Efficient multistage impurity removal specific gravity type rice screening machine and screening method
By designing the feeding and control components of a high-efficiency multi-stage gravity-type rice screening machine, the problem of uneven feeding was solved, achieving uniform feeding and stable conveying of rice, improving separation accuracy and equipment lifespan, and reducing impurity residue rate and broken rice loss.
Patent Information
- Application Number
- CN202511430305.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-30
- Publication Date
- 2025-11-21
AI Technical Summary
Existing multi-stage impurity removal gravity rice screening machines suffer from uneven feeding, resulting in fluctuations in feed volume and insufficient material conveying stability. This affects separation accuracy and efficiency, especially when the feed is overloaded or underloaded, leading to increased impurity residue and broken rice loss.
A high-efficiency, multi-stage gravity-based rice screening machine with impurity removal was designed. Through the combined use of a feeding component and a control component, uniform feeding and stable conveying of rice are achieved. The feeding component includes a rotating wheel and a pusher plate, while the control component includes a vibrating plate and a transmission rod, ensuring uniform distribution of rice on the screen and preventing clogging.
It achieves uniform and stable output of rice, avoids local pushing and clumping blockage, improves separation accuracy and equipment lifespan, and reduces impurity residue rate and broken rice loss.
Smart Images
Figure CN120984552A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of screening machines, in particular to a high-efficiency multi-stage impurity removal density type rice screening machine and a screening method. BACKGROUND
[0002] As the main grain crop in China, the processing quality of rice is directly related to food safety and market value. Rice screening machines are used for grading and impurity removal of rice to improve the quality of rice. Commonly used are density type rice screening machines. Multi-stage impurity removal density type rice screening machines can realize the grading and removal of light impurities (chaff, broken straw) and heavy impurities (small stones, metal particles) and the accurate grading of whole rice and broken rice through the synergistic effect of "air flow suspension separation + vibration screening". The separation precision and processing efficiency of such equipment directly determine the key quality indicators of finished rice, such as cleanliness and broken rice rate, and have an important impact on the economic benefits of enterprises. In actual production, the impurity removal and grading precision of the equipment is highly dependent on the uniform distribution of the material on the density separation table and the grading screen. Under ideal working conditions, the material should enter the equipment at a stable flow rate (with a fluctuation error of ≤2%) and form a uniform layer of 3-5 cm thick on the screen surface to ensure uniform air flow penetration and effective vibration energy transmission, achieve the stratification effect of light impurities floating, rice in the middle, and heavy impurities sinking, and accurate grading according to particle size. However, the existing multi-stage impurity removal density type rice screening machines generally have uneven feeding problems, which have become a core bottleneck restricting the improvement of their precision. This is manifested in the following three aspects: Inconsistent feeding: The existing equipment mostly uses gravity self-flow feeding or simple conveyor belt feeding, lacking quantitative control mechanisms. When the material level in the raw material hopper changes (e.g., from 1 / 3 of the hopper to full), the material is subjected to gravitational compression, and the instantaneous feeding amount can suddenly increase from 70% to 120% of the design value. When the feeding is overloaded, the thickness of the material layer on the density separation table exceeds 8 cm, and the air flow cannot penetrate the lower layer of material, causing light impurities to remain in the rice layer, and the impurity residue rate increases from 0.5% to more than 2%. When the feeding is underloaded, the thickness of the material layer is less than 2 cm, and the air flow penetrates excessively, causing the broken rice with slightly lighter density to be mistakenly blown into the light impurity channel, and the broken rice loss rate increases from 0.1% to 1%.
[0003] Insufficient material conveying stability: When the impurity content in the raw material fluctuates (e.g., from 3% to 8%) or the moisture content exceeds the standard, the material is prone to form "bridge blockage" in the feeding channel, causing the equipment to stop feeding. If not handled in time, it will affect the processing efficiency and even cause the equipment to overload. SUMMARY
[0004] In view of the uneven feeding problem of the existing technology, a high-efficiency multi-stage impurity removal density type rice screening machine and a screening method are proposed.
[0005] The application provides a high-efficiency multi-stage impurity-removing and specific-gravity rice screening machine and a screening method.
[0006] The technical scheme of the application is as follows: a high-efficiency multi-stage impurity-removing and specific-gravity rice screening machine, comprising a machine body, an upper layer screen and a lower layer screen and a receiving tray arranged in the machine body, a feeding assembly arranged at the top of the machine body, wherein the feeding assembly specifically comprises a mounting plate arranged at the top of the machine body, a material container arranged at the top of the mounting plate, an external connecting table arranged at the side of the material container, a discharging port arranged at the outer side of the external connecting table, a rotating wheel arranged in the external connecting table, a rotating shaft arranged at the inner side of the rotating wheel, a pushing plate arranged at the outer side of the rotating wheel, a transmission wheel arranged at the outer side of the pushing plate, and a control assembly arranged below the material container. The external connecting table is in communication with the material container, the pushing plate is arranged in a circumferential array around the rotating wheel, the rotating shaft penetrates out of the external connecting table, the pushing plate is attached to the inner wall of the external connecting table, and the transmission wheel is located at the outer side of the external connecting table.
[0007] Further, the feeding assembly further comprises a discharging hopper arranged at the side of the material container. The discharging hopper is arranged outside the external connecting table, the lower end of the discharging hopper extends above the upper layer screen, and a ventilation port is arranged above the discharging hopper.
[0008] Further, the feeding assembly further comprises a receiving seat arranged at the outer side of the pushing plate, a receiving groove arranged at the end of the receiving seat away from the rotating wheel, a sleeve arranged in the receiving groove, a top rod and a pushing spring arranged in the sleeve. The receiving seat and the outer side of the pushing plate are arranged in a linear array, one end of the top rod is slidingly inserted into the sleeve, the other end of the top rod extends out of the sleeve to the opening of the receiving groove, and the end of the receiving seat extending out of the sleeve is provided with a circular arc surface.
[0009] Further, the bottom surface of the material container is provided with an inclined surface, the bottom end of the inclined surface is provided with a sedimentation hopper, and the two external connecting tables are located outside the sedimentation hopper.
[0010] Further, the external connecting table is provided with two upper and lower transmission wheels in transmission connection, and the pushing plates at the outer sides of the two rotating wheels are arranged in a staggered manner.
[0011] Further, the control assembly specifically comprises a vibrating plate arranged at the side of the sedimentation hopper and a transmission rod arranged at the outer side of the vibrating plate. The transmission rod extends downward and is attached to the top of the upper layer screen.
[0012] Further, the control assembly further comprises a mounting frame arranged at the top of the machine body, a mounting frame arranged at the inner side of the mounting frame, a screw sleeve arranged at the inner side of the mounting frame, and a pushing rod arranged in the screw sleeve. The screw sleeve is rotatably connected to the mounting frame, and the push rod is divided into two rotatably connected sections, one of which is rotatably connected to the transmission rod, and the other is threadedly connected to the screw sleeve.
[0013] Furthermore, the control component also includes a transfer seat disposed on the top of the upper screen, the top of which is provided with an arc surface that fits against the transfer rod.
[0014] This invention also provides an efficient multi-stage gravity-based rice screening method, comprising the following steps: Feeding: Rice to be screened enters the feeding hopper; Fabric: Activate the dispensing component; the rotating wheel will evenly dispense the rice to be screened. Impurity removal: The rice, after being screened, falls onto the surface of the upper screen and is vibrated to remove impurities; Sieving: Rice is separated into whole rice, large broken rice, medium broken rice, and small broken rice by passing it through a grading sieve with apertures of 2.5mm, 2.0mm, 1.5mm, and 1.0mm.
[0015] The beneficial effects of this invention are: 1. By setting up the feeding component, the rice in the upper screen flows to the outer platform under the action of gravity, and is then blocked by the rotating wheel and the pusher plate. The rice accumulates in the gap between the pusher plates. The variable frequency motor drives the rotating wheel to rotate through the rotating shaft. During the rotation of the rotating wheel, the rice is pushed out by the pusher plate. Since the gap between the pusher plates is fixed, the rotation speed of the rotating wheel is stable. This can make the rice output uniform, stable and controllable, and not affected by the material level in the hopper. At the same time, by conveying the rice through the pusher plate with the same width as the upper screen, the rice can be spread more evenly on the surface of the upper screen, avoiding local pushing.
[0016] 2. By setting a push rod, when the rotating wheel and push plate rotate, the push rod is pressed into the receiving groove by the inner wall of the outer platform. When the push plate rotates to the junction of the outer platform and the hopper, the push spring pushes the push rod out of the receiving groove. The push rod bounces and impacts the rice in the hopper, preventing the rice from clumping and blocking.
[0017] 3. By setting up control components, when the equipment is started, the transmission rod and vibrating plate transmit the vibration of the upper screen to the sedimentation hopper, so that the sedimentation hopper and the upper screen vibrate together, clearing the rice in the upper screen and sedimentation hopper and preventing clumping and blockage.
[0018] 4. By setting a push rod, during normal use, turn the push rod to lift the transfer rod, and the transfer rod flips upward to leave the transfer seat. This avoids the vibration of the upper screen from affecting the feeding component for a long time, reduces the failure rate, and extends the service life. In case of blockage, turn the push rod to press down the transfer rod, and the transfer rod is placed downward on top of the transfer seat, connecting the upper screen and the feeding component. At the same time, the hopper and the sedimentation hopper vibrate synchronously. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 is a perspective view of the present application; Figure 2 is a schematic view of the dispensing assembly of the present application; Figure 3 is a perspective view of the present application Figure 2 is a schematic view of the present application from a second perspective; Figure 4 is an exploded view of the dispensing assembly of the present application; Figure 5 is a schematic view of the discharge hopper of the present application; Figure 6 is a schematic view of the rotating shaft of the present application; Figure 7 is a perspective view of the present application Figure 6 is an enlarged view of portion A of the present application; Figure 8 is a schematic view of the ejector rod of the present application; Figure 9 is a front view of the present application; Figure 10 is a front view of the present application; Figure 11 is a perspective view of the present application Figure 10 is an enlarged view of the dispensing assembly of the present application; Figure 12 is a perspective view of the present application Figure 11 is an enlarged view of portion B of the present application; Figure 13 is a schematic view of the control assembly of the present application; Figure 14 is a perspective view of the present application Figure 13 is a schematic view of the present application from a second perspective.
[0020] In the drawings: 1, body; 2, upper layer screen; 3, lower layer screen; 4, receiving tray; 5, dispensing assembly; 51, mounting plate; 52, holding hopper; 53, external table; 54, discharge port; 55, rotating wheel; 56, rotating shaft; 57, pushing plate; 58, transmission wheel; 59, discharge hopper; 510, storage seat; 511, storage groove; 512, sleeve; 513, ejector rod; 514, pushing spring; 6, control assembly; 61, vibrating plate; 62, transmission rod; 63, mounting frame; 64, mounting frame; 65, screw sleeve; 66, pushing rod; 67, transmission seat. DETAILED DESCRIPTION
[0021] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.
[0022] Example 1, refer to Figures 1-12For the first embodiment of the application, a high-efficiency multi-stage impurity removal and density type rice screening machine is provided, which comprises a machine body 1, an upper layer screen 2 and a lower layer screen 3 and a receiving tray 4 arranged inside the machine body 1, a feeding assembly 5 arranged at the top of the machine body 1, the feeding assembly 5 specifically comprising an installation plate 51 arranged at the top of the machine body 1, a material containing hopper 52 arranged at the top of the installation plate 51, an external connecting table 53 arranged at the side of the material containing hopper 52, a discharge port 54 opened at the outside of the external connecting table 53, a rotating wheel 55 arranged inside the external connecting table 53, a rotating shaft 56 arranged inside the rotating wheel 55, a pushing plate 57 arranged outside the rotating wheel 55, a transmission wheel 58 arranged outside the pushing plate 57, and a control assembly 6 arranged below the material containing hopper 52.
[0023] Specifically, a multi-channel air flow distribution box is arranged inside the machine body 1, the upper layer screen 2 and the lower layer screen 3 are installed with the machine body 1 through movable walls, the upper layer screen 2 and the lower layer screen 3 are connected with vibration machines to control the vibration of the upper layer screen 2 and the lower layer screen 3, the upper layer screen 2 and the lower layer screen 3 are both arranged in an inclined manner, and a pressure sensor is arranged on the surface of the upper layer screen 2; the installation plate 51 is horizontally arranged at the top of the machine body 1 and fixed through bolts, the material containing hopper 52 is welded at the top of the installation plate 51, humidity and material level sensors are arranged inside the material containing hopper 52, the external connecting table 53 is communicated with the material containing hopper 52, the external connecting table 53 is welded at the side of the material containing hopper 52, the external connecting table 53 is in a cylindrical shape and partially overlaps with the material containing hopper 52, the rotating wheel 55 is rotatably connected to the inside of the external connecting table 53 through the rotating shaft 56, the pushing plates 57 are distributed in a circumferential array around the rotating wheel 55, the pushing plates 57 are welded outside the rotating wheel 55, the rotating shaft 56 penetrates out of the external connecting table 53, the width of the rotating wheel 55 and the pushing plates 57 is the same as that of the upper layer screen 2, a variable frequency motor is connected to the outside of the rotating shaft 56, a controller is connected to the outside of the variable frequency motor, the vibration machines, the air flow distribution box, the humidity and material level sensors are electrically connected with the controller, the pushing plates 57 are attached to the inner wall of the external connecting table 53, the transmission wheel 58 is located outside the external connecting table 53, and the transmission wheel 58 is sleeved outside the rotating shaft 56.
[0024] By arranging the feeding assembly 5, the rice in the upper layer screen 2 flows to the external connecting table 53 under the action of gravity and is then blocked by the rotating wheel 55 and the pushing plates 57, the rice is accumulated in the gaps between the pushing plates 57, the variable frequency motor drives the rotating wheel 55 to rotate through the rotating shaft 56, the rice is pushed out by the pushing plates 57 during the rotation of the rotating wheel 55, the rotating speed of the rotating wheel 55 is stable due to the fixed gaps between the pushing plates 57, the rice can be uniformly, stably and controllably output, and is not affected by the material level in the material containing hopper 52, and the rice can be more uniformly laid on the surface of the upper layer screen 2 through the pushing plates 57 which are the same width as the upper layer screen 2, so as to avoid local pushing.
[0025] The feeding assembly 5 further comprises a receiving seat 510 arranged outside the pushing plate 57, a receiving groove 511 opened at an end of the receiving seat 510 away from the rotating wheel 55, a sleeve 512 arranged inside the receiving groove 511, a jacking rod 513 arranged inside the sleeve 512, and a pushing spring 514.
[0026] Specifically, the receiving seat 510 and the pushing plate 57 are integrally formed, the receiving seat 510 is linearly arranged outside the pushing plate 57, the sleeve 512 is screwed into the receiving groove 511, one end of the jacking rod 513 is slidingly inserted into the sleeve 512, the other end of the jacking rod 513 extends out of the sleeve 512 to the opening of the receiving groove 511, the end of the receiving seat 510 extending out of the sleeve 512 is provided with a circular arc surface, one end of the pushing spring 514 is fixed to the inner wall of the sleeve 512, and the other end of the pushing spring 514 is fixed to the jacking rod 513, and the transition arc surfaces are arranged at the joint between the outer connecting table 53 and the material hopper 52 and the opening of the discharging port 54.
[0027] By arranging the jacking rod 513, when the rotating wheel 55 and the pushing plate 57 rotate, the jacking rod 513 is pressed into the receiving groove 511 by the inner wall of the outer connecting table 53, when the pushing plate 57 rotates to the joint between the outer connecting table 53 and the material hopper 52, the pushing spring 514 pushes the jacking rod 513 out of the receiving groove 511, and the jacking rod 513 is impacted on the rice in the material hopper 52, so that the caking and blocking of the rice are avoided.
[0028] Specifically, the bottom surface of the material hopper 52 is provided with an inclined surface, and the bottom end of the inclined surface is provided with a sedimentation hopper, and the two outer connecting tables 53 are located outside the sedimentation hopper, so that the rice is conveniently collected to the outer connecting table 53.
[0029] Specifically, the outer connecting table 53 is provided with two upper and lower outer connecting tables 53, and the two upper and lower transmission wheels 58 are drivingly connected, so that the feeding of the rice is more uniform.
[0030] The feeding assembly 5 further comprises a discharging hopper 59 arranged at the side of the material hopper 52.
[0031] Specifically, the discharging hopper 59 is arranged outside the outer connecting table 53 and is fixed by bolts, the lower end of the discharging hopper 59 extends above the upper layer screen 2, the upper end of the discharging hopper 59 is provided with a ventilation opening, two passages are arranged inside the discharging hopper 59 and correspond to the two outer connecting tables 53, and the lower ends of the two passages converge together, so that the feeding of the rice is facilitated.
[0032] Embodiment 2, with reference to Figures 1-14 The second embodiment is different from the first embodiment in that the control assembly 6 specifically comprises a vibrating plate 61 arranged at the side of the sedimentation hopper, and a transmission rod 62 arranged outside the vibrating plate 61, and the control assembly 6 further comprises a transmission seat 67 arranged at the top of the upper layer screen 2.
[0033] Specifically, the vibrating plate 61 is attached to the surface of the sedimentation hopper and fixed by bolts, the transmission rod 62 is connected to the vibrating plate 61, and the transmission rod 62 extends downward to attach to the surface of the transmission seat 67 on the top of the upper screen 2; the top of the transmission seat 67 is provided with an arc surface attached to the transmission rod 62, so as to increase the contact area of the two, so as to better transmit power and reduce transmission loss.
[0034] By setting the control assembly 6, when the device starts, the transmission rod 62 and the vibrating plate 61 transmit the vibration of the upper screen 2 to the sedimentation hopper, so that the sedimentation hopper and the upper screen 2 follow the vibration, and the rice in the upper screen 2 and the sedimentation hopper is dredged, so as to avoid the situation of clogging.
[0035] The control assembly 6 further comprises a mounting frame 63 arranged on the top of the machine body 1, a mounting frame 64 arranged on the inner side of the mounting frame 63, a screw sleeve 65 arranged on the inner side of the mounting frame 64, and a push rod 66 arranged in the screw sleeve 65.
[0036] Specifically, the mounting frame 63 is fixed on the edge of the top of the machine body 1 by bolts, the mounting frame 64 is slidingly installed on the inner side of the mounting frame 63 and can be fixed by bolts, the screw sleeve 65 is rotatably connected to the mounting frame 64, and the push rod 66 is divided into two sections rotatably connected, one section is rotatably connected to the transmission rod 62, and the other section is threadedly connected to the screw sleeve 65. The connection between the push rod 66 and the transmission rod 62 is provided with a spring pad for reducing the influence of the vibration of the transmission rod 62 on the push rod 66.
[0037] By setting the push rod 66, when normally used, the push rod 66 is turned to lift the transmission rod 62, the transmission rod 62 is turned upward to leave the transmission seat 67, so as to avoid the influence of the vibration of the upper screen 2 on the feeding assembly 5 for a long time, reduce the failure rate, and prolong the service life. When clogging occurs, the push rod 66 is turned to press the transmission rod 62 downward, the transmission rod 62 is placed downward above the transmission seat 67, the upper screen 2 and the feeding assembly 5 are connected, and the material hopper 52 and the sedimentation hopper are vibrated synchronously.
[0038] The remaining structure is the same as that of example 1.
[0039] Example 3, refer to Figure 1 、 Figures 9-10 , which is a fourth embodiment of the present application, provides: a high-efficiency multi-stage impurity removal and screening method for rice, comprising the following steps: Feeding: the rice to be screened enters the material hopper 52, the material level sensor maintains the material volume at 30%-70% of the capacity of the material hopper 52, and the moisture sensor detects the water content. Distributing: the feeding assembly 5 is started, the rotating wheel 55 rotates to uniformly distribute the rice to be screened, and the controller adjusts the rotating speed of the rotating wheel 55 according to the material level in the material hopper 52. When the material level is less than 30%, the rotating speed is increased to 110% of the reference value, and when the material level is greater than 70%, the rotating speed is decreased to 70%. Impurity removal: the rice is dropped on the surface of the upper screen 2, the multi-channel air flow distribution box adjusts the air volume according to the light impurity content, when the light impurity content is greater than 5%, the air volume is increased to 2500 m³ / h; the controller adjusts the parameters of the separation table according to the material layer data: when the material layer is too thick, the inclination is increased by 1° and the vibration frequency is increased by 5 Hz, when the light impurity residue exceeds the standard, the air volume is increased by 10% and the residence time is extended by 2 s. Screening: the rice is separated into whole rice, large broken rice, medium broken rice and small broken rice in turn through the grading screen group with 2.5 mm, 2.0 mm, 1.5 mm and 1.0 mm aperture; when the pressure of the upper screen 2 is greater than 0.3 MPa, high-frequency vibration (60 Hz, 2 s) is triggered and the feeding amount is reduced by 30%. It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and they should be covered in the scope of the claims of the present application.
Claims
1. A high-efficiency multi-stage impurity removal specific gravity rice screening machine, comprising a machine body (1), an upper screen (2), a lower screen (3), and a receiving tray (4) disposed inside the machine body (1), and a feeding assembly (5) disposed on the top of the machine body (1), characterized in that: The dispensing component (5) specifically includes a mounting plate (51) set on the top of the machine body (1), a hopper (52) set on the top of the mounting plate (51), an external platform (53) set on the side of the hopper (52), a discharge port (54) opened on the outside of the external platform (53), a rotating wheel (55) set inside the external platform (53), a rotating shaft (56) set inside the rotating wheel (55), a pusher plate (57) set on the outside of the rotating wheel (55), a transmission wheel (58) set on the outside of the pusher plate (57), and a control component (6) set below the hopper (52). The outer platform (53) is connected to the hopper (52), the pusher plate (57) is arranged in a circular array around the rotating wheel (55), the rotating shaft (56) passes through the outer platform (53), the pusher plate (57) is attached to the inner wall of the outer platform (53), and the transmission wheel (58) is located on the outside of the outer platform (53).
2. The high-efficiency multi-stage impurity removal gravity-type rice screening machine according to claim 1, characterized in that: The dispensing component (5) also includes a discharge hopper (59) disposed on the side of the hopper (52); The discharge hopper (59) covers the outside of the outer platform (53), the lower end of the discharge hopper (59) extends to the top of the upper screen (2), and a ventilation opening is provided above the discharge hopper (59).
3. The high-efficiency multi-stage impurity removal gravity-type rice screening machine according to claim 1, characterized in that: The dispensing assembly (5) also includes a storage seat (510) disposed on the outside of the pusher plate (57), a storage groove (511) opened at the end of the storage seat (510) away from the rotating wheel (55), a sleeve (512) disposed inside the storage groove (511), a push rod (513) and a push spring (514) disposed inside the sleeve (512). The storage base (510) and the push plate (57) are arranged in a linear array on the outside. One end of the push rod (513) is slidably inserted into the sleeve (512), and the other end extends out of the sleeve (512) to the opening of the storage groove (511). The end of the storage base (510) extending out of the sleeve (512) is provided with an arc surface.
4. The high-efficiency multi-stage impurity removal gravity-type rice screening machine according to claim 2, characterized in that: The bottom surface of the hopper (52) is provided with an inclined surface, and a sedimentation hopper is provided at the bottom end of the inclined surface. The two external platforms (53) are located outside the sedimentation hopper.
5. The high-efficiency multi-stage impurity removal gravity-type rice screening machine according to claim 2, characterized in that: The external platform (53) is provided with two upper and lower transmission wheels (58) connected by transmission, and the push plates (57) on the outer sides of the two rotating wheels (55) are staggered.
6. The high-efficiency multi-stage impurity removal gravity-type rice screening machine according to claim 4, characterized in that: The control component (6) specifically includes a vibrating plate (61) disposed on the side of the sedimentation hopper and a transmission rod (62) disposed on the outside of the vibrating plate (61). The transmission rod (62) extends downward and fits against the top of the upper screen (2).
7. The high-efficiency multi-stage impurity removal gravity-type rice screening machine according to claim 6, characterized in that: The control component (6) also includes a mounting bracket (63) disposed on the top of the body (1), a mounting frame (64) disposed inside the mounting bracket (63), a screw sleeve (65) disposed inside the mounting frame (64), and a push rod (66) disposed inside the screw sleeve (65). The screw sleeve (65) is rotatably connected to the mounting frame (64), and the push rod (66) is divided into two rotatably connected sections, one of which is rotatably connected to the transmission rod (62), and the other is threadedly connected to the screw sleeve (65).
8. The high-efficiency multi-stage impurity removal gravity-type rice screening machine according to claim 7, characterized in that: The control component (6) also includes a transfer seat (67) disposed on the top of the upper screen (2), and the top of the transfer seat (67) is provided with an arc surface that fits against the transfer rod (62).
9. A high-efficiency multi-stage gravity-based rice screening method, employing the high-efficiency multi-stage gravity-based rice screening machine as described in claim 1, characterized in that... Includes the following steps: Feeding: Rice to be screened enters the feeding hopper (52); Fabric: Start the feeding component (5), and rotate the wheel (55) to evenly feed the rice to be screened; Impurity removal: The rice that was screened fell onto the surface of the upper screen (2) and was vibrated to remove impurities; Sieving: Rice is separated into whole rice, large broken rice, medium broken rice, and small broken rice by passing it through a grading sieve with apertures of 2.5mm, 2.0mm, 1.5mm, and 1.0mm.