Patent Description:
Cigarettes and other smoking articles produce an aerosol, such as smoke in the case of cigarettes, which is inhaled by a user. A filter may be provided as part of a smoking article, or can be provided as a separate component which can be attached or coupled to a smoking article by a user. Filters can be configured to modify properties of aerosol produced by the smoking article; for example, by adding flavourant to the aerosol produced by the smoking article.

<CIT> relates to a smoking article including a tube and a filter block connected by a sleeve, thereby constituting a filter unit.

According to embodiments of the invention, there is provided a filter unit as set out in claim <NUM>.

An inner diameter of the second portion can be greater than an inner diameter of the first portion.

An outer diameter of the first portion is substantially the same as an outer diameter of the second portion.

Each of the first portion and the second portion can have a first end and a second end, and the second end of the first portion can adjoin the first end of the second portion and can have an inner diameter substantially the same as the first end of the second portion.

The tube can be formed from paper, card, cardboard or plastic.

The filter unit can comprise a cylindrical element, and the sleeve can at least partially surround the cylindrical element.

The cylindrical element can be formed from filter material and can comprise a body having an end surface adjacent to the tube and a recess formed in the end surface.

The cylindrical element can comprise an aerosol modifying substance disposed within the filter material of the cylindrical element. The aerosol modifying substance can comprise an encapsulated substance.

The filter unit can be arranged to be coupled to a smoking article by a user.

According to embodiments of the invention, there is also provided a smoking article comprising a filter unit as set out above.

The second portion of the tube can be disposed at a mouth end of the smoking article.

According to embodiments of the invention, there is also provided a kit comprising a smoking article and a filter unit as set out above.

As used herein, the term "tobacco industry product" is intended to include smoking articles comprising combustible smoking articles and their components such as cigarettes, cigarillos, cigars, tobacco for pipes or for roll-your-own cigarettes, (whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco, tobacco substitutes or other smokable material), electronic smoking articles and their components such as e-cigarettes, heating devices that release compounds from substrate materials without burning such as tobacco heating products, and hybrid systems to generate aerosol from a combination of substrate materials, for example hybrid systems containing a liquid or gel or solid substrate; and aerosol-free nicotine delivery articles and their components such as lozenges, gums, patches, articles comprising breathable powders and smokeless tobacco products such as snus and snuff. Components of the above articles include filter units, filter plugs, filter inserts and tubes for use in products such as smoking articles;.

In one embodiment, the tobacco industry product is a smoking article for combustion, selected from the group consisting of a cigarette, a cigarillo and a cigar.

In one embodiment, the tobacco industry product is a non-combustible smoking article.

In one embodiment, the tobacco industry product is a heating device which releases compounds by heating, but not burning, a substrate material. The material may be for example tobacco or other non-tobacco products, which may or may not contain nicotine. In one embodiment, the heating device is a tobacco heating device.

In one embodiment, the tobacco industry product is a hybrid system to generate aerosol by heating, but not burning, a combination of substrate materials. The substrate materials may comprise for example solid, liquid or gel which may or may not contain nicotine. In one embodiment, the hybrid system comprises a liquid or gel substrate and a solid substrate. The solid substrate may be for example tobacco or other non-tobacco products, which may or may not contain nicotine. In one embodiment, the hybrid system comprises a liquid or gel substrate and tobacco.

Filter units described herein can be provided to users as an integral component of a smoking article or as a discrete component separate from a smoking article. When provided separately, filter units and smoking articles can be packaged separately, or packaged together as a kit of parts.

Smoking articles such as cigarettes and their formats are often named according to the cigarette length: "regular" (typically in the range <NUM> - <NUM>, e.g. from about <NUM> to about <NUM>), "short" or "mini" (<NUM> or less), "king-size" (typically in the range <NUM> - <NUM>, e.g. from about <NUM> to about <NUM>), "long" or "super-king" (typically in the range <NUM> - <NUM>, e.g. from about <NUM> to about <NUM>) and "ultra-long" (typically in the range from about <NUM> to about <NUM>).

They are also named according to the cigarette circumference: "regular" (about <NUM> - <NUM>), "wide" (greater than <NUM>), "slim" (about <NUM> - <NUM>), "demi-slim" (about <NUM> - <NUM>), "super-slim" (about <NUM> - <NUM>), and "micro-slim" (less than about <NUM>). Accordingly, a cigarette in a king-size, super-slim format will, for example, have a length of about <NUM> and a circumference of about <NUM>. Cigarettes in the regular, king-size format are preferred by many customers, namely with a circumference of from <NUM> to <NUM> and an overall length of from <NUM> to <NUM>.

Each format may be produced with filters of different lengths, smaller filters being generally used in formats of smaller lengths and circumferences. Typically the filter length will be from about <NUM>, associated with short, regular formats, to <NUM>, associated with ultra-long super-slim formats. The tipping paper will have a greater length than the filter, for example from <NUM> to <NUM> longer, such that the tipping paper covers the filter and overlaps the tobacco rod to connect the filter to the tobacco rod.

Smoking articles and filter units described herein can be made in, but are not limited to, any of the above formats.

The filter material forming any of the filter units or other filter components described herein can comprise cellulose acetate fibre tow. The filter material can also be formed using other materials used to form fibres, such as polyvinyl alcohol (PVOH), polylactic acid (PLA), polycaprolactone (PCL), poly(<NUM>-<NUM> butanediol succinate) (PBS), poly(butylene adipate-co-terephthalate)(PBAT), starch based materials, paper, cotton, aliphatic polyester materials and polysaccharide polymers or a combination thereof. The filter material may be plasticised with a suitable plasticiser for the filter material, such as triacetin where the filter material is cellulose acetate tow, or may be non-plasticised. The tow used to produce the filter unit or other filter component can use any suitable specification, such as fibres having a 'Y' shaped or other cross section, filamentary denier values between <NUM> and <NUM> denier per filament, for example between <NUM> and <NUM> denier per filament and total denier values of <NUM>,<NUM> to <NUM>,<NUM>, for example between <NUM>,<NUM> and <NUM>,<NUM>.

As used herein, the terms "flavour" and "flavourant" refer to materials which, where local regulations permit, may be used to create a desired taste or aroma in a product for adult consumers. They may include extracts (e.g., liquorice, hydrangea, Japanese white bark magnolia leaf, chamomile, fenugreek, clove, menthol, Japanese mint, aniseed, cinnamon, herb, wintergreen, cherry, berry, peach, apple, Drambuie, bourbon, scotch, whiskey, spearmint, peppermint, lavender, cardamom, celery, cascarilla, nutmeg, sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil, orange oil, cassia, caraway, cognac, jasmine, ylang-ylang, sage, fennel, piment, ginger, anise, coriander, coffee, or a mint oil from any species of the genus Mentha), flavour enhancers, bitterness receptor site blockers, sensorial receptor site activators or stimulators, sugars and/or sugar substitutes (e.g., sucralose, acesulfame potassium, aspartame, saccharine, cyclamates, lactose, sucrose, glucose, fructose, sorbitol, or mannitol), and other additives or substances such as charcoal, chlorophyll, minerals, botanicals, or breath freshening agents. They may be imitation, synthetic or natural ingredients or blends thereof. They may be in any suitable form, for example, oil, liquid, or powder.

In the figures described herein, like reference numerals are used to illustrate equivalent features, articles or components.

<FIG> is a side-on cross sectional view of a first filter unit 1including a tube <NUM>, formed from filter material in the present example, and forming part of a smoking article <NUM>. The smoking article <NUM> has a mouth end 3a, arranged to be placed in the user's mouth when smoking, and a lit end 3b, arranged to be lit when smoking. The filter unit <NUM> is connected to an aerosol generating material <NUM>, in the present case cut tobacco in the form of a rod, by a tipping paper <NUM>. The aerosol generating material <NUM> is wrapped in a wrapper <NUM>, for instance cigarette paper.

The tube <NUM> comprises a wall having inner and outer surfaces which are substantially circular in cross section, in the present example, for cross sections taken along the longitudinal length of the tube. An inner diameter of the tube <NUM> is defined between two diametrically opposite points on the inner surface of the wall, while an outer diameter of the tube <NUM> is defined between two diametrically opposite points on the outer surface of the wall. The wall of the tube <NUM> may have a thickness in the range of about <NUM> to about <NUM>. For example, the wall may have a thickness of between about <NUM> and about <NUM>, between about <NUM> and about <NUM> or between about <NUM> and about <NUM>, or about <NUM>.

The tube <NUM> has a first portion 2a and a second portion 2b. In <FIG>, these portions 2a, 2b are disposed longitudinally along the length of the tube <NUM>. As shown in <FIG>, the first and second portions 2a, 2b are arranged either side of a longitudinal position on the tube indicated by dashed line 'X'. The first portion 2a of the tube <NUM> extends from an end of the tube <NUM> furthest from the mouth end 3a of the smoking article <NUM> up to the dashed line 'X', and the second portion 2b of the tube <NUM> extends from the dashed line 'X' to the mouth end 3a of the smoking article. An inner diameter of the first portion 2a of the tube <NUM> is different from an inner diameter of the second portion 2b of the tube <NUM>. The second portion 2b is at a distal end of the filter unit, in particular at the mouth end 3a of the smoking article <NUM> in the present example.

In the present example, an inner diameter of the second portion 2b, illustrated in <FIG> by arrow 'B', is greater than an inner diameter of the first portion 2a, illustrated by arrow 'A'. The inner diameter 'A' of the first portion 2a can be in the range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. For example, the inner diameter of the first portion 2a may be about <NUM>. The inner diameter 'B' of the second portion 2b varies along the length of the second portion 2b in the present example. The largest inner diameter 'B' of the second portion 2b can be in the range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. For example, the largest inner diameter 'B' of the second portion 2b may be about <NUM>.

The overall length of the tube <NUM> may be in the range of about <NUM> to about <NUM>, or about <NUM> to about <NUM>. For example, the length of the tube <NUM> may be about <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM>.

The length of the first portion 2a may be in the range of about <NUM> to about <NUM>, or about <NUM> to about <NUM>. For example, the length of the first portion 2a may be about <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM>.

The length of the second portion 2b may be in the range of about <NUM> to <NUM>. For example, the length of the second portion 2b may be about <NUM> to about <NUM>, about <NUM> to about <NUM> or about <NUM>.

The second portion 2b may be formed by indenting the filter material at the end of the tube <NUM> closest to the mouth end 3a of the smoking article. Alternatively, the second portion 2b may be formed by cutting the end of the tube <NUM> to remove filter material from the end of the tube <NUM>.

In the present example, the outer diameter of the second portion 2b is the same as the outer diameter of the first portion 2a.

In the present example, each of the first portion 2a and the second portion 2b has a first end and a second end. The second end of the first portion 2a adjoins the first end of the second portion 2b, and has an inner diameter substantially the same as the first end of the second portion 2b.

The tube <NUM> has a longitudinal axis (not shown). The inner surface of the first portion 2a is substantially parallel to the longitudinal axis of the tube <NUM>. The inner surface of the second portion 2b is chamfered in that it is at an angle to the longitudinal axis of the tube <NUM>, in the present example. The inner diameter of the second portion 2b decreases with distance from a distal end, for instance the mouth end 3a, of the filter unit. The angle of intersection between a straight line following the inner surface of the second portion 2b of the tube <NUM> and the longitudinal axis of the tube <NUM> may be in the range of about <NUM>° to about <NUM>°, or about <NUM>° to about <NUM>°, or about <NUM>° to about <NUM>°. For example, the angle may be about <NUM>°.

Although a tube <NUM> having a uniformly chamfered inner edge has been described with reference to <FIG>, other tube shapes can be used. For instance, the second portion 2b of the tube <NUM> can have an inner diameter 'B' which is uniform along the length of the second portion 2b, and therefore forms a step at the location shown by line 'X' between the first and second portions 2a, 2b. Alternatively or in addition, a chamfer or step as described in respect of the inner diameter of the second portion 2b of the tube <NUM> may be provided in the outer diameter of the second portion 2b of the tube <NUM>. <FIG> illustrates an outer chamfered tube <NUM>' which can be used in place of the tube <NUM> used in the smoking article <NUM> of <FIG>, in which a chamfer is provided on an outer edge of the tube <NUM>' such that an outer diameter of the second portion 2b', illustrated in <FIG> by arrow 'D', is smaller than an outer diameter of the first portion 2a', illustrated by arrow 'C'. The tube <NUM>' has a longitudinal axis (not shown). The outer surface of the first portion 2a' is substantially parallel to the longitudinal axis of the tube <NUM>'. The outer surface of the second portion 2b' is chamfered in that it is at an angle to the longitudinal axis of the tube <NUM>', in the present example. The angle of intersection between a straight line following the outer surface of the second portion 2b' of the tube <NUM>' and the longitudinal axis of the tube <NUM>' may be in the range of about <NUM>° to about <NUM>°, or about <NUM>° to about <NUM>°, or about <NUM>° to about <NUM>°. For example, the angle may be about <NUM>°.

Referring again to <FIG>, in the present example, the first filter unit <NUM> further includes a sleeve <NUM>. The sleeve <NUM> is formed from a sheet material such as plug wrap. In alternative examples, the sleeve <NUM> can be formed in other ways, for instance from plastic or other materials.

The first filter unit <NUM> also includes an upstream filter segment <NUM>, arranged upstream of the tube <NUM> in the direction of mainstream smoke when the smoking article is drawn on by a user. The upstream filter segment <NUM> has a longitudinal axis (not shown). The upstream filter segment <NUM> has a curved outer surface 8a circumscribing the segment <NUM>, a first longitudinal end surface 8a closest to the lit end 3a of the smoking article <NUM> and a second longitudinal end surface 8b closest to the mouth end 3a of the smoking article <NUM>. The longitudinal end surfaces 8a, 8b are perpendicular to the longitudinal axis of the upstream filter segment <NUM>. In the present example, the tube <NUM> and the upstream filter segment <NUM> have a common longitudinal axis.

The sleeve <NUM> is wrapped around the tube <NUM> and the upstream filter segment <NUM>. In the present example, an adhesive is provided between the sleeve <NUM> and the tube <NUM> and upstream filter segment <NUM> and in this way the sleeve <NUM> connects the tube <NUM> to the upstream filter segment <NUM>.

In the present example, the end of the tube <NUM> closest to the mouth end 3a of the smoking article <NUM> is flush with the end of the sleeve <NUM> closest to the mouth end 3a of the smoking article <NUM>. However, in alternative examples, the tube <NUM> may extend beyond the end of the sleeve <NUM> closest to the mouth end 3a of the smoking article <NUM>, or may stop short of the end of the sleeve <NUM> closest to the mouth end 3a of the smoking article <NUM>. For instance, when the outer chamfered tube <NUM>' of <FIG> is used in place of the tube <NUM> of <FIG>, the sleeve <NUM> may surround only the first portion 2a' of the tube <NUM>', and the tipping <NUM> can also extend up to the edge of the sleeve <NUM> closest to the mouth end 3a of the smoking article <NUM>. In this way, the smoking article <NUM> can be provided with an outer chamfered edge at the mouth end 3a giving a smooth surface against which the users lips can be placed, facilitating the user in holding the smoking article in their mouth. In the present example, the sleeve <NUM> fully surrounds the outer surface of the upstream filter segment <NUM>.

The length of the upstream filter segment <NUM> may be selected according to the desired filtration performance of the filter unit <NUM>, and may be in the range <NUM> to <NUM>, or <NUM> to <NUM>. For example, the length of the upstream filter segment <NUM> may be about <NUM>.

The outer diameter of the upstream filter segment <NUM> may be substantially the same as the outer diameter of the tube <NUM>. Either or both of the tube <NUM> and the upstream filter segment may comprise a separate plug wrap (not shown) around which the sleeve <NUM> is wrapped.

The tube <NUM> and upstream filter segment <NUM> may be formed of filter material, in particular a fibrous filter material. The tube <NUM> and/or upstream filter segment <NUM> can contain substances such as additives or agents for modifying the aerosol, in the present case smoke, generated by the smoking article <NUM>. For example, a frangible capsule (not shown) containing a flavourant or other additive or substance such as water may be located within the upstream filter segment <NUM>. The capsule can be located at a central longitudinal position within the upstream filter segment <NUM>, or may be offset from the central longitudinal position.

The capsule has a liquid centre and a frangible outer shell which can be broken by a user by squeezing the filter unit <NUM>, to thereby release the flavourant. The flavourant is transferred to the aerosol generated by the smoking article <NUM> as the smoking article <NUM> is smoked by the user.

In alternative examples, the first filter unit <NUM> may include alternative substances such as additives or agents for modifying the aerosol generated by the smoking article <NUM>, such as granules of activated carbon or other adsorbents, humectants, diluents etc..

The smoking article <NUM> can be a cigarette in any of the smoking article formats described herein.

<FIG> is a side-on cross sectional view of a filter insert <NUM> for use with the filter unit of <FIG>. The filter insert <NUM> includes a cylindrical element <NUM> formed from cellulose acetate tow wrapped in a sleeve <NUM>, in the present case a plug wrap. The filter insert <NUM> may be inserted into the hollow centre of the tube <NUM> of the smoking article <NUM> by a user, for instance such that the insert <NUM> abuts the second longitudinal end surface 8b of the upstream filter segment <NUM>. The filter insert <NUM> may include a smoke modifying substance allowing the user to alter properties of the aerosol passing through the smoking article <NUM> when the smoking article <NUM> is smoked and the filter insert <NUM> is inserted into the tube <NUM>. The inner chamfer in the second portion 2b of the tube <NUM> can facilitate insertion of the filter insert <NUM> into the tube <NUM> and, for instance, enable the outer diameter of the filter insert <NUM> to be substantially the same as the inner diameter 'A' of the tube <NUM>, which would otherwise make insertion of the insert <NUM> into the tube difficult.

<FIG> is a side-on cross sectional view of a discrete second filter unit <NUM> including a tube <NUM> formed from filter material and provided as a separate unit <NUM> for use with a smoking article <NUM>. The second filter unit <NUM> can be attached onto the mouth end 17a of the smoking article <NUM> by a user. The second filter unit <NUM> is configured to modify one or more properties of an aerosol, such as smoke, which is generated by the smoking article <NUM>. The second filter unit <NUM> has a mouth end 16a arranged to be inserted into a user's mouth when the second filter unit <NUM> is attached to the smoking article <NUM>.

The tube <NUM> of the second filter unit <NUM> is generally similar in design to the tube <NUM> of the first filter unit <NUM> illustrated in <FIG>, and corresponding features and dimensions apply except where alternatively stated below.

The tube <NUM> has a first portion 16a and a second portion 15b. These portions 16a, 16b are the portions of the tube <NUM> either side of a longitudinal position on the tube indicated in <FIG> by dashed line 'X'. The first portion 16a of the tube <NUM> extends from an end of the tube <NUM> closest to the mouth end 16a of the second filter unit <NUM> up to the dashed line 'X', and the second portion 16b of the tube <NUM> extends from the dashed line 'X' to the edge of the tube <NUM> furthest from the mouth end 16a of the filter unit. An inner diameter of the first portion 16a of the tube <NUM> is different from an inner diameter of the second portion 16b of the tube <NUM>.

In the present example, an inner diameter of the second portion 16b, illustrated in <FIG> by arrow 'B', is greater than an inner diameter of the first portion 16a, illustrated by arrow 'A'. The inner diameter 'A' of the first portion 16a may be in the range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. For example, the inner diameter of the first portion 16a may be about <NUM>. Inner diameter of the first portion may be selected to correspond to the outer diameter of the mouth end 17a of the smoking article <NUM>. The inner diameter 'B' of the second portion 16b varies along the length of the second portion 16b in the present example. The largest inner diameter 'B' of the second portion 16b can be in the range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. For example, the largest inner diameter 'B' of the second portion 2b may be about <NUM>.

In the present example, the outer diameter of the second portion 16b is the same as the outer diameter of the first portion 16a.

In the present example, the second filter unit <NUM> further includes a sleeve <NUM>. The sleeve <NUM> is formed from a sheet material such as plug wrap. In alternative examples, the sleeve <NUM> can be formed in other ways, for instance from plastic or other materials.

The second filter unit <NUM> also includes a downstream filter segment <NUM>, arranged downstream of the tube <NUM> in the direction of mainstream smoke when the smoking article <NUM> is drawn on by a user with the second filter unit <NUM> attached to the smoking article <NUM>. The downstream filter segment <NUM> has a longitudinal axis (not shown). The downstream filter segment <NUM> has a longitudinal end surface 19a furthest from the mouth end 16a of the second filter unit <NUM>. In the present example, the tube <NUM> and the downstream filter segment <NUM> have a common longitudinal axis.

The sleeve <NUM> is wrapped around the tube <NUM> and the downstream filter segment <NUM>. In the present example, an adhesive is provided between the sleeve <NUM> and the tube <NUM> and downstream filter segment <NUM> and in this way the sleeve <NUM> connects the tube <NUM> to the downstream filter segment <NUM>.

In the present example, the end of the tube <NUM> furthest from the mouth end 16a of the second filter unit <NUM> extends beyond the end of the sleeve <NUM> furthest from the mouth end 16a of the second filter unit <NUM>. In the present example, the tube <NUM> extends <NUM> beyond the sleeve <NUM>. However, in alternative examples, the tube <NUM> may extend between about <NUM> and <NUM>, for instance between about <NUM> and <NUM> beyond the end of the sleeve <NUM> furthest from the mouth end 16a of the second filter unit <NUM>, or may be flush with the edge of the sleeve <NUM> or stop short of the end of the sleeve <NUM> furthest from the mouth end 16a of the filter element <NUM>. In the present example, the sleeve <NUM> fully surrounds the outer surface of the downstream filter segment <NUM>.

The length of the downstream filter segment <NUM> may be selected according to the desired filtration performance of the second filter unit <NUM>, and may be in the range <NUM> to <NUM>, or <NUM> to <NUM>. For example, the length of the downstream filter segment <NUM> may be about <NUM>.

The outer diameter of the downstream filter segment <NUM> may be substantially the same as the outer diameter of the tube <NUM>. Either or both of the tube <NUM> and the downstream filter segment <NUM> may comprise a separate plug wrap (not shown) around which the sleeve <NUM> is wrapped.

The tube <NUM> and downstream segment <NUM> may be formed of filter material, in particular a fibrous filter material, as described herein. The tube <NUM> and/or downstream segment <NUM> can contain substances such as additives or agents for modifying the aerosol, in the present case smoke, generated by the smoking article <NUM>. For example, a frangible capsule (not shown) as described elsewhere herein and containing a flavourant or other additive may be located within the downstream filter segment <NUM>. The capsule can be located at a central longitudinal position within the downstream filter segment <NUM>, or may be offset from the central longitudinal position.

In alternative examples, the second filter unit <NUM> may include alternative substances such as additives or agents for modifying the aerosol generated by the smoking article <NUM>, such as granules of activated carbon or other adsorbents, humectants, diluents etc..

The smoking article <NUM> can be a conventional cigarette in any of the smoking article formats described herein.

The discrete second filter unit <NUM> can be coupled or attached to the smoking article <NUM> by a user. In the present example, the tube <NUM> of the second filter unit <NUM> is arranged to receive a mouth end portion 17a of the smoking article <NUM> so that the second filter unit <NUM> and the smoking article <NUM> can be attached or coupled together by a user. The mouth end 17a of the smoking article <NUM>, in the present example, abuts the longitudinal end surface 19a when the second filter unit <NUM> is connected to the smoking article <NUM>. The user can select whether or not to attach the second filter unit <NUM> to the smoking article <NUM> prior to smoking the smoking article <NUM>, and can in this way control the length of filter of the smoking article <NUM> and therefore the level of filtration of the aerosol generated by the smoking article <NUM>, as well as any other modification of the aerosol performed by the second filter unit <NUM>.

The second filter unit <NUM> may be attached to the smoking article <NUM> in any suitable way. This may include forming an interference fit between an inner surface of the tube <NUM> and an outer surface of the smoking article <NUM>. In this case, the interference fit is such that a seal is formed at the interface between the inner surface of the tube <NUM> and the outer surface of the smoking article <NUM>, which inhibits the ingress of gases (such as air) that would normally enter into the smoking article <NUM> via a gap between the outer surface of the smoking article <NUM> and the inner surface of the tube <NUM>. The amount of air entering into a smoking article between the two neighbouring surfaces may be variable and/or unwanted. Restricting the ingress of air therefore provides a degree of control of the airflow into and/or through the smoking article <NUM>.

The tube <NUM> has a longitudinal axis (not shown). The inner surface of the first portion 16a is substantially parallel to the longitudinal axis of the tube <NUM>. The inner surface of the second portion 16b is chamfered in that it is at an angle to the longitudinal axis of the tube <NUM>, in the present example. The angle of intersection between a straight line following the inner surface of the second portion 16b of the tube <NUM> and the longitudinal axis of the tube <NUM> may be in the range of about <NUM>° to about <NUM>°, or about <NUM>° to about <NUM>°, or about <NUM>° to about <NUM>°. For example, the angle may be about <NUM>°.

In the present example, the inner portion of the edge of the tube <NUM> furthest from the mouth end 16a of the second filter unit <NUM> is chamfered such that an inner diameter of the second portion 16b, illustrated by arrow 'B' is greater than an inner diameter of the first portion 16a, illustrated by arrow 'A'. This arrangement makes it easier for the user to insert an end 17a of the smoking article <NUM> into the tube <NUM>, in order to couple the second filter unit <NUM> to the smoking article <NUM>.

<FIG> is a side-on cross sectional view of a third filter unit <NUM> forming part of a smoking article <NUM>. The third filter unit <NUM> comprises a body <NUM> formed of filter material. The smoking article <NUM> includes a rod of aerosol generating material <NUM>, in the present case cut tobacco, wrapped in a sheet material <NUM>, in the present case cigarette paper. The rod <NUM> and third filter unit <NUM> are connected by tipping <NUM> which surrounds the third filter unit <NUM> and partially surrounds the rod <NUM>. The smoking article <NUM> has a mouth end 21a to be inserted in the user's mouth when smoking. The body <NUM> of the third filter unit <NUM> has an end surface <NUM> at the end of the body <NUM> closest to the mouth end 21a of the smoking article <NUM> furthest from the rod <NUM> and a recess <NUM> formed in the end surface <NUM>. The recess <NUM> is a hollow depression in the body <NUM>. The recess <NUM> extends into, but not entirely through, the body <NUM>. In the present example, the body <NUM> is cylindrical, and the end surface <NUM> is a longitudinal end surface of the body <NUM>.

In the present example, the recess <NUM> has the shape of a conical frustum, and has an inner base surface 27a and an inner side surface 27b. In other examples, the recess <NUM> may have the shape of other frustums, and may have multiple side surfaces. Alternatively, the recess may be cylindrical, conical or hemispherical in shape.

The recess <NUM> may be formed in the filter material of the body <NUM> by indentation. In this case, the filter material of the body <NUM> may be compressed during formation of the recess <NUM>. In other words, the filter material at or close to an inner surface of the recess <NUM> is denser than the filter material in other areas of the body <NUM>, such as the end of the body <NUM> furthest from the longitudinal end surface <NUM>. Alternatively, the recess <NUM> can be formed by removing filter material from the body <NUM> at the end surface <NUM>. The recess <NUM> can direct smoke to a particular portion of the body <NUM> in which the recess <NUM> is located, by reducing the volume of material in that part of the body <NUM>, and enable particular formations of smoke from the mouth end 21a of the smoking article <NUM>.

The body <NUM> may include a smoke modifying substance /additive (not shown) disposed within the filter material of the body <NUM>. The smoke modifying substance/additive may be any smoke modifying substance/additive, such as flavours or other additives, as described herein.

The third filter unit <NUM> may further include a sleeve <NUM>, such as plug wrap, which is wrapped around the body <NUM>. In the present example, the body <NUM> is flush at the mouth end 21a of the smoking article with the edge of the sleeve <NUM>. In other examples, the sleeve <NUM> and/or tipping <NUM> may extend beyond an end of the body <NUM>. The space thus formed by the sleeve <NUM> and/or tipping <NUM> extending beyond an end of the body <NUM>, such as the longitudinal end surface <NUM>, may be arranged to receive a filter insert, such as that illustrated in <FIG>.

<FIG> is an end-on view of the third filter unit <NUM>. <FIG> is an end-on view of another design for a third filter unit <NUM>', in this case having a triangular shaped recess having an inner base surface 27a' and inner side surfaces 27b' and longitudinal end surface <NUM>'. <FIG> is an end-on view of another design for a third filter unit <NUM>", in this case having a hexagonal shaped recess having an inner base surface 27a" and inner side surfaces 27b" and longitudinal end surface <NUM>".

The third filter units <NUM>, <NUM>', <NUM>" described herein having a recess formed in an end surface can be used to form components of other filter units and filter inserts described herein. For instance, the third filter units <NUM>, <NUM>', <NUM>" described herein having a recess formed in an end surface can be used as the upstream filter segment <NUM> of the first filter unit <NUM> described with reference to <FIG>, as the filter insert <NUM> as described with reference to <FIG>, or as the downstream filter segment <NUM> of the second filter unit <NUM> described with reference to <FIG>. In each case, the recess would be arranged to face the mouth end of the product.

<FIG> is a side-on cross sectional view of a fourth filter unit <NUM>, including a tube <NUM> formed from sheet material, and provided as a discrete component for use with a separate smoking article <NUM> as described with reference to <FIG>. The fourth filter unit <NUM> has a mouth end 30a and comprises a tube <NUM> having a first portion 31a and a second portion 31b. An inner diameter of the first portion 31a is different from an inner diameter of the second portion 31b. The fourth filter unit <NUM> also includes a downstream filter plug <NUM> arranged closer to the mouth end 30a of the filter unit <NUM> than the tube <NUM> and formed from filter material. The fourth filter unit <NUM> further comprises a sleeve <NUM> partially surrounding the tube <NUM> and surrounding the downstream filter plug <NUM>. The tube <NUM> of the present example can be formed from a sheet material such as paper, card, cardboard, plastic or similar materials.

The fourth filter unit <NUM> can be coupled or attached to another tobacco industry product, such as smoking article <NUM>, by a user. The tube <NUM> is arranged to receive a portion of the smoking article <NUM>, for instance the mouth end 17a of the smoking article <NUM>, so that the filter unit <NUM> and the smoking article <NUM> can be attached or coupled together by a user. The fourth filter unit <NUM> is configured to modify one or more properties of an aerosol, such as smoke, which is generated by the smoking article <NUM>.

In the present example, the tube <NUM> is formed from a sheet material separate from the sleeve <NUM>, enabling the tube <NUM> to be formed of stiffer material than may be possible for use in wrapping the downstream filter plug <NUM>. An inner diameter 'B' of the second portion 31b is greater than an inner diameter 'A' of the first portion 31a. This arrangement makes it easier for the user to couple the fourth filter unit <NUM> to the smoking article <NUM>. In the present example, an outer diameter 'B' of the second portion 31b is greater than an outer diameter of the first portion 31a. This arrangement may be referred to as the tube <NUM> having a 'widened end'. The dimensions of the tube <NUM> of <FIG> can correspond to the dimensions of the tube <NUM> described with reference to <FIG>.

The tube <NUM> formed from sheet material described with reference to <FIG> can be used in place of the tube <NUM> at the mouth end of the smoking article <NUM> described with reference to <FIG>.

<FIG> are perspective views of an apparatus <NUM> for shaping a tobacco industry product <NUM>. The tobacco industry product <NUM> may be (for example) a smoking article, a filter, or a tube, or other components described herein. The filter may be an individual filter unit, or may be part of a smoking article. The tube may be part of another tobacco industry product, e.g. a filter unit or a smoking article. Any of these tobacco industry products <NUM> may have a longitudinal axis. Any of these tobacco industry products may have a longitudinal end surface. Tubular components may also have an inner surface around the inside of the tube. The apparatus <NUM> can be used, for instance, to form any of the tubes <NUM>, <NUM>', <NUM>, <NUM> of the first, second and fourth filter units <NUM>, <NUM>, <NUM> described herein, or the recess <NUM> formed in the filter body <NUM> of the third filter unit <NUM> described herein.

Referring to <FIG>, the apparatus <NUM> comprises a shaping head <NUM> configured to change the shape of a first end of the tobacco industry product <NUM> (not shown in this Figure). The apparatus <NUM> further comprises an actuator arrangement <NUM> configured to move the shaping head <NUM> and/or tobacco industry product <NUM>. The actuator arrangement <NUM> is configured to move the shaping head <NUM> and/or tobacco industry product <NUM> in a direction substantially parallel to a longitudinal axis of the tobacco industry product <NUM> such that the shaping head <NUM> is brought into contact with a first end 41a of the tobacco industry product <NUM> in order to change the shape of the first end 41a.

Alternatively or in addition to the above, the actuator arrangement <NUM> can be configured to move the shaping head <NUM> and/or tobacco industry product <NUM> such that the shaping head <NUM> is brought into contact with a first longitudinal end surface and/or an inner surface of the tobacco industry product <NUM> in order to change the shape of the first longitudinal end surface and/or an inner surface.

In some examples, a receiving unit is arranged to receive and grip the tobacco industry product <NUM>, so as to hold tobacco industry product <NUM> in position while it is shaped. This may be achieved by mechanical means, such as a clamp, or alternatively by means such as vacuum suction, as described in more detail below.

In use, when the shaping head <NUM> is brought into contact with the first end 41a of the tobacco industry product <NUM>, the pressure exerted on the end 41a of the tobacco industry product <NUM> by the shaping head <NUM> deforms the material of the tobacco industry product <NUM>, thereby changing a shape of the end of the tobacco industry product <NUM>. Changing the shape of the end of the tobacco industry product <NUM> may, for instance, include changing an inner and/or outer diameter of the tobacco industry product <NUM>, as well as forming an indentation in the end 41a.

The actuator arrangement <NUM> may be configured to move the shaping head <NUM> and/or tobacco industry product <NUM> in a reciprocating fashion. In other words, actuator arrangement <NUM> may be configured to move the shaping head <NUM> and/or tobacco industry product <NUM> so that they are first brought into contact with each other and are then moved apart from each other.

The shaping head <NUM> may be cylindrical in shape. In the present example, the shaping head <NUM> is substantially cylindrical in shape, and the end of the shaping head <NUM> has a chamfered profile. In other words, the shaping head <NUM> comprises a surface which is angled with respect to a side surface and a longitudinal end surface thereof.

In other exemplary arrangements, the shaping head <NUM> may be conical in shape. The shaping head <NUM> may have the shape of a frustum, such as a conical frustum. The shaping head <NUM> may be hemispherical in shape or may have a shape which has relatively low orders of rotational symmetry or no rotational symmetry. For instance, when forming the third filter units <NUM>' and <NUM>" of <FIG> herein, the end of the shaping head <NUM> would have a triangular frustum shape with order <NUM> rotational symmetry or a hexagonal frustum shape with order <NUM> rotational symmetry. The shaping head <NUM> can have, for instance, order <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or infinite/continuous rotational symmetry.

In the present example, the shaping head <NUM> has a longitudinal axis (not shown). The apparatus <NUM> is configured to rotate the shaping head <NUM> about its longitudinal axis, for instance for shaping heads <NUM> having infinite/continuous rotational symmetry. Rotating the shaping head <NUM> when the shaping head <NUM> is brought into contact with the end of the tobacco industry product <NUM> can provide a more even change in the shape of the end of the tobacco industry product <NUM>, resulting in a uniform end profile, compared to a fixed shaping head <NUM>. However, the apparatus <NUM> can be configured such that the shaping head <NUM> is fixed when the shaping head <NUM> has an order of symmetry less than infinite, for instance order <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> rotational symmetry. A known method of applying a shape to a filter which is visible from the mouth end of the filter is to create a tube filter having that shape running through the centre as a bore. However, in such cases, the standard cigarette making process requires such a shape to have at least order <NUM> rotational symmetry, otherwise the shape will not be the same when the tube is used in different orientations. The use of a shaping head <NUM> which can be applied directly to a filter body addresses this issue, meaning that shapes with order <NUM> rotational symmetry can be applied uniformly to cigarette filters.

<FIG> are side-on cross sectional and end-on views of respective first, second and third shaping heads <NUM>, <NUM>' and <NUM>" for use with the apparatus of <FIG>. The first shaping head <NUM>, illustrated in <FIG>, comprises a conical frustum shape, and can be used to form the third filter unit <NUM> of <FIG>. The second shaping head <NUM>', illustrated in <FIG>, comprises a triangular frustum shape, and can be used to form the third filter unit <NUM>' of <FIG>. The third shaping head <NUM>", illustrated in <FIG>, comprises a hexagonal frustum shape, and can be used to form the third filter unit <NUM>" of <FIG>.

The apparatus <NUM> may be configured so that, in use, the longitudinal axis of the shaping head <NUM> and the longitudinal axis of the tobacco industry product <NUM> are aligned. In such an arrangement, the shaping head <NUM> and the tobacco industry product <NUM> may be said to have a common longitudinal axis.

In the present example, the apparatus <NUM> comprises a drum <NUM> arranged to move the tobacco industry product <NUM> relative to the shaping head <NUM> in order to bring the shaping head <NUM> into contact with an end of the tobacco industry product <NUM>.

The drum <NUM>, in the present example, is provided as a modification to the known separator drum used in cigarette manufacture to separate first and second tobacco rods so that a filter can be placed between the tobacco rods and the rods and filter can then be wrapped in tipping paper. The drum <NUM> is modified to include a head support unit <NUM> which supports a plurality of shaping heads <NUM> arranged such that they are spaced circumferentially around the drum <NUM>. The longitudinal axis of each of the shaping heads <NUM> is parallel to the axis of rotation of the drum <NUM>. The drum <NUM> includes a plurality of moving plates <NUM> in each of which first and second product receiving units or regions <NUM> are provided, in the form of flutes <NUM> in the present example. Each flute <NUM> is arranged to receive a tobacco industry product <NUM> and is generally shaped as an elongate groove formed in the plate <NUM> within which the tobacco industry product <NUM> can sit. The tobacco industry products <NUM> are held within the flutes <NUM> by suction through apertures formed in the base of the flutes <NUM>, as known in conventional separator and similar drums.

In the present example, the moving plates <NUM> move in a reciprocating manner towards and away from the shaping heads <NUM> held by the head support member <NUM> in order to bring tobacco industry products <NUM> into contact with the shaping heads <NUM>. In an alternative exemplary arrangement, the apparatus <NUM> may be configured so that both the plates <NUM> and the head support unit <NUM> are arranged to move in use, or so that only the head support unit <NUM> moves, in order to bring the shaping heads <NUM> into contact with the end of the tobacco industry product <NUM>. Should additional force be required to hold the tobacco industry products <NUM> within the product receiving regions <NUM> provided in the plates <NUM>, then these can be adapted to include an alternative gripping arrangement. Alternatively or additionally, a swash-plate type arrangement can be used to push tobacco industry products <NUM> longitudinally from the end opposite to the end which is to be shaped.

The apparatus <NUM> may further comprise a heating element <NUM> which is arranged to heat the shaping heads <NUM>. When the shaping heads <NUM> are heated during contact with the end of the tobacco industry product <NUM>, the heat may deform the material of the tobacco industry product <NUM>, which aids in changing the shape of the end of the tobacco industry product <NUM>. The heating element may be an induction coil. Alternatively, the shaping head <NUM> may be heated by a hot air system or a direct thermocouple.

As shown in <FIG>, a gearing mechanism <NUM> can be used to rotate the shaping heads <NUM>, in the form of mandrels in the present example. Each mandrel <NUM> extends into a base shaft 42a which extends into and is supported by the head support unit <NUM>. In particular, the head support unit <NUM> includes first and second bearings 44a, 44b which support the base shaft 42a of each mandrel <NUM>, allowing it to rotate. Each mandrel base shaft 42a is also connected to and arranged to be turned via a mandrel driving cog 48a which in turn meshes with a fixed cog 48b extending around the periphery of the drum <NUM> and fixed in relation to the head support unit <NUM>. As the outer portions of the drum <NUM> rotate, including the head support unit <NUM>, this causes the mandrel driving cog 48a for each mandrel <NUM> to rotate as its teeth mesh with the fixed cog 48b, and this rotates the mandrel <NUM>. Other arrangements for turning the shaping heads <NUM> can also be used, such as a separate motor arrangement for rotating one or more of the heads <NUM>. The mandrel driving cogs 48a can be removed from the mandrel base shafts 42a of the mandrels <NUM> in order to provide fixed rather than rotating mandrels <NUM>.

In an alternative exemplary arrangement, the apparatus <NUM> may further comprise a second shaping head (not shown) which is substantially the same as the shaping head <NUM> described above, and is arranged to change the shape of a second end of the tobacco industry product <NUM>. In this arrangement, the apparatus <NUM> can shape both ends of the tobacco industry product <NUM>, either simultaneously or in sequence.

Also presented herein is a method of shaping a tobacco industry product. The method is shown in <FIG> and comprises the steps of: providing a tobacco industry product (S101); and changing the shape of a first end of the tobacco industry product by moving a shaping head and/or the tobacco industry product in a direction substantially parallel to a longitudinal axis of the tobacco industry product such that the shaping head is brought into contact with the first end of the tobacco industry product (S102).

Claim 1:
A filter unit (<NUM>) for a smoking article comprising:
a tube (<NUM>) having a first portion (16a) and a second portion (16b), wherein the second portion is at a distal end of the filter unit, and an inner diameter of the first portion is different from an inner diameter of the second portion;
a downstream filter plug (<NUM>) arranged closer to the mouth end of the filter unit (<NUM>) than the tube (<NUM>) and formed from filter material; and
a sleeve (<NUM>) partially surrounding the tube (<NUM>) and surrounding the downstream filter plug (<NUM>),
wherein the inner diameter of the second portion decreases with distance from the distal end of the filter unit, and
wherein an outer diameter of the first portion (16a) is substantially the same as an outer diameter of the second portion (16b).