Plast powder screening device

Abstract

The application discloses a plastic powder screening device, which 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 surrounded by a cylindrical side wall and two circular bottom walls arranged at two ends of the side wall, the two bottom walls are parallel to each other, the rotating shaft is arranged on 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 rotationally connected with the two supporting seats respectively and the heights of the two ends of the rotating shaft are consistent, a motor for controlling the rotation of the rotating shaft is arranged on the supporting seat, a vibrator one is arranged on the rotating shaft, a vibrator two is arranged on the screening box, a guide plate and a grid-shaped filter plate one are fixed on the rotating shaft, a feeding port, a waste port and a discharging port are arranged on the side wall, a sealing door one is arranged on the feeding port, a sealing door two is arranged on the waste port, the discharging port is located at the lowest part of the side wall, the height of the waste port is between the feeding port and the discharging port, the qualified plastic powder can be quickly screened out, the unqualified plastic powder can quickly leave the inner cavity, no residue is left and the subsequent screening is not affected.

Description

Technical Field

[0001] This invention belongs to the field of plastic powder processing technology, and specifically relates to a plastic powder screening device. Background Technology

[0002] Powder coating is a material used in powder coating processes. It is a thermosetting powder coating used for electrostatic spraying, mainly sprayed onto the surface of metal products and some wood products to enhance their aesthetics and sealing performance. It is a new type of decorative material that has developed rapidly in recent years, featuring energy saving, low pollution, high efficiency, and high performance. The production of powder coating typically includes the following steps: raw material preparation, extrusion, cooling, crushing, sieving, and packaging.

[0003] The crushing process mainly involves processing plastic flakes or granules using cutting machines, crushers, and grinders to obtain the desired particles. Due to limitations in equipment precision, the particle size of the crushed plastic powder varies considerably. The particle size of the plastic powder has a significant impact on the performance of coatings. To maintain good coating performance, the crushed particles are usually sieved.

[0004] A utility model patent with application number 202420036220.9 discloses a plastic powder screening device that filters the product twice through a medium-pore filter and a fine-pore filter, and discharges the product through corresponding outlets. The patent also includes a cleaning plate and cleaning brushes to remove residual product from the box. However, the above patent has the following problems: 1. Both the medium-pore and fine-pore filters are horizontally arranged, and the movement trajectory of the cleaning plate and cleaning brushes is also horizontal. This only concentrates the residual product and cannot effectively discharge the product remaining in the box, still requiring manual assistance for removal; 2. Some residual product may be pressed into the mesh as the cleaning plate and cleaning brushes operate, causing mesh blockage or falling out of the mesh. The former affects subsequent screening functions, and the latter affects the quality of the screened product. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a plastic powder screening device with good screening effect and less residue after screening.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a plastic powder sieving device, comprising a sieving box, a rotating shaft, and two support seats disposed on both sides of the sieving box. The sieving box includes an inner cavity, the inner wall of which is formed by cylindrical side walls and two circular bottom walls disposed at both ends of the side walls, the two bottom walls being parallel to each other. The rotating shaft passes through the sieving box, and the axis of the rotating shaft coincides with the center line of the side walls. Both ends of the rotating shaft are rotatably connected to the two support seats respectively, and the heights of the two ends of the rotating shaft are the same. A motor for controlling the rotation of the rotating shaft is provided on the support seats, and a vibrator is provided on the rotating shaft. The screening box is equipped with a second vibrator. A guide plate and a mesh-like filter plate are fixed on the rotating shaft. The side of the guide plate facing away from the rotating shaft abuts against the side wall. The two sides of the guide plate adjacent to the rotating shaft abut against the two bottom walls respectively. The side wall is equipped with a feed inlet, a waste outlet, and a discharge outlet. The feed inlet is equipped with a first sealing door, and the waste outlet is equipped with a second sealing door. The discharge outlet is located at the lowest point of the side wall, and the height of the waste outlet is between the feed inlet and the discharge outlet.

[0007] The heights and height comparisons involved in the above scheme are all based on the ground surface in which the present invention is actually used.

[0008] In actual use, the crushed plastic powder enters the inner cavity through the feed inlet. At this time, the invention is in a filtering state, i.e., filter plate one is located between the feed inlet and the discharge outlet, guide plate is located between the feed inlet and the waste outlet and the guide plate is higher than filter plate one, and sealing door two is closed. The plastic powder entering the inner cavity falls onto filter plate one, and vibrators one and two are vibrating. After the amount of plastic powder entering the inner cavity reaches a predetermined value, sealing door one closes, and plastic powder that meets the particle size requirements falls from filter plate one and is collected and discharged from the discharge outlet. After vibration stops when no more plastic powder falls from the discharge outlet, the vibration stops, the motor drives the rotating shaft to rotate, the height of the side of filter plate one away from the rotating shaft increases, and the height of the side of guide plate away from the rotating shaft decreases until the guide plate is located between the discharge outlet and the waste outlet. At this time, the invention is in a cleaning state, i.e., filter plate one is higher than guide plate, and the height of the side of guide plate closer to the rotating shaft is greater than the height of the side of guide plate away from the rotating shaft. After the invention is in the cleaning state, the second sealing door is opened, and the first and second vibrators vibrate again. The plastic powder that does not meet the particle size requirements leaves the screening box from the waste port along the guide plate. The plastic powder collected from the waste port can be crushed again.

[0009] Compared with existing technologies, this invention can quickly screen out qualified plastic powder and quickly remove unqualified plastic powder from the inner cavity without leaving any residue or affecting subsequent screening.

[0010] As a further feature of the present invention, a second mesh-shaped filter plate is fixed on the rotating shaft. The side of the second filter plate facing away from the rotating shaft abuts against the side wall, and the two sides of the second filter plate adjacent to the rotating shaft abut against the two bottom walls respectively. The mesh size of the second filter plate is smaller than that of the first filter plate. A coarse material outlet is provided on the side wall, and a sealing door is provided at the coarse material outlet. The coarse material outlet is located between the inlet and the outlet, and the inlet is located between the waste outlet and the coarse material outlet.

[0011] Using the above scheme, sealing door one, sealing door two, and sealing door three can be connected to the screening box via threaded connection and opened and closed manually, or these three can be set as electric doors and opened and closed automatically by a program.

[0012] The second filter plate can perform secondary filtration on the plastic powder that has passed through the first filter plate. After a predetermined amount of plastic powder enters the inner cavity, the first, second, and third sealing doors are closed until no more plastic powder falls from the outlet. Then, the third sealing door opens, and under the action of the first and second vibrators, the residual plastic powder on the second filter plate leaves the inner cavity from the coarse material outlet. Plastic powder of different particle sizes can meet different needs. When the invention is in the filtration state, the second filter plate is located between the coarse material outlet and the outlet, and the first filter plate is located between the inlet and the coarse material outlet. The height of the side of the second filter plate closer to the rotating shaft is higher than the height of the side of the second filter plate farther from the rotating shaft.

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

[0014] By adopting the above solution, the side walls and bottom walls can be cleaned during the rotation of the shaft, preventing plastic powder from sticking to the side walls and bottom walls and ensuring the screening quality.

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

[0016] By adopting the above method, the filtration effect can be guaranteed.

[0017] As a further feature 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 solution prevents plastic powder from flying out of the gap between the rotating shaft and the screening box, external contaminants from entering the inner cavity through the gap, and plastic powder from getting stuck in the gap, thus ensuring the quality of the screened plastic powder.

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

[0020] As a further feature of the present invention, the sidewall is a drum shape that bulges outward from the center, the coarse material outlet, the discharge port and the waste material outlet are all located in the center of the sidewall, and the feed port is an elongated or rectangular hole extending along the axis of rotation.

[0021] In the above scheme, the middle section refers to the position where the distance from the side wall to the two bottom walls is equal. The shape of the side wall facilitates the concentration of plastic powder after primary screening towards the coarse material outlet, facilitates the concentration of plastic powder after secondary screening towards the discharge outlet, and facilitates the concentration of plastic powder with unqualified particle size towards the waste outlet. This improves screening efficiency and prevents plastic powder residue from remaining in the inner cavity. The shape of the feed inlet allows the plastic powder entering the inner cavity to be more evenly distributed on the filter plate. The oblong hole consists of two semicircles and a square between the two semicircles.

[0022] As a further feature of the present invention, an inspection port is provided on the side wall, an inspection door is provided on the inspection port, a sealing ring is provided on the inner wall of the inspection port, the inspection door is hinged to the screening box on the side at the higher position, and a protruding end is provided on the side at the lower position of the inspection door in the direction away from the rotating shaft. A fixed end is provided on the screening box at the position opposite to the protruding end, and the protruding end and the fixed end are fixed by bolts.

[0023] The above solution facilitates maintenance by providing access for staff, and preferably includes a transparent inspection window on the inspection door.

[0024] As a further feature of the present invention, the bottom of the screening box is provided with springs, and there are at least two springs arranged sequentially along the axial direction of the rotating shaft.

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

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

[0027] Using the above method, the crushed plastic powder may be loosely fixed together due to moisture, static electricity, etc. The crusher can pre-treat the crushed plastic powder to facilitate subsequent screening.

[0028] As a further feature of the present invention, the crusher includes a rotating shaft passing through a receiving groove, a plurality of blade groups arranged on the rotating shaft, and a drive component for controlling the rotation of the rotating shaft. All the blade groups are arranged sequentially along the axis of the rotating shaft. Each blade group 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-mentioned solution has a simple structure and a good crushing effect.

[0030] The present invention will now be further described with reference to the accompanying drawings. Attached Figure Description

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

[0032] Appendix Figure 2 This is a front view diagram illustrating actual use of a specific embodiment of the present invention;

[0033] Appendix Figure 3 For the appendix Figure 2 AA section view;

[0034] Appendix Figure 4 This is a cross-sectional view of the cleanup state in a specific embodiment of the present invention;

[0035] Appendix Figure 5 For the appendix Figure 4 Enlarged view of part B;

[0036] Appendix Figure 6 This is a schematic diagram of a guide plate, filter plate one, and filter plate two in a specific embodiment of the present invention.

[0037] Screening box 1, inner cavity 11, side wall 111, bottom wall 112, vibrator 2 12, feed inlet 13, waste outlet 14, discharge outlet 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 base 3, motor 31, guide plate 4, filter plate 1 5, filter plate 2 6, cleaning brush 7, sealing gasket 8, bearing 9, spring 10, receiving groove a1, rotating shaft a2, blade a3, driving component a4. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, it should be noted that, unless otherwise specified, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] Specific embodiments of the present invention, for example Figure 1-6 As shown.

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

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

[0043] The heights and height comparisons mentioned in this embodiment are based on the ground level during actual use. In this embodiment, sealing door 17, sealing door 2 18, and sealing door 3 19 are all electric doors, which are automatically controlled by a program.

[0044] In actual use, the crushed plastic powder enters the inner cavity 11 through the feed inlet 13. At this time, this embodiment is in the filtration state (see attached diagram). Figure 3 As shown in the diagram, filter plate 5 is located between the feed inlet 13 and the coarse material outlet 16, filter plate 6 is located between the coarse material outlet 16 and the discharge outlet 15, guide plate 4 is located between the feed inlet 13 and the waste outlet 14 and guide plate 4 is higher than filter plate 5, and the height of the side of filter plate 6 closer to the rotating shaft 2 is higher than the height of the side of filter plate 6 away from the rotating shaft 2. Sealing door 2 18 and sealing door 3 19 are in the closed state, and the plastic powder entering the inner cavity 11 falls onto filter plate 5. At this time, vibrator 1 21 and vibrator 2 12 are in the vibrating state. After the amount of plastic powder entering the inner cavity 11 reaches the predetermined value, sealing door 1 17 closes, and plastic powder that meets the particle size requirements falls from filter plate 5 onto filter plate 2 6. Filter plate 2 6 then performs a second filtration on the plastic powder filtered by filter plate 5, and the second-filtered plastic powder falls from the discharge outlet 15. After vibration continues until no more plastic powder falls from the discharge port 15, the sealing door 3 19 opens. Under the action of vibrator 1 21 and vibrator 2 12, the residual plastic powder on filter plate 2 6 leaves the inner cavity 11 from the coarse material outlet 16. Vibration stops and the sealing door 3 19 closes when no more plastic powder falls from the coarse material outlet 16. Motor 31 drives the rotating shaft 2 to rotate, raising the height of the side of filter plate 1 5 away from the rotating shaft 2, and lowering the height of the side of guide plate 4 away from the rotating shaft 2, until guide plate 4 is positioned between the discharge port 15 and the waste outlet 14. At this point, this embodiment is in the cleaning state (see attached diagram). Figure 4 As shown in the diagram, filter plate 5 is higher than guide plate 4, and the height of guide plate 4 on the side closer to the rotating shaft 2 is higher than the height of guide plate 4 on the side farther from the rotating shaft 2. In this embodiment, after the cleaning state, sealing door 18 is opened, vibrator 21 and vibrator 12 vibrate again, and plastic powder that does not meet the particle size requirements leaves the screening box 1 from the waste port 14 along guide plate 4. The plastic powder collected from the waste port 14 can be crushed again.

[0045] Compared to existing technologies, this embodiment can quickly screen out qualified plastic powder and quickly remove unqualified plastic powder from the inner cavity 11 without leaving any residue or affecting subsequent screening. Depending on the crushing volume of the crushing process, two or more embodiments of this embodiment can be set up. By staggering the screening time of each embodiment, continuous screening can be achieved.

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

[0047] In this embodiment, the included angle e between the guide plate 4 and the first filter plate 5 is 130°, and the included angle p between the first filter plate 5 and the second filter plate 6 is 60°. This ensures the filtration 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 ensures that the rotating shaft 2 remains sealed even when there is a small relative displacement between it and the screening box 1 during vibration. This prevents plastic powder in the inner cavity 11 from flying out from the gap between the rotating shaft 2 and the screening box 1, prevents external contaminants from entering the inner cavity 11 through the gap, and prevents plastic powder from getting stuck in the gap, thus ensuring the quality of the screened plastic powder.

[0049] The side wall 111 is a drum-shaped structure that bulges outward from the center. The coarse material outlet 16, the discharge outlet 15, and the waste outlet 14 are all located in the center of the side wall 111, where the distance from the side wall 111 to the two bottom walls 112 is equal. The feed inlet 13 is an elongated oval hole extending along the axis of the rotating shaft 2, consisting of two semicircles and a square between them. The shape of the side wall 111 facilitates the concentration of plastic powder after primary screening towards the coarse material outlet 16, the concentration of plastic powder after secondary screening towards the discharge outlet 15, and the concentration of plastic powder with unqualified particle size towards the waste outlet 14. This improves screening efficiency and prevents plastic powder residue in the inner cavity 11. The shape of the feed inlet 13 also allows the plastic powder entering the inner cavity 11 to be more evenly distributed on the filter plate 5.

[0050] A maintenance opening 1a is provided on the side wall 111, and a maintenance door 1b is provided on the maintenance opening 1a. A sealing ring is provided on the inner wall of the maintenance opening 1a. The side of the maintenance door 1b located at the higher position is hinged to the screening box 1. The side of the maintenance door 1b located at the lower position has a protruding end 1b1 that protrudes away from the rotating shaft 2. A fixed end 1c is provided on the screening box 1 at a position opposite to the protruding end 1b1. The protruding end 1b1 and the fixed end 1c are fixed by bolts. The maintenance opening 1a facilitates maintenance by personnel. In this embodiment, the maintenance door 1b is provided with a transparent maintenance window 1b2.

[0051] The bottom of the screening box 1 is equipped with springs 10, at least two of which are arranged sequentially along the axis of the rotating shaft 2. The springs 10 can prevent the screening box 1 from vibrating too much.

[0052] A funnel-shaped receiving trough a1 is provided at the discharge port 15. A rotating shaft a2 and a drive component a4 for controlling the rotation of the rotating shaft a2 are installed on the receiving trough a1. Multiple blade groups are provided on the rotating shaft a2. All blade groups are arranged sequentially along the axis of the rotating shaft a2. Each 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 moisture, static electricity, etc. The crusher can pre-treat the crushed plastic powder to facilitate subsequent screening.

[0053] This invention is not limited to the specific embodiments described above. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any simple changes or modifications made to the design structure and concept of this invention fall within the protection scope of this invention.

Claims

1. A plastic powder sieving device, comprising a sieving box, characterized in that: It also includes a rotating shaft and two support seats disposed on both sides of the screening box. The screening box includes an inner cavity, the inner wall of which is surrounded by a cylindrical side wall and two circular bottom walls disposed at both ends of the side wall. The two bottom walls are parallel to each other. The rotating shaft passes 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 two ends of the rotating shaft are at the same height. The support seats are equipped with a motor to control the rotation of the rotating shaft. A vibrator is disposed on the rotating shaft, and a vibrator is disposed on the screening box. A guide plate and a mesh-like filter plate are fixed on the rotating shaft. The side of the guide plate facing away from the rotating shaft abuts against the side wall. The guide plate has two surfaces adjacent to the rotating shaft that abut against the two bottom walls. The filter plate has one surface facing away from the rotating shaft that abuts against the side wall. The side wall has an inlet, a waste outlet, and an outlet. The inlet has a sealing door one, and the waste outlet has a sealing door two. The outlet is located at the lowest point of the side wall, and its height is between the inlet and outlet. A mesh filter plate two is fixed on the rotating shaft. The filter plate two has one surface facing away from the rotating shaft that abuts against the side wall, and two surfaces adjacent to the rotating shaft that abut against the two bottom walls. The mesh size of filter plate two is smaller than that of filter plate one. A coarse material outlet is provided on the side wall, and a sealing door three is provided at the coarse material outlet. The coarse material outlet is located between the inlet and outlet, and the inlet is located between the waste outlet and the coarse material outlet. Cleaning brushes are provided on the guide plate, filter plate one, and filter plate two facing the side wall and bottom wall, respectively. Filter plate one is located between the inlet and the coarse material outlet, and filter plate two is located between the coarse material outlet and the outlet. The guide plate is located between the inlet and the waste outlet and is higher than filter plate one. The height of the side of filter plate two closer to the rotating shaft is higher than the height of the side of filter plate two farther from the rotating shaft. When the second and third sealing doors are closed, it is in the filtration state; when the motor drives the rotating shaft to rotate, the height of the side of the filter plate 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 between the discharge port and the waste port. When the filter plate is higher than the guide plate, and the height of the side of the guide plate near the rotating shaft is higher than the height of the side of the guide plate away from the rotating shaft, it is in the cleaning state; the vibrators one and two vibrate in the filtration state and the cleaning state, and stop when switching between the filtration state and the cleaning state; the rotating shaft is stationary in the filtration state and the cleaning state, and the filtration state and the cleaning state are switched by rotating the rotating shaft.

2. The plastic powder screening device according to claim 1, characterized in that: There is an angle of 120° to 150° between the guide plate and the first filter plate, and an angle of 50° to 70° between the first filter plate and the second filter plate.

3. The plastic powder screening device according to claim 2, characterized in that: 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.

4. The plastic powder screening device according to claim 3, characterized in that: The sidewall is a drum shape that bulges outward from the center. The coarse material outlet, discharge port, and waste material outlet are all located in the middle of the sidewall. The feed inlet is an elongated or rectangular hole that extends along the axis of rotation.

5. The plastic powder screening device according to claim 4, characterized in that: The side wall is provided with an inspection port, the inspection port is provided with an inspection door, the inner wall of the inspection port is provided with a sealing ring, the side of the inspection door located at the higher position is hinged to the screening box, the side of the inspection door located at the lower position is provided with a protruding end that protrudes away from the rotating shaft, and the screening box is provided with a fixed end at a position opposite to the protruding end, the protruding end and the fixed end are fixed by bolts.

6. The plastic powder screening device according to claim 5, characterized in that: The bottom of the screening box is equipped with springs, and there are at least two springs arranged sequentially along the axis of the rotating shaft.

7. A plastic powder screening device according to claim 6, characterized in that: The discharge port is provided with a funnel-shaped receiving trough, and a crusher is installed inside the receiving trough.

8. A plastic powder screening device according to claim 7, characterized in that: The crusher includes a rotating shaft passing through a receiving trough, multiple blade groups arranged on the rotating shaft, and a drive component for controlling the rotation of the rotating shaft. All the blade groups are arranged sequentially along the axis of the rotating shaft. Each blade group 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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