Fresh tea leaf screening method

Abstract

The invention belongs to the technical field of screening or screening in operation transportation, and particularly relates to a fresh tea leaf screening method which comprises the following steps: 1) removing impurities in fresh tea leaves to be screened; (2) conveying the to-be-screened fresh tea leaves subjected to impurity removal to a screening device; (3) carrying out nondestructive screening on the fresh tea leaves to be screened through a screening device, and classifying the fresh tea leaves into at least two types of fresh tea leaves with different specifications; and (4) selecting fresh tea leaves with different specifications from the classified fresh tea leaves. The method is implemented based on a fresh tea leaf screening production line, the fresh tea leaf screening production line comprises a vibration device, a conveying belt device, a screening device and an identification grabbing device, the vibration device is used for implementing impurity removal in the step 1), the conveying belt device is used for implementing conveying in the step 2), and the screening device is used for implementing lossless screening in the step 3). And the identifying and grabbing device is used for implementing selection in the step 4). According to the method, damage in the tea classification process can be reduced, and the quality of produced tea is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of screening or sieving in operation and transportation, and in particular relates to a fresh tea leaf screening method. Background Art

[0002] The fresh tea leaves picked manually or mechanically include various specifications such as one bud and one leaf, one bud and two leaves, one bud and three leaves, and one bud and four leaves. The types of fresh tea leaves mentioned in the fresh tea leaf identification technology disclosed in CN118447328A can be referred to.

[0003] After the fresh tea leaves are picked, they need to be classified by automatic screening equipment. In the prior art, there are screening machines disclosed in technical solutions such as CN206392410U and CN117139162A, which can screen fresh tea leaves of different sizes. However, in the screening process, a screen is used to screen fresh tea leaves of different sizes. The hard screen will inevitably cause or partially cause scratches and crushing injuries to the delicate fresh tea leaves during use, affecting the quality of the produced fresh tea leaves. In addition, the aforementioned CN206392410U is the most common screening machine. In its structure, the speed of directional transportation of screened tea leaves cannot be adjusted, and the efficiency cannot be improved. The amplitude of vibration driven by the vibrating motor to drive the screening device to vibrate cannot be adjusted. When it is necessary to increase the vibration amplitude, avoid clogging of the screen holes, and increase the directional transportation speed, it cannot be effectively achieved. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a method for screening fresh tea leaves, so as to avoid the problem that the current automatic tea screening equipment easily causes damage to the fresh tea leaves in the process of classifying tea leaves according to specifications, thereby achieving the effect of improving the quality of the output tea leaves.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The method for screening fresh tea leaves comprises the following steps:

[0007] 1) removing impurities from fresh tea leaves to be screened;

[0008] 2) conveying the fresh tea leaves to be screened after the impurities are removed to the screening device;

[0009] 3) classifying the fresh tea leaves to be screened by a screening device into at least two types of fresh tea leaves of different specifications;

[0010] The screening device comprises a tea accommodating bin with an open upper end; a horizontal leaf suction partition is fully provided in the middle of the tea accommodating bin for laying fresh tea leaves, and a plurality of densely distributed air suction holes are penetrated on the leaf suction partition; an air pressure sensor or a gas flow sensor is also provided in the tea accommodating bin below the leaf suction partition; an air suction pump is connected to the bottom wall of the tea accommodating bin, and the air suction pump is used to form a negative pressure inside the tea accommodating bin below the leaf suction partition; the air suction pump signal is connected to a controller for adjusting the operating power of the air suction pump, and the air pressure sensor or the gas flow sensor is connected to the controller signal; the tea accommodating bin is movably connected to a motion mechanism, and the motion mechanism is constructed to invert the tea accommodating bin from a positive state with its upper end open upward to an inverted state with its upper end open downward, and to make the tea accommodating bin in the inverted state stay at a first position and a second position respectively;

[0011] In step 2), the tea storage bin is placed in a forward state, and the fresh tea leaves to be screened are spread flat on the leaf suction partition;

[0012] Step 3) includes: 3.1) the controller controls the air suction pump to operate and form a negative pressure inside the tea storage bin below the leaf suction partition, thereby forming suction force on the fresh tea leaves laid on the leaf suction partition through the air suction holes;

[0013] 3.2) The movement mechanism inverts the tea storage bin from the forward state to the inverted state, and makes the tea storage bin stay in the first position;

[0014] 3.3) The controller controls to reduce the operating power of the suction pump, and the smaller tea leaves fall under the action of their own weight due to the reduced suction force;

[0015] 3.4) The movement mechanism moves the tea storage bin to the second position and stops there;

[0016] 3.5) The controller further controls to reduce the operating power of the suction pump or stops the operation of the suction pump, and the larger tea leaves fall under the action of their own weight due to the reduced suction force;

[0017] Thereby achieving the classification of fresh tea leaves of different specifications.

[0018] Furthermore, the method further comprises: step 4) selecting the fresh tea leaves of different specifications remaining in the classified fresh tea leaves;

[0019] The method is implemented based on a fresh tea leaf screening production line, which includes the screening device and further includes:

[0020] A vibration device for implementing the impurity removal in step 1);

[0021] A conveyor belt device, used to implement the conveying in step 2);

[0022] Identify the gripping device for carrying out the selection in step 4).

[0023] Furthermore, the vibration device includes a fixed support seat, and spring units are respectively provided at the four corners of the upper surface of the support seat, and the screening box is connected through four spring units, and the screening box is provided with an upper and lower screening plate, and the top of the screening box is connected with a vibrator; one of the spring units corresponds to each of the two sides of the front and rear ends of the screening box; the spring unit includes a bottom plate, and is connected to the support seat through the bottom plate, and a vertical spiral compression spring is provided on the upper surface of the bottom plate, and is connected to the top hinge seat directly above through the spiral compression spring, and a horizontal connecting hole is penetrated through the top hinge seat, and the connecting hole faces the side of the screening box; the two sides of the front end of the screening box are respectively protruding outwardly with a transverse rotating shaft and are rotatably inserted into the connecting hole of the corresponding top hinge seat on the outside, and the transverse rotating shafts on both sides are coaxial so that the screening box can be rotated by the transverse rotating shaft to adjust the inclination; the two sides of the rear end of the screening box are plugged into the connecting hole of the corresponding top hinge seat on the outside through a transverse plug-in shaft with adjustable position, so as to adapt to the rotation adjustment of the screening box;

[0024] The screening plate at the lower layer extends forward from the screening box body so as to be connected with the conveyor belt device.

[0025] Further, the conveyor belt device includes a horizontally extending outer fixed frame section, one end of the outer fixed frame section is telescopically connected to the inner telescopic frame section along the length direction of the outer fixed frame section, and the ends of the outer fixed frame section and the inner telescopic frame section that are far away from each other are respectively provided with conveying rollers for installing the conveyor belt, and a tensioning and holding unit is connected below the outer fixed frame section; the tensioning and holding unit includes two steering rollers arranged at intervals along the length direction of the outer fixed frame section, the two steering rollers are rotatably connected to the bottom of the outer fixed frame section, and the axial direction is parallel to the axial direction of the conveying roller, and three lifting rollers are also arranged at intervals between the two steering rollers, and the axial directions of the three lifting rollers are parallel to the axial direction of the conveying roller and are all lifted and connected to the bottom of the outer fixed frame section; a conveyor belt is connected between the two conveying rollers, and the lower conveyor belt section between the two conveying rollers is S-shaped and passes around each steering roller and lifting roller in turn; when the inner telescopic frame section is retracted, the middle lifting roller rises accordingly, and the two outer lifting rollers fall synchronously; when the inner telescopic frame section is extended, the middle lifting roller falls accordingly, and the two outer lifting rollers rise synchronously, so as to keep the conveyor belt always in a tensioned state;

[0026] The end of the lower screening plate extending out of the screening box is located directly above the outer fixed frame section; the inner telescopic frame section faces the screening device.

[0027] Furthermore, the movement mechanism comprises an oval-shaped circular track, two straight sections of the oval-shaped circular track are horizontally arranged and respectively located at the upper and lower sides in the vertical direction, the tea storage bin is slidably connected to the circular track, and during the sliding process of the tea storage bin along the circular track, its upper end opening is always facing the inner side of the circular track, and when the tea storage bin slides along the circular track to the upper straight section, the first position and the second position can be formed respectively; storage mechanisms are respectively arranged below the first position and the second position, and the storage mechanisms comprise a transmission belt, the transmission belt passes through the inner side of the circular track, and the end of the transmission belt away from the conveyor belt device extends out of the circular track and a storage box is arranged below;

[0028] The inner telescopic frame section extends into the inner side of the annular track when extended, and is vertically located between the tea accommodating bin in the forward state and the transmission belt.

[0029] Furthermore, the tea storage bin is in a rectangular shape, and a plurality of air pressure sensors or gas flow sensors are provided inside the tea storage bin, which are respectively connected to both sides of the tea storage bin and are arranged at intervals along its length direction; there are multiple air pumps, which are arranged at intervals along the length direction of the tea storage bin.

[0030] Furthermore, the identification and grasping device includes a camera recognition unit for photographing and identifying fresh tea leaves on the conveyor belt. The camera recognition unit signal is connected to a mechanical gripper unit. The mechanical gripper unit is used to grasp fresh tea leaves of different specifications according to the recognition results of the camera recognition unit. The camera recognition unit and the mechanical gripper unit are spaced apart along the conveying direction of the transmission belt and are located just above one end of the transmission belt extending out of the circular track.

[0031] Furthermore, a spreading unit is provided on one side of the camera recognition unit away from the mechanical gripper unit, for spreading the fresh tea leaves on the conveyor belt evenly for identification;

[0032] A collecting mechanism is arranged on the outer side of the transmission belt, and the mechanical gripper unit is constructed to move back and forth above the transmission belt and the collecting mechanism so as to move the grabbed fresh tea leaves to the collecting mechanism.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The screening method of the present invention, in the process of classifying large and small fresh tea leaves, utilizes the difference in suction force on large and small fresh tea leaves of different specifications, and adjusts the operating power of the suction pump at the first position and the second position, so that the fresh tea leaves of different sizes fall at different positions, thereby achieving screening. The disadvantages of using a hard screen for screening are avoided, the scratch damage to the fresh tea leaves caused by the screening process is effectively reduced, and the quality of tea leaves is improved.

[0035] 2. The vibration device of the present invention can adjust the inclination of the screening box so that the screening plate can be tilted toward the direction of discharging, and the discharging end can be lower. Under the same vibration conditions, the discharging speed is faster and the efficiency is higher. The amplitude of the vibrator can also be adjusted. When necessary, the vibration amplitude can be increased to avoid clogging of the screen holes, thereby further improving the speed of directional transportation of fresh tea leaves.

[0036] 3. In the conveyor belt device of the present invention, when the inner telescopic frame section retracts, the middle lifting roller rises accordingly, and the two outer lifting rollers descend synchronously; when the inner telescopic frame section extends, the middle lifting roller descends accordingly, and the two outer lifting rollers rise synchronously, so as to keep the conveyor belt in a tensioned state at all times; the response stroke of each lifting roller is short and the response is timely. Combined with the control of the controller, the speed of the inner telescopic frame section when retracting can be increased accordingly, while keeping the conveyor belt tensioned but not loose, so as to effectively realize the dropping and laying of fresh tea leaves. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A three-dimensional diagram of the fresh tea leaf screening production line of the embodiment;

[0038] Figure 2 for Figure 1 Side view of the fresh tea leaf screening production line;

[0039] Figure 3 for Figure 2 A top view of

[0040] Figure 4 A schematic diagram of a structural form of a vibration device in an embodiment;

[0041] Figure 5 for Figure 4 A three-dimensional schematic diagram of a single screening box;

[0042] Figure 6 It is a three-dimensional schematic diagram of a spring unit alone in the vibration device of the embodiment;

[0043] Figure 7 A schematic diagram of another structural form of the vibration device in the embodiment;

[0044] Figure 8 for Figure 7 A partial schematic diagram of the rear end of the screening box;

[0045] Fig. 9 for Figure 7 A partial schematic diagram of the vibrator on the top of the middle screening box;

[0046] Fig.10 for Fig. 9 A three-dimensional schematic diagram showing the motor and the centrifugal block separately;

[0047] Fig.11 is a three-dimensional diagram of a conveyor belt device in an embodiment;

[0048] Fig.12 for Fig.11 A three-dimensional view of the conveyor belt device from another perspective;

[0049] Fig.13 A schematic diagram of the conveyor belt device in the embodiment in an extended state;

[0050] Fig.14 A schematic diagram of a retracted state of a conveyor belt device according to an embodiment;

[0051] Fig.15 It is a separate three-dimensional diagram of the tea storage bin in the embodiment;

[0052] Fig.16 is a schematic structural diagram of a screening device in an embodiment;

[0053] Fig.17 for Fig.16 A schematic cross-sectional view of the tea storage bin at the middle AA section;

[0054] Fig.18 A three-dimensional diagram of a screening device according to an embodiment;

[0055] Fig.19 A three-dimensional diagram of some components of the grasping device in the embodiment;

[0056] Fig. 20 for Fig.19 The part of the grasping device identified in the figure constitutes a stereogram from another perspective;

[0057] Among them, a vibration device 100, a conveyor belt device 200, a screening device 300, an identification and grasping device 400, a support seat 1, a spring unit 2, a bottom plate 3, a spiral compression spring 4, a top hinge seat 5, a connecting hole 6, a screening box 7, an upper screening plate 8, an upper discharge port 9, a miscellaneous branch collection box 10, a lower screening plate 11, a residue collection box 12, a horizontal rotating shaft 13, a horizontal plug shaft 14, a positioning hole 15, a groove 16, a vertical slider 17, a dovetail guide rail 18, a dovetail groove 19, a vibrator 20, a motor 21, an output shaft 22, a centrifugal block 23, a counterweight 24, a fan-shaped portion 25, a connecting screw hole 26, a through hole 27, a screw 28, a screw rod 29, a conveyor belt 30, an external fixed frame section 31, and an internal telescopic frame section 32. Conveying roller 33, tensioning and holding unit 34, steering roller 35, lifting roller 36, servo drive motor 37, give way slot 38, driving gear 39, rack 40, retaining frame 41, side wing plate 42, telescopic mechanism 43, U-shaped bracket 44, tea accommodating bin 50, leaf suction partition 51, suction hole 52, air pressure sensor 53, suction pump 54, driving wheel 55, circular track 56, slide rail 57, straight section 58, first position 59, second position 60, guide rail groove 61, storage mechanism 62, first conveyor belt 63, first storage box 64, second conveyor belt 65, second storage box 66, guide plate 67, spreading unit 70, camera recognition unit 71, mechanical gripper unit 72, collecting mechanism 73. DETAILED DESCRIPTION

[0058] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0059] The fresh tea leaf screening method of a specific embodiment comprises the following steps:

[0060] 1) Removing impurities from the fresh tea leaves to be screened; impurities here mainly refer to some unnecessary large debris, branches, and small broken pieces and residues in the picked fresh tea leaves;

[0061] 2) conveying the fresh tea leaves to be screened after the impurities are removed to the screening device;

[0062] 3) Screening the fresh tea leaves to be screened by a screening device, and classifying them into at least two types of fresh tea leaves with different specifications; the present embodiment is illustrated and described as being divided into two types of smaller specifications and larger specifications;

[0063] 4) Selecting out the tea leaves of different specifications that remain in the classified tea leaves due to incomplete classification.

[0064] Among them, steps 1), 2) and 4) can be implemented manually. The screening device is the core innovation of this technical solution, please refer to Figure 15-18The screening device includes a tea accommodating bin 50 with an open top; a horizontal leaf suction partition 51 is fully paved in the middle of the tea accommodating bin 50 for laying fresh tea leaves, that is, the leaf suction partition 51 is connected to the inner side of the corresponding side wall of the tea accommodating bin 50 on all sides without leaving any gaps, and a plurality of densely distributed air suction holes 52 are formed on the leaf suction partition 51, and the air suction holes 52 are circular. The dense distribution specifically means that the diameter of the air suction holes 52 is such that fresh tea leaves cannot pass through, and they are only used for ventilation. In order to ensure the suction force and the effective area, as many air suction holes 52 as possible are formed on the leaf suction partition 51; below the leaf suction partition 51, an air pressure sensor is also provided in the tea accommodating bin 50 The bottom wall of the tea storage bin 50 is connected with an air suction pump 54, whose air suction port faces the inside of the tea storage bin 50 and the air exhaust port faces the outside. The air suction pump 54 can continuously form a negative pressure inside the tea storage bin 50 below the leaf suction partition 51, thereby forming suction on the fresh tea leaves laid on the leaf suction partition 51 through the air suction hole 52 (intake); the air suction pump 54 signal is connected to a controller for adjusting the operating power of the air suction pump 54 (not shown in the figure, the controller can also perform logical control on other electronic devices at the same time), and the air pressure sensor 53 is connected to the controller signal so that the controller can adjust the operating power of the air suction pump 54 according to the measured air pressure value.

[0065] The tea accommodating bin 50 is movably connected to a moving mechanism, and the moving mechanism is configured to invert the tea accommodating bin 50 from a normal state with its upper end opening upward to an inverted state with its upper end opening downward, and to make the tea accommodating bin 50 in the inverted state stay at a first position 59 and a second position 60. The first position 59 and the second position 60 are different positions for fresh tea leaves to fall, and of course, the moving mechanism can also restore the tea accommodating bin 50 to the initial position of the normal state.

[0066] When used for screening, in step 2), the tea accommodating bin 50 should first be in a forward state, and the fresh tea leaves to be screened should be evenly spread on the leaf suction partition 51, and spread as much as possible in a full layer to cover all the suction holes 52.

[0067] Step 3) specifically includes: 3.1) the controller controls the air suction pump 54 to operate and form a negative pressure inside the tea storage bin 50 below the leaf suction partition 51, thereby forming suction on the fresh tea leaves laid on the leaf suction partition 51 through the air suction hole 52; the air pressure sensor 53 detects the air pressure value, and adjusts the operating power of the air suction pump 54 through the controller to maintain the required suction force stable, and controls the air suction pump 54 to ensure that the fresh tea leaves will not fall when the tea storage bin 50 is in an inverted state, so as to avoid the fresh tea leaves falling during the process of the tea storage bin 50 being inverted from the forward state to the inverted state, and before the inverted state reaches the designed position.

[0068] 3.2) The movement mechanism inverts the tea accommodating bin 50 from the forward state to the inverted state, and makes the tea accommodating bin 50 stay at the first position 59 first.

[0069] 3.3) The controller reduces the operating power of the air pump 54, and adjusts it in combination with the measured air pressure value to maintain the stability of the operating power, or adjusts the operating power in real time in combination with the measured air pressure value to maintain the stability of the required suction force (the former can better protect the air pump, and the latter can make the required suction force more accurate). The smaller tea leaves fall under the action of their own weight due to the reduced suction force.

[0070] 3.4) The motion mechanism drives the tea storage bin 50 to move to the second position 60 and stay there.

[0071] 3.5) The controller further reduces the operating power of the air suction pump 54, and adjusts the operating power in combination with the measured air pressure value to maintain the stability of the operating power, or adjusts the operating power in real time in combination with the measured air pressure value to maintain the stability of the required suction force. The larger tea leaves fall under the action of their own weight due to the reduced suction force. In this step, if only two categories are divided, the operation of the air suction pump can also be stopped.

[0072] In this way, the smaller tea leaves and the larger tea leaves can be distinguished.

[0073] The aforementioned tea leaves with smaller specifications refer to tea leaves with one bud and one leaf, one bud and two leaves, and the tea leaves with larger specifications refer to tea leaves with one bud and three leaves, one bud and four leaves. Smaller tea leaves have fewer, smaller leaves and a higher curl, and have a smaller contact area on the leaf suction partition 51, a smaller area covering the air suction hole 52, and a smaller suction force. Larger tea leaves have a larger contact area on the leaf suction partition 51, a larger area covering the air suction hole 52, and a larger suction force. Although the weight of larger tea leaves is relatively larger, the weight of the tea leaves themselves is very light. During the process of reducing the operating power of the air pump 54, the change in the suction force determines the order of falling, which is the key parameter of the falling order, so the aforementioned device and method can be used for screening. The specific operating power values ​​of the air pump 54 at each stage in the process are obtained by actual measurement through a certain sample size test in the early stage, mapped with the air pressure value and the suction force, and then preset in the controller for corresponding control and adjustment. Parameters can be adjusted and modified when necessary.

[0074] During implementation, the controller and the power supply for each electronic device can be set on the tea storage bin 50; the controller can also be set in the control room, and connected to the pressure sensor 53 and the suction pump 54 signal by wireless transmission. The motion mechanism can realize the relevant actions, which is not limited to the specific ones. It can be a mechanical arm connected to the tea storage bin 50, which has three degrees of freedom and a turntable drive. Storage mechanisms 62, such as collection boxes, are respectively provided below the first position 59 and the second position 60 to classify and collect the smaller fresh tea leaves and larger fresh tea leaves that fall, and then the selection in step 4) can be carried out. If it is necessary to classify the fresh tea leaves more finely, the motion mechanism can be added to drive the different positions where the inverted tea storage bin 50 stays, which are not limited to the first position 59 and the second position 60. Combined with the control of the operating power of the suction pump 54 by the controller, more detailed classification can be achieved, and a variety of fresh tea leaves of different specifications can be classified.

[0075] Please refer to Fig.16 and Fig.18 The movement mechanism includes an annular track 56 in the shape of an oval circle, and two straight sections 58 of the annular track 56 in the shape of an oval circle are arranged horizontally and respectively located at the upper and lower sides in the vertical direction. The tea storage bin 50 is slidably connected to the annular track 56. During the sliding process of the tea storage bin 50 along the annular track 56, its upper end opening is always facing the inner side of the annular track 56, so as to form a positive state on the lower straight section 58 and an inverted state on the upper straight section 58. When the tea storage bin 50 slides along the annular track 56 to the upper straight section 58, it can stay at different positions respectively and form the first position 59 and the second position 60 correspondingly. It can be understood that the straight section 58 of the annular track 56 has a certain length, which can provide the tea storage bin 50 with a first position 59 and a second position 60 to stay respectively.

[0076] During implementation, the inner side of the annular track 56 may be provided with a chain or belt type circulation mechanism, connected to the tea accommodating bin 50, driving it to slide in a circumferential circulation.

[0077] In this embodiment, the storage mechanism 62 includes a transmission belt, which passes through the inner side of the annular track 56, and a storage box is provided below the end of the transmission belt. The transmission belt below the first position 59 is a first transmission belt 63, and the corresponding storage box is a first storage box 64. The transmission belt below the second position 60 is a second transmission belt 65, and the corresponding storage box is a second storage box 66.

[0078] Please refer to Fig.15 , Fig.18In this embodiment, the tea accommodating bin 50 is in a rectangular shape, and its two ends are respectively connected with connecting shafts extending along its length direction and connected to driving wheels 55 through the connecting shafts, specifically two sets of connecting shafts and driving wheels 55 spaced apart in the width direction. The annular track 56 includes two parallel and opposite slide rails 57, and the opposite surfaces of the two slide rails 57 are provided with oblong guide grooves 61. The tea accommodating bin 50 is located between the two slide rails 57, and the driving wheels 55 at both ends are rollingly connected in the corresponding guide grooves 61. The driving wheel 55 is equipped with a driving motor (not shown in the figure), which is connected by a wireless signal control of the controller. Different track segments are adapted to control the corresponding rotation directions of the driving wheel 55, driving the tea storage bin 50 to move in a circumferential cycle along the guide groove 61; when the arc segment at one end of the guide groove 61 rises, it can appropriately use the inertia of the lower straight segment 58 when moving. If necessary, it can also assist the lifting machinery (not shown in the figure) installed nearby to help the tea storage bin 50 rise from the forward state through the arc segment of the guide groove 61 to the inverted state; after the tea leaves are classified, the arc segment at the other end of the guide groove 61 is driven downward or slides with the help of its own weight, and the inverted state returns to the forward state.

[0079] With respect to the arrangement of two parallel and opposite slide rails 57, as another alternative driving scheme, a circulating chain rail plate type circulation machine can be respectively arranged on the opposite inner side surfaces, and the ends of the tea storage bin 50 in the length direction are respectively fixedly connected to the corresponding chain rail plates by two extended connecting shafts, and the chain rail plate type circulation machine drives the circumferential circulation movement thereof, so that a more uniform movement can be achieved and the movement stability can be improved.

[0080] The circumferential circular movement method can take one circle of movement as one working step in each classification process, and the movement trajectory is regular, which is convenient for counting and operation implementation.

[0081] Please see again Fig.15 and Fig.17 In order to control the suction force of each area on the leaf suction partition 51 more accurately, a plurality of air pressure sensors 53 are provided in the tea storage bin 50, which are respectively connected to both sides of the tea storage bin 50 and arranged at intervals along the length direction thereof; the number of air suction pumps 54 is also multiple, centered, and arranged at intervals along the length direction of the tea storage bin 50. When the suction force is uneven or the local suction force is insufficient, the power of the adjacent air suction pump 54 can be correspondingly controlled to increase to ensure the use effect.

[0082] Please see again Fig.18, guide plates 67 extending upward and outward are provided on both sides of the roller frame where the transmission belt is located, and the length of the guide plate 67 corresponds to or is greater than the distance between the two slide rails 57; the lower edge of the guide plate 67 extends to above the side edge of the transmission belt. In this way, it is possible to avoid the fallen fresh tea leaves from falling on the outside of the transmission belt as much as possible, and ensure that the classified tea leaves eventually fall into the storage box. During implementation, the roller frame where the transmission belt is located, the slide rail 57, the storage box and other components that need to be fixed are all fixedly arranged and connected to a fixed ground or a fixed equipment frame. They are conventional fixed connections and are not shown in the accompanying drawings. The transmission belt, the roller frame where it is located, the fixed connection, the guide plate 67, etc. do not interfere with the circumferential circulation movement of the tea storage bin 50.

[0083] During implementation, the air pressure sensor 53 in the tea storage bin 50 may also use a gas flow sensor (not shown in the figure). During feedback control, the gas flow sensor can detect the pressure and flow in the space below the leaf suction baffle 51 in the tea storage bin 50. Combined with the air pressure value and instantaneous flow, it can better reflect the coverage of the fresh tea leaves on the suction holes 52 and the gas parameters in the space below the leaf suction baffle 51 in the tea storage bin 50. The controller can control and adjust the operating power of the suction pump 54 based on the feedback of the gas flow sensor on the two parameters of pressure and flow, which has a higher accuracy in achieving the use effect, but the control programming logic is relatively more complicated and the cost is higher.

[0084] To optimize the technical solution and improve the degree of automation, please refer to Figure 1-Figure 3 This embodiment provides a fresh tea leaf screening production line, which includes the above-mentioned screening device 300, and also includes:

[0085] A vibration device 100, used to implement the impurity removal in step 1);

[0086] A conveyor belt device 200, used to implement the conveying in step 2);

[0087] The identification and grasping device 400 is used to implement the selection in step 4).

[0088] See also Figure 4-Figure 6The vibration device 100 includes a fixed support base 1, and spring units 2 are respectively arranged at the four corners of the upper surface of the support base 1, and a screening box 7 is connected through four spring units 2. The screening box 7 has two layers of screening plates, and the top of the screening box 7 is connected with a vibrator 20 for directional movement of unscreened fresh tea leaves during vibration; the two sides of the front and rear ends of the screening box 7 correspond to one spring unit 2 respectively; the spring unit 2 includes a bottom plate 3, and is connected to the support base 1 through the bottom plate 3, and the upper surface of the bottom plate 3 is provided with a vertical spiral compression spring 4, and through the spiral compression spring 4 is connected to the top hinge seat 5 just above, and a horizontal connection hole 6 is penetrated through the top hinge seat 5, and the connection hole 6 faces the side of the screening box 7; the two sides of the front end of the screening box 7 are respectively protruded outwards with a transverse rotating shaft 13 and are rotatably inserted into the connection hole 6 of the corresponding top hinge seat 5 on the outside, and the transverse rotating shafts 13 on both sides are coaxial so that the screening box 7 can be rotated to adjust the inclination of the transverse rotating shaft 13; the two sides of the rear end of the screening box 7 are plugged into the connection hole 6 of the corresponding top hinge seat 5 on the outside through the transverse plug-in shaft 14 with adjustable position, so as to adapt to the rotation adjustment of the screening box 7.

[0089] When the vibrator 20 vibrates, the direction in which the unscreened material moves corresponds to the front-rear direction of the screening box 7. By adjusting the inclination of the screening box 7, the screening plate can be tilted toward the discharging direction, and the discharging end is lower. Under the same vibration conditions, the discharging speed is faster and the efficiency is higher.

[0090] exist Figure 4 and Figure 5 In the embodiment, the position of the transverse plug shaft 14 is specifically adjusted in the following manner: a plurality of positioning holes 15 are provided on the side surface of the rear end of the screening box 7, and the plurality of positioning holes 15 are arranged at intervals on an arc line with the transverse rotating shaft 13 as the rotating axis; on one side, the transverse plug shaft 14 passes through the connecting hole 6 and any one of the positioning holes 15.

[0091] In this mode, the transverse plug shaft 14 is an independent plug-in component, which can be selectively plugged into any positioning hole 15; when in use, first pull out the transverse plug shaft 14, lift and move the rear end of the screening box 7, and the screening box 7 rotates with the transverse rotating shaft 13 at the front end as the rotation axis, adjust its front-to-back inclination, select the required positioning hole 15 to be coaxial with the connecting hole 6, and then pass the transverse plug shaft 14 through the connecting hole 6 and the positioning hole 15 to achieve the adjusted fixation. After fixation, it can be used with vibration. If it is necessary to prevent the shaft from falling out of the hole, an anti-falling transverse pin (not shown in the figure) can be set at the part of the shaft end exposed from the hole.

[0092] In order to simplify the structure and facilitate use, the positioning holes 15 on both sides of the rear end of the screening box 7 are all set through and symmetrical on both sides, and a horizontal insertion shaft 14 passes through the connection holes 6 of the top hinge seats 5 on both sides of the rear end of the screening box 7, and any group of symmetrical positioning holes 15 in the middle. In this way, after each adjustment, only one horizontal insertion shaft 14 needs to be inserted horizontally, and it is not necessary to insert them on both sides of the rear end, which is more convenient and reliable to operate.

[0093] In addition, Figure 7 and Figure 8 In the embodiment, the position of the transverse plug-in shaft 14 is adjustable as follows: a vertical screw rod 29 is rotatably provided on the side surface of the rear end of the screening box 7, and a vertical slider 17 is threadedly connected to the screw rod 29 to form a screw transmission structure. The screw rod 29 is rotated to produce a relative vertical movement with the vertical slider 17. The transverse plug-in shaft 14 is connected to the outer side of the vertical slider 17 and is rotatably inserted into the connecting hole 6 of the outer side corresponding to the top hinge seat 5; the two spring units 2 that are rotatably inserted into the transverse plug-in shaft 14 are slidably connected to the support seat 1 in the front and rear directions of the screening box 7.

[0094] In this way, as the screw rod 29 is operated to rotate forward or reverse, corresponding to the rising or falling action (swing) of the rear end of the screening box 7, the screw rod 29 is synchronized, the vertical height of the vertical slider 17 remains unchanged, but it rotates at a certain angle, and the horizontal plug shaft 14 rotates accordingly in the connecting hole 6 of the top hinge seat 5 on its outer side. At the same time, in order to adapt to the swing of the rear end of the screening box 7, the horizontal position of the vertical slider 17 changes, and the two spring units 2 at the rear end slide accordingly in the front and rear upward of the screening box 7.

[0095] Specifically, the lower surface of the bottom plate 3 of the two spring units 2 that are rotatably plugged into the transverse plug shaft 14 is provided with a dovetail guide rail 18, and the upper surface of the support seat 1 is provided with a dovetail groove 19 extending in the front and rear directions along the screening box 7. The bottom plate 3 is slidably connected in the dovetail groove 19 through the dovetail guide rail 18. The two spring units 2 at the front end are still fixedly connected to the support seat 1 through the bottom plate 3 (without the dovetail guide rail). There is a vertical groove 16 on the side surface of the rear end of the screening box 7, and the screw rod 29 is located in the groove 16. The upper and lower ends are rotatably connected to the wall of the groove 16. The upper end passes through the groove 16 and has a head with an inner hexagon for easy adjustment. The vertical slider 17 is in the groove 16, and the two sides are limited. The screw rod 29 rotates and the vertical slider 17 slides relative to the groove 16.

[0096] During implementation, the screw rod 29 can be directly screwed with a hexagonal wrench, and the two spring units 2 at the rear end slide adaptively in the dovetail groove 19 through the dovetail guide rail 18. It is also possible that the hexagonal wrench does not slide adaptively when it is screwed for adjustment (due to friction), but the elastic deformation of each spiral compression spring 4 is used to temporarily support the adjustment action. With the vibration during work, the two spring units 2 at the rear end slide adaptively into place to release the stiffness of the spiral compression spring 4. If the screw rod 29 needs to be fixed after adjustment, a locking screw that penetrates through the head with an inner hexagonal screw can be vertically threaded and screwed into the head to tighten the screening box 7 to prevent the screw rod 29 from rotating.

[0097] Please continue to see Figure 7 , Fig. 9 and Fig.10 The vibrator 20 includes a motor 21, and an output shaft 22 of the motor 21 is sleeved with adjacent centrifugal blocks 23 and counterweight blocks 24. The centrifugal blocks 23 are sleeved on the output shaft 22 in synchronous rotation, and the counterweight blocks 24 are sleeved on the output shaft 22 in rotation. The centrifugal blocks 23 have an eccentric sector 25, and the sector 25 is provided with a plurality of circumferentially spaced connecting screw holes 26. The cross-sectional shape of the counterweight block 24 corresponds to that of the centrifugal blocks 23. A through hole 27 is provided on the counterweight block 24, and a screw 28 passes through the through hole 27 and is threadedly connected to any connecting screw hole 26, thereby relatively fixing the centrifugal blocks 23 and the counterweight blocks 24. As the counterweight block 24 rotates relative to the output shaft 22, the screw 28 is selectively threadedly connected to the connecting screw hole 26, and the overlap between the centrifugal blocks 23 and the counterweight blocks 24 is changed, so that the amplitude can be adjusted. The higher the overlap, the greater the amplitude. In order to facilitate rotation adjustment and connection and fixation in both directions, through holes 27 are respectively opened at both ends of the arc position of the counterweight block 24.

[0098] In this way, the amplitude adjustment of the vibrator 20 is conveniently realized. When necessary, the vibration amplitude can be increased to avoid clogging of the sieve holes and further increase the speed of directional transportation.

[0099] Please continue to see Figure 7The screening box 7 is equipped with an upper screening plate 8 and a lower screening plate 11, both of which extend out of the screening box 7 from the front end, and the lower screening plate 11 extends longer so as to be connected to the conveyor belt device 200. In order to avoid over-dense screening and damaging the fresh tea leaves, when implementing step 1), the picked fresh tea leaves containing impurities to be screened are poured into the screening box 7 from the feeding port provided at the top rear end, and the vibrator 20 drives the screening box 7. The upper screening plate 8 has large sieve holes, and only large impurities, branches, etc. are screened out. Both larger and smaller fresh tea leaves pass through the sieve holes of the upper screening plate 8 and fall onto the lower screening plate 11, and the probability of being scratched and squeezed is low. The lower screening plate 11 has small sieve holes, and only broken dregs pass through and fall into the residue collection box below. 12. The vibrator 20 drives the screening box 7 to vibrate, so that the objects on the screening plate move to the front end of the screening box 7. The debris, branches, etc. on the upper screening plate 8 are guided to one side through the upper discharge port 9 with an inclined plate and fall into the miscellaneous branch collection box 10. The large and small fresh tea leaves on the lower screening plate 11 move to the front end of the screening box 7, and fall after reaching the protruding end of the lower screening plate 11. The conveyor belt device 200 of the subsequent process receives them and transports them to the screening device 300 for separation of larger and smaller fresh tea leaves without screening damage.

[0100] See also Figure 11-Figure 14 The conveyor belt device 200 includes an outer fixed frame section 31 extending in the horizontal conveying direction. Along the length direction of the outer fixed frame section 31, one end of the outer fixed frame section 31 is telescopically connected to the inner telescopic frame section 32. The ends of the outer fixed frame section 31 and the inner telescopic frame section 32 that are away from each other are respectively provided with conveying rollers 33 with a driving source for installing the conveyor belt 30. A tensioning and holding unit 34 is connected below the outer fixed frame section 31; the tensioning and holding unit 34 includes two steering rollers 35 arranged at intervals along the length direction of the outer fixed frame section 31. The two steering rollers 35 are rotatably connected to the bottom of the outer fixed frame section 31, and the axial direction is parallel to the axial direction of the conveying roller 33. Three lifting rollers 36 are also arranged between the two steering rollers 35. The axial directions of the three lifting rollers 36 are parallel to the axial direction of the conveying roller 33 and are all lifted and connected below the outer fixed frame section 31; a closed-loop conveyor belt 30 is connected between the two conveying rollers 33, and the conveyor belt section at the lower part between the two conveying rollers 33 is S-shaped and passes around each steering roller 35 and lifting roller 36 in turn. Specifically, the conveyor belt 30 is horizontally connected to two conveyor rollers 33, passes around the conveyor roller 33 and then extends horizontally in reverse from the bottom to the steering roller 35, passes over the steering roller 35 and then extends downward, passes over three lifting rollers 36 in an S shape and then extends upward, passes over the other steering roller 35 and then extends horizontally to the steering roller 35 at the other end, forming a closed loop.

[0101] See also Fig.13 and Fig.14When the inner telescopic frame section 32 retracts, the middle lifting roller 36 rises accordingly, and the two outer lifting rollers 36 fall synchronously; when the inner telescopic frame section 32 extends, the middle lifting roller 36 falls accordingly, and the two outer lifting rollers 36 rise synchronously, keeping the conveyor belt 30 always in a tensioned state; the response stroke of each lifting roller 36 is shorter and the response is more timely. Combined with the control of the controller, the speed of the inner telescopic frame section 32 when retracting can be increased accordingly. Overall, the space occupied and the space change are also smaller, and it is safe and reliable to use. During implementation, the telescopic movement of the inner telescopic frame section 32 relative to the outer fixed frame section 31 and the lifting movement of the lifting roller 36 can be achieved by a pneumatic telescopic cylinder, an electric telescopic cylinder or a hydraulic telescopic cylinder, or by other mechanical drive mechanisms. There is no specific limitation, as long as it can be effectively and timely controlled in combination with the controller.

[0102] Please continue to see Fig.12 and Fig.13 Each conveying roller 33, the steering roller 35 and the two lifting rollers 36 adjacent to the two steering rollers 35 are respectively connected to an independent servo drive motor 37. In this way, combined with the control of the controller, the effective transportation of the conveyor belt 30 can be better guaranteed, and the conveyor belt 30 can always be transported forward during the extension and retraction process of the inner telescopic frame section 32. Specifically, the servo drive motor 37 is fixed on the corresponding frame section to transmit torque to the corresponding roller.

[0103] Please continue to see Fig.11 One end of the outer fixed frame segment 31 facing the inner telescopic frame segment 32 is recessed to form a accommodating cavity, and one end of the inner telescopic frame segment 32 facing the outer fixed frame segment 31 is connected to the accommodating cavity in a socket-type sliding manner. The two side walls of the accommodating cavity are penetrated by a clearance groove 38 extending along the length direction of the outer fixed frame segment 31. The inner end of the inner telescopic frame segment 32 is provided with a driving motor, and the driving motor drives the connected output shaft (not shown in the figure). The output shaft is rotatably connected to the inner end of the inner telescopic frame segment 32, and both ends of the output shaft extend out of the clearance groove 38 and are connected to the driving gear 39. The driving gear 39 is meshed and connected with the rack 40 extending along the length direction of the outer side of the outer fixed frame segment 31.

[0104] Please continue to see Fig.11 , Fig.12The tension holding unit 34 also includes a holding frame 41, which includes two side wing plates 42 that are spaced apart and parallel to each other in the width direction of the outer fixed frame segment 31, and the two side wing plates 42 are fixedly connected to the lower surface of the outer fixed frame segment 31. The steering roller 35 is rotatably connected between the two side wing plates 42 and is respectively located at the front end and the rear end of the two side wing plates 42. The two lifting rollers 36 adjacent to the two steering rollers 35 are connected to the bottom of the two side wing plates 42 through a telescopic mechanism. The middle lifting roller 36 is rotatably connected to a U-shaped bracket 44. The two free ends of the U-shaped bracket 44 are respectively connected to the two side wing plates 42, and the middle lifting roller 36 can be vertically moved and connected between the two free ends of the U-shaped bracket 44.

[0105] Specifically, the telescopic mechanism of the two lifting rollers 36 adjacent to the two steering rollers 35 can be driven and lifted by adopting the same structural form as the outer fixed frame section 31 and the inner telescopic frame section 32; the middle lifting roller 36 can be a roller sleeved on the outside of the roller shaft, and a driving motor is arranged inside the roller shaft. The driving end of the driving motor extends out of the vertical groove of the U-shaped bracket 44 and is connected to the driving gear, and the driving gear is meshed and connected with the vertical rack on the outside of the U-shaped bracket 44. The middle lifting roller 36 is idle because it has no power source, and can also be replaced by another connection scheme, such as using a pneumatic telescopic cylinder connected between the two side wing plates 42, the telescopic end of the pneumatic telescopic cylinder is downward and connected to the "┌┐"-shaped bracket, and the middle lifting roller 36 is rotated and connected between the "┌┐"-shaped brackets, which can also facilitate the conveyor belt 30 to pass through and realize the designed lifting stroke. When in use, the controller controls the servo drive motors connected to each roller and controls them independently, and the controller controls the connected drive motors and controls them independently.

[0106] See also Figure 1 , Figure 2The front end of the lower screening plate 11 is located directly above the outer fixed frame section 31, and the inner telescopic frame section 32 faces the screening device 300. When the inner telescopic frame section 300 is extended, it extends into the inner side of the annular track 56, and is vertically located between the tea accommodating bin 50 in the positive state and the transmission belt. The fixing method of the conveyor belt device 200 is the same as described above. When the inner telescopic frame section 300 is extended, it will not interfere with the tea accommodating bin 50, and after retracting, it will not affect the circumferential circulation movement of the tea accommodating bin 50. In steps 1) and 2), the large and small fresh tea leaves on the lower screening plate 11 move toward the front end of the screening box 7 with the vibration, and evenly fall onto the conveyor belt 30 of the conveyor belt device 200 after reaching the extended end of the lower screening plate 11. The inner telescopic frame section 32 extends into the inner side of the circular track 56 and is located directly above the tea storage bin 50 in the forward state. After the fresh tea leaves are transported to the conveyor belt section on the inner telescopic frame section 32, the inner telescopic frame section 32 quickly retracts, and the fresh tea leaves on the corresponding conveyor belt section fall with their own weight and are naturally spread on the leaf suction partition 51 of the tea storage bin 50. The process is logically controlled by the controller. Because the screening process of the screening device 300 is not continuous, but takes one cycle of the tea storage bin 50 as one step, the vibration device 100 and the conveyor belt device 200 do not need to work continuously, and the operating time and beat are consistent with the screening device 300, and the effective supply of fresh tea leaves to be screened can be maintained.

[0107] See also Figure 1 , Fig.19 and Fig. 20 , the identification and grasping device 400 for implementing step 4) includes a camera recognition unit 71, also in two sets, which photograph and recognize the fresh tea leaves classified by specifications on the first conveyor belt 63 and the second conveyor belt 65 one-to-one. The camera recognition unit 71 is connected to the mechanical gripper unit 72 by signal. The mechanical gripper unit 72 is used to grasp tea leaves of different specifications according to the recognition of the camera recognition unit 71, that is, to grasp the possibly mixed tea leaves of smaller specifications from the classified tea leaves of larger specifications, and to grasp the possibly mixed tea leaves of larger specifications from the classified tea leaves of smaller specifications. The camera recognition unit 71 and the mechanical gripper unit 72 are arranged at intervals along the conveying direction of the conveyor belt just above one end of the conveyor belt extending out of the circular track 56. A spreading unit 70 is also provided on the side of the camera recognition unit 71 away from the mechanical gripper unit 72, which is used to evenly spread the classified tea leaves on the conveyor belt for identification; see Figure 1 A collecting mechanism 73 is provided on the outer side of the transmission belt, and the mechanical gripper unit 72 is constructed to move back and forth between the transmission belt and the collecting mechanism 73 so as to move the grabbed fresh tea leaves to the collecting mechanism 73.

[0108] Specifically, the spreading unit 70 includes two inclined toothed rake rollers and one transverse toothed rake roller, both of which are horizontally arranged above the conveyor belt and rotatably connected to the gantry frame fixed to the roller frame where the conveyor belt is located, and the two inclined toothed rake rollers together form a V-shape with an opening facing the incoming material direction, and the fresh tea leaves transported by the transmission belt are spread evenly by rotating the rake teeth, and the transverse toothed rake roller is located at the rear, further spreading the fresh tea leaves evenly in the transverse direction. The camera recognition unit 71 includes a plurality of cameras, which are connected to the gantry frame at intervals in the transverse direction and are located behind the transverse toothed rake rollers, and are used to shoot and recognize the evenly spread fresh tea leaves, which is more accurate and convenient for the subsequent mechanical gripper unit 72 to accurately grasp. The mechanical gripper unit 72 adopts multiple gripper structures in an array group, and the figure shows 9 gripper structures in a 3×3 array. Each gripper structure can be raised and lowered, and can move forward, backward, left and right within the projection range of the small grid; the collection mechanism 73 includes roller conveyor belts that are parallel to the same height as the outside of the conveyor belt, and a storage box is provided under the end of the roller conveyor belt. The multiple gripper structures of the mechanical gripper unit 72 are connected as a whole to a gantry mounted on the conveyor belt and the roller conveyor belt in a horizontal sliding manner. During use, with the screening of the tea holding bin 50 in one circle, the smaller tea leaves and the larger tea leaves fall onto the stationary first conveyor belt 63 and the second conveyor belt 65 respectively, and then the conveyor belt moves forward and passes through the spreading unit 70 to be evenly spread, and is scanned and identified by the camera recognition unit 71, and stops under the mechanical gripper unit 72, and the mechanical gripper unit 72 grabs the tea leaves through the gripper structure at the corresponding position according to the identification of the camera recognition unit 71; then the conveyor belt continues to move forward, and the tea leaves of different specifications are classified and fall into the boxes corresponding to the end of the conveyor belt; the mechanical gripper unit 72 slides horizontally to the outside, puts the grabbed tea leaves on the roller conveyor belt, and sends them to the box corresponding to the end of the roller conveyor belt, and the whole automatic classification process is completed, and the boxes of tea leaves of the same specifications can be manually gathered together later.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for screening fresh tea leaves, characterized in that: The steps include: 1) removing impurities from fresh tea leaves to be screened; 2) conveying the fresh tea leaves to be screened after the impurities are removed to the screening device; 3) screening the fresh tea leaves to be screened by a screening device, and classifying them into at least two types of fresh tea leaves of different specifications; The screening device comprises a tea accommodating bin with an open upper end; a horizontal leaf suction partition is laid in the middle of the tea accommodating bin, and a plurality of densely distributed air suction holes are penetrated on the leaf suction partition; an air pressure sensor or a gas flow sensor is also provided in the tea accommodating bin below the leaf suction partition; an air suction pump is connected to the bottom wall of the tea accommodating bin, and the air suction pump is used to form a negative pressure inside the tea accommodating bin below the leaf suction partition; the air suction pump signal is connected to a controller for adjusting the operating power of the air suction pump, and the air pressure sensor or the gas flow sensor is connected to the controller signal; the tea accommodating bin is movably connected to a motion mechanism, and the motion mechanism is constructed to be able to invert the tea accommodating bin from a positive state with its upper end open upward to an inverted state with its upper end open downward, and to make the tea accommodating bin in the inverted state stay at a first position and a second position respectively; In step 2), the tea storage bin is placed in a forward state, and the fresh tea leaves to be screened are spread flat on the leaf suction partition; Step 3) includes: 3.1) the controller controls the air suction pump to operate and form a negative pressure inside the tea storage bin below the leaf suction partition, thereby forming suction force on the fresh tea leaves laid on the leaf suction partition through the air suction holes; 3.2) The movement mechanism inverts the tea storage bin from the forward state to the inverted state, and makes the tea storage bin stay in the first position; 3.3) The controller controls to reduce the operating power of the suction pump, and the smaller tea leaves fall under the action of their own weight due to the reduced suction force; 3.4) The movement mechanism moves the tea storage bin to the second position and stops there; 3.5) The controller further controls to reduce the operating power of the suction pump or stops the operation of the suction pump, and the larger tea leaves fall under the action of their own weight due to the reduced suction force; Thereby achieving the classification of fresh tea leaves of different specifications.

2. The method for screening fresh tea leaves according to claim 1, characterized in that: The method further comprises: step 4) selecting the fresh tea leaves of different specifications remaining in the classified fresh tea leaves; The method is implemented based on a fresh tea leaf screening production line, which includes the screening device and further includes: A vibration device for implementing the impurity removal in step 1); A conveyor belt device, used to implement the conveying in step 2); Identify and grasp the device, used to implement the selection in step 4).

3. The method for screening fresh tea leaves according to claim 2, characterized in that: The vibration device includes a fixed support seat, and spring units are respectively provided at the four corners of the upper surface of the support seat, and the screening box is connected through four spring units, and the screening box is provided with an upper and lower screening plate, and the top of the screening box is connected with a vibrator; one of the spring units corresponds to each of the two sides of the front and rear ends of the screening box; the spring unit includes a bottom plate, and is connected to the support seat through the bottom plate, and a vertical spiral compression spring is provided on the upper surface of the bottom plate, and is connected to the top hinge seat directly above through the spiral compression spring, and a horizontal connecting hole is penetrated through the top hinge seat, and the connecting hole faces the side of the screening box; the two sides of the front end of the screening box are respectively protruding outwardly with transverse rotating shafts and are rotatably inserted into the connecting holes of the top hinge seat corresponding to the outside, and the transverse rotating shafts on both sides are coaxial so that the screening box can be rotated by the transverse rotating shafts to adjust the inclination; the two sides of the rear end of the screening box are plugged into the connecting holes of the top hinge seat corresponding to the outside through the transverse plug-in shafts with adjustable positions, so as to adapt to the rotation adjustment of the screening box; The screening plate at the lower layer extends forward from the screening box body so as to be connected with the conveyor belt device.

4. The method for screening fresh tea leaves according to claim 3, characterized in that: The conveyor belt device comprises an outer fixed frame section extending horizontally, one end of the outer fixed frame section is telescopically connected to the inner telescopic frame section along the length direction of the outer fixed frame section, and the ends of the outer fixed frame section and the inner telescopic frame section which are far away from each other are respectively provided with conveying rollers for installing the conveyor belt, and a tensioning and holding unit is connected below the outer fixed frame section; the tensioning and holding unit comprises two steering rollers arranged at intervals along the length direction of the outer fixed frame section, the two steering rollers are rotatably connected to the bottom of the outer fixed frame section, and the axial direction is parallel to the axial direction of the conveying roller, and three lifting rollers are arranged at intervals between the two steering rollers, and the axial directions of the three lifting rollers are parallel to the axial direction of the conveying roller and are all lifted and connected to the bottom of the outer fixed frame section; a conveyor belt is connected between the two conveying rollers, and the conveyor belt section at the lower part between the two conveying rollers is S-shaped and passes around each steering roller and lifting roller in turn; The end of the screening plate at the lower layer of the vibrating device extending out of the screening box is located directly above the outer fixed frame section; the inner telescopic frame section faces the screening device.

5. The method for screening fresh tea leaves according to claim 4, characterized in that: The movement mechanism comprises an annular track in the shape of an oval circle, two straight sections of the annular track in the shape of an oval circle are arranged horizontally and respectively located at the upper and lower sides in the vertical direction, the tea storage bin is slidably connected to the annular track, and during the sliding process of the tea storage bin along the annular track, its upper end opening is always facing the inner side of the annular track, and when the tea storage bin slides along the annular track to the upper straight section, the first position and the second position can be formed respectively; storage mechanisms are respectively arranged below the first position and the second position, and the storage mechanism comprises a transmission belt, the transmission belt passes through the inner side of the annular track, and the end of the transmission belt away from the conveyor belt device extends out of the annular track and a storage box is arranged below; When the inner telescopic frame section of the conveyor belt device is extended, it extends into the inner side of the annular track and is vertically located between the tea accommodating bin in the forward state and the transmission belt.

6. The method for screening fresh tea leaves according to claim 5, characterized in that: The tea storage bin is in a rectangular shape. A plurality of air pressure sensors or gas flow sensors are provided inside the tea storage bin, which are respectively connected to both sides of the tea storage bin and spaced apart along its length direction; a plurality of air pumps are provided, which are spaced apart along the length direction of the tea storage bin.

7. The method for screening fresh tea leaves according to claim 5, characterized in that: The identification and grasping device includes a camera recognition unit, which is used to photograph and identify the fresh tea leaves on the conveyor belt. The camera recognition unit signal is connected to a mechanical gripper unit. The mechanical gripper unit is used to grasp fresh tea leaves of different specifications according to the recognition results of the camera recognition unit. The camera recognition unit and the mechanical gripper unit are spaced apart along the conveying direction of the transmission belt and are located just above one end of the transmission belt extending out of the circular track.

8. The method for screening fresh tea leaves according to claim 7, characterized in that: A spreading unit is also provided on the side of the camera recognition unit away from the mechanical gripper unit, which is used to spread the fresh tea leaves on the conveyor belt evenly for identification; A collecting mechanism is arranged on the outer side of the transmission belt, and the mechanical gripper unit is constructed to move back and forth between the transmission belt and the collecting mechanism so as to move the grabbed fresh tea leaves to the collecting mechanism.

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