An internal grading mill for rice processing

Abstract

This invention relates to the field of grinding mill technology, specifically to an internal grading grinding mill for rice processing. It includes a grinding chamber, inside which a grinding mechanism and an internal grading mechanism are rotatably mounted. The grinding mechanism extends to the bottom of the grinding chamber, and the internal grading mechanism extends to the top. When rice flour adheres to the surface of the grading flakes, causing blockage of the airflow channel, an electromagnet is automatically activated, driving the grading roller to move upwards along the grading drive axis. The roller gradually moves to the position of the arc-shaped protrusion. During the continuous rotation of the grading roller, each group of grading flakes vibrates due to the intermittent contact between the roller and the arc-shaped protrusion. The inertial impact of the vibration shakes off the rice flour adhering to the surface of the grading flakes, achieving automatic cleaning without the need for manual cleaning during machine shutdown. This effectively ensures the stability of the gas-solid two-phase flow field inside the equipment, maintains grading accuracy, and improves the particle size uniformity and quality stability of the finished rice flour.

Description

Technical Field

[0001] This invention relates to the field of grinding mill technology, specifically to an internal grading grinding mill for rice processing. Background Technology

[0002] Rice ultrafine grinding is an important process for the deep processing of rice. It can process rice raw materials into ultrafine rice flour, which is widely used in rice and flour products, baked goods, meal replacement powders and other fields, effectively increasing the added value of rice. The internal grading ultrafine grinding mill is the core equipment for rice ultrafine grinding. Its core working principle is to achieve ultrafine grinding of rice particles through mechanical impact and airflow shearing. It also relies on the high-speed rotation of the built-in grading wheel to generate centrifugal grading. By utilizing the coupling effect of airflow and centrifugal force, ultrafine rice flour that meets the particle size requirements is screened out, while coarse particles are returned to the grinding chamber for further grinding. This achieves continuous and fine grinding operation. It has the advantages of small particle size, high grading accuracy and high processing efficiency, and is widely used in rice deep processing production scenarios. Currently, most existing internal grading rice ultrafine mills use fixed-blade grading wheels, which have significant technical defects in actual processing. The ultrafine rice flour particles formed after rice raw material grinding are extremely small in size and have a large specific surface area. Furthermore, rice flour itself contains trace amounts of starch and moisture, exhibiting a certain degree of adhesion and agglomeration. During prolonged continuous operation, the ultrafine rice flour suspended in the airflow easily adheres to the surface of the grading wheel blades and the inside of the wheel's airflow channels. As the operating time increases, the adhered material accumulates and clumps, gradually reducing the airflow cross-sectional area of ​​the grading wheel. This results in narrow airflow channels and poor airflow within the equipment, causing airflow obstruction and unstable wind pressure. This disrupts the gas-solid two-phase flow field balance during grinding and grading, significantly reducing grading and screening accuracy. Consequently, qualified fine powder cannot be discharged smoothly, and coarse powder is not thoroughly screened, resulting in poor uniformity of the finished rice flour particle size and unstable quality. Therefore, we propose an internal grading mill for rice processing to solve the aforementioned technical problems. Summary of the Invention

[0003] The purpose of this invention is to provide an internal grading mill for rice processing to solve the problems mentioned above.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an internal grading mill for rice processing, comprising a milling box, wherein a set of milling mechanisms and a set of internal grading mechanisms are rotatably arranged inside the milling box, the milling mechanisms extend to the bottom of the milling box, and the internal grading mechanisms extend to the top of the milling box, the milling mechanisms are used for milling rice, the internal grading mechanisms are used for controlling the fineness of the rice milling, the internal grading mechanisms are coaxially arranged with the milling mechanisms, and the internal grading mechanisms are located at the upper end of the milling mechanisms, and the internal grading mechanisms are provided with a oscillating and falling component, wherein during the rotation of the internal grading mechanisms, the rice adhering to the surface of the internal grading mechanisms is oscillated and falling back onto the milling mechanisms through the oscillating and falling component.

[0005] As a preferred embodiment of the present invention, the grinding chamber includes a lower chamber, a middle chamber, and an upper chamber. The lower chamber is a cylindrical cavity structure with an open top, and its diameter is much larger than its height. The middle chamber is a cylindrical structure that runs vertically through the lower chamber, and its specifications are adapted to the lower chamber. The lower end of the middle chamber is connected to the upper end of the lower chamber by fasteners. The upper chamber is fixedly mounted on the upper end of the middle chamber. The lower chamber has at least one set of air inlets on its side, which form a through channel between the interior and exterior of the lower chamber. The upper chamber has a set of discharge outlets on its side, which form a through channel between the interior and exterior of the upper chamber. The middle chamber has a set of feed inlets on its side, which form a through channel between the interior and exterior of the middle chamber. An auger conveyor is fixedly mounted at the end of the feed inlet.

[0006] As a preferred embodiment of the present invention, the grinding mechanism includes a grinding disc rotatably disposed inside the lower housing, the bottom of the grinding disc being higher than the top of the air inlet, the outer ring surface of the grinding disc and the inner ring surface of the lower housing being in clearance fit, and the two sets of clearances being 0.1 to 0.3 mm, a number of crushing hammers being fixedly disposed on the top of the grinding disc near its own edge, the number of crushing hammers being distributed in a circumferential array along the outer ring surface of the grinding disc, and a toothed ring being disposed around the number of crushing hammers, the toothed ring being fixedly assembled to the inner ring surface of the middle housing by fasteners.

[0007] As a preferred embodiment of the present invention, the grinding mechanism further includes a grinding disc drive motor fixedly mounted on the bottom of the lower housing. The output shaft of the grinding disc drive motor is fixedly mounted to the center of the grinding disc. The grinding disc has several sets of annularly distributed through air channels at the top near its own edge, and the through air channels are located inside the gear ring.

[0008] As a preferred embodiment of the present invention, the internal grading mechanism includes a grading wheel rotatably disposed on the top of the grinding disc. A plurality of grading blades are rotatably disposed on the top of the grinding disc along its own radial direction. The plurality of grading blades are arranged in a circumferential array along the grading wheel. The grading blades can rotate within an angle range of 15° to 25° along the radial direction of the grinding disc. A plurality of elastic springs are fixedly mounted on the top of the grading wheel. The number and position of the elastic springs correspond one-to-one with the grading blades, and the ends of the elastic springs abut against the side of the corresponding grading blades near the center of the grading wheel. In the initial state, the elastic springs are in an elastic pre-tensioned state.

[0009] As a preferred embodiment of the present invention, the internal grading mechanism further includes a grading drive motor fixedly mounted on the top of the discharge port. A grading drive shaft is fixedly mounted on the lower end of the output shaft of the grading drive motor. The grading drive shaft extends into the interior of the discharge port and is rotatably engaged with the discharge port through a rotating connector. The grading wheel is slidably disposed around the periphery of the grading drive shaft. The grading wheel is axially movable along the grading drive shaft and is circumferentially locked to the grading drive shaft. A diversion ring is sleeved around several sets of grading vanes. The diversion ring is fixedly mounted on the inner wall of the middle box.

[0010] As a preferred embodiment of the present invention, the oscillation and fall-off assembly includes a mounting groove formed on the upper part of the side of the grading blade away from the grading drive shaft, a roller is rotatably mounted inside the mounting groove, and a plurality of sets of annularly distributed arc-shaped protrusions are integrally provided on the lower part of the inner ring surface of the upper box. In the initial state, the inner ring surface of the upper box and the outer ring surface of the roller form a rolling contact pair, and in this state, the arc-shaped protrusions are located on the top of the roller.

[0011] As a preferred embodiment of the present invention, the grinding disc is made of magnetic metal, an electromagnet is fixedly disposed at the bottom of the grinding disc, an upper magnetic block is fixedly disposed at the bottom of the grading wheel, the upper magnetic block is located at the top of the electromagnet, and the upper magnetic block and the electromagnet repel each other magnetically.

[0012] As a preferred embodiment of the present invention, a limiting ring is fixedly provided on the outer ring surface of the grading drive shaft, and a compression spring is sleeved around the grading drive shaft. The compression spring is fixedly assembled between the bottom of the limiting ring and the top of the grading wheel. A spline is formed on the outer ring surface of the compression spring near its lower end. A keyway adapted to the spline specification is formed through the top of the grading wheel, and the keyway engages with the spline. An anti-disengagement block is fixedly assembled at the bottom of the grading drive shaft. In the initial state, the top of the anti-disengagement block abuts against the bottom of the grading wheel.

[0013] As a preferred embodiment of the present invention, a pressure sensor is fixedly installed inside the lower housing, and a pressure sensor is fixedly installed inside the upper housing.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. The pressure difference between the lower and upper chambers is monitored in real time by pressure sensors 1 and 2. When rice flour adheres to the surface of the grading flakes, causing blockage of the airflow channel, the electromagnet is automatically activated to drive the grading wheel to move upward along the grading drive axis. The roller gradually moves to the position of the arc-shaped protrusion. Under the squeezing action of the arc-shaped protrusion, the roller pushes the grading flakes to overcome the preload of the elastic spring and deflect. After the roller passes the arc-shaped protrusion, the grading flakes quickly rebound and reset under the elastic force of the elastic spring. During the continuous rotation of the grading wheel, each group of grading flakes will oscillate due to the intermittent contact between the roller and the arc-shaped protrusion. With the help of the inertial impact of the oscillation, the rice flour adhering to the surface of the grading flakes can be shaken off, realizing automatic cleaning without the need for manual cleaning. This effectively ensures the stability of the gas-solid two-phase flow field inside the equipment, maintains grading accuracy, and improves the particle size uniformity and quality stability of the finished rice flour.

[0015] 2. When the pressure difference between pressure sensor 1 and pressure sensor 2 decreases to below the preset threshold, the external control system cuts off the power to the electromagnet. The electromagnet's magnetic force disappears, the compressed spring releases its elasticity, and pushes the grading wheel down to reset. The device returns to normal grading operation, completing one automatic cleaning cycle. The entire cleaning process does not require machine shutdown and does not affect the overall progress of rice milling. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a perspective structural diagram of the present invention; Figure 3 This is a side sectional view of the grinding chamber in this invention; Figure 4 This is a schematic diagram of the side cross-sectional planar structure of the grinding chamber in this invention; Figure 5 This is a schematic diagram of the grinding mechanism and internal classification mechanism in this invention; Figure 6 This is a schematic diagram of the gear ring structure in this invention; Figure 7 This is a schematic diagram of the grinding disc structure in this invention; Figure 8 This is a schematic diagram of the internal grading mechanism in this invention; Figure 9 This is a schematic diagram of the structure of the graded pinnae in this invention; Figure 10 This is an exploded structural diagram of the graded drive shaft and graded wheel in this invention.

[0017] In the diagram: 100, grinding chamber; 101, lower chamber; 102, air inlet; 103, middle chamber; 104, upper chamber; 105, discharge port; 106, feed port; 200, grinding mechanism; 201, grinding disc; 202, crushing hammer; 203, gear ring; 204, grinding disc drive motor; 205, through air passage; 300, internal classification mechanism; 301, classification wheel; 302, classification blades; 303, classification drive shaft. 304. Staged drive motor; 305. Spline; 306. Keyway; 307. Limiting ring; 308. Compression spring; 309. Diverter ring; 3010. Mounting groove; 3011. Roller; 3012. Arc-shaped protrusion; 3013. Elastic spring; 3014. Upper magnetic block; 3015. Electromagnet; 3016. Anti-detachment block; 400. Drill auger conveyor; 501. Pressure sensor one; 502. Pressure sensor two. Detailed Implementation

[0018] 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.

[0019] Please see Figures 1-10 The technical solution provided by the present invention specifically includes the following embodiments: An internal grading mill for rice processing includes a milling box 100. A set of milling mechanisms 200 and an internal grading mechanism 300 are rotatably arranged inside the milling box 100. The milling mechanisms 200 extend to the bottom of the milling box 100, and the internal grading mechanism 300 extends to the top of the milling box 100. The milling mechanisms 200 are used for milling rice, and the internal grading mechanism 300 is used to control the fineness of the rice powder. The internal grading mechanism 300 is coaxially arranged with the milling mechanisms 200 and is located above the milling mechanisms 200. A oscillating and falling component is provided on the internal grading mechanism 300. During the rotation of the internal grading mechanism 300, the oscillating and falling component oscillates the rice adhering to the surface of the internal grading mechanism 300 back onto the milling mechanisms 200.

[0020] For further details, please refer to [link / reference]. Figure 2 , Figure 3 As shown: The grinding chamber 100 includes a lower chamber 101, a middle chamber 103, and an upper chamber 104. The lower chamber 101 is a cylindrical cavity structure with an open top, and its diameter is much larger than its height. The middle chamber 103 is a cylindrical structure that runs vertically through the lower chamber 101, and its dimensions are adapted to the lower chamber 101. The lower end of the middle chamber 103 is connected to the upper end of the lower chamber 101 by fasteners. The upper chamber 104 is fixedly mounted on the upper end of the middle chamber 103. The lower chamber 101 has at least one set of air inlets 102 on its side, which form a through channel between the interior and exterior of the lower chamber 101. The upper chamber 104 has a set of discharge outlets 105 on its side, which connect the interior of the upper chamber 104 to the exterior of the lower chamber 101. Its exterior forms a through channel. The side of the middle box 103 has a set of feed inlets 106, which form a through channel between the interior and exterior of the middle box 103. A auger conveyor 400 is fixedly installed at the end of the feed inlet 106. Specifically, the auger conveyor 400 transports rice into the middle box 103 through the feed inlet 106, where it is then pulverized by the rotating grinding mechanism 200. At the same time, the inlet of the air inlet 102 is connected to the air supply end of an external air pump. The air pump delivers air into the lower box 101 through the air inlet 102. Then, the air flows upward, passes through the middle box 103 and enters the upper box 104, and finally exits through the outlet 105 (the overall airflow trajectory is shown in the attached instruction manual). Figure 4 In the middle R direction, the crushed powder moves upward with the flowing air, enters the upper box 104, and is finally discharged from the outlet 105, while large rice particles are blocked by the rotating internal grading mechanism 300 and fall back into the middle box 103 to continue to participate in the crushing.

[0021] For further details, please refer to [link / reference]. Figure 5 , Figure 6 , Figure 7 As shown: The grinding mechanism 200 includes a grinding disc 201 rotatably disposed inside the lower housing 101. The bottom of the grinding disc 201 is higher than the top of the air inlet 102. The outer ring surface of the grinding disc 201 and the inner ring surface of the lower housing 101 are in clearance fit, with the two sets of clearances being 0.1 to 0.3 mm. Several sets of crushing hammers 202 are fixedly disposed on the top of the grinding disc 201 near its own edge. The several sets of crushing hammers 202 are distributed in a circumferential array along the outer ring surface of the grinding disc 201, and a toothed ring 203 is disposed around the several sets of crushing hammers 202. The toothed ring 203 is fixedly assembled to the inner ring surface of the middle housing 103 by fasteners. The grinding mechanism 200 also includes a grinding disc drive motor 204 fixedly assembled to the bottom of the lower housing 101. The output shaft of the grinding disc drive motor 204 is fixedly assembled to the center of the grinding disc 201. The grinding disc 201 is located near its own edge. Several sets of annularly distributed through-air channels 205 are opened downwards from the top of the grinding disc 201. The through-air channels 205 are located inside the toothed ring 203. Specifically, the auger conveyor 400 conveys rice to the top of the grinding disc 201 through the feed port 106. The rice is rotated on the surface of the grinding disc 201 by the crushing hammer 202. As the grinding disc 201 rotates, the rice is flung outwards by centrifugal force and continuously collides with the toothed ring 203, thus being crushed into powder. The through-air channels 205 are opened at the edge of the grinding disc 201, which allows the air inside the lower box 101 to flow upwards through the through-air channels 205. This blows the crushed rice powder on the grinding disc 201 upwards and moves with the airflow. Large particles with a weight greater than the airflow carrying capacity cannot move with the airflow and continue to remain at the top of the grinding disc 201, where they are further crushed by the crushing hammer 202.

[0022] For further details, please refer to [link / reference]. Figure 5 , Figure 8 , Figure 9 As shown: The internal grading mechanism 300 includes a grading wheel 301 rotatably mounted on the top of the grinding disc 201. A plurality of grading vanes 302 are rotatably mounted on the top of the grinding disc 201 along its radial direction. These vanes 302 are arranged in a circumferential array along the grading wheel 301. The vanes 302 can rotate radially within a range of 15°-25° along the grinding disc 201. A plurality of elastic springs 3013 are fixedly mounted on the top of the grading wheel 301. The number and position of the elastic springs 3013 correspond one-to-one with the grading vanes 302, and the ends of the elastic springs 3013 are close to the corresponding grading vanes 302 on the grading wheel 301. One side of the center of the circle is in contact with the surface. In the initial state, the elastic spring 3013 is in an elastic pre-tensioned state. The inner grading mechanism 300 also includes a grading drive motor 304 fixedly mounted on the top of the discharge port 105. A grading drive shaft 303 is fixedly mounted on the lower end of the output shaft of the grading drive motor 304. The grading drive shaft 303 extends into the interior of the discharge port 105 and is rotatably engaged with the discharge port 105 through a rotating connector. The grading wheel 301 is slidably disposed around the grading drive shaft 303. The grading wheel 301 is axially movable along the grading drive shaft 303, and the grading wheel 301 and the grading drive shaft 303 are circumferentially... Locked, a group flow ring 309 is fitted around several groups of graded blades 302, and the flow ring 309 is fixedly assembled on the inner wall of the middle box 103; specifically, as the grinding disc 201 rotates, the rice is flung outward by centrifugal force and continuously collides with the toothed ring 203, thus being pulverized into powder. Because the pulverized powder is light, it moves upward under the action of airflow. After passing through the gap between the middle box 103 and the flow ring 309, it enters the top area of ​​the middle box 103, moves along the inner wall of the upper box 104, and passes through the graded gaps between the graded blades 302, and is carried by the airflow into the upper box 104. The powder is finally discharged from the outlet 105. Larger particles, due to their large mass, are agitated by the rotating classifying vanes 302, resulting in greater centrifugal force. They are thrown onto the diverting ring 309 and eventually fall back to the top of the grinding disc 201 for further grinding. When it is necessary to control the fineness of the powder, the rotation speed of the classifying drive motor 304 is controlled, thereby changing the rotation speed of the classifying wheel 301 driving the classifying vanes 302. The higher the rotation speed of the classifying vanes 302, the greater the centrifugal force generated by the agitated airflow, and the finer the powder. Conversely, the smaller the rotation speed, the larger the particle size. This allows for flexible adjustment of the particle size of the finished rice noodles to meet different processing requirements.

[0023] For further details, please refer to [link / reference]. Figure 5 , Figure 9 , Figure 10 As shown: The oscillating and falling assembly includes a mounting groove 3010 located on the upper part of the side of the grading vanes 302 away from the grading drive shaft 303. A roller 3011 is rotatably mounted inside the mounting groove 3010. Several sets of annularly distributed arc-shaped protrusions 3012 are integrally provided on the lower part of the inner ring surface of the upper housing 104. In the initial state, the inner ring surface of the upper housing 104 and the outer ring surface of the discharge port 105 form a rolling contact pair, and in this state, the arc-shaped protrusions 3012 are located on top of the rollers 3011. The grinding disc 201 is made of magnetically conductive metal, and an electromagnet 3015 is fixedly mounted at the bottom of the grinding disc 201. An upper magnetic block 3014 is fixedly mounted at the bottom of the grading wheel 301, located on top of the electromagnet 3015, and the upper magnetic block 3014 and the electromagnet 3015 magnetically repel each other. A limiting ring 307 is fixedly installed on the outer ring surface of the grading drive shaft 303. A compression spring 308 is sleeved around the grading drive shaft 303. The compression spring 308 is fixedly assembled between the bottom of the limiting ring 307 and the top of the grading wheel 301. A spline 305 is opened on the outer ring surface of the compression spring 308 near its lower end. A keyway 306 adapted to the specifications of the spline 305 is opened through the top of the grading wheel 301 downward. The keyway 306 meshes with the spline 305. An anti-detachment block 3016 is fixedly installed at the bottom of the grading drive shaft 303. In the initial state, the top of the anti-detachment block 3016 abuts against the bottom of the grading wheel 301. A first air pressure sensor 501 is fixedly installed inside the lower housing 101, and a second air pressure sensor 502 is fixedly installed inside the upper housing 104.Specifically, with continuous operation, rice grains and rice flour inevitably adhere to the surface of the grading vanes 302, causing the airflow gap between adjacent groups of grading vanes 302 to decrease, obstructing airflow and reducing the air pressure inside the upper chamber 104. At this time, pressure sensor 1 501 detects the air pressure inside the lower chamber 101, and pressure sensor 2 502 detects that the pressure difference inside the upper chamber 104 increases. When the pressure difference reaches a preset threshold, the external control system activates the electromagnet 3015, which then produces... The magnetic force penetrates the grinding disc 201 and pushes the upper magnetic block 3014 upwards, thereby driving the grading wheel 301 and grading vanes 302 to move upwards along the grading drive shaft 303. The upward movement of the grading vanes 302 causes the roller 3011 to move as well. Simultaneously, the compression spring 308 is compressed and stores energy. When the rebound force of the compression spring 308 balances the pushing force of the electromagnet 3015 on the upper magnetic block 3014, the grading wheel 301 stops moving upwards. At this point, the mounting groove 3010 has just moved to the height of the arc-shaped protrusion 3012. The grading flakes 302 continue to rotate with the grading roller 301. As the roller 3011 rolls along the inner circumference of the upper housing 104, it intermittently collides with the arc-shaped protrusion 3012. Under the lateral elastic support of the elastic spring 3013 on the grading flakes 302, the collisions cause the entire grading flakes 302 to vibrate at high frequency, shaking off the rice grains and rice flour adhering to the surface of the grading flakes 302. The shaken-off particles fall back to the top of the grinding disc 201 below under gravity, re-participating in the grinding process, thus completing the self-grinding of the materials adhering to the surface of the grading flakes 302. After cleaning, the airflow efficiency between two adjacent arc-shaped protrusions 3012 is restored, and the pressure difference between pressure sensor 1 501 and pressure sensor 2 502 decreases below the preset threshold. The external control system cuts off the power to electromagnet 3015, the magnetism of electromagnet 3015 disappears, the compression spring 308 releases elastically, pushing the grading wheel 301 to move down and reset. The device returns to normal grading operation, completing one automatic cleaning cycle. The entire cleaning process does not require machine shutdown and does not affect the overall progress of rice milling.

[0024] The working principle of an internal grading mill for rice processing described in this solution is as follows: The air inlet 102 is connected to the external air pump. The air pump delivers air into the lower housing 101 through the air inlet 102. The air then flows upward through the through-flow duct 205, enters the upper housing 104 through the gap between the middle housing 103 and the diverter ring 309, and finally exits through the discharge port 105. The airflow follows a continuous trajectory in the R direction. Then, the grinding disc drive motor 204 and the grading drive motor 304 are started. The grinding disc drive motor 204 drives the grinding disc 201 to rotate, while the grading drive motor 304 drives the grading wheel 301 and several grading blades 302 to rotate. At the same time, the auger conveyor 400 transports rice to the grinding disc through the feed inlet 106. At the top of the grinding disc 201, the rice is rotated on the surface of the grinding disc 201 by the crushing hammer 202. As the grinding disc 201 rotates, the rice is flung outward by centrifugal force and continuously collides with the toothed ring 203, thus being crushed into powder. Because the crushed powder is light, it moves upward under the action of airflow. After passing through the gap between the middle box 103 and the diversion ring 309, it enters the top area of ​​the middle box 103. After moving along the inner wall of the upper box 104, it passes through the grading gap between the grading blades 302 and is carried by the airflow into the interior of the upper box 104. Finally, it is discharged from the discharge port 105. Larger particles are blocked by the grading blades 302 of the rotating ring and fall back to the top of the grinding disc 201 to continue to be crushed. As the process continues, rice grains and rice flour inevitably adhere to the surface of the grading vanes 302, causing the airflow gap between adjacent groups of grading vanes 302 to decrease. This obstructs airflow and reduces the air pressure inside the upper chamber 104. At this time, pressure sensor 1 501 detects the air pressure inside the lower chamber 101, and pressure sensor 2 502 detects the air pressure inside the upper chamber 104. The pressure difference increases. When the pressure difference reaches a preset threshold, the external control system activates electromagnet 3015, which generates magnetic force. The magnetic force penetrates the grinding disc 201, pushing the upper magnetic block 3014 upwards. This causes the grading wheel 301 and grading vanes 302 to move upwards along the grading drive shaft 303. The upward movement of the grading vanes 302 causes the roller 3011 to move as well. Simultaneously, the compression spring 308 is compressed and stores energy. When the rebound force of the compression spring 308 balances the pushing force of the electromagnet 3015 on the upper magnetic block 3014, the grading wheel 301 stops moving upwards. At this point, the mounting groove 3010 has just moved to the height of the arc-shaped protrusion 3012. At this time, the grading... As the grading blades 302 continue to rotate with the grading roller 301, and the roller 3011 rolls along the inner circumference of the upper housing 104, it intermittently collides with the arc-shaped protrusion 3012. Under the lateral elastic support of the elastic spring 3013 on the grading blades 302, the collisions cause the grading blades 302 to vibrate at high frequency, shaking off the rice grains and rice flour adhering to the surface of the grading blades 302. The shaken-off particles fall back to the top of the grinding disc 201 below under gravity, re-participating in the grinding process, thus completing the self-grinding of the materials adhering to the surface of the grading blades 302. After cleaning, the airflow efficiency between two adjacent arc-shaped protrusions 3012 is restored, the pressure difference between pressure sensor 1 501 and pressure sensor 2 502 is reduced to below the preset threshold, the external control system cuts off the power to electromagnet 3015, the magnetic force of electromagnet 3015 disappears, the compression spring 308 releases elastically, pushing the grading wheel 301 to move down and reset as a whole, and the device returns to the normal grading operation state, completing one automatic cleaning cycle. The entire cleaning process does not require machine shutdown and does not affect the overall progress of rice milling.

[0025] 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 variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. An internal grading mill for rice processing, comprising a milling chamber (100), wherein a set of milling mechanisms (200) and a set of internal grading mechanisms (300) are rotatably arranged inside the milling chamber (100), characterized in that: The grinding mechanism (200) extends to the bottom of the grinding box (100), and the internal grading mechanism (300) extends to the top of the grinding box (100). The grinding mechanism (200) is used for grinding rice, and the internal grading mechanism (300) is used to control the fineness of the rice grinding. The internal grading mechanism (300) is coaxially arranged with the grinding mechanism (200), and the internal grading mechanism (300) is located at the upper end of the grinding mechanism (200). The inner grading mechanism (300) is equipped with an oscillation and fall-off component. During the rotation of the inner grading mechanism (300), the rice adhering to the surface of the inner grading mechanism (300) is oscillated and fall-off onto the grinding mechanism (200) by the oscillation and fall-off component.

2. The internal grading mill for rice processing according to claim 1, characterized in that: The grinding chamber (100) includes a lower chamber (101), a middle chamber (103), and an upper chamber (104). The lower chamber (101) is a cylindrical cavity structure with an open top, and the diameter of the lower chamber (101) is much larger than its height. The middle chamber (103) is a cylindrical structure that runs vertically through the lower chamber (101), and its specifications are adapted to the lower chamber (101). The lower end of the middle chamber (103) is connected to the upper end of the lower chamber (101) by fasteners. The upper chamber (104) is fixedly mounted on the upper end of the middle chamber (103). The lower chamber (101)... The lower box (101) has at least one set of air inlets (102) on its side, which form a through channel between the interior and exterior of the lower box (101). The upper box (104) has a set of discharge outlets (105) on its side, which form a through channel between the interior and exterior of the upper box (104). The middle box (103) has a set of feed inlets (106) on its side, which form a through channel between the interior and exterior of the middle box (103). A auger conveyor (400) is fixedly installed at the end of the feed inlet (106).

3. The internal grading mill for rice processing according to claim 2, characterized in that: The grinding mechanism (200) includes a grinding disc (201) rotatably disposed inside the lower housing (101). The bottom of the grinding disc (201) is higher than the top of the air inlet (102). The outer ring surface of the grinding disc (201) and the inner ring surface of the lower housing (101) are in clearance fit, and the two sets of clearances are 0.1 to 0.3 mm. Several sets of crushing hammers (202) are fixedly disposed on the top of the grinding disc (201) near its own edge. The several sets of crushing hammers (202) are distributed in a circumferential array along the outer ring surface of the grinding disc (201). A toothed ring (203) is disposed around the several sets of crushing hammers (202). The toothed ring (203) is fixedly assembled to the inner ring surface of the middle housing (103) by fasteners.

4. The internal grading mill for rice processing according to claim 3, characterized in that: The grinding mechanism (200) also includes a grinding disc drive motor (204) fixedly mounted on the bottom of the lower housing (101). The output shaft of the grinding disc drive motor (204) is fixedly mounted to the center of the grinding disc (201). The grinding disc (201) has several sets of annularly distributed through air passages (205) at the top near its own edge. The through air passages (205) are located inside the gear ring (203).

5. The internal grading mill for rice processing according to claim 4, characterized in that: The internal grading mechanism (300) includes a grading wheel (301) rotatably mounted on the top of the grinding disc (201). The top of the grinding disc (201) is rotatably provided with a number of grading vanes (302) along its own radial direction. The number of grading vanes (302) are arranged in a circumferential array along the grading wheel (301). The grading vanes (302) can rotate within a radial angle range of 15° to 25° along the grinding disc (201). The top of the grading wheel (301) is fixedly equipped with a number of elastic springs (3013). The number and position of the elastic springs (3013) correspond one-to-one with the grading vanes (302). The end of the elastic spring (3013) abuts against the side of the corresponding grading vane (302) near the center of the grading wheel (301). In the initial state, the elastic springs (3013) are in an elastic pre-tensioned state.

6. The internal grading mill for rice processing according to claim 5, characterized in that: The internal grading mechanism (300) also includes a grading drive motor (304) fixedly mounted on the top of the discharge port (105). The lower end of the output shaft of the grading drive motor (304) is fixedly mounted with a grading drive shaft (303). The grading drive shaft (303) extends into the discharge port (105) and rotates with the discharge port (105) through a rotating connector. The grading wheel (301) is slidably disposed on the periphery of the grading drive shaft (303). The grading wheel (301) is axially movable along the grading drive shaft (303) and is circumferentially locked with the grading drive shaft (303). A group of diverting rings (309) are sleeved around the periphery of several groups of grading blades (302). The diverting rings (309) are fixedly mounted on the inner wall of the middle box (103).

7. The internal grading mill for rice processing according to claim 6, characterized in that: The oscillation and fall-off assembly includes a mounting groove (3010) on the upper part of the side of the grading vane (302) away from the grading drive shaft (303). A roller (3011) is rotatably mounted inside the mounting groove (3010). Several sets of arc-shaped protrusions (3012) are integrally provided on the lower part of the inner ring surface of the upper housing (104). In the initial state, the inner ring surface of the upper housing (104) and the outer ring surface of the roller (3011) form a rolling contact pair. In this state, the arc-shaped protrusions (3012) are located on the top of the roller (3011).

8. The internal grading mill for rice processing according to claim 7, characterized in that: The grinding disc (201) is made of magnetic metal. An electromagnet (3015) is fixedly installed at the bottom of the grinding disc (201). An upper magnetic block (3014) is fixedly installed at the bottom of the grading wheel (301). The upper magnetic block (3014) is located on top of the electromagnet (3015), and the upper magnetic block (3014) and the electromagnet (3015) are magnetically repelled.

9. The internal grading mill for rice processing according to claim 8, characterized in that: A limiting ring (307) is fixedly provided on the outer ring surface of the grading drive shaft (303). A compression spring (308) is sleeved around the periphery of the grading drive shaft (303). The compression spring (308) is fixedly assembled between the bottom of the limiting ring (307) and the top of the grading wheel (301). A spline (305) is opened on the outer ring surface of the compression spring (308) near its lower end. A keyway (306) adapted to the specifications of the spline (305) is opened through the top of the grading wheel (301) downward. The keyway (306) meshes with the spline (305). An anti-detachment block (3016) is fixedly assembled on the bottom of the grading drive shaft (303). In the initial state, the top of the anti-detachment block (3016) abuts against the bottom of the grading wheel (301).

10. An internal grading mill for rice processing according to claim 9, characterized in that: A pressure sensor (501) is fixedly installed inside the lower housing (101), and a pressure sensor (502) is fixedly installed inside the upper housing (104).

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