A multi-stage screening device for lychee

Abstract

The utility model discloses a multistage screening device for litchi, including primary screening unit and fine screening unit, and the primary screening unit realizes the primary separation of small particle litchi through the rotary screening mechanism, and the small particle litchi is discharged from the bottom of the hollow box body, and the medium and large particle litchi flows along the second discharge port to the fine screening unit, the fine screening unit adopts the cooperation of the circulating conveying assembly and the gap part, and the medium and large particle litchi after the primary screening is screened twice, and the medium and small particle litchi is separated and is discharged through the third discharge port, and the large particle litchi is continuously driven to the fourth discharge port and is discharged. The primary screening unit realizes dynamic screening through the centrifugal force of the rotary screening mechanism, avoids the accumulation and blockage of litchi, the fine screening unit screens the medium and large fruits through the gap part, and adapts to the sorting demand of different litchi varieties. The rotary screening mechanism avoids vibration impact and reduces the skin damage, the conveying assembly circulates gently, and there is no collision in the litchi sliding process. Multistage screening and discharge port linkage do not need manual intervention, and improve the overall efficiency.

Description

Technical Field

[0001] This utility model relates to the field of agricultural product processing equipment technology, specifically to a multi-stage sieving device for lychees, which is particularly suitable for the production process of further drying lychees after sieving to make dried lychees. Background Technology

[0002] Dried lychees are dried fruit products made by drying fresh lychees. Their main uses include food, medicine, and health benefits. There are two main processing methods: sun-drying and hot-air drying. Sun-drying is less expensive, while hot-air drying produces a better product.

[0003] Dried lychees are a traditional processed product, requiring multiple steps such as sieving, washing, and drying. The precision of the sieving process directly affects the subsequent drying efficiency and the quality of the finished product. Traditional lychee sieving mainly relies on manual labor or simple vibrating sieving devices, which presents the following problems:

[0004] Incomplete sieving: The lychees are of mixed sizes, which leads to uneven heating during drying. Small particles are prone to over-drying and charring, while large particles retain moisture inside, resulting in inconsistent quality of the finished product.

[0005] High mechanical damage: The lychee skin is easily damaged during the traditional vibrating screening process, and it oxidizes and discolors after drying, affecting its appearance and shelf life.

[0006] In existing technologies, some screening equipment uses a single-layer mesh structure or inclined rollers, but the screen openings are fixed and the sorting dimensions are limited, making it impossible to simultaneously handle primary and secondary screening. Therefore, there is an urgent need for a high-efficiency, low-damage multi-stage screening device for litchi. Utility Model Content

[0007] This application provides a multi-stage sieving device for lychees, including a primary sieving unit and a secondary sieving unit. The primary sieving unit uses a rotary screening mechanism to initially separate small lychee particles, which are discharged from the bottom of a hollow box. Medium and large lychee particles flow along a second discharge port to the secondary sieving unit. The secondary sieving unit uses a circulating conveyor assembly in conjunction with a gap section to perform a second sieving of the medium and large lychee particles after the primary sieving. Smaller lychee particles are separated and discharged through a third discharge port, while larger lychee particles continue to be conveyed to a fourth discharge port. The primary sieving unit uses the centrifugal force of the rotary screening mechanism to achieve dynamic sieving, preventing lychee accumulation and blockage. The secondary sieving unit uses the gap section to sieve medium and large fruits, adapting to the sorting needs of different lychee varieties. The rotary screening mechanism avoids vibration and impact, reducing skin damage; the conveyor assembly uses a smooth circulating drive, preventing collisions during lychee sliding. The multi-stage sieving is linked to the discharge ports, requiring no manual intervention and improving overall efficiency.

[0008] The multi-stage sieving device for lychees in this embodiment includes:

[0009] The primary screening unit includes a hollow box, an inlet located at the top of one end of the hollow box, a first outlet located at the bottom of the hollow box, and a second outlet located at the bottom of the other end of the hollow box.

[0010] The hollow box is equipped with a rotating screening mechanism, which includes:

[0011] A rotatable mesh structure and a power component that drives its rotation;

[0012] The mesh structure allows small lychee particles to be discharged from the bottom to the first discharge port, and the mesh structure can filter out large lychee particles and discharge them through the second discharge port.

[0013] A fine screening unit, located downstream of the primary screening unit, includes at least one grading conveying mechanism;

[0014] The at least one hierarchical transmission mechanism includes:

[0015] A cyclic motion transmission assembly and a power component driving its motion, the transmission assembly comprising:

[0016] A third discharge port is located in the middle of the conveying assembly, and a fourth discharge port is located at the end of the conveying assembly. The conveying assembly includes at least one gap portion for circulating transmission. The at least one gap portion corresponds to the position directly above the third discharge port. Lychees discharged from the second discharge port slide down to the at least one gap portion. The gap of the at least one gap portion can allow small and medium-sized lychees to pass through, and the small and medium-sized lychees fall to the third discharge port. The gap of the at least one gap portion can filter out large lychees and transmit them to the fourth discharge port for discharge.

[0017] Furthermore, as a more preferred embodiment of this utility model:

[0018] The rotatable mesh structure includes:

[0019] A conical mesh cylinder, with openings at both ends; the outer periphery of the smaller diameter end of the conical mesh cylinder is rotatably connected to the hollow box body via a first bearing; a radially arranged transmission rod is provided at the larger diameter end of the conical mesh cylinder;

[0020] A rotating shaft is connected to the transmission rod and rotates coaxially with the first bearing; the rotating shaft is rotatably connected to the hollow box through a second bearing, and one end of the rotating shaft extends out of the hollow box;

[0021] The power assembly includes a power motor disposed at one end of the hollow housing; the output shaft of the power motor is connected to the rotating shaft.

[0022] Furthermore, as a more preferred embodiment of this utility model:

[0023] The hollow box is equipped with a feeding funnel at the inlet;

[0024] The feed funnel has its feed end facing upwards, and its discharge end extends into the feed inlet. The feed funnel is equipped with an inclined ramp, allowing lychees to slide into the feed inlet from the inclined ramp under their own gravity, and then be discharged into the rotary screening mechanism.

[0025] Furthermore, as a more preferred embodiment of this utility model:

[0026] The hollow box is provided with an inclined tray directly below the rotary screening mechanism. The length of the inclined tray is adapted to the length of the rotary screening mechanism. One end of the inclined tray on the same side as the feed inlet is a slope bottom. Small lychee particles fall through the mesh onto the inclined tray and flow out along the inclined tray. The outlet is the first discharge port.

[0027] Furthermore, as a more preferred embodiment of this utility model:

[0028] The bottom of the other end of the hollow box is provided with a discharge slide. The top of the discharge slide corresponds to the discharge end of the rotary screening mechanism. The lychees discharged by the rotary screening mechanism fall into the discharge slide and are discharged to the fine screening unit through the discharge slide. The cross-section of the discharge slide is U-shaped.

[0029] Furthermore, as a more preferred embodiment of this utility model:

[0030] It also includes a water pump, and the hollow housing is provided with a nozzle, the nozzle facing the interior of the rotating screening mechanism, and the water pump is connected to the nozzle through a pipe.

[0031] Furthermore, as a more preferred embodiment of this utility model:

[0032] The transmission component includes:

[0033] A support frame, wherein the top and bottom ends of the support frame are respectively rotatably provided with parallel transmission shafts, and the two ends of the transmission shafts are respectively equipped with transmission sprockets.

[0034] A chain, wherein each of the conveyor sprockets on the same side of the support frame is wound around a chain; the two chains rotate synchronously;

[0035] The transmission rods are evenly distributed between the two chains, and the two ends of each transmission rod are connected to the chain body units of the two chains respectively. The transmission rods are parallel to each other in pairs; the gap between adjacent transmission rods forms at least one gap portion.

[0036] Furthermore, as a more preferred embodiment of this utility model:

[0037] The transmission component further includes:

[0038] The first diversion ramp is disposed in the middle of the support frame, with one end extending out of one side of the support frame, and the bottom port of the first diversion ramp forms the third discharge port.

[0039] The second diversion ramp is located at the end of the support frame. The top of the second diversion ramp can receive the large lychee particles that fall back from the transmission rod. The bottom of the second diversion ramp forms the fourth discharge port.

[0040] Furthermore, as a more preferred embodiment of this utility model:

[0041] The transmission component further includes:

[0042] The first fence is provided on both sides of the support frame, and the first fence is used to limit the flow of lychees from both sides of the transmission rod; and / or

[0043] The second fence is provided at the initial end of the support frame. When the lychees are discharged from the second discharge port to the conveying component, the second fence can limit the lychees from falling out at the initial end of the circulation transmission.

[0044] Furthermore, as a more preferred embodiment of this utility model:

[0045] The power component includes:

[0046] A drive motor is mounted on the support frame; a transmission shaft extends to the output shaft of the drive motor and is connected to the output shaft of the drive motor via a coupling.

[0047] Furthermore, as a more preferred embodiment of this utility model: four pulleys are evenly distributed at the bottom of the support frame; the top of the chain body unit of the chain is provided with an inwardly facing ear; the ear is connected to the transmission rod through an L-shaped plate; the transmission rod is a roller, and lychees smaller than the at least one gap can fall more effectively. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0049] Figure 1 This is a three-dimensional schematic diagram of the overall structure of a multi-stage sieving device for lychees in this embodiment.

[0050] Figure 2 This is a half-section diagram of the primary screening unit in this embodiment.

[0051] Figure 3 This is a half-section diagram of the fine screening unit in this embodiment.

[0052] Figure 4 This is a partial structural diagram of the transmission component in this embodiment.

[0053] Figure 5 This is a schematic diagram of the chain mounting L-shaped plate in this embodiment.

[0054] Figure label:

[0055] 100 - Primary screening unit, 110 - Hollow box, 111 - Feed inlet, 112 - First discharge outlet, 113 - Second discharge outlet, 114 - Rotary screening mechanism, 115 - Support frame, 116 - Feed hopper, 1161 - Inclined ramp, 117 - Inclined support plate, 118 - Discharge chute, 119 - Nozzle.

[0056] 1141-Mesh structure, 1142-Power assembly, 41a-Conical mesh cylinder, 41b-Rotating shaft, 41c-First bearing, 41d-Transmission rod, 41e-Second bearing, 42a-Power motor.

[0057] 200 - Fine screening unit, 210 - Grading and conveying mechanism, 211 - Conveying assembly, 2111 - Third discharge port, 2112 - Fourth discharge port, 211a - Gap section, 2113 - Support frame, 2113a - Conveying shaft, 2113b - Conveying sprocket, 2113c - Pulley, 2114 - Chain, 2114a - Chain body unit, 2114b - Folded ear section, 2114c - L-shaped plate, 2115 - Transmission rod, 2115a - Roller, 2116 - First diversion ramp component, 2117 - Second diversion ramp component, 2118 - First fence, 2119 - Second fence, 212 - Power component, 2121 - Drive motor. Detailed Implementation

[0058] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0059] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0060] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0062] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce. Example

[0063] This embodiment aims to address the shortcomings of existing screening equipment, which uses a single-layer mesh structure or inclined rollers. However, these structures have fixed screen openings, limited sorting dimensions, and are prone to mechanical damage, failing to effectively perform both primary and secondary screening. Therefore, referring to… Figure 1-5As shown in the illustration, this application provides a multi-stage sieving device for lychees, including a primary sieving unit and a secondary sieving unit. The primary sieving unit uses a rotary screening mechanism to initially separate small lychee particles, which are discharged from the bottom of the hollow housing. Medium and large lychee particles flow along the second discharge port to the secondary sieving unit. The secondary sieving unit uses a circulating conveyor assembly in conjunction with a gap section to perform a second sieving of the medium and large lychee particles after the primary sieving, separating small and medium lychee particles and discharging them through a third discharge port. Large lychee particles continue to be conveyed to the fourth discharge port. The primary sieving unit uses the centrifugal force of the rotary screening mechanism to achieve dynamic sieving, preventing lychee accumulation and blockage. The secondary sieving unit uses the gap section to sieve medium and large fruits, adapting to the sorting needs of different lychee varieties. The rotary screening mechanism avoids vibration and impact, reducing skin damage; the conveyor assembly uses a smooth circulating drive, preventing collisions during lychee sliding. The multi-stage sieving is linked to the discharge port, requiring no manual intervention and can be directly connected to drying equipment, improving overall efficiency.

[0064] Reference Figure 1 As shown, a multi-stage sieving device for lychees includes: a primary sieving unit 100 and a fine sieving unit 200.

[0065] The primary screening unit 100 includes a hollow box 110, an inlet 111 located at the top of one end of the hollow box 110, a first outlet 112 located at the bottom of the hollow box 110, and a second outlet 113 located at the bottom of the other end of the hollow box 110; the bottom of the hollow box 110 is evenly distributed with support brackets 115.

[0066] The hollow box 110 is equipped with a rotating screening mechanism 114, which includes a rotatable mesh structure 1141 and a power component 1142 that drives its rotation.

[0067] The mesh of the mesh structure 1141 allows small lychee particles to be discharged from the bottom to the first discharge port 112, while the mesh structure 1141 can filter out large lychee particles and discharge them through the second discharge port 113.

[0068] Reference Figure 1 As shown, the fine screening unit 200 is located downstream of the primary screening unit 100 and includes at least one grading conveying mechanism 210; the at least one grading conveying mechanism 210 includes:

[0069] The cyclic motion transmission assembly 211 and the power component 212 that drives its motion, the transmission assembly 211 includes:

[0070] The conveying assembly 211 has a third discharge port 2111 located in the middle and a fourth discharge port 2112 located at the end of the conveying assembly 211. The conveying assembly 211 also includes at least one gap portion 211a for circulating transmission. The at least one gap portion 211a corresponds to the position directly above the third discharge port 2111. The lychees discharged from the second discharge port 113 slide down to the at least one gap portion 211a. The gap of the at least one gap portion 211a can allow small and medium-sized lychees to pass through. The small and medium-sized lychees fall to the third discharge port 2111. The gap of the at least one gap portion 211a can filter out large lychees and transmit them to the fourth discharge port 2112 for discharge.

[0071] Reference Figure 2 As shown, in some embodiments, the rotatable mesh structure 1141 includes a tapered mesh cylinder 41a and a rotating shaft 41b.

[0072] The conical mesh cylinder 41a has openings at both ends; the outer periphery of the smaller diameter end of the conical mesh cylinder 41a is rotatably connected to the hollow box 110 via the first bearing 41c; and a radially arranged transmission rod 41d is provided at the larger diameter end of the conical mesh cylinder 41a.

[0073] Among them, the rotating shaft 41b is connected to the transmission rod 41d and rotates coaxially with the first bearing 41c; the rotating shaft 41b is rotatably connected to the hollow box 110 through the second bearing 41e, and one end of the rotating shaft 41b extends out of the hollow box 110.

[0074] Reference Figure 2 As shown, the power assembly 1142 includes a power motor 42a located at one end of the hollow housing 110; the output shaft of the power motor 42a is connected to the rotating shaft 41b. It should be noted that the rotatable mesh structure 1141 is a conical mesh cylinder 41a (i.e., a cylindrical structure with a small diameter at one end and a large diameter at the other), with the mesh aperture set according to the lychee variety. The conical design allows the lychees to move towards the larger diameter end due to centrifugal force during rotation, while small lychee particles (e.g., 5-15mm) fall through the mesh, achieving dynamic sorting. The small-diameter end of the conical mesh cylinder 41a is rotatably connected to the side wall of the hollow housing 110 via a first bearing 41c, and the large-diameter end is linked to the external rotating shaft 41b via a transmission rod 41d. The rotating shaft 41b is driven by a motor with adjustable speed to adapt to different sorting efficiency requirements.

[0075] Reference Figure 2 As shown, in some embodiments, the hollow housing 110 is equipped with a feed funnel 116 at the feed inlet 111;

[0076] The feed hopper 116 has its feed end facing upwards, and its discharge end extends into the feed inlet 111. The feed hopper 116 is equipped with an inclined ramp 1161, allowing lychees to slide into the feed inlet 111 under their own weight, and then be discharged into the rotary screening mechanism 114. It should be noted that the inclined ramp 1161 (angle 30°~45°) at the feed inlet 111 allows the lychees to slide into the conical mesh cylinder 41a under gravity. The ramp surface is smooth or covered with a flexible material (such as rubber) to reduce collision damage.

[0077] Reference Figure 2 As shown, in some embodiments, the hollow box 110 is provided with an inclined support plate 117 directly below the rotary screening mechanism 114. The length of the inclined support plate 117 is adapted to the length of the rotary screening mechanism 114. One end of the inclined support plate 117 on the same side as the feed inlet 111 has a sloping bottom. Small lychee particles fall through the mesh onto the inclined support plate 117 and flow out along the inclined support plate 117. The outlet is the first discharge port 112. It should be noted that the inclined support plate 117 (inclination angle 10°~20°) is provided below the conical mesh cylinder 41a to receive the small lychee particles and guide them to the first discharge port 112.

[0078] Reference Figure 1-2 As shown, in some embodiments, a discharge chute 118 is provided at the bottom of the other end of the hollow box 110. The top of the discharge chute 118 corresponds to the discharge end of the rotary screening mechanism 114. The lychees discharged by the rotary screening mechanism 114 fall into the discharge chute 118 and are discharged to the fine screening unit 200 through the discharge chute 118. The cross-section of the discharge chute 118 is U-shaped. The large-diameter end outlet is connected to the U-shaped discharge chute 118. Large lychee particles enter the fine screening unit 200 along the chute. The inner wall of the chute is smooth to avoid jamming.

[0079] Reference Figure 2 As shown, in some embodiments, a water pump is also included. The hollow housing 110 is equipped with nozzles 119 facing the interior of the rotating screening mechanism 114. The water pump is connected to the nozzles 119 via a pipe. A high-pressure nozzle 119 is installed at the top of the hollow housing 110, which sprays water into the conical mesh cylinder 41a via the water pump to wash away impurities (such as stems, dirt, dust, or lime powder) from the surface of the lychees. The water spray direction is opposite to the rotation direction of the mesh cylinder, enhancing the cleaning effect.

[0080] Reference Figure 3-5 As shown, in some embodiments, the transmission assembly 211 includes a support frame 2113, a chain 2114, and a transmission rod 2115.

[0081] The top and bottom ends of the support frame 2113 are respectively rotatably provided with parallel transmission shafts 2113a, and the two ends of the transmission shafts 2113a are respectively equipped with transmission sprockets 2113b.

[0082] On the same side of the support frame 2113, the transmission sprockets 2113b are respectively wound around a chain 2114; the two chains 2114 rotate synchronously;

[0083] Reference Figure 3-5 As shown, transmission rods 2115 are evenly distributed between the two chains 2114. The two ends of each transmission rod 2115 are connected to the chain body units 2114a of the two chains 2114, and the transmission rods 2115 are parallel to each other. The gaps between each pair of transmission rods 2115 form at least one gap portion 211a. It should be noted that the conveying assembly 211 consists of multiple parallel transmission rods 2115. The spacing between adjacent rods is dynamically adjusted by adjusting the position of the transmission rods 2115 on the chains 2114 (e.g., three spacing levels: 5mm, 8mm, and 12mm) to adapt to different grading requirements. Small and medium-sized lychee particles (e.g., diameter 20-25mm) fall from the gap portion 211a to the third discharge port 2111, while larger particles (diameter > 25mm) are conveyed by the transmission rods 2115 to the fourth discharge port 2112 at the end.

[0084] Reference Figure 3 As shown, it should be added that the transmission component 211 also includes:

[0085] The first diversion ramp 2116 is disposed in the middle of the support frame 2113, with one end extending out of one side of the support frame 2113, and the bottom port of the first diversion ramp 2116 forming the third discharge port 2111.

[0086] The second diversion ramp 2117 is located at the end of the support frame 2113. The top of the second diversion ramp 2117 can receive the large lychee particles that fall from the transmission rod 2115 in a circulating return flow. The bottom of the second diversion ramp 2117 forms the fourth discharge port 2112.

[0087] Reference Figure 3-4 As shown, it should be noted that the conveying assembly 211 uses a closed chain 2114 for transmission, and the transmission rod 2115 carries the lychee in the top horizontal section and idles in the bottom return section. The transmission speed is adjustable (e.g., 0.5-1.5 m / s) to ensure that the dwell time of the lychee above the gap 211a is controllable.

[0088] Reference Figure 3-4 As shown, in some embodiments, the transmission component 211 further includes:

[0089] The first fence 2118 is provided on both sides of the support frame 2113. The first fence 2118 is used to limit the flow of lychees from both sides of the transmission rod 2115; and / or

[0090] The second guardrail 2119 is provided at the initial end of the support frame 2113. When lychees are discharged from the second discharge port 113 to the conveying assembly 211, the second guardrail 2119 can limit the lychees from falling out at the initial end of the circulating transmission. It should be noted that detachable guardrails (5-10cm high) are provided on both sides of the conveying assembly 211 to prevent lychees from falling from the sides, and a baffle is provided at the initial end to guide the lychees to fall accurately into the area directly above the gap 211a. In some embodiments, a V-shaped diversion ramp is provided at the third discharge port 2111, and small and medium-sized lychees are collected along the ramp. A buffer pad is provided at the end of the ramp of the fourth discharge port 2112 to reduce the impact of falling oversized lychees.

[0091] Reference Figure 1-5 As shown, it should be noted that the grading outlet can be connected to drying equipment.

[0092] First discharge port 112 (small particles); connected to a high-temperature rapid drying channel (temperature 60-70°C, time 2-3 hours), utilizing the large surface area of ​​small particles for rapid dehydration.

[0093] The third discharge port 2111 (small and medium-sized particles): connected to the balanced drying zone (temperature 50-55℃, time 4-5 hours) to ensure uniform evaporation of moisture from the fruit pulp.

[0094] Fourth discharge port 2112 (large particles): connected to a stepped drying chamber (initial temperature 45℃ for slow drying for 2 hours, then increased to 55℃ for drying for 3 hours) to prevent the fruit shells from cracking.

[0095] Reference Figure 4 As shown, it should be added that the power unit 212 includes:

[0096] A drive motor 2121 is mounted on a support frame 2113; a transmission shaft extends to the output shaft of the drive motor 2121 and is connected to the output shaft of the drive motor 2121 via a coupling.

[0097] Reference Figure 3-4 As shown, in some embodiments, four pulleys 2113c are evenly distributed at the bottom of the support frame 2113; each of the four corners of the bottom of the support frame 2113 is equipped with a universal pulley 2113c with a braking function. The pulleys 2113c are made of nylon with rubber coating, which combines wear resistance and shock absorption. The pulleys 2113c are fixed to the mounting base at the bottom of the support frame 2113 by bolts. The mounting base is equipped with a height adjustment screw for balancing the level of the frame. The pulleys 2113c enable the overall movement of the screening device, facilitating connection with drying equipment at different workstations. After the pulleys 2113c are braked and locked, the support frame 2113 is in stable contact with the ground, preventing equipment displacement during the screening process.

[0098] Reference Figure 5 As shown, in some embodiments, each individual link of the chain 2114 has an inwardly facing folded ear 2114b at its top; the folded ear 2114b is stamped at the top of each link, with a central hole whose diameter matches that of the L-shaped plate 2114c bolted on. The folded ear 2114b is connected to the transmission rod 2115 via the L-shaped plate 2114c; the transmission rod 2115 is a roller 2115a, allowing lychees smaller than at least one gap 211a to fall more effectively. The roller 2115a can be inserted into bearing seats at both ends and can rotate freely. The surface of the roller 2115a is covered with a food-grade silicone layer to reduce skin abrasion during lychee rolling.

[0099] Reference Figure 1-5 The following is a description of the specific working process of the multi-stage sieving device used for lychees:

[0100] The mesh size of the conical net cylinder 41a is set according to the litchi variety, the power motor 42a is started, and the rotation speed of the conical net cylinder 41a is adjusted.

[0101] Check whether the inclined ramp 1161 of the feed hopper 116 is unobstructed, and turn on the water pump to pre-clean the inside of the screen cylinder;

[0102] Start the drive motor 2121 of the conveyor assembly 211, set the transmission speed of the chain 2114 to 1.0 m / s, and check the rotation flexibility of the roller 2115a.

[0103] Release the brake on pulley 2113c at the bottom of support frame 2113, move the device to the position between the outlet of the primary screening unit and the inlet of the drying equipment, lock the brake on pulley 2113c and adjust the frame level.

[0104] Lychees slide from the feed funnel 116 into the conical mesh cylinder 41a. The centrifugal force generated by the rotation of the mesh cylinder causes the lychees to disperse towards the larger diameter end.

[0105] Small lychees fall through the mesh into the inclined tray 117 and are discharged from the first discharge port 112 along the ramp.

[0106] Large lychees move toward the end of the rotating screen and enter the fine screening unit through the U-shaped discharge chute 118.

[0107] The water pump sprays water into the inside of the mesh cylinder through the high-pressure nozzle 119. The water flow direction is opposite to the rotation direction of the mesh cylinder, which washes away impurities on the surface of the lychee. The wastewater is discharged from below the first discharge port 112.

[0108] After initial screening, large lychee particles slide from the discharge chute 118 to the initial end of the conveying assembly 211, are limited by the second fence 2119, and are evenly distributed on the roller 2115a.

[0109] Driven by chain 2114, the small and medium-sized lychees move horizontally with roller 2115a and fall from the gap of roller 2115a to the third discharge port 2111.

[0110] Large lychees that cannot pass through the gaps are supported by rollers 2115a and moved to the end by the conveying assembly 211, and discharged through the fourth discharge port 2112.

[0111] The multi-stage sieving device for lychees provided in the embodiments of this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A multi-stage sieving device for lychees, characterized in that, include: The primary screening unit includes a hollow box, an inlet located at the top of one end of the hollow box, a first outlet located at the bottom of the hollow box, and a second outlet located at the bottom of the other end of the hollow box. The hollow box is equipped with a rotating screening mechanism, which includes: A rotatable mesh structure and a power component that drives its rotation; The mesh structure allows small lychee particles to be discharged from the bottom to the first discharge port, and the mesh structure can filter out large lychee particles and discharge them through the second discharge port. A fine screening unit, located downstream of the primary screening unit, includes at least one grading conveying mechanism; The at least one hierarchical transmission mechanism includes: A cyclic motion transmission assembly and a power component driving its motion, the transmission assembly comprising: A third discharge port is located in the middle of the conveying assembly, and a fourth discharge port is located at the end of the conveying assembly. The conveying assembly includes at least one gap portion for circulating transmission. The at least one gap portion corresponds to the position directly above the third discharge port. Lychees discharged from the second discharge port slide down to the at least one gap portion. The gap of the at least one gap portion can allow small and medium-sized lychees to pass through, and the small and medium-sized lychees fall to the third discharge port. The gap of the at least one gap portion can filter out large lychees and transmit them to the fourth discharge port for discharge.

2. The multi-stage sieving device for lychees according to claim 1, characterized in that: The rotatable mesh structure includes: A conical mesh cylinder, with openings at both ends; the outer periphery of the smaller diameter end of the conical mesh cylinder is rotatably connected to the hollow box body via a first bearing; a radially arranged transmission rod is provided at the larger diameter end of the conical mesh cylinder; A rotating shaft is connected to the transmission rod and rotates coaxially with the first bearing; the rotating shaft is rotatably connected to the hollow box through a second bearing, and one end of the rotating shaft extends out of the hollow box; The power assembly includes a power motor disposed at one end of the hollow housing; the output shaft of the power motor is connected to the rotating shaft.

3. The multi-stage sieving device for lychees according to claim 1, characterized in that: The hollow box is equipped with a feeding funnel at the inlet; The feed funnel has its feed end facing upwards, and its discharge end extends into the feed inlet. The feed funnel is equipped with an inclined ramp, allowing lychees to slide into the feed inlet from the inclined ramp under their own gravity, and then be discharged into the rotary screening mechanism.

4. The multi-stage sieving device for lychees according to claim 1, characterized in that: The hollow box is provided with an inclined tray directly below the rotary screening mechanism. The length of the inclined tray is adapted to the length of the rotary screening mechanism. One end of the inclined tray on the same side as the feed inlet is a slope bottom. Small lychee particles fall through the mesh onto the inclined tray and flow out along the inclined tray. The outlet is the first discharge port.

5. The multi-stage sieving device for lychees according to claim 1, characterized in that: The bottom of the other end of the hollow box is provided with a discharge slide. The top of the discharge slide corresponds to the discharge end of the rotary screening mechanism. The lychees discharged by the rotary screening mechanism fall into the discharge slide and are discharged to the fine screening unit through the discharge slide. The cross-section of the discharge slide is U-shaped.

6. The multi-stage sieving device for lychees according to claim 1, characterized in that: It also includes a water pump, and the hollow housing is provided with a nozzle, the nozzle facing the interior of the rotating screening mechanism, and the water pump is connected to the nozzle through a pipe.

7. The multi-stage sieving device for lychees according to claim 1, characterized in that: The transmission component includes: A support frame, wherein the top and bottom ends of the support frame are respectively rotatably provided with parallel transmission shafts, and the two ends of the transmission shafts are respectively equipped with transmission sprockets. A chain, wherein each of the conveyor sprockets on the same side of the support frame is wound around a chain; the two chains rotate synchronously; The transmission rods are evenly distributed between the two chains, and the two ends of each transmission rod are connected to the chain body units of the two chains respectively. The transmission rods are parallel to each other in pairs; the gap between adjacent transmission rods forms at least one gap portion.

8. The multi-stage sieving device for lychees according to claim 7, characterized in that: The transmission component further includes: The first diversion ramp is disposed in the middle of the support frame, with one end extending out of one side of the support frame, and the bottom port of the first diversion ramp forms the third discharge port. The second diversion ramp is located at the end of the support frame. The top of the second diversion ramp can receive the large lychee particles that fall back from the transmission rod. The bottom of the second diversion ramp forms the fourth discharge port.

9. The multi-stage sieving device for lychees according to claim 7, characterized in that: The transmission component further includes: The first fence is provided on both sides of the support frame, and the first fence is used to limit the flow of lychees from both sides of the transmission rod; and / or The second fence is provided at the initial end of the support frame. When the lychees are discharged from the second discharge port to the conveying component, the second fence can limit the lychees from falling out at the initial end of the circulation transmission.

10. The multi-stage sieving device for lychees according to claim 7, characterized in that: The power component includes: a drive motor mounted on the support frame; and a transmission shaft extending to the output shaft of the drive motor and connected to the output shaft of the drive motor via a coupling.

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