Strand separation and tobacco recovery device and method for tobacco shreds in a cigarette making process

Abstract

This invention provides a device and method for separating tobacco scraps and recovering tobacco shreds in the cigarette manufacturing process. The tobacco scraps are fed into a primary vibrating screen via an elevator. "Hard, piercing" scraps are captured by an orthogonal curved screen plate and cylindrical screening holes with alternating dot matrix, separating tobacco dust and scraps with a diameter less than d1. The remaining material is fed into a secondary vibrating screen, where curved guide strips, a size-controlled screen plate, screening holes, separation holes, and a separation surface control the separation of hard scraps with a length greater than d2 and poor plasticity. Flexible tobacco shreds pass sequentially through the screening holes, separation holes, and separation surface, and are finally fed into a tobacco collection box. This invention provides high loosening force, screening efficiency, and low breakage rate for tobacco scraps, and accurately separates scraps from tobacco scraps, improving the recovery rate and quality of tobacco shreds.

Description

Technical Field

[0001] This invention relates to the field of cigarette manufacturing technology, and is applied to the separation of stems and stalks and the recycling of tobacco shreds in tobacco scraps. Specifically, it relates to a device and method for separating stems and stalks and recycling tobacco shreds in the cigarette manufacturing process. Background Technology

[0002] In the tobacco processing industry, "stem" is a very important term, and its research has been ongoing alongside the development of cigarette technology. Generally speaking, "stem" refers to tobacco stems in the tobacco shreds that resemble toothpicks in shape, are not expanded, or whose expansion effect does not meet the requirements of the cigarette rolling process. Its undesirable physical characteristics, such as size, hardness, or shape, negatively impact the cigarette rolling process or cigarette quality. For example, an excessively high "stem" content or poor "stem" characteristics can lead to uneven combustion, uneven burning surfaces, and "blooming" in the cigarette. Furthermore, hard stems can puncture and tear the cigarette paper during the rolling process, directly affecting cigarette quality, such as sensory experience and smoking sensation.

[0003] "Stems" originate from the fact that tobacco leaves cannot be completely de-stemmed during the threshing and re-drying process; the leaves inevitably contain stems. This leads to the unavoidable presence of "stems" in tobacco shred production. Furthermore, during the production of "tobacco stem shreds" using tobacco stems, substandard stem shreds are sometimes mixed into the finished tobacco product, forming "stems." Therefore, the purpose of separating "stems" is to qualitatively isolate the stem shreds that negatively impact cigarette quality. Consequently, based on the description of the properties of "stems," "stem separation" is a very difficult task.

[0004] Currently, a stem-skewer separation process is included in the pre-processing of cigarettes using cigarette rolling machines. The basic principle is to separate harmful stems and other impurities using air separation technology. These air-separated stems and impurities are collectively referred to as "tobacco scraps." Large cigarette manufacturers generate approximately 4-5 tons of "tobacco scraps" containing these stems daily. Because the weight and suspension velocity differences between some tobacco shreds and stems are not significant, these "tobacco scraps" contain not only stems but also a large amount of tobacco shreds. While the exact percentage of tobacco shreds in these scraps is difficult to quantify precisely, it is estimated to be over 50-60%. Therefore, recycling these tobacco shreds is essential.

[0005] In view of the above problems, the inventors of this invention have finally obtained this invention after a long period of research and practice. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a device and method for separating stems and scraps from tobacco scraps and for recycling tobacco scraps during the cigarette manufacturing process. This improves the accuracy of stem and scrap separation, the quality of tobacco scraps, and the recycling rate, thereby saving on expensive tobacco scrap costs and enhancing the quality of cigarette production.

[0007] The technical solution adopted in this invention is as follows:

[0008] On the one hand, a device for separating tobacco scraps and recycling tobacco scraps in the cigarette making process is provided, comprising: a primary vibrating screen and a secondary vibrating screen; the primary vibrating screen is provided with a curved screen plate, and the secondary vibrating screen is provided with a size control screen plate;

[0009] The upper surface of the curved screen plate is a spatial surface constructed from orthogonal sinusoidal basis functions. Let the length L of the material's directional movement be the x-axis, the width B perpendicular to the x-axis be the z-axis, and the direction perpendicular to the xz plane be the y-axis. Let the spatial surface be y = f(x,z). Then, within the x-axis section at the origin of the coordinate system, the equation of the curve on the spatial surface y = f(x,z) is y = cos(x), and the coordinates of any point on the spatial surface y = f(x,z) satisfy x = sin(z) and... If y = cos(x), then the standard spatial surface equation of y = f(x,z) is y = f(x,z) = cos(x - sin(z)); the curved sieve plate has a plurality of first screening holes, which are cylindrical holes machined on the spatial surface y = f(x,z) perpendicular to the xz plane. The intersection of the hole and the spatial surface is a continuous three-dimensional spatial curve C. The first screening holes are distributed on the spatial surface y = f(x,z) at equal intervals at each wavelength λ.

[0010] The upper surface of the size-controlled sieve plate is provided with a plurality of second screening holes, and a separation hole with the same diameter is connected directly below the second screening holes; the lower surface of the size-controlled sieve plate forms a plurality of parallel and equally spaced material discharge grooves; directly below the separation holes is a separation space connected thereto, one side of which is closed by a separation curved surface, and the other side is open and connected to the adjacent material discharge groove; the length L1 direction of the size-controlled sieve plate is the directional movement direction of the material, and the width B1 direction is perpendicular to the length L1 direction; the second screening holes are distributed along a sine curve function along the length L1; the upper surface of the size-controlled sieve plate is equipped with a plurality of curved guide strips extending along the L1 direction, and the curved guide strips are located between two adjacent second screening holes in the width B1 direction.

[0011] Furthermore, the diameter of the separation hole is d2, and an arc with a radius equal to d2 is formed with any point on the circumference of the separation hole as the center. This arc is on the separation surface, which is a surface of revolution.

[0012] Furthermore, the second screening holes are distributed along length L1 according to a sine curve function, with the center of each screening hole lying on the sine curve, as shown in the equation: The wavelength is λ = 2π; each of the second sieve holes on the sine curve in the width B1 direction is sequentially translated.

[0013] Furthermore, the curved guide bar is designed according to a sine curve, with the equation as follows: The wavelength is λ = 2π.

[0014] Furthermore, the diameter of the first screening hole is d1, which is less than d2, and the height h of the first screening hole is not less than 3mm, with the minimum h value appearing at the trough.

[0015] Furthermore, the material discharge groove is an open through-hole that passes through the circumference of the separation hole and is tangent to the separation surface. The minimum distance from this tangent surface to the center of the separation hole is x, and the range of x is:

[0016] Furthermore, the length L1 of the size-controlled sieve plate is designed as an integer multiple of the wavelength λ, and can be manufactured in segments; the designed length L1 of the size-controlled sieve plate is within 25 wavelengths λ.

[0017] Furthermore, the three-dimensional spatial curve C-shaped opening of the first screening hole on the curved surface of the curved screen plate, and the edge of the material discharge chute outlet on the size control screen plate, are manually deburred or chamfered to prevent the tobacco from being broken or blocked.

[0018] Furthermore, the stem-skewer separation and tobacco shred recovery device also includes an elevator, a conveyor plate, a stem-skewer collection box, a stem-skewer discharge chute, a tobacco shred discharge chute, a tobacco shred collection box, a tobacco dust and stem-skewer collection cylinder, and a tobacco dust discharge chute; the elevator is connected to the front end of the primary vibrating screen, and the end of the primary vibrating screen and the front end of the secondary vibrating screen are connected via the conveyor plate; the tobacco dust discharge chute is located below the curved screen plate, and the tobacco dust and stem-skewer collection cylinder is located below the outlet of the curved screen plate; the tobacco shred discharge chute is located below the size-controlled screen plate, and the tobacco shred collection box is located below the outlet of the tobacco shred discharge chute; the end of the secondary vibrating screen is connected to the stem-skewer discharge chute, and the stem-skewer collection box is located below the outlet of the stem-skewer discharge chute.

[0019] On the other hand, a method for separating tobacco scraps from stems and recycling tobacco scraps in the cigarette making process is provided, using the above-mentioned device for separating tobacco scraps from stems and recycling tobacco scraps in the cigarette making process.

[0020] Tobacco scraps are fed into a primary vibrating screen via an elevator. After passing through a curved screen plate and a cylindrical first screening hole, the hard, piercing stems are captured by the three-dimensional curved holes C on the curved surface. Tobacco dust and stems with a diameter smaller than d1 are screened out and fed into a tobacco dust and stem collection cylinder through a tobacco dust discharge chute. The remaining material is fed into a secondary vibrating screen via a screening conveyor. Using curved guide strips, a size control screen plate, a second screening hole, a separation hole, a separation curved surface, and a discharge chute, hard stems with poor plasticity and a length greater than d2 are screened out and fed into a stem collection box through a stem discharge chute. Plastic and flexible tobacco shreds are passed sequentially through the second screening hole, separation hole, separation curved surface, and discharge chute, and then fed into the tobacco collection box through a tobacco shred discharge chute.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] From a cigarette manufacturing perspective, stems pose a risk of puncturing and tearing the cigarette paper. From a cigarette quality perspective, the content and physical form of stems affect cigarette quality, such as sensory aspects like smoking experience. To address the risk of stems puncturing and tearing the cigarette paper, this invention utilizes cylindrical screening holes. The openings are continuous, closed three-dimensional curves, with the opening surfaces situated at crests, troughs, and wave surfaces, forming a lattice-like three-dimensional space. Furthermore, the center of the screening hole on the wave surface is the unique orthogonal point on the chord curve y = cos(x), and its normal vector forms an optimal 45° projection angle with the bottom surface of the curved screen plate. Therefore, the screening holes achieve optimal material capture and ejection effects. If the screening holes... Make diameter The following stems can enter through cylindrical sieve holes using their own momentum (impulse). Similar to the "borrowing arrows with straw boats" tactic, it's generally believed that this poses a risk of puncturing or tearing cigarette paper. Because tobacco shreds are highly malleable and flexible, once they exceed a certain length, they are difficult to pass through the cylindrical sieve openings. Thus, separation is achieved.

[0023] In existing mature tobacco stem separation and tobacco shred recycling production lines, steam, drums, and vibrating troughs are used to solve the problems of clumped tobacco shreds and loosening. The orthogonal screening of this invention has a highly efficient loosening effect because the curved surface of the screen plate is sinusoidal. From a physical and mathematical perspective, its elasticity is alternating, thus it has an extremely low material breakage rate. At the same time, in addition to the harmonic effect, the sinusoidal surface significantly expands the screening area and improves performance, which is beneficial to the development of tobacco machinery.

[0024] The diameter of the stem is greater than For example, if the stem length is greater than 3.2mm, or greater than d2 (6-10mm), such as greater than 6mm or 10mm, this invention provides a two-stage vibrating screen for controlling the size measurement and separation technology, namely, a size-controlling screen plate. This plate integrates metrological, geometric, and physical characteristics. It can measure or determine the stem size within a certain spatial angle range. The separation surface is a spatial rotational surface, and the normal at any point on the surface points to the circumference of the separation hole or screening hole. Mechanically speaking, stems larger than d2 will be ejected by the vibrating screen. Tobacco shreds or "tobacco stem shreds" are plastic and flexible; their natural size varies. Once they enter the separation hole, they will most likely enter the discharge chute, thus achieving stem separation. Theoretically, the size-controlling screen plate also measures the physical hardness of the stems again.

[0025] The separation or screening holes and curved guide bars all use sine functions. The design, with its amplitude less than 1, allows tobacco fragments to flow smoothly and evenly on the vibrating screen. The curved guide strips balance the material velocity, unlike a flat screen which moves like a "frog jumping," while the sine wave extends the path of the screened material. Therefore, the size control screen plate is highly effective. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 A schematic diagram of the overall structure of the stem separation and tobacco shred recovery device according to an embodiment of the present invention is shown;

[0028] Figure 2 A schematic diagram of the structure of a primary vibrating screen according to an embodiment of the present invention is shown;

[0029] Figure 3 A schematic diagram showing the curve equation of the curved sieve plate according to an embodiment of the present invention in a three-dimensional spatial coordinate system is provided.

[0030] Figure 4 The following are three design views of a curved sieve plate according to an embodiment of the present invention;

[0031] Figure 5 The front and side views of the curved sieve plate and the first screening hole according to an embodiment of the present invention are shown.

[0032] Figure 6 It shows Figure 5 A schematic diagram of the BB section in the diagram;

[0033] Figure 7 A schematic diagram of the structure of a two-stage vibrating screen according to an embodiment of the present invention is shown;

[0034] Figure 8 A schematic diagram of the design of the second screening hole, separation hole, separation surface, and material discharge chute on the size control screen plate according to an embodiment of the present invention is shown.

[0035] Figure 9 A schematic diagram showing the dimensional design of the second screening aperture according to an embodiment of the present invention is shown;

[0036] Figure 10 It shows Figure 9 A schematic diagram of section AA in the diagram;

[0037] Figure 11 A schematic diagram of the planar design of a size-controlled sieve plate according to an embodiment of the present invention is shown;

[0038] Figure 12 A three-dimensional structural schematic diagram of a curved guide bar according to an embodiment of the present invention is shown;

[0039] Figure 13 A plan view of a curved guide bar according to an embodiment of the present invention is shown;

[0040] Figure 14 It shows Figure 13 A schematic diagram of the BB section in the diagram;

[0041] Figure 15 A schematic diagram of the stem discharge trough according to an embodiment of the present invention is shown;

[0042] Figure 16 A schematic diagram of the structure of the tobacco shred discharge trough and tobacco dust discharge trough according to an embodiment of the present invention is shown. Detailed Implementation

[0043] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0044] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, unless otherwise explicitly specified.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] The separation of stems and tobacco scraps and the recycling of tobacco scraps have always been among the most critical technologies in the tobacco industry, with the difficulty lying in the determination and separation of their morphology. Research has shown that in the cigarette-making process, the stems that puncture or tear the cigarette paper are hard and have piercing capabilities; stems longer than 6-10 mm can affect cigarette quality. Clumping and tangling of tobacco scraps can be effectively addressed using a vibrating trough screen with a sinusoidal structure. Material observation and analysis of tobacco scraps reveal that stems with a fitted geometric diameter greater than 3 mm are rare, while those longer than 6-10 mm are common. Based on these geometric characteristics of tobacco scraps, the inventors designed relevant size control and separation technologies, effectively solving the problems of stem separation and tobacco recycling.

[0048] like Figure 1As shown, this invention provides a device for separating tobacco scraps from stems and recycling tobacco in the cigarette manufacturing process. The device includes a hoist 2, a primary vibrating screen 3, a curved screen plate 4, a first screening hole 4-1, a conveying plate 5, a secondary vibrating screen 6, a curved guide bar 7, a size-controlled screen plate 8, a second screening hole 8-1, a separation hole 8-7, a separation curved surface 8-8, a discharge chute 8-9, a stem collection box 9, a stem discharge chute 10, a tobacco discharge chute 11, a tobacco collection box 12, a tobacco scrap and stem collection cylinder 13, and a tobacco discharge chute 14. The diameter of the first screening hole 4-1 is d1, the diameter of the second screening hole 8-1 is d2, and the diameter of the separation hole is d2. Tobacco scraps are fed into the primary vibrating screen 3 via the elevator 2 and its conveyor belt 1. The primary vibrating screen 3 has a curved screen plate 4 inside its guard plate 4-2. The curved screen plate 4 and the first screening hole 4-1 separate tobacco dust and stems with a diameter less than d1. The tobacco dust is then fed into the tobacco dust and stem collection cylinder 13 via the tobacco dust discharge chute 14. The remaining material is fed into the secondary vibrating screen 6 via the conveyor plate 5. The secondary vibrating screen 6 has a size control screen plate 8 inside its guard plate 8-2. The curved guide bar 7, the size control screen plate 8, the second screening hole 8-1, the separation hole 8-7, the separation curved surface 8-8, and the discharge chute 8-9 work together to separate stems with a length greater than d2. The stems pass through the conveyor plate 8-5 into the stem discharge chute 10 and are then fed into the stem collection box 9. Tobacco shreds are fed into the tobacco collection box 12 via the tobacco shred discharge chute 11.

[0049] According to the cigarette manufacturing process and quality requirements, the diameter d1 value of the first screening hole 4-1 on the curved screen plate 4 is selected, preferably 2 to 3.2 mm; and the stem length d2 value of the diameter of the second screening hole 8-1 on the size control screen plate 8 is selected, preferably 6 to 10 mm.

[0050] In a preferred embodiment, the diameter of the first screening hole 4-1 of the curved sieve plate 4 is selected as follows: Select the diameter of the second screening hole 8-1 on the size control sieve plate 8 as [value].

[0051] like Figures 2-5 As shown, the upper surface of the curved sieve plate 4 is a spatial surface constructed by orthogonal sine basis functions. Let the length L direction of the material's directional movement be the x-axis, the width B direction perpendicular to the length L x-axis be the z-axis, and the direction perpendicular to the xz plane be the y-axis. The spatial surface is y = f(x,z). Then, in the x-axis section at the origin of the coordinate system, the curve equation on the spatial surface y = f(x,z) is: y = cos(x). The coordinates of any point on the spatial surface y = f(x,z) satisfy: x = sin(z) and y = cos(x). Therefore, the standard spatial surface equation of y = f(x,z) is y = f(x,z) = cos(x - sin(z)).

[0052] See Figure 3Using the sinusoidal basis functions x = αsin(ω1z) and y = b cos(ω2x), a coordinate system is established on an orthogonal surface to construct a spatial surface and design orthogonal surfaces. In the coordinate system, z, y, and x have the same number of units and units of measurement. The wavelength of the smallest positive period of x = αsin(ω1z) is λ1 = 2π / ω1, and ω1 = 2π / λ1; y = b The wavelength of the smallest positive period of cos(ω2x) is λ2 = 2π / ω2, ω2 = 2π / λ2, where α, b, ω1, and ω2 can all be preferred. In a preferred embodiment: ω1 = 1, λ1 = 2π, α = 1, ω2 = 1, λ2 = 2π, b = 1. ω1x and ω2x can be converted by wavelengths λ1 and λ2. In radians, we get: x = sin(z) and y = cos(x); or in length, we get: x = sin(2π / λ×z) and y = cos(2π / λ×x).

[0053] By introducing sinusoidal basis functions into the orthogonal plane to generate a space curve surface, and introducing a parameter t on the z-axis and a parameter t1 reflecting the change in the y-coordinate value, the parametric equation of the space curve is as follows:

[0054]

[0055] In the spatial surface established by the above equations, given a parameter t value, there is a cosine curve that varies with parameter t1, and given a parameter t1 value, there is a sine curve that varies with parameter t. These, on the orthogonal planes establishing the three-dimensional coordinate system, can be simplified to the normalized form of the spatial surface equation y = f(x,z) as follows:

[0056] y = f(x,z) = cos(x - sin(z))

[0057] The condition for y = ±1 to reach its maximum value is: x - sin(z) = kπ → x = kπ + sin(z)

[0058] x = sin(z) (k = 0, peak line)

[0059] x = π + sin(z) (k = 1, trough line)

[0060] ...

[0061] like Figure 3 The text indicates that the wavelength λ has been replaced with a length meter.

[0062] The spatial surface can be designed, modeled, and manufactured in CAD / CAM according to the above equation. Alternatively, it can be manufactured using an NC machine tool according to the formula or by introducing it into a CNC system. Or, a custom sine cutter can be used to execute the sine function equation to complete the manufacturing.

[0063] Let its sinusoidal basis function wave height 2α = 10 mm, wavelength λ = 31.4159 mm, and the thickness H of the curved sieve plate 4 be no less than 13 mm.

[0064] like Figure 5 , Figure 6 As shown, the diameter of the first screening hole 4-1 It is a cylindrical hole machined perpendicular to the xz plane on the spatial curved surface y=f(x,z). The height h of the cylindrical hole is not less than 3mm. The intersection of the cylindrical hole and the spatial curved surface is a continuous three-dimensional spatial curve C.

[0065] The first screening holes 4-1 are distributed on the spatial curved surface y=f(x,z) by being equidistantly distributed on each wavelength λ, with an equidistant value of λ / 4. That is, 5 first screening holes 4-1 are processed on each wavelength. The coordinates of the first reference hole are located at point (0,0,0). They are distributed along the x-axis (length L direction) according to x=cos(z) and along the z-axis (width B direction) according to z=sin(x). Specifically:

[0066] The screen holes on the curved screen plate 4 are machined according to the variation law of sine and cosine curves. The position number is M in the z-axis direction and N in the x-axis direction. Five first screening holes 4-1 are machined on each wavelength λ (minimum period). The coordinate positions are as follows:

[0067]

[0068] M=1, N=1 indicates that the first hole is drilled at the origin of the coordinate system, and the total number of holes is M×N. The above formula is in radians. In a preferred embodiment, the first screening hole 4-1 in the length x-direction section has 305 holes and the width Z-direction has 97 holes.

[0069] The above formula shows that the screen mesh is processed according to the sine curve variation law in the vertical direction, and the screen mesh is positioned at the geometric midpoint of the wave surface between the wave crest, wave trough and wave crest and wave trough.

[0070] The length and width L of the curved sieve plate 4 are designed as integer multiples of the wavelength λ, with the length L not exceeding 80λ and the width B not exceeding 30λ. It can be manufactured and spliced ​​in sections.

[0071] like Figure 4 As shown, in this embodiment, the length L is 76λ, which is 2387.667mm, and the width B is 24λ, which is 754.008mm.

[0072] Furthermore, regarding the curve of the eigenfunction y = f(x) = sin(x), its first derivative is: If we take any two points x1 and x2 on the curve f(x), then the condition for the equations of the tangent lines at points x1 and x2 to be perpendicular is:

[0073] cos(x1)·cos(x2)=-1

[0074] Since -1 ≤ cos(x1) ≤ 1 and -1 ≤ cos(x2) ≤ 1, the condition for satisfying this equation is |cos(x1)| = |cos(x2)| = 1, and cos(x1) and cos(x2) have opposite signs. Therefore, for example, if we take x1 = kπ and x2 = kπ + π, where k is an integer, then the two points x1 and x2 lie on the coordinate axis, located on either side of the inflection point of the equation y = f(x) = sin(x), and their derivatives alternately become 1 and -1, respectively. The angles between the tangent lines passing through x1 and x2 and the positive x-axis are respectively: (i.e., 45°, 135°), therefore, with the y=sin(x) curve, wherever x passes through... k+1 x k+2 The normal vectors of a point are all orthogonal to each other in the plane. This means that "on a sine or cosine curve with an amplitude of 1, there is a unique orthogonal point between any two adjacent crests and troughs, or between a trough and a crest, located at the geometric midpoint between the crests and troughs of the sine or cosine curve, and the normal vectors at adjacent orthogonal points are mutually orthogonal and lie on the wave surface." This has significant meaning in physics because the angle between the normal vectors x1 and x2 at this point and the x-axis is θ. (i.e., 45°) The material ejected from this point travels the farthest in a parabolic trajectory. It balances the conveying, distribution, and loosening performance of the vibrating screen. For y=f(x,z), the geometric midpoint between the peaks and troughs of the sine and cosine curves actually passes through points x1 and x2, and lies on a plane parallel to the XOZ plane. This is also the key reason why the amplitude of 1 was chosen in this invention.

[0075] y = f(x,z) is an orthogonal surface that has excellent loosening force and screening efficiency for tobacco fragments. For example, if (x0, z0) is set on the spatial surface y = f(x,z) = cos(x - sin(z)), then the vector characteristics on this surface can be analyzed:

[0076] 1) Partial derivative with respect to z

[0077] The tangential vector is: S1(0, sin(x0-sin(z))·cos(z), 1)

[0078] f z (x0,z0)=sin(x0-sin(z))·cos(z)

[0079] 2) Partial derivatives with respect to x

[0080] The tangential vector is: S2(1, -sin(x-sin(z0)), 0)

[0081] f x(x0, z0) = -sin(x - sin(z0))

[0082] 3) Normal vector N

[0083] Let the equation of the normal vector N of (x0, z0) on the space surface y = f(x, z) be:

[0084] N = S1 × S2 = (f x (x0, z0), -1, f z (x0,z0))

[0085] That is to say:

[0086] Right now:

[0087] N=(-sin(x-sin(z0)),-1,sin(x0-sin(z))·cos(z))

[0088] 4) Direction cosine of the normal vector N

[0089] If we let α, β, and γ represent the angles between the normal vector and the positive directions of the x, y, and z coordinate axes, respectively, then the cosine of the normal direction of the normal vector N at the corresponding point (x0, z0) is determined by the surface characteristics, such as the top and bottom surfaces, left and right surfaces, and front and back surfaces, as follows:

[0090]

[0091]

[0092]

[0093] Therefore, through calculation:

[0094] a) If cosβ=±1, it means that the direction of the spatial normal vector N makes an angle of 0 with the Y-axis. Which of the following satisfies this condition?

[0095]

[0096] The condition that satisfies the above is y = ±1, which represents the crest and trough lines.

[0097] b) If cosγ=0, it means that the direction of the spatial normal vector N makes an angle of 90° with the Z-axis. Taking the point (x0, z0) as the watershed, the spatial normal vector N on both sides of the Z-coordinate value of the Z-axis is symmetrically distributed and varies.

[0098] The conditions are:

[0099] That is, the variation law of y=f(x,z) that meets the above conditions is a sine curve, which has a high loosening force on the material.

[0100] like Figure 7-14 As shown, the size control screen plate 8 includes: a second screening hole 8-1, a separation hole 8-7, a separation curved surface 8-8, and a material discharge chute 8-9. The separation hole 8-7 and the material discharge chute 8-9, with the same diameter d2, are connected directly below the second screening hole 8-1 on the surface of the size control screen plate 8. The center distance between the second screening hole 8-1 and the separation hole 8-7 is h, where h is 2mm. The second screening hole 8-1 has a chamfer of 1×45°. The separation curved surface 8-8 and the material discharge chute 8-9 are connected and are located directly below and to the right of the separation hole 8-7, respectively. The tobacco scraps arrive at the second screening hole 8-1, the separation hole 8-7, and the separation surface 8-8 from right to left. The length dimension d2 of the stem is controlled and separated by the circumference of the separation hole 8-7 and the separation surface 8-8. Scraps smaller than d2 are discharged by the discharge chute 8-9, while those larger than d2 are ejected by the secondary vibrating chute (8-3) and then pass through the size control screen plate 8 into the next second screening hole 8-1, completing the control and separation of the stem length dimension d2, and so on. Due to the plasticity of tobacco, even if its natural length is greater than d2, it will most likely be discharged by the discharge chute 8-9.

[0101] The length L1 direction of the control size screen plate 8 is the directional movement direction of tobacco fragments, and the width B1 direction is perpendicular to the length L1 direction.

[0102] The sieve apertures (8-1) are distributed along length L1 according to a sinusoidal curve function, with the equation as follows: The wavelength is λ = 2π; the curved guide bar (7) is designed according to a sine curve, and the equation is: The wavelength is λ = 2π; let its wave height 2α = 20mm, and the wavelength λ = 125.6637mm.

[0103] In a preferred embodiment, d2 = 10 mm, and the diameter of the second sieve hole 8-1 is... The thickness of the control size sieve plate 8 is H = 11.5 mm, and nine second screening holes 8-1 are evenly distributed along one wavelength λ. The distance between two adjacent holes along wavelength λ is λ / 8 = 15.708 mm.

[0104] like Figure 10 , Figure 11 As shown, the distance from any point on the circular curve of the separation hole 8-7 to any point on the separation surface 8-8 is less than or equal to d2, and the condition for being equal to d2 is: an arc with a radius equal to d2, centered at any point on the circular curve of the separation hole 8-7, lies on the separation surface 8-8, which is a spatial surface of revolution.

[0105] The diameters of the second screening hole 8-1 and the separation hole 8-7 are Taking h as 2mm, or the thickness of the screening surface, and then chamfering it by 1×45° on the screening hole 8-1, will help improve the screening process. Taking two points AD on the circumference of the separation hole 8-7 as an example, the arc AB with point D as the center and radius R10mm is on the separation surface 8-7, and the arc BC with point A as the center and radius R10mm is also on the separation surface 8-8. Obviously, the line connecting point B and the center of the screening hole 8-1 is perpendicular to the screening surface and is the axis of rotation of the spatial rotation surface.

[0106] The material discharge groove 8-9 is an open through groove that passes through the circumference of the separation hole 8-7 and is tangent to the separation surface 8-8. The minimum distance from this tangent surface to the center of the separation hole 8-7 is x. x affects the accuracy or efficiency of separating and classifying the tags. The preferred range of x is: d2 = 10 mm, and the preferred range for x is: 0 ≤ x ≤ 2.071 mm.

[0107] In a preferred embodiment, x = 2.071 mm, and the central angle of arc BC is 15°. Then, it can be proven geometrically that... The material discharge chute 8-9 is designed as an open through chute with a width of 7.5mm.

[0108] The diameter d2 of the second screening hole 8-1 is calculated according to a sine curve function. The distribution of each second sieve hole 8-1 is such that the center of each second sieve hole 8-1 lies on a sine curve. Nine second sieve holes 8-1 are evenly distributed within a minimum period or a wavelength of λ = 125.6637 mm, and the distance between adjacent second sieve holes 8-1 in wavelength is λ / 8 = 15.709 mm.

[0109] Each of the second screening holes 8-1 on the sine curve is sequentially translated in the width B1 direction, and the translation distance is t, where t = 22 mm.

[0110] like Figure 11 As shown, L1 = 20λ = 2513.274mm. The number of second screening holes 8-1 distributed on L1 is: 8 × 20 + 1 = 161, which is the number distributed on a sine curve. The control size screen plate 8 is designed with 36 sine curves, so the number of second screening holes 8-1 is: 161 × 36 + 3 × 20 × 2 = 5916.

[0111] like Figure 12-14 As shown, the curved guide strip 7 is installed between the second screening holes 8-1 in the width B1 direction of the surface of the size control screen plate 8. The translation distance between adjacent curved guide strips 7 is t (t = 22 mm) or an integer multiple of t. The mounting holes 8-6 on the second screening holes 8-1 and the threaded holes 7-1 on the curved guide strip 7 are made in pairs. The size control screen plate 8 and the curved guide strip 7 are fixed with screws.

[0112] The stem tag size d2 can be inscribed in a diameter of 1. The spherical dimensions.

[0113] like Figure 7 As shown, a total of 11 curved guide strips 7 are designed, with an adjacent distance of 66mm (the translational distance). Figure 12-14 As shown, the curved guide bar 7 is designed with a width of 8mm and a height of 44mm, with rounded corners at the top. The threaded hole 7-1 on the curved guide bar 7 and the mounting hole 8-6 on the size control screen plate 8 are matched.

[0114] The curved guide strip 7 balances the flow rate of tobacco fragments, making the separation and classification more accurate. Therefore, the sinusoidal aperture and curved guide strip are superior.

[0115] Based on the range of the machine tool manufacturing workbench, the length L1 of the control-size sieve plate 8 is designed as an integer multiple of the wavelength λ = 125.6637 mm, and can be manufactured in sections.

[0116] The following integral analysis of the curve and surface of y = αsin(x) is given using differentials:

[0117] The line integral of y = αsin(x) with α ≤ 1 is Legendre's elliptic integral of the second kind, specifically expanded using Taylor series and followed by the Wallis definite integral formula. Organize the data and then list the calculations in an Excel spreadsheet. The following is the integral value for one period of 2π (one wavelength λ).

[0118] When y=si n(x): S1=7.63919.

[0119] When y = 1 / 2 × sin(x): S1 = 6.65917.

[0120] 1) The curved screen plate 4 has a wavelength of λ = 31.416 mm and a wave height of 2α = 10 mm. The definite integral over one wavelength λ in one period corresponds to a curve length of 38.196 mm. The length L of the curved screen plate 4 is designed to be 76λ, approximately 2387.667 mm, while the sine curve length is 2902.892 mm, a difference of 515.225 mm. The width B is designed to be 24λ, or 754.008 mm, while the sine curve length is 916.704 mm, a difference of 162.704 mm. It is evident that introducing a sine basis function to design the spatial curved surface y = f(x,z) significantly improves the screening area for tobacco fragments. This does not even consider the high efficiency of loosening and screening brought by the sine wave. If necessary, surface integrals can be introduced for more accurate calculation and evaluation of the screening area. For example, through the surface integral of the spatial curved surface S: y = f(x,z) = cos(x - sin z), the precise surface area of ​​S is:

[0121]

[0122] Here (x,z)∈D xz The partial differentials are calculated periodically without units. For example, x in the L direction: 76λ = 76 × 2π = 477.52168; y in the B direction: 24λ = 24 × 2π = 150.796, y [0, 2]. Therefore, the range of values ​​or integration length in this embodiment is: x [0, 2387.667], z [0, 754.008], y [0, 10]. Due to the symmetry and array nature of the sine curve surface, the above equation can be completed within 1 / 4 of a period.

[0123] 2) With the control size screen plate 8 having λ = 125.6637mm, wave height 2α = 20mm, and the definite integral of one wavelength λ corresponding to one period, i.e., the curve length value, is 133.183mm, the length of the control size screen plate (8) is designed to be 20λ, approximately 2513.274mm, and the sine curve length is 2663.660mm. The difference between the two is 150.386mm. This is the theoretical difference in the distance of the movement trajectory of tobacco fragments on the vibrating screen when using the sine curve and when not using the sine curve. Of course, the effect of the sine curve guiding the flow to achieve material equilibrium rate is not taken into account here.

[0124] In summary: Theoretically, the term "stem" is not quantitatively defined by geometric dimensions and physicochemical indicators, but rather based on its effects and characteristics. Therefore, the stem separation technology of this invention is based on application effects. In this invention, only hard stems with a diameter greater than [a certain value] are [specifically defined]. Furthermore, stems smaller than d2 cannot be separated. Therefore, according to cigarette manufacturing processes and quality requirements, the optimal diameter d1 value, such as 2–3.2 mm, and the optimal stem length d2 value, such as 6–10 mm, are crucial. Thus, this invention exhibits high loosening force, screening efficiency, and low breakage rate for tobacco scraps, and has a relatively accurate ability to separate stems from tobacco scraps, thereby improving the recovery rate and quality of tobacco.

[0125] Finally, at the three-dimensional curved hole C of the first screening hole on the curved surface of the curved screen plate 4, and at the edge of the outlet of the material chute 8-9 on the size control screen plate 8, manual trimming or chamfering is performed according to mechanical manufacturing standards to prevent the tobacco from being broken or clogged. While trimming or chamfering is a basic metalworking operation in mechanical manufacturing, the smoothness of the screening hole opening is crucial for vibrating screens, as it is a key area for tobacco clogging and tobacco oil deposition. Therefore, the trimming or chamfering process affects the performance of the vibrating screen.

[0126] like Figure 15 , 16 As shown, preferably, the discharge inclination angle of the stem discharge trough 10 is 6°, and the discharge inclination angle of the tobacco shred discharge trough 11 and the tobacco dust discharge trough 14 is 15°.

[0127] The above are merely preferred embodiments of the present invention and are illustrative rather than restrictive. The structure and connection methods of the components in the present invention can be varied, and any equivalent transformations and improvements made based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A device for separating tobacco scraps from stems and recycling tobacco shreds in the cigarette-making process, characterized in that, include: A primary vibrating screen (3) and a secondary vibrating screen (6); the primary vibrating screen (3) is provided with a curved screen plate (4), and the secondary vibrating screen (6) is provided with a size control screen plate (8); The upper surface of the curved sieve plate (4) is a spatial surface constructed from orthogonal sinusoidal basis functions. Let the length L direction of the material's directional movement be the x-axis, the width B direction perpendicular to the x-axis be the z-axis, and the direction perpendicular to the xz plane be the y-axis. The spatial surface is... Then, within the x-axis section at the origin of the coordinate system, the spatial surface... The equation of the curve on is: And spatial curved surface The coordinates of any point on the graph satisfy: and ,but The standard equation of a space surface is The curved sieve plate (4) has a plurality of first screening holes (4-1) formed on it. The first screening holes (4-1) are perpendicular to the xz plane on the curved surface in space. The cylindrical hole machined on the surface intersects with a continuous three-dimensional spatial curve C. The first screening hole (4-1) is on the spatial surface. The distribution method is to distribute the wavelengths at equal intervals on each wavelength λ. The upper surface of the size control screen plate (8) is provided with a plurality of second screening holes (8-1), and a separation hole (8-7) with the same diameter is connected directly below the second screening hole (8-1); the lower surface of the size control screen plate (8) forms a plurality of parallel and equally spaced material drop troughs (8-9); directly below the separation hole (8-7) is a separation space connected thereto, one side of the separation space is closed by a separation curved surface (8-8), and the other side is open and connected to the adjacent material drop trough (8-9); the length L1 direction of the size control screen plate (8) is the directional movement direction of the material, the width B1 direction is perpendicular to the length L1 direction, and the second screening holes (8-1) are distributed along a sine curve function along the length L1; the upper surface of the size control screen plate (8) is equipped with a plurality of curved guide strips (7) extending along the L1 direction, and the curved guide strips (7) are located between two adjacent second screening holes (8-1) in the width B1 direction.

2. The device for separating tobacco scraps from stems and recycling tobacco shreds in the cigarette-making process as described in claim 1, characterized in that, The diameter of the separation hole (8-7) is d2. An arc with a radius equal to d2 is formed with any point on the circumference of the separation hole (8-7) as the center. This arc is on the separation surface (8-8), which is a surface of revolution.

3. The device for separating tobacco scraps from stems and recycling tobacco shreds in the cigarette-making process as described in claim 2, characterized in that, The second sieve holes (8-1) are distributed along length L1 according to a sine curve function, with the center of each second sieve hole (8-1) lying on the sine curve. The equation is: The wavelength is λ=2π; the second sieve holes (8-1) on the sine curve in the width B1 direction are sequentially translated.

4. The device for separating tobacco scraps from stems and recycling tobacco shreds in the cigarette-making process as described in claim 3, characterized in that, The curved guide strip (7) is designed according to a sine curve, and the equation is: The wavelength is λ=2π.

5. The device for separating tobacco scraps from stems and recycling tobacco shreds in the cigarette-making process as described in claim 4, characterized in that, The diameter of the first screening hole (4-1) is d1, which is less than d2. The height h of the first screening hole (4-1) is not less than 3mm, and the minimum h value appears at the trough.

6. The device for separating tobacco scraps from stems and recycling tobacco shreds in the cigarette-making process as described in claim 5, characterized in that, The material discharge groove (8-9) is an open through groove that passes through the circumference of the separation hole (8-7) and is tangent to the separation surface (8-8). The minimum distance from the tangent surface of the material discharge groove (8-9) to the center of the separation hole (8-7) is x, and the range of x is: .

7. The device for separating tobacco scraps from stems and recycling tobacco shreds in the cigarette-making process as described in claim 6, characterized in that, The length L1 of the size control sieve plate (8) is designed as an integer multiple of the wavelength λ, and the designed length L1 of the size control sieve plate (8) is within 25 wavelengths λ.

8. The device for separating tobacco scraps from stems and recycling tobacco shreds in the cigarette-making process as described in claim 7, characterized in that, The three-dimensional space curve C opening of the first screening hole (4-1) on the curved surface of the curved screen plate (4) and the edge of the material discharge chute (8-9) outlet on the size control screen plate (8) are manually deburred or chamfered to prevent the tobacco from being broken or blocked.

9. The device for separating tobacco scraps from stems and recycling tobacco shreds in the cigarette-making process as described in claim 8, characterized in that, It also includes a hoist (2), a conveyor plate (5), a stem collection box (9), a stem discharge chute (10), a tobacco discharge chute (11), a tobacco collection box (12), a tobacco and stem collection cylinder (13), and a tobacco discharge chute (14); the hoist (2) is connected to the front end of the primary vibrating screen (3), and the end of the primary vibrating screen (3) and the front end of the secondary vibrating screen (6) are connected by the conveyor plate (5); the tobacco discharge chute (14) is set in the... Below the curved sieve plate (4), the tobacco stalk collection cylinder (13) is located below the outlet of the tobacco discharge trough (14); the tobacco shred discharge trough (11) is located below the size control sieve plate (8), and the tobacco shred collection box (12) is located below the outlet of the tobacco shred discharge trough (11); the end of the secondary vibrating sieve (6) is connected to the stalk discharge trough (10), and the stalk collection box (9) is located below the outlet of the stalk discharge trough (10).

10. A method for separating tobacco scraps from stems and recycling tobacco shreds in a cigarette-making process, characterized in that, The tobacco scrap separation and tobacco recycling device described in claim 9 is used in the cigarette making process. Tobacco scraps are fed into the primary vibrating screen (3) via an elevator (2). After passing through the curved screen plate (4) and the cylindrical first screening hole (4-1), the hard, piercing stems are captured by the three-dimensional curved hole C on the curved surface. Tobacco dust and stems with a diameter smaller than d1 are screened out and fed into the tobacco dust and stem collection cylinder (13) through the tobacco dust discharge chute (14). The remaining material is fed into the secondary vibrating screen (6) via a screening conveyor. The material is then fed into the secondary vibrating screen (6) via a curved guide bar (7), a size control screen plate (8), and the second... Screening holes (8-1), separation holes (8-7), separation surfaces (8-8) and discharge troughs (8-9) screen out hard stems with poor plasticity and a length dimension greater than d2, and input them into stem collection boxes (9) through stem discharge troughs (10). Plastic and flexible tobacco shreds are sequentially passed through the second screening holes (8-1), separation holes (8-7), separation surfaces (8-8) and discharge troughs (8-9), and then input into tobacco collection boxes (12) through tobacco discharge troughs (11).

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