Coffee bean preselection device

Abstract

A coffee bean pre-selecting device comprises a pre-screening assembly, a spin-drying assembly and a grading screening assembly, coffee beans sequentially pass through the pre-screening assembly, the spin-drying assembly and the grading screening assembly, the pre-screening assembly is used for pre-selecting the coffee beans, the spin-drying assembly is used for spin-drying the coffee beans, and the grading screening assembly is used for grading the coffee beans; the coffee beans are conveyed into the grading screening assembly, grading operation is conducted on the coffee beans through components in the grading screening assembly, then the graded coffee beans are conveyed to the next procedure, and screening of the coffee beans is completed.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, and particularly relates to a coffee bean pre-selection device. Background Art

[0002] Coffee is one of the three major beverages in the world. It is a beverage made from roasted coffee beans and is one of the main beverages popular in the world, along with cocoa and tea. The coffee commonly consumed daily is made from coffee beans using various different cooking utensils, and coffee beans refer to the kernels inside the fruits of coffee trees.

[0003] Currently, in order to ensure the final flavor of coffee beverages, there are still some coffee made in small workshops. When small workshops screen the picked coffee fruits, they usually use utensils such as water tanks to soak and screen the unpeeled coffee fruits. mainly by using the buoyancy of water to float the coffee fruits with shriveled, unripe, etc. kernels that are not plump on the water surface, and the coffee fruits with plump kernels will sink to the bottom, so as to effectively screen out the coffee fruits with plump kernels. Finally, after the screening of coffee fruits is completed, different coffee fruits are manually fished out respectively.

[0004] The whole process of the above-mentioned manual screening of coffee fruits is all completed by manpower, which consumes a lot of labor and has low efficiency, and has the following defects: 1. Low pre-screening efficiency: The manual flotation method relies on experience to judge maturity, has a large labor intensity and unstable accuracy; most of the existing mechanical screening devices use vibrating screens and are difficult to effectively separate unripe / overripe beans; 2. Poor dehydration effect: Natural drying takes up to 24 - 48 hours and is easily affected by the weather; There are limitations in use. Summary of the Invention In order to solve the deficiencies mentioned in the above-mentioned prior art, the present invention provides a coffee bean pre-selection device.

[0005] The present application proposes a coffee bean pre-selection device, including a pre-screening component, a drying component, and a grading and screening component. The coffee beans pass through the pre-screening component, the drying component, and the grading and screening component in sequence. The pre-screening component pre-selects the coffee beans, the drying component dries the water of the coffee beans, and the grading and screening component grades the coffee beans; The pre-screening component described above includes a box body with an open top. At the bottom outer wall of one side of the box body, a drain pipe with a valve is fixedly connected. On the inner walls of both sides of the box body, a set of support plate groups are respectively fixedly installed. Each set of support plate groups consists of two front and rear support plates. The two support plates in each set of support plate groups are respectively located at the front and rear ends inside the box body. A frame is slidably installed inside the box body. Screws are movably installed on the support plates. Threaded holes are respectively opened at the four corners of the top surface of the frame. The screws pass through the threaded holes and are in threaded cooperation with the threaded holes. A control member for controlling the rotation of the screws is installed on one side of the top of the box body. A fishing net that can be unfolded or retracted is movably installed inside the frame. A discharge pipe is installed at the bottom of the box body.

[0006] Specifically, the control member includes a support base fixedly installed on the top of the box body. A rotary motor is fixedly installed on the top surface of the support base. A first gear is fixedly installed at the top end of the output shaft of the rotary motor. A sprocket is fixedly installed at the top end of the screw. Several sprockets are movably connected by a chain. A second gear is fixedly installed at the top end of one of the screws. The second gear can be meshed and cooperated with the first gear.

[0007] Specifically, a reel is movably installed inside one side of the through groove of the frame through a torsion spring. The fishing net is wound around the reel. Grooves are respectively opened at the inner walls of the front and rear ends of the through groove of the frame. Taking-out grooves are respectively opened at the front and rear ends of the top surface of the other side of the frame. The taking-out grooves are internally communicated with the grooves. Rollers that can move inside the grooves are installed in the grooves. The two rollers are movably connected by a connecting rod. The rollers can be taken out from the taking-out grooves. One side of the connecting rod is fixedly connected with one side of the fishing net. A pushing member for pushing the connecting rod to move horizontally is installed on the top surface of the frame.

[0008] Specifically, the pushing member includes two vertical plates fixedly installed on the top surface of the frame. The two vertical plates are respectively located on both sides of the frame. A lead screw is movably installed between the two vertical plates. A nut is in threaded cooperation with the lead screw. A contact block is fixedly installed at the bottom end of the nut. The bottom end of the contact block is in contact and cooperation with the top surface of the frame. A connecting rod is fixedly installed on the top surface of the connecting rod. Connecting handles are rotatably installed on both sides of the connecting rod. A hook body is fixedly installed at the front end of the connecting handle.

[0009] Specifically, the drying component includes a cylinder body with an open top. A cylinder cover is fitted and installed at the top of the cylinder body. A rotating motor is fixedly installed on the inner wall of the cylinder cover. A net cylinder with an open top is arranged inside the cylinder body in a matching manner. A vertical rod is fixedly installed at the bottom end of the output shaft of the rotating motor. The bottom end of the vertical rod is fixedly connected with the inner wall of the bottom end of the net cylinder. An annular groove with a dovetail cross-section is opened on the inner wall of the cylinder cover. Several sliders with a dovetail cross-section are slidably installed in the annular groove. A fixing rod is fixedly installed at the bottom end of the slider. The bottom end of the fixing rod is fixedly connected with the top surface of the net cylinder.

[0010] Specifically, the grading and screening component includes a screening box. A conveying pipe is fixedly installed at the top of one outer wall of the screening box. A motor is fixedly installed on the inner wall of the top of the screening box. The bottom end of the output shaft of the motor is fixedly installed with a rotating rod. A plurality of filter meshes are fixedly installed on the rotating rod. The mesh diameters of the plurality of filter meshes decrease sequentially from top to bottom. A plurality of windows are opened on the inner wall of the other side of the screening box. One window is in the same horizontal plane as a corresponding one of the filter meshes.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The box body is filled with cleaning water. The coffee beans are poured into the box body from the top opening of the box body. After soaking for a period of time, the ripe fruits fall to the bottom of the box body, and the unripe or overripe fruits will float up. During the soaking process, the fishing net is in a contracted state. After the soaking is over, the fishing net expands to block the through grooves in the frame. Then the frame drives the fishing net to move upward, and the unripe or overripe fruits are fished out of the box body by the fishing net. Then the fruits on the fishing net are cleaned, and the cleaning water in the box body is discharged through the drain pipe. After the cleaning water is discharged, the ripe fruits are discharged from the box body through the discharge pipe. Then the fruits are conveyed to the drying component by a conveying device. The drying component dries the water on the fruits, and then conveys the coffee beans to the grading and screening component. The components in the grading and screening component perform grading operations on the coffee beans, and then the graded coffee beans are respectively conveyed to the next process to complete the screening of the coffee beans. Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0013] Figure 1 is a schematic structural view of the pre-screening component in the present invention; Figure 2 is a schematic structural view of the drying component in the present invention; Figure 3 is a schematic structural view of the grading and screening component in the present application; Figure 4 is Figure 1 the A-direction view of Figure 5 is a three-dimensional schematic view of the drying cylinder; Figure 6 is Figure 4 the partial enlarged view B of Figure 7 is an enlarged structural view of the hook body; Figure 8It is a schematic flow diagram of the present invention. Specific embodiments

[0014] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0015] A coffee bean pre-selection device, as Figure 1 shown, includes a pre-screening component, a drying component, and a grading and screening component. The coffee beans sequentially pass through the pre-screening component, the drying component, and the grading and screening component. The pre-screening component pre-selects the coffee beans, the drying component dries the moisture of the coffee beans, and the grading and screening component grades the coffee beans. The pre-screening component includes a box body 1 with an open top. One side of the bottom outer wall of the box body 1 is fixedly connected to a drain pipe with a valve. On both inner walls of the box body 1, a set of support plate groups 2 are respectively fixedly installed. Each set of support plate groups consists of two front and rear support plates. The two support plates in each set of support plate groups are respectively located at the front and rear ends inside the box body 1. A frame 3 is slidably installed inside the box body 1. A screw rod 4 is movably installed on the support plate. Threaded holes are respectively opened at the four corners of the top surface of the frame 3. The screw rod 4 passes through the threaded holes and is in threaded cooperation with the threaded holes. A control member for controlling the rotation of the screw rod 4 is installed on one side of the top end of the box body 1. A fishing net 5 that can be expanded or contracted is movably installed inside the frame 3. An outlet pipe is installed at the bottom end of the box body 1.

[0016] The mature fruits are discharged from the box body 1 through the outlet pipe, and then the fruits are conveyed into the drying component by a conveying device. A filter screen is installed inside the drain pipe to prevent the fruits from flowing out with the water during drainage. The outer periphery of the frame 3 is in contact and cooperation with the inner wall of the box body 1. Cleaning water is contained inside the box body 1. The coffee beans are poured into the box body 1 through the open top of the box body 1. After soaking for a period of time, the mature fruits fall to the bottom inside the box body 1, and the unripe or overripe fruits will float up. During the soaking process, the fishing net 5 is in a contracted state. After the soaking is over, the fishing net 5 is expanded to block the through slots inside the frame 3. Then the frame 3 drives the fishing net 5 to move upward, and the unripe or overripe fruits are fished out of the box body by the fishing net 5. Then the fruits on the fishing net are cleaned, and the cleaning water inside the box body 1 is discharged through the drain pipe. After the cleaning water is discharged, the mature fruits are discharged from the box body 1 through the outlet pipe, and then the fruits are conveyed into the drying component by a conveying device. The drying component dries the moisture on the fruits, and then conveys the coffee beans into the grading and screening component. The components inside the grading and screening component perform grading operations on the coffee beans, and then the graded coffee beans are respectively conveyed to the next process to complete the screening of the coffee beans.

[0017] Specifically, the control member described in this embodiment includes a support base 6. The support base 6 is fixedly installed at the top end of the box body 1. A rotary motor is fixedly installed on the top surface of the support base 6. A first gear is fixedly installed at the top end of the output shaft of the rotary motor. A sprocket 7 is fixedly installed at the top end of the screw rod 4. Several sprockets 7 are movably connected by a chain. A second gear is fixedly installed at the top end of one of the screw rods 4. The second gear can be meshed and matched with the first gear.

[0018] The heights of the first gear, the second gear, and the sprocket are all higher than the top surface height of the box body 1. The rotary motor controls the rotation of the first gear. The second gear is meshed and matched with the first gear, which can drive the screw rod 4 to rotate. Through the connection between the sprocket and the chain, the remaining screw rods can be driven to rotate. Through the threaded fit between the screw rod and the screw hole, the up and down movement of the frame can be controlled, so that the frame is moved out of the box body, which is convenient for cleaning the fruits on the fishing net.

[0019] Further, a reel is movably installed inside one side of the through slot of the frame 3 through a torsion spring. A fishing net 5 is wound around the reel. Grooves 8 are respectively opened on the inner walls of the front and rear ends of the through slot of the frame 3. Taking-out slots 9 are respectively opened at the front and rear ends of the top surface of the other side of the frame 3. The taking-out slots 9 are internally communicated with the grooves 8. Rollers 10 capable of moving in the grooves are installed in the grooves 8. The two rollers 10 are movably connected by a connecting rod 11. The rollers 10 can be taken out from the taking-out slots 9. One side of the connecting rod 11 is fixedly connected with one side of the fishing net 5. A pushing member capable of pushing the connecting rod to move horizontally is installed on the top surface of the frame 3.

[0020] The material of the torsion spring is stainless steel 316L, which is corrosion-resistant and has a service life ≥ 100,000 times. When the frame is located above the box body 1, at this time, the distance between the connecting rod 11 and the reel is relatively close, and the fishing net 5 is wound around the reel. Then the frame is moved downward so that the frame is located inside the box body. During this process, the connecting rod 11 does not move. After the soaking is over and the fruits have been stratified, at this time, the pushing member pushes the connecting rod 11 to move. The connecting rod 11 moves in a direction away from the reel, that is, the connecting rod moves to the other side of the frame 3. The connecting rod pulls the fishing net to unfold, and the fishing net blocks the through slot of the frame. Then the frame is moved upward to fish the fruits floating on the upper layer. After the frame moves to above the box body 1 again, the pushing member is separated from the connecting rod 11, and the connecting rod 11 is lifted upward. At this time, the rollers 10 are moved out of the taking-out slots 9, and the fishing net can be changed to a vertical state, an inclined state or folded to one side of the box body 1, which is more convenient for cleaning the fruits on the fishing net. After the cleaning is over, the rollers 10 are placed from the taking-out slots 9 into the grooves 8. Under the action of the torsion spring, the reel rotates, and the fishing net 5 is wound around the reel. The rollers 10 roll in the grooves 8, and the connecting rod 11 moves in the direction of the reel, and the through slot of the frame is exposed again for the next use.

[0021] Furthermore, the pusher in this embodiment includes two vertical plates 12. The vertical plates 12 are fixedly installed on the top surface of the frame. The two vertical plates 12 are respectively located on both sides of the frame. A lead screw 13 is movably installed between the two vertical plates 12. A nut is threadedly engaged with the lead screw 13. The bottom end of the nut is fixedly installed with a contact block 14. The bottom end of the contact block 14 is in contact and cooperation with the top surface of the frame. A connecting rod 15 is fixedly installed on the top surface of the connecting rod 11. Connecting handles are rotatably installed on both sides of the connecting rod 15. A hook body 16 is fixedly installed at the front end of the connecting handle.

[0022] The lead screw 13 is equipped with a motor, and the motor is a waterproof motor. The motor is installed on the inner side surface of one of the vertical plates 12. The hook body 16 is as Figure 7 shown. The hook body 16 can be in contact and cooperation with the lead screw 13. And the two hook bodies 16 are located on both sides of the nut. When the frame is above the box body 1, the hook body is taken out from the lead screw. At this time, the roller can be taken out from the groove. After the cleaning is completed, when the connecting rod is close to the reel, at this time the nut is located on one side of the frame. Then the hook body is hooked on the lead screw, and the two hook bodies are respectively located on both sides of the nut. Then the frame enters the box body 1, and the fishing operation is carried out again. Moreover, when the fishing net is unfolded, the lead screw 13 rotates, and the nut moves along the lead screw, driving the hook body and the connecting rod to move, and unfolding the fishing net. After unfolding, due to the self-locking property of the nut and the lead screw itself, the connecting rod can be prevented from being pulled back by the acting force of the torsion spring.

[0023] Furthermore, the drying component in this embodiment includes a cylinder body 17 with an open top end. A cylinder cover is fitted and installed at the top end of the cylinder body 17. A rotating motor is fixedly installed on the inner wall of the cylinder cover. A net cylinder 18 with an open top surface is fitted and arranged in the cylinder body 17. The bottom end of the output shaft of the rotating motor is fixedly installed with a vertical rod 19. The bottom end of the vertical rod 19 is fixedly connected to the inner wall of the bottom end of the net cylinder 18. An annular groove with a dovetail cross-section is opened on the inner wall of the cylinder cover. Several sliders with a dovetail cross-section are slidably installed in the annular groove. The bottom end of the slider is fixedly installed with a fixing rod 20. The bottom end of the fixing rod 20 is fixedly connected to the top surface of the net cylinder 18.

[0024] The vertical rod 19 is installed at the center of the net cylinder 18. A discharge pipe with a valve is installed at the bottom end of the net cylinder 18. A drain pipe is installed at the bottom end of the cylinder body 17. The cylinder cover is lifted from the cylinder body 17 by a lifting device, driving the net cylinder 18 to move out of the cylinder body 17. Then the coffee beans with moisture are poured into the net cylinder 18. The lifting device places the cylinder cover and the net cylinder 18 into the cylinder body 17. After the cylinder cover contacts the top end of the cylinder body 17, the rotating motor controls the vertical rod 19 to rotate, driving the net cylinder 18 to rotate, so that the moisture in the coffee beans is thrown out, and the water droplets are located in the cylinder body 17 and then discharged uniformly. After drying, the lifting device lifts the cylinder cover and the net cylinder 18 upward, so that the net cylinder 18 moves out of the cylinder body. Then the coffee beans are discharged to the conveying device through the discharge pipe and conveyed to the grading and screening component.

[0025] Furthermore, the grading and screening component described in this embodiment includes a screening box 21. A conveying pipe is fixedly installed at the top of one outer wall of the screening box 21. A motor is fixedly installed on the inner wall of the top of the screening box 21. A rotating rod 22 is fixedly installed at the bottom end of the output shaft of the motor. A plurality of filter meshes 23 are fixedly installed on the rotating rod 22. The mesh diameters of the plurality of filter meshes 23 decrease sequentially from top to bottom. A plurality of windows are opened on the inner wall of the other side of the screening box 21. One window is at the same horizontal plane as a corresponding one of the filter meshes 23.

[0026] A counterweight is installed at the top of the rotating rod, and a dynamic balance detection module (such as a vibration sensor) is set. When the amplitude > 0.5 mm, it automatically stops and alarms. An elastic scraper (made of silicone material) is added to the edge of the filter mesh, which contacts the inner wall of the screening box and automatically cleans the coffee beans stuck in the mesh holes during rotation. An opening is provided at the rear end of the screening box 21, through which the coffee beans falling to the bottom of the screening box 21 can be taken out. The rotation speed of the motor is not a high rotation speed. A plurality of guide plates are fixedly installed on the outer wall of the other side of the screening box 21. The guide plates are located below the windows. Air holes can be opened at the top of the screening box. The coffee beans after being dried by centrifugation are conveyed into the conveying pipe through a conveying device and then flow into the screening box 21. The motor drives the rotating rod 22 and the filter meshes 23 to rotate. During the rotation process, coffee beans of different sizes fall downward from the filter meshes, and the coffee beans are graded. Then the coffee beans flow out from the windows and, through the guidance of the guide plates, flow to the conveying device and are then conveyed to the next process to complete the conveying operation of the graded coffee beans.

[0027] A usage method of a coffee bean preselection device S1. Prescreening: Put the coffee beans into the box body 1 for soaking. After the ripe fruits sink, drive the frame 3 to rise through the control member, unfold the fishing net 5 to fish out the floating fruits. The fishing net 5 horizontally unfolds the connecting rod 11 through the lead screw 13. After unfolding, it is fixed by the self-locking of the lead screw, and the torsion spring drives the winding. After draining, the ripe coffee beans are output. S2. Drying: Put the coffee beans into the mesh cylinder 18, rotate the motor to drive the mesh cylinder 18 to dehydrate by centrifugation, and the water is discharged from the bottom of the cylinder body 17. The rotation speed of the mesh cylinder 18 is 800 - 1200 rpm, and the dehydration time is 3 - 5 minutes. The dynamic balance is monitored through a vibration sensor. S3. Grading: The coffee beans enter the screening box 21, the motor drives the multi-layer filter meshes 23 to rotate, and they are output by grading according to the particle size. The elastic scraper at the edge of the filter mesh prevents blockage. The rotation speed of the filter mesh 23 is 20 - 50 rpm, the gradient of the mesh diameter is 8 mm / 6 mm / 4 mm, and the grading error ≤ 2%.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coffee bean pre-selection device, characterized in that: It includes a pre-screening component, a drying component, and a grading and screening component. The coffee beans are sequentially passed through the pre-screening component, the drying component pre-selects the coffee beans, the drying component dries the coffee beans, and the grading and screening component grades the coffee beans. The pre-screening assembly comprises a box body (1), the top of the box body (1) is open, the outer wall of the bottom end of one side of the box body (1) is fixedly connected to a drain pipe with a valve, a group of support plate groups (2) are fixedly installed on the inner walls of both sides of the box body (1), each group of support plate groups is composed of two front and rear support plates, and the two support plates in each group of support plate groups are respectively located at the front and rear ends of the box body (1), a frame (3) is slidably installed in the box body (1), a screw rod (4) is movably installed on the support plate, four corners of the top surface of the frame (3) are respectively provided with screw holes, the screw rod (4) passes through the screw hole and is threadedly matched with the screw hole, a control member for controlling the rotation of the screw rod (4) is installed on one side of the top of the box body (1), a scoop net (5) that can be expanded or retracted is movably installed in the frame (3), and a discharge pipe is installed at the bottom of the box body (1).

2. A coffee bean pre-selection device according to claim 1, characterized in that: The control component comprises a support seat (6), the support seat (6) is fixedly mounted on the top of the box body (1), a rotating motor is fixedly mounted on the top surface of the support seat (6), a first gear is fixedly mounted on the top of the output shaft of the rotating motor, a sprocket (7) is fixedly mounted on the top of the screw rod (4), a plurality of sprocket wheels (7) are movably connected via a chain, a second gear is fixedly mounted on the top of one of the screw rods (4), and the second gear can mesh with the first gear.

3. A coffee bean pre-selection device according to claim 2, characterized in that: A reel is movably mounted inside one side of the through slot of the frame (3) via a torsion spring, and a scooping net (5) is wound around the reel. Grooves (8) are respectively provided on the inner walls at the front and rear ends of the through slot of the frame (3). Take-out grooves (9) are respectively provided at the front and rear ends of the top surface of the other side of the frame (3). The take-out groove (9) is communicated with the inside of the groove (8). A roller (10) capable of moving in the groove is installed in the groove (8). The two rollers (10) are movably connected via a connecting rod (11). The roller (10) can be taken out of the take-out groove (9). One side of the connecting rod (11) is fixedly connected to one side of the scooping net (5). A pushing member capable of pushing the connecting rod to move horizontally is installed on the top surface of the frame (3).

4. A coffee bean pre-selection device according to claim 1 or 3, characterized in that: The pushing member comprises two vertical plates (12), the vertical plates (12) are fixedly mounted on the top surface of the frame, the two vertical plates (12) are respectively located on both sides of the frame, a screw rod (13) is movably mounted between the two vertical plates (12), a nut is provided on the screw rod (13) in a threaded manner, a contact block (14) is fixedly mounted on the bottom end of the nut, the bottom end of the contact block (14) is in contact with the top surface of the frame, a connecting rod (15) is fixedly mounted on the top surface of the connecting rod (11), connecting handles are rotatably mounted on both sides of the connecting rod (15), and a hook body (16) is fixedly mounted on the front end of the connecting handle.

5. The coffee bean pre-selection device according to claim 1, characterized in that: The spin-drying assembly comprises a cylinder (17) with an opening at the top, a cylinder cover is installed at the top of the cylinder (17), a rotating motor is fixedly installed on the inner wall of the cylinder cover, a net cylinder (18) with an opening at the top is arranged in the cylinder (17), a vertical rod (19) is fixedly installed at the bottom end of the output shaft of the rotating motor, the bottom end of the vertical rod (19) is fixedly connected to the inner wall of the bottom end of the net cylinder (18), an annular groove with a dovetail-shaped cross section is provided on the inner wall of the cylinder cover, a plurality of sliding blocks with dovetail-shaped cross sections are slidably installed in the annular groove, a fixing rod (20) is fixedly installed at the bottom end of the sliding block, and the bottom end of the fixing rod (20) is fixedly connected to the top surface of the net cylinder (18).

6. The coffee bean pre-selection device according to claim 1, characterized in that: The grading screening component comprises a screening box (21), a conveying pipe is fixedly mounted on the top of an outer wall of one side of the screening box (21), a motor is fixedly mounted on the inner wall of the top of the screening box (21), a rotating rod (22) is fixedly mounted on the bottom of an output shaft of the motor, a plurality of filter screens (23) are fixedly mounted on the rotating rod (22), the mesh diameters of the plurality of filter screens (23) decrease from top to bottom, and a plurality of windows are provided on the inner wall of the other side of the screening box (21), and a window and a corresponding filter screen (23) are on the same horizontal plane.

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