A vacuum gravity sorting device for leaves and stems of plants

Abstract

The present invention discloses a vacuum gravity sorting device for leaves and stems in plant leaves, which relates to the technical field of air separation of plant leaves, including an air separation bin, the air separation bin including a feed port and at least two discharge ports, a vertically arranged feed channel is constructed on the air separation bin, one of the discharge ports is constructed at the bottom of the feed channel, the feed port is opened in the middle of the feed channel, a screening plate is arranged in the feed channel, the screening plate is located above the feed port, and a narrow and long feeding gap is constructed on the screening plate. When leaves and stems are simultaneously attracted by negative pressure to rise in the feed channel, the stems with a relatively hard texture will not be able to pass through the feeding gap under the obstruction of the screening plate, while the relatively flexible leaves will bend and pass through the feeding gap. The present invention realizes the automatic sorting of leaves and stems by arranging a screening plate with a feeding gap in the feed channel, and it is not easy for the two to enter the air separation bin at the same time, so the sorting quality is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of air separation of plant leaves, and in particular to a vacuum gravity separation device for leaves and stems of plant leaves. Background Art

[0002] Products made from plant leaves usually need to be sorted for foreign matter and debris during production. For example, when companies purchase tobacco leaves from tobacco farmers, they often need to sort them. Tobacco leaves need to be graded according to different shapes, especially tobacco stems, which need to be removed from tobacco leaves. Tobacco stems will affect the quality and taste of the final cigarettes, so the industry has set requirements for the stem content of tobacco leaves.

[0003] At present, a Chinese patent with the announcement number CN107457186A discloses a wind separator, including two wind separation units, the discharge port of the previous wind separation unit is connected to the discharge port of the next wind separation unit, and the feed port of the previous wind separation unit is also configured with a first discharge port vertically downward, so that the two wind separation units cooperate to form a first discharge port, a second discharge port, and a third discharge port arranged in sequence. The material is thrown to the top of the first discharge port through a vibrating feeding device, and the heaviest component in the material will be directly discharged from the first discharge port due to insufficient suspension force. As the wind separation proceeds, theoretically, the remaining materials will be discharged from the second discharge port and the third discharge port in order according to the gradient of decreasing weight.

[0004] When winnowing tobacco leaves, in theory, the tobacco stems will be discharged from the first outlet, the larger leaves will be discharged from the second outlet, and the smaller leaves will be discharged from the third outlet. However, the actual situation is sometimes not so ideal. Some large leaves and thin tobacco stems will be sucked upwards together under the action of vacuum negative pressure, which causes the tobacco stems to be discharged from the second outlet, and the sorting quality of tobacco leaves is reduced. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a vacuum gravity sorting device for leaves and stems of plant leaves.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A vacuum gravity sorting device for leaves and stems of plant leaves, comprising an air separation bin, the air separation bin comprising a feed port and at least two discharge ports, the air separation bin being configured with a vertically arranged feed channel, one of the discharge ports being configured at the bottom of the feed channel, the feed port being opened in the middle of the feed channel, a sieve plate being arranged in the feed channel, the sieve plate being located above the feed port, and a narrow feed gap being configured on the sieve plate, the feed gap being adapted to be able to block the stems but allow the leaves to pass through with a bend.

[0008] Preferably, the screening plate comprises two opposing plate bodies, and the material passing gap is formed between the two plate bodies.

[0009] Preferably, a roller is rotatably provided at the end of each plate body, and the material transfer gap is formed between two of the rollers.

[0010] Preferably, the two plates are arranged to be inclined upward relative to each other, so that a material receiving angle that expands toward the side of the feed port is formed between the two plates.

[0011] Preferably, an upper closed unit is further provided in the feed channel, and the upper closed unit is located above the screen plate, and the upper closed unit is adapted to be able to open and close the passage of the feed channel; the upper closed unit is in an open state to allow an airflow to be formed in the feed channel to entrain the material to rise; the upper closed unit is in a closed state to cut off the rising airflow, thereby driving the abutment force of the material against the screen plate to be eliminated.

[0012] Preferably, a lower closing unit is further provided in the feed channel below the feed port, and the lower closing unit is also adapted to be capable of opening and closing the passage of the feed channel.

[0013] Preferably, the upper enclosing unit and the lower enclosing unit may both include a butterfly valve or a gate valve.

[0014] Preferably, a closed band is provided on the outside of the feed channel, the closed band extends into the feed channel and is closed along the circumferential direction, and the feed port and the screen plate are both located in the closed band, an upper air port, a side air port and a lower air port are sequentially opened on the closed band along the circumferential direction, the portion of the closed band located beside the upper air port constitutes the upper closed unit, and the portion of the closed band located beside the lower air port constitutes the lower closed unit; a driving mechanism for driving the closed band to rotate is also provided on the outside of the feed channel.

[0015] Preferably, a mounting frame is vertically movably provided in the feed channel, the screen plate is fixedly provided in the mounting frame, a connecting rod is provided on the side wall of the mounting frame, a guide groove is penetrated through the side wall of the feed channel, the connecting rod extends out of the feed channel from the guide groove, the driving mechanism includes a rotatably arranged driving wheel, the driving wheel is coupled to the closing belt, a tooth portion is also constructed on the driving wheel, a rack is also provided on the end of the connecting rod, and the rack is meshed with the tooth portion.

[0016] Preferably, an installation cavity is provided in the closing belt, and the installation cavity is located at the lower closing unit. A through hole connected to the installation cavity is also provided on the inner wall of the closing belt. Fan blades are rotatably provided in the installation cavity. A driving rod is also elastically provided in the installation cavity. A transmission mechanism is adapted between the driving rod and the rotating shaft of the fan blade. A cable is connected to the driving rod, and the end of the cable away from the driving rod is fixed to the upper closing unit. When the upper closing unit closes the passage of the feed channel, the top of the closing belt is recessed upward under the action of negative pressure, so that the cable can be pulled and the driving rod can be transmitted.

[0017] The beneficial effects of the present invention are:

[0018] 1. When the leaves and stems are simultaneously attracted by the negative pressure and rise in the feed channel, the harder stems will be blocked by the screening plate and cannot pass through the feeding gap, while the more flexible leaves will bend and pass through the feeding gap. Compared with the prior art, the present invention realizes the automatic sorting of leaves and stems by arranging a screening plate with a feeding gap in the feed channel, and it is not easy for both to enter the air separation bin at the same time, so the sorting quality is guaranteed.

[0019] 2. The upper and lower closing units can be used to close the feed channels on both sides of the screen plate. The closure of the upper closing unit can cut off the rising airflow, and then the material adhering to the bottom of the screen plate will automatically fall under the action of gravity, thereby realizing the automatic discharge of the screened stems without starting or stopping the fan of the air separation bin; the lower closing unit can receive the fallen material, especially prevent the blades from being discharged from the discharge port. After the upper closing unit is reopened, the blades can be adsorbed and raised again. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of an embodiment;

[0021] Figure 2 It is a structural schematic diagram of the closed belt;

[0022] Figure 3 for Figure 2 A magnified view of part A;

[0023] Figure 4 is a schematic diagram of the structure of the driving rod;

[0024] Figure 5 Schematic diagram of the operating status of the closed belt.

[0025] Figure numerals: 1. air separation bin; 2. feed port; 3. discharge port; 4. feed channel; 5. screening plate; 6. feeding gap; 7. plate body; 8. roller; 9. upper closing unit; 10. lower closing unit; 11. closing belt; 12. upper air outlet; 13. side feed port; 14. lower air outlet; 15. driving mechanism; 16. mounting frame; 17. connecting rod; 18. guide groove; 19. driving wheel; 20. tooth portion; 21. rack; 22. mounting cavity; 23. through hole; 24. fan blade; 25. driving rod; 26. cable; 27. spring. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0027] like Figures 1 to 5 As shown, a vacuum gravity sorting device for leaves and stems of plant leaves includes a wind selection bin 1 having a feed port 2 and at least two discharge ports 3. For example, the wind selection bin 1 may have two wind selection units, as disclosed in the patent document with publication number CN107457186A, which is incorporated herein by reference. Among them, as the front-order wind selection unit, that is, the front-order feed port 2 of the wind selection bin 1 is configured with a feed channel 4 arranged vertically on one side, and the feed port 2 is configured to be opened in the middle of the feed channel 4, and one of the discharge ports 3 is configured at the bottom of the feed channel 4.

[0028] Under the action of the fan, a relative vacuum negative pressure is formed in each air separation unit, thereby forming an upward airflow in the feed channel 4. When sorting materials, the materials can be fed into the feed channel 4 from the feed port 2 under the conveyance of the vibrating feeding device, and then the relatively light materials will rise into the air separation unit under the entrainment of the upward airflow. The relatively heavy materials are directly discharged from the discharge port 3 at the bottom of the feed channel 4 under the action of gravity.

[0029] For example, when sorting tobacco leaves, lighter leaves will rise, while heavier stems will fall and be discharged. However, in order to ensure that all tobacco leaves rise as much as possible, the fan of the previous air sorting unit needs to maintain a large suction force so that both large and small tobacco leaves can be sucked in. This will cause some large leaves and thin stems to be attracted at the same time. This is because the two have similar suspension performance in the airflow, which will eventually increase the stem content in the tobacco leaves.

[0030] In this regard, in the present invention, a screen plate 5 is further provided in the feed channel 4, and the screen plate 5 is provided above the feed port 2. In addition, a narrow and long feed gap 6 is also constructed on the screen plate 5. The rising material in the feed channel 4 will pass through the screen plate 5, so the harder tobacco stems will not be able to pass through the feed gap 6 due to the obstruction of the screen plate 5, while the more flexible tobacco leaves will bend and pass through the feed gap 6.

[0031] In some examples, the screening plate 5 may be a single plate body 7 obliquely arranged in the feed channel 4, and the above-mentioned feed gap 6 is formed by the interval between the end of the plate body 7 and the inner wall of the feed channel 4. And the plate body 7 may preferably be a mesh structure to minimize the influence on the normal passage of the airflow.

[0032] In other examples, the screening plate 5 may be two opposing plate bodies 7, and the above-mentioned material gap 6 is formed by the interval between the two plate bodies 7. In any example, the end of the plate body 7 may preferably be rotatably provided with a roller 8, and the material gap 6 is formed between the two opposing rollers 8, or between the roller 8 and the inner wall of the feed channel 4. Under the rotation guidance of the roller 8, the tobacco leaves are not easily damaged when they pass through the curved path.

[0033] For example, the two plates 7 can also be adapted to be arranged to be inclined upward relative to each other, so that a material receiving angle that gradually expands toward the side of the feed port 2 can be formed between the two plates 7. Driven by the rising airflow, the materials are more likely to converge to the middle material gap 6 under the guidance of the two plates 7 and achieve the purpose of screening.

[0034] In a preferred example, the width of the feed gap 6 can be selected to be 1.5-2 mm. In this way, tobacco stems with a diameter greater than 1.5-2 mm can be screened out, so that the stem content of tobacco leaves is further reduced. This is because, under normal circumstances, the stem content of tobacco leaves refers to the percentage of the mass of tobacco stems with a diameter greater than 1.5 mm to the mass of the tobacco leaf sample. Under the screening effect of the feed gap 6, most of the tobacco stems with a diameter greater than 1.5 mm in the tobacco leaves can be screened out.

[0035] In some embodiments, an upper closing unit 9 and a lower closing unit 10 are respectively arranged on the upper and lower sides of the sieve plate 5 in the feed channel 4, and the lower closing unit 10 is particularly adapted to be located below the feed port 2. Each closing unit is adapted to be able to open and close the passage of the feed channel 4.

[0036] When the material is normally air-selected, both closed units remain in an open state. At this time, an airflow can be formed in the feed channel 4 to entrain the material to rise, so that the material can complete the expected screening work at the feed gap 6. As the screening proceeds, more tobacco stems will gradually adhere to the bottom of the screen plate 5, which causes the passing force of the feed gap 6 to decrease, until the tobacco leaves are also pressed against the bottom of the screen plate 5 under the action of negative pressure. At this time, the upper closed unit 9 can be controlled to be in a closed state, which will cause the rising airflow to be cut off, the negative pressure in the feed channel 4 will be eliminated accordingly, and the abutment force of the material against the screen plate 5 will no longer exist, and then this part of the material will fall under the action of gravity. At the same time, the lower closed unit 10 in a closed state can receive this part of the material, especially to prevent the discharge of tobacco leaves from the discharge port 3.

[0037] After the two closed units are reopened, the upward airflow in the feed channel 4 is regenerated, and the material blocked by the lower closed unit 10 is suspended to varying degrees under the action of the airflow, that is, the tobacco leaves rise again, and the tobacco stems fall downward and are discharged. The screening plate 5 resumes its normal screening function.

[0038] In some examples, both closed units may include butterfly valves or gate valves (not shown). By controlling the brake, the expected opening and closing actions of the two closed units can be achieved. The butterfly valve and gate valve are both existing technologies, and their structures and principles are not described in detail in the present invention.

[0039] In other examples, a closed belt 11 is provided outside the feed channel 4, and the closed belt 11 extends into the feed channel 4 and is closed along the circumferential direction, so that the feed port 2 and the screen plate 5 are enclosed in the closed belt 11. In addition, an upper air port 12, a side material port 13 and a lower air port 14 are sequentially opened on the closed belt 11 along the circumferential direction, and the portion of the closed belt 11 located beside the upper air port 12 constitutes an upper closed unit 9, and the portion of the closed belt 11 located beside the lower air port 14 constitutes a lower closed unit 10.

[0040] It can be understood that when the upper air port 12 and the lower air port 14 are opposite to the inner cavity of the feed channel 4, an upward airflow can be formed in the feed channel 4, and the side port 13 will also be in a relative position with the feed port 2, so that the material can enter the feed channel 4 for screening and air selection. If the closing belt 11 is rotated so that the upper closing unit 9 and the lower closing unit 10 close the passage of the feed channel 4, the side port 13 will also be in an offset position with the feed port 2, so that the feed port 2 is closed instead of continuing to supply materials into the feed channel. Therefore, a driving mechanism 15 for driving the closing belt 11 to rotate is also provided on the outside of the feed channel 4 to realize the above-mentioned use process.

[0041] For example, the driving mechanism 15 may be a common pulley driving mechanism (not shown) driven by electricity or hydraulic pressure, and the rotation of the pulley drives the closing belt 11 to rotate as expected.

[0042] In a preferred example, a mounting frame 16 is also provided in the feed channel 4 so as to be elastic in the vertical direction, and the elasticity can be achieved by, for example, providing a spring 27 on the mounting frame 16. The above-mentioned screen plate 5 is fixedly provided in the mounting frame 16. When the bottom of the screen plate 5 is clogged with materials, the screen plate 5 will move upward under the action of negative pressure. In addition, a connecting rod 17 is provided on the side wall of the mounting frame 16, and a guide groove 18 is correspondingly provided through the side wall of the feed channel 4, and the connecting rod 17 is adapted in the guide groove 18 and extends out of the feed channel 4.

[0043] The driving mechanism 15 may include a driving wheel 19 that is rotatably arranged and coupled to the closing belt 11, and the driving wheel 19 is also configured with a tooth portion 20, and the end of the connecting rod 17 is also provided with a rack 21 that meshes with the tooth portion 20. When the screening plate 5 moves upward as described above, the synchronously moving rack 21 will drive the tooth portion 20 and the driving wheel 19 to rotate, thereby driving the closing belt 11 to rotate as expected, so that the airflow in the feed channel 4 is cut off, and the material adsorbed at the bottom of the screening plate 5 is automatically discharged.

[0044] In some embodiments, a mounting cavity 22 is provided in the sealing belt 11, especially in the lower sealing unit 10, and a through hole 23 connected to the mounting cavity 22 is provided on the inner wall of the sealing belt 11. In addition, a fan blade 24 is rotatably provided in the mounting cavity 22, a driving rod 25 is elastically provided beside the fan blade 24, and a transmission mechanism is adapted between the driving rod 25 and the rotating shaft of the fan blade 24. Under the transmission of the transmission mechanism, the axial movement of the driving rod 25 can be converted into a rotational force on the fan blade 24, for example, the transmission mechanism can be a gear rack 21 mechanism.

[0045] The driving rod 25 is also connected to a cable 26, and the end of the cable 26 away from the driving rod 25 is fixed to the upper closing unit 9. For ease of understanding, the operation process of a preferred example will be described exemplarily below:

[0046] 1. In the initial state, the mounting frame 16 is in a natural position and has the freedom to be pushed upward. The closing belt 11 is in an initial position where the upper air port 12 and the lower air port 14 are opposite to the inner cavity of the feed channel 4, and the side feed port 13 is opposite to the feed port 2. At this time, the material can be put into the feed channel 4 through the feed port 2. Under the influence of the rising airflow, the tobacco leaves pass through the screening plate 5 and the tobacco stems are intercepted;

[0047] 2. As the screening proceeds, more tobacco stems will be adsorbed on the bottom of the screening plate 5 under the action of negative pressure, until the tobacco leaves are also pressed against the bottom of the screening plate 5 under the action of negative pressure. Finally, the screening plate 5 will be pushed up under the action of pressure difference;

[0048] 3. The synchronously rising connecting rod 17 will drive the rack 21 and the toothed part 20 to transmit, and then the driving wheel 19 will drive the closing belt 11 to rotate until the two closing units close the passage of the feed channel 4 and the closing belt 11 closes the feed port 2. At this time, the material at the bottom of the screening plate 5 is no longer under pressure and falls to the top of the lower closing unit 10 under the action of gravity;

[0049] 4. During this period, the fan remains in operation, and eventually a pressure difference is formed on the upper and lower sides of the top of the sealing belt 11 (i.e., the upper sealing unit 9), thereby driving the top of the sealing belt 11 to sag upward. At this time, the cable 26 pulls the driving rod 25 to move axially, thereby driving the fan blades 24 to rotate. The rotating fan blades 24 can blow airflow to the materials falling from the bottom of the screening plate 5. The airflow can blow the materials to achieve preliminary separation of leaves and stems, and it is not easy for tobacco leaves to wrap tobacco stems.

[0050] 5. At the same time, the pressure difference on both sides of the screen plate 5 is eliminated, and the screen plate 5 will bounce back to the natural position, thereby driving the sealing belt 11 to rotate back to the initial position. Then, the upward airflow will be regenerated in the feed channel 4, and the material cut off by the lower sealing unit 10 will be selected by air.

[0051] In a preferred example, the spring 27 connected to the installation frame 16 can be selected as a damping spring, which will make the installation frame 16 not descend quickly, thereby providing sufficient operating time for the above steps 3, 4, and 5. For example, a closing piece can also be provided on the connecting rod 17 to cover the guide groove 18, or an elastic sealing member such as a bellows (not shown) can be provided in the guide groove 18 to cover the guide groove 18.

[0052] In addition, an installation channel connected to the upper closing unit 9 and the installation cavity 22 may be opened in the closing belt 11, and the above-mentioned cable 26 is arranged in the installation channel.

[0053] In a possible embodiment, the fan blades 24 may be replaced with stirring rods, and the installation cavity 22 may be constructed in the form of an open installation groove. The material falling from the bottom of the screening plate 5 will fall into the installation groove, and the material will be distributed by the rotating stirring rod. Among them, the closed belt 11 may specifically include a belt body and a mounting block connected to the belt body, and the above-mentioned installation cavity 22 and fan blades 24 may be set in the mounting block. Of course, the installation cavity 22 and fan blades 24 may also be provided with a setting space by thickening the belt body as a whole.

[0054] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A vacuum gravity sorting device for separating leaves and stems of plant leaves, comprising an air separation bin (1), the air separation bin (1) comprising a feed port (2) and at least two discharge ports (3), a vertically arranged feed channel (4) being constructed on the air separation bin (1), one of the discharge ports (3) being constructed at the bottom of the feed channel (4), and the feed port (2) being opened in the middle of the feed channel (4), wherein: A screening plate (5) is arranged in the feed channel (4), the screening plate (5) is located above the feed port (2), and a narrow and long material passing gap (6) is constructed on the screening plate (5), the material passing gap (6) is adapted to block stems but allow leaves to pass through in a bent manner; An upper sealing unit (9) is also provided in the feed channel (4), the upper sealing unit (9) is located above the sieve plate (5), and the upper sealing unit (9) is adapted to be able to open and close the passage of the feed channel (4); The upper closed unit (9) is in an open state to allow an ascending airflow to be formed in the feed channel (4) to carry the material upward; The upper sealing unit (9) is in a closed state to cut off the rising airflow, thereby eliminating the abutment force of the material against the sieve plate (5); A lower sealing unit (10) is also provided in the feed channel (4) below the feed port (2), and the lower sealing unit (10) is also adapted to be able to open and close the passage of the feed channel (4); A closed belt (11) is arranged outside the feed channel (4), the closed belt (11) extends into the feed channel (4) and is closed along the circumferential direction, and the feed port (2) and the sieve plate (5) are both located within the closed belt (11), an upper air port (12), a side air port (13) and a lower air port (14) are sequentially provided on the closed belt (11) along the circumferential direction, the portion of the closed belt (11) located beside the upper air port (12) constitutes the upper closed unit (9), and the portion of the closed belt (11) located beside the lower air port (14) constitutes the lower closed unit (10); A driving mechanism (15) for driving the closing belt (11) to rotate is also provided outside the feeding channel (4); A mounting frame (16) is vertically movable in the feed channel (4), the screening plate (5) is fixedly mounted in the mounting frame (16), a connecting rod (17) is arranged on the side wall of the mounting frame (16), a guide groove (18) is penetrated through the side wall of the feed channel (4), the connecting rod (17) extends out of the feed channel (4) from the guide groove (18), the driving mechanism (15) comprises a rotatably mounted driving wheel (19), the driving wheel (19) is coupled to the closing belt (11), a toothed portion (20) is also constructed on the driving wheel (19), a rack (21) is also arranged at the end of the connecting rod (17), and the rack (21) is meshed with the toothed portion (20).

2. The device for vacuum gravity separation of plant leaves, stems and mid-leaves according to claim 1 is characterized by: The screening plate (5) comprises two opposing plate bodies (7), and the material passing gap (6) is formed between the two plate bodies (7).

3. The vacuum gravity sorting device for plant leaves, stems and mid-leaves according to claim 2 is characterized by: A roller (8) is rotatably provided at the end of each plate body (7), and the material transfer gap (6) is formed between the two rollers (8).

4. The vacuum gravity sorting device for plant leaves, stems and mid-leaves according to claim 2 is characterized by: The two plates (7) are arranged to be inclined upward relative to each other, so that a material connection angle that expands toward the side of the feed port (2) is formed between the two plates (7).

5. The vacuum gravity sorting device for plant leaves, stems and mid-leaves according to claim 1 is characterized by: The upper closing unit (9) and the lower closing unit (10) may both comprise a butterfly valve or a gate valve.

6. The device for vacuum gravity separation of plant leaves, stems and mid-leaves according to claim 1, characterized in that: The closing belt (11) is provided with an installation cavity (22), the installation cavity (22) is located at the lower closing unit (10), the inner wall of the closing belt (11) is also provided with a through hole (23) connected to the installation cavity (22), a fan blade (24) is rotatably arranged in the installation cavity (22), a driving rod (25) is also elastically arranged in the installation cavity (22), a transmission mechanism is adapted between the driving rod (25) and the rotating shaft of the fan blade (24), a cable (26) is connected to the driving rod (25), and the end of the cable (26) away from the driving rod (25) is fixed to the upper closing unit (9); When the upper closing unit (9) closes the passage of the feed channel (4), the top of the closing belt (11) is recessed upward under the action of negative pressure, thereby pulling the cable (26) and causing the drive rod (25) to transmit power.

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