Material screening device and screening method thereof

Abstract

The present invention relates to the technical field of material screening, and specifically to a material screening device and a screening method thereof, comprising a shell and a lower hopper arranged on the shell, a screen plate being arranged in the shell, and a power mechanism being arranged in the shell. A bucket-shaped screening plate corresponding to the lower part of the lower hopper is arranged on the screen plate, and an auxiliary plate is arranged at the lower end of the lower hopper, and a primary kneading gap is formed between the auxiliary plate and the upper surface of the bucket-shaped screening plate. The screen plate comprises a secondary screening plate distributed on one side of the bucket-shaped screening plate, an auxiliary conveyor belt is arranged above the secondary screening plate, and a U-shaped belt is formed on the lower conveyor belt of the auxiliary conveyor belt, and a secondary kneading gap is formed between the bottom surface of the U-shaped belt and the upper surface of the secondary screening plate, and a screening mechanism is arranged between two adjacent U-shaped belts on the secondary screening plate. The present invention can knead the grains when screening the grain materials, so that the impurities on the surface fall off, thereby improving the screening effect, and at the same time improving the screening and conveying efficiency of the grains, and reducing the accumulation and blockage phenomenon.

Description

Technical Field

[0001] The invention relates to the technical field of material screening, and in particular to a material screening device and a screening method thereof. Background Art

[0002] During the processing of grain materials, screening is usually required to remove impurities. After the grain is harvested, some shells or impurities may adhere to its surface for various reasons. These impurities may include husks, straw debris, dust and other substances. These impurities may have a negative impact on subsequent processing and utilization. Some impurities adhere tightly to the surface of the grain, forming a combination that is difficult to separate. Existing screening devices usually rely on mechanical vibration or airflow to separate grains from impurities. However, these screening devices are often limited in their effectiveness when faced with impurities that adhere tightly to the surface of the grain. Vibration may not be enough to overcome the adhesion between the impurities and the grain, and airflow may also be difficult to produce an effective separation effect due to the size, shape and adhesion position of the impurities.

[0003] In the prior art, a Chinese patent document with the announcement number CN115156023B discloses a grain cleaning and screening machine, including a screening plate, the outer surface of which is rotatably connected to a plurality of rotating shafts; each rotating shaft runs through the interior of a screening slot, and adjacent rotating shafts are connected by a belt; the surface of each rotating shaft and located inside each screening slot are fixedly connected to a guide wheel; the interior of each screening slot and located on both sides of the guide wheel are rotatably connected to conveying wheels. The soil is removed by friction rotation between the guide wheel and the conveying wheel, which is not convenient for removing the impurities on the surface of the material and is easy to damage the material. Summary of the invention

[0004] The invention provides a material screening device and a screening method thereof, so as to solve the technical problem in the prior art that when screening grain materials, shells, debris and the like on the surface are difficult to be screened out.

[0005] In order to solve the above problems, the present invention provides a material screening device and a screening method thereof adopting the following technical solutions:

[0006] A material screening device comprises a shell and a lower hopper arranged on the shell, a screen plate is arranged in the shell, and a power mechanism for driving the screen plate to screen forward and backward in a horizontal direction is also arranged in the shell.

[0007] The screen plate is provided with a bucket-shaped screening plate corresponding to the lower part of the lower hopper, and the lower end of the lower hopper is provided with an auxiliary plate, and a primary kneading gap is formed between the auxiliary plate and the upper surface of the bucket-shaped screening plate.

[0008] The screen plate includes a secondary screening plate distributed on one side of the bucket-shaped screening plate, an auxiliary conveyor belt is provided above the secondary screening plate, the lower conveyor belt of the auxiliary conveyor belt forms a U-shaped belt, and the U-shaped belts are multiple and arranged at intervals, and a secondary kneading gap is formed between the bottom surface of the U-shaped belt and the upper surface of the secondary screening plate, a screening mechanism is provided on the secondary screening plate between two adjacent U-shaped belts, and a discharge port is formed at one end of the secondary screening plate away from the bucket-shaped screening plate.

[0009] When the power mechanism drives the screen plate to sieve forward and backward, the material is kneaded and impurities are removed in the primary kneading gap and the secondary kneading gap.

[0010] By adopting the above technical scheme, through the primary kneading gap formed between the bucket-shaped screening plate and the auxiliary plate, and the secondary kneading gap formed between the U-shaped belt of the auxiliary conveyor belt and the secondary screening plate, the material can be kneaded multiple times during the screening process by the screen plate moving back and forth, thereby effectively removing impurities on the surface of the material and improving the screening efficiency.

[0011] Furthermore, the power mechanism includes a bent rod rotatably arranged in the shell, a support shaft is arranged below the screen plate, a connecting rod is arranged between the bent rod and the support shaft, and both ends of the connecting rod are provided with connecting sleeves for external movable connection.

[0012] A motor for driving the crankshaft to rotate is arranged on the outer wall of the shell.

[0013] Furthermore, a first connecting piece is hinged between the side plate on one side of the sieve plate and the inner wall of the shell, and a telescopic rod is hinged between the side plate on the other side of the sieve plate and the inner wall of the shell.

[0014] By adopting the above technical solution, the two ends of the connecting rod are movably sleeved on the curved rod and the support shaft respectively. While transmitting power, the connecting rod can also adapt to the slight changes of the screen plate during the screening process, thereby ensuring the stability and reliability of power transmission; the screen plate can realize forward and backward screening under the action of the connecting rod, and can more effectively separate impurities in the material.

[0015] Furthermore, the auxiliary conveyor belt includes a guide roller for forming a U-shaped belt, and a fixed plate fixed to the side wall of the shell is provided above the auxiliary conveyor belt. Side support plates are provided on the front and rear sides of the fixed plate, and the guide rollers corresponding to the side support plates are rotatably supported by the side support plates.

[0016] One end of the auxiliary conveyor belt is provided with a driving roller, and the driving roller is rotatably supported by a frame fixed on the shell, and a motor for driving the driving roller to rotate is provided on the frame.

[0017] Furthermore, the frame includes a transverse plate and vertical plates arranged at both ends of the transverse plate, the active roller and the guide rollers corresponding to the vertical plates are rotatably supported by the vertical plates, and the inner wall of the top plate of the shell is provided with pillars, which are fixed and penetrate the transverse plate.

[0018] By adopting the above technical solution, the auxiliary conveyor belt structure support is stable, and the auxiliary conveyor belt can run stably, ensuring that the material is fully kneaded in the secondary kneading gap, thereby effectively removing impurities, and also assisting the material to be transported more stably and smoothly.

[0019] Furthermore, the screening mechanism includes a slot arranged on the secondary screening plate, a strip plate is arranged in the slot, a vibration component for driving the strip plate to vibrate vertically is arranged on the strip plate, partitions for slidingly cooperating with the strip plate are arranged on the left and right sides of the slot, and sieve holes are formed between adjacent partitions.

[0020] Further, the vibration assembly includes a guide column arranged on the upper surface of the strip plate, the guide column vertically penetrates the fixed plate and is fixedly connected to the vibration plate arranged above the fixed plate in the air, a spring is sleeved on the guide column and is located between the fixed plate and the vibration plate, a convex block is arranged above the vibration plate, and a convex strip is arranged on the inner wall of the top plate of the shell, and the convex block drives the guide column to move vertically when passing through the convex strip horizontally;

[0021] The fixing plate is provided with an elongated slot hole for allowing the guide column to pass through, and the width of the elongated slot hole is greater than the diameter of the spring.

[0022] Furthermore, the secondary screening plate is provided with a guide plate which assists in guiding the materials to the slot.

[0023] By adopting the above technical solution, through the vertical vibration of the strip plate in the slot and the sieve holes formed between adjacent partitions, the material can be further finely screened on the secondary screening plate, effectively removing finer impurities and improving material effect and efficiency.

[0024] Furthermore, a miscellaneous material box is provided below the screen plate.

[0025] By adopting the above technical solution, a dust suction pipe extending out of the shell is provided on one side of the debris box, and debris in the debris box is sucked out by negative pressure, thereby improving the debris collection efficiency.

[0026] A material screening method, using the above-mentioned material screening device, comprises the following steps:

[0027] First, start the power mechanism and drive the screen plate to move back and forth through the power mechanism, then put the material to be screened from the lower hopper into the shell, the material is first screened by the bucket-shaped screening plate, and at the same time, the material is kneaded in the first kneading gap to remove surface impurities, then the material enters the bucket-shaped screening plate, and while being assisted by the auxiliary conveyor belt, the material is kneaded again in the second kneading gap to remove impurities, after the screening is completed, the material can be discharged from the discharge port.

[0028] By adopting the above technical solution, when screening the grain materials, the grains can be kneaded to remove impurities on their surfaces, thereby improving the screening effect.

[0029] The beneficial effects of the present invention are as follows: through the primary kneading gap formed between the bucket-shaped screening plate and the auxiliary plate, and the secondary kneading gap formed between the U-shaped belt of the auxiliary conveyor belt and the secondary screening plate, the material can be kneaded multiple times during the screening process, thereby effectively removing impurities on the surface of the material and improving the screening effect and efficiency; when the material is screened on the secondary screening plate, the conveying efficiency is high and accumulation and clogging are not likely to occur, which helps to improve the screening efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0031] Figure 1 It is a structural schematic diagram of the material screening device of the present invention;

[0032] Figure 2 It is a schematic diagram of the internal structure of the material screening device of the present invention;

[0033] Figure 3 It is a structural schematic diagram of the power mechanism in the present invention;

[0034] Figure 4 It is a cross-sectional structural schematic diagram of the material screening device of the present invention;

[0035] Figure 5 for Figure 4 A partial enlarged view of the middle area A;

[0036] Figure 6 for Figure 4 A partial enlarged view of the middle area B;

[0037] Figure 7 for Figure 4 A partial enlarged view of the middle area C;

[0038] Figure 8 This is one of the partial structural cross-sectional views of the material screening device of the present invention;

[0039] Fig. 9 is a top view of the fixing plate in the present invention;

[0040] Fig.10 The second partial structural cross-sectional view of the material screening device of the present invention.

[0041] Description of reference numerals:

[0042] 1. Shell; 11. Lower hopper; 111. Auxiliary plate; 12. Fixed plate; 121. Side support plate; 120. Long slot hole; 13. Frame; 131. Horizontal plate; 132. Vertical plate; 14. Pillar; 15. Raised strip; 2. Screen plate; 20. Screening mechanism; 201. Notch; 202. Strip plate; 203. Partition plate; 204. Screen hole; 21. Bucket-shaped screening plate; 22. Secondary screening plate; 23. First connecting piece; 24. Telescopic rod; 25. Vibration assembly; 251. Guide column; 252. Vibration plate; 2521. Bump; 253. Spring; 26. Guide plate; 27. Miscellaneous material box; 3. Power mechanism; 31. Bending rod; 32. Support shaft; 33. Linking rod; 331. Connecting sleeve; 4. Auxiliary conveyor belt; 41. U-shaped belt; 42. Guide roller; 43. Active roller. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0044] Any number of elements in the drawings is for illustration and not limitation, and any naming is for distinction only and does not have any limiting meaning.

[0045] The principle and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0046] Embodiments of a material screening device and screening method provided by the present invention:

[0047] like Figures 1 to 10 As shown, a material screening device includes a shell 1 and a lower hopper 11 arranged on the shell 1, a screen plate 2 is arranged in the shell 1, and a power mechanism 3 for driving the screen plate 2 to screen back and forth in a horizontal direction is also arranged in the shell 1.

[0048] In this embodiment, the power mechanism 3 includes a curved rod 31 rotatably arranged in the shell 1, a support shaft 32 is provided below the screen plate 2, a connecting rod 33 is provided between the curved rod 31 and the support shaft 32, and both ends of the connecting rod 33 are provided with connecting sleeves 331 for external movable connection.

[0049] A motor for driving the crankshaft 31 to rotate is disposed on the outer wall of the housing 1 .

[0050] When the motor drives the crankshaft 31 to rotate, the sieve plate 2 is driven to move forward and backward through the connecting rod 33 due to the design of the eccentric part of the crankshaft 31 to achieve sieving.

[0051] Among them, a first connecting member 23 is hinged between the side plate on one side of the sieve plate 2 and the inner wall of the shell 1, and a telescopic rod 24 is hinged between the side plate on the other side of the sieve plate 2 and the inner wall of the shell 1.

[0052] The flexible forward and backward sieving movement of the sieve plate 2 is achieved by means of the hinged first connecting member 23 in cooperation with the hinged telescopic rod 24 .

[0053] A bucket-shaped screening plate 21 corresponding to the lower part of the lower hopper 11 is provided on the screen plate 2 . An auxiliary plate 111 is provided at the lower end of the lower hopper 11 . A primary kneading gap is formed between the auxiliary plate 111 and the upper surface of the bucket-shaped screening plate 21 .

[0054] The material to be screened enters the shell 1 from the lower hopper 11 and is scattered on the bucket-shaped screening plate 21. Since a primary kneading gap is formed between the auxiliary plate 111 and the upper surface of the bucket-shaped screening plate 21, when the material is scattered on the surface of the bucket-shaped screening plate 21, the bucket-shaped screening plate 21 will knead and remove impurities on the grain material in cooperation with the auxiliary plate 111 during the process of screening forward and backward movement of the screen plate 2, so that some surface impurities on the surface of the grain material fall off, and the removed fine impurities will fall under the bucket-shaped screening plate 21. The grain material is dispersed and falls through the action of the bucket-shaped screening plate 21, and is screened by the screen plate 2, and the material gradually enters the secondary screening plate 22.

[0055] The screen plate 2 includes a secondary screening plate 22 distributed on one side of the bucket-shaped screening plate 21. An auxiliary conveyor belt 4 is provided above the secondary screening plate 22. The lower conveyor belt of the auxiliary conveyor belt 4 forms a U-shaped belt 41. There are four U-shaped belts 41 arranged at intervals. A secondary kneading gap is formed between the bottom surface of the U-shaped belt 41 and the upper surface of the secondary screening plate 22. A screening mechanism 20 is provided on the secondary screening plate 22 and is located between two adjacent U-shaped belts 41. A discharge port is formed at one end of the secondary screening plate 22 away from the bucket-shaped screening plate 21.

[0056] Among them, the auxiliary conveyor belt 4 includes a guide roller 42 for forming a U-shaped belt 41. A fixed plate 12 fixed on the side wall of the shell 1 is provided above the auxiliary conveyor belt 4. Side support plates 121 are provided on the front and rear sides of the fixed plate 12. The guide roller 42 corresponding to the side support plate 121 is rotatably supported by the side support plate 121.

[0057] A driving roller 43 is provided at one end of the auxiliary conveyor belt 4 . The driving roller 43 is rotatably supported by a frame 13 fixed on the housing 1 , and a motor for driving the driving roller 43 to rotate is provided on the frame 13 .

[0058] Among them, the frame 13 includes a horizontal plate 131 and vertical plates 132 arranged at both ends of the horizontal plate 131, the active roller 43 and the guide roller 42 corresponding to the vertical plate 132 are both rotatably supported by the vertical plate 132, and the inner wall of the top plate of the shell 1 is provided with a pillar 14, which is fixed through the horizontal plate 131.

[0059] After the grain material enters the secondary screening plate 22, it will enter the secondary kneading gap as it gradually moves forward. The auxiliary conveyor belt 4 drives and conveys counterclockwise, thereby auxiliary conveying the grain material while the grain material is kneaded and impurities are removed again in the secondary kneading gap. When the material enters the screening mechanism 20, impurities will fall from the screening mechanism 20.

[0060] In this embodiment, the screening mechanism 20 includes a slot 201 provided on the secondary screening plate 22, a strip plate 202 is provided in the slot 201, a vibration assembly 25 is provided on the strip plate 202 for driving the strip plate 202 to vibrate vertically, partitions 203 are provided on the left and right sides of the slot 201 for slidingly cooperating with the strip plate 202, and sieve holes 204 are formed between adjacent partitions 203.

[0061] Specifically, both sides of the strip plate 202 are provided with slots corresponding to the partition plate 203, and the partition plate 203 slides in the slots and enables the strip plate 202 to move vertically.

[0062] Among them, the vibration assembly 25 includes a guide column 251 arranged on the upper surface of the strip plate 202, and each guide column 251 on the strip plate 202 is distributed at both ends. The guide column 251 is located on the side of the auxiliary conveyor belt 4 and vertically penetrates the fixed plate 12 and is fixedly connected to the vibration plate 252 arranged above the fixed plate 12 in the air. The guide column 251 is sleeved with a spring 253 located between the fixed plate 12 and the vibration plate 252, and a protrusion 2521 is provided above the vibration plate 252. The inner wall of the top plate of the shell 1 is provided with a convex strip 15. When the protrusion 2521 passes through the convex strip 15 horizontally, it drives the guide column 251 to move vertically.

[0063] The upper surface of the protrusion 2521 and the lower surface of the protrusion 15 are both arc-shaped.

[0064] The fixing plate 12 is provided with an elongated slot hole 120 for allowing the guide pillar 251 to pass through, and the width of the elongated slot hole 120 is greater than the diameter of the spring 253 .

[0065] The secondary screening plate 22 is provided with a guide plate 26 for assisting in centrally guiding the materials to the slot 201. Specifically, the guide plates 26 are arranged in multiple groups at intervals, and each group includes two guide plates 26, and the two guide plates 26 are arranged in an eight-shaped shape.

[0066] When the grain material is transported to the screening mechanism 20, it will be guided to the notch 201 through the figure eight distribution guide plate 26, and will pass through the sieve hole 204, and the debris generated by rubbing will be screened out and fall.

[0067] Specifically, the secondary screening plate 22 will push the strip plate 202 to move forward and backward during the screening process. The forward and backward movement of the strip plate 202 will drive the guide column 251 to move forward and backward, and drive the vibration plate 252 to move. During the movement of the vibration plate 252, the protrusion 2521 and the protrusion 15 will contact or disengage, so that the vibration plate 252 will vibrate vertically, and finally the strip plate 202 will vibrate vertically, so that the debris at the screen hole 204 is easier to fall down, and the problem of blockage of the screen hole 204 is effectively alleviated.

[0068] In this embodiment, a miscellaneous material box 27 is provided below the screen plate 2 .

[0069] Specifically, the screen plate 2 is provided with a through opening corresponding to the bottom of the bucket-shaped screening plate 21 , and debris dropped from the bucket-shaped screening plate 21 will enter the debris box 27 through the through opening.

[0070] Among them, a dust suction pipe extending out of the shell 1 is provided on one side of the sundry material box 27, and the debris in the sundry material box 27 is sucked out by the negative pressure.

[0071] A material screening method, using the above-mentioned material screening device, comprises the following steps:

[0072] First, start the power mechanism 3 and drive the screen plate 2 to sieve forward and backward through the power mechanism 3, then put the material to be screened from the lower hopper 11 into the shell 1, the material is first screened through the bucket-shaped screening plate 21, and at the same time, the material is kneaded in the first kneading gap to remove surface impurities, and then the material enters the bucket-shaped screening plate 21, and while being assisted by the auxiliary conveyor belt 4, the material is kneaded again in the second kneading gap to remove impurities. After the screening is completed, the material can be discharged from the discharge port.

[0073] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "width", "horizontal", "top", "bottom", "inside", "outside" and the like, which indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the drawings of this specification, and are only for the purpose of facilitating the explanation of the scheme of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the devices or elements involved must have the specific orientation, be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as limitations on the scheme of the present invention.

[0074] In addition, in the description of this specification, “plurality” means at least two, for example, two, three or more, etc., unless otherwise clearly and specifically defined.

Claims

1. A material screening device, comprising a housing (1) and a lower hopper (11) arranged on the housing (1), wherein a sieve plate (2) is arranged in the housing (1), characterized in that: The housing (1) is also provided with a power mechanism (3) for driving the screen plate (2) to sieve forward and backward in a horizontal direction; The sieve plate (2) is provided with a bucket-shaped screening plate (21) corresponding to the lower part of the lower hopper (11); an auxiliary plate (111) is provided at the lower end of the lower hopper (11); a primary kneading gap is formed between the auxiliary plate (111) and the upper surface of the bucket-shaped screening plate (21); The sieve plate (2) comprises a secondary screening plate (22) distributed on one side of the bucket-shaped screening plate (21); an auxiliary conveyor belt (4) is provided above the secondary screening plate (22); a lower conveyor belt of the auxiliary conveyor belt (4) is formed with a U-shaped belt (41); a plurality of U-shaped belts (41) are arranged at intervals; a secondary kneading gap is formed between the bottom surface of the U-shaped belt (41) and the upper surface of the secondary screening plate (22); a screening mechanism (20) is provided on the secondary screening plate (22) between two adjacent U-shaped belts (41); and a discharge port is formed at one end of the secondary screening plate (22) away from the bucket-shaped screening plate (21); When the power mechanism (3) drives the screen plate (2) to sieve forward and backward, the material is kneaded and impurities are removed in the primary kneading gap and the secondary kneading gap.

2. The material screening device according to claim 1, characterized in that: The power mechanism (3) comprises a bent rod (31) rotatably arranged in the housing (1); a support shaft (32) is provided below the screen plate (2); a connecting rod (33) is provided between the bent rod (31) and the support shaft (32); and connecting sleeves (331) movably connected to the outside are provided at both ends of the connecting rod (33); A motor for driving the curved rod (31) to rotate is provided on the outer wall of the housing (1).

3. The material screening device according to claim 2, characterized in that: A first connecting member (23) is hingedly connected between the side plate on one side of the sieve plate (2) and the inner wall of the shell (1), and a telescopic rod (24) is hingedly connected between the side plate on the other side of the sieve plate (2) and the inner wall of the shell (1).

4. The material screening device according to claim 1, characterized in that: The auxiliary conveyor belt (4) comprises a guide roller (42) for forming a U-shaped belt (41); a fixing plate (12) fixed to a side wall of the shell (1) is provided above the auxiliary conveyor belt (4); side support plates (121) are provided on both the front and rear sides of the fixing plate (12); and the guide roller (42) corresponding to the side support plate (121) is rotatably supported by the side support plate (121); A driving roller (43) is provided at one end of the auxiliary conveyor belt (4), and the driving roller (43) is rotatably supported by a frame (13) fixed on the housing (1), and a motor for driving the driving roller (43) to rotate is provided on the frame (13).

5. The material screening device according to claim 4, characterized in that: The frame (13) comprises a transverse plate (131) and vertical plates (132) arranged at both ends of the transverse plate (131); the active roller (43) and the guide roller (42) corresponding to the vertical plate (132) are both rotatably supported by the vertical plate (132); a support column (14) is provided on the inner wall of the top plate of the shell (1); the support column (14) is fixedly passed through the transverse plate (131).

6. The material screening device according to claim 4, characterized in that: The screening mechanism (20) comprises a notch (201) provided on a secondary screening plate (22), a strip plate (202) being provided in the notch (201), a vibration assembly (25) being provided on the strip plate (202) for driving the strip plate (202) to vibrate vertically, partition plates (203) being provided on both left and right sides of the notch (201) for slidingly cooperating with the strip plate (202), and sieve holes (204) being formed between adjacent partition plates (203).

7. The material screening device according to claim 6, characterized in that: The vibration assembly (25) comprises a guide column (251) arranged on the upper surface of the strip plate (202), the guide column (251) vertically penetrates the fixed plate (12) and is fixedly connected to a vibration plate (252) arranged above the fixed plate (12) in the air, the guide column (251) is sleeved with a spring (253) between the fixed plate (12) and the vibration plate (252), a convex block (2521) is arranged above the vibration plate (252), a convex strip (15) is arranged on the inner wall of the top plate of the housing (1), and the convex block (2521) drives the guide column (251) to move vertically when passing through the convex strip (15) horizontally; The fixing plate (12) is provided with an elongated slot hole (120) that allows the guide column (251) to pass through, and the width of the elongated slot hole (120) is greater than the diameter of the spring (253).

8. The material screening device according to claim 6, characterized in that: The secondary screening plate (22) is provided with a guide plate (26) for assisting in centrally guiding the materials to the slot (201).

9. The material screening device according to claim 1, characterized in that: A miscellaneous material box (27) is provided below the screen plate (2).

10. A material screening method, characterized in that: The material screening device according to claim 1 comprises the following steps: First, the power mechanism (3) is started and the screen plate (2) is driven by the power mechanism (3) to sieve forward and backward. Then, the material to be screened is put into the housing (1) from the lower hopper (11). The material is first screened by the bucket-shaped screening plate (21). At the same time, the material is kneaded in the primary kneading gap to remove surface impurities. Then, the material enters the bucket-shaped screening plate (21). While being assisted by the auxiliary conveyor belt (4), the material is kneaded again in the secondary kneading gap to remove impurities. After the screening is completed, the material can be discharged from the discharge port.

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