Molding powder screening device

Abstract

The molding powder screening device comprises a screening box, a rotating shaft and two supporting seats, the screening box comprises an inner cavity, the inner wall of the inner cavity is defined by a cylindrical side wall and two circular bottom walls arranged at the two ends of the side wall, the two bottom walls are parallel to each other, the rotating shaft is arranged on the screening box in a penetrating mode, and the axis of the rotating shaft coincides with the center line of the side wall; the two ends of the rotating shaft are rotationally connected with the two supporting seats correspondingly, the heights of the two ends of the rotating shaft are consistent, motors for controlling the rotating shaft to rotate are arranged on the supporting seats, a first vibrator is arranged on the rotating shaft, a second vibrator is arranged on the screening box, a guide plate and a first latticed filtering plate are fixed to the rotating shaft, and a feeding port, a waste port and a discharging port are formed in the side wall of the rotating shaft. A first sealing door is arranged on the feeding opening, a second sealing door is arranged on the waste opening, the discharging opening is located in the lowest position of the side wall, and the height of the waste opening is between the feeding opening and the discharging opening. According to the plastic powder screening device, qualified plastic powder can be rapidly screened out, unqualified plastic powder can rapidly leave the inner cavity, residues cannot occur, and follow-up screening cannot be affected.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic powder processing, and in particular relates to a plastic powder screening device. Background Art

[0002] Plastic powder is a material for plastic spraying. It is a thermosetting powder coating for electrostatic spraying. It is mainly sprayed on the surface of metal products and some wooden products to increase the aesthetics and sealing performance of the material. It is a new type of decorative material that has developed rapidly in recent years. It has the characteristics of energy saving, low pollution, high efficiency and high performance. The production of plastic powder usually includes the following steps: raw material preparation, extrusion, cooling, crushing, screening and packaging.

[0003] The crushing process mainly involves processing plastic flakes or plastic pellets through cutters, crushers and grinders to obtain the required particles. Due to the limitation of equipment accuracy, the particle size of the crushed plastic powder has a large range. The particle size of the plastic powder has an important influence on the performance of the coating. In order to keep the coating in good performance, the crushed particles are usually screened.

[0004] The utility model patent with application number 202420036220.9 discloses a plastic powder screening device, which filters the product twice through a medium-pore filter and a fine-pore filter, and discharges it through the corresponding outlet. The patent is also provided with a cleaning plate and a cleaning brush to discharge the product remaining in the box. However, the above patent has the following problems: 1. The medium-pore filter and the fine-pore filter are both set horizontally, and the moving trajectory of the cleaning plate and the cleaning brush is also set horizontally. The residual products can only be concentrated, and the products remaining in the box cannot be effectively discharged, and the staff is still required to assist in the discharge; 2. As the cleaning plate and the cleaning brush are in operation, some of the residual products may be pressed into the mesh, resulting in clogging of the mesh or falling from the mesh. The former affects the subsequent screening function, and the latter affects the quality of the products after screening. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a plastic powder screening device which has good screening effect and is not prone to residue after screening.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a plastic powder screening device, comprising a screening box, a rotating shaft and two support seats arranged on both sides of the screening box, the screening box comprising an inner cavity, the inner wall of the inner cavity is surrounded by a cylindrical side wall and two circular bottom walls arranged at both ends of the side wall, the two bottom walls are parallel to each other, the rotating shaft is passed through the screening box and the axis of the rotating shaft coincides with the center line of the side wall, the two ends of the rotating shaft are respectively rotatably connected to the two support seats and the heights of the two ends of the rotating shaft are consistent, the support seat is provided with a motor for controlling the rotation of the rotating shaft, and the rotating shaft is provided with a vibrator, The screening box is provided with two vibrators, and a guide plate and a grid-shaped filter plate are fixed on the rotating shaft. The surface of the guide plate facing away from the rotating shaft abuts against the side wall, and the two surfaces of the guide plate adjacent to the rotating shaft abut against the two bottom walls respectively. The surface of the filter plate facing away from the rotating shaft abuts against the side wall, and the two surfaces of the filter plate one adjacent to the rotating shaft abut against the two bottom walls respectively. A feed port, a waste port and a discharge port are provided on the side wall, a sealing door one is provided on the feed port, a sealing door two is provided on the waste port, the discharge port is located at the lowest point of the side wall, and the height of the waste port is between the feed port and the discharge port.

[0007] When adopting the above scheme, the heights and height comparisons involved are all based on the ground when the present invention is actually used.

[0008] When the present invention is actually used, the crushed plastic powder enters the inner cavity from the feed port. At this time, the present invention is in a filtering state, that is, the filter plate 1 is located between the feed port and the discharge port, the guide plate is located between the feed port and the waste port and the guide plate is higher than the filter plate 1, and the sealing door 2 is in a closed state. The plastic powder entering the inner cavity falls onto the filter plate 1. At this time, the vibrator 1 and the vibrator 2 are in a vibrating state. After the amount of plastic powder entering the inner cavity reaches a predetermined value, the sealing door 1 is closed, and the plastic powder that meets the particle size requirements falls from the filter plate 1 and falls out from the discharge port. After vibrating until no plastic powder falls from the discharge port, the vibration stops, the motor drives the rotating shaft to rotate, the height of the side of the filter plate 1 away from the rotating shaft increases, and the height of the side of the guide plate away from the rotating shaft decreases until the guide plate is located between the discharge port and the waste port. At this time, the present invention is in a cleaning state, that is, the filter plate 1 is higher than the guide plate, and at the same time, the height of the side of the guide plate close to the rotating shaft is greater than the height of the side of the guide plate away from the rotating shaft. After the present invention is in the cleaning state, the sealing door 2 is opened, the vibrator 1 and the vibrator 2 vibrate again, and the plastic powder that does not meet the particle size requirements leaves the screening box from the waste port along the guide plate, and the plastic powder collected from the waste port can be crushed again.

[0009] Compared with the prior art, the present invention can quickly screen out qualified plastic powder and quickly allow unqualified plastic powder to leave the inner cavity without any residue and without affecting subsequent screening.

[0010] As a further configuration of the present invention, a grid-shaped filter plate 2 is fixed on the rotating shaft, the surface of the filter plate 2 facing away from the rotating shaft abuts against the side wall, the two surfaces of the filter plate 2 adjacent to the rotating shaft abut against the two bottom walls respectively, the grid size of the filter plate 2 is smaller than the grid size of the filter plate 1, a coarse material outlet is provided on the side wall, a sealing door 3 is provided at the coarse material outlet, the coarse material outlet is arranged between the feed port and the discharge port, and the feed port is arranged between the waste port and the coarse material outlet.

[0011] By adopting the above scheme, sealing door one, sealing door two and sealing door three can be connected to the screening box through threaded cooperation and opened and closed by manual control, or the three can be set as electric doors and opened and closed automatically by program.

[0012] The filter plate 2 can perform secondary filtration on the plastic powder filtered by the filter plate 1. After a predetermined amount of plastic powder enters the inner cavity, the sealing door 1, the sealing door 2 and the sealing door 3 are in a closed state until no plastic powder falls from the discharge port, and the sealing door 3 is opened. Under the action of the vibrator 1 and the vibrator 2, the plastic powder remaining on the filter plate 2 leaves the inner cavity from the coarse material outlet. Plastic powders of different particle sizes can meet different needs. When the present invention is in a filtering state, the filter plate 2 is located between the coarse material outlet and the discharge port, the filter plate 1 is located between the feed port and the coarse material outlet, and the height of the filter plate 2 close to the rotating shaft is higher than the height of the filter plate 2 away from the rotating shaft.

[0013] As a further configuration of the present invention, cleaning brushes are provided on the surfaces of the guide plate, filter plate 1 and filter plate 2 facing the side wall and the bottom wall.

[0014] By adopting the above scheme, the side walls and the bottom wall can be cleaned during the rotation of the shaft to prevent plastic powder from adhering to the side walls and the bottom wall, thereby ensuring the screening quality.

[0015] As a further configuration of the present invention, there is an angle of 120° to 150° between the guide plate and the first filter plate, and there is an angle of 50° to 70° between the first filter plate and the second filter plate.

[0016] The above scheme is adopted to ensure the filtering effect.

[0017] As a further configuration of the present invention, a sealing gasket made of elastic material is provided between the rotating shaft and the screening box, and a bearing is provided between the sealing gasket and the rotating shaft.

[0018] The above scheme can prevent the plastic powder in the inner cavity from flying out from the gap between the rotating shaft and the screening box, external pollutants from entering the inner cavity from the gap, and plastic powder from being stuck in the gap, thereby ensuring the quality of the screened plastic powder.

[0019] The bearing is a bearing with a sealed structure. The sealing gasket ensures that the shaft remains sealed when there is a small amount of relative displacement between the rotating shaft and the screening box during vibration.

[0020] As a further configuration of the present invention, the side wall is drum-shaped with the middle portion bulging outward, the coarse material outlet, the discharge port and the waste material outlet are all arranged in the middle portion of the side wall, and the feed port is an oblong hole or a rectangular hole extending along the axis of the rotating shaft.

[0021] In the above scheme, the middle part refers to the position where the distance from the side wall to the two bottom walls is consistent. The shape of the side wall facilitates the plastic powder after the first screening to be concentrated to the coarse material outlet, the plastic powder after the second screening to be concentrated to the discharge port, and the plastic powder with unqualified particle size to be concentrated to the waste port. The screening efficiency is improved, and the plastic powder is prevented from remaining in the inner cavity. The shape of the feed port allows the plastic powder entering the inner cavity to be more evenly sprinkled on the filter plate. The oblong hole is composed of two semicircles and a square arranged between the two semicircles.

[0022] As a further configuration of the present invention, an inspection opening is provided on the side wall, an inspection door is provided on the inspection opening, a sealing ring is provided on the inner wall of the inspection opening, the inspection door is hinged to the screening box on the side located at a high position, the inspection door is provided on the side located at a low position with a raised end which raises away from the rotating shaft, a fixed end is provided on the screening box at a position opposite to the raised end, and the raised end and the fixed end are fixed by bolts.

[0023] With the above solution, the inspection opening is convenient for the staff to carry out maintenance, and preferably a transparent inspection window is provided on the inspection door.

[0024] As a further configuration of the present invention, a spring is provided at the bottom of the screening box, and there are at least two springs which are arranged in sequence along the axial direction of the rotating shaft.

[0025] By adopting the above solution, the spring can prevent the screening box from vibrating too much.

[0026] As a further configuration of the present invention, a funnel-shaped receiving trough is provided at the discharge port, and a crusher is provided in the receiving trough.

[0027] With the above solution, the crushed plastic powder may be loosely fixed together due to water vapor, static electricity and the like. The crusher can pre-treat the crushed plastic powder to facilitate subsequent screening.

[0028] As a further configuration of the present invention, the crusher includes a rotating shaft passing through the receiving groove, a plurality of blade groups arranged on the rotating shaft and a driving member for controlling the rotation of the rotating shaft, all of the blade groups are arranged in sequence along the axis of the rotating shaft, a group of the blade groups includes at least two blades extending radially along the rotating shaft, the blades in the same blade group are rotationally symmetrical along the axis of the rotating shaft, and the blades in adjacent blade groups are staggered.

[0029] The above scheme has a simple structure and a good crushing effect.

[0030] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Attached Figure 1 It is a schematic diagram of a screening box according to a specific embodiment of the present invention;

[0032] Attached Figure 2 It is a front view schematic diagram of the actual use of a specific embodiment of the present invention;

[0033] Attached Figure 3 For attachment Figure 2 AA section view;

[0034] Attached Figure 4 It is a cross-sectional view of a cleaning state of a specific embodiment of the present invention;

[0035] Attached Figure 5 For attachment Figure 4 A magnified view of part B;

[0036] Attached Figure 6 It is a schematic diagram of a guide plate, a filter plate 1, and a filter plate 2 according to a specific embodiment of the present invention.

[0037] Screening box 1, inner cavity 11, side wall 111, bottom wall 112, vibrator 2 12, feed port 13, waste port 14, discharge port 15, coarse material outlet 16, sealing door 1 17, sealing door 2 18, sealing door 3 19, inspection port 1a, inspection door 1b, raised end 1b1, inspection window 1b2, fixed end 1c, rotating shaft 2, vibrator 1 21, support seat 3, motor 31, guide plate 4, filter plate 1 5, filter plate 2 6, cleaning brush 7, sealing pad 8, bearing 9, spring 10, receiving slot a1, rotating shaft a2, blade a3, driving member a4, DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be noted that, unless otherwise specified, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. used in the description to indicate the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] The specific implementation example of the present invention is Figure 1-6 shown.

[0041] A plastic powder screening device comprises a screening box 1, a rotating shaft 2 and two supporting seats 3 arranged on both sides of the screening box 1. The screening box 1 comprises an inner cavity 11, the inner wall of the inner cavity 11 is surrounded by a cylindrical side wall 111 and two circular bottom walls 112 arranged at both ends of the side wall 111, and the two bottom walls 112 are parallel to each other. The rotating shaft 2 is passed through the screening box 1 and the axis of the rotating shaft 2 coincides with the center line of the side wall 111. The two ends of the rotating shaft 2 are respectively rotatably connected to the two supporting seats 3 and the heights of the two ends of the rotating shaft 2 are consistent. The supporting seat 3 is provided with a motor 31 for controlling the rotation of the rotating shaft 2, the rotating shaft 2 is provided with a vibrator 1 21, and the screening box 1 is provided with a vibrator 2 12.

[0042] A guide plate 4, a mesh filter plate 1 5 and a mesh filter plate 2 6 are fixed on the rotating shaft 2. The mesh size of the filter plate 2 6 is smaller than the mesh size of the filter plate 1 5. The surface of the guide plate 4 facing away from the rotating shaft 2 abuts against the side wall 111. The two surfaces of the guide plate 4 adjacent to the rotating shaft 2 abut against the two bottom walls 112 respectively. The surface of the filter plate 1 5 facing away from the rotating shaft 2 abuts against the side wall 111. The two surfaces of the filter plate 1 5 adjacent to the rotating shaft 2 abut against the two bottom walls 112 respectively. The surface of the filter plate 2 6 facing away from the rotating shaft 2 abuts against the side wall 111. The surface of the filter plate 2 6 abuts against the rotating shaft 2. The two adjacent surfaces are respectively in contact with the two bottom walls 112, and the side wall 111 is provided with a feed port 13, a waste port 14, a discharge port 15 and a coarse material outlet 16. The feed port 13 is provided with a sealing door 17, the waste port 14 is provided with a sealing door 2 18, and the coarse material outlet 16 is provided with a sealing door 3 19. The discharge port 15 is located at the lowest point of the side wall 111, the height of the waste port 14 is between the feed port 13 and the discharge port 15, the coarse material outlet 16 is arranged between the feed port 13 and the discharge port 15, and the feed port 13 is arranged between the waste port 14 and the coarse material outlet 16.

[0043] The height and height comparison involved in this embodiment are based on the ground when this embodiment is actually used. In this embodiment, the sealing door 17, the sealing door 2 18 and the sealing door 3 19 are all electric doors, which are opened and closed automatically by a program.

[0044] When the present embodiment is actually used, the crushed plastic powder enters the inner cavity 11 from the feed port 13. At this time, the present embodiment is in a filtering state (see Appendix). Figure 3 As shown), filter plate 15 is located between the feed port 13 and the coarse material outlet 16, filter plate 26 is located between the coarse material outlet 16 and the discharge port 15, guide plate 4 is located between the feed port 13 and the waste material outlet 14 and guide plate 4 is higher than filter plate 15, the height of filter plate 26 close to the rotating shaft 2 is higher than the height of filter plate 26 away from the rotating shaft 2, sealing door 2 18 and sealing door 3 19 are in a closed state, and the plastic powder entering the inner cavity 11 falls onto filter plate 15, at which time vibrator 1 21 and vibrator 2 12 are in a vibrating state. When the amount of plastic powder entering the inner cavity 11 reaches a predetermined value, sealing door 17 is closed, and plastic powder that meets the particle size requirements falls from filter plate 15 to filter plate 26, and filter plate 26 performs secondary filtration on the plastic powder filtered by filter plate 15, and the plastic powder after secondary filtration falls from the discharge port 15. After vibrating until no plastic powder falls from the discharge port 15, the sealing door 3 19 is opened, and under the action of the vibrator 1 21 and the vibrator 2 12, the plastic powder remaining on the filter plate 2 6 leaves the inner cavity 11 from the coarse material outlet 16. Until no plastic powder falls from the coarse material outlet 16, the vibration stops and the sealing door 3 19 is closed, the motor 31 drives the rotating shaft 2 to rotate, the height of the side of the filter plate 1 5 away from the rotating shaft 2 is increased, and the height of the side of the guide plate 4 away from the rotating shaft 2 is decreased until the guide plate 4 is located between the discharge port 15 and the waste port 14. At this time, the present embodiment is in a cleaning state (see Appendix). Figure 4 As shown in the figure, the filter plate 1 5 is higher than the guide plate 4, and the height of the guide plate 4 close to the rotating shaft 2 is higher than the height of the guide plate 4 away from the rotating shaft 2. After the embodiment is in the cleaning state, the sealing door 2 18 is opened, the vibrator 1 21 and the vibrator 2 12 vibrate again, and the plastic powder that does not meet the particle size requirements leaves the screening box 1 from the waste port 14 along the guide plate 4, and the plastic powder collected from the waste port 14 can be crushed again.

[0045] Compared with the prior art, this embodiment can quickly screen out qualified plastic powder, and can quickly let unqualified plastic powder leave the inner cavity 11 without residue, and will not affect subsequent screening. Two or more embodiments can be set according to the crushing amount of the crushing process, and continuous screening can be achieved by staggering the screening time of each embodiment.

[0046] Cleaning brushes 7 are provided on the surfaces of the guide plate 4, the filter plate 1 5 and the filter plate 2 6 facing the side wall 111 and the bottom wall 112. The side wall 111 and the bottom wall 112 can be cleaned during the rotation of the rotating shaft 2 to prevent the plastic powder from sticking to the side wall 111 and the bottom wall 112, thereby ensuring the screening quality.

[0047] In this embodiment, the included angle e between the guide plate 4 and the filter plate 1 5 is 130°, and the included angle p between the filter plate 1 5 and the filter plate 2 6 is 60°, thereby ensuring the filtering effect.

[0048] A sealing gasket 8 made of elastic material is provided between the rotating shaft 2 and the screening box 1, and a bearing 9 with a sealing structure is provided between the sealing gasket 8 and the rotating shaft 2. The sealing gasket 8 allows the rotating shaft 2 to maintain a sealed state when a small amount of relative displacement occurs between the rotating shaft 2 and the screening box 1 during the vibration process. This prevents the plastic powder in the inner cavity 11 from flying out from the gap between the rotating shaft 2 and the screening box 1, external pollutants from entering the inner cavity 11 from the gap, and plastic powder from being stuck in the gap, thereby ensuring the quality of the screened plastic powder.

[0049] The side wall 111 is a drum-shaped one with the middle part bulging outwards. The coarse material outlet 16, the discharge port 15 and the waste material outlet 14 are all arranged in the middle part of the side wall 111. The middle part refers to the position where the distance between the side wall 111 and the two bottom walls 112 is the same. The feed port 13 is an oblong hole extending along the axis direction of the rotating shaft 2. The oblong hole is composed of two semicircles and a square arranged between the two semicircles. The shape of the side wall 111 facilitates the plastic powder after the first screening to be concentrated to the coarse material outlet 16, the plastic powder after the second screening to be concentrated to the discharge port 15, and the plastic powder with unqualified particle size to be concentrated to the waste material outlet 14. Improve the screening efficiency and prevent the plastic powder from remaining in the inner cavity 11. The shape of the feed port 13 allows the plastic powder entering the inner cavity 11 to be more evenly sprinkled on the filter plate 15.

[0050] An inspection port 1a is provided on the side wall 111, and an inspection door 1b is provided on the inspection port 1a. A sealing ring is provided on the inner wall of the inspection port 1a. The inspection door 1b is hinged to the screening box 1 on one side located at a high position, and a protruding end 1b1 protruding in a direction away from the rotating shaft 2 is provided on the one side located at a low position. A fixed end 1c is provided on the screening box 1 at a position opposite to the protruding end 1b1, and the protruding end 1b1 and the fixed end 1c are fixed by bolts. The inspection port 1a is convenient for the staff to carry out maintenance. In this embodiment, a transparent inspection window 1b2 is provided on the inspection door 1b.

[0051] A spring 10 is provided at the bottom of the screening box 1, and there are at least two springs 10 arranged in sequence along the axial direction of the rotating shaft 2. The spring 10 can prevent the screening box 1 from vibrating too much.

[0052] A funnel-shaped receiving groove a1 is provided at the discharge port 15, and a rotating shaft a2 and a driving member a4 for controlling the rotation of the rotating shaft a2 are provided on the receiving groove a1. A plurality of blade groups are provided on the rotating shaft a2, and all blade groups are arranged in sequence along the axis of the rotating shaft a2. One blade group includes at least two blades a3 extending radially along the rotating shaft a2. The blades a3 in the same blade group are rotationally symmetrical along the axis of the rotating shaft a2, and the blades a3 in adjacent blade groups are staggered. The crushed plastic powder may be loosely fixed together due to water vapor, static electricity, etc. The crusher can pre-treat the crushed plastic powder to facilitate subsequent screening.

[0053] The present invention is not limited to the above-mentioned specific implementation modes. A person skilled in the art may adopt other various specific implementation modes to implement the present invention based on the contents disclosed in the present invention, or any simple changes or modifications made to the design structure and concept of the present invention shall fall within the protection scope of the present invention.

Claims

1. A plastic powder screening device, comprising a screening box, characterized in that: The screen box further comprises a rotating shaft and two supporting seats arranged on both sides of the screen box, the screen box comprises an inner cavity, the inner wall of the inner cavity is surrounded by a cylindrical side wall and two circular bottom walls arranged at both ends of the side wall, the two bottom walls are parallel to each other, the rotating shaft is passed through the screen box and the axis of the rotating shaft coincides with the center line of the side wall, the two ends of the rotating shaft are respectively rotatably connected to the two supporting seats and the heights of the two ends of the rotating shaft are consistent, the supporting seat is provided with a motor for controlling the rotation of the rotating shaft, the rotating shaft is provided with a vibrator 1, the screening box is provided with a vibrator 2, and the rotating shaft is provided with a plurality of rotating shafts. A guide plate and a grid-shaped filter plate 1 are fixed, the surface of the guide plate facing away from the rotating shaft abuts against the side wall, the two surfaces of the guide plate adjacent to the rotating shaft abut against the two bottom walls respectively, the surface of the filter plate 1 facing away from the rotating shaft abuts against the side wall, the two surfaces of the filter plate 1 adjacent to the rotating shaft abut against the two bottom walls respectively, a feed port, a waste port and a discharge port are provided on the side wall, a sealing door 1 is provided on the feed port, a sealing door 2 is provided on the waste port, the discharge port is located at the lowest point of the side wall, and the height of the waste port is between the feed port and the discharge port.

2. A plastic powder screening device according to claim 1, characterized in that: A grid-shaped filter plate 2 is fixed on the rotating shaft, the surface of the filter plate 2 facing away from the rotating shaft abuts against the side wall, and the two surfaces of the filter plate 2 adjacent to the rotating shaft abut against the two bottom walls respectively, the grid size of the filter plate 2 is smaller than the grid size of the filter plate 1, a coarse material outlet is provided on the side wall, a sealing door 3 is provided at the coarse material outlet, the coarse material outlet is arranged between the feed port and the discharge port, and the feed port is arranged between the waste port and the coarse material outlet.

3. A plastic powder screening device according to claim 2, characterized in that: Cleaning brushes are arranged on the surfaces of the guide plate, the first filter plate and the second filter plate facing the side wall and the bottom wall.

4. A plastic powder screening device according to claim 2 or 3, characterized in that: There is an angle of 120° to 150° between the guide plate and the first filter plate, and there is an angle of 50° to 70° between the first filter plate and the second filter plate.

5. A plastic powder screening device according to claim 4, characterized in that: A sealing gasket made of elastic material is arranged between the rotating shaft and the screening box, and a bearing is arranged between the sealing gasket and the rotating shaft.

6. A plastic powder screening device according to claim 5, characterized in that: The side wall is in the shape of a drum with the middle part bulging outwards. The coarse material outlet, the discharge port and the waste material outlet are all arranged in the middle part of the side wall. The feed port is an oblong hole or a rectangular hole extending along the axis of the rotating shaft.

7. A plastic powder screening device according to claim 6, characterized in that: An inspection opening is provided on the side wall, an inspection door is provided on the inspection opening, a sealing ring is provided on the inner wall of the inspection opening, the inspection door is hinged to the screening box on the side located at a high position, a raised end is provided on the side located at a low position and raised in a direction away from the rotating shaft, a fixed end is provided on the screening box at a position opposite to the raised end, and the raised end and the fixed end are fixed by bolts.

8. A plastic powder screening device according to claim 7, characterized in that: The bottom of the screening box is provided with springs, and there are at least two springs which are arranged in sequence along the axial direction of the rotating shaft.

9. A plastic powder screening device according to claim 8, characterized in that: A funnel-shaped receiving trough is provided at the discharge port, and a crusher is provided in the receiving trough.

10. A plastic powder screening device according to claim 9, characterized in that: The crusher includes a rotating shaft passing through the receiving groove, a plurality of blade groups arranged on the rotating shaft and a driving member for controlling the rotation of the rotating shaft, all of the blade groups are arranged in sequence along the axis of the rotating shaft, a group of the blade groups includes at least two blades extending radially along the rotating shaft, the blades in the same blade group are rotationally symmetrical along the axis of the rotating shaft, and the blades in adjacent blade groups are staggered.

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