A screening device and method for thin filaments

Abstract

This invention discloses a screening device and method for thin filaments, comprising a first vibrating screen, a first vibrating screen plate, a first discharge chute, a second vibrating screen, a second vibrating screen plate, a second discharge chute, and a third discharge chute; the first and second vibrating screens are arranged sequentially along a conveying direction; the first vibrating screen plate is disposed within the first vibrating screen, and the first vibrating screen plate is a vibrating screen plate based on a sinusoidal basis function, with the material conveying direction on the first vibrating screen plate perpendicular to the extension direction of the trough line of the curved surface of the first vibrating screen plate; the first conveying plate has multiple first screening holes; the second vibrating screen plate is disposed within the second vibrating screen, and the second vibrating screen plate is located below the end of the first vibrating screen plate, the second vibrating screen plate is a vibrating screen plate based on a sinusoidal basis function, and the material conveying direction on the second vibrating screen plate is parallel to the extension direction of the trough line of the curved surface of the second vibrating screen plate; the second conveying plate has multiple second screening holes. The screening device of this application has high screening efficiency and good screening effect.

Description

Technical Field

[0001] This application relates to the technical field of tobacco processing, and more specifically, to a screening device and method for tobacco filaments. Background Technology

[0002] New tobacco products—thin sheet tobacco—are made by cutting tobacco sheets into thin sheets with a width of 0.8mm, then moistening, adding ingredients, drying, and blending them into flue-cured tobacco shreds. After flavoring, they are rolled into cigarettes. They have the advantages of reducing tobacco leaf usage, tar content, and improving cigarette quality, so the application of thin sheet tobacco is becoming more and more widespread. Tobacco sheets refer to irregular "paper sheets" with a thickness of about 0.2 mm, produced from tobacco scraps, or with geometric dimensions similar to "medium-sized tobacco" produced in a re-drying workshop, or in "blocks" ranging from 50 mm to 100 mm square. Their physicochemical properties are easy to control, so tobacco sheets have higher toughness and mechanical strength than natural tobacco sheets. This also results in the thin sheets cut from tobacco sheets having a certain degree of stickiness and entanglement. In other words, the thin sheets are not as loose as flue-cured tobacco. Furthermore, there are often many thin sheets of various sizes mixed in with the thin sheets due to uncut tobacco sheets, such as 8 mm square, 10 mm square, or even 20 mm or larger square. These thin sheets of various sizes need to be removed according to the requirements of tobacco processing and cigarette making. Because the flakes are very thin and have high adhesiveness, entanglement, and toughness, using ordinary screens, such as flat screens or wire mesh screens, often leads to clogging or clumping of the flakes, making it difficult to separate flakes of different sizes from the flakes. Existing technologies employ multi-stage vibrating screens, increase the length of the screening line, improve the physical properties of the vibrating trough (such as amplitude and frequency), or enlarge the size of the screening holes, but the results are not significant. Summary of the Invention

[0003] To address at least one aspect of the aforementioned problems, the present invention provides a screening device for thin filaments, comprising a first vibrating screen, a first vibrating screen plate, a first discharge chute, a second vibrating screen, a second vibrating screen plate, a second discharge chute, and a third discharge chute; the first vibrating screen and the second vibrating screen are arranged sequentially along a conveying direction; the first vibrating screen plate is disposed within the first vibrating screen; the first vibrating screen plate includes a first transmission plate, the upper surface of the first transmission plate is provided with a first transmission surface, the first transmission surface is a curved surface formed by a first generatrix moving along a first trajectory, the first generatrix is ​​a cosine curve in a vertical plane, the tangents of the first generatrix at the crests and troughs are parallel to the length direction of the first transmission plate, the first trajectory is a sine curve in a horizontal plane, the tangents of the first trajectory at the crests and troughs are parallel to the width direction of the first transmission plate; the length direction of the first vibrating screen plate is the same as the conveying direction, such that the extension direction of the trough line of the first vibrating screen plate is perpendicular to the conveying direction; a plurality of first screening holes are opened on the first transmission plate; the second vibrating screen plate is disposed within the second vibrating screen. Inside the vibrating screen, a second vibrating screen plate is positioned below the end of the first vibrating screen plate. The second vibrating screen plate includes a second transmission plate, the upper surface of which is configured as a second transmission surface. The second transmission surface is a curved surface formed by a second generatrix moving along a second trajectory. The second generatrix is ​​a cosine curve in a vertical plane, and the tangents of the second generatrix at its crests and troughs are parallel to the width direction of the second transmission plate. The second trajectory is a sine curve in a horizontal plane, and the tangents of the second trajectory at its crests and troughs are parallel to the length direction of the second transmission plate. The length direction of the second vibrating screen plate is the same as the conveying direction, such that the extension direction of the trough line of the second vibrating screen plate is parallel to the conveying direction. Multiple second screening holes are provided on the second transmission plate. A first discharge chute is connected to the end of the first vibrating screen and is used to transmit the thin sheet filaments that pass through the first vibrating screen plate. A second discharge chute is connected to the end of the second vibrating screen and is used to transmit the thin sheet filaments that pass through the second vibrating screen plate. A third discharge chute is connected to the end of the second vibrating screen plate and is used to transmit the thin sheet filaments that do not pass through the second vibrating screen plate.

[0004] Through the above technical solution, a two-stage screening device based on a sinusoidal basis function vibrating screen plate is used for continuous screening. The conveying direction of the mixture on the first vibrating screen plate is designed to be perpendicular to the extension direction of the trough line of the first vibrating screen plate, and the conveying direction of the mixture on the second vibrating screen plate is designed to be parallel to the extension direction of the trough line of the second vibrating screen plate. For the first screening, due to the large material flow rate on the first vibrating screen plate, a vibrating screen plate with high looseness and high screening rate is required. This is achieved by designing the conveying direction of the material on the first vibrating screen plate to be perpendicular to the extension direction of the trough line of the first vibrating screen plate. The perpendicular extension direction facilitates optimal loosening of the material by utilizing the crests and troughs on the curved surface of the first vibrating screen plate. It also facilitates the capture of thin tobacco flakes by the first screening holes and the separation of flakes larger than the size of the first screening holes. For the second screening, since the flow rate of the mixture decreases after the first screening and already exhibits good loosening, designing the material conveying direction on the second vibrating screen plate parallel to the extension direction of the troughs of the second vibrating screen plate, while resulting in a weaker loosening effect than the first vibrating screen plate, promotes uniform material distribution and reduces breakage. Therefore, the screening device of this application has high screening efficiency and good screening effect, which is beneficial for improving the purity of thin tobacco flakes.

[0005] Because thin filaments are fine and highly resilient, creating the first or second screening holes on the crest line or surface of the first or second vibrating screen plate would result in sharp edges at the holes, easily causing the filaments to break or become clogged. Even using deburring techniques from the machinery manufacturing industry cannot easily solve the problem of material clogging in the first or second screening holes. Preferably, the first screening hole is located on the trough line of the first vibrating screen plate, and the second screening hole is located on the trough line of the second vibrating screen plate. Through this technical solution, creating the first or second screening holes on the trough line of the first or second vibrating screen plate is where the hole edges are least sharp. Furthermore, because the sinusoidal surface on both sides of the trough smoothly transitions to the crest, and the crest has a high material loosening effect, designing screening holes on the trough line yields the best screening effect. Therefore, choosing to create screening holes on the trough line helps improve the screening effect and reduce the breakage rate.

[0006] Preferably, p first screening holes are opened within each wavelength of the trough line of the first vibrating screen plate using an average interpolation method, and q second screening holes are opened within each wavelength of the trough line of the second vibrating screen plate using an average interpolation method, where p and q are both odd numbers.

[0007] Since the material flow rate on the first vibrating screen plate is greater than that on the second vibrating screen plate, preferably, the size of the first screening hole is less than or equal to the size of the second screening hole, so as to balance the material screening on the two vibrating screen plates, control the screening amount on the two vibrating screen plates, and help improve the screening accuracy of each vibrating screen plate.

[0008] Preferably, both the first sieve hole and the second sieve hole are round holes, the diameter of the first sieve hole is less than or equal to the diameter of the second sieve hole, and the diameter of the second sieve hole is in the range of 5 to 10 mm.

[0009] Larger amplitudes offer better "penetration" to materials, but can prevent the construction of continuous spatial surfaces or hinder mechanical manufacturing. Smaller amplitudes, on the other hand, can reduce the loose conveying performance of the superimposed spatial surfaces. Preferably, the amplitude range of both the first and second busbars is 1 to 1.5.

[0010] Preferably, the lengths of the first and second vibrating screen plates range from 39λ to 40λ, and the widths of the first and second vibrating screen plates are both 24λ, where λ is the wavelength of the curved surface of the first or second vibrating screen plate. By utilizing the golden ratio in the design of the vibrating screen plates, the above technical solution contributes to their aesthetically pleasing appearance.

[0011] Preferably, the first vibrating screen plate further includes a first transition plate, which is a flat plate, flush with the first transmission plate, and fixedly connected to the end of the first transmission plate; the second vibrating screen plate further includes a second transition plate, which is a flat plate, flush with the second transmission plate, and fixedly connected to the end of the second transmission plate.

[0012] Preferably, the first vibrating screen plate further includes two first side guards and one first end guard. The top of the first side guard and the top of the first end guard are both higher than the crest of the curved surface of the first transmission plate. The two first side guards are fixedly connected to both sides of the first vibrating screen plate, and the first end guard is fixedly connected to the beginning of the first vibrating screen plate. The two ends of the first end guard are fixedly connected to the ends of the two first side guards. The second vibrating screen plate further includes two second side guards. The top of the second side guard is higher than the crest of the curved surface of the second transmission plate. The two second side guards are fixedly connected to both sides of the second vibrating screen plate.

[0013] This application also provides a method for screening sheet filaments, comprising the following steps:

[0014] Step 1: Using a first vibrating screen plate based on a sinusoidal basis function, the first mixture of thin sheet filaments and thin sheets is conveyed along the direction perpendicular to the trough line of the first vibrating screen plate to perform a first screening into thin sheet filaments and a second mixture;

[0015] Step 2: Using a second vibrating screen plate based on a sinusoidal basis function, the second mixture generated in Step 1 is conveyed along the direction parallel to the extension direction of the trough line of the second vibrating screen plate for secondary screening into thin filaments and thin sheets.

[0016] The sieving device and method for thin filaments of the present invention have the following beneficial effects:

[0017] By designing a two-stage screening device and method for screening thin filaments, for the first-stage screening, due to the entanglement of the filaments and the large material flow rate on the first vibrating screen plate, a vibrating screen plate with high loosening and screening rates is required. A vibrating screen plate based on a sinusoidal basis function is used as the first vibrating screen plate, and the material conveying direction on it is designed to be perpendicular to the extension direction of the troughs on its curved surface. This facilitates optimal loosening of the crests and troughs on the curved surface of the first vibrating screen plate, and also facilitates the capture of filaments by the first screening apertures and the separation of filaments of various sizes larger than the first screening aperture size. For the second-stage screening, since the flow rate of the mixture decreases after the first screening, and the material has already been... This method exhibits good loosening effect. It employs a sine-based vibrating screen plate as the second vibrating screen plate, with the material conveying direction designed to be parallel to the extension direction of the troughs on its curved surface. Although its loosening effect is weaker than that of the first vibrating screen plate, it is beneficial for the uniform distribution of material and reduces the breakage rate. By opening multiple first screening holes and multiple second screening holes only on the troughs of the first and second vibrating screen plates respectively, the edges of the holes are not sharp, which helps reduce the occurrence of breakage or clogging of the thin tobacco sheets. Furthermore, because the sinusoidal curved surface on both sides of the trough smoothly transitions to the crest, and the crest has a high loosening effect on the material, designing screening holes on the troughs yields the best screening effect. Therefore, the apparatus and method of this application have the characteristics of high screening efficiency and good screening effect, which is beneficial for improving the purity of thin tobacco sheets. Attached Figure Description

[0018] To better understand the above and other objects, features, advantages, and functions of the present invention, reference can be made to the embodiments shown in the accompanying drawings. The same reference numerals in the drawings refer to the same parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate preferred embodiments of the invention and do not limit the scope of the invention in any way; the parts in the drawings are not drawn to scale.

[0019] Figure 1 A schematic diagram of a sieving device for sheet filaments according to an embodiment of the present invention is shown;

[0020] Figure 2 A partial structural schematic diagram of the first vibrating screen plate of a sieving device for thin filaments according to an embodiment of the present invention is shown;

[0021] Figure 3 A partial top view of the first vibrating screen plate of a sieving device for thin filaments according to an embodiment of the present invention is shown;

[0022] Figure 4 A partial top view of the second vibrating screen plate of a sieving device for thin filaments according to an embodiment of the present invention is shown;

[0023] Figure 5 An analytical diagram illustrating the selection of the sieving hole position in a sieving device for thin filaments according to an embodiment of the present invention is shown.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1. Feed chute; 2. First vibrating screen; 3. First vibrating screen plate; 31. First transmission plate; 311. First screening hole; 32. First transition plate; 33. First side guard plate; 34. First end guard plate; 4. First discharge chute; 5. First collection box; 6. Second vibrating screen; 7. Second vibrating screen plate; 71. Second transmission plate; 711. Second screening hole; 72. Second transition plate; 73. Second side guard plate; 74. Second end guard plate; 8. Second discharge chute; 9. Second collection box; 10. Third discharge chute; 11. Third collection box. Detailed Implementation

[0026] The exemplary embodiments of this disclosure are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this disclosure. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0027] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0028] To at least partially address one or more of the aforementioned problems and other potential issues, one embodiment of this disclosure provides a sieving device for thin filaments, comprising a first vibrating screen 2, a first vibrating screen plate 3, a first discharge chute 4, a second vibrating screen 6, a second vibrating screen plate 7, a second discharge chute 8, and a third discharge chute 10; the first vibrating screen 2 and the second vibrating screen 6 are arranged sequentially along a conveying direction; the first vibrating screen plate 3 is disposed within the first vibrating screen 2; the first vibrating screen plate 3 includes a first transmission plate 31, the upper surface of which is provided with a first transmission surface. The first transmission surface is a curved surface formed by the movement of the first generatrix along the first trajectory. The first generatrix is ​​a cosine curve in a vertical plane, and the tangents of the first generatrix at the crests and troughs are parallel to the length direction of the first transmission plate 31. The first trajectory is a sine curve in a horizontal plane, and the tangents of the first trajectory at the crests and troughs are parallel to the width direction of the first transmission plate 31. The length direction of the first vibrating screen plate 3 is the same as the transmission direction, so that the extension direction of the trough line of the first vibrating screen plate 3 is perpendicular to the transmission direction. The first transmission plate 31 has a plurality of first screening holes 311. The second vibrating screen plate 7 is disposed within the second vibrating screen 6, and is located below the end of the first vibrating screen plate 3. The second vibrating screen plate 7 includes a second transmission plate 71, the upper surface of which is configured as a second transmission surface. The second transmission surface is a curved surface formed by the movement of a second generatrix along a second trajectory. The second generatrix is ​​a cosine curve in a vertical plane, and the tangents of the second generatrix at the crests and troughs are parallel to the width direction of the second transmission plate 71. The second trajectory is a sine curve in a horizontal plane, and the tangents of the second trajectory at the crests and troughs are parallel to the width direction of the second transmission plate 71. The length direction of the second vibrating screen plate 7 is the same as the conveying direction, so that the extension direction of the trough line of the second vibrating screen plate 7 is parallel to the conveying direction; a plurality of second screening holes 711 are opened on the second transmission plate 71; the first discharge chute 4 is connected to the end of the first vibrating screen 2 and is used to transmit the thin sheet wires that pass through the first vibrating screen plate 3; the second discharge chute 8 is connected to the end of the second vibrating screen 6 and is used to transmit the thin sheet wires that pass through the second vibrating screen plate 7; the third discharge chute 10 is connected to the end of the second vibrating screen plate 7 and is used to transmit the thin sheet that does not pass through the second vibrating screen plate 7.

[0029] Specifically, such as Figures 1 to 5As shown, the first vibrating screen 2 and the second vibrating screen 6 are both horizontally arranged and sequentially arranged along the conveying direction. In this embodiment, the conveying direction is the x-direction. The first vibrating screen plate 3 and the second vibrating screen plate 7 are respectively arranged inside the first vibrating screen 2 and the second vibrating screen 6, and the second vibrating screen plate 7 is arranged below the end of the first vibrating screen plate 3. Preferably, the beginning of the second vibrating screen plate 7 is arranged below the end of the first vibrating screen plate 3. A feeding chute is arranged above the beginning of the first vibrating screen plate 3 for conveying a mixture of thin filaments and thin sheets. The first discharge chute 4 is connected to the end of the first vibrating screen 2 for conveying materials passing through the first vibrating screen 2. The first discharge chute 4 has a first collection box 5 at its outlet end for holding the thin filaments that pass through the first vibrating screen plate 3; the second discharge chute 8 is connected to the end of the second vibrating screen 6 for transmitting the thin filaments that pass through the second vibrating screen plate 7; the second discharge chute 8 has a second collection box 9 at its outlet end for holding the thin filaments that pass through the second vibrating screen plate 7; the third discharge chute 10 is connected to the end of the second vibrating screen plate 7 for transmitting the thin filaments that do not pass through the second vibrating screen plate 7; the third discharge chute 10 has a third collection box 11 at its outlet end for holding the thin filaments that do not pass through the second vibrating screen plate 7.

[0030] like Figures 1 to 3 As shown, the first vibrating screen plate 3 includes a first transmission plate 31. The length and width directions of the first transmission plate 31 are the same as the length and width directions of the first vibrating screen plate 3. A first transmission surface is provided on the upper surface of the first transmission plate 31. The first transmission surface is a curved surface formed by the movement of a first generatrix along a first trajectory. The first generatrix is ​​a cosine curve in a vertical plane. The tangents of the first generatrix at the crests and troughs are parallel to the length direction of the first transmission plate 31. The first trajectory is a sine curve in a horizontal plane. The tangents of the first trajectory at the crests and troughs are parallel to the width direction of the first transmission plate 31. The length direction of the first vibrating screen plate 3 is the same as the transmission direction, so that the extension direction of the trough line of the first vibrating screen plate 3 is perpendicular to the transmission direction.

[0031] Specifically, the length and width directions of the first conveying plate are perpendicular to each other. In this embodiment, the length direction of the first conveying plate is the x-direction, the width direction is the y-direction, and the thickness direction is the z-direction. Therefore, the surface equation of the first transmission surface is: z = f(x,y). The first generatrix corresponds to a cosine curve in the xoz plane, expressed as: z = α·cos(x), where α is the amplitude. Preferably, the amplitude range of the first generatrix is ​​1 to 1.5. In this embodiment, α is 1.1. The first trajectory corresponds to a sine curve in the xoy plane, expressed as: x = sin(y). The crest line of the first trajectory is expressed as: x = sin(y) + 2mπ, and the trough line of the first trajectory is expressed as: x = sin(y) + (2m-1)π, where m is a positive integer. Therefore, for the first transmission surface, its crest line equation is expressed as: The equation for the trough line is expressed as: λ is the wavelength of the curved surface of the first vibrating screen plate 3.

[0032] The first transmission plate 31 has a plurality of first screening holes 311, the inner wall of the first screening holes 311 being perpendicular to the horizontal plane. The first screening holes 311 can be any one of round holes, elliptical holes, or oblong holes; preferably, the first screening holes 311 are located on the trough lines of the first vibrating screen plate 3, such as... Figure 5 As shown, creating the first screening holes 311 on the crest line and wave surface of the first vibrating screen plate 3 results in sharp, acute angles at the edges of the first screening holes 311, as indicated by point C in the crest holes and wave face in the figure. This easily causes the thin sheet fibers to break or become clogged. Even with deburring and barbing techniques used in the machinery manufacturing industry, it is difficult to solve the material clogging problem of the first screening holes 311 or the second screening holes 711. However, as indicated by point C in the trough holes in the figure, the edges are not sharp, and because the sinusoidal surface on both sides of the trough smoothly changes to the crest, and the crest has a higher material loosening effect, designing screening holes on the trough has the best screening effect. Therefore, choosing to open screening holes on the trough line helps to improve the screening effect and reduce the breakage rate. More preferably, multiple first screening holes 311 are opened p times within each wavelength on the trough line of the first vibrating screen plate 3 using an average interpolation method, where p is an odd number. In this embodiment, p is 5. Then the center coordinates of each first screening hole 311 are: n is a positive integer representing the index in the y-axis direction, and m represents the index of the trough line in the x-axis direction. In this embodiment, the wavelength λ = 31.4159 mm. When n = 1 and m = 1, x = 0 and y = 0, indicating that the first screening hole 311 is drilled at the origin. When n = 17 and m = 18, m = 18 indicates that the hole is drilled on the 18th trough line from the origin according to a sine curve, and the position index is n = 17. Substituting into the above equations, its coordinate value is (549.778, 125.664). The calculation of other index parameters is similar.

[0033] In some embodiments, the first vibrating screen plate 3 further includes a first transition plate 32, which is a flat plate. The first transition plate 32 is flush with the first transmission plate 31 and is fixedly connected to the end of the first transmission plate 31. The first vibrating screen plate 3 also includes two first side guard plates 33 and one first end guard plate 34. The top ends of the first side guard plates 33 and the first end guard plate 34 are both higher than the crests of the curved surface of the first transmission plate 31. The two first side guard plates 33 are fixedly connected to both sides of the first vibrating screen plate 3, and the first end guard plate 34 is fixedly connected to the first vibrating screen plate 3. At the beginning, the two ends of the first end guard plate 34 are fixedly connected to the ends of the two first side guard plates 33 respectively, and the top end of the first end guard plate 34 is connected to the outlet end of the feed trough 1; preferably, the length of the first vibrating screen plate 3 is 39λ~40λ, the width of the first vibrating screen plate 3 is 24λ. In this embodiment, the length of the first vibrating screen plate 3 is 39λ. Substituting the value of λ, the length of the first vibrating screen plate 3 is 1225.220mm, the width of the first vibrating screen plate 3 is 754.008mm, and the thickness of the first vibrating screen plate 3 is designed to be 12.5mm.

[0034] like Figure 1 and Figure 4 As shown, the second vibrating screen plate 7 includes a second transmission plate 71. The length and width directions of the second transmission plate 71 are the same as the length and width directions of the second vibrating screen plate 7. The upper surface of the second transmission plate 71 is set as a second transmission surface. The second transmission surface is a curved surface formed by the movement of a second generatrix along a second trajectory. The second generatrix is ​​a cosine curve in a vertical plane. The tangents of the second generatrix at the crests and troughs are parallel to the width direction of the second transmission plate 71. The second trajectory is a sine curve in a horizontal plane. The tangents of the second trajectory at the crests and troughs are parallel to the length direction of the second transmission plate 71. The length direction of the second vibrating screen plate 7 is the same as the transmission direction, so that the extension direction of the trough line of the second vibrating screen plate 7 is parallel to the transmission direction.

[0035] Specifically, the length and width directions of the second conveying plate are perpendicular to each other. In this embodiment, the length direction of the second conveying plate is the x-direction, the width direction is the y-direction, and the thickness direction is the z-direction. Therefore, the surface equation of the second transmission surface is: z = f(x,y). The second generatrix corresponds to a cosine curve in the yoz plane, expressed as: z = α·cos(y), where α is the amplitude. Preferably, the amplitude range of the second generatrix is ​​1 to 1.5. In this embodiment, α is 1. The second trajectory corresponds to a sine curve in the xoy plane, expressed as: y = sin(x). The crest line of the second trajectory is expressed as: y = sin(x) + 2mπ, and the trough line of the second trajectory is expressed as: y = sin(x) + (2m-1)π, where m is a positive integer. Therefore, for the second transmission surface, its crest line equation is expressed as: The equation for the trough line is expressed as: λ is the wavelength of the curved surface of the second vibrating screen plate 7.

[0036] The second transmission plate 71 has multiple second screening holes 711. The inner wall of each second screening hole 711 is perpendicular to the horizontal plane. Each second screening hole 711 can be any one of a round hole, an elliptical hole, or a waist-shaped hole. Preferably, the size of the second screening hole 711 is equal to or greater than the size of the first screening hole 311. More preferably, both the first screening hole 311 and the second screening hole 711 are round holes, with the diameter of the first screening hole 311 being less than or equal to the diameter of the second screening hole 711. The diameter of the second screening hole 711 ranges from 5 to 10 mm. Preferably, the second screening holes 711 are located on the trough line of the second vibrating screen plate 7, for the same reason as the first screening hole 311 is located on the trough line of the first vibrating screen plate 3. More preferably, the multiple second screening holes 711 are opened q times within each wavelength of the trough line of the second vibrating screen plate 7 using an average interpolation method, where q is an odd number. In this embodiment, q is 5. Therefore, the center coordinates of each second screening hole 711 are: n is a positive integer representing the index in the x-axis direction, and m represents the index of the trough line in the y-axis direction. In this embodiment, the wavelength λ = 31.4159 mm. When n = 1 and m = 1, x = 0 and y = 0, which means that the second screening hole 711 is drilled at the origin. Similarly, other index parameters can be substituted into the above equations for calculation, and so on.

[0037] In some embodiments, the second vibrating screen plate 7 further includes a second transition plate 72, which is a flat plate. The second transition plate 72 is flush with the second transmission plate 71 and is fixedly connected to the end of the second transmission plate 71. The second vibrating screen plate 7 also includes two second side guard plates 73 and one second end guard plate 74. The top ends of the second side guard plates 73 and the second end guard plate 74 are both higher than the crests of the curved surface of the second transmission plate 71. The two second side guard plates 73 are fixedly connected to both sides of the second vibrating screen plate 7, and the second end guard plate 74 is fixedly connected to the second vibrating screen plate 7. At the beginning of the first vibrating screen plate 7, the two ends of the second end guard plate 74 are fixedly connected to the ends of the two second side guard plates 73 respectively, and the top end of the second end guard plate 74 is connected to the tail end of the first vibrating screen plate 3. Preferably, the length of the second vibrating screen plate 7 is 39λ to 40λ, and the width of the second vibrating screen plate 7 is 24λ. In this embodiment, the length of the second vibrating screen plate 7 is 40λ. Substituting the value of λ, the length of the second vibrating screen plate 7 is 1256.680mm, the width of the second vibrating screen plate 7 is 754.008mm, and the thickness of the second vibrating screen plate 7 is designed to be 11.5mm.

[0038] This application also provides a method for screening sheet filaments, comprising the following steps:

[0039] Step 1: Using a first vibrating screen plate 3 based on a sinusoidal basis function, the first mixture of thin sheet filaments and thin sheets is conveyed along the direction perpendicular to the trough line of the first vibrating screen plate 3 to perform a first screening into thin sheet filaments and a second mixture;

[0040] Step 2: Using a second vibrating screen plate 7 based on a sinusoidal basis function, the second mixture generated in step 1 is conveyed along the direction parallel to the extension direction of the trough line of the second vibrating screen plate 7 for secondary screening into thin filaments and thin sheets.

[0041] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand this document.

Claims

1. A sieving device for thin filaments, characterized in that: It includes a first vibrating screen (2), a first vibrating screen plate (3), a first discharge chute (4), a second vibrating screen (6), a second vibrating screen plate (7), a second discharge chute (8), and a third discharge chute (10); The first vibrating screen (2) and the second vibrating screen (6) are arranged sequentially along the conveying direction; The first vibrating screen plate (3) is disposed inside the first vibrating screen (2); the first vibrating screen plate (3) includes a first transmission plate (31), the upper surface of the first transmission plate (31) is provided with a first transmission surface, the first transmission surface is a curved surface formed by the movement of the first generatrix along the first trajectory, the first generatrix is ​​a cosine curve in the vertical plane, the tangent of the first generatrix at the crest and trough is parallel to the length direction of the first transmission plate (31), the first trajectory is a sine curve in the horizontal plane, the tangent of the first trajectory at the crest and trough is parallel to the width direction of the first transmission plate (31); the length direction of the first vibrating screen plate (3) is the same as the transmission direction, so that the extension direction of the trough line of the first vibrating screen plate (3) is perpendicular to the transmission direction; a plurality of first screening holes (311) are opened on the first transmission plate (31), the first screening holes (311) are opened on the trough line of the first vibrating screen plate (3); The second vibrating screen plate (7) is disposed inside the second vibrating screen (6), and the second vibrating screen plate (7) is disposed below the end of the first vibrating screen plate (3); the second vibrating screen plate (7) includes a second transmission plate (71), the upper surface of the second transmission plate (71) is configured as a second transmission surface, the second transmission surface is a curved surface formed by the movement of the second generatrix along the second trajectory, the second generatrix is ​​a cosine curve in the vertical plane, the tangents of the second generatrix at the crests and troughs are parallel to the width direction of the second transmission plate (71), the second trajectory is a sine curve in the horizontal plane, the tangents of the second trajectory at the crests and troughs are parallel to the length direction of the second transmission plate (71); the length direction of the second vibrating screen plate (7) is the same as the conveying direction, so that the extension direction of the trough line of the second vibrating screen plate (7) is parallel to the conveying direction; a plurality of second screening holes (711) are opened on the second transmission plate (71), and the second screening holes (711) are opened on the trough line of the second vibrating screen plate (7); The first discharge chute (4) is connected to the end of the first vibrating screen (2) and is used to transmit the thin filaments through the first vibrating screen plate (3); The second discharge chute (8) is connected to the end of the second vibrating screen (6) and is used to transmit the thin filaments through the second vibrating screen plate (7); The third discharge chute (10) is connected to the end of the second vibrating screen plate (7) and is used to transfer the sheet that has not passed through the second vibrating screen plate (7).

2. The sieving device for thin filaments according to claim 1, characterized in that: Multiple first screening holes (311) are opened p times within each wavelength of the trough line of the first vibrating screen plate (3) using the average interpolation method, and multiple second screening holes (711) are opened q times within each wavelength of the trough line of the second vibrating screen plate (7) using the average interpolation method, where p and q are both odd numbers.

3. The sieving device for thin filaments according to claim 1, characterized in that: The size of the first screening hole (311) is less than or equal to the size of the second screening hole (711).

4. The sieving device for thin filaments according to claim 3, characterized in that: Both the first sieve hole (311) and the second sieve hole (711) are round holes. The diameter of the first sieve hole (311) is less than or equal to the diameter of the second sieve hole (711), and the diameter of the second sieve hole (711) ranges from 5 to 10 mm.

5. The sieving device for thin filaments according to claim 1, characterized in that: The amplitude range of the first busbar and the amplitude range of the second busbar are both 1 to 1.

5.

6. The sieving device for thin filaments according to claim 1, characterized in that: The length of the first vibrating screen plate (3) and the length of the second vibrating screen plate (7) are in the range of 39. ~40 The width of the first vibrating screen plate (3) and the width of the second vibrating screen plate (7) are 24. , The wavelength is the surface of the first vibrating screen plate (3) or the surface of the second vibrating screen plate (7).

7. The sieving device for thin filaments according to claim 1, characterized in that: The first vibrating screen plate (3) further includes a first transition plate (32), which is a flat plate. The first transition plate (32) is flush with the first transmission plate (31) and is fixedly connected to the end of the first transmission plate (31). The second vibrating screen plate (7) further includes a second transition plate (72), which is a flat plate. The second transition plate (72) is flush with the second transmission plate (71) and is fixedly connected to the end of the second transmission plate (71).

8. The sieving device for thin filaments according to claim 1, characterized in that: The first vibrating screen plate (3) also includes two first side guard plates (33) and one first end guard plate (34). The top of the first side guard plate (33) and the top of the first end guard plate (34) are both higher than the peak of the curved surface of the first transmission plate (31). The two first side guard plates (33) are fixedly connected to the two sides of the first vibrating screen plate (3) respectively. The first end guard plate (34) is fixedly connected to the beginning of the first vibrating screen plate (3). The two ends of the first end guard plate (34) are fixedly connected to the ends of the two first side guard plates (33) respectively. The second vibrating screen plate (7) also includes two second side guard plates (73). The top of the second side guard plate (73) is higher than the peak of the curved surface of the second transmission plate (71). The two second side guard plates (73) are fixedly connected to the two sides of the second vibrating screen plate (7) respectively.

9. A method for screening thin filaments, applied to the screening device for thin filaments as described in any one of claims 1 to 8, characterized in that: Includes the following steps: Step 1: Using a first vibrating screen plate (3) based on a sinusoidal basis function, the first mixture of thin sheet filaments and thin sheets is conveyed along the direction perpendicular to the trough line of the first vibrating screen plate (3) to perform a first screening into thin sheet filaments and a second mixture; Step 2: Using a second vibrating screen plate (7) based on a sinusoidal basis function, the second mixture generated in step 1 is conveyed along the direction parallel to the extension direction of the trough line of the second vibrating screen plate (7) for secondary screening into thin filaments and thin sheets.

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