Device for removing foreign matters from waste plastics

Abstract

The present disclosure relates to an apparatus for removing foreign matter from waste plastic, and more particularly, to an apparatus for removing foreign matter from waste plastic, which removes foreign matter adhering to the surface of waste plastic by enhancing the frictional performance of the surface of a waste plastic sheet, and the cooling performance is improved by supplying moisture to the friction heat generated at this time in the form of mist.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority and benefits of Korean Patent Application No. 10 - 2023 - 0138482, filed on October 17, 2023, and Korean Patent Application No. 10 - 2024 - 0087906, filed on July 4, 2024, the entire contents of which are incorporated herein by reference. Technical field

[0003] The present invention relates to a device for removing foreign substances from waste plastics, and more particularly, to a device capable of removing foreign substances attached to the surface of waste plastics by rubbing the surface of the waste plastics and controlling the frictional heat generated during the removal process. Background art

[0004] As environmental regulations triggered by global warming are being implemented worldwide, efforts are being made to recycle and utilize plastics. The biggest problem with recycling plastics for resource circulation is foreign substances. When adhesives or coatings are attached to plastics during the manufacturing process of products, or when plastics are contaminated during user use, even if the plastics are recycled, it is difficult to process the plastics for reuse, and since the process of removing foreign substances is not environmentally friendly, recycling plastics often loses its meaning.

[0005] Specifically, even when plastics such as ABS resin or polypropylene (PP) used in electronic products are recycled, foreign substances such as adhesives, coatings, or paints used during product manufacturing remain on their surfaces, resulting in poor appearance quality, which greatly limits the use of plastics during recycling. In the past, methods that mainly use organic solvents or acidic substances to dissolve foreign substances to remove them from the surface of waste plastics have been studied and used, but chemical treatment methods are not preferred in terms of cost or environmental impact because they produce harmful secondary emissions. Therefore, eco - friendly physical recycling technologies are needed to replace chemical recycling technologies to remove foreign substances attached to waste plastics.

[0006] As a conventional physical method, a method of crushing waste plastics and then rubbing the crushed waste plastics to remove foreign substances on the surface has been applied. However, in order to sufficiently remove foreign substances on the surface of waste plastics using physical methods, several rubbing treatments must be repeated. However, frictional heat is generated during the rubbing process, heating the raw materials. Therefore, there is a problem of cooling the raw materials in order to repeat the rubbing process. Therefore, it is necessary to study a physical recycling method that can effectively remove foreign substances on the surface of waste plastic sheets while controlling frictional heat. Summary of the invention

[0007] [Technical problems]

[0008] The present disclosure provides an apparatus for removing foreign substances from waste plastics, which can improve the performance of removing foreign substances by controlling the frictional heat generated when removing foreign substances attached to the surface of waste plastics by supplying moisture to rub the surface of the waste plastics.

[0009] However, the problems to be solved by the present disclosure are not limited to the above aspects. That is to say, those skilled in the art can clearly understand other aspects not described from the following description.

[0010] [Technical Solution]

[0011] According to an embodiment of the present invention, there is provided an apparatus for removing foreign substances from waste plastics, which includes: a waste raw material injection unit provided at the upper part of one side to inject waste plastic sheets; a foreign substance removal unit that removes foreign substances attached to the waste plastic sheets by friction; and a raw material outlet provided at the other side to discharge the waste plastic sheets from which foreign substances have been removed.

[0012] In addition, the apparatus for removing foreign substances from waste plastics according to an embodiment of the present invention includes a friction net provided inside the foreign substance removal unit to accommodate the waste plastic sheets supplied from the waste raw material injection unit.

[0013] The apparatus for removing foreign substances from waste plastics according to an embodiment of the present invention includes a rotating shaft, on the outer peripheral surface of which friction blades are provided. The rotating shaft is rotatably provided inside the friction net and peels off the foreign substances attached to the waste plastic sheets by rubbing the waste plastic sheets in a rotating manner.

[0014] In addition, the apparatus for removing foreign substances from waste plastics according to an embodiment of the present invention includes a moisture injection nozzle provided at one end of the rotating shaft to supply moisture to the foreign substance removal unit.

[0015] In addition, the rotating shaft includes a moisture injection path and a moisture supply port. The moisture injection path is provided in the rotating shaft to supply and transport moisture from the moisture injection nozzle, and the moisture supply port is provided on one surface of the friction blade to discharge the moisture from the moisture injection path to the outside of the rotating shaft and supply the moisture to the foreign substance removal unit.

[0016] [Advantageous Effects]

[0017] The apparatus for removing foreign substances from waste plastics according to an embodiment of the present invention can provide improved foreign substance removal ability by enhancing the frictional performance of the surface of the waste plastic sheets and expand the friction limit by enhancing the cooling function of the surface of the waste plastic sheets.

[0018] Specifically, the device for removing foreign substances from waste plastics according to an embodiment of the present invention can remove foreign substances on the surface of waste plastic flakes by uniformly supplying atomized moisture during the friction treatment process, can cool the frictional heat, and can expand the foreign substances on the surface of the waste plastic flakes, thereby easily removing the foreign substances.

[0019] In addition, by having a closed structure to minimize the inflow of outside air into the device, reducing the air pressure in the friction treatment area to remove foreign substances, and using the sensible heat of the supplied moisture and the latent heat generated during evaporation for cooling, the cooling effect of the waste plastic flakes can be maximized.

[0020] The effects that can be achieved by the present disclosure are not limited to the above effects. That is, those skilled in the art to which the present disclosure pertains can clearly understand other purposes not described from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional view showing the structure of a device for removing foreign substances from waste plastics according to an embodiment of the present disclosure.

[0022] Figure 2 is along Figure 1 sectional view taken along line A-A'.

[0023] Figure 3 is a cross-sectional view showing the structure of a device for removing foreign substances from waste plastics according to an embodiment of the present disclosure.

[0024] Figure 4 is along Figure 3 sectional view taken along line B-B'. DETAILED DESCRIPTION

[0025] The terms and words used in this specification and the claims should not be construed as having a general meaning or a dictionary meaning, but should be construed as having a meaning and concept that satisfy the technical spirit of the present disclosure based on the principle that the inventor can appropriately define the terms in order to describe their own invention in the best way.

[0026] In combination with the description of the drawings, like reference numerals may be used for like or related components.

[0027] The singular form of a noun corresponding to an item may include one or more of the items, unless the relevant context clearly indicates otherwise.

[0028] In the present disclosure, each phrase such as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B or C" may include any one or all possible combinations of the items listed together in the respective one of these phrases.

[0029] The term "and / or" includes combinations of multiple related described components or any one of the multiple related described components.

[0030] Terms such as "first", "second", "1st", "2nd", etc. may be used only to distinguish one component from other components and do not limit the corresponding components in other respects (e.g., importance or order).

[0031] In addition, terms such as "front", "rear", "top", "bottom", "side", "left", "right", "inner", "outer", "upper", "lower", "inner side", "outer side", etc. used herein are defined based on the drawings, and the shape and position of each component are not limited by this term.

[0032] It should be understood that the term "comprising" or "having" used in the present disclosure specifies the presence of the features, numbers, steps, operations, components, parts, or combinations thereof mentioned in this specification, but does not exclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0033] When a component is "connected", "coupled", "supported", or "contacted" with another component, this includes not only the case where the component is directly connected, coupled, supported, or contacted, but also the case where the component is indirectly connected, coupled, supported, or contacted through a third component.

[0034] When a part is "on" another part, this includes not only the case where the part is in contact with the other part, but also the case where there is another part between the two parts.

[0035] Terms such as "about", "substantially", etc. used herein are used in a numerical or near-numerical sense when presenting manufacturing and material tolerances inherent in the recited meanings, and are used to prevent unscrupulous infringers from unfairly using the disclosure that mentions exact values or absolute values to aid in understanding the present disclosure.

[0036] It should be noted that the "pressure" mentioned herein refers to the gauge pressure measured based on atmospheric pressure.

[0037] As used herein, the "raw material" refers to plastic. In addition, the "waste plastic" as used herein may include natural polymers, synthetic polymers, or mixtures thereof, and the synthetic polymers may include thermoplastic resins such as polyethylene (PE), polypropylene (PP), and polystyrene. Additionally, the thermoplastic resins may be mixed with other types of resins such as PVC (polyvinyl chloride), PET (polyethylene terephthalate), and thermosetting resins.

[0038] Before describing the present disclosure, it should be noted that motors required for rotational power, blower fans required for blowing air, intake fans for sucking in air, etc. are not the gist of the present disclosure, and thus will not be described in detail and are not shown in the drawings.

[0039] As a conventional physical method for removing foreign substances from waste plastic, a method of crushing waste plastic and then rubbing the crushed waste plastic to remove foreign substances on the surface has been applied. However, in order to sufficiently remove foreign substances on the surface of waste plastic using a physical method, several rubbing processes must be repeated. Additionally, in an open-structured device, while maintaining suction by a blower, external air is sucked in and dust generated during rubbing processing is discharged. However, during rubbing processing, frictional heat is generated and the raw material is heated. Therefore, there is a problem that the raw material should be cooled in order to repeat the rubbing process.

[0040] Therefore, in the present disclosure, in order to effectively remove foreign substances on the surface of waste plastic sheets while controlling frictional heat, the existing open-structured device is designed to be changed to a closed structure as much as possible to minimize the inflow of external air, thereby reducing the air pressure in the foreign substance removal unit where rubbing processing is performed. In addition, by designing the device such that moisture can be centrally supplied to the foreign substance removal unit through a rotating shaft, the moisture can be uniformly injected onto the waste plastic sheets to achieve a cooling effect for frictional heat, and the supplied moisture can serve to allow foreign substances on the surface of the waste plastic sheets to be easily removed by rubbing.

[0041] The device for removing foreign substances from waste plastic according to the present disclosure will be described below with reference to the drawings, but the drawings are exemplary and the scope of the device for removing foreign substances from waste plastic is not limited thereto.

[0042] Figure 1 and Figure 3 are cross-sectional views schematically showing the structure of a device for removing foreign substances from waste plastic according to an embodiment of the present disclosure, Figure 2 and Figure 4 are cross-sectional views taken along line A-A' of Figure 1 and line B-B' of Figure 3 respectively, and show the structure of the foreign substance removal unit of the device for removing foreign substances from waste plastic.

[0043] AsFigure 1 As shown, the device 100 for removing foreign substances from waste plastics according to the present invention includes: a waste raw material injection unit 110 provided at the upper part of one side for injecting waste plastic sheets WP; a foreign substance removal unit 120 for removing foreign substances attached to the waste plastic sheets by friction; and a raw material outlet 150 provided at the other side for discharging the waste plastic sheets P after removing foreign substances.

[0044] In addition, the device 100 for removing foreign substances from waste plastics according to the present disclosure may include a main body configured in a box-shaped housing, a friction net 121 accommodated inside the main body, a rotating shaft 130 provided to pass through the center of the main body and the friction net, and a moisture injection nozzle 140 provided at one end of the rotating shaft. In addition, an injection screw 131 may be provided in the waste raw material injection unit area on the outer peripheral surface of the rotating shaft 130, friction blades 132 may be provided in the foreign substance removal unit area, a moisture injection path 133 may be provided inside the rotating shaft 130 so that the moisture M supplied from the moisture injection nozzle 140 can move, and a moisture supply port 134 connecting the inner area and the outer area of the rotating shaft may be provided.

[0045] In addition, as Figure 3 shown, the device 100' for removing foreign substances from waste plastics according to an example may further include a porous guide 141 connected to one end of the moisture injection nozzle 140.

[0046] The waste raw material injection unit 110 may include: an injection hopper 111 provided at the upper part of one side of the main body; an injection path 112 provided inside the main body and connected to the injection hopper; and a hopper cover 113 provided on the upper part of the injection hopper.

[0047] The injection hopper 111 may be provided at the upper part of one side of the main body and may inject the waste plastic sheets WP into the device 100 for removing foreign substances from waste plastics.

[0048] In addition, the injection path 112 may be connected to the injection hopper 111 and may convey the waste plastic sheets WP supplied from the injection hopper 111 to the foreign substance removal unit 120. Here, an injection screw 131 for conveying the waste plastic sheets WP to the foreign substance removal unit 120 may be provided on the outer peripheral surface of the rotating shaft 130 located on the injection path 112. The above injection screw 131 may convey the waste plastic sheets WP injected from the injection hopper 111 to the foreign substance removal unit 120 as the rotating shaft 130 rotates.

[0049] Meanwhile, the waste plastic sheet WP can be pretreated before being injected into the device 100 for removing foreign matters from waste plastics, and can be obtained by crushing and cutting the collected waste plastics into small pieces and pulverizing the sheet-shaped waste plastics into smaller pieces. When the size of the waste plastic sheet WP injected into the device 100 for removing foreign matters from waste plastics is too large, the waste plastic sheet WP may be blocked in the injection hopper 111 or unable to enter the pitch of the injection screw 131, so it may be difficult to convey it to the foreign matter removal unit 120. On the other hand, when the size of the waste plastic sheet WP is too small, the waste plastic sheet WP escapes through the plurality of holes 122 of the friction net 121 described below, so that even the raw materials to be recycled may be lost. For example, the average particle size of the waste plastic sheet WP can be about 5 mm to 30 mm, specifically about 10 mm to 25 mm, but is not limited thereto.

[0050] In addition, a hopper cover 113 can be provided on the upper part of the input hopper 111 to block the inflow of external air. By providing the hopper cover, the inflow of external air into the device can be blocked, so that the internal configuration of the device is configured as a closed structure, which can be conducive to controlling the pressure inside the device. In this case, a separate raw material injection port (not shown) for injecting the waste plastic sheet into the injection hopper 111 can be provided on one side of the hopper cover 113.

[0051] The friction net 121 can be provided inside the foreign matter removal unit 120 to accommodate the waste plastic sheet WP supplied from the waste raw material injection unit 110. More specifically, the friction net 121 can be provided with a plurality of holes 122 on its front surface, and discharge the foreign matter F peeled off from the waste plastic sheet to the outside of the friction net through the plurality of holes.

[0052] The friction net 121 can be formed into any one of a polygonal tubular structure and a cylindrical structure. That is, Figure 1 The A-A' cross-section of the shown friction net 121 can be polygonal or circular, and for example, the polygon can be hexagon to decagon, more specifically, octagon. In particular, when the friction net has a polygonal structure, the foreign matter removal effect can be improved while maintaining the foreign matter peeling treatment amount on the surface of the waste plastic sheet rubbed by the friction blade 132 rotating in the friction net 121 at an appropriate level. More specifically, the smaller the angle of the friction net (121), the closer the distance to the friction blade 132, which can increase the pressure and friction force applied to the waste plastic sheet WP. However, when the pressure and friction force applied to the waste plastic sheet WP increase excessively, the resistance to the torque applied to the rotating shaft 130 may increase, so the number of angles of the friction net 121 can be selectively applied according to the type of waste plastic and the degree of contamination of foreign matter attachment.

[0053] The plurality of holes 122 are holes penetrating from the inner surface to the outer surface of the friction net 121, and can be densely formed on the entire surface of the friction net. The shape of the holes 122 can be circular or rectangular, but is not limited thereto. When the holes 122 are rectangular, since the waste plastic sheet WP has a movement pattern of gently moving forward by the friction blades described later, it may be effective in the surface peeling treatment of the waste plastic sheet. In addition, the sizes of the plurality of holes 122 can be adjusted such that the waste plastic sheet WP cannot pass through, and only the peeled foreign matter F can be discharged. For example, when the shape of the holes 122 is circular, the diameter of the holes can be about 4 mm or less, specifically about 1 mm to 4 mm, and more specifically about 2 mm to 40 mm, but is not limited thereto. As another example, when the shape of the holes 122 is rectangular, i.e., slit-shaped, the width of the holes can be about 3 mm or less, specifically about 1 mm to 2 mm, and the length of the holes can be about 0.5 cm or more, specifically about 1 cm to 5 cm, but is not limited thereto.

[0054] For example, when the holes 122 are rectangular, the holes 122 can have a predetermined inclination with respect to the horizontal line of the friction net 121, and can be inclined in the range of, for example, 0° to 30°, specifically in the range of 5° to 10°. When this inclination range is satisfied, foreign matter can be sufficiently removed while preventing excessive loss of raw materials.

[0055] Meanwhile, referring to Figure 1 , the rotating shaft 130 has friction blades 132 provided on the outer surface located in the foreign matter removal unit 120, and the rotating shaft 130 is rotatably provided inside the friction net 121 to frictionally rotate the waste plastic sheet WP in a rotational manner, thereby peeling off the foreign matter attached to the waste plastic sheet. More specifically, the friction blades 132 can peel off the foreign matter attached to the surface by frictionally rubbing the waste plastic sheet WP conveyed from the injection unit 112 to the foreign matter removal unit 120 by the rotational operation of the injection screw 131.

[0056] Here, the friction blade 132 can have one edge, and as Figure 2 shown, one or more friction blades having one edge can be provided on the outer peripheral surface of the rotating shaft, and more specifically, two are provided. The surface peeling of the waste plastic sheet is performed by the friction of the edge portion of the friction blade, and at the same time, the melting of the waste plastic sheet generated by the frictional heat can be minimized.

[0057] The friction blade 132 may have a predetermined twist angle based on the longitudinal direction of the rotation axis. Even when the friction blade 132 is set to have no twist angle, i.e., the twist angle is 0°, the waste plastic flakes supplied by the injection screw 131 can be conveyed toward the raw material outlet 150 by pressure. However, when the friction blade 132 has a predetermined twist angle (i.e., a twist angle exceeding 0°), the advantage is that it can additionally receive a moment advancing toward the raw material outlet 150.

[0058] For example, the friction blade 132 may have a twist angle of 0° to 50°, specifically 20° to 40°, and more specifically 25° to 35° with respect to the longitudinal direction of the rotation axis. Due to the twist angle of the friction blade 132, the waste plastic sheets WP in the foreign matter removal unit 120 can be conveyed toward the raw material outlet 150, and at the same time, can rub against the holes of the friction mesh to strip foreign matters. In addition, when the twist angle of the friction blade 132 satisfies the above range, the loss of raw materials can be minimized while improving the foreign matter removal efficiency. More specifically, when the twist angle of the friction blade 132 is too large, due to the rotational force of the rotation axis 130, the foreign matter removal rate may decrease as the motor load increases. On the other hand, when the twist angle of the friction blade 132 is too small, the motor load may decrease, but the raw material loss rate may increase due to excessive friction.

[0059] In addition, a moisture injection nozzle 140 is provided at one end of the rotation axis 130 to supply moisture M to the foreign matter removal unit 120. As Figure 1 shown, the moisture injection nozzle 140 can inject moisture M from the direction where the raw material outlet 150 is located toward the direction of the waste raw material injection unit 110.

[0060] In this case, it is preferable that the moisture M is supplied in a mist state. By supplying the moisture M in a mist state, the moisture can be evenly sprayed on the waste plastic flakes. In this way, the frictional heat generated by the friction of the waste plastic flakes can be cooled by using the latent heat generated during the evaporation of the moisture, and the foreign matters on the surface of the waste plastic flakes can be swollen, making it easier to remove the foreign matters by friction.

[0061] Referring to Figure 1 and Figure 2 , the rotation axis 130 may be provided with a moisture injection path 133 for conveying the moisture M supplied from the moisture injection nozzle 140 and a moisture supply port 134 for discharging the moisture M from the inside of the rotation axis to the outside. In addition, in addition to moisture, air can also be conveyed through the moisture injection path 133 and the moisture supply port 134.

[0062] A water injection path 133 is provided inside the rotating shaft, and water can be supplied and transported from a water injection nozzle 140 provided at one end of the rotating shaft. Here, the water injection path 133 may have a structure with both sides closed. Due to this closed structure, the internal pressure of the foreign matter removal unit 120 can be reduced to create a vacuum condition, thereby creating an environment in which water can easily evaporate, and the cooling efficiency can be improved by utilizing the latent heat generated during evaporation. The internal pressure of the foreign matter removal unit 120 can be determined according to the output of a blower (intake fan, not shown) and the airtightness. As the internal pressure of the foreign matter removal unit 120, for example, a negative pressure of 0 mmHg to 500 mmHg, particularly 200 mmHg to 300 mmHg, can be applied. When the internal pressure is formed as a negative pressure, the evaporation point of water can be reduced, thereby improving the cooling efficiency.

[0063] In addition, in order to increase the distributability of the water M, a porous guide 141 can be further provided at one end of the water injection nozzle 140. Referring to Figure 3 and Figure 4 , the porous guide 141 can be provided to penetrate the water injection path 133 provided inside the rotating shaft. Specifically, the porous guide can be provided to extend in the longitudinal direction of the rotating shaft and be spaced apart from the inner wall of the rotating shaft provided with the water injection path. When the porous guide 141 is further provided at the end of the water injection nozzle 140, water can be transported to the water injection path located at the other end of the rotating shaft, thereby enabling uniform supply and thus further improving the distributability of water. In this case, the water supplied from the porous guide 141 is in a mist state.

[0064] A water supply port 134 is provided on one surface of the friction blade 132 to discharge water from the water injection path 133 to the outside of the rotating shaft, thereby supplying the water M to the foreign matter removal unit 120. The water supply unit is in the form of a slit, and a plurality of them can be formed at a constant interval along the edge of the friction blade 132. As a result, water and air can be transported toward the waste plastic sheet WP distributed in the entire friction treatment section of the foreign matter removal unit 120, thereby uniformly spraying water inside the friction net 121 while discharging the peeled foreign matter F to the outside of the friction net 121. In addition, since the water injection area also rotates due to the rotation of the rotating shaft provided with the water supply port, water can be supplied to the waste plastic sheet more uniformly.

[0065] More specifically, referring to Figure 2 , the water supply port 134 is provided parallel to the longitudinal direction of the edge of the friction blade 132, and can be positioned in the direction opposite to the direction in which the rotating shaft 130 rotates based on the edge of the friction blade 132. More specifically, referring to Figure 2, when the friction blade 132 with an edge has a front surface a and a rear surface b based on the edge with respect to the direction of rotation (counterclockwise) of the rotating shaft 130, preferably, the water supply port 134 is located at the rear surface b of the friction blade 132. Since the water supply port 134 is located in the direction opposite to the direction of rotation of the rotating shaft, that is, at the rear surface b of the friction blade, it is possible to prevent the waste plastic sheet WP from getting stuck in the water supply port 134, and it is also possible to uniformly supply the moisture M to the waste plastic sheets in the friction net.

[0066] In addition, the water supply port 134 can be formed along the longitudinal direction of the rotating shaft from one side to the other side of the foreign matter removal unit, so as to uniformly spray the moisture onto the waste plastic sheets, and can play a role in easily removing the foreign matter on the surface of the waste plastic sheets through the friction of the supplied moisture. In addition, the supplied moisture can play a cooling role to prevent the plastic sheets from being heated to the glass transition temperature (Tg) or higher due to the frictional heat that may be generated during the friction process. In addition, since the pressure in the foreign matter removal unit is reduced due to the closed structure, the latent heat generated during evaporation and the sensible heat of the supplied moisture are used together for cooling, thereby maximizing the resin cooling effect.

[0067] Therefore, the internal temperature of the foreign matter removal unit 120 can be maintained at or below the glass transition temperature (Tg) of the raw material, for example, in the range of 20°C to 100°C, especially in the range of 50°C to 80°C. By maintaining the internal temperature of the foreign matter removal unit 120 within the above range, it is possible to prevent the waste plastic sheets from melting due to the heat generated during the friction processing.

[0068] At the same time, the waste plastic sheets P from which foreign matter has been finally removed through the friction treatment in the foreign matter removal unit 120 are discharged through the raw material outlet 150. More specifically, the waste plastic sheets WP attached with foreign matter are injected into the waste raw material injection unit 110, and are subjected to friction treatment in the foreign matter removal unit 120 to peel off the foreign matter, and the waste plastic sheets WP from which the foreign matter has been removed can be discharged through the discharge tray provided in the raw material outlet 150.

[0069] In addition, a damper 151 for opening and closing the raw material outlet 150 can be provided between the foreign matter removal unit 120 and the raw material outlet 150. In addition, the damper 151 can be provided with a damper pressure control unit 152, and the damper pressure control unit 152 determines the internal pressure of the foreign matter removal unit.

[0070] The damper 151 applies pressure to the waste plastic sheets WP located in the foreign matter removal unit 120 according to the weight set by the damper pressure control unit 152, thereby increasing the friction between the waste plastic sheets.

[0071] Meanwhile, the foreign object outlet 160 can be disposed at the lower part of the foreign object removal unit 120 to discharge the foreign object F peeled from the waste plastic sheet through the foreign object removal unit. The foreign object F peeled from the waste plastic sheet and discharged to the outside of the friction net 121 through the holes 122 of the friction net can be collected along the downward direction of the foreign object removal unit 120 and finally discharged to the outside of the device through the foreign object outlet 160.

[0072] As described above, the device for removing foreign objects from waste plastics according to the present invention is shown in the specification and the drawings. However, the above-mentioned drawings and the specification only describe and illustrate the components necessary for understanding the present invention. In addition to the processes and devices shown in the above description and the drawings, the processes and devices not separately described and shown can be appropriately applied and used to implement the device for removing foreign objects from waste plastics according to the present disclosure.

[0073] In the foregoing, the exemplary embodiments of the present disclosure have been described. However, the present disclosure is not limited thereto, and those of ordinary skill in the art will be able to understand that various changes and modifications are possible within the scope and scope of the claims set forth below.

[0074] [Description of Reference Numerals]

[0075] 100, 100': Device for removing foreign objects from waste plastics

[0076] 110: Waste raw material injection unit, 111: Injection hopper, 112: Injection path, 113: Hopper lid

[0077] 120: Foreign object removal unit, 121: Friction net, 122: Hole

[0078] 130: Rotating shaft, 131: Injection screw, 132: Friction blade

[0079] 133: Moisture injection path, 134: Moisture supply port

[0080] 140: Moisture injection nozzle, 141: Porous guide

[0081] 150: Raw material outlet, 151: Damper, 152: Damper pressure control unit

[0082] 160: Foreign object outlet

[0083] WP: Waste plastic sheet before friction treatment

[0084] P: Waste plastic sheet after friction treatment

[0085] F: Peeled foreign object

[0086] M: Moisture

Claims

1. A device for removing foreign matter from waste plastics, comprising: a waste material injection unit, the waste material injection unit being arranged at an upper portion of one side to inject waste plastic flakes; a foreign matter removal unit that removes foreign matter attached to the waste plastic flakes by friction; and a raw material outlet that is provided on the other side portion to discharge the waste plastic flakes from which the foreign matter has been removed, a friction net provided in the foreign matter removing unit to receive the waste plastic flakes supplied from the waste raw material injecting unit; a rotating shaft having friction blades provided on an outer circumferential surface thereof, the rotating shaft being rotatably provided inside the friction net and peeling off foreign matter attached to the waste plastic flakes by rubbing the waste plastic flakes in a rotational manner; and a moisture injection nozzle provided at one end of the rotating shaft to supply moisture to the foreign matter removing unit, Wherein, the rotating shaft comprises: a moisture injection path provided in the rotating shaft and supplied with moisture by the moisture injection nozzle and conveying the moisture; and A moisture supply port is provided on one surface of the friction blade to discharge moisture from a moisture injection path to the outside of the rotating shaft and to supply moisture to the foreign matter removing unit.

2. The device according to claim 1, wherein: The moisture injection nozzle injects moisture from the direction where the raw material outlet is located toward the direction where the waste raw material injection unit is located.

3. The device according to claim 1, wherein: The moisture supply port is provided in parallel with a longitudinal direction of an edge of the friction blade, and is positioned in a direction opposite to a direction in which the rotation shaft rotates based on the edge of the friction blade.

4. The device according to claim 3, wherein: The friction blade has a twist angle of 0° to 50° based on the longitudinal direction of the rotation axis.

5. The device according to claim 1, wherein: The moisture injection path has a structure with two sides closed.

6. The device according to claim 1, wherein: The waste material injection unit comprises: an injection hopper for injecting the waste plastic flakes; an injection path for conveying the waste plastic flakes supplied from the injection hopper to the foreign matter removing unit; and A hopper cover is provided on the upper portion of the injection hopper to block the inflow of external air.

7. The device according to claim 1, wherein: An injection screw is provided on an outer peripheral surface of the rotation shaft located in the injection path to convey the waste plastic flakes to the foreign matter removing unit.

8. The device according to claim 1, wherein: The raw material export also includes: a damper provided between the foreign matter removing unit and the raw material outlet to open and close the raw material outlet; and A damper pressure control unit determines an internal pressure of the foreign matter removing unit.

9. The device according to claim 1, wherein: A plurality of holes are provided on the front surface of the friction net, and Foreign matters separated from the waste plastic flakes are discharged to the outside of the friction net through the plurality of holes.

10. The device according to claim 1, further comprising: A foreign matter outlet is provided at a lower portion of the foreign matter removing unit to discharge foreign matters peeled off from the waste plastic flakes in the foreign matter removing unit.

11. The device according to claim 1, wherein: The friction net is formed into any one structure selected from a polygonal tubular structure and a cylindrical structure.

12. The device according to claim 11, wherein The polygon is a hexagon or a decagon.

13. The device according to claim 1, wherein: The moisture injection nozzle supplies moisture in a mist state.

14. The apparatus according to claim 1, further comprising: A porous guide is connected to one end of the moisture injection nozzle and extends to be separated from an inner wall of the rotating shaft where the moisture injection path is provided.

Images