Lamina cut tobacco production line suitable for medium and thin cigarettes and method of lamina cut tobacco production line

Abstract

The invention discloses a tobacco strip shred making production line and method matched with medium and fine cigarettes, and the production line comprises a re-dried tobacco strip loose and uniform distribution device, a foreign matter removing machine, a multi-stage vibrating screen classification screening device, a fixed-distance size splitting machine, a shred cutter, a tobacco shred conveyor and the like. The size distribution of the tobacco strips is controlled, and grading slitting of large tobacco strips and efficient screening of medium tobacco strips are achieved. The vibration sieve plate is of a space curved surface structure constructed on the basis of an orthogonal cosine wave curve, the loose and uniform distribution and screening efficiency of the tobacco lamina is effectively improved, the breakage rate is reduced, and the integrity of the tobacco lamina is protected. And the tobacco cutter is used for cutting the screened middle tobacco sheets into tobacco shreds conforming to the specifications of middle and thin cigarettes, so that the forming requirements of the middle and thin cigarettes are met. By means of the production line and the method, the tobacco shred quality stability and the tobacco shred making efficiency can be remarkably improved, the tobacco shred loose end and loose defect occurrence rate is reduced, and the production line and the method are suitable for high-quality tobacco shred preparation of medium-fine cigarettes.

Description

Technical Field

[0001] The invention belongs to the technical field of tobacco sheet cutting and processing technology and cigarette production, and particularly relates to a tobacco sheet cutting production line and method suitable for medium and slim cigarettes. Background Art

[0002] Medium-slim cigarettes have been a key area of ​​tobacco product structural optimization in recent years. Their circumference diameter typically ranges from 5.0 to 6.4 mm, significantly smaller than conventional cigarettes (approximately 7.7 mm in diameter). As cigarette diameter decreases, cigarette-making machines place higher demands on tobacco supply stability and forming quality, posing new challenges to the tobacco-making process and the adaptability of tobacco structure.

[0003] During the rolling process of existing cigarette-making machines, tobacco shreds must pass through a wire guide channel into the forming section, where they are synchronously rolled with the cigarette paper to complete the filling and shaping of the cigarette. This wire guide channel features a tapered, narrowing structure with a large entrance and a small exit. Its primary function is to guide loose tobacco shreds onto the cigarette paper and gradually compact them as they are pushed forward, forming them into cylindrical cigarette rods that meet the diameter specifications of medium-slim cigarettes. This ensures that the tobacco shreds can be smoothly and evenly rolled with the cigarette paper, completing the shaping and forming of the cigarette.

[0004] However, existing cigarette-making machines and tobacco-making processes are primarily designed for conventional-diameter cigarettes, with tobacco cut lengths generally controlled at 30-100mm. At this stage, the tobacco has a moderate moisture content and is relatively flexible. While this type of tobacco is suitable for the wider guide channels of conventional cigarettes, for medium and thin cigarettes, due to the smaller diameter and more compact structure of the guide channels, tobacco cuts are prone to entanglement, bridging, or irregular accumulation within the channels. This results in intermittent and uneven feed, leading to quality defects such as insufficient filling (empty heads) or uneven density (loose) at the cigarette heads. This seriously affects the continuity of tobacco feed and the stability of forming, making it difficult to meet the higher requirements for guide adaptability and forming accuracy required by medium and thin cigarettes.

[0005] To address these issues, existing processes typically subject prepared conventional tobacco to a further crushing process to shorten its length, or, during the threshing and re-roasting process, adjust the roller gap and sieve size to reduce the tobacco sheets to approximately 3 cm or less, in order to produce even shorter tobacco. However, both of these solutions significantly increase the tobacco crushing rate, increasing the proportion of tobacco dust and ash, resulting in raw material waste and fluctuations in cigarette filling density, affecting product quality stability.

[0006] The present invention is proposed to solve at least one of the above problems. Summary of the Invention

[0007] In recent years, medium and thin cigarettes have gradually become the focus of cigarette product structure upgrades due to their advantages such as low tar release, compact structure, and delicate taste. Correspondingly, higher requirements are placed on the size control, cutting accuracy, and filling value consistency of the tobacco used. However, the existing tobacco strip making process is generally adapted to conventional cigarettes. The cutting length is long and the size distribution is discrete. It is difficult to effectively prepare high-quality tobacco that meets the requirements of medium and thin cigarette making. This can easily lead to structural quality defects such as insufficient filling (empty heads) or uneven density (loose) in the finished cigarettes, affecting the uniformity of the flavor and the consumer experience.

[0008] The purpose of the present invention is to provide a tobacco strip production line and a processing method suitable for medium and thin cigarettes. By reconstructing the size grading, cutting strategy and shredding linkage process of tobacco strips, a multi-stage screening and processing system suitable for the characteristics of medium and thin cigarettes is established, and the tobacco strip size and shred specifications are accurately controlled from the source. The shortcomings of conventional shred-making processes in size control, grading accuracy and structural adaptability are systematically solved, and efficient preparation and stable output of tobacco strips for medium and thin cigarettes are achieved, the incidence of defects such as empty and loose cigarettes is effectively reduced, and product consistency and quality stability are improved.

[0009] The technical solution adopted in the present invention is:

[0010] A first aspect of the present invention provides a tobacco strip production line suitable for medium and slim cigarettes, the production line comprising:

[0011] The redried tobacco strips loosening and uniform distribution device 1 is used to uniformly loosen the redried tobacco strips;

[0012] A foreign body removal machine 2, whose input end is connected to the output end of the redried tobacco strip loosening and uniform distribution device 1, is used to remove metal foreign bodies in the tobacco strips;

[0013] The first hole vibrating screen 3, whose input end is connected to the output end of the foreign matter rejector 2, is used to separate the tobacco flakes into large tobacco flakes and medium tobacco flakes according to particle size;

[0014] A first size slitting machine 4, whose input end is connected to the large-sheet cigarette output end of the first hole vibrating screen 3, is used to cut the large-sheet cigarette into medium-sheet cigarettes;

[0015] The second hole vibrating screen 5, whose input end is connected to the output end of the first size slitting machine 4, is used to screen the cut tobacco sheets again and output medium-sized tobacco sheets and remaining large tobacco sheets;

[0016] The second size cutter 6, whose input end is connected to the large-sheet cigarette output end of the second hole vibrating screen 5, is used to cut the remaining large-sheet cigarettes into medium-sheet cigarettes again;

[0017] The conveyor 7 has its input end connected to the first hole vibrating screen 3, the second hole vibrating screen 5 and the medium-cut tobacco output end of the second size slitting machine 6, respectively, for centrally conveying all medium-cut tobacco;

[0018] The third hole vibrating screen 8, whose input end is connected to the output end of the conveyor 7, is used to screen the medium-sized cigarettes and output broken cigarettes smaller than 5mm and cigarettes larger than 5mm;

[0019] A shredder, the input end of which is connected to the output end of the third hole vibrating screen 8 for cutting the tobacco sheets larger than 5 mm into shredded tobacco;

[0020] The fourth hole vibrating screen has a first input end connected to the output end of the cutter, and a second input end connected to the output end of the third hole vibrating screen 8 for cigarettes smaller than 5 mm, for screening out hard stems and cigarette dust smaller than 3 mm;

[0021] The tobacco cut conveyor has an input end connected to the output end of the tobacco cut larger than 3 mm of the fourth hole vibrating screen, and is used to convey the tobacco cut to subsequent processes.

[0022] Preferably, the re-roasted tobacco flakes loosening and uniform distribution device 1, the first hole vibrating screen 3 and the second hole vibrating screen 5 are all vibrating trough conveying structures, which include a first vibrating screen plate 100 and a first conveying plate 101;

[0023] The conveying plate 101 is a rigid flat transition plate, which is closely connected to the rear end of the vibrating screen plate 100 and is used to receive and guide the screened or loosened tobacco sheets into subsequent processing equipment.

[0024] Preferably, the first vibrating screen plate 100 in the re-roasted tobacco flake loosening and uniform distribution device 1, the first hole vibrating screen 3, and the second hole vibrating screen 5 have the same structure, and are all vibrating screen plates with a spatial curved surface. The spatial curved surface is formed in a three-dimensional space coordinate system constructed with two mutually perpendicular coordinate axes. The surface of the first vibrating screen plate 100 is formed by the superposition of a first cosine wave trajectory along the width direction and a second cosine wave trajectory along the length direction, and its mathematical function is:

[0025] The first trajectory equation is:

[0026] y = 10cos(2πx / λ1), where wavelength λ1 = 62.832 mm and wave height 20 mm;

[0027] The second trajectory equation is:

[0028] y = 10cos(2πz / λ2), wavelength λ2 = 125.664 mm, wave height 20 mm;

[0029] Among them, the direction along the first track is the width direction of the vibrating screen plate, and the direction along the second track is the length direction of the screen plate, that is, the loose and uniform transportation direction of the tobacco material. The spatial curved surface structure is used to improve the uniform loosening effect of the tobacco material during transportation.

[0030] Preferably, the first size slitting machine 4 and the second size slitting machine 6 have the same structure, and both include:

[0031] A rotating shaft 403 arranged in the horizontal direction;

[0032] A plurality of size adjustment sleeve units 407 are slidably mounted on the outer periphery of the rotating shaft 403;

[0033] Each size adjustment sleeve unit 407 is provided with a functional part, which is a circular cutter 404 or a pressure wheel 405. The plurality of size adjustment sleeve units 407 are sequentially spaced along the length direction of the rotating shaft 403, so that the circular cutter 404 and the pressure wheel 405 are spaced apart.

[0034] The rotating shaft 403 is provided with a sliding groove structure for guiding and positioning the size adjustment sleeve unit 407, as well as a threaded fastening structure for locking the sleeve in position. The size adjustment sleeve unit 407 is equipped with a guiding protrusion or a groove portion that cooperates with the sliding groove structure, allowing it to slide and position along the axial direction of the rotating shaft and be locked by the threaded fastening structure. The spacing between adjacent size adjustment sleeve units 407 can be set through position adjustment and locking to achieve the 25.40mm fixed-distance slitting requirement between adjacent circular cutters 404. Preferably, the sliding groove structure and threaded fastening structure can adopt a dovetail groove with a pressure plate screw structure, or a sliding keyway with a fastening screw structure, to achieve a combined effect of guiding sliding and reliable locking.

[0035] The pressing wheel 405 is used to apply appropriate pressure to the tobacco sheets to control their moving path, thereby improving the cutting accuracy and the flatness of the tobacco sheets.

[0036] Preferably, the size slitting machine further comprises a dovetail adjustment frame, a tool fine-tuning hand wheel 402, an anvil 408 and a bearing 409;

[0037] The dovetail adjustment frame includes an upper adjustment frame 401 and a lower adjustment frame 406 arranged in the vertical direction and at least partially overlapping, and the two can slide relative to each other in the vertical direction;

[0038] The upper adjustment frame 401 is used to mount the rotating shaft 403, and a bearing 409 is provided inside the upper adjustment frame 401 to support and limit the rotation of the rotating shaft 403;

[0039] The lower adjustment frame 406 is used to mount the cutting board 408;

[0040] By adjusting the relative height between the upper and lower adjustment frames, the radial distance between the circular cutter 404 and the anvil 408 is adjusted to control the cutting depth;

[0041] The tool fine-tuning hand wheel 402 is disposed at the lower portion of the dovetail adjustment frame, and is used to drive the lower adjustment frame 406 to move in the vertical direction, thereby adjusting the cutting gap between the circular cutter 404 and the anvil 408 .

[0042] The tool fine-tuning handwheel 402 is connected to an adjusting screw, which is installed on the upper adjusting frame 401 in a rotatable but axially fixed manner and is threadedly connected to the lower adjusting frame 406; by twisting the tool fine-tuning handwheel 402, the adjusting screw rotates and drives the lower adjusting frame 406 to rise or fall in the vertical direction, thereby realizing the radial distance adjustment between the circular cutter 404 and the anvil 408 to control the cutting depth.

[0043] Preferably, the upper adjustment frame 401 is provided with a through hole and a bearing for supporting the rotation of the adjustment screw and limiting its axial movement to form a stable lifting guide structure. Preferably, the third hole vibrating screen is a vibrating trough conveying structure, which includes a second vibrating screen plate 801 and a second conveying plate 802;

[0044] The second conveying plate 802 is a rigid flat transition plate, which is closely connected to the rear end of the second vibrating screen plate 801 and is used to receive and guide the screened tobacco sheets into subsequent processing equipment;

[0045] The second vibrating screen plate 801 is a vibrating screen plate having a spatial curved surface. The spatial curved surface is formed based on a three-dimensional spatial coordinate system constructed with two mutually perpendicular coordinate axes. The vibrating screen plate surface is formed by the superposition of a first cosine wave trajectory along the width direction and a second cosine wave trajectory along the length direction. The mathematical function is:

[0046] The first cosine wave trajectory:

[0047] y = 5cos(2πx / λ1), where wavelength λ1 = 31.416 mm and wave height 10 mm;

[0048] Second cosine wave trajectory:

[0049] y = 5cos(2πz / λ2), where wavelength λ2 = 62.832 mm and wave height 10 mm;

[0050] Among them, the direction along the first cosine wave trajectory is the width direction of the vibrating screen plate, and the direction along the second cosine wave trajectory is the length direction of the vibrating screen plate, that is, the loose and uniformly distributed conveying direction of the tobacco sheet material. The spatial curved surface structure is used to improve the uniformity and looseness of the tobacco sheet material during conveying.

[0051] Preferably, the third hole vibrating screen 8 and the fourth hole vibrating screen are both the vibrating trough conveying structure described above, and both include the same vibrating screen specifications and screen plate structures, the difference being that the screening apertures are φD=5mm and φD=3mm respectively;

[0052] The sieve apertures of the first vibrating screen 3, the second vibrating screen 5, the third vibrating screen 8 and the fourth vibrating screen are respectively:

[0053] First hole vibrating screen (3): φD = 25.4 mm;

[0054] Second hole vibrating screen (5): φD = 25.4 mm;

[0055] The third hole vibrating screen (8): φD = 5 mm;

[0056] Fourth hole vibrating screen: φD=3mm.

[0057] Preferably, the shredder is used to cut the medium-sized tobacco sheets screened by the third-hole vibrating screen 8 into tobacco shreds suitable for rolling medium and thin cigarettes, and the width of the tobacco shreds is not more than 0.5 mm and the length is 15-25 mm; the shredder is arranged at the output end of the third-hole vibrating screen 8, and includes at least a cutting component for realizing continuous cutting of tobacco sheets and a shred conveying structure for guiding the directional conveying of tobacco shreds.

[0058] The shredder can adopt the mature disc-type shredder equipment in the existing technology, such as the YTFQ-250 tobacco slice shredder, the QSJ-C multi-knife disc shredder or the GHQ300 high-speed precision shredder. The above equipment all have adjustable cutter spacing, a stable conveying structure and a rotary cutter disc suitable for high-frequency cutting, which can meet the requirements of processing medium and thin cigarette tobacco with a cutting width of no more than 0.5mm and a length controlled within the range of 15 to 25mm. In specific applications, it is also possible to select an intelligent shredder with automatic feeding, wire output detection and fault shutdown functions based on the actual production capacity requirements of the silk production line to further improve the degree of automation and cutting accuracy of the production line. It should be noted that the above-mentioned recommended shredder equipment are all existing mature technologies, and the applicant does not claim rights to them. They are only used as the technical selection basis for the realization of the shredding function in the device of the present invention.

[0059] In addition, the vibrating trough conveying structure adopted by the present invention is based on the existing mature vibrating trough conveyor technology platform, and is mainly used to achieve loose transportation and uniform distribution of tobacco leaf materials. The core difference is that the conveying surface of the traditional vibrating trough conveyor is replaced by a composite structure including a vibrating screen plate and a conveying plate. The vibrating trough conveying structure can be directly modified based on the existing mature vibrating trough conveyor, without the need to redesign the entire machine structure. Only the conveying surface components need to be replaced to achieve efficient transportation and screening for the special physical and chemical properties of tobacco leaves. This solution simplifies the difficulty of equipment updates, and takes into account both material processing efficiency and equipment stability. It is suitable for multiple screening and conveying links in the tobacco leaf silk production line of the present invention.

[0060] A second aspect of the present invention provides a method for preparing shredded tobacco for medium-slim cigarettes using the shredded tobacco production line according to the first aspect, characterized in that it comprises the following steps:

[0061] (1) The re-roasted tobacco sheets are evenly loosened by the re-roasted tobacco sheet loosening and uniform distribution device 1 to improve the looseness and conveying uniformity of the tobacco sheets. After the tobacco sheets are passed through the foreign matter removal machine 2 to remove metal debris, they are conveyed to the first hole vibrating screen 3 via the conveyor 21;

[0062] (2) The redried tobacco strips are preliminarily screened by particle size through the first hole vibrating screen 3 and divided into large tobacco strips and medium tobacco strips. The large tobacco strips are conveyed to the first size slitting machine 4 through the first conveying plate 101 and cut at a fixed distance to obtain medium tobacco strips. The above-mentioned cut materials then enter the second hole vibrating screen 5 for further screening. The screened materials, i.e., the large tobacco strips that have not been fully cut, will enter the second size slitting machine 6 for further cutting into medium tobacco strips.

[0063] The medium-sized cigarettes cut by the first size slitting machine 4 and the second size slitting machine 6, together with the medium-sized cigarettes directly screened by the first hole vibrating screen 3, are respectively fed into the conveyor 7 through the first feed hopper 301, the second feed hopper 501 and the third feed hopper 601 arranged at the corresponding discharge ends, and are uniformly transported to the third hole vibrating screen 8 for subsequent screening processing.

[0064] (3) All the medium-sized cigarettes are transported to the third vibrating screen 8 by the conveyor 7 for 5 mm aperture screening to separate the broken cigarettes smaller than 5 mm and the cigarettes larger than 5 mm. The cigarettes larger than 5 mm enter the subsequent shredding stage, and the broken cigarettes smaller than 5 mm are transported to the fourth vibrating screen for subsequent screening.

[0065] (4) Using a shredder, the tobacco flakes larger than 5 mm screened by the third hole vibrating screen 8 are cut into shredded tobacco to form shredded tobacco that meets the requirements of medium and thin cigarettes;

[0066] (5) The shredded tobacco and the broken tobacco smaller than 5 mm separated by the third hole vibrating screen 8 are screened through the fourth hole vibrating screen, and the hard stems and tobacco dust smaller than 3 mm are removed to ensure that the tobacco particle size is consistent and the impurities are fully removed;

[0067] (6) A tobacco conveyor is used to transport qualified tobacco larger than 3 mm screened by the fourth hole vibration screen to the subsequent cigarette production process, thereby realizing continuous and efficient transportation of tobacco.

[0068] The "large tobacco flakes" mentioned in the present invention refer to tobacco flakes that meet the industry's general standards and have a particle size greater than 25.4 mm, and "medium tobacco flakes" refer to tobacco flakes with a particle size between 12.5 mm and 25.4 mm. This classification is set based on the particle size grade classification standards of tobacco flakes during the silk-making process, and is used to guide the grading treatment of the screening and cutting processes to achieve precise control of the processing particle size of tobacco flakes.

[0069] Beneficial effects of the present invention:

[0070] 1. Adjusting the tobacco structure to improve the quality of medium and thin cigarettes: Through multi-stage screening and size cutting of tobacco strips, large tobacco strips are gradually processed into medium-sized tobacco strips with stable dimensions. Their entry into the tobacco-making section is controlled, effectively concentrating the final tobacco strip length at around 3mm. This avoids the problem of sticking and clumping caused by a high proportion of long tobacco strips (30-100mm), significantly improving the tobacco uniformity and filling stability of medium and thin cigarettes during the rolling process, and reducing the risk of density fluctuations and structural defects in the finished cigarettes.

[0071] 2. The redried tobacco strip loosening and distribution device provided by this invention features a key optimization of the traditional vibrating screen structure. Its core improvement lies in replacing the original flat vibrating screen plate with a spatially undulating surface constructed by superimposing two orthogonal cosine waves. This structure creates an array of peaks and troughs on the vibrating screen surface. Combined with a drive system with a vibration amplitude of up to 40mm, this significantly improves loosening efficiency and even distribution under high-flow tobacco strip conditions, effectively alleviating the accumulation and blockage caused by tobacco strip sticking and clumping.

[0072] Compared to conventional flat screens or rake-and-stud structures, this spatially undulated surface structure offers significant advantages: It simultaneously superimposes disturbances of varying frequencies and amplitudes in both the direction of movement and the transverse direction of the tobacco strips, creating a three-dimensional disturbance field that quickly breaks up the aggregated structure of the tobacco strips and improves loosening efficiency. Compared to the unidirectional vibration limitations of flat structures, this design significantly enhances the deagglomeration effect and is suitable for applications with high flow rates and high tobacco strip concentration.

[0073] In addition, the array-type trough structure forms multiple natural material diversion channels during the vibration process, guiding the tobacco flakes to move in the set direction, avoiding material retention, accumulation or backflow on the conveying surface, effectively preventing repeated collisions and breakage caused by local blockages, and improving conveying smoothness.

[0074] Compared with the traditional rake device that only intermittently moves local tobacco sheets, this structure achieves full-surface, low-impact uniform transportation through the continuous action of wave peaks and troughs, so that the material is evenly distributed across the entire width of the screen plate, providing a stable and reliable material state for subsequent foreign matter removal and screening processes.

[0075] The curvature of the spatial surface changes continuously with a gentle transition. Even when operating at an amplitude of 40mm, the vibration contact with the tobacco leaves is flexibly cushioned, eliminating sharp corner collisions and significantly reducing the risk of breakage. Compared to rigid toggle mechanisms or flat screen plates, this structure provides better tobacco leaf protection and process stability.

[0076] 3. The 25.4mm, 5mm, and 3mm hole vibrating screens in this invention all utilize a spatially structured vibrating screen plate constructed based on an orthogonal cosine wave curve. The screen holes are precisely distributed along the wave troughs, and circular screening holes are machined in the direction of the surface normal. This effectively achieves graded screening and screening of tobacco flakes at different stages. Compared to conventional flat vibrating screens or drum screens, this structure offers superior screening efficiency, higher screening efficiency, and stronger material protection.

[0077] Specifically, these screening devices have the following technical advantages:

[0078] The screening holes are arranged according to the trough path of the orthogonal cosine wave curve on the surface of the vibrating screen plate and processed along the normal direction to ensure that the tobacco leaves can more easily enter the screen holes during the vibration process, effectively realize the separation of large tobacco leaves, medium tobacco leaves, fine tobacco and tobacco dust, and achieve multi-stage screening precision control.

[0079] Compared with the traditional flat sieve plate that only disturbs in a single plane, the spatial corrugated sieve plate simultaneously disturbs the tobacco particles in both the vertical and horizontal directions during the vibration process, thereby enhancing the deagglomeration effect, which is especially effective in the primary screening of large tobacco sheets (25.4mm hole vibrating screen) and the fine screening of tobacco (3mm hole vibrating screen).

[0080] The three-dimensional curved surface has the characteristics of continuous and flexible transition, which avoids sharp impact and frequent accumulation and backflow of materials on the plate surface during the screening process, effectively protecting the structural integrity of the tobacco leaves. It is especially suitable for the thin-tobacco making process that requires high integrity of the tobacco leaves.

[0081] After accurate grading of large tobacco pieces by 25.4mm hole vibration screening, combined with two-stage size cutting process, large size tobacco pieces are avoided to be mixed into the medium tobacco stream, and cutting uniformity is improved; at the same time, 5mm and 3mm hole vibration screens can accurately remove fine tobacco dust and hard stem, and ensure that the material consistency entering the cutting machine and the subsequent tobacco processing link is better.

[0082] 4、The technical solution adopts two-stage screening combined with two-stage cutting process to realize accurate cutting of large tobacco pieces. The cutting size is determined by the spacing t between adjacent circular knives, t = 25.4mm, which is accurately adjusted by adjusting the axial length of the sleeve unit 407 to ensure that the cutting size is controllable. The cutting machine adopts a dovetail groove adjusting frame, the material is selected from HT200 and is treated by scraping and grinding to realize micron-level guide rail precision, and the stability and precision of cutting are improved. The knife adopts a circular cutter, which significantly reduces the tobacco piece crushing rate and is superior to the traditional roller cutter. In addition, thanks to the tobacco piece loose and uniform distribution technology, the foreign matter removing machine can efficiently remove metal impurities, effectively protect the knife life, and ensure the continuous stability of the cutting process.

[0083] 5、In the 5mm hole vibration screening and 3mm hole vibration screening process, the screening plate used can replace the "nostril screen" or "fish scale screen" widely used in the tobacco industry, which has the technical advantages of smooth screening, low crushing rate and high screening efficiency. In the 3mm hole vibration screening process, the screening plate used can not only effectively screen out the tobacco dust and tobacco fines in the tobacco, but also screen out a certain number of hard "stem", and the screening principle is based on the difference in physical properties: the hard "stem" has high hardness and density, and generates a large momentum and impulse during the vibration screening process, which is easy to penetrate the spatial screening hole designed according to the cosine curve and is effectively separated; and the tobacco is not easy to penetrate the screening hole due to its flexibility, variable size and easy adhesion characteristics, and the screening effect depends on the reasonable setting and optimization of the screening hole diameter.

[0084] DRAWINGS

[0085] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0086] Figure 1 A device process flow diagram suitable for a tobacco piece tobacco processing line for medium and fine cigarette;

[0087] Figure 2 A loose and uniform distribution device structure diagram for re-dried tobacco pieces;

[0088] Figure 3This is a schematic diagram of the design of the vibrating screen plate of the device for loosening and evenly distributing redried tobacco flakes according to the present invention, wherein the X direction is the width direction of the vibrating screen plate, and the Z direction is the length of the vibrating screen plate;

[0089] Figure 4 This is a schematic diagram of the structure of the equipment for completing two screening and two size cutting processes of tobacco strips according to the present invention;

[0090] Figure 5 This is a schematic diagram of the design of the first vibrating screen plate of the present invention;

[0091] Figure 6 This is a schematic diagram of the design of the screening holes of the first vibrating screen plate of the present invention;

[0092] Figure 7 It is a schematic diagram of the structure of the first size slitting machine and the second size slitting machine;

[0093] Figure 8 Additional assembly diagrams for the shaft bearing, circular cutter, and cutting board;

[0094] Figure 9 This is a schematic diagram of the third hole vibrating screen structure;

[0095] Figure 10 This is a schematic diagram of the design of the second vibrating screen plate;

[0096] Figure 11 This is a schematic diagram of the principle of the screening plate having the stem separation function during the cigarette screening process.

[0097] Figure numerals: 1. Re-roasted tobacco sheet loosening and uniform distribution device; 100. First vibrating screen plate; 101. First conveyor plate; 2. Foreign matter rejector; 21. Conveyor; 3. First hole vibrating screen; 301. First feed hopper; 4. First size slitting machine; 401. Upper adjustment frame; 402. Tool fine-tuning hand wheel; 403. Rotating shaft; 404. Circular cutter; 405. Pressing wheel; 406. Lower adjustment frame; 407. Adjusting sleeve unit; 408. Anvil; 409. Bearing; 5. Second hole vibrating screen; 501. Second feed hopper; 6. Second size slitting machine; 601. Third feed hopper; 7. Conveyor; 8. Third hole vibrating screen; 801. Second vibrating screen plate; 802. Second conveyor plate; 803. Fourth feed hopper. DETAILED DESCRIPTION

[0098] The present invention is further described in detail below with reference to the examples, but is not intended to limit the present invention. Any changes or improvements made based on the teachings of the present invention fall within the scope of protection of the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in the art or in the product instructions shall be followed.

[0099] Example 1

[0100] This embodiment provides a tobacco strip production line suitable for medium and thin cigarettes, which is mainly used for screening, cutting at fixed distances, centralized transportation and precision cutting of redried tobacco strips to obtain high-quality tobacco that meets the specifications of medium and thin cigarettes. Figure 1 As shown, the production line includes a redried tobacco sheet loosening and uniform distribution device 1, a foreign matter rejector 2, a first-hole vibrating screen 3, a first-size slitting machine 4, a second-hole vibrating screen 5, a second-size slitting machine 6, a conveyor 7, a third-hole vibrating screen 8, a shredder, a fourth-hole vibrating screen, and a tobacco conveyor;

[0101] The specific structure and connection relationship of each functional module of the production line are as follows:

[0102] like Figure 2-6 As shown, a device 1 for loosening and evenly distributing redried tobacco strips is installed at the front end of the production line, and is used to initially loosen and evenly spread the redried tobacco strips. Its conveying surface includes a first vibrating screen plate 100 and a first conveying plate 101. The first vibrating screen plate 100 adopts a spatially curved surface structure composed of two sets of orthogonal cosine wave trajectories. The spatially curved screen plate has sieve holes arranged along the wave trough path. Under the action of vibration, the tobacco strip particles are displaced, flipped, and dispersed, thereby achieving loose and even spreading, avoiding material aggregation or cohesion, and improving the consistency of the material state in the subsequent screening and cutting steps. The mathematical function of the spatial surface of the first vibrating screen plate 100 is y=f(x,z), the equation of the first trajectory is y=10cos(2πx / λ1), the wavelength λ1=62.832mm, and the wave height is 20mm. The equation of the second trajectory is y=10cos(2πz / λ2), the wavelength λ1=125.664mm, and the wave height is 20mm. Among them, the direction of the first trajectory corresponds to the width direction of the vibrating screen plate, and the direction of the second trajectory corresponds to the length direction of the screen plate, that is, the loose and uniformly distributed conveying direction of the tobacco material.

[0103] The loosely distributed tobacco flakes are guided and slid to the foreign matter removal machine 2 by the rigid first conveyor plate 101 with a certain inclination. Its flat and stable rigid surface is used to achieve smooth transition and directional conveying of the tobacco flakes, effectively avoiding material accumulation and deviation, thereby achieving efficient removal of occasional metal foreign matter and larger hard impurities in the tobacco flakes, and ensuring the safe and stable operation of the equipment in the subsequent precision cutting link.

[0104] In this embodiment, the first vibrating screen plate 100 measures 840.05 mm in width and 1319.47 mm in length, with a vibration amplitude of 15 mm. This meets the uniform distribution requirements for conventional tobacco flake flow rates and medium to high-volume tobacco production. For high-volume or high-volume tobacco flake processing scenarios, the vibrating screen plate length can be appropriately extended based on actual operating conditions to improve loosening capacity and screen surface efficiency, ensuring that flakes are fully loosened and evenly distributed even at high throughputs.

[0105] The foreign body removal machine 2 is installed at the rear end outlet of the loosening and uniform distribution device to remove metal foreign bodies and large hard impurities from the tobacco flakes, ensuring the safe and stable operation of subsequent precision equipment such as the cutter;

[0106] The first hole vibrating screen 3 is a vibrating trough screening structure with a screen hole diameter of 25.4mm. It is used to screen the primary tobacco flakes into "large flakes" (particle size greater than 25.4mm) and "medium flakes" (particle size 12.5-25.4mm) according to particle size. The large flakes are introduced into the first size slitting machine 4, while the medium flakes are directly sent to the subsequent centralized conveying link;

[0107] like Figure 7 、 8 The first size slitting machine 4 has the same structure as the second size slitting machine 6, and both include: a rotating shaft 403 arranged in the horizontal direction, a plurality of size adjustment sleeve units 407 are sleeved on the outer periphery of the rotating shaft, and circular cutters 404 and pressure wheels 405 are arranged in a staggered manner on the sleeves;

[0108] The rotating shaft 403 is mounted on the upper adjustment frame 401 via a bearing 409 and is arranged opposite to the anvil 408 on the lower adjustment frame 406, forming an adjustable cutting mechanism. The lower adjustment frame is adjusted relative to the upper adjustment frame via a tool fine-tuning hand wheel (402) to precisely control the cutting gap between the cutter and the anvil, ensuring a stable cutting depth and consistent cutting size, ultimately cutting large tobacco sheets into medium-sized sheets.

[0109] The second hole vibrating screen 5 has the same structure as the first hole vibrating screen, and the screen hole is also φ25.4mm. It is used to re-screen the medium-sized cigarettes output by the first size slitting machine and remove the remaining large cigarettes; the remaining large cigarettes are further fed into the second size slitting machine 6 for secondary cutting;

[0110] The second size slitting machine 6 has the same structure as the first size slitting machine 4 and is used to further cut the residual large tobacco into medium tobacco slices to improve the overall particle size consistency;

[0111] The conveyor 7 is used to collect and stably convey the medium-sized tobacco leaves outputted from the first-hole vibrating screen 3, the second-hole vibrating screen 5 and the second size slitting machine 6 to the third-hole vibrating screen 8;

[0112] The third hole vibrating screen 8 is a vibrating groove structure with a screen hole diameter of φ5mm. It is used to screen out the broken tobacco with a particle size of less than 5mm in the medium-sized tobacco, and only retain the tobacco with a particle size greater than 5mm to be sent to the shredding stage;

[0113] The shredder is arranged at the output end of the third hole vibrating screen 8, and is used to cut qualified medium-sized tobacco into thin shreds with a length of 15-25mm and a width of no more than 0.5mm, which is suitable for the specifications of medium and thin cigarettes. In this embodiment, the HZQ-350 high-speed disc knife shredder is adopted. The equipment includes: a servo-driven feeding mechanism, an adjustable feed roller assembly, a high-speed rotating cutter disc unit and a wire outlet guide assembly. The speed of the cutter disc is adjustable, and the number and angle of the cutters can be configured according to the thickness of the tobacco slices and the specifications of the cigarettes. It has functions such as constant linear speed cutting control, rapid tool replacement, fault alarm and temperature control protection. The shredder operates stably, cuts fine and uniform shreds, and can effectively control the width of the tobacco shreds to no more than 0.5mm, avoid problems such as crushing and breaking, and ensure that the shape of the tobacco shreds is suitable for rolling and burns evenly;

[0114] The fourth hole vibrating screen is also in the form of a vibrating groove screen plate with a screen hole diameter of φ3mm. It is used to simultaneously process the tobacco output from the cutter and the broken tobacco screened by the third hole vibrating screen 8 to remove tobacco powder with a particle size of less than 3mm and hard "stems";

[0115] The tobacco conveyor is installed after the fourth hole vibrating screen and is used to stably convey qualified tobacco larger than 3mm to the subsequent cigarette production section, realizing continuous and efficient output of tobacco.

[0116] In the above structure, the 25.4mm hole, 5mm hole and 3mm hole vibrating screens used are all vibrating screen plates designed based on the spatial cosine wave surface. The screen holes are arranged along the trough path and opened in the normal direction, which significantly improves the screening efficiency and screening rate, while reducing the breakage rate of tobacco leaves. It is particularly suitable for tobacco leaf making processes that require control of particle size distribution and impurity removal.

[0117] Specifically, such as Figure 6 As shown, the surface of the 25.4mm hole vibrating screen is a spatial curved surface. A three-dimensional spatial coordinate system is established on mutually perpendicular orthogonal planes. The mathematical function of the surface spatial curved surface is y=f(x,z). The equation of the first trajectory is y=10cos(2πx / λ1), the wavelength λ1=62.832mm, and the wave height is 20mm. The equation of the second trajectory is y=10cos(2πz / λ2), the wavelength λ2=125.664mm, and the wave height is 20mm. The direction along the first trajectory is the width direction of the vibrating screen plate, and the direction along the second trajectory is the length direction of the screen plate, that is, the loose and uniform conveying direction of the tobacco material.

[0118] The mesh holes of the 25.4 mm hole vibrating screen (the first hole vibrating screen 3 and the second hole vibrating screen 5) are manufactured as follows: the sieve holes are manufactured at the trough points of the cosine curve y=10cos(2πx / λ2) of the first trajectory on the vibrating screen plate and according to the cosine curve y=10cos(2πz / λ1), and 5 sieve holes are evenly distributed within a wavelength λ2=125.664 mm, with an aperture of φD=25.4 mm. The processing direction of the sieve holes is manufactured according to the normal of the cosine curve y=10cos(2πz / λ1), that is, the processing directions of the sieve holes on the crest and the trough are parallel to each other, the processing direction of the sieve holes on the wave surface has an angle with the z-axis, and its normal vector is calculated by the derivative of y=10cos(2πz / λ1);

[0119] The design width B of the vibrating screen plate is 840.05 mm, and the design length L is 1319.47 mm. Similarly, the length of the vibrating screen plate can be extended.

[0120] On the trough line within a wavelength of λ2 = 125.66 mm, five sieve holes (202) are machined using the average interpolation method, with an aperture of φD1 = 25.4 mm. The coordinate positions of each hole are machined along the normal vector direction of the trough line. The coordinate positions of each hole are:

[0121]

[0122] In the formula, x0 and z0 represent the position of the starting hole 0;

[0123] n represents the trough number of y=10cos(x / λ2×2π), and k represents the hole number on the y=10cos(z / λ1×2π) curve.

[0124] Starting hole 0 position, x0 = λ1 / 2 = 62.832 / 2 = 31.416 mm, z0 = λ2 / 4 = 125.664 / 4 = 31.416 mm.

[0125] If we calculate the position of the n=5th trough line on the x-axis to y=10cos(x / λ2×2π), and the k=11th hole on the y=10cos(z / λ1×2π) curve, the coordinates are:

[0126]

[0127] The normal vector is used to punch holes in the 3D sieve holes on the trough line. Since the trough curve y = 10cos(z / λ1×2π) is in the coordinate system yoz, the component of the normal vector on the X axis is 0. The following calculation is performed in the coordinate system yoz:

[0128] The first-order derivative of y=10cos(z / λ1×2π) is:

[0129]

[0130] It is the slope of the tangent line P of the curve passing through the coordinate point z, so the slope of the normal line N at the coordinate point z is:

[0131] N=-1 / y .

[0132] The vector of the normal N can be found.

[0133] Calculating the normal vector (or direction cosine) of a point on a curved surface is a fundamental technology in NC machine tool manufacturing or precision testing. In CNC numerical control, it can control the movement direction of the tool or probe.

[0134] The third vibrating screen 8 adopts a wave-shaped screen plate structure. The arrangement of the screen holes on the screen plate is similar to that of the first vibrating screen plate 100, and is also based on a spatial cosine wave surface design. The arrangement and processing of the screen holes are as follows:

[0135] like Figure 9 、 10 The mesh holes of the third hole vibrating screen 8 (also known as the 5mm hole vibrating screen) are made as follows: at the trough point of the cosine curve y=5cos(2πx / λ1) of the first trajectory on the vibrating screen plate 301, and according to the cosine curve y=5cos(2πz / λ2), 5 sieve holes are evenly distributed within a wavelength λ2=62.832mm, with an aperture of φD=5mm, and the processing direction of the sieve holes is made according to the normal of the cosine curve y=5cos(2πz / λ2), that is, the processing directions of the sieve holes on the crest and the trough are parallel to each other, and the processing direction of the sieve holes on the wave surface has an angle with the length direction of the third hole vibrating screen 8, and its normal vector is calculated by the derivative of y=5cos(2πz / λ2);

[0136] like Figure 10 The design width B of the vibrating screen plate 301 is 840.05 mm, and the design length L is 1319.47 mm. The specific technical principle of the screening holes is the same as that of the screening holes on the first hole of the vibrating screen plate 3 .

[0137] The fourth hole vibration screen has the same vibration screen specifications and sieve plate structure as the third hole vibration screen 8 (i.e. 5mm hole vibration screen). The only difference is that the screening aperture is adjusted to

[0138] Example 2

[0139] This embodiment uses the tobacco strip production line described in Example 1, specifically comprising a re-roasted tobacco strip loosening and uniform distribution device 1, a foreign matter remover 2, a first-hole vibrating screen 3, a first-size slitter 4, a second-hole vibrating screen 5, a second-size slitter 6, a conveyor 7, a third-hole vibrating screen 8, a shredder, a fourth-hole vibrating screen, and a tobacco conveyor. This production line can be used to prepare tobacco strips suitable for medium and thin cigarettes. The process steps are as follows:

[0140] (1) The re-roasted tobacco sheets are evenly loosened by the re-roasted tobacco sheet loosening and uniform distribution device 1 to improve the looseness and conveying uniformity of the tobacco sheets. After the tobacco sheets are passed through the foreign matter removal machine 2 to remove metal debris, they are conveyed to the first hole vibrating screen 3 via the conveyor 21;

[0141] (2) The redried tobacco strips are preliminarily screened by particle size through the first hole vibrating screen 3 and divided into large tobacco strips and medium tobacco strips. The large tobacco strips are conveyed to the first size slitting machine 4 through the first conveying plate 101 and cut at a fixed distance to obtain medium tobacco strips. The above-mentioned cut materials then enter the second hole vibrating screen 5 for further screening. The screened materials, i.e., the large tobacco strips that have not been fully cut, will enter the second size slitting machine 6 for further cutting into medium tobacco strips.

[0142] The medium-sized cigarettes cut by the first size slitting machine 4 and the second size slitting machine 6, together with the medium-sized cigarettes directly screened by the first hole vibrating screen 3, are respectively fed into the conveyor 7 through the first feed hopper 301, the second feed hopper 501 and the third feed hopper 601 arranged at the corresponding discharge ends, and are uniformly transported to the third hole vibrating screen 8 for subsequent screening processing.

[0143] (3) All the medium-sized cigarettes are transported to the third vibrating screen 8 by the conveyor 7 for 5 mm aperture screening to separate the broken cigarettes smaller than 5 mm and the cigarettes larger than 5 mm. The cigarettes larger than 5 mm enter the subsequent shredding process, while the broken cigarettes smaller than 5 mm are discharged from the fourth feeding hopper 803 to the conveyor (which can be a mature transfer device such as a belt conveyor) and transported to the fourth vibrating screen for subsequent screening.

[0144] (4) Using a shredder, the tobacco flakes larger than 5 mm screened by the third hole vibrating screen 8 are cut into shredded tobacco to form shredded tobacco that meets the requirements of medium and thin cigarettes;

[0145] (5) The shredded tobacco and the broken tobacco smaller than 5 mm separated by the third hole vibrating screen 8 are screened through the fourth hole vibrating screen, and the hard stems and tobacco dust smaller than 3 mm are removed to ensure that the tobacco particle size is consistent and the impurities are fully removed;

[0146] (6) A tobacco conveyor is used to transport qualified tobacco larger than 3 mm screened by the fourth hole vibration screen to the subsequent cigarette production process, thereby realizing continuous and efficient transportation of tobacco.

[0147] Obviously, the surface of the screening plate in the present technical solution is a spatial curved surface formed by orthogonal intersection of two cosine curves. Since the spatial waveform surface has an array of alternating peaks and troughs, it has low crushing characteristics, and the screening holes are designed on the trough line. Therefore, it has the function of efficiently solving the agglomeration and adhesion of tobacco sheet materials online, matching the simple harmonic vibration amplitude and frequency of the vibration trough, and has high screening efficiency. It is a more classic orthogonal screening. Due to the effect of the sine wave, it also has a better uniform distribution function of tobacco sheet materials.

[0148] like Figure 11 The figure shows a schematic diagram of the principle of separating "stems" from cut tobacco using a φ5mm aperture screening plate. Given that cut tobacco itself is flexible and of varying lengths, and that "stems" are generally harder and denser, they are more likely to gain greater momentum during the vibration screening process, thereby crashing into the sieve holes and being effectively separated. Therefore, the screening plate used in this technical solution, in addition to its basic function of separating ash and cigarette dust, also has an auxiliary removal effect for "stems." Depending on the requirements of different tobacco-making processes, the aperture size of the 3mm hole vibration screen can be flexibly selected between 2 and 3mm to achieve fine control of the particle size and cleanliness of the cut tobacco.

[0149] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and detail without departing from the scope defined by the claims of the present application; the dimensions described in the drawings and embodiments are not related to specific physical objects and are not used to limit the scope of protection of the present application. The physical dimensions can be selected and changed according to actual needs.

Claims

1. A tobacco strip production line suitable for medium and slim cigarettes, characterized in that: The production line comprises: The re-roasted tobacco strips loosening and uniform distribution device (1) is used for uniformly loosening the re-roasted tobacco strips; A foreign matter removal machine (2), the input end of which is connected to the output end of the re-roasted tobacco sheet loosening and uniform distribution device (1), and is used to remove metallic foreign matter from the tobacco sheets; A first hole vibrating screen (3), the input end of which is connected to the output end of the foreign matter rejecting machine (2), and is used to separate the tobacco flakes into large tobacco flakes and medium tobacco flakes according to particle size; A first size slitting machine (4), the input end of which is connected to the large-sheet cigarette output end of the first hole vibrating screen (3), and is used to slit the large-sheet cigarette into medium-sheet cigarettes; A second hole vibrating screen (5), the input end of which is connected to the output end of the first size slitting machine (4), is used to screen the cut tobacco sheets again and output medium-sized tobacco sheets and remaining large tobacco sheets; A second size slitting machine (6), the input end of which is connected to the large-sheet cigarette output end of the second hole vibrating screen (5), and is used to slit the remaining large-sheet cigarettes into medium-sheet cigarettes again; A conveyor (7), the input end of which is respectively connected to the first hole vibrating screen (3), the second hole vibrating screen (5) and the medium-sized cigarette output end of the second size slitting machine (6), for centrally conveying all the medium-sized cigarettes; A third hole vibrating screen (8), the input end of which is connected to the output end of the conveyor (7), is used to screen the middle-sized tobacco sheets and output broken tobacco sheets smaller than 5 mm and tobacco sheets larger than 5 mm; A shredder, the input end of which is connected to the output end of the third hole vibrating screen (8) for cutting the tobacco sheets larger than 5 mm into shredded tobacco; A fourth hole vibrating screen, the first input end of which is connected to the output end of the shredder, and the second input end of which is connected to the output end of the third hole vibrating screen (8) for filtering out hard stems and cigarette dust smaller than 3 mm; The tobacco cut conveyor has an input end connected to the output end of the tobacco cut larger than 3 mm of the fourth hole vibrating screen, and is used to convey the tobacco cut to subsequent processes.

2. The silk production line according to claim 1, characterized in that: The re-roasted tobacco flake loosening and uniform distribution device (1), the first hole vibrating screen (3) and the second hole vibrating screen (5) are all vibrating trough conveying structures, each comprising a first vibrating screen plate (100) and a first conveying plate (101); The conveying plate (101) is a rigid flat transition plate, which is closely connected to the rear end of the vibrating screen plate (100) and is used to receive and guide the screened or loosened tobacco sheets into subsequent processing equipment.

3. The silk production line according to claim 1, characterized in that: The first vibrating screen plate (100) in the re-roasted tobacco flake loosening and uniform distribution device (1), the first hole vibrating screen (3), and the second hole vibrating screen (5) have the same structure, and are all vibrating screen plates with a surface that is a spatial curved surface. The spatial curved surface is formed in a three-dimensional space coordinate system constructed with two mutually perpendicular coordinate axes. The surface of the first vibrating screen plate (100) is formed by the superposition of a first cosine wave trajectory along the width direction and a second cosine wave trajectory along the length direction. The mathematical function thereof is: The first trajectory equation is: y = 10cos(2πx / λ1), where wavelength λ1 = 62.832 mm and wave height 20 mm; The second trajectory equation is: y = 10cos(2πz / λ2), wavelength λ2 = 125.664 mm, wave height 20 mm; Among them, the direction along the first track is the width direction of the vibrating screen plate, and the direction along the second track is the length direction of the screen plate, that is, the loose and uniform transportation direction of the tobacco material. The spatial curved surface structure is used to improve the uniform loosening effect of the tobacco material during transportation.

4. The tobacco strip production line for medium and slim cigarettes according to claim 1, characterized in that: The first size slitting machine (4) and the second size slitting machine (6) have the same structure and both comprise: A rotating shaft (403) arranged in a horizontal direction; A plurality of size adjustment sleeve units (407) are slidably mounted on the outer periphery of the rotating shaft (403); Each size adjustment sleeve unit (407) is provided with a functional part, which is a circular cutter (404) or a pressure wheel (405). A plurality of size adjustment sleeve units (407) are sequentially spaced along the length direction of the rotating shaft (403), so that the circular cutter (404) and the pressure wheel (405) are spaced apart. The rotating shaft (403) is provided with a sliding groove structure for guiding and positioning the size adjustment sleeve unit (407), and a threaded fastening structure for locking the sleeve position; the size adjustment sleeve unit (407) is provided with a guiding protrusion or a groove portion that cooperates with the sliding groove structure, which can be slid and positioned along the axial direction of the rotating shaft and locked by the threaded fastening structure. The spacing between adjacent size adjustment sleeve units (407) can be set by position adjustment and locking to achieve the 25.40mm fixed distance slitting requirement between adjacent circular cutters (404); The pressing wheel (405) is used to apply appropriate pressure to the tobacco sheets to control their moving path, thereby improving the cutting accuracy and the flatness of the tobacco sheets.

5. The silk production line according to claim 4, characterized in that: The size slitting machine also includes a dovetail adjustment frame, a tool fine-tuning hand wheel (402), an anvil (408) and a bearing (409); The dovetail adjustment frame comprises an upper adjustment frame (401) and a lower adjustment frame (406) which are arranged in a vertical direction and at least partially overlap each other, and the two can slide relative to each other in the vertical direction; The upper adjustment frame (401) is used to install the rotating shaft (403), and a bearing (409) is provided inside the upper adjustment frame to support and limit the rotation of the rotating shaft (403); The lower adjustment frame (406) is used to install the cutting board (408); By adjusting the relative height between the upper and lower adjustment frames, the radial distance between the circular cutter (404) and the anvil (408) is adjusted to control the cutting depth; The tool fine-tuning hand wheel (402) is arranged at the lower part of the dovetail adjustment frame and is used to drive the lower adjustment frame (406) to move in the vertical direction, thereby adjusting the cutting gap between the circular cutter (404) and the anvil (408).

6. The silk production line according to claim 1, characterized in that: The third hole vibrating screen is a vibrating trough conveying structure, which includes a second vibrating screen plate (801) and a second conveying plate (802); The second conveying plate (802) is a rigid flat transition plate, which is closely connected to the rear end of the second vibrating screen plate (801) and is used to receive and guide the screened tobacco sheets into subsequent processing equipment; The second vibrating screen plate (801) is a vibrating screen plate having a spatial curved surface. The spatial curved surface is formed based on a three-dimensional spatial coordinate system constructed with two mutually perpendicular coordinate axes. The vibrating screen plate surface is formed by superimposing a first cosine wave trajectory along the width direction and a second cosine wave trajectory along the length direction. The mathematical function thereof is: The first cosine wave trajectory: y = 5cos(2πx / λ1), where wavelength λ1 = 31.416 mm and wave height 10 mm; Second cosine wave trajectory: y = 5cos(2πz / λ2), where wavelength λ2 = 62.832 mm and wave height 10 mm; Among them, the direction along the first cosine wave trajectory is the width direction of the vibrating screen plate, and the direction along the second cosine wave trajectory is the length direction of the vibrating screen plate, that is, the loose and uniformly distributed conveying direction of the tobacco sheet material. The spatial curved surface structure is used to improve the uniformity and looseness of the tobacco sheet material during conveying.

7. The silk production line according to claim 1, characterized in that: The third hole vibrating screen (8) and the fourth hole vibrating screen are both the vibrating trough conveying structure as claimed in claim 6, and both include the same vibrating screen specifications and screen plate structures, the difference being that the screening apertures are φD=5mm and φD=3mm respectively; The sieve apertures of the first hole vibrating screen (3), the second hole vibrating screen (5), the third hole vibrating screen (8) and the fourth hole vibrating screen are respectively: First hole vibrating screen (3): φD = 25.4 mm; Second hole vibrating screen (5): φD = 25.4 mm; The third hole vibrating screen (8): φD = 5 mm; Fourth hole vibrating screen: φD=3mm.

8. The silk production line according to claim 1, characterized in that: The shredder is used for cutting the medium-sized tobacco sheets screened by the third-hole vibrating screen (8) into tobacco shreds suitable for rolling medium-slim cigarettes, wherein the width of the tobacco shreds is not greater than 0.5 mm and the length is 15-25 mm. The shredder is arranged at the output end of the third-hole vibrating screen (8) and comprises at least a cutting assembly for realizing continuous cutting of the tobacco sheets and a shred conveying structure for guiding the directional conveying of the tobacco shreds.

9. A method for preparing shredded tobacco for medium and thin cigarettes using the shredded tobacco production line according to any one of claims 1 to 8, characterized in that: The steps include: (1) The re-roasted tobacco sheets are evenly loosened by using a re-roasted tobacco sheet loosening and uniform distribution device (1) to improve the looseness and conveying uniformity of the tobacco sheets. After the tobacco sheets are passed through a foreign matter removal machine (2) to remove metal debris, they are conveyed to a first-hole vibrating screen (3) via a conveyor (21); (2) The redried tobacco flakes are preliminarily screened by particle size through a first hole vibrating screen (3) and divided into large flakes and medium flakes, wherein the large flakes are conveyed to a first size slitting machine (4) through a first conveying plate (101) and cut at a fixed distance to obtain medium flakes; the cut material then enters a second hole vibrating screen (5) for further screening, and the screened material, i.e., the large flakes that have not been fully cut, enters a second size slitting machine (6) for further cutting into medium flakes; The medium-sized cigarettes cut by the first size slitting machine (4) and the second size slitting machine (6) are fed into a conveyor (7) together with the medium-sized cigarettes directly screened by the first hole vibrating screen (3), and are uniformly transported to the third hole vibrating screen (8) for subsequent screening processing; (3) All the medium-sized cigarettes are transported to the third-hole vibrating screen (8) through the conveyor (7) for 5 mm aperture screening to separate the broken cigarettes smaller than 5 mm and the cigarettes larger than 5 mm. The cigarettes larger than 5 mm enter the subsequent shredding stage, and the broken cigarettes smaller than 5 mm are transported to the fourth-hole vibrating screen for subsequent screening. (4) using a shredder to cut the tobacco sheets larger than 5 mm screened by the third hole vibrating screen (8) into shredded tobacco, so as to form shredded tobacco in accordance with the requirements of medium and thin cigarettes; (5) Screening the shredded tobacco and the broken tobacco smaller than 5 mm screened out by the third hole vibrating screen (8) through the fourth hole vibrating screen, removing the hard stems and tobacco dust smaller than 3 mm, ensuring that the tobacco particle size is consistent and the impurities are fully removed; (6) A tobacco conveyor is used to transport qualified tobacco larger than 3 mm screened by the fourth hole vibration screen to the subsequent cigarette production process, thereby realizing continuous and efficient transportation of tobacco.

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