direction, if the image of the plastic pellet 31 is formed on the line sensor 34 by using the imaging relationship of the wide-angle lens 33. The position of the plastic pellet 31 can be detected with high accuracy.

  Since the image formation by the lens systems 32 to 33 is an elliptical pattern that is long in the Y-axis direction on the line sensor surface as shown in the image formation pattern of FIG. 4A, the pixel shape of the line sensor 34 detects the amount of light as much as possible. In order to do this, a vertically long one is good.

  FIG. 5 is an explanatory diagram for putting the plastic pellet layer width according to the present invention in the imaging range.

  In this figure, 41 is a plastic pellet, 42 is a cylindrical lens, 43 is a wide-angle lens, and 44 is a line sensor.

  As the plastic pellet layer width D is narrower, the distance L can be shortened to the maximum angle of view Θ, so that the amount of scattered light detected can be increased by increasing the trapping angle of scattered light in the Y direction. Therefore, a wide-angle lens having a larger angle of view Θ is more effective for capturing scattered light in the X direction.

  In addition, as described above, the pixel size of the line sensor 44 is long (for example, ˜8 × 200 μm) and is set to about 2 to 10 MHz of 2400 bits, thereby increasing the amount of received light and increasing the signal intensity. As a result, it is possible to increase the accuracy and speed of positioning and increase the information amount of the plastic pellet 41.

  Further, when there is a spectrum that can be identified as backscattered light due to discoloration of the plastic pellet 41 or the like, the identification efficiency may be increased by using a spectrally distributed fluorescent lamp or the colored glass filter 29 shown in FIG. A halogen white fluorescent lamp may be provided, and an option for appropriate measurement may be provided by replacing a colored glass filter (less expensive than a fluorescent lamp) by an external operation.

  FIG. 6 is a diagram showing an assumed plastic pellet reflected signal output waveform from the line sensor camera according to the embodiment of the present invention.

  The plastic pellets are classified as non-defective products at the line sensor signal strength sorting level 51, and those that fall outside the line sensor signal strength sorting level 51 are, for example, deformed plastic pellets 52, fine plastic pellets 53, The star-shaped plastic pellet 54, the discolored body plastic pellet 55, the mixed foreign matter 56, and the like are identified as defective products, and the normal molded plastic pellets 57 other than that are identified as non-defective products. The level 51 is appropriately selected in order to distinguish the scattered light from the star-shaped pellet and the high-intensity scattered light due to the irregular reflection inside the pellet.

  In this way, foreign matter pellets, discolored pellets, and irregular shaped pellets are detected by two line sensor cameras arranged on both sides, and simultaneously with this detection, they are blown off by the air from the air ejector, and from the defective product path. Discharged.

  Depending on the color, several types of lamps can be prepared so that the foreign matter can be detected more clearly by using the principle of conditional color projection.

  In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  The plastic pellet sorter of the present invention can be used as a plastic pellet sorter capable of accurately removing foreign material-mixed pellets, discolored pellets and irregular shaped pellets.

It is a schematic diagram of the plastic pellet sorter which shows the Example of this invention. It is explanatory drawing of the light scattering of the plastic pellet which concerns on this invention. It is a principal part block diagram of the plastic pellet sorter which shows the Example of this invention. It is a ray-trajectory figure by the cylindrical lens and wide-angle lens of the plastic pellet sorter which shows the Example of this invention. It is explanatory drawing for putting the plastic pellet layer width which concerns on this invention into an imaging range. It is a figure which shows the assumption plastic pellet reflected signal output waveform from the line sensor camera which shows the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11, 31, 41 Plastic pellet 2 Hopper 3 Vibrating feeder 4 Roll feeder 5 Reference plate 6 Pair of line sensor camera 7 Pair of light sources 8 Air ejector 9 Non-defective product path 10 Defective product path 12 Irradiation light 13 Back scattered light 13A Plastic pellet Surface reflection light 13B Internal reflection light of plastic pellet 14 Forward scattered light 14A Surface reflection light of plastic pellet 14B Internal transmission light of plastic pellet 21, 31, 41 Falling plastic pellet 22 Dustproof window 23 Fluorescent lamp 24 Shielding cylinder 24A Shielding cylinder Body window 25 Cylindrical lens (takes out light from a fluorescent lamp)
26 Cylindrical lens (transmits reflected light from falling plastic pellets)
27 Light-shielding plate 27A Window through which light transmitted from cylindrical lens passes 28, 33, 43 Wide-angle lens 29 Color glass filter 30, 34, 44 Line sensor 32, 42 Cylindrical lens 51 Line sensor signal intensity selection level 52 Deformed plastic pellet 53 Small Grain plastic pellets 54 Star plastic pellets 55 Color change plastic pellets 56 Contaminated foreign matter 57 Normal molded plastic pellets

Claims (4)

  By arranging a line sensor camera equipped with a light source and a line sensor device so as to be paired on both sides of the falling plastic pellet, by measuring the back scattered light of the irradiation light from the light source, A plastic pellet sorter that detects discoloration and irregularity and sorts the good and bad plastic pellets, wherein a pair of fluorescent lamps are arranged in the vertical direction of the falling plastic pellets as the light source, Each of the pair of fluorescent lamps includes a shielding cylindrical body, a cylindrical lens is disposed in a window of the shielding cylindrical body, and the falling plastic pellet is irradiated with light from the cylindrical lens.   2. The plastic pellet sorting machine according to claim 1, wherein the reflected light from the falling plastic pellet passes through a dust-proof window and is arranged rearward through a cylindrical lens arranged between the pair of fluorescent lamps. A plastic pellet sorter that is detected by a sensor device.   3. The plastic pellet sorter according to claim 2, wherein the line sensor device includes a wide-angle lens, a colored glass filter, and a line sensor from a cylindrical lens side disposed between the pair of fluorescent lamps. Plastic pellet sorter.   2. The plastic pellet sorting machine according to claim 1, wherein when a defective product of the plastic pellet is detected, an air ejector is driven, and the defective product of the plastic pellet is blown off with air and led to a defective product path. Plastic pellet sorter.

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