A sorting device and method for grain processing

Abstract

The application provides a sorting device and method for grain processing, and relates to the technical field of grain processing equipment. The sorting device for grain processing comprises a sorting table, a screening table, a dust removal table and a discharging table. The dust removal table is arranged above the screening table, the discharging table is arranged above the dust removal table, a servo motor one is fixedly connected to the right end outer wall of the discharging table, a reciprocating screw rod two is fixedly connected to the driving end of the servo motor one, a discharging plate is connected to the outer wall of the reciprocating screw rod two through an adapter, the discharging plate is slidingly connected to the inner wall of the discharging table, a winnowing bin is fixedly connected to the inner wall of the dust removal table, and a fan is fixedly connected to the rear end of the dust removal table. Through four-stage integrated collection of gap discharging, spiral dust removal, three-layer deflection screening and double-column series dielectric sorting, the comprehensive effects of uniform grain dispersion, efficient dust removal, continuous screening and fine classification and sorting are realized.

Description

Technical Field

[0001] This invention relates to the field of grain processing equipment technology, specifically to a grain sorting device and method. Background Technology

[0002] Grain sorting is a crucial step in grain processing. Its purpose is to remove various impurities from grains (such as straw, husks, stones, dust, shriveled grains, and moldy grains) and grade them according to grain size or quality to improve the cleanliness and commercial value of the grains. Existing grain sorting technologies mainly include air separation, screening, gravity separation, and color sorting. However, each type of sorting equipment has varying degrees of technical shortcomings in practical applications.

[0003] The first drawback of existing technology lies in its unreasonable feeding method. Traditional sorting equipment often uses a straight-through hopper for direct feeding. Grains accumulate and fall rapidly under gravity, easily forming material clumps. This leads to uneven feeding in subsequent sorting units, large fluctuations in material layer thickness, and directly affects the effectiveness of air separation and screening. Material clumping also causes light impurities to be trapped inside the material, making effective separation impossible and reducing sorting accuracy.

[0004] The second drawback of existing technology is its low dust removal efficiency and incomplete dust separation. Traditional air separation equipment often uses simple vertical or horizontal air duct structures, resulting in uneven airflow distribution, short contact time between grains and airflow, and difficulty in fully separating light impurities and dust. At the same time, traditional air separation equipment lacks effective dust collection methods, and the separated dust is prone to secondary re-entrainment, which not only pollutes the working environment but also harms the health of operators.

[0005] The third drawback of existing technology lies in its limited screening methods, susceptibility to screen clogging, and difficulty in removing impurities. Traditional vibrating screens employ a fixed screen structure, making the screen openings prone to clogging by fine particles or fibrous impurities, resulting in a gradual reduction in the effective screening area. Furthermore, the fixed screen angle and aperture of traditional screening equipment cannot be flexibly adjusted according to material characteristics, making it difficult to achieve efficient classification of impurities of different particle sizes. The trapped impurities require manual cleaning after machine shutdown, which is not only inefficient but also disrupts continuous production.

[0006] The fourth drawback of existing technologies lies in insufficient sorting accuracy and limited sorting dimensions. Traditional sorting equipment mostly employs gravity sorting or color sorting. Gravity sorting equipment has a complex structure, numerous adjustment parameters, and requires highly experienced operators. While color sorting equipment offers higher accuracy, it is expensive, bulky, and consumes a lot of energy per unit of processing time. Furthermore, its ability to identify impurities with similar shapes but similar colors is limited. In addition, the sorting rollers in existing sorting equipment mostly use a single cylindrical structure, resulting in poor uniformity of electric field distribution. This makes it difficult to effectively separate particles with small differences in dielectric constant, and the sorting accuracy needs further improvement. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a sorting device and method for grain processing, which solves the problems commonly found in traditional grain sorting equipment, such as uneven feeding leading to clumping, incomplete dust removal causing dust to fly away, easy clogging of screens making it difficult to remove impurities, and insufficient sorting precision.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a grain processing sorting device, comprising a sorting table, a screening table, a dust removal table, and a feeding table. The dust removal platform is positioned above the screening platform, and the material feeding platform is positioned above the dust removal platform. A servo motor is fixedly connected to the outer wall of the right end of the unloading platform. A reciprocating lead screw is fixedly connected to the drive end of the servo motor. A unloading plate is connected to the outer wall of the reciprocating lead screw through an adapter. The unloading plate is slidably connected to the inner wall of the unloading platform. The dust removal platform has an air separation chamber fixedly connected to its inner wall, a fan fixedly connected to its rear end, a spiral shell fixedly connected to the inner wall of the air separation chamber, and an exhaust shell provided on the outer wall of the right end of the air separation chamber. The inner wall of the screening table is fixedly connected to a screening shell, and the inner wall of the screening shell is rotatably connected to several screening screens. A hydraulic press is provided on the left side of the screening shell. A frustum-shaped separation column is rotatably connected to the front end of the inner wall of the sorting table, and an annular separation column is rotatably connected to the rear end of the inner wall of the sorting table. A high-voltage electrostatic generator is provided on the inner side of the frustum-shaped separation column and the annular separation column.

[0009] Preferably, a material feeding gap is left between the bottom of the feeding plate and the inner bottom wall of the feeding platform, and the width of the material feeding gap is 5mm to 15mm; The bottom of the unloading platform is provided with an unloading pipe, the upper end of which is connected to the inner cavity of the unloading platform, and the lower end of which extends into the interior of the spiral shell. The first servo motor is a stepper motor, which drives the second reciprocating lead screw to rotate through forward and reverse rotation, thereby causing the feeding plate to move in a reciprocating linear motion along the inner wall of the feeding table. Each time the feeding plate completes one reciprocating motion, it achieves one intermittent feeding, with a feeding frequency of 10 to 30 times per minute.

[0010] Preferably, a servo motor five is fixedly connected to the top left side of the air separator, a worm gear one is fixedly connected to the drive end of the servo motor five, a conical shell is provided on the central axis of the air separator, a worm wheel one is fixedly connected to the upper end of the conical shell, and the worm gear one and the worm wheel one mesh to form a worm wheel and worm gear assembly one. The first output end of the fan is connected to the lower part of the air separator via a duct, and the second output end is connected to the exhaust casing via a duct. The spiral shell descends along the inner wall of the air separation chamber in a spiral manner, with 3 to 5 spiral turns and a spiral angle of 10° to 20°.

[0011] Preferably, the screening mesh includes an upper screening mesh group, a middle screening mesh group and a lower screening mesh group, each screening mesh group is composed of multiple parallel rollers, and the spacing between each roller decreases from top to bottom; The drive end of the hydraulic press is fixedly connected to a drive gear plate, and the left end of each screening screen is fixedly connected to a transmission gear. The drive gear plate meshes with each transmission gear. A servo motor four is provided on the front left side of the inner wall of the screening shell, and a hydraulic press one is provided on the rear left side of the inner wall of the screening shell. A transmission rod is fixedly connected to the drive end of the servo motor four, and a connecting plate is fixedly connected to the drive end of the hydraulic press one. The transmission rod is connected to the upper screening mesh group and the lower screening mesh group through a worm gear set two, and the connecting plate is connected to the middle screening mesh group through a worm gear set two. A dust removal platform is fixedly connected to the rear side of the inner wall of the screening shell. The dust removal platform penetrates the rear wall of the screening shell and extends to the outer side of the screening platform. The bottom of the inner wall of the screening table is provided with a support shell, and the screening shell is fixedly installed on top of the support shell.

[0012] Preferably, the frustum-shaped separating column has a frustum-shaped structure with the diameter of the column gradually increasing from the left end to the right end and the taper is 5° to 10°; the annular separating column has a cylindrical structure with a uniform diameter. A second servo motor is fixedly connected to the rear right side of the sorting station. An active conveyor wheel is fixedly connected to the drive end of the second servo motor. A driven conveyor wheel is fixedly connected to the right end of the frustum separation column and the right end of the annular separation column. The active conveyor wheel is connected to the two driven conveyor wheels via a conveyor belt. The output voltage of the high-voltage electrostatic generator is 15kV to 30kV, and it is electrically connected to the metal columns of the frustum separation column and the annular separation column, respectively.

[0013] Preferably, a front cleaning frame and a rear cleaning frame are rotatably connected to the central axis on the left and right sides of the inner wall of the sorting table, a servo motor three is fixedly connected to the front left side of the sorting table, an active conveyor wheel two is fixedly connected to the drive end of the servo motor three, and a driven conveyor wheel two is fixedly connected to the left end of the front cleaning frame and the rear cleaning frame, respectively. The active conveyor wheel two and the two driven conveyor wheels two are connected by a conveyor belt two. The servo motor 3 has a worm gear 3 sleeved on the outer side of its drive end. The sorting table has a reciprocating screw 1 rotatably connected to the left side of its inner wall. The left end of the reciprocating screw 1 is fixedly connected to a worm wheel 3. The worm gear 3 and the worm wheel 3 mesh to form a worm wheel and worm gear assembly 3. The outer wall of the reciprocating lead screw is fitted with a connecting platform, and the inner wall of the connecting platform is rotatably connected to a cleaning wheel. The left end of the cleaning wheel is fixedly connected to a driven gear, and the left end of the inner wall of the sorting platform is fixedly connected to a driven toothed plate. The driven gear meshes with the driven toothed plate.

[0014] Preferably, it also includes an intelligent control unit, which is electrically connected to servo motor one, fan, servo motor five, hydraulic press two, servo motor four, hydraulic press one, servo motor two, servo motor three and high voltage electrostatic generator respectively; The intelligent control unit has a built-in preset parameter library for various grain varieties. By receiving detection signals from various sensors, it automatically adjusts the operating parameters of each driving component to achieve fully automated sorting control.

[0015] A grain sorting method for grain processing includes the following steps: Step S1, Intermittent feeding: The grains to be sorted are fed into the feeding table. The servo motor drives the feeding plate to reciprocate, so that the grains fall evenly and intermittently into the feeding pipe through the feeding gap at the bottom of the feeding plate, and then enter the dust removal table. Step S2, Spiral Dust Removal: After the grain enters the air separation chamber, it slides down the spiral shell in a spiral trajectory. The fan introduces high-speed airflow into the air separation chamber to form a spiral wind field, which separates the dust and light impurities in the grain and discharges them through the exhaust shell. Step S3, Roller Screening: After dust removal, the grains fall into the screening shell. The three-layer screening mesh group classifies and screens the grains. The upper screening mesh group intercepts large particles of impurities, the middle screening mesh group retains normal grains, and the lower screening mesh group intercepts fine sand and gravel. The hydraulic press drives the screening mesh to deflect, causing impurities to fall into the dust discharge platform and be discharged. Step S4, Dielectric Sorting: After screening, normal grains fall into the sorting table. The high-voltage electrostatic generator creates a high-voltage electrostatic field on the surface of the frustum separation column and the annular separation column. Particles with different dielectric properties are subjected to different polarization forces, resulting in different motion trajectories. The materials are diverted to different channels through the front cleaning frame and the rear cleaning frame to complete the fine selection.

[0016] Preferably, in step S2, the airflow velocity from the first output end of the fan to the lower part of the air separator is 8m / s to 15m / s, and the airflow forms an upward spiral flow field along the spiral shell. Servo motor five drives the conical shell to rotate through worm gear assembly one, with a speed of 30r / min to 60r / min. The conical shell drives the auxiliary blades to rotate, which enhances the stability of the spiral flow field. The second output end of the fan generates negative pressure to extract the separated dust through the exhaust shell.

[0017] Preferably, in step S3, the hydraulic press II drives the transmission gears of each screening screen to rotate through the drive tooth plate, causing the screening screen to deflect, with the deflection angle ranging from 0° to 30°. Servo motor four drives the upper and lower screening screen groups to rotate via worm gear set two at a speed of 50r / min to 100r / min. Hydraulic press one drives the middle screening screen group to rotate via worm gear set two at a speed of 30r / min to 60r / min. Large particles of impurities trapped by the upper screening screen group and fine sand and gravel intercepted by the lower screening screen group fall into the dust discharge platform and are then transported to the outside of the screening platform for discharge. In step S4, the frustum separation column has a frustum-shaped structure. The material enters from the left end with a smaller diameter and moves to the right along the column surface. The electric field strength gradually changes, realizing progressive grading and sorting. The annular separation column has a cylindrical structure and performs secondary fine selection on the normal grains output from the frustum separation column. Servo motor three drives reciprocating screw one to rotate through worm gear set three, which drives the connecting table to move axially. The cleaning wheel on the connecting table rotates under the meshing action of driven gear and driven tooth plate, and evenly conveys the material screened by the annular separation column to the frustum separation column.

[0018] Working principle: The grain sorting process is carried out in four stages in sequence: intermittent feeding, spiral dust removal, roller screening, and dielectric sorting. Each stage is progressive and coordinated to achieve fine grading and sorting of grains.

[0019] After the grains to be sorted enter the feeding platform, servo motor one drives reciprocating screw two to rotate, converting the rotational motion into linear motion through a ball bearing nut pair, causing the feeding plate to reciprocate linearly along the inner wall of the feeding platform. When the feeding plate moves forward, it pushes the grains in front forward, and the grains fall evenly through the feeding gap between the bottom of the feeding plate and the inner bottom wall; when the feeding plate moves backward, the grains behind replenish the position in front under the action of gravity. Each reciprocating motion of the feeding plate completes one intermittent feeding cycle. By controlling the frequency and stroke of the reciprocating motion, the feeding amount and feeding speed can be precisely adjusted. This intermittent feeding method can effectively break up material clumps, allowing the grains to continuously enter the subsequent sorting units in a uniform thin layer, avoiding the problems of material accumulation, clumping, and uneven feeding that are prone to occur in traditional straight-through feeding, and creating stable feeding conditions for subsequent air separation and screening processes.

[0020] After being fed through intermittent feeding, the grain enters the air separator chamber and slides downwards along the spiral channel of the spiral shell in a spiral trajectory. The first output end of the blower sends a high-speed airflow into the lower part of the air separator chamber. Guided by the spiral shell, the airflow forms a stable upward spiral flow field, creating a counter-current contact with the downward-sliding grain. During the spiral descent, the grain maintains continuous and sufficient contact with the upward airflow, significantly extending the contact time compared to traditional vertical air separators. Light impurities and dust accumulate towards the center of the chamber under the lift of the airflow and move upwards with it. A servo motor drives the conical shell to rotate after being reduced in speed by a worm gear assembly. The spiral auxiliary blades on the outer wall of the conical shell rotate synchronously, further enhancing the stability and uniformity of the spiral flow field, preventing turbulence and short-circuiting, and ensuring a uniform airflow distribution throughout the chamber. The second output end of the blower creates a negative pressure at the exhaust shell, drawing out the dust and light impurities accumulated at the top and transporting them to an external receiving and collecting device for centralized processing. This stage can efficiently remove light impurities such as dust, husks, awns, and shriveled grains from grains. At the same time, due to the uniformity of the spiral flow field, the airflow loss rate of normal grains is extremely low.

[0021] After dust removal, the grain falls into the screening shell, first reaching the upper screening screen group. Each screening screen rotates continuously under the drive of the drive unit, conveying the material forward along the screen surface. Hydraulic press II, through its drive toothed plate meshing with the transmission gears at the ends of each screening screen, causes the screens to undergo periodic deflection, resulting in periodic opening and closing of the roller gaps. The upper screening screen group has a larger roller gap, trapping large particles such as clods of earth, large stones, and long straw segments. These large impurities fall from the roller gaps into the dust removal platform below as the screens deflect. The middle screening screen group has a roller gap matching the normal grain size, allowing normal grains to remain on the middle screen and be conveyed forward with the rotation of the rollers. The lower screening screen group has the smallest roller gap, intercepting fine sand, gravel, and broken particles. Servo motor IV drives the upper and lower screening screen groups to rotate, while hydraulic press I drives the middle screening screen group. The rotation speed of the three screening screens can be independently adjusted to meet the screening needs of different materials. The dust removal platform operates continuously, automatically conveying impurities falling from the upper and lower screening screens to the outside of the equipment for discharge, eliminating the need for manual cleaning during machine shutdown. The periodic deflection motion of the screening screen ensures that particles smaller than the roller gap pass through smoothly, while the dynamic changes in the roller gap effectively prevent particles from getting stuck, completely solving the problem of easy clogging of traditional fixed screens.

[0022] After screening, the normal grains fall into the upper feeding area of ​​the annular separation column. A high-voltage electrostatic generator outputs a DC high voltage to the metal column of the annular separation column, creating a non-uniform electrostatic field near the column surface. When grain particles and impurity particles move through this electrostatic field region along the column surface, the magnitude of the dielectric polarization force experienced by the particles varies significantly due to the different relative permittivity of the different substances. According to the dielectric polarization force formula:

[0023] in, The vacuum permittivity, Where is the particle radius, Let be the relative permittivity of the particle. The electric field intensity gradient is given.

[0024] Particles with higher dielectric constants experience greater polarization forces, remain firmly adsorbed on the cylindrical surface for a longer period, rotate at a larger angle with the cylindrical surface, and fall further down. Particles with lower dielectric constants experience less polarization forces, are hardly adsorbed by the cylindrical surface, and detach from the cylindrical surface earlier under the influence of gravity. The subsequent cleaning rack scrapes off materials with different dielectric properties at different locations and guides them into different receiving chambers, achieving initial sorting.

[0025] Simultaneously, three servo motors drive one reciprocating screw to rotate via a worm gear set, causing the connecting table to move axially back and forth. During the movement of the cleaning wheel on the connecting table, the driven gear at its left end meshes with the driven gear plate fixed on the frame, causing the cleaning wheel to rotate. The cleaning wheel moves axially and rotates simultaneously, evenly conveying the intermediate material screened by the annular separation column to the frustum separation column for secondary selection.

[0026] The frustum-shaped separation column has a frustum-shaped structure. Material enters from the left end, which has a smaller diameter, and moves to the right along the column surface. As the column diameter gradually increases, the radius of curvature of the column surface gradually changes, resulting in a gradual change in the electric field distribution. The electric field intensity and gradient experienced by the material as it moves from left to right changes progressively, causing particles with different dielectric properties and sizes to detach from the column surface at different positions, achieving progressive and fine classification and sorting. The frustum-shaped column design effectively increases the sorting dimensions, achieving good separation even for particles with small differences in dielectric constant. The front cleaning rack scrapes and diverts the material on the frustum-shaped separation column according to their positions. The final high-quality normal grains are discharged from the main outlet, while various impurities are collected from their respective outlets. Through two-stage dielectric sorting with two columns connected in series, the sorting accuracy is significantly improved compared to a single-column structure.

[0027] This invention provides a sorting device and method for grain processing. It has the following beneficial effects: 1. This invention uses a servo motor inside the feeding platform to drive a reciprocating screw to make the feeding plate reciprocate linearly, so that the material falls evenly and intermittently through the bottom feeding gap, and in conjunction with the feeding pipe, the material is stably fed into the dust removal platform, thus achieving the feeding effect of uniform material dispersion, preventing agglomeration, and ensuring the consistency of subsequent sorting and feeding.

[0028] 2. This invention uses the combination of the fan inside the dust removal platform and the spiral shell to form an upward spiral flow field, which greatly extends the contact time between the grain and the airflow. In addition, the conical shell drives the auxiliary blades to rotate to enhance the stability of the flow field. The dust is collected by the negative pressure of the exhaust shell, which achieves the dust removal effect of efficient separation of light impurities and dust and avoids secondary re-entrainment.

[0029] 3. This invention achieves multi-level particle size classification screening through a three-layer deflectable screening screen group inside the screening table. The hydraulic press drives the screening screen to deflect periodically, causing the roller gap to change and prevent clogging. In conjunction with the dust removal table, it automatically and continuously discharges the intercepted impurities, achieving efficient classification screening, cleaning without stopping the machine, and continuous production screening effect.

[0030] 4. This invention forms a two-stage dielectric sorting structure by connecting the frustum-shaped separation column and the annular separation column in series in the sorting table. The frustum-shaped column provides a gradually changing electric field to achieve fine classification. In conjunction with the connecting table, the cleaning wheel rotates to push the material so that the material is evenly distributed, thus achieving high-quality fine sorting and significantly improving the sorting accuracy. Attached Figure Description

[0031] Figure 1 This is a perspective view of the present invention; Figure 2 This is a rear view of the present invention; Figure 3 This is a half-sectional view of the dust removal table of the present invention; Figure 4 This is a half-sectional view of the unloading platform of the present invention; Figure 5 This is a half-sectional view of the blanking plate of the present invention; Figure 6 This is a half-sectional view of the air separator of the present invention; Figure 7 This is a schematic diagram of the screening mesh structure of the present invention; Figure 8 This is a half-sectional view of the dust removal table of the present invention; Figure 9 This is a half-sectional view of the feed tube of the present invention; Figure 10 This is a schematic diagram of the exhaust shell structure of the present invention; Figure 11 This is a half-sectional view of the sorting table of the present invention; Figure 12 This is a schematic diagram of the frustum-shaped separation column structure of the present invention; Figure 13 This is a schematic diagram of the cleaning wheel structure of the present invention.

[0032] The components are as follows: 1. Sorting table; 2. Screening table; 3. Dust removal table; 4. Feeding table; 5. Servo motor one; 6. Servo motor two; 7. Servo motor three; 8. Servo motor four; 9. Fan; 10. Hydraulic press one; 11. Air separation chamber; 12. Servo motor five; 13. Support shell; 14. Hydraulic press two; 15. Screening shell; 16. Spiral shell; 17. Feeding plate; 18. Conical shell; 19. Feeding pipe; 20. Dust removal table; 21. Screening screen; 22. Exhaust shell; 23. Transmission rod; 24. Connecting plate; 25. Frustum separation column; 26. Annular separation column; 27. Reciprocating screw one; 28. Connecting table; 29. ​​Cleaning frame; 30. Cleaning wheel; 31. Reciprocating screw two. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0034] Example: like Figure 1-13 As shown, this embodiment of the invention provides a grain sorting device, including a sorting table 1, a screening table 2, a dust removal table 3, and a feeding table 4. The dust removal table 3 is positioned above the screening table 2, and the feeding table 4 is positioned above the dust removal table 3. A servo motor 5 is fixedly connected to the outer wall of the right end of the feeding table 4. A reciprocating screw 31 is fixedly connected to the drive end of the servo motor 5. A feeding plate 17 is connected to the outer wall of the reciprocating screw 31 via an adapter. The feeding plate 17 is slidably connected to the inner wall of the feeding table 4, and the bottom of the feeding plate 17 is flush with the inner wall of the feeding table 4. A material feeding gap is left between the inner bottom wall and the material feeding gap is 5mm to 15mm wide. A material feeding pipe 19 is provided at the bottom of the material feeding platform 4. The upper end of the material feeding pipe 19 is connected to the inner cavity of the material feeding platform 4, and the lower end of the material feeding pipe 19 extends into the interior of the spiral shell 16. The servo motor 5 is a stepper motor, which drives the reciprocating screw 31 to rotate through forward and reverse rotation, thereby driving the material feeding plate 17 to make reciprocating linear motion along the inner wall of the material feeding platform 4. The material feeding plate 17 completes one reciprocating motion to achieve one intermittent feeding, and the feeding frequency is 10 to 30 times per minute. The inner wall of the dust removal platform 3 is fixedly connected to the air separation chamber 11, the rear end of the dust removal platform 3 is fixedly connected to the fan 9, the inner wall of the air separation chamber 11 is fixedly connected to the spiral shell 16, the right outer wall of the air separation chamber 11 is provided with the exhaust shell 22, the top left side of the air separation chamber 11 is fixedly connected to the servo motor 12, the drive end of the servo motor 12 is fixedly connected to the worm gear, the central axis of the air separation chamber 11 is provided with the conical shell 18, the upper end of the conical shell 18 is fixedly connected to the worm wheel, the worm gear and the worm wheel mesh to form the worm gear assembly, the first output end of the fan 9 is connected to the lower part of the air separation chamber 11 through the air pipe, and the second output end is connected to the exhaust shell 22 through the air pipe. The spiral shell 16 descends in a spiral manner along the inner wall of the air separation chamber 11, the number of spiral turns is 3 to 5, and the spiral angle is 10° to 20°. A screening shell 15 is fixedly connected to the inner wall of the screening table 2. Several screening screens 21 are rotatably connected to the inner wall of the screening shell 15. A hydraulic press 14 is arranged on the left side of the screening shell 15. The screening screens 21 include an upper screening screen group, a middle screening screen group, and a lower screening screen group. Each screening screen group consists of multiple parallel rollers, and the spacing between the rollers decreases from top to bottom. A drive gear plate is fixedly connected to the drive end of the hydraulic press 14. A transmission gear is fixedly connected to the left end of each screening screen 21. The drive gear plate meshes with each transmission gear. A servo motor 8 is arranged on the front left side of the inner wall of the screening shell 15. A hydraulic press 10 is installed on the rear left side of the inner wall of the screening shell 15. A transmission rod 23 is fixedly connected to the drive end of the servo motor 4 8. A connecting plate 24 is fixedly connected to the drive end of the hydraulic press 10. The transmission rod 23 is connected to the upper and lower screening mesh groups through the worm gear group 2. The connecting plate 24 is connected to the middle screening mesh group through the worm gear group 2. A dust discharge platform 20 is fixedly connected to the rear side of the inner wall of the screening shell 15. The dust discharge platform 20 penetrates the rear wall of the screening shell 15 and extends to the outside of the screening platform 2. A support shell 13 is installed at the bottom of the inner wall of the screening platform 2. The screening shell 15 is fixedly installed on the top of the support shell 13. A frustum-shaped separating column 25 is rotatably connected to the front end of the inner wall of the sorting table 1, and an annular separating column 26 is rotatably connected to the rear end of the inner wall of the sorting table 1. High-voltage electrostatic generators are installed inside the frustum-shaped separating column 25 and the annular separating column 26. The frustum-shaped separating column 25 has a frustum-shaped structure with a diameter that gradually increases from the left end to the right end, and a taper of 5° to 10°. The annular separating column 26 has a cylindrical structure with a uniform diameter. A servo motor 26 is fixedly connected to the rear right side of the sorting table 1. An active conveyor wheel 1 is fixedly connected to the drive end of the servo motor 26. Driven conveyor wheels 1 are fixedly connected to the right ends of the frustum-shaped separating column 25 and the annular separating column 26, respectively. The active conveyor wheel 1 is connected to the two driven conveyor wheels 1 via a conveyor belt 1. The output voltage of the high-voltage electrostatic generator is 15kV to 30kV, and it is electrically connected to the metal columns of the frustum-shaped separating column 25 and the annular separating column 26, respectively, for sorting. A front cleaning frame and a rear cleaning frame are rotatably connected to the central axis on the left and right sides of the inner wall of the sorting platform 1, respectively. A servo motor 3 7 is fixedly connected to the front left side of the sorting platform 1. An active transmission wheel 2 is fixedly connected to the drive end of the servo motor 3 7. A driven transmission wheel 2 is fixedly connected to the left end of the front cleaning frame and the rear cleaning frame, respectively. The active transmission wheel 2 and the two driven transmission wheels 2 are connected by a transmission belt 2. A worm gear 3 is sleeved on the outer side of the drive end of the servo motor 3 7. A reciprocating screw 1 27 is rotatably connected to the left side of the inner wall of the sorting platform 1. A worm wheel 3 is fixedly connected to the left end of the reciprocating screw 1 27. The worm gear 3 and the worm wheel 3 mesh to form a worm gear and worm wheel assembly 3. A connecting platform 28 is sleeved on the outer wall of the reciprocating screw 1 27. A cleaning wheel 30 is rotatably connected to the inner wall of the connecting platform 28. A driven gear is fixedly connected to the left end of the cleaning wheel 30. A driven gear plate is fixedly connected to the left end of the inner wall of the sorting platform 1. The driven gear meshes with the driven gear plate.

[0035] It includes an intelligent control unit, which is electrically connected to servo motor 15, fan 9, servo motor 512, hydraulic press 214, servo motor 48, hydraulic press 10, servo motor 26, servo motor 37 and high-voltage electrostatic generator respectively. The intelligent control unit has a built-in preset parameter library for various grain varieties. By receiving the detection signals from each sensor, it automatically adjusts the operating parameters of each drive component to achieve fully automated sorting control.

[0036] Specifically, the overall layout adopts a vertical stacked design, with four feeding platforms, three dust removal platforms, two screening platforms, and one sorting platform arranged sequentially from top to bottom. These four functional units are connected by flange bolts to form a continuous four-stage sorting production line. The machine is approximately 2.8 meters high, occupies an area of ​​approximately 1.5 square meters, and has a processing capacity of 2t / h to 5t / h.

[0037] The unloading platform 4 is located at the top of the entire machine and adopts a rectangular box structure with external dimensions of 800mm (length) × 600mm (width) × 500mm (height). The box body is welded from 3mm thick 304 stainless steel plate, and the inner wall is polished to reduce material flow resistance. The top of the unloading platform 4 has a feed inlet, and the bottom has a discharge pipe 19 that connects to the dust collection platform 3 below. A servo motor 5 is bolted to the outer wall of the right end of the unloading platform 4. The servo motor 5 is a 57 series stepper servo motor with a step angle of 1.8°, and is equipped with a servo driver to achieve precise position and speed control. The output shaft of the servo motor 5 is fixedly connected to a reciprocating lead screw 31 via a coupling. The reciprocating lead screw 31 horizontally penetrates the right end wall of the unloading platform 4 and extends into the box body. The lead screw has a diameter of 20mm, a lead of 5mm, and an effective stroke of 400mm. The outer wall of the reciprocating lead screw 31 is connected to a feed plate 17 via a ball nut adapter. The feed plate 17 is a vertically arranged rectangular plate with a height of 350mm and a width the same as the inner cavity width of the box. The left and right sides of the feed plate 17 are slidably connected to the inner wall of the feed platform 4 via a guide rail slider structure. The guide rails are linear guide rails to ensure the smooth movement of the feed plate. A 10mm wide feed gap is left between the bottom of the feed plate 17 and the inner bottom wall of the feed platform 4. The width of this gap can be adjusted by adjusting the installation height of the feed plate, with an adjustment range of 5mm to 15mm, to accommodate grains of different sizes.

[0038] During operation, servo motor 5 drives reciprocating screw 31 to rotate via forward and reverse rotation. The ball bearing nut converts the rotational motion into linear motion, causing the feeding plate 17 to reciprocate linearly along the inner wall of the feeding platform 4. When the feeding plate moves forward, it pushes the material forward, and the material falls evenly through the feeding gap at the bottom of the feeding plate, entering the dust collection platform 3 below via the feeding pipe 19. When the feeding plate moves backward, the material behind replenishes the position in front. Each reciprocating motion of the feeding plate achieves one intermittent feeding. The feeding frequency can be controlled by adjusting the motor speed and reciprocating stroke. In this embodiment, the feeding frequency is set to 20 times per minute. This intermittent feeding method effectively avoids material clumping, ensures the uniformity of feeding to subsequent sorting units, and controls the material layer thickness fluctuation within ±10%.

[0039] The dust collection table 3 is located below the unloading table 4. It is a cylindrical vertical structure with an outer diameter of 600mm and a height of 1000mm, constructed from 3mm thick 304 stainless steel plate. An air separator 11, a cylindrical shell with an inner diameter of 500mm, is fixedly connected to the inner wall of the dust collection table 3, forming an annular sandwich air duct with the dust collection table 3. A fan 9, a high-pressure centrifugal fan with a power of 2.2kW and a total air volume of 1500m³, is bolted to the rear end of the dust collection table 3. 3The air volume is 3000Pa / h, with a wind pressure of 3000Pa. It has three independent output ports, and the air volume of each port can be independently controlled by the built-in regulating damper.

[0040] A spiral shell 16 is fixedly connected to the inner wall of the air separation chamber 11. The spiral shell 16 descends spirally along the inner wall of the air separation chamber 11, with a total of 4 spirals and a spiral angle of 15°. The guide plate is 80mm wide, 3mm thick, and polished. The upper end of the spiral shell 16 is aligned with the lower end of the feed pipe 19, and the lower end is aligned with the feed inlet of the screening table 2. Grains enter from the top and slide down the spiral shell in a spiral trajectory. A servo motor 12 is fixedly connected to the top left of the air separation chamber 11 via a motor mount. The servo motor 12 is a three-phase asynchronous servo motor with a power of 0.75kW and a speed of 1400r / min. The output shaft of the servo motor 12 is fixedly connected to a worm gear 1 via a key. A conical shell 18 is set on the central axis of the air separation chamber 11. The conical shell 18 is an inverted conical shell structure with an upper diameter of 100mm, a lower diameter of 200mm, and a height of 800mm. The upper and lower ends are supported by bearing seats. A worm gear is fixed to the upper end of the conical shell 18 via a key connection. The worm and the worm gear mesh to form a worm gear assembly with a reduction ratio of 30:1. Helical auxiliary blades are fixed on the outer wall of the conical shell 18. The blades are 30 mm wide and have a pitch of 200 mm.

[0041] The first output end of the fan 9 is connected to the lower side wall of the air separator 11 through a duct. The air inlet is set tangentially so that the airflow enters along the tangential direction of the cylinder wall to form a vortex. The second output end is connected to the exhaust shell 22 at the top of the air separator 11 through a duct. The exhaust shell 22 is set on the outer wall of the right end of the air separator 11. The pipe diameter is 100mm and the end is connected to a bag filter. The third output end is a spare port that can be connected to other auxiliary air paths as needed.

[0042] During operation, grains fall from the feed pipe 19 into the upper part of the air separator 11 and slide down the spiral shell 16 in a spiral trajectory. The first output end of the blower 9 sends a high-speed airflow into the lower part of the air separator. Guided by the spiral shell, the airflow forms an upward spiral flow field with a wind speed of approximately 12 m / s. The grains make full contact with the upward airflow during their descent, with the contact time being approximately three times longer than that of traditional vertical air separators. Light impurities and dust gather towards the center of the cylinder under the lift of the airflow and move upwards, eventually being extracted and collected by the negative pressure airflow at the second output end through the top exhaust shell 22. The servo motor 12 drives the conical shell 18 to rotate at a speed of 50 r / min via a worm gear assembly. The spiral auxiliary blades on the outer wall of the conical shell further enhance the stability of the spiral flow field, prevent airflow turbulence, and improve dust separation efficiency. In this embodiment, the dust removal rate can reach over 92%.

[0043] The screening table 2 is located below the dust removal table 3. It has a rectangular box structure with dimensions of 1200mm (length) × 800mm (width) × 600mm (height) and is constructed from 3mm thick steel plate. A support shell 13, 100mm high, is located at the bottom of the inner wall of the screening table 2. This support shell supports the screening shell 15 above it and provides stable support. The screening shell 15 is bolted to the top of the support shell 13. The screening shell 15 is made of stainless steel plate and contains three layers of screening mesh: an upper, middle, and lower layer. Each screening mesh group consists of eight parallel screening meshes 21 with a diameter of 30mm. The roller surface has annular raised stripes to increase friction. The roller spacing of each screening mesh group is different. The roller spacing of the upper screening mesh group is 12mm, which is used to intercept large particles of impurities such as soil clods, stones, and straw pieces; the roller spacing of the middle screening mesh group is 5mm, which is used to retain normal grains; and the roller spacing of the lower screening mesh group is 2mm, which is used to intercept fine sand and gravel.

[0044] A hydraulic press 14 is located on the left side of the screening shell 15. The hydraulic press 14 employs an electro-hydraulic push rod driven by a toothed plate. The push rod has a stroke of 100mm and a thrust of 5000N. A drive toothed plate is fixedly connected to the end of the extension rod of the hydraulic push rod. The drive toothed plate is vertically positioned, 300mm long, and has a module of 2mm. Each screening mesh 21 has a transmission gear fixedly connected to its left end via a key. The transmission gear has a module of 2mm and 30 teeth. The drive toothed plate meshes simultaneously with each transmission gear. When the hydraulic push rod drives the drive toothed plate up and down, each transmission gear rotates synchronously, thereby causing each screening mesh to deflect. The deflection angle range is 0° to 30°.

[0045] A servo motor 4 (8) is fixedly connected to the front left side of the inner wall of the screening shell 15 via a motor mount, and a hydraulic press 10 is fixedly connected to the rear left side of the inner wall via a support. The servo motor 4 (8) is a gear-reduced servo motor with a power of 0.37kW and an output speed of 100r / min. The output shaft of the servo motor 4 (8) is fixedly connected to a transmission rod 23 via a coupling, and a connecting plate 24 is fixedly connected to the drive end of the hydraulic press 10. The transmission rod 23 is connected to the rollers of the upper and lower screening mesh groups via a worm gear set 2, and the connecting plate 24 is connected to the rollers of the middle screening mesh group via a worm gear set 2. The outer wall of the transmission rod is slidably connected to the worm gear 2 via a spline, allowing the worm gear 2 to slide axially when the screening mesh deflects, ensuring the continuity of transmission.

[0046] A dust discharge platform 20 is fixedly connected to the rear inner wall of the screening shell 15. The dust discharge platform is a horizontally arranged screw conveyor with a diameter of 80mm, a screw pitch of 60mm, and a length equal to the width of the screening shell. The left end of the dust discharge platform 20 is supported by a bearing seat, and the right end penetrates the rear wall of the screening shell 15 and extends to the outside of the screening table 2, driven by an independent geared motor. The discharge end of the dust discharge platform is inclined downward at 45° to facilitate the discharge of impurities.

[0047] During operation, the dust-removed grains enter from the top of the screening shell 15 and first fall onto the upper screening screen group. Servo motor 48 drives the upper and lower screening screen groups to rotate at 80 r / min, while hydraulic press 10 drives the middle screening screen group to rotate at 45 r / min via connecting plate 24. The rotation of the screening screens propels the material forward, while hydraulic press 24 drives each screening screen to periodically deflect via a drive toothed plate, with the deflection angle varying between 0° and 20°. This deflection causes periodic changes in the roller gap, effectively screening particles of different sizes while preventing particles from getting stuck in the roller gap and causing blockages. Large particles of impurities trapped by the upper screening screen group and fine sand and gravel intercepted by the lower screening screen group fall into the dust discharge platform 20 below as the screens deflect, and the dust discharge platform transports the impurities to the outside of the screening table 2 for discharge. Normal grains on the middle screening screen group fall from the discharge end of the middle screening screen into the sorting table 1 below.

[0048] The sorting table 1 is located below the screening table 2. It has a rectangular box-like structure with dimensions of 1200mm (length) × 800mm (width) × 500mm (height), and is constructed of welded steel plates with an inner wall lined with an insulating board. A frustum-shaped separating column 25 is rotatably connected to the front end of the inner wall of the sorting table 1, and an annular separating column 26 is rotatably connected to the rear end. The two separating columns are arranged horizontally and parallel to each other, with a spacing of 200mm. The frustum-shaped separating column 25 has a frustum-shaped structure with a diameter of 150mm at the left end, a diameter of 250mm at the right end, a taper of 8°, and a length of 600mm. The annular separating column 26 has a cylindrical structure with a diameter of 200mm and a length of 600mm. Both separating columns consist of an internal metal column and a surface-covered insulating dielectric layer. The metal column is made of stainless steel, and the insulating dielectric layer is made of polytetrafluoroethylene (PTFE) with a thickness of 1mm.

[0049] Servo motor 2 (6) is fixedly connected to the rear right side of sorting station 1 via a motor mount. Servo motor 2 (6) is a gear-reduced servo motor with a power of 0.75kW and an output speed of 60r / min. The output shaft of servo motor 2 (6) is fixedly connected to a drive conveyor wheel 1 via a key. The right ends of the frustum-shaped separation column 25 and the right ends of the annular separation column 26 are respectively fixedly connected to driven conveyor wheels 1 via keys. The drive conveyor wheel 1 and the two driven conveyor wheels 1 are connected by a conveyor belt 1 to achieve synchronous and co-directional rotation of the two separation columns.

[0050] The high-voltage electrostatic generator is located in the side control box of sorting station 1. It is a DC high-voltage generator with a continuously adjustable output voltage of 15kV to 30kV and an output current of 0.5mA. It has overcurrent protection and short-circuit protection functions. The high-voltage output terminal of the high-voltage electrostatic generator is electrically connected to the metal columns of the frustum-shaped separation column 25 and the annular separation column 26 via high-voltage cables, so that the column surfaces are charged with high-voltage static electricity.

[0051] The sorting table 1 has a front cleaning frame 29 and a rear cleaning frame rotatably connected to its central axis on both sides of the inner wall. The cleaning frames are made of polyurethane material, which has good wear resistance and elasticity. The front cleaning frame is located directly below the frustum-shaped separation column, and the rear cleaning frame is located directly below the annular separation column. The cutting edge of the cleaning frame maintains appropriate contact pressure with the column surface. A servo motor 37 is fixedly connected to the left front end of the sorting table 1 via a motor mount. The servo motor 37 is a three-phase asynchronous servo motor with a power of 0.25kW and a speed of 90r / min. The output shaft of the servo motor 37 is fixedly connected to the active transmission wheel 2 via a key. The left ends of the front and rear cleaning frames are fixedly connected to the driven transmission wheels 2 via keys. The active transmission wheel 2 and the two driven transmission wheels 2 are connected by a conveyor belt 2 to achieve synchronous rotation of the two cleaning frames.

[0052] The output shaft of servo motor 37 is also connected and fixed to worm gear 3 via a key. A reciprocating screw 27 is rotatably connected to the left side of the inner wall of sorting table 1 via a bearing seat. Reciprocating screw 27 is horizontally positioned, with a diameter of 20mm, a lead of 5mm, and a length of 500mm. A worm gear 3 is fixed to the left end of reciprocating screw 27 via a key. Worm gear 3 and worm gear 3 mesh to form a worm gear assembly 3 with a reduction ratio of 20:1. A connecting platform 28 is fitted onto the outer wall of reciprocating screw 27 via a ball nut. Connecting platform 28 has a portal-shaped structure and spans above the annular separation column 26. A cleaning wheel 30 is rotatably connected to the inner wall of connecting platform 28 via bearings. The cleaning wheel has a diameter of 30mm and flexible material-feeding teeth on its surface. The left end of the cleaning wheel 30 is fixed with a driven gear by a key connection, and the left end of the inner wall of the sorting table 1 is fixed with a driven toothed plate by a bracket. The driven toothed plate is set horizontally and its length is the same as the travel of the connecting table. The driven gear meshes with the driven toothed plate.

[0053] During operation, the screened normal grains fall from the screening table 2 into the upper part of the annular separation column 26. A high-voltage electrostatic generator applies a 25kV high-voltage static charge to the surface of the annular separation column, creating a non-uniform electrostatic field near the column surface. When grain particles and impurity particles pass through the electrostatic field region, the dielectric polarization forces experienced by the particles differ due to the varying dielectric constants of the different materials. Particles with a higher dielectric constant experience a greater polarization force, remain adsorbed on the column surface for a longer period, rotate at a larger angle with the column surface, and fall further down the column; conversely, particles with a lower dielectric constant experience a smaller polarization force and detach from the column surface earlier. A subsequent cleaning rack scrapes off materials with different dielectric properties at different locations and distributes them to different receiving chambers.

[0054] Servo motor 37 simultaneously drives reciprocating screw 27 to rotate via worm gear set 3. The ball nut converts the rotational motion into linear motion, causing connecting table 28 to reciprocate along the axis of the reciprocating screw. During the movement of the cleaning wheel 30 on the connecting table, the driven gear at its left end meshes with the fixed driven gear plate, causing the cleaning wheel to rotate. The cleaning wheel moves axially while rotating, evenly conveying the intermediate material screened by the annular separation column 26 to the frustum separation column 25 for secondary sorting.

[0055] The frustum-shaped separation column 25 has a frustum-shaped structure. Material enters from the left end, where the diameter is smaller, and moves to the right along the column surface. As the column diameter gradually increases, the linear velocity and electric field distribution on the column surface also gradually change, achieving progressive grading and sorting. The frustum-shaped column design ensures that particles of different sizes and dielectric properties experience electric field intensities on the column surface, resulting in finer sorting. The frustum-shaped separation column operates at 20kV, slightly lower than that of the annular separation column, and is mainly used for secondary refining of intermediate materials to further improve sorting accuracy. The front cleaning frame scrapes and diverts the material from the frustum-shaped separation column. The final normal grains are discharged from the main outlet, while various impurities are collected from their respective outlets.

[0056] The intelligent control unit is located in the electrical control cabinet on the side of the machine. It uses a PLC programmable controller as the core controller and is equipped with a 7-inch touchscreen human-machine interface. The intelligent control unit is electrically connected to servo motor 5, fan 9, servo motor 12, hydraulic press 14, servo motor 8, hydraulic press 10, servo motor 6, servo motor 7, and the high-voltage electrostatic generator. The intelligent control unit has a built-in preset parameter library for various grain varieties such as wheat, rice, corn, and soybeans. Users only need to select the grain variety on the touchscreen, and the system will automatically call up the corresponding complete set of operating parameters, including feeding frequency, fan air volume, screen rotation speed, deflection angle, sorting voltage, and column speed, achieving one-click switching. Simultaneously, the intelligent control unit also has functions such as fault self-diagnosis, operating status monitoring, and output statistics, greatly reducing the requirements for operators.

[0057] A grain sorting method for grain processing includes the following steps: Step S1, Intermittent feeding: The grains to be sorted are fed into the feeding table 4. The servo motor 5 drives the feeding plate 17 to reciprocate, so that the grains fall evenly and intermittently into the feeding pipe 19 through the feeding gap at the bottom of the feeding plate 17, and then enter the dust removal table 3. Step S2, Spiral Dust Removal: After the grain enters the air separation chamber 11, it slides down the spiral shell 16 in a spiral trajectory. The fan 9 introduces high-speed airflow into the air separation chamber 11 to form a spiral air field, which separates the dust and light impurities in the grain and discharges them through the exhaust shell 22. The airflow velocity sent to the lower part of the air separation chamber 11 by the first output end of the fan 9 is 8m / s to 15m / s. The airflow forms an upward spiral flow field along the spiral shell 16. The servo motor 12 drives the conical shell 18 to rotate through the worm gear assembly 1 at a speed of 30r / min to 60r / min. The conical shell 18 drives the auxiliary blades to rotate to enhance the stability of the spiral flow field. The second output end of the fan 9 generates negative pressure to extract the separated dust through the exhaust shell 22. Step S3, Roller Screening: After dust removal, the grain falls into the screening shell 15. The three-layer screening mesh group classifies and screens the grain. The upper screening mesh group intercepts large particles of impurities, the middle screening mesh group retains normal grains, and the lower screening mesh group intercepts fine sand and gravel. The hydraulic press 2 14 drives the screening mesh to deflect, causing impurities to fall into the dust discharge platform 20 for discharge. The hydraulic press 2 14 drives the transmission gears of each screening mesh 21 to rotate through the drive tooth plate, causing the screening mesh to deflect. The deflection angle range is 0° to 30°. The servo motor 4 8 drives the upper and lower screening mesh groups to rotate through the worm gear group 2 at a speed of 50 r / min to 100 r / min. The hydraulic press 10 drives the middle screening mesh group to rotate through the worm gear group 2 at a speed of 30 r / min to 60 r / min. The large particles of impurities intercepted by the upper screening mesh group and the fine sand and gravel intercepted by the lower screening mesh group fall into the dust discharge platform 20 and are transported by the dust discharge platform 20 to the outside of the screening table 2 for discharge. Step S4, Dielectric Sorting: The normal grains after screening fall into the sorting table 1. The high-voltage electrostatic generator creates a high-voltage electrostatic field on the surface of the frustum separation column 25 and the annular separation column 26. Particles with different dielectric properties are subjected to different polarization forces, resulting in different motion trajectories. The material is diverted to different channels by the front cleaning frame and the rear cleaning frame to complete the fine selection. The frustum separation column 25 has a frustum-shaped structure. The material enters from the left end with a smaller diameter. As it moves to the right along the column surface, the electric field strength gradually changes, realizing progressive grading and sorting. The annular separation column 26 has a cylindrical structure and performs secondary fine selection on the normal grains output from the frustum separation column 25. The servo motor 37 drives the reciprocating screw 1 27 to rotate through the worm gear group 3, which drives the connecting table 28 to move axially. The cleaning wheel 30 on the connecting table 28 rotates under the meshing action of the driven gear and the driven tooth plate, and evenly sends the material screened by the annular separation column 26 to the frustum separation column 25.

[0058] Example 1 Step S1: Intermittent feeding. Grains to be sorted, taking wheat as an example with a moisture content of approximately 13%, are poured into the feed inlet of the feeding platform 4. Under gravity, the grains accumulate in front of the feeding plate 17. The servo motor 5 drives the reciprocating screw 31 to rotate forward and backward according to a preset frequency and stroke, causing the feeding plate 17 to reciprocate linearly along the inner wall of the feeding platform 4. When the feeding plate moves forward, it pushes the grains in front forward, and the grains fall evenly through the 10mm wide feeding gap at the bottom of the feeding plate, entering the dust collection platform 3 below via the feeding pipe 19. When the feeding plate moves backward, the grains behind replenish the front position under gravity. In this embodiment, the reciprocating stroke of the feeding plate is 300mm, the reciprocating frequency is 20 times per minute, and the feeding rate is stable at approximately 3t / h. This intermittent feeding method effectively breaks up material clumps, allowing the grains to enter the subsequent sorting unit in a uniform thin layer. The material layer thickness is controlled at around 20mm, with a fluctuation range of no more than ±2mm, creating favorable feeding conditions for subsequent dust removal and screening.

[0059] Step S2: Spiral Dust Removal. Grains fed through intermittent feeding enter the upper end of the air separation chamber 11 through the feeding pipe 19 and slide down the spiral shell 16 in a spiral trajectory. The first output end of the blower 9 sends a high-speed airflow into the lower part of the air separation chamber. After entering through the tangential air inlet, the airflow forms a stable upward spiral flow field under the guidance of the spiral shell, with an airflow velocity of approximately 12 m / s. The grains remain in continuous contact with the upward airflow during their spiral descent, with the contact time being approximately three times longer than that of traditional vertical air separation, ensuring thorough separation of light impurities and dust.

[0060] Servo motor 512 drives conical shell 18 to rotate at a speed of 50 r / min after being reduced by worm gear set 1. The spiral auxiliary blades on the outer wall of the conical shell rotate synchronously, further enhancing the stability of the spiral flow field, preventing turbulence and short-circuiting of the airflow, and making the airflow distribution in the entire cylinder more uniform. Light impurities such as chaff, wheat awns, dust, and shriveled particles gather towards the center of the cylinder under the lift of the airflow and move towards the top with the rising airflow. The second output end of fan 9 creates a negative pressure at exhaust shell 22, which draws out the dust and light impurities gathered at the top and sends them to the external bag filter for collection and treatment.

[0061] This step can remove more than 92% of dust and light impurities from grains. At the same time, due to the uniformity of the spiral flow field, the loss rate of normal grains is controlled below 0.3%, which is far lower than the loss rate of more than 1% of traditional air separation equipment.

[0062] Step S3: Roller Screening. After dust removal, the grain falls from the bottom of the dust removal platform into the screening shell 15 of the screening table 2, first reaching the upper screening mesh group. Servo motor 48 drives the upper and lower screening mesh groups to rotate at 80 r / min via worm gear set 2. Hydraulic press 10 drives the middle screening mesh group to rotate at 45 r / min via connecting plate 24. The rotation of the screening mesh causes the material to move forward along the screen surface. Simultaneously, hydraulic press 14 drives the drive toothed plate to reciprocate up and down via an electric hydraulic push rod. The drive toothed plate, through transmission gears, causes each screening mesh to generate a periodic deflection motion, with the deflection angle varying between 0° and 20°, and the deflection frequency being 30 times per minute.

[0063] The deflection motion of the screening mesh causes periodic opening and closing of the roller gaps, allowing particles smaller than the gaps to pass through smoothly while preventing particle jamming, effectively solving the clogging problem of traditional screens. The upper screening mesh group has a roller gap of 12mm, trapping large particles such as clogging clogging, large stones, and long straw segments. These large impurities fall from the roller gaps into the lower dust collection platform 20 as the screening mesh deflects. The middle screening mesh group has a roller gap of 5mm, allowing normal wheat grains to remain on the middle mesh and be conveyed forward, while smaller particles and fine sand fall through the roller gaps to the lower screening mesh group. The lower screening mesh group has a roller gap of 2mm, intercepting fine sand and particles, which are also discharged through the dust collection platform.

[0064] The dust removal table 20 operates continuously at 60 r / min, conveying impurities falling from the upper and lower screening screens to the outside of the screening table 2 for discharge. This eliminates the need for manual cleaning and achieves continuous impurity removal. Normal grains on the middle screening screen fall from its outlet into the lower sorting table 1, entering the fine selection process. After this screening step, the removal rate of large and fine impurities in the grains can reach over 95%.

[0065] Step S4: Dielectric sorting. Normal grains, after screening, fall from the outlet of the middle screening mesh into the upper feeding area of ​​the annular separation column 26. Servo motor 26 drives the annular separation column to rotate clockwise at 40 r / min via conveyor belt 1. A high-voltage electrostatic generator outputs a 25kV DC high voltage, causing the metal column of the annular separation column to acquire a high-voltage electrostatic charge, forming an electric field with a strength of approximately 2×10⁻⁶ near the column surface. 6 A non-uniform electrostatic field with a voltage of V / m.

[0066] When wheat grains and various impurity particles move along the column surface through the electrostatic field region, the dielectric polarization forces experienced by the particles differ due to the varying relative permittivity of the different substances. Normal wheat, with a relative permittivity of approximately 3-5, experiences moderate polarization forces and, after adsorbing on the column surface for a certain period, detaches under gravity and falls from the lower middle position of the annular separation column. Impurities with high dielectric constants, such as metal fragments and certain minerals, experience stronger polarization forces and are firmly adsorbed onto the column surface, falling from a more distant position as the column rotates through a larger angle. Impurities with low dielectric constants, such as plastic flakes and certain organic impurities, experience weaker polarization forces and are hardly adsorbed by the column surface, falling directly from the front of the column under gravity. The rear cleaning rack scrapes off the materials falling from different positions and guides them into three receiving chambers, achieving preliminary sorting.

[0067] Servo motor 37 simultaneously drives reciprocating screw 27 to rotate after reduction via worm gear set 3, causing connecting table 28 to reciprocate axially at a speed of 50 mm / s and a stroke of 400 mm. During the movement of the cleaning wheel 30 on the connecting table, the driven gear at its left end meshes with the driven gear plate fixed on the frame, causing the cleaning wheel to rotate at a speed of approximately 60 r / min. The cleaning wheel moves axially while rotating, evenly conveying the intermediate material (the incompletely separated portion) under the screen of the annular separation column to the frustum separation column 25 for secondary refining.

[0068] The frustum-shaped separation column 25 has a frustum-shaped structure, with material entering from the left end where the diameter is smaller. A high-voltage electrostatic generator outputs a 20kV DC high voltage to the frustum-shaped separation column. Due to the frustum shape, the column diameter gradually increases from left to right, and the radius of curvature of the column surface gradually changes, resulting in a gradual change in the electric field distribution. As the material moves from the left end to the right end, the electric field intensity and gradient it experiences gradually change, causing particles with different dielectric properties and particle sizes to detach from the column surface at different positions, achieving progressive fine sorting. The frustum-shaped column design effectively increases the sorting dimensions, achieving good separation results even for particles with small differences in dielectric constant. The front cleaning rack scrapes and diverts the material on the frustum-shaped separation column according to its position. The final high-quality normal grains are discharged from the main outlet, while various impurities are collected from their respective outlets.

[0069] Through the above four-stage sorting process, the present invention can achieve fine sorting of grains, with a comprehensive impurity removal rate of over 99% and a finished grain purity of over 99.5%, which is far higher than the level of traditional sorting equipment.

[0070] Example 3 The difference between this embodiment and Embodiment 2 is that this embodiment optimizes the parameters for rice sorting.

[0071] In step S1, during the intermittent feeding process, due to the small size of the rice grains and the high content of husks, the width of the feeding gap at the bottom of the feeding plate is adjusted to 8mm, and the reciprocating frequency of the feeding plate is adjusted to 25 times per minute to accommodate the small size of the rice grains and ensure more uniform feeding. The feeding rate is adjusted to 2.5t / h.

[0072] In step S2, the spiral dust collector, due to the density of rice particles being approximately 1150 kg / m³, 3 Slightly smaller than wheat, and with a higher content of light impurities such as husks, the air velocity at the first output end of the fan is appropriately reduced to 10 m / s to minimize losses of normal rice that are carried away by the airflow. The speed of servo motor five is adjusted to 60 r / min to enhance the stability of the spiral flow field and improve the separation effect of light impurities. The negative pressure air volume at the second output end of the fan is appropriately increased to accommodate the higher content of light impurities. The dust and light impurity removal rate in this step can reach over 90%.

[0073] In step S3, the roller spacing of the three-layer screening mesh group is adjusted accordingly: the upper screening mesh group's roller spacing is adjusted to 10mm, the middle screening mesh group's roller spacing is adjusted to 3.5mm, and the lower screening mesh group's roller spacing is adjusted to 1.5mm, to adapt to the small size of rice grains. The screening mesh deflection angle is adjusted to 0°~25°, and the deflection frequency is adjusted to 35 times per minute to enhance the screening effect and anti-clogging ability. The rotation speed of the upper and lower screening mesh driven by the servo motor is adjusted to 90r / min, and the rotation speed of the middle screening mesh driven by the hydraulic press is adjusted to 50r / min. The dust removal table rotation speed is adjusted to 70r / min.

[0074] In step S4, dielectric separation, the output voltage of the high-voltage electrostatic generator is adjusted accordingly: the voltage of the annular separation column is adjusted to 22kV, and the voltage of the frustum separation column is adjusted to 18kV. The rotation speed of the separation columns is adjusted to: 50r / min for the annular separation column and 70r / min for the frustum separation column. Due to the small size of rice grains, the taper of the frustum separation column is adjusted to 6° to obtain a finer, gradual separation effect. The moving speed of the connecting platform is adjusted to 60mm / s, and the rotation speed of the washing wheel is adjusted to 70r / min.

[0075] The remaining steps and device structure are the same as in Embodiment 2, and will not be repeated here.

[0076] Example 4 The difference between this embodiment and Embodiment 2 is that this embodiment optimizes the parameters for corn sorting.

[0077] In step S1, during the intermittent feeding process, due to the large size of the corn kernels, the width of the feeding gap at the bottom of the feeding plate is adjusted to 15mm, and the reciprocating frequency of the feeding plate is adjusted to 15 times per minute to accommodate the larger corn kernels. The feeding rate is adjusted to 4t / h.

[0078] In step S2, the spiral dust collector... (The sentence is incomplete and requires more context to translate accurately.) 3 The air velocity at the first output end of the blower is increased to 14 m / s to ensure sufficient airflow lift for separating light impurities. The speed of servo motor five is adjusted to 40 r / min. Since the content of light impurities in corn is relatively low, the negative pressure airflow at the second output end of the blower is appropriately reduced. This step achieves a dust and light impurity removal rate of over 93%.

[0079] In step S3, the roller spacing of the three-layer screening mesh group is adjusted accordingly: the upper screening mesh group's roller spacing is adjusted to 15mm, the middle screening mesh group's roller spacing is adjusted to 7mm, and the lower screening mesh group's roller spacing is adjusted to 3mm, to accommodate the larger size of corn kernels. The screening mesh deflection angle is adjusted to 0°~25°, and the deflection frequency is adjusted to 25 times per minute. The rotation speed of the upper and lower screening mesh groups driven by four servo motors is adjusted to 60r / min, and the rotation speed of the middle screening mesh group driven by one hydraulic press is adjusted to 35r / min, to meet the screening requirements of larger particles.

[0080] In step S4, dielectric separation, the output voltage of the high-voltage electrostatic generator is increased accordingly: the voltage of the annular separation column is adjusted to 28kV, and the voltage of the frustum separation column is adjusted to 24kV. Because corn kernels are relatively large and have relatively strong polarization forces, appropriately increasing the voltage can enhance the ability to identify and separate moldy kernels whose dielectric constant differs significantly from that of normal corn. The rotation speed of the separation columns is adjusted to: 30 r / min for the annular separation column and 45 r / min for the frustum separation column. The taper of the frustum separation column is adjusted to 10° to accommodate the gradual separation requirements of larger particles. The moving speed of the connecting platform is adjusted to 40 mm / s, and the rotation speed of the washing wheel is adjusted to 50 r / min.

[0081] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A grain processing sorting device, comprising a sorting table (1), a screening table (2), a dust removal table (3), and a feeding table (4), characterized in that: The dust removal table (3) is located above the screening table (2), and the unloading table (4) is located above the dust removal table (3); A servo motor (5) is fixedly connected to the outer wall of the right end of the unloading platform (4). A reciprocating screw (31) is fixedly connected to the drive end of the servo motor (5). A unloading plate (17) is connected to the outer wall of the reciprocating screw (31) through an adapter. The unloading plate (17) is slidably connected to the inner wall of the unloading platform (4). The dust removal platform (3) is fixedly connected to the inner wall of the air separation chamber (11), the dust removal platform (3) is fixedly connected to the rear end of the fan (9), the air separation chamber (11) is fixedly connected to the inner wall of the air separation chamber (11), and the air separation chamber (11) is provided with an exhaust shell (22) on the right outer wall. The inner wall of the screening platform (2) is fixedly connected to a screening shell (15), and the inner wall of the screening shell (15) is rotatably connected to a number of screening screens (21). A hydraulic press (14) is provided on the left side of the screening shell (15). The inner front end of the sorting table (1) is rotatably connected to a frustum separation column (25), and the rear end of the inner wall of the sorting table (1) is rotatably connected to an annular separation column (26). A high-voltage electrostatic generator is provided on the inner side of the frustum separation column (25) and the annular separation column (26).

2. The grain sorting device according to claim 1, characterized in that: A material feeding gap is left between the bottom of the feeding plate (17) and the inner bottom wall of the feeding platform (4), and the width of the material feeding gap is 5mm to 15mm. The bottom of the feeding platform (4) is provided with a feeding pipe (19), the upper end of the feeding pipe (19) is connected to the inner cavity of the feeding platform (4), and the lower end of the feeding pipe (19) extends into the interior of the spiral shell (16). The servo motor (5) is a stepper motor. It drives the reciprocating screw (31) to rotate by forward and reverse rotation, which drives the feeding plate (17) to make reciprocating linear motion along the inner wall of the feeding table (4). The feeding plate (17) completes one reciprocating motion to realize one intermittent feeding. The feeding frequency is 10 to 30 times per minute.

3. The grain sorting device according to claim 1, characterized in that: A servo motor (12) is fixedly connected to the top left side of the air separation chamber (11). A worm gear is fixedly connected to the drive end of the servo motor (12). A conical shell (18) is provided on the central axis of the air separation chamber (11). A worm wheel is fixedly connected to the upper end of the conical shell (18). The worm gear and the worm wheel mesh to form a worm wheel and worm gear assembly. The first output end of the blower (9) is connected to the lower part of the air separator (11) through a duct, and the second output end is connected to the exhaust shell (22) through a duct. The spiral shell (16) descends in a spiral manner along the inner wall of the air separation chamber (11), with 3 to 5 spiral turns and a spiral angle of 10° to 20°.

4. A grain sorting device according to claim 1, characterized in that: The screening mesh (21) includes an upper screening mesh group, a middle screening mesh group and a lower screening mesh group. Each screening mesh group consists of multiple parallel rollers, and the distance between each roller decreases from top to bottom. The drive end of the hydraulic press (14) is fixedly connected to a drive tooth plate, and the left end of each screen (21) is fixedly connected to a transmission gear. The drive tooth plate meshes with each transmission gear. A servo motor four (8) is provided on the front left side of the inner wall of the screening shell (15), and a hydraulic press one (10) is provided on the rear left side of the inner wall of the screening shell (15). A transmission rod (23) is fixedly connected to the drive end of the servo motor four (8), and a connecting plate (24) is fixedly connected to the drive end of the hydraulic press one (10). The transmission rod (23) is connected to the upper screening mesh group and the lower screening mesh group through a worm gear set two, and the connecting plate (24) is connected to the middle screening mesh group through a worm gear set two. A dust removal platform (20) is fixedly connected to the rear side of the inner wall of the screening shell (15). The dust removal platform (20) penetrates the rear wall of the screening shell (15) and extends to the outer side of the screening platform (2). The bottom of the inner wall of the screening table (2) is provided with a support shell (13), and the screening shell (15) is fixedly installed above the support shell (13).

5. A grain sorting device according to claim 1, characterized in that: The frustum separation column (25) has a frustum-shaped structure, with the column diameter gradually increasing from the left end to the right end and a taper of 5° to 10°. The annular separation column (26) has a cylindrical structure with a uniform column diameter. The right rear end of the sorting station (1) is fixedly connected to a servo motor 2 (6), the drive end of the servo motor 2 (6) is fixedly connected to an active transmission wheel 1, the right end of the frustum separation column (25) and the right end of the annular separation column (26) are respectively fixedly connected to a driven transmission wheel 1, and the active transmission wheel 1 and the two driven transmission wheels 1 are connected by a transmission belt 1. The output voltage of the high-voltage electrostatic generator is 15kV to 30kV, and it is electrically connected to the metal columns of the frustum separation column (25) and the annular separation column (26), respectively.

6. A grain sorting device according to claim 1, characterized in that: The sorting platform (1) has a front cleaning frame and a rear cleaning frame rotatably connected to the central axis on the left and right sides of its inner wall, respectively. A servo motor (7) is fixedly connected to the front left side of the sorting platform (1). An active transmission wheel (2) is fixedly connected to the drive end of the servo motor (7). A driven transmission wheel (2) is fixedly connected to the left end of the front cleaning frame and the rear cleaning frame, respectively. The active transmission wheel (2) and the two driven transmission wheels (2) are connected by a transmission belt (2). The servo motor 3 (7) has a worm gear 3 sleeved on the outer side of its drive end. The sorting table (1) has a reciprocating screw 1 (27) rotatably connected to the left side of its inner wall. The left end of the reciprocating screw 1 (27) is fixedly connected to a worm wheel 3. The worm gear 3 and the worm wheel 3 mesh to form a worm wheel and worm gear assembly 3. The outer wall of the reciprocating screw (27) is fitted with a connecting platform (28), and the inner wall of the connecting platform (28) is rotatably connected to a cleaning wheel (30). The left end of the cleaning wheel (30) is fixedly connected to a driven gear, and the left end of the inner wall of the sorting platform (1) is fixedly connected to a driven toothed plate. The driven gear meshes with the driven toothed plate.

7. A grain sorting device according to claim 1, characterized in that: It also includes an intelligent control unit, which is electrically connected to servo motor one (5), fan (9), servo motor five (12), hydraulic press two (14), servo motor four (8), hydraulic press one (10), servo motor two (6), servo motor three (7) and high voltage electrostatic generator respectively; The intelligent control unit has a built-in preset parameter library for various grain varieties. By receiving detection signals from various sensors, it automatically adjusts the operating parameters of each driving component to achieve fully automated sorting control.

8. A grain sorting method, employing a grain sorting apparatus according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step S1, Intermittent feeding: The grain to be sorted is fed into the feeding table (4), and the servo motor (5) drives the feeding plate (17) to reciprocate, so that the grain falls evenly and intermittently into the feeding pipe (19) through the feeding gap at the bottom of the feeding plate (17), and then enters the dust removal table (3); Step S2, Spiral Dust Removal: After the grain enters the air separation chamber (11), it slides down along the spiral shell (16) in a spiral trajectory. The fan (9) introduces high-speed airflow into the air separation chamber (11) to form a spiral wind field, which separates the dust and light impurities in the grain and discharges them through the exhaust shell (22). Step S3, Roller Screening: After dust removal, the grain falls into the screening shell (15). The three-layer screening mesh group performs graded screening of the grain. The upper screening mesh group intercepts large particles of impurities, the middle screening mesh group retains normal grains, and the lower screening mesh group intercepts fine sand and gravel. The hydraulic press (14) drives the screening mesh to deflect so that the impurities fall into the dust discharge platform (20) and are discharged. Step S4, Dielectric Sorting: After screening, normal grains fall into the sorting table (1). The high-voltage electrostatic generator causes a high-voltage electrostatic field to be formed on the surface of the frustum separation column (25) and the annular separation column (26). Particles with different dielectric properties are subjected to different polarization forces, resulting in different motion trajectories. The materials are diverted to different channels through the front cleaning frame and the rear cleaning frame to complete the sorting.

9. A grain sorting method according to claim 8, characterized in that: In step S2, the airflow velocity from the first output end of the blower (9) to the lower part of the air separator (11) is 8m / s to 15m / s, and the airflow forms an upward spiral flow field along the spiral shell (16). Servo motor five (12) drives the conical shell (18) to rotate through the worm gear assembly one. The rotation speed is 30r / min to 60r / min. The conical shell (18) drives the auxiliary blades to rotate to enhance the stability of the spiral flow field. The second output end of the fan (9) generates negative pressure to extract the separated dust through the exhaust shell (22).

10. A grain sorting method according to claim 8, characterized in that: In step S3, the hydraulic press (14) drives the transmission gears of each screen (21) to rotate through the drive tooth plate, causing the screen to deflect. The deflection angle range is 0° to 30°. Servo motor four (8) drives the upper and lower screening mesh groups to rotate through worm gear group two, with a rotation speed of 50r / min to 100r / min. Hydraulic press one (10) drives the middle screening mesh group to rotate through worm gear group two, with a rotation speed of 30r / min to 60r / min. Large particles of impurities intercepted by the upper screening mesh group and fine sand and gravel intercepted by the lower screening mesh group fall into the dust discharge platform (20) and are transported by the dust discharge platform (20) to the outside of the screening platform (2) for discharge. In step S4, the frustum separation column (25) has a frustum structure. The material enters from the left end with a smaller diameter and moves to the right along the column surface. The electric field strength gradually changes, realizing progressive grading and sorting. The annular separation column (26) has a cylindrical structure and performs secondary fine selection on the normal grains output from the frustum separation column (25). Servo motor three (7) drives reciprocating screw one (27) to rotate through worm gear group three, which drives connecting platform (28) to move axially. The cleaning wheel (30) on the connecting platform (28) rotates under the meshing action of driven gear and driven tooth plate, and evenly sends the material screened by the annular separation column (26) to the frustum separation column (25).

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