SMOKING SUBSTITUTE CONSUMABLE

Abstract

An aerosol-forming article is disclosed having an improved filter at its axial downstream end, for instance a mouthpiece end. The improved filter comprises a filter segment having a plurality of bores extending there through, wherein a cooling segment is arranged upstream of the filter segment, the cooling segment comprising portion having a central bore that forms a central region extending around a central axis of the aerosol-forming article and a center of each bore of the plurality of bores is arranged radially outside of the central region.

Claims

1. An aerosol-forming article comprising a filter segment having a plurality of bores extending there through, wherein a cooling segment is arranged upstream of the filter segment, the cooling segment comprising a portion having a central bore that forms a central region extending around a central axis of the aerosol-forming article and a center of each bore of the plurality of bores is arranged radially outside of the central region.

2. The aerosol-forming article of claim 1, wherein each bore of the plurality of bores are open to the exterior at a mouth-end of the aerosol-forming article.

3. The aerosol-forming article of claim 2, wherein the filter segment comprises a body and the plurality of bores extend from one distal face of the body to an opposed distal face of the body.

4. The aerosol-forming article of any of claim 1 or claim 3, wherein the distal face arranged at a downstream end of the filter segment coincides with a distal end of the aerosol-forming article.

5. The aerosol-forming article of any of claim 1 to claim 4, wherein the filter segment has a generally elongate form having a central axis and each bore of the plurality of bores extends parallel to the central axis.

6. The aerosol-forming article of any of claim 1 to claim 5, wherein each bore of the plurality of bores has a circular cross-section that is constant along the length of the filter segment.

7. The aerosol-forming article of any of claim 1 to claim 6, wherein the diameter of the central bore of the portion of the cooling segment has a diameter between 40% and 45% of a diameter of an external surface of said portion.

8. The aerosol-forming article of any of claim 1 to claim 7, wherein the centers of each bore are arranged equally spaced about a notional circle.

9. The aerosol-forming article of any of claim 1 to claim 8, wherein said portion is a first portion and the cooling segment includes a second portion having a larger airflow passage than an airflow passage created by the central bore of the first portion.

10. The aerosol-forming article of claim 9, wherein the second portion comprises a spacer element having a central bore with a diameter greater than 95% of the diameter of an external surface of said portion comprising the spacer element.

11. The aerosol-forming article of any of claims 1 to 10, wherein a total cross-sectional area of the plurality of bores is less than 20% of the cross-sectional area of the filter segment, or wherein a total cross-sectional area of the plurality of bores is less than 15% of the cross-sectional area of the filter segment or less than 10% of the cross-sectional area of the filter segment or around 6% of the cross-sectional area of the filter segment.

12. A system comprising a smoking substitute article according to any one of the preceding claims and a device comprising a heating element.

13. The system according to claim 12 wherein the device comprises a main body for housing the heating element and the heating element comprises an elongated heating element.

14. A method of using the system according to claim 12 or 13, the method comprising: inserting the article into the device; and heating the article using the heating element.

15. A method according to claim 14 comprising inserting the article into a cavity within a main body of the device and penetrating the article with the heating element upon insertion of the article.

Description

SUMMARY OF THE FIGURES

[0069] So that the disclosure may be understood, and so that further aspects and features thereof may be appreciated, embodiments illustrating the principles of the disclosure will now be discussed in further detail with reference to the accompanying figures, in which:

[0070] FIG. 1 shows a schematic cross-sectional view of an aerosol-forming article;

[0071] FIGS. 2A, 2B and 2C show schematic cross-sectional views through a filter segment of the aerosol-forming article of FIG. 1 with additional virtual markings for explanation; and

[0072] FIG. 3 shows a schematic cross-sectional view through a smoking substitute system wherein the aerosol-forming article of FIG. 1 is inserted into a heating device.

DETAILED DESCRIPTION OF THE FIGURES

[0073] Referring to FIG. 1, an aerosol-forming article 10 is generally shown having an aerosol-forming substrate 20 at one distal end and a filter segment 100 at an opposed distal. Suitably, the aerosol-forming article 10 is shown as having a cooling segment 30 disposed between the aerosol-forming substrate 20 and the filter segment 100. Here, the aerosol-forming substrate 20 is arranged at an upstream end of the cooling segment 30 and the filter segment is arranged at a downstream end thereof. As used herein, the terms “upstream” and “downstream” are intended to refer to the flow direction of the vapor/aerosol, i.e., with the downstream end of the article/consumable being the mouth end or outlet where the aerosol exits the article/consumable for inhalation by the user. The upstream end of the article/consumable is the opposing end to the downstream end.

[0074] As shown in FIG. 1, the aerosol-forming article 10 is suitably a Heat Not Burn (HNB) consumable comprising the aerosol-forming substrate 20 at the upstream end of the consumable 10. The aerosol-forming substrate comprises reconstituted tobacco which includes nicotine as a volatile compound.

[0075] The aerosol-forming substrate 20 comprises 65 wt % tobacco which is provided in the form of gathered shreds produced from a sheet of slurry/paper recon tobacco. The tobacco is dosed with 20 wt % of a humectant. Here, propylene glycol (PG) or vegetable glycerin (VG) are suitable humectants, either used individually or mixed together or with other materials. Ideally, the aerosol-forming substrate has a moisture content of between 7-9 wt %, but the moisture content may be wider than this range. The aerosol-forming substrate further comprises cellulose pulp filler and guar gum binder.

[0076] The aerosol-forming substrate 20 is formed in a substantially cylindrical shape such that the consumable resembles a conventional cigarette. Here, the cylindrical shape has a generally longitudinal extend having a central axis A. Moreover, the aerosol-forming substrate has a generally circular cross-sectional shape of generally uniform and consistent shape along the length of the substrate. Suitably, the aerosol-forming substrate has diameter of around 7 mm and an axial length of around 12 mm. That is, the aerosol-forming substrate 20 has a length around 170%-175% greater than its diameter.

[0077] The aerosol-forming article 10 is circumscribed by a paper wrapping as is generally known in the art. In FIG. 1, the paper wrapping is indicated generally by reference 60. Here, the paper wrapping may comprise a single paper wrapping layer, however, a plurality of paper wrapping layers 61, 62 are shown in FIG. 1. In addition, the aerosol-forming substrate is circumscribed by a separate paper wrapping layer (not shown) so as to form a wrapped tobacco rod. The wrapped tobacco rod is wrapped again with paper wrapping layer 61 to assemble the aerosol-forming article 10.

[0078] The aerosol-forming article 10 comprises a cooling segment 30. As shown, the cooling segment 30 comprises a first portion 40 and a second portion 50. The first portion 40 is shown as an upstream portion and, as will be described, can be termed a Hollow Bore Filter (HBF) element. The second portion 50 is shown as a downstream portion and, as will be described, can be termed a spacer element. As shown, both portions have central bores, wherein, when aligned as a cooling segment 30 as a single unit, the central bores are coaxial. Here, the combined central bore of the cooling element includes a step wherein the central bore increase in size in a downstream direction. Suitably, the spacer element 50 is a cardboard spacer tube or the like. The HBF element 40 and spacer element 50 are circumscribed by the wrapping layer 61. Thus, the parts have a substantially equal outer diameter. As shown, the wrapping layer 61 is a single wrapping layer 60 that wraps at least a portion of each of the aerosol-forming substrate, the first portion 40 and the second portion 50. Thus, the exterior diameter of the aerosol-forming substrate 20 is substantially the same as the exterior diameter of the cooling segment 30. As shown, the wrapping layer circumscribes substantially the entire length of each element. As will be understood, the wrapping layer 61 is used to maintain the elements in a single unit, wherein the elements have been aligned and abutted against each other to form a generally cylindrical unit. Here, the generally cylindrical unit has a central axis A. As will be understood, the cooling segment 30 therefore forms a generally cylindrical unit having a circular cross-section of generally uniform and consistent exterior shape along the length of the cooling segment 30.

[0079] The first portion 40 of the cooling element has a central bore 42. The central bore 42 is also generally cylindrical in shape and therefore has a generally circular cross-sectional shape having a constant and consistent size along the length of the first portion 40. The axial length of the first portion 40 is suitably around 10 mm and the diameter around 7 mm. Thus, the first portion 40 has a length around 140%-150% of the diameter. The central bore 42 suitably has a diameter around 3 mm. Thus, the diameter of the central bore 42 has a diameter of around 42%-43% of the diameter of the first portions exterior surface. Suitably though the diameter of the central bore 42 may be between 40% and 45% of the diameter of the first portions exterior surface. That is, the diameter of the central bore 42 may be between around 2.8 mm to 3.2 mm. Moreover, for non-circular bores and exterior shapes, the relationship between the bore size and overall size may be expressed in relation to area, wherein the cross-sectional area of the central bore 42 may be around 17%-18% and between 15% and 20% of the cross-sectional area of the first portion. As will be appreciated, the size of the first element 40 having a central bore 42 with an appropriate relative size provides an element that might also be referred to as a HBF element.

[0080] The second portion 50 of the cooling element has a central bore 52. The central bore 52 is also generally cylindrical in shape and therefore has a generally circular cross-sectional shape having a constant and consistent size along the length of the second portion 50. The axial length of the second portion 50 is suitably around 10 mm and the diameter around 7 mm. Thus, the second portion 50 has a length around 140%-150% of the diameter. Moreover, the first portion 40 and the second portion 50 are generally similar in external size. However, the second portion 50 has an enlarged central bore size as compared to the first portion 40. For instance, the second portion 50 is shown as a thin-walled tube. Here, a wall 54 of the second portion 50 may have a wall thickness of around 0.04 mm. Thus, the central bore 52 of the second portion 50 has a diameter around 99% of the diameter of the exterior surface of the second portion 50. As will be appreciated, the size of the second portion 50 having a central bore 52 with an appropriate relative size provides an element that might also be referred to as a spacer element. Specifically, the filter element 100 may be formed by a cardboard tube or the like.

[0081] As will be appreciated, the elements of the aerosol-forming article 10, that is the aerosol-forming substrate 20, the cooling element 30 (including the first portion 40 and the second portion 50) and the filter element 100, form an article having a generally cylindrical form where the elements each have a central axis that are assembled to be coincident along axis A. Moreover, during assembly, the elements can be abutted against each other to maintain an axial spacing. Specifically, the spacer element 50 can abut between the filter segment 100 and the upstream element (for instance, the first portion), wherein the spacer element 50 abuts distal faces of the respective parts.

[0082] The filter element 100 includes a plurality of bores 102, 104, 106 that extend through a body 110 of the filter element 100. The body 110 is formed in a substantially cylindrical shape such that the consumable 10 resembles a conventional cigarette. Here, the cylindrical shape has a generally longitudinal extend having a central axis A. Moreover, the filter segment 100 has a generally circular external cross-sectional shape of generally uniform and consistent shape along the length of the filter segment 100. Suitably, the filter segment 100 has diameter of around 7 mm and an axial length of around 12 mm. That is, the filter element 100 has a length around 170%-175% of its diameter. As explained, the external diameter of the cooling element 30 matches the external diameter of the aerosol-forming substrate 20. The external diameter of the filter segment 100 is slightly larger and matches the combined diameter of the aerosol-forming substrate 20 and the wrapping layer 60. The filter segment 100 is joined to the upstream elements forming the consumable by a circumscribing paper tipping layer 62. The tipping layer 62 encircles the filter element 100 and has an axial length of around 20 mm such that it overlays a portion of the cooling segment 30. As shown, the paper tipping layer 62 may be separate to the wrapping paper 60 and therefore one of the wrapping papers also circumscribes the other.

[0083] The body 110 of the filter segment 100 has opposing distal end faces. Since the filter segment 100 is generally cylindrical, the distal end faces are radial end faces. Here, the radial end faces are longitudinally opposed along a central axis. As shown, the body has an upstream distal face 112 and a downstream distal face 114. The bores extend between the distal faces 112, 114 and provide discrete airflow passages there between through which the aerosol is drawn from the central bore 52 of the spacer element 50 for delivery to a user's mouth at the downstream distal face 114 of the aerosol-forming article 10. As shown, the plurality of bores 102, 104, 106 are substantially identical. Moreover, they are arranged parallel to each other and to extend parallel to the central axis A. Preferably, as shown in FIG. 1, each bore 102, 104, 106 has a generally uniform and consistent circular cross-section along the length of the filter segment 100.

[0084] Referring to FIG. 2A, the arrangement of the plurality of bores 102, 104, 106 is explained. The plurality of bores may comprise more than two or more than three bores, but according to the exemplary embodiment shown in FIG. 3, the plurality of bores consists of three bores 102, 104, 106. As will be appreciated, where other number of bores are adopted, the description of the bores herein is equally applicable.

[0085] Referring to one bore 102, the bore 102 has a circular cross-sectional area having a diameter of around 1 mm. However, it is envisaged that a bore diameter of between 0.5 mm and 1.5 mm or between 0.7 mm to 1.3 mm, or between 0.8 mm and 1.2 mm would be applicable. That is, the diameter of the bore 102, is suitably between 7% and 21% or between 10% and 19% or between 11% and 16% of the external diameter of the filter segment 100, but preferably between around 14-15% of the external diameter of the filter segment 100. Moreover, the cross-sectional area of the bore is therefore between 0.5% and 4.5% or between 1% and 3.3% or between 1.2% and 2.9% or preferably around 1.9% to 2% of the cross-sectional area of the filter segment 100.

[0086] The number and size of the plurality of bores 102, 104, 106 is suitably controlled to provide a filter element 100 having a porosity of around 6%. Here, the porosity is a calculation of the total cross-sectional area of the plurality of bores 102, 104, 106 relative to the total cross-sectional area of the filter segment 100. As shown, each bore has a cross-sectional area of around 0.79 mm∧2. Having three bores, the total cross-sectional area of the plurality of bores 102, 104, 106 is around 2.36 mm∧2. Thus, as shown the porosity is around 6%. However, it is envisaged, the porosity could be selected so that the total cross-sectional area of the plurality of bores is less than 20% or less than 15% or less than 10% of the cross-sectional area of the filter segment 100, which has an area of 39.81 mm2. It is thought that by selecting the porosity of the filter element beneath the limit finds a balance between low drag resistance and the provision of a good filter. For instance, with higher porosities that would further reduce the drag resistance of the filter element 100 it is likely that debris would not be adequately filtered. Thus, an additional filter tow would be needed and it is believed the drag resistance of the disclosed filter element would be lower than a combination of a filter tow and a filter element having a higher porosity.

[0087] As shown in FIG. 2B, the plurality of bores 102, 104, 106 are spaced around a notional circle 120. Here, the centers of each bore 102, 104, 106 are arranged on a notional circle 122 centered on the central axis A of the filter segment 100. Suitably, the notional circle 122 has a radius or around 1.55 mm. However, it is envisaged that the radius of the notional circle upon which the bore centers are arranged is between 30% and 60% or between 40% and 50% and preferably around 42%-44% of the radius of the external surface of the filter segment 100. As shown, the plurality of bores 102, 104, 106 are equally spaced around the notional circle 122. That is, the angle subtended between each adjacent bore 102, 104, 106 is equal.

[0088] Although the bores 102, 104, 106 being arranged around a notional circle 122 is particularly suitable, it is envisaged that other arrangements may be applicable. Advantageously however, and as shown in FIG. 2a, the plurality of bores 102, 104, 106 are arranged to provide a central region wherein no bores are formed. For instance, the central region is shown bounded by circle 120. No bore is provided within the central, circular region 120. Suitably, the circle 120 has a diameter of around 2.1 mm. However, it is envisaged that a central area bounded by a circle having a radius of between 43% and 20% of the external radius of the filter element 100, could generate an advantageous tortuous airflow path.

[0089] In particular, as shown in FIG. 2C, the tortuous path generated by the airflow is thought to be created, at least in part, by the centers of the plurality of bores 102, 104, 106 being arranged outside a central region that corresponds to the maximum restriction (e.g., the narrowest portion of the airflow path) in the cooling segment 30. For instance, as shown, the minimum restriction in the cooling segment 30 is provided by the central bore 42 of the HBF element 40. In FIG. 2c the central bore of the HBF element is shown as circle 124. Here, each bore 102, 104, 106 is arranged so that the center of the bore is arranged radially outside of the central region. The circle 124 (and therefore the central bore 42) typically has a radius of around 1.5 mm.

[0090] The plurality of bores 102, 104, 106 in the filter segment 100 are suitably open to the mouth end of the aerosol-forming article 10. As shown in FIG. 1, here, the filter segment 100 is a terminal filter segment, wherein the distal end 114 forms a distal end of the article 10. Or in other words, the distal end 114 forms a plane and the aerosol-forming article 10 does not extend downstream from the plane. However, in the event that an element of the aerosol-forming article 10 extends downstream from the distal end of the filter segment 100, the plurality of bores 102, 104, 106 would remain open to a mouth end if the bores 102, 104, 106 can virtually extend unimpeded to the distal end of the aerosol-forming article 10.

[0091] FIG. 3 shows the aerosol-forming article 10 inserted into a device 70. Suitably, the device 70 is a HNB device comprising a rod-shaped heating element (not shown). The heating element projects into a cavity 72 within a main body 74 of the device 10.

[0092] The consumable 10 is inserted into the cavity 72 of the main body 74 of the device 70 such that the heating rod penetrates the aerosol-forming substrate 20. Heating of the reconstituted tobacco in the aerosol-forming substrate 20 is effected by powering the heating element (e.g., with a rechargeable battery (not shown)). As the tobacco is heated, moisture and volatile compound (e.g., nicotine) within the tobacco and the humectant are released as a vapor and entrained within an airflow generated by inhalation by the user at the filter element 100.

[0093] The airflow is drawn through the aerosol-forming article as is known in the art. For example, from the aerosol-forming substrate 20, the airflow follows a path through the central bore of the HBF portion 40 of the cooling segment 30 and then through the central bore of the spacer segment 50. As the vapor cools within the HBF segment 40 and the cardboard spacer element 50, it condenses to form an aerosol containing the volatile compounds for inhalation by the user. The airflow continues and is drawn through the filter segment 100 and specifically the plurality of bores 102, 104, 106 that extend through the filter segment 100. It is believed that the arrangement of the plurality of bores 102, 104, 106 through the filter segment 100 produces an improved delivery of the aerosol to the user. For instance, as the airflow is caused to expand from the HBF segment 40 to the spacer element 50 and then through the plurality of bores 102, 104, 106, an advantageous airflow is generated to create an improved mixing of the airflow. The arrangement of the plurality of bores 102, 104, 106 may create a Venturi effect in the spacer element 50 as the user inhales to generate the airflow through the article 10, wherein the Venturi effect in the airflow helps mix the nicotine and vapor to create a smooth experience. Moreover, the filter element 100 has been found to provide good filtering of the airflow whilst providing a lower drag resistance as compared to a filter tow. It is believed the combination of high filtering and low drag resistance may be achieved by creating a tortuous airflow path from the aerosol-forming substrate 20 to downstream end of the filter segment 100.

[0094] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilized for realizing the disclosure in diverse forms thereof.

[0095] While the disclosure has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the disclosure set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the scope of the disclosure.

[0096] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0097] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0098] Throughout this specification, including the claims which follow, unless the context requires otherwise, the words “have”, “comprise”, and “include”, and variations such as “having”, “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0099] It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means, for example, +/−10%.

[0100] The words “preferred” and “preferably” are used herein refer to embodiments of the disclosure that may provide certain benefits under some circumstances. It is to be appreciated, however, that other embodiments may also be preferred under the same or different circumstances. The recitation of one or more preferred embodiments therefore does not mean or imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure, or from the scope of the claims.

ILLUSTRATIVE EMBODIMENTS

[0101] The following numbered clauses, describing aspects of our proposals, are part of the description:

[0102] A1. An aerosol-forming article comprising a filter segment having a plurality of bores extending there through, wherein each bore of the plurality of bores are open to the exterior at a mouth-end of the aerosol-forming article.

[0103] A2. The aerosol-forming article of clause A1, wherein the filter segment comprises a body and the plurality of bores extend from one distal face of the body to an opposed distal face of the body.

[0104] A3. The aerosol-forming article of clause A2, wherein the distal face arranged at a downstream end of the filter segment coincides with a distal end of the aerosol-forming article.

[0105] A4. The aerosol-forming article of any of clause A1 to clause A3, wherein the filter segment has a generally elongate form having a central axis and each bore of the plurality of bores extends parallel to the central axis.

[0106] A5. The aerosol-forming article of any of clause A1 to clause A4, wherein each bore of the plurality of bores has a circular cross-section that is constant along the length of the filter segment.

[0107] A6. The aerosol-forming article of any of clause A1 to clause A5 including a cooling segment disposed upstream of the filter segment.

[0108] A7. The aerosol-forming article of clause A6 wherein at least a portion of the cooling segment includes a central bore.

[0109] A8. The aerosol-forming article of clause A7, wherein a diameter of the central bore is between 40% and 45% of a diameter of an external surface of said portion.

[0110] A9. The aerosol-forming article of clause A7 or clause A8, wherein the cooling segment includes at least a portion having a central bore with a cross-sectional area that forms a central region extending around the central axis and each of the plurality of bores has a center that is arranged radially outside of the central region.

[0111] A10. The aerosol-forming article of any of clause A7 to clause A9, wherein the cooling segment includes at least a portion having a central bore with a diameter greater than 95% of the diameter of an external surface of said portion.

[0112] All. The aerosol-forming article of any of clauses A1 to A10, wherein a total cross-sectional area of the plurality of bores is less than 20% of the cross-sectional area of the filter segment.

[0113] A12. A system comprising a smoking substitute article according to any one of clauses A1 to A11 and a device comprising a heating element.

[0114] A13. The system according to clause A12 wherein the device comprises a main body for housing the heating element and the heating element comprises an elongated heating element.

[0115] A14. A method of using the system according to clause A12 or A13, the method comprising:

[0116] inserting the article into the device; and

[0117] heating the article using the heating element.

[0118] A15. A method according to clause A14 comprising inserting the article into a cavity within a main body of the device and penetrating the article with the heating element upon insertion of the article.

[0119] B1. An aerosol-forming article comprising a filter segment having a plurality of bores extending there through, wherein adjacent and upstream to the filter segment there is arranged a spacer element.

[0120] B2. The aerosol-forming article of clause B1, wherein each bore of the plurality of bores are open to the exterior at a mouth-end of the aerosol-forming article.

[0121] B3. The aerosol-forming article of clause B2, wherein the filter segment comprises a body and the plurality of bores extend from one distal face of the body to an opposed distal face of the body.

[0122] B4. The aerosol-forming article of any of clause B1 to clause B3, wherein the distal face arranged at a downstream end of the filter segment coincides with a distal end of the aerosol-forming article.

[0123] B5. The aerosol-forming article of any of clause B1 to clause B4, wherein the filter segment has a generally elongate form having a central axis and each bore of the plurality of bores extends parallel to the central axis.

[0124] B6. The aerosol-forming article of any of clause B1 to clause B5, wherein each bore of the plurality of bores has a circular cross-section that is constant along the length of the filter segment.

[0125] B7. The aerosol-forming article of any of clause B1 to clause B6 including a cooling segment disposed upstream of the filter segment, wherein at least a portion of the cooling segment comprises the spacer element.

[0126] B8. The aerosol-forming article of clause B7, wherein a first portion of the cooling segment has a central bore with a diameter between 40% and 45% of a diameter of an external surface of the cooling segment and a second portion of the cooling segment is the spacer element having a central bore.

[0127] B9. The aerosol-forming article of clause B8, wherein the first portion has a central bore with a cross-sectional area that forms a central region extending around the central axis and each of the plurality of bores has a center that is arranged radially outside of the central region.

[0128] B10. The aerosol-forming article of any of clause B1 to clause B9, wherein the spacer element has a central bore with a diameter greater than 95% of the diameter of an external surface of said portion comprising the spacer element.

[0129] B11. The aerosol-forming article of any of clauses B1 to B10, wherein a total cross-sectional area of the plurality of bores is less than 20% of the cross-sectional area of the filter segment.

[0130] B12. A system comprising a smoking substitute article according to any one of clauses B1 to B11 and a device comprising a heating element.

[0131] B13. The system according to clause B12 wherein the device comprises a main body for housing the heating element and the heating element comprises an elongated heating element.

[0132] B14. A method of using the system according to clause B12 or B13, the method comprising:

[0133] inserting the article into the device; and

[0134] heating the article using the heating element.

[0135] B15. A method according to clause B14 comprising inserting the article into a cavity within a main body of the device and penetrating the article with the heating element upon insertion of the article.

[0136] C1. An aerosol-forming article comprising a filter segment having a plurality of bores extending there through, wherein a total cross-sectional area of the plurality of bores is less than 20% of the cross-sectional area of the filter segment.

[0137] C2. The aerosol-forming article of clause C1, wherein each bore of the plurality of bores are open to the exterior at a mouth-end of the aerosol-forming article.

[0138] C3. The aerosol-forming article of clause C2, wherein the filter segment comprises a body and the plurality of bores extend from one distal face of the body to an opposed distal face of the body.

[0139] C4. The aerosol-forming article of any of clause C1 to clause C3, wherein the distal face arranged at a downstream end of the filter segment coincides with a distal end of the aerosol-forming article.

[0140] C5. The aerosol-forming article of any of clause C1 to clause C4, wherein the filter segment has a generally elongate form having a central axis and each bore of the plurality of bores extends parallel to the central axis.

[0141] C6. The aerosol-forming article of any of clause C1 to clause C5, wherein each bore of the plurality of bores has a circular cross-section that is constant along the length of the filter segment.

[0142] C7. The aerosol-forming article of any of clause C1 to clause 6 including a cooling segment disposed upstream of the filter segment.

[0143] C8. The aerosol-forming article of clause C7, wherein at least a portion of the cooling segment has a central bore with a diameter between 40% and 45% of a diameter of an external surface of said portion.

[0144] C9. The aerosol-forming article of any of clause C7 or clause C8, wherein the cooling segment includes at least a portion having a central bore with a cross-sectional area that forms a central region extending around the central axis and each of the plurality of bores has a center that is arranged radially outside of the central region.

[0145] C10. The aerosol-forming article of any of clause C7 to clause C9, wherein the cooling segment includes a portion comprising a spacer element having a central bore with a diameter greater than 95% of the diameter of an external surface of said portion comprising the spacer element.

[0146] C11. The aerosol-forming article of any of clauses C1 to C10, wherein a total cross-sectional area of the plurality of bores is less than 15% of the cross-sectional area of the filter segment or less than 10% of the cross-sectional area of the filter segment or around 6% of the cross-sectional area of the filter segment.

[0147] C12. A system comprising a smoking substitute article according to any one of clauses C1 to C11 and a device comprising a heating element.

[0148] C13. The system according to clause C12 wherein the device comprises a main body for housing the heating element and the heating element comprises an elongated heating element.

[0149] C14. A method of using the system according to clause C12 or C13, the method comprising:

[0150] inserting the article into the device; and

[0151] heating the article using the heating element.

[0152] C15. A method according to clause C14 comprising inserting the article into a cavity within a main body of the device and penetrating the article with the heating element upon insertion of the article.