A multi-stage coffee bean screening device

Abstract

The utility model provides a kind of coffee bean multistage screening device, belong to screening device technical field, the coffee bean multistage screening device includes: at least two layers of screen frame are sequentially stacked from top to bottom, and screen is tensioned in each layer of screen frame;Elastic misplacement partition plate is clamped between two adjacent layers of screen frame, and elastic misplacement partition plate is integrally formed by food-grade silica gel, the hemispherical particle of convex is uniformly distributed on upper surface, and outer periphery is detachably connected with the inner wall of corresponding screen frame by uniformly distributed omega quick-release buckle, so that adjacent screen is kept misplacement stroke in vertical direction;Bidirectional slope collection groove is arranged at the bottom of the lowermost layer of screen frame, and the bidirectional slope collection groove has a slope surface extending symmetrically to the frame wall on both sides with the center of the groove bottom as the ridge, the slope surface is provided with a wind guide groove, a circular hole is provided at the center of the groove bottom and is circumscribed with a cyclone type heavy impurity discharge port, without increasing fan and peeling equipment, simultaneously improve half-bean rejection rate, silver skin peeling rate and heavy impurity removal rate in coffee bean multistage screening, and reduce energy consumption and pollution risk.

Description

Technical Field

[0001] This utility model belongs to the field of screening device technology, and specifically relates to a multi-stage screening device for coffee beans. Background Technology

[0002] The cleanliness of coffee beans from green beans to pre-roasting directly determines the final cupping flavor, and the first hurdle to cleanliness is multi-stage sieving. A multi-stage coffee bean sieving system typically consists of multiple layers of stacked vibrating screens. The upper layer removes oversized dried fruit shells and broken beans, the middle layer removes standard beans, and the lower layer removes small broken beans and stones. A fan or gravity separator is used to remove lighter impurities. The vibration source excites the screen frame to produce high-frequency reciprocating motion, causing the beans to jump and tumble under inertial force, completing the sieving process based on particle size differences. This structure, due to its large processing capacity, clear grading, and strong continuous operation capability, has become the standard configuration for coffee primary processing lines.

[0003] However, traditional equipment has revealed three structural defects during long-term operation. First, the rigid gaskets or metal spacers used for positioning between the screen frames result in a single vibration direction. The beans only bounce in a plane perpendicular to the screen surface, failing to utilize the difference in center of gravity between flat half-beans and whole round beans, leading to a mixture of half-beans and good beans, requiring manual sorting later. Second, the silver skin is tightly bonded to the bean body, making it difficult to remove by friction alone. Factories have to separately configure a peeling machine and a wind-powered silver skin removal unit after screening, increasing equipment footprint and energy consumption. Third, heavy impurities (sand, metal shavings) concentrate at the end of the bottom screen, requiring an external high-pressure blower to generate lateral airflow to blow them out. The blower not only generates noise and energy consumption but also poses a risk of contamination due to lubricant evaporation. If the blower is turned off, heavy impurities are discharged with the bean flow, causing subsequent color sorter nozzle blockage and increased breakage rate. The industry has tried to improve this by increasing the vibration frequency or increasing the screen inclination angle, but high frequencies exacerbate mechanical fatigue, and large inclination angles shorten the residence time of beans on the screen, thus reducing grading accuracy. Utility Model Content

[0004] In view of this, the present invention provides a multi-stage coffee bean screening device that, without adding a fan or peeling equipment, simultaneously improves the half-bean rejection rate, silverskin peeling rate and heavy impurity removal rate in multi-stage coffee bean screening, while reducing energy consumption and pollution risk.

[0005] This utility model is implemented as follows:

[0006] This utility model provides a multi-stage coffee bean sorting device, comprising:

[0007] At least two layers of sieve frames are stacked from top to bottom, and each layer of sieve frames contains a sieve mesh stretched inside.

[0008] An elastic misalignment partition is sandwiched between two adjacent screen frames. The elastic misalignment partition is integrally molded from food-grade silicone. The upper surface is evenly distributed with raised hemispherical particles. The outer periphery is detachably connected to the inner wall of the corresponding screen frame through evenly distributed Ω-shaped quick-release buckles, so that the adjacent screens maintain a misalignment stroke in the vertical direction.

[0009] A bidirectional inclined collection trough is provided at the bottom of the lowest screen frame. The bidirectional inclined collection trough has an inclined surface that extends symmetrically to the two side frame walls with the center of the trough bottom as the ridge. A wind guide ditch is opened on the inclined surface, and a round hole is opened at the center of the trough bottom and connected to a cyclone-type heavy and mixed discharge port.

[0010] The technical effects of the multi-stage coffee bean screening device provided by this utility model are as follows: The elastic misaligned partition uses its own elasticity to keep adjacent screens vertically misaligned during vibration. When the beans bounce on the surface of the partition, half-beans and broken beans with unstable centers of gravity are thrown out laterally, completing multi-stage screening in one go; at the same time, the hemispherical particles of the partition generate point contact friction with the bean body, peeling off the silver skin in advance and reducing the subsequent peeling process; the bottom bidirectional inclined collection trough guides heavy stones and metal shavings to the cyclone heavy impurity discharge port, which can form cyclone separation by means of vibration inertia, without the need for an external fan, achieving zero-energy heavy impurity removal. The overall system improves the grading accuracy and energy saving level in the same area.

[0011] Based on the above technical solution, the multi-stage coffee bean sorting device of this utility model can be further improved as follows:

[0012] The elastic misaligned partition has a radially protruding fastening edge on its outer periphery. The fixed end of the Ω-shaped quick-release buckle is hinged to the lower edge of the upper screen frame, and the movable end is pressed against the fastening edge, forming a tool-free quick-assembly and disassembly structure.

[0013] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the Ω-shaped quick-release buckle enables the partition plate and the screen frame to be fastened without tools. The installation or replacement of the partition plate can be completed in a few seconds by simply pressing or lifting the buckle, which greatly shortens the downtime for maintenance. At the same time, the buckle applies uniform radial pressure to the outer periphery of the partition plate, ensuring that the partition plate does not loosen or shift during severe vibration, and maintains a stable elastic misalignment stroke over a long period of time.

[0014] Furthermore, the lower surface of the elastic misaligned partition is provided with an annular sealing lip. The sealing lip deforms elastically after being pressed between adjacent screen frames to form a dust barrier seal.

[0015] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the annular sealing lip on the lower surface of the partition deforms elastically after the screen frame is pressed, forming a continuous dust-free barrier. This not only prevents coffee bean fragments and silver foil from entering the gaps between the frames, thus avoiding powder accumulation and mold growth, but also creates pre-compression between the partition and the screen frame, further improving the elastic rebound response speed and enhancing the lateral bean throwing effect.

[0016] Furthermore, the slope surface of the bidirectional inclined collection trough is inclined at an angle to the horizontal plane, and the air guide ditch extends from the ridge to the two side edges, so that the airflow generated by the vibration flows along the air guide ditch to the heavy and mixed discharge port.

[0017] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the slope and the air guide ditch together form a self-guiding channel. The airflow generated by the vibration flows directionally along the ditch, directly blowing the heavy debris falling from the bottom screen to the heavy debris discharge port, reducing the residence time of the debris at the bottom of the ditch and avoiding secondary dust. At the same time, the slope angle allows the heavy debris to slide continuously under the dual action of gravity and airflow, realizing automatic slag discharge without cleaning.

[0018] Furthermore, the heavy impurity discharge outlet includes a tangential inlet section and a downwardly tapered discharge section. The tangential inlet section is tangentially connected to the central circular hole at the bottom of the tank, and is used to form a cyclone separation by utilizing vibration inertia.

[0019] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the tangential inlet section of the cyclone heavy and impurity discharge port can generate rotation of the heavy and impurity-air mixture by utilizing the vibration inertia of the equipment itself. The centrifugal force throws the heavy and impurities to the conical discharge section and falls into the collection bucket. The entire structure has no rotating parts and no additional power, which reduces energy consumption and eliminates oil and noise introduced by the fan, keeping the workshop clean.

[0020] Furthermore, the hemispherical particles of the elastic misaligned partition form a point contact array on the plate surface, which is used to apply lateral bouncing and point friction to the falling coffee beans.

[0021] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the hemispherical particle array changes the contact between the bean and the partition from surface contact to multi-point contact, the instantaneous pressure at the contact point increases, the silver skin is partially torn and peeled off, and at the same time the point contact reduces the frictional temperature rise of the bean surface, avoids oil precipitation, and ensures the flavor of raw beans; the particle protrusions also act as micro-bouncing devices, enhance the lateral throwing effect, and improve the half-bean rejection rate.

[0022] Furthermore, the thickness of the elastic misaligned partition is less than the distance between adjacent sieve frames, allowing the partition to elastically deform up and down during vibration, thus amplifying the lateral displacement of the coffee beans.

[0023] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the thickness of the partition plate is less than the spacing between the frames, so that it is always in a compression-rebound cycle during the vibration cycle. The elastic deformation automatically compensates for the change in the spacing between the frames caused by the sudden change in the amount of beans, prevents the screen frames from directly colliding rigidly, and reduces noise and metal fatigue. At the same time, the rebound energy is released instantaneously, forming a secondary micro-throw, which improves the grading efficiency.

[0024] Furthermore, the bidirectional inclined collection trough and the bottom screen frame are integrally stamped, or can be detachably connected by welding or snap-fit, forming a continuous slope without horizontal gaps.

[0025] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the bidirectional inclined collection trough and the bottom screen frame are integrally formed or detachable without horizontal seams, eliminating the dead corners where powder is trapped in the seams. During cleaning, only the whole thing needs to be rinsed to remove residual powder in one go, meeting the requirements for food-grade rapid line changeover; the seamless structure also avoids the accumulation and blockage of heavy impurities at the seams, ensuring the stability of continuous production.

[0026] Furthermore, the outlet end of the heavy impurity discharge port extends downwards from the bottom of the device to directly connect to the collection container, enabling offline discharge of heavy impurities.

[0027] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the outlet end of the heavy impurity discharge port extends downward and directly connects to the mobile collection bucket. Under the combined action of gravity and cyclone, the heavy impurities fall vertically into the bucket, avoiding the dust escape caused by horizontal conveying. The collection bucket can be replaced without stopping the machine, realizing "online impurity discharge and offline cleaning", and improving the utilization rate of equipment operating time.

[0028] Furthermore, the ratio of the thickness of the elastic misaligned partition to the installation spacing between adjacent screen frames is between 0.05 and 0.25.

[0029] Compared with existing technologies, the beneficial effects of the multi-stage coffee bean screening device provided by this utility model are as follows: While retaining the basic framework of a multi-layer vibrating screen, this utility model introduces a three-in-one structural combination of an elastic misaligned partition, a bidirectional inclined collection trough, and a cyclone-type heavy impurity discharge outlet. This allows the same vibration source to simultaneously produce three functions: grading, peeling, and centrifugal discharge of heavy impurities, without the need for an external fan or additional peeling equipment. The elastic misaligned partition is integrally molded from food-grade silicone. The densely distributed hemispherical particles on its surface transform traditional surface contact into point contact. The beans are subjected to lateral shearing upon falling, and the silver skin cracks prematurely under multi-point micro-tearing action. The elastic recovery of the partition keeps adjacent screens dynamically misaligned. Flat half-beans are thrown laterally away from the screen surface due to the shift in their center of gravity, while whole round beans continue to jump forward, thus completing the shape selection within one vibration stroke. The bidirectional inclined collection trough utilizes the high-frequency inertia of the screen itself to guide heavy impurities falling to the bottom of the trough along a symmetrical inclined path to the central circular hole. A cyclone outlet connected to the circular hole converts the linear inertia into a rotating vortex through a tangential inlet. Under centrifugal force, the heavy impurities slide down the wall and fall into the collection bucket, while the bean flow changes direction due to density differences and returns to the main channel. The entire stone removal process requires no additional power, achieving zero-energy continuous stone removal. Because the partition and screen frame use an Ω-shaped quick-release buckle, maintenance personnel can remove the partition for cleaning without stopping the machine, avoiding cross-contamination of grease and dust. The annular sealing lip on the lower surface of the partition forms an elastic pre-compression after being pressed, preventing dust from entering the gaps between the frames and ensuring the partition always operates within its recoverable deformation range, maintaining stable misalignment stroke and peeling efficiency even after long-term operation. All coffee-contact parts of the machine are made of food-grade materials and have no lubrication points, fundamentally eliminating oil contamination and meeting the stringent cleanliness requirements of high-end coffee production lines. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 An example diagram of a first embodiment of a multi-stage coffee bean sorting device;

[0032] Figure 2 A side view of a first embodiment of a multi-stage coffee bean sorting device;

[0033] Figure 3 An example diagram of a second embodiment of a multi-stage coffee bean sorting device;

[0034] Figure 4 A side view of a second embodiment of a multi-stage coffee bean sorting device;

[0035] The attached diagram lists the components represented by each number as follows:

[0036] 10. Screen frame; 11. Screen mesh; 20. Elastic misaligned partition; 30. Two-way inclined collection trough; 31. Air guide ditch; 32. Heavy and impurity discharge port. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0038] This utility model provides a multi-stage coffee bean sorting device, comprising:

[0039] At least two layers of sieve frames 10 are stacked from top to bottom, and each layer of sieve frame 10 has a sieve mesh 11 tensioned inside;

[0040] An elastic misalignment partition 20 is sandwiched between two adjacent sieve frames 10. The elastic misalignment partition 20 is integrally molded from food-grade silicone. The upper surface is evenly distributed with raised hemispherical particles. The outer periphery is detachably connected to the inner wall of the corresponding sieve frame 10 through evenly distributed Ω-shaped quick-release buckles, so that the adjacent sieves 11 maintain a misalignment stroke in the vertical direction.

[0041] A bidirectional inclined collection trough 30 is provided at the bottom of the lowest screen frame 10. The bidirectional inclined collection trough 30 has an inclined surface that extends symmetrically to the two side frame walls with the center of the bottom of the trough as the ridge. A wind guide ditch 31 is opened on the inclined surface, and a round hole is opened at the center of the bottom of the trough and connected to a cyclone-type heavy and mixed discharge port 32.

[0042] In the above technical solution, the outer periphery of the elastic misaligned partition 20 is provided with a radially protruding fastening edge, the fixed end of the Ω-shaped quick-release buckle is hinged to the lower edge of the upper screen frame, and the movable end is pressed against the fastening edge, forming a tool-free quick disassembly and assembly structure.

[0043] Furthermore, in the above technical solution, the lower surface of the elastic misaligned partition 20 is provided with an annular sealing lip. After the sealing lip is pressed together by the adjacent screen frame 10, it deforms elastically to form a dust barrier seal.

[0044] Furthermore, in the above technical solution, the slope surface of the bidirectional inclined collection trough 30 is inclined at an angle to the horizontal plane, and the air guide trough 31 extends from the ridge to the two side edges, so that the airflow generated by the vibration flows along the air guide trough 31 to the heavy and mixed discharge port 32.

[0045] Furthermore, in the above technical solution, the heavy and mixed discharge port 32 includes a tangential inlet section and a downwardly tapered discharge section. The tangential inlet section is tangentially connected to the central circular hole at the bottom of the tank, and is used to form a cyclone separation by utilizing vibration inertia.

[0046] Furthermore, in the above technical solution, the hemispherical particles of the elastic misaligned partition 20 form a point contact array on the plate surface, which is used to apply lateral bouncing and point friction to the falling coffee beans.

[0047] Furthermore, in the above technical solution, the thickness of the elastic misaligned partition 20 is less than the spacing between adjacent screen frames 10, so that the partition can be elastically deformed up and down during vibration, thereby aggravating the lateral displacement of coffee beans.

[0048] Furthermore, in the above technical solution, the bidirectional inclined collection trough 30 and the bottom screen frame are integrally stamped, or can be detachably connected by welding or snap-fit, forming a continuous slope without horizontal gaps.

[0049] Furthermore, in the above technical solution, the outlet end of the heavy and impurity discharge port 32 extends downward to the bottom of the device for direct connection with the collection container, thereby realizing offline discharge of heavy and impurities.

[0050] Furthermore, in the above technical solution, the ratio of the thickness of the elastic misaligned partition 20 to the installation spacing between adjacent screen frames 10 is between 0.05 and 0.25.

[0051] First embodiment: as follows Figure 1 , Figure 2As shown, this embodiment adopts a three-layer screen frame structure, with screen mesh diameters of 8mm, 6mm, and 4mm from top to bottom. The elastic misalignment partition is made of food-grade silicone, integrally molded, with a thickness of 2mm and surface hemispherical particles with a height of 3mm. The outer perimeter of the partition is fastened to the lower edge of the corresponding screen frame by four evenly distributed Ω-shaped buckles, so that adjacent screens maintain a 5mm vertical misalignment stroke. The bidirectional inclined collection trough is integrally stamped with the bottom screen frame, with an inclination angle of 15°, a guide channel width of 0.8mm, and a central circular hole diameter of 30mm at the bottom of the trough. It is connected to an external cyclone-type heavy and mixed waste discharge port, with the outlet end extending downwards by 80mm and directly inserted into the movable collection bucket.

[0052] A medium-sized coffee plantation primary processing line that can process 30 tons of green beans per day has a compact space and cannot accommodate additional fans and peeling machines.

[0053] After the equipment is in operation, heavy and impurities are automatically discharged into the collection bin without the need for a fan, reducing workshop noise by 8dB and saving approximately 15,000 kWh of electricity per year. Moreover, maintenance only requires 30 seconds to pull out the baffle for rinsing, meeting the needs of switching between multiple varieties and small batches.

[0054] Second embodiment: as follows Figure 3 , Figure 4 As shown, this embodiment employs a four-layer sieve frame structure. The sieve mesh sizes from top to bottom are 10mm, 8mm, 5mm, and 3mm. The thickness of the elastic misaligned partition is 1.5mm, the height of the hemispherical particles is 2.5mm, the thickness of the sealing lip on the outer perimeter of the partition is 0.3mm, and there are four clips. The vertical misalignment stroke between adjacent sieves is 4mm. The bidirectional inclined collection trough is welded to the bottom sieve frame. The inclination angle of the inclination is 12°, the width of the air guide channel is 1mm, the diameter of the central circular hole at the bottom of the trough is 25mm, and the cyclone outlet extends downwards by 100mm and is fitted with a food-grade hose to guide heavy impurities to the outdoor collection box.

[0055] A large-scale export processing plant that can process 20,000 tons of raw soybeans annually needs to operate continuously for 24 hours and has zero tolerance for heavy metals.

[0056] During continuous 24-hour operation, no additional fans or dust removal systems are required; when changing product types, workers can remove the partitions and hoses for online rinsing within 1 minute, achieving zero cross-contamination and meeting the food safety standards for export to the European Union.

[0057] Specifically, the principle of this invention is as follows: When the device is running, the vibrating motor excites the multi-layer screen frame to generate vertical and torsional coupled vibrations through the suspension spring system. The elastic misaligned partition moves synchronously with the upper screen frame due to the snap-fit ​​fixation, but its own elastic modulus is much lower than that of the metal frame, forming a phase lag between the upper and lower limit positions. This lag causes transient vertical misalignment of adjacent screens. The soybeans fall evenly into the uppermost screen through the feed inlet. The husks of soybeans with a diameter larger than the mesh size are intercepted, and the remaining soybeans pass through the screen and collide with the hemispherical particle array of the partition: each particle forms a point contact with the soybean surface, and the contact pressure increases instantaneously, and the bonding force between the husk and the soybean body is locally torn; at the same time, the partition deforms downward elastically to store energy, and releases the reverse acceleration when it rebounds. Flat half-beans, due to their high center of gravity and small moment of inertia, are thrown laterally to the edge of the partition and eventually cross the baffle lip and fall into the specially designed half-bean channel, while whole round beans, due to their low center of gravity and stable rolling, continue to jump forward along the screen surface, achieving shape selection. After repeated point friction and misalignment throwing through multiple partitions, the peeling of the silver skin and the removal of the half-bean are completed in the same vibration cycle, without the need for an additional peeling machine.

[0058] When the bean stream reaches the bottom screen, smaller-sized broken beans pass through along with heavier impurities and fall into the bidirectional inclined collection trough. The symmetrical ridges of the trough divide the material into two downward-sloping streams. The guide channels on the inclined surface induce micro-airflows under high-frequency vibration. These airflows flow along the channels to the central circular hole, forming a gas-solid coupling with the descending heavier impurities. The cyclone outlet connected to the circular hole uses a tangential inlet, instantly converting linear inertia into a rotating vortex. Dense sand and metal shavings are discharged downwards against the wall under centrifugal force, while less dense beans float back to the main screen due to the low-pressure area at the center of the vortex, completing the "inertia-centrifugal" dual separation. The entire process utilizes only the vibration energy of the screen itself, requiring no fan or rotating parts, thus avoiding energy consumption and eliminating the risk of oil contamination. For maintenance, simply open the Ω-shaped quick-release clips to remove the partition and collection trough for flushing. The pre-compression design of the sealing lip ensures that the original elastic parameters are maintained after reinstallation, guaranteeing repeatability over long-term operation.

Claims

1. A multi-stage coffee bean sorting device, characterized in that, include: At least two layers of sieve frames are stacked from top to bottom, and each layer of sieve frames contains a sieve mesh stretched inside. An elastic misalignment partition is sandwiched between two adjacent screen frames. The elastic misalignment partition is integrally molded from food-grade silicone. The upper surface is evenly distributed with raised hemispherical particles. The outer periphery is detachably connected to the inner wall of the corresponding screen frame through evenly distributed Ω-shaped quick-release buckles, so that the adjacent screens maintain a misalignment stroke in the vertical direction. A bidirectional inclined collection trough is provided at the bottom of the lowest screen frame. The bidirectional inclined collection trough has an inclined surface that extends symmetrically to the two side frame walls with the center of the trough bottom as the ridge. A wind guide ditch is opened on the inclined surface, and a round hole is opened at the center of the trough bottom and connected to a cyclone-type heavy and mixed discharge port.

2. The coffee bean multi-stage screening device according to claim 1, characterized in that, The outer periphery of the elastic misaligned partition is provided with a radially protruding fastening edge. The fixed end of the Ω-shaped quick-release buckle is hinged to the lower edge of the upper screen frame, and the movable end is pressed against the fastening edge, forming a tool-free quick-assembly and disassembly structure.

3. The coffee bean multi-stage screening device according to claim 2, characterized in that, The lower surface of the elastic misalignment partition is provided with an annular sealing lip. The sealing lip deforms elastically after being pressed between adjacent screen frames to form a dust barrier seal.

4. The coffee bean multi-stage screening device according to claim 3, characterized in that, The slope of the bidirectional inclined collection trough is inclined at an angle to the horizontal plane, and the air guide ditch extends from the ridge to the two side edges, so that the airflow generated by the vibration flows along the air guide ditch to the heavy and mixed discharge port.

5. The coffee bean multi-stage screening device according to claim 4, characterized in that, The heavy and mixed discharge outlet includes a tangential inlet section and a downwardly tapered discharge section. The tangential inlet section is tangentially connected to the central circular hole at the bottom of the tank, and is used to form a cyclone separation by utilizing vibration inertia.

6. The coffee bean multi-stage screening device according to claim 5, characterized in that, The hemispherical particles of the elastic misaligned partition form a point contact array on the plate surface, which is used to apply lateral bouncing and point friction to the falling coffee beans.

7. The coffee bean multi-stage screening device according to claim 6, characterized in that, The thickness of the elastic misaligned partition is less than the distance between adjacent sieve frames, allowing the partition to elastically deform up and down during vibration, thus amplifying the lateral displacement of the coffee beans.

8. The coffee bean multi-stage screening device according to claim 7, characterized in that, The bidirectional inclined collection trough and the bottom screen frame are integrally stamped, or can be detachably connected by welding or snap-fit, forming a continuous slope without horizontal gaps.

9. A multi-stage coffee bean sorting device according to claim 8, characterized in that, The outlet end of the heavy impurity discharge port extends downwards from the bottom of the device to directly connect to the collection container, enabling offline discharge of heavy impurities.

10. A multi-stage coffee bean sorting device according to claim 9, characterized in that, The ratio of the thickness of the elastic misalignment partition to the installation spacing between adjacent screen frames is between 0.05 and 0.25.

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