AEROSOL GENERATING ARTICLES

Abstract

A filter part (1) for use in an aerosol generating article and a method of manufacturing the filter part (1). The filter part (1) includes an aerosol permeable core (11) surrounded by a sleeve (12). The sleeve (12) is formed of linear, axially oriented fibres and the core (11) is formed of expanded, randomly oriented fibres. The method includes forming two or more strips (2a, 2b) into segments surrounding a conveying path, bringing the segments together into a sleeve former (7) to form the sleeve (12) and introducing loose fibres (52) between the segments upstream of the sleeve former (7) such that they are drawn therein in a random orientation and compressed between the segments as they are brought together to form a filter rod (8) with an aerosol permeable core (11) within the sleeve (12). The filter rod (8) is then cut to form the filter part (1).

Claims

1. An aerosol permeation element for use in an aerosol generating article, the aerosol permeation element comprising an aerosol permeable core surrounded by a sleeve, wherein the sleeve comprises linear, axially oriented fibres and the core comprises expanded, randomly oriented fibres, wherein the sleeve comprises two or more longitudinal segments formed from the same tow and the tow material of the longitudinal segments is bonded together at least along longitudinal edges of the segments to form an integral sleeve.

2. Aerosol permeation element according to claim 1, wherein the core comprises fibres formed from the same tow as the two or more longitudinal segments.

3. Aerosol permeation element according to claim 1, wherein the tow, from which the sleeve or core or both the sleeve and core, is formed, comprises cellulose acetate or poly lactic acid fibres.

4. Aerosol permeation element according to claim 1, wherein the sleeve comprises a wall thickness of between 0.5 millimetres and 3 millimetres.

5. Aerosol permeation element according to claim 1, wherein the core comprises a diameter of between 2 millimetres and 8 millimetres.

6. An aerosol generating article comprising an aerosol permeation element according to claim 1.

7. A method of manufacturing an aerosol permeation element for use in an aerosol generating article, the method comprising: forming two or more strips into segments surrounding a conveying path; bringing the segments together into a sleeve former to form a sleeve; and introducing loose fibres between the segments upstream of the sleeve former such that they are drawn therein in a random orientation and compressed between the segments as they are brought together to form an aerosol permeable core within the sleeve.

8. Method according to claim 7, wherein the introduction of loose fibres comprises generating a turbulent flow of the fibres using a plurality of air jets oriented in different directions toward the inlet.

9. Method according to claim 7 comprising separating a tow into the two or more strips.

10. Method according to claim 7 comprising passing the strips over a guide, toward each other and into the sleeve former downstream of the guide such that the segments are substantially part-conical between the guide and the sleeve former, drawing the segments together into the sleeve former and causing the tow material of the segments to bond together by applying a plasticizer, or heat, or pressure, or any combination thereof, within the sleeve former to form an integral sleeve.

11. Method according to claim 7 comprising fragmenting a further strip formed from a tow to produce the loose fibres prior to their introduction between the segments.

12. Method according to claim 11, wherein fragmenting the further strip comprises passing the further strip between a set of crimping rollers which stretch and slit the further strip into the loose fibres.

13. Method according to claim 11 comprising separating a tow into at least three strips comprising the two or more strips and the further strip.

14. A method of manufacturing an aerosol generating article comprising manufacturing an aerosol permeation element using a method according to claim 7 and combining the aerosol permeation element with a tobacco containing rod.

15. An aerosol permeation element for use in an aerosol generating article, manufactured by the method of claim 7.

16. An aerosol permeation element for use in an aerosol generating article; wherein the sleeve or the core, or both the sleeve and core, of the aerosol permeation element comprises cellulose acetate or poly lactic acid fibres; and is manufactured by the method of claim 7.

17. An aerosol permeation element for use in an aerosol generating article; wherein the sleeve comprises a wall thickness of between 0.5 millimetres and 3 millimetres; and is manufactured by the method of claim 7.

18. An aerosol permeation element for use in an aerosol generating article; wherein the core comprises a diameter of between 2 millimetres and 8 millimetres; and is manufactured by claim 7.

Description

[0054] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

[0055] FIG. 1 is a perspective view of an aerosol permeation element according to an embodiment of the invention;

[0056] FIG. 2 is a cross-sectional view of the aerosol permeation element of FIG. 1;

[0057] FIG. 3 is a schematic of a filter manufacturing apparatus according to an embodiment of the invention;

[0058] FIG. 4 is a schematic of a tow as it is formed into three strips by the apparatus of FIG. 3;

[0059] FIG. 5 is a schematic of the central strip as it is stretched and slit by the apparatus of FIG. 3;

[0060] FIG. 6 is a perspective view of part of the filter manufacturing apparatus of FIG. 3;

[0061] FIG. 7 is a schematic of a filter manufacturing apparatus according to another embodiment of the invention;

[0062] FIG. 8 is a schematic of a tow as it is formed into two strips by the apparatus of FIG. 7;

[0063] FIG. 9 is a schematic of a further strip as it is stretched and slit by the apparatus of FIG. 7;

[0064] FIG. 10 is a perspective view of part of the filter manufacturing apparatus of FIG. 7.

[0065] Referring now to FIGS. 1 and 2, there is shown an aerosol permeation element 1 according to an embodiment of the invention, which is a filter part 1 (which can act as a cooling part) for an aerosol generating article (shown in outline). The filter part 1 in this embodiment includes an aerosol permeable core 11 of expanded, randomly oriented fibres. The core 11 is surrounded by a sleeve 12 of linear, axially oriented fibres. In this embodiment, the sleeve 12 has a wall thickness W of 1 millimetre and the aerosol permeable core 11 has a diameter D of 5 millimetres. The core 11 may be configured to provide a resistance to draw of between 0.5 millimetres, water gauge (mmWG) and 2 millimetres, water gauge (mmWG) per millimetre of axial length of the filter part 1, depending on the materials used and the processing parameters used during the manufacture thereof.

[0066] FIGS. 3 to 6 show an apparatus 10 for manufacturing the filter part 1 of FIGS. 1 and 2. As illustrated in FIG. 3, a length of tow 2 is fed from a storage container 20 via a feed assembly 3 and through a separator 4, which separates the tow 2 into three strips 2a, 2b, 2c. A central strip 2b is fed into a fragmentation delivery device 5, while outer strips 2a, 2c are fed to a guide 6 that partially surrounds a conveying path along which the central strip 2b is conveyed. The delivery device 5 fragments the central strip 2b into a plurality of fibres 52 and introduces them between the outer strips 2a, 2c as they pass over the guide 6. The outer strips 2a, 2c and fibres 52 introduced between them are received within a sleeve former 7, which brings the strips 2a, 2c and fibres 52 together, compresses them and joins the outer strips 2a, 2c about the fibres 52 to form the filter rod 8.

[0067] In this embodiment, the tow 2 is formed of poly lactic acid (PLA) fibres aligned longitudinally along its length. The tow feed assembly 3 has a pair of tensioning rollers 31 for creating tension in the tow 2 as it is conveyed into the tow separator 4 from the storage container 20. The tow separator 4 is located downstream of the tow feed assembly 3 and includes a pair of opposed, counter-rotating separation rollers 4a, 4b configured, in use, to rotate in the conveying direction of the apparatus 10 at a speed R1. Each of the separation rollers 4a, 4b has a pair of cutters or blades 41a, 41b (shown in FIG. 6), which cooperate with those of the other roller 4b, 4a to slit the tow 2 as it passes therebetween. As a result, the tow separator 4 splits the tow 2 from the tow feed assembly 3 into three strips, namely the outer strips 2a, 2c and the central strip 2b.

[0068] The delivery device 5 is downstream of the tow separator 4 and has a pair of opposed, counter-rotating crimping rollers 5a, 5b arranged to rotate in the conveying direction of the apparatus 10. In this embodiment, the crimping rollers 5a, 5b rotate at a speed R2, which is selected to create a greater interface speed than that of the tow separator 4, thereby stretching the central strip 2b as it passes between them. Each of the crimping rollers 5a, 5b has a plurality of grooves (not shown) on its surface, which provide a crimping effect as the central strip 2b passes therethrough, and cutting elements or blades (not shown), which cut the central strip 2b as it passes between them. The stretching caused by the speed R2 of the crimping rollers 5a, 5b, together with the grooves and cutting elements or blades (not shown), slit and stretch the central strip 2b of the tow 2 as it passes therethrough.

[0069] The delivery device 5 also has a flow inducer in the form of air jets 51 downstream of the crimping rollers 5a, 5b, which are distributed around the exit of the crimping rollers 5a, 5b and are directed downstream and toward the conveying path. As such, each jet 51 induces a flow downstream and toward the conveying path, which impinges the flow from the other jet(s) 51 to generate a turbulent flow of fibres 52 as they exit the crimping rollers 5a, 5b.

[0070] The guide 6 is also downstream of the tow separator 4 and includes a pair of opposed, spaced part-conical and tubular guide members 61a, 61b (shown more clearly in FIG. 6). An upper guide member 61a lies above the conveying path and a lower guide member 61b lies below the conveying path. Together, the guide members 61a, 61b partially surround the conveying path, with a vertical gap A between them. Each of the guide members 61a, 61b tapers inwardly toward the sleeve former 7. The downstream ends of the guide members 61a, 61b are spaced from the sleeve former 7 by a distance B. In this embodiment, the jets 51 are adjacent the upstream end of the guide members 61a, 61b, such that the turbulent flow of fibres 52 is directed into the space between the guide members 61a, 61b and toward the sleeve former 7.

[0071] The sleeve former 7 has a first, conical segment or forming funnel 71 and a second, tubular element 72 downstream of the conical segment 71. The conical segment 71 tapers inwardly along a conveying direction to the diameter of the tubular element 72. The sleeve former 7 is heated in this embodiment, such that the outer strips 2a, 2c of tow 2 are bonded together by both heat and compression as they are conveyed, together with the fibres 52 from the central strip 2b of the tow 2, through the sleeve former 7. The sleeve former 7 also includes a drawing mechanism 73 for drawing a length of completed filter rod 8 through and out of the tubular element 72 of the sleeve former 7. The drawing mechanism 73 includes a motor 74 and a conveying belt 75 for pulling or drawing the filter rod 8. The apparatus 1 may also include an integral cutting station (not shown) downstream of the sleeve former 7 to cut the rod into filter parts 1. Alternatively, the filter rod 8 may be fed into another apparatus for further processing.

[0072] In use, a length of tow 2 is fed from the storage container 20 via the tensioning rollers 31 of the tow feed assembly 3 and into the tow separator 4. The tow 2 passes between the rollers 4a, 4b of the tow separator 4, where the cutters 41a, 41b split the tow 2 into the outer and central strips 2a, 2b, 2c. The outer strips 2a, 2c are separated from the conveying path, with a first outer strip 2a passing over the upper guide member 61a and a second outer strip 2c passing over the lower guide member 61b. The outer strips 2a, 2c expand and conform to the profile of the respective guide member 61a, 61b as they are passed thereover. The guide members 61a, 61b create tension in the outer strips 2a, 2c and guide them toward the sleeve former 7. The guide members 61a, 61b deform and stretch the outer strips 2a, 2c into part-conical, tubular segments that partially surround the conveying path of the apparatus 10.

[0073] The central strip 2b is fed from the tow separator 4 into the delivery device 5 and passes between the crimping rollers 5a, 5b, which stretch, slit and fragment the central strip 2b to form a modified tow region 21b of loose fibres 52. Once the central strip 2b has passed through the crimping rollers 5a, 5b the modified tow region 21b is acted upon by the air jets 51, which generate the turbulent flow of fibres 52. The air jets 51 act on the fibres 52 such that they are directed downstream and toward the conveying path and into the space between the guide members 61a, 61b.

[0074] The fibres 52 are drawn into the sleeve former 7 in a random orientation along with the part-conical, tubular outer strips 2a, 2c. The outer strips 2a, 2c are suspended between the downstream end of the guide members 61a, 61b and the sleeve former 7 such that they are exposed to the fibres 52. The outer strips 2a, 2c may have a plasticizer applied thereto as they pass over the guide members 61a, 61b, for example from a plasticizer spraying apparatus (not shown). The application of a plasticizer not only facilitates the bonding of the outer strips 2a, 2c, but it also causes the fibres 52 to adhere to the outer strips 2a, 2c as they come into contact with them.

[0075] The outer strips 2a, 2c are brought together as they are drawn into the conical segment 71 of the sleeve former 7. The fibres 52 are compressed gradually between the outer strips 2a, 2c as they are conveyed from the conical segment 71 toward the tubular element 72. The longitudinal edge regions of the outer strips 2a, 2c overlap as they enter the sleeve former 7. As such, the overlapping regions are bonded together, using heat and compression, as the outer strips 2a, 2c pass through the sleeve former 7 such that they describe a sleeve surrounding the fibres 52 to form a length of filter rod 8. The drawing mechanism 73 draws the filter rod 8 through and out of end of the tubular element 72 for processing or cutting into a plurality of filter parts 1 (or both processing and cutting into a plurality of filter parts).

[0076] The central and outer strips 2a, 2b, 2c are formed from the same tow 2. As such, the core 11 and sleeve 12 of an aerosol permeation element 1 made using this apparatus 10 are formed from the same material. In some embodiments, however, one or more of the strips 2a, 2b, 2c may undergo further intermediate processing, for example chemical processing, to alter its properties. Additionally or alternatively, the fibres 52 may undergo further processing, for example chemical processing, prior to being introduced, or as they are introduced, into the sleeve former 7.

[0077] It will be appreciated by those skilled in the art that the parameters of the filter part 1 may be altered by changing one or more processing parameters. For example, the quantity or density of fibres 52 may be increased or decreased by changing the width of the central strip 2b wider, for example by changing the space between the cutters 41a, 41b of the separation rollers 4a, 4b. The thickness of the sleeve 12 may be increased or decreased in a similar manner. Additionally or alternatively, the thickness of the sleeve 12 may be changed by modifying the extent to which the outer strips 2a, 2c are stretched, for example by changing the difference between the speed R1 of the separation rollers 4a, 4b and the rate at which the drawing mechanism 73 draws the finished rod 8. Similarly, each of the central and outer strips 2a, 2b, 2c may be treated at various stages of the process to alter their characteristics.

[0078] As such, the invention provides a versatile means of producing aerosol permeation elements 1 whose characteristics can be varied across a wide range.

[0079] Referring now to FIGS. 5 to 8, there is shown an apparatus 100 according to another embodiment of the invention for manufacturing filter parts 1 having a core 11 formed of a different material to the sleeve 12. The apparatus 100 according to this embodiment is similar to the apparatus 10 of the first embodiment, wherein like features are denoted by like references, which will not be described further. The apparatus 100 differs from that of the first embodiment in that the central strip 2b is provided by a different tow 102 to the tow 2 from which the outer strips 2a, 2c are formed. The different tow 102 may be formed of a different material or have one or more different characteristics (or both be formed of a different material and have one or more different characteristics) to the tow 2 from which the outer strips 2a, 2c are formed.

[0080] The apparatus 100 includes a tow separator 104 having a pair of opposed, counter-rotating separation rollers 141, 142 each having a single, opposed cutter or blade 143, 144. The separation rollers 141, 142 operate in substantially the same manner as those of the first embodiment, except that the cutters 143, 144 cooperate to split the tow 2 only into the outer strips 2a, 2c in this embodiment. The apparatus 100 has a further tow storage container 120 of the different tow 102 and a further tow feed assembly 103. The further tow feed assembly 103 has a further pair of tensioning rollers 131 for creating tension in the tow 102 as it is conveyed into the apparatus 100. The further tow feed assembly 103 also includes alignment rollers 132, 133 for aligning the tow 102 prior to entry into the delivery device 5.

[0081] More specifically, a first pair of alignment rollers 132 is external of the conveying path, while a second alignment roller 133 is within the conveying path, immediately upstream of the crimping rollers 5a, 5b. The tow 102 is fed from the storage container 120 to the delivery device 5 via the alignment rollers 132, 133 such that it passes between the outer strips 2a, 2c downstream of the tow separator 104 and into the conveying path between the tow separator 104 and the guide 6. As illustrated in FIGS. 7 and 10, the axes of rotation of the alignment rollers 132, 133 lie at an angle relative to the separation rollers 141, 142 and crimping rollers 5a, 5b to enable transverse feeding of the tow 102 through the vertical gap between the outer strips 2a, 2b. In this embodiment, the tensioning rollers 131, alignment rollers 132, 133 and strip feed roller 133 are non-driven.

[0082] In use, the tow 2 is fed into the tow separator 104 via the tow feed assembly 3 and is split into outer strips 2a, 2c by the separation rollers 141, 142. The outer strips 2a, 2c are conveyed through the apparatus 100 in a similar way to the apparatus 10. The further length of tow 102 is fed from the storage container 120 via the further tow feed assembly 103 into the delivery device 5. The further length of tow 102 provides the central strip in this embodiment. The further tow 102 is fed into the delivery device 5 and passes between the pair of crimping rollers as per apparatus 10, where a modified tow region 121 of loose fibres 152 is created. The modified tow region 121 is fragmented and a turbulent flow of fibres 152 created, as per apparatus 10.

[0083] It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention. For example, the number of strips 2a, 2c used to form the sleeve 12 may be more than two in number. The strip or strips 2a, 2c used to form the sleeve may undergo further intermediate processing, for example chemical processing, to alter their properties. Moreover, while the outer strips 2a, 2c are described as being bonded together using heat and pressure, this need not be the case. They may be secured together using an adhesive. Similarly, the outer strips 2a, 2c may, but need not, include a plasticizer applied thereto. Moreover, while the flow inducer 51 described as being a pair of opposed air jets this need not be the case. The flow inducer 51 may be one or more fans or blowers or any combination thereof or any other suitable flow inducing means. Other variations are also envisaged and would be appreciated by those skilled in the art.

[0084] It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features and those features shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.