GB2575427A

GB2575427A - A Filter

Info

Publication number: GB2575427A
Application number: GB1808057.2A
Authority: GB
Inventors: Kaljura Karl
Original assignee: British American Tobacco Investments Ltd
Current assignee: British American Tobacco Investments Ltd
Priority date: 2018-05-17
Filing date: 2018-05-17
Publication date: 2020-01-15
Also published as: GB201808057D0

Abstract

A filter 30 for a tobacco industry product comprises: a first section 2 and a second section 3 joined end-to-end to extend coaxially along a longitudinal axis, the first section 2 being downstream of the second section 3; the first section 2 comprises a first flow duct 5a-c extending therethrough and offset from the longitudinal axis and having a first cross-sectional area; and the second section 3 comprises a second flow duct 6 extending therethrough and offset from the longitudinal axis and having a second cross-sectional area, larger than the first cross-sectional area; wherein the first 2 and second 3 sections are movable relative to each other to align the first 5a-c and second 6 flow ducts and form a continuous flow path 7 extending through both sections 2, 3. The first 5a-c and second 6 flow ducts may comprise a plurality of flow ducts, and the flow ducts 5a-c, 6 in each section 2, 3 may be cylindrical or arcuate. The first section 2 may be rotatable relative to the second section 3. The first 2 and/or second 3 section may be formed from filtration material, and the first 5a-c and/or second 6 flow duct may comprise a filtration material and/or a flavourant.

Description

Α Filter

Technical Field

The present invention relates to a filter. The present invention also relates to a tobacco 5 industry product comprising the filter.

Background

It is known that the structure of a filter for a tobacco industry product has an effect on the flow resistance experienced by a consumer when drawing a gaseous flow towards a 10 mouth end of the smoking article. A variety of filters have been designed such that the gaseous flow is drawn through either slowly, billowing out of the filter, or quickly, such that a stream of smoke flows further into the user’s mouth. The flow resistance, and therefore flow speed, affects the taste intensity and smoke amplitude delivered to the consumer.

Different consumers prefer different taste intensities and smoke amplitudes, or a single consumer may enjoy a range of them, and so filters are known in which the consumer can vary the flow resistance to suit their preference. However, such filters often have a narrow range of flow resistances and/or high flow resistance such that they provide a 20 low taste intensity and low smoke amplitude.

Summary of the Invention

In accordance with the embodiments described herein, there is provided a filter for a tobacco industry product comprising: a first section and a second section joined end-to25 end to extend coaxially along a longitudinal axis, the first section being downstream of the second section; the first section comprising a first flow duct extending therethrough and offset from the longitudinal axis and having a first cross-sectional area; the second section comprising a second flow duct extending therethrough and offset from the longitudinal axis and having a cross-sectional area; wherein the first and second section 30 are moveable relative to each other to align the first and second flow ducts and form a continuous flow path extending through both sections; and wherein the cross-sectional area of the first flow duct is smaller than the cross-sectional area of the second flow duct.

Advantageously, by aligning the first and second flow ducts a flow path of low resistance through the filter is created. By restricting the cross-sectional area of the flow

- 2 path in the first flow duct the velocity of the smoke flow is increased which results in a better taste intensity and larger smoke amplitude.

The first flow duct in the first section may comprise a plurality of flow ducts, each flow duct in the first section being offset from the longitudinal axis, the first and second section being moveable relative to each other to enable a selected flow duct in the first section to be aligned with the second flow duct in the second section to define the continuous flow path extending through both sections. Preferably, the first and second sections are rotatable relative to each other to enable a selected flow duct in the first section to be aligned with the second flow duct.

Preferably, the cross-sectional area of each of the flow ducts in the first section is different to the cross-sectional area of each of the other flow ducts in the first section.

In some embodiments, the cross-sectional area of each of the flow ducts in the first section is less than the cross-sectional area of the second flow duct in the second section.

Preferably, each flow duct of the first flow duct in the first section is cylindrical.

In one embodiment, the flow ducts in the first section are spaced such that only one of the flow ducts in the first section can be aligned with the second flow duct in the second section at a time.

In another embodiment, the flow ducts in the first section are spaced such that more than one of the flow ducts in the first section can be aligned with the second flow duct in the second section at a time.

Preferably, the second flow duct in the second section comprises a plurality of flow ducts extending through the second section, each of the flow ducts in the second section extending parallel to but offset from the longitudinal axis, the first and second sections being moveable relative to each other to enable a selected flow duct of the second flow duct in the second section to be aligned with the first flow duct in the first section to define the continuous flow path extending through both sections.

-3The cross-sectional area of each of the flow ducts in the second section may be different to the cross-sectional area of the other flow ducts in the second section.

In one embodiment, the flow ducts in the second section are positioned such that only one of the flow ducts in the second section is alignable with the first flow duct in the first section at a time.

Each flow duct in the second section maybe cylindrical.

In one embodiment, at least one of the flow ducts in the first section reduces in crosssectional area in a downstream direction, the cross-sectional area of the first flow duct having a maximum cross-sectional area proximate to the second section.

A filtration material and/or a flavourant maybe located in the first and/or second flow 15 duct.

The filter may further comprise a third section attached to the second section such that a rod of aerosolisable material is attachable to the second section via the third section, the third section comprising a filtration material. Optionally, an aerosol flow path through the third section may be tortuous.

In one embodiment, the first flow duct in the first section comprises a plurality of flow ducts in the first section, each of the flow ducts in the first section being offset from the longitudinal axis, and wherein the second flow duct in the second section comprises a 25 plurality of flow ducts in the second section, each of the flow ducts in the second section being offset from the longitudinal axis, the first and second sections being moveable relative to each other to enable at least one selected flow duct in the first section to be aligned with at least one selected flow duct in the second section to define the continuous flow path extending through both sections.

Preferably, each of the plurality of flow ducts in the first and second sections is arcuate and extends in a circumferential direction.

At least one of the plurality of flow ducts in at least one of the first and second sections 35 may extend further in the circumferential direction than another one of the plurality of flow ducts in the same section.

-4The first section of the filter may be rotatable relative to the second section of the filter.

At least one of the first section and the second section is a filter rod section formed from filtration material.

In accordance with another aspect of the invention, there is provided a tobacco industry product comprising a filter having a first section and a second section joined end-toend to extend coaxially along a longitudinal axis, the first section being downstream of 10 the second section; the first section comprising a first flow duct extending therethrough offset from the longitudinal axis and having a first cross-sectional area; the second section comprising a second flow duct extending therethrough offset from the longitudinal axis and having a cross-sectional area; wherein the first and second section are moveable relative to each other to align the first and second flow ducts and form a 15 continuous flow path extending through both sections; and wherein the cross-sectional area of the first flow duct is smaller than the cross-sectional area of the second flow duct, and a rod of aerosolisable material attached proximate to the second section.

In one emboidment, the rod of aerosolisable material is attached to the second section. 20 In another embodiment, the filter further comprises a third section located between the second section and the rod of aerosolisable material, and the rod of aerosolisable material is attached to the third section.

Preferably, the second section is fixed relative to the rod of aerosolisable material and 25 the first section is rotatable relative to the second section and to the rod of aerosolisable material.

Brief Description of the Drawings

So that the invention may be more fully understood, embodiments thereof will now be 30 described by way of example only, with reference to the accompanying drawings in which:

Fig. 1 shows a schematic perspective view of a smoking article comprising a filter according to an embodiment of the present invention;

-5Fig. 2 shows a schematic perspective view of a filter according to a first embodiment of the present invention in which flow ducts in a first and second filter rod sections are not aligned;

Fig. 3 shows a schematic perspective view of the filter in Fig. 3 in which a first flow duct 5 of the first flow duct is aligned with a second flow duct of the second flow duct;

Fig. 4 shows a schematic perspective view of a filter according to a second embodiment of the present invention in which flow ducts in the first and second filter rod sections are not aligned;

Fig. 5 shows a schematic perspective view of the filter in Fig. 4 in which a first flow duct 10 of the first flow duct in the first filter rod section is with a third flow duct of the second flow duct in the second filter rod section;

Fig. 6 shows a schematic perspective view of the filter in Fig. 4 in which the first flow duct of the first flow duct in the first filter rod section partially overlaps a second and third flow duct of the second flow duct in the second filter rod section and a second flow 15 duct of the first flow duct in the first filter rod section is aligned with the third flow duct of the second flow duct in the second filter rod section;

Fig. 7 shows a schematic perspective view of a filter according to a third embodiment of the present invention;

Fig. 8 shows a schematic perspective view of a filter according to a fourth embodiment 20 of the present invention in which a first and second duct of a first flow duct in a first filter rod section are aligned with a second duct in a second filter rod section;

Fig. 9 shows a schematic perspective view of a filter according to a fifth embodiment of the present invention;

Fig. 10 shows a schematic perspective view of a filter according to a sixth embodiment 25 of the present invention; and

Fig. 11 shows a schematic cross-sectional side view about the longitudinal axis of symmetry of an exemplary embodiment of a smoking article in which means for rotating the filter between its first and second orientations is shown.

Detailed Description

Reference is made herein to a ‘tobacco industry product’. This refers to any item made in, or sold by, the tobacco industry, typically including a) cigarettes, cigarillos, cigars, or for roll-you-own cigarettes, (whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco, or tobacco substitutes); b) non-smoking products incorporating tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco, or tobacco substitutes such as heat-not-burn products and electronic cigarettes. This list is

-6not intended to be exclusive but merely illustrates a range of products which are made and sold in the tobacco industry.

Fig. i shows an example of a tobacco industry product. In this example, the tobacco industry product is a smoking article to comprising a filter 1 according to the present invention and a rod of aerosolisable material n. A user places a mouth end 4 of the filter 1 in his mouth and may heat or burn the free end of the rod of aerosolisable material 11 if it is, for example, a tobacco rod. The user then draws aerosol through the filter 1 of the smoking article 10 by inhaling.

Figs. 2 to 11 show embodiments of a filter 1,15, 20, 25, 30, 35 for the smoking article 10, shown in Fig. 1. The filter 1,15, 20, 25, 30, 35 comprises a first section 2 and a second section 3 that are joined end-to-end. The first and second sections 2,3 extend coaxially along a longitudinal axis A of the filter 1,15, 20, 25,30,35. In the present embodiment, 15 the first section 2 has a mouth end 4 which is proximate to a consumer’s mouth during use and the second section 3 is attachable to a rod of aerosolisable material (not shown). The second section 3 may be directly or indirectly attached to the rod of aerosolisable material, as will be discussed in more detail hereinafter. Therefore, the first section 2 is downstream of the second section 3. That is, when a user draws aerosol 20 through the filter, aerosol flows through the second section 3 before it reaches the first section 2. In one embodiment, another filter section (not shown) may form the mouth end of the filter 1 instead of the first section 2.

The first section 2 comprises a first flow duct 5 extending therethrough. The first flow 25 duct 5 is formed by an aperture or duct extending through the first section 2. The first flow duct 5 is offset from the longitudinal axis A, shown by a dashed line, and has a first cross-sectional area. The axis of the first flow duct 5 extends generally parallel to the longitudinal axis A of the first section 2. The second section 3 comprises a second flow duct 6 extending therethrough. The second flow duct 6 is formed by an aperture or duct 30 through the second section 3. The second flow duct 6 is offset from the longitudinal axis

A and has a second cross-sectional area. The axis of the second flow duct 6 extends parallel to the longitudinal axis A of the second section 3. The first and second sections 2, 3 are moveable relative to each other to align the first and second flow ducts 5, 6 and form a continuous path 7 extending through both sections 2, 3 of the filter 1,15, 20, 25, 35 30, 35· The cross-sectional area of the first flow duct 5 is smaller than the crosssectional area of the second flow duct 6.

-ΊΙη the present embodiment, the first and second sections 2,3 are rotatable relative to each other about the longitudinal axis A to align the first and second flow ducts 5, 6. However, in an alternative embodiment, it is envisaged that the first and second flow ducts 5, 6 can be aligned by, for example, translational movement of the first section 2 relative to the second section 3.

Referring to Figs. 2 and 3, a first embodiment of the filter 1 according to the present invention is shown. In the first embodiment of the filter 1, the first flow duct 5 in the 10 first section 2 comprises a plurality of flow ducts 5a, 5b. Each of the plurality of flow ducts 5a, 5b are formed by an aperture extending through the first section 2 parallel to but offset from the longitudinal axis A of the filter 1. The second flow duct 6 in the second section 3 also comprises a plurality of flow ducts 6a, 6b. Each of the plurality of flow ducts 6a, 6b in the second section 3 are formed by an aperture through the second 15 section 3 parallel to but offset from the longitudinal axis of the filter 1. The first and second sections 2,3 are rotatable relative to each other to enable at least one selected flow duct 5a in the first section 2 to be aligned with at least one selected flow duct 6b in the second section 3. One of the flow ducts 5a, 5b in the first section 2 forms a first flow passage through the first section 2 when it is aligned with one of the second flow ducts 20 6a, 6b in the second section 3. One of the flow ducts 6a, 6b in the second section 3 forms the second flow passage through the second section 3 when it is aligned with one of the flow ducts 5a, 5b in the first section 2. The selected aligned flow ducts 5a, 6b define the continuous flow path 7 which extends through both sections 2,3 of the filter 1.

In the present embodiment, the plurality of flow ducts 5a, 5b, 6a, 6b are arcuate and extend in a circumferential direction. They have a cross-sectional area that is generally the form of a sector of an annulus. Furthermore, the second flow duct 5b, 6b extends further in the circumferential direction than the first flow duct 5a, 6a. In the embodiment shown in Figs. 2 and 3, the first flow duct 5a, 6a extends through approximately 35 degrees in the circumferential direction whereas the second flow duct 5b, 6b extends through approximately 110 degrees in the circumferential direction.

However, it will be understood that in an alternative embodiment the size of the plurality of flow ducts 5a, 5b, 6a, 6b may vary.

-8Fig. 2 shows the first embodiment of the filter 1 in a first position in which neither of the plurality of flow ducts 5a, 5b in the first section 2 overlap with either of the plurality of flow ducts 6a, 6b in the second section 3. In this position, the flow ducts 5a, 5b in the first section 2 have been rotated 180 degrees relative to the flow ducts 6a, 6b in the second section 3 such that there is no continuous flow path defined through the filter 1.

Referring now to Fig. 3, the first embodiment of the filter 1 is shown in a second position. In the second position, the first section 2 has been rotated relative to the second filter rod section 3. In Fig. 3 the first filter rod section 2 has been rotated approximately 60 degrees in the anticlockwise direction about the longitudinal axis A of the filter 1.

When rotating the first section 2 into the position shown in Fig. 3, the first flow duct 5a in the first section 2 begins to overlap the second flow duct 6b in the second section 3.

When the first flow duct 5a and second flow duct 6b begin to overlap, the continuous path 7 is formed through the filter 1. When the flow ducts 5a, 6b initially begin to overlap is when the orifice 8 is its smallest. The smaller the orifice 8, the more the flow is accelerated as it flows from the second section 3 to the first section 2. Acceleration of the air flow at the orifice 8 is best maintained when the cross-sectional area of the orifice 8 and the selected flow duct 5a in the first section 2 are the same. However, as mentioned above, the largest acceleration of the air flow at the orifice 8 occurs when the degree of overlap of the communicating flow ducts 5a, 6b is the smallest

The first section 2 is rotated further relative to the second section 3 until it reaches the second position shown in Fig. 3. In the second position, the continuous path 7 is defined by the second flow duct 6b in the second section 3, the first flow duct 5a in the first section 2, and the orifice 8 formed between the two where they meet. Due to the smaller cross-sectional area of the first flow duct 5a in the first section 2 than the second flow duct 6b in the second section 3, the air flow in the first flow duct 5a in the first section 2 flows quicker than the air flow in the second flow duct 6b in the second section 3. The larger the difference in the cross-sectional area of the communicating flow ducts which form the first and second flow ducts 5, 6 in the first and second sections 2,3, the quicker the air flow in the selected first flow duct 5a.

The filter 1 may further comprise a limiting projection (not shown) which is configured to limit the rotation of the first section 2 relative to the second section 3. The limiting

-9proj ection may be placed to prevent the first section 2 being rotated relative to the second section 3 such that both the first and second ducts 5a, 5b of the first section 2 do no overlap with the second duct 6b of the second section 3 at the same time. In such a position, the combined cross-sectional area of the downstream path through the first and second flow ducts 5a, 5b in the first section 2 is greater than the cross-sectional area of the second duct 6b in the second section 3. Therefore, the air flow would decelerate when passing from the second flow duct 6b in the second section 3 into the first and second flow ducts 5a, 5b in the first section 2 due to the conservation of mass.

Referring now to Figs. 4 to 6, there is shown a schematic perspective view of a second embodiment of a filter 15 for a smoking article 10. The filter 15 shown in Figs. 4 to 6 are generally the same as the embodiment of the filter 1 described above, except that the second embodiment comprises three flow ducts instead of two, and so a detailed description will be omitted herein. Furthermore, features and components of the filter

15 that are the same as features and components of the filter 1 will retain the same terminology and reference numerals.

In the second embodiment of the filter 15, a first flow duct 5 in a first section 2 comprises a plurality of flow ducts 5a, 5b, 5c which each extend parallel to but offset 20 from the longitudinal axis A of the filter 15. A second flow duct 6 in a second section 3 also comprises a plurality of flow ducts 6a, 6b, 6c which each extend parallel to but offset from the longitudinal axis A of the filter 15. The first and second sections 2, 3 are rotatable relative to each other to enable at least one selected flow duct 5a in the first section 2 to be aligned with at least one selected flow duct 6c in the second section 3, as 25 shown in Fig. 5. The selected aligned flow ducts 5a, 6c define a continuous flow path 7 which extends through both sections 2, 3.

In the present embodiment, the plurality of flow ducts 5a, 5b, 5c, 6a, 6b, 6c are arcuate and extend in a circumferential direction. They have a cross-sectional area that is generally the form of a sector of an annulus. Furthermore, the third flow duct 5c, 6c extends further in the circumferential direction than the first and second flow ducts 5a, 5b, 6a, 6b. In the embodiment shown in Figs. 4 to 6, the first and second flow ducts 5a, 5b, 6a, 6b extend through approximately 35 degrees in the circumferential direction whereas the third flow duct 5c, 6c extends through approximately 65 degrees in the circumferential direction. However, it will be understood that in an alternative embodiment the size of the plurality of flow ducts may vary. For example, the first flow

- 10 duct 5a, 6a may extend through approximately 25 degrees and the second flow duct 5b, 6b may extend through approximately 35 degrees. In such an embodiment it is preferable that the flow ducts are positioned in order of increasing or decreasing angle size through which they extend in the circumferential direction.

Fig. 4 shows the second embodiment of the filter 15 in a first position in which the plurality of flow ducts 5a, 5b, 5c in the first section 2 do not overlap with the plurality of flow ducts 6a, 6b, 6c in the second section 3. In this position, the flow ducts 5a, 5b, 5c in the first section 2 have been rotated 180 degrees relative to the flow ducts 6a, 6b, 6c in 10 the second section 3 such that there is no continuous flow path defined through the filter 15.

Referring to Fig. 5 now, the second embodiment of the filter 15 is shown in a second position in which the first section 2 has been rotated relative to the second section 3. In 15 Fig. 5 the first section 2 has been rotated approximately 50 degrees in the anticlockwise direction about the longitudinal axis A of the filter 15.

The effect of rotating the first section 2 into the position shown in Fig. 5 so that the first flow duct 5a of the first section 2 begins to overlap the third flow duct 6c in the second 20 section 3 to form a continuous path 7 through the filter 1 is generally the same as described above in relation to Fig. 3. That is, due to the smaller cross-sectional area of the first flow duct 5a in the first section 2 than the third flow duct 6c in the second section 3, the air flow in the first flow duct 5a is quicker than the air flow in the third flow duct 6c.

Referring to Fig. 6 now, the second embodiment of the filter 15 is shown in a third position in which the first section 2 has been rotated relative to the second section 3 by approximately too degrees in the anticlockwise direction about the longitudinal axis A of the filter 15 from the first position.

When rotating the first section 2 into the position shown in Fig. 6, the first flow duct 5a of the first section 3 begins to overlap the second flow duct 6b of the second section 3 to form a continuous path 7 through the filter 15. The second flow duct 5b of the first section 2 also begins to overlap the third flow duct 6c of the second section 3 to form a 35 continuous flow path 7 through the filter 15. Therefore, in this orientation, the first flow passage is formed by the first and second flow ducts 5a, 5b of the first section 2 and the

- 11 second flow passage is formed by the second and third flow ducts 6b, 6c of the second section 3.

The first section 2 is rotated further relative to the second section 3 until it reaches the third position shown in Fig. 6. In the third position, the continuous path 7 is defined by the second and third flow ducts 6b, 6c in the second section 3, the first and second flow ducts 5a, 5b in the first section 2, and an orifice 8 formed between the flow ducts where they meet. Due to the smaller combined cross-sectional areas of the first and second flow ducts 5a, 5b in the first section 2 than the second and third flow ducts 6b, 6c in the 10 second section 3, the air flow through the path in the first section 2 is quicker than the air flow through the path in the second section 3.

The air flow along the portion of the continuous path 7 in the first section 2 formed when the filter 15 is in its third position is slower than when the filter 15 is in its second 15 position because the decrease in the cross-sectional area of the continuous path 7 is smaller than in the second position.

The filter 15 may further comprise a limiting projection (not shown) which is configured to limit the rotation of the first section 2 relative to the second section 3 so 20 that the third flow duct 5c of the first section 2 does not overlap with the third flow duct 6c of the second section 3. In such a position, the combined cross-sectional area of the downstream path through the first section 2 would be greater than the cross-sectional area of the path through the second section 3 which would result in the air flow decelerating when passing from the flow ducts in the second section 3 to the flow ducts 25 in the first section 2.

Referring now to Fig. 7, a schematic perspective view of a third embodiment of a filter 20 for a smoking article 10 according to the present invention is shown. The filter 20 shown in Fig. 7 is generally the same as the embodiment of the filter 1 described above, 30 except that the third embodiment comprises cylindrical ducts instead of arcuate ducts, and so a detailed description will be omitted herein. Furthermore, features and components of the filter 20 that are the same as features and components of the filter 1 will retain the same terminology and reference numerals.

In the third embodiment, the first and second sections 2, 3 each comprise a plurality of flow ducts 5a, 5b, 6a, 6b. The flow ducts 5a, 5b, 6a, 6b are cylindrical and extend

- 12 through the sections 2,3. The first flow ducts 5a, 6a have a smaller cross-sectional area than the second flow ducts 5b, 6b. The flow ducts 5a, 5b, 6a, 6b are offset from the longitudinal axis A of the filter 20.

In the position shown in Fig. 7, the first section 2 has been rotated by 180 degrees relative to the second section 3. Thus, the continuous path 7 through the second flow duct 6b in the second section 2 and the first flow duct 5a in the first section 2 experiences an acceleration as it passes through the orifice 8 between the two.

Referring now to Fig. 8, there is shown a fourth embodiment of a filter 25 for a smoking article 10, shown in Fig. 1. Features and components of the filter 25 that are the same as features and components of the filter 1 will retain the same terminology and reference numerals.

In the fourth embodiment of the filter 25, a first section 2 has a first flow duct 5 comprising a plurality of flow ducts. In the embodiment illustrated in Fig. 8, the first flow duct 5 comprises four flow ducts 5a, 5b, 5c, 5d, each of which is offset from the longitudinal axis A. Each of the four flow ducts 5a, 5b, 5c, 5d in the first section 2 has a cross-sectional shape that is a sector of an annulus. In the embodiment shown, each of the four flow ducts 5a, 5b, 5c, 5d in the first section 2 have the same cross-sectional shape and area.

However, it will be understood that in an alternative embodiment, the shape of the cross-sectional area of the plurality of flow ducts 5a, 5b, 5c, 5d may differ, for example, but not limited to, triangular, circular, or rectangular. In addition, the size of the crosssectional area of each of the plurality of flow ducts 5a, 5b, 5c, 5d in the first section 2 may differ. In such an embodiment it is preferable that the ducts are positioned in order of increasing or decreasing angle size through which they extend in the circumferential direction.

The first and second sections 2, 3 of the filter 25 are rotatable relative to each other to enable at least one of the plurality of flow ducts 5a, 5b, 5c, 5d in the first section 2 to be aligned with a second flow duct 6 in the second section 3 such that they define a continuous flow path 7 extending through the filter 25. The second flow duct 6 also has a cross-section that is the shape of a sector of an annulus but the second flow duct 6 extends through a greater angle that each of the flow ducts 5a, 5b, 5c, 5d in the first

-13section 2. In the present embodiment, the second flow duct 6 extends through 180 degrees whilst each of the flow ducts 5a, 5b, 5c, 5d in the first section 2 extend through 30 degrees.

Thus, the first section 2 can be rotated relative to the second section 3 such that the flow ducts 5a, 5b, 5c, 5d in the first section 2 overlap the second flow duct 6 sequentially. Due to the larger cross-sectional area of the second flow duct 6, it means that more of the flow ducts 5a, 5b, 5c, 5d in the first section 3 overlap the second flow duct 6 at the same time as the first section 2 is rotated further.

In the embodiment illustrated in Fig. 8, the first section 2 is rotated in the clockwise direction in order to expose subsequent flow ducts 5a, 5b, 5c, 5d to the second flow duct 6. As shown in Fig. 8, the first section 2 has been rotated 90 degrees relative to the second section 3 such that two of the flow ducts 5a, 5b already overlap the second flow duct 6. In one embodiment, the first section 2 may be rotatable in either direction through at least 360 degrees relative to the second section 3.

When only the first flow duct 5a in the first section 2 overlaps the second flow duct 6 in the second section 3, the largest change in cross-sectional area of the continuous flow 20 path 7 occurs. This results in the largest velocity of air flow through the first section 2 of the filter 25 and therefore, the largest taste intensity and aerosol amplitude is achieved.

As more flow ducts 5b, 5c, 5d in the first section 2 overlap the second flow duct 6, the change in cross-sectional area of the continuous flow path 7 is reduced such that the air flow is not accelerated to such an extent as when only one flow duct 5a overlaps the second flow duct 6.

Referring now to Fig. 9, there is shown fifth embodiment of a filter 30 according to the present invention. Features and components of the filter 30 that are the same as features and components of the filter 1 described in the first embodiment will retain the 30 same terminology and reference numerals.

In the fifth embodiment, a first section 2 comprises a first flow duct 5 having a plurality of flow ducts 5a, 5b, 5c extending therethrough. Each of the plurality of flow ducts 5a, 5b, 5c extend parallel to but are offset from the longitudinal axis A of the filter 30.

Furthermore, a second section 3 upstream of the first section 2 comprises a second flow duct 6. The first and second sections 2, 3 are rotatable relative to each other to enable a

-14selected flow duct 5a, 5b, 5c to be aligned with the second flow duct 6 to define a continuous flow path 7 extending through both sections 2, 3 of the filter 30.

The cross-sectional area of each of the three flow ducts 5a, 5b, 5c in the first section 2 is 5 different. That is, each one of the flow ducts 5a, 5b, 5c have a different cross-section to one another and a cross-section that is smaller than the cross-sectional area of the second duct 6. In the present embodiment, each of the flow ducts 5a, 5b, 5c and the second duct 6 have a circular cross-section and so form a cylindrical path through the sections 2,3, although it will be understood that in alternative embodiments the cross10 sections of the first and second ducts 5, 6 may be different.

In the present embodiment, the plurality of flow ducts 5a, 5b, 5c are spaced such that a single flow duct 5a can overlap the second duct 6 at a time to accelerate the air flow through the filter 30. In addition, the plurality of flow ducts 5a, 5b, 5c are spaced such 15 that more than one of the plurality of flow ducts 5a, 5b, 5c can be partially aligned with the second flow duct 6 at a time. However, the flow ducts 5a, 5b, 5c are also dimensioned such that when two of the flow ducts 5a, 5b overlap the second duct 6, their combined cross-sectional area is smaller than the cross-sectional area of the second duct 6. Therefore, the flow in the first section 2 still experiences a reduction in 20 area and thus an increase in velocity. However, in another embodiment, the plurality of flow ducts 5a, 5b, 5c in the first section 2 maybe spaced so that they can only communicate with the second duct 6 one at a time.

In the embodiment shown in Fig. 9, the first duct 5a in the first section 2 has a larger cross-section than the second flow duct 5b, which in turn has a larger cross-section than the third flow duct 5c. Therefore, air flow through the continuous flow path 7 when only the third flow duct 5c communicates with the second duct 6 is the fastest.

Referring now to Fig. 9, there is shown a sixth embodiment of a filter 35 according to 30 the present invention. Features and components of the filter 35 that are the same as features and components of the filter 1 described in the first embodiment will retain the same terminology and reference numerals

In the sixth embodiment, a second section 3 comprises a second flow duct 6 having a 35 plurality of flow ducts 6a, 6b, 6c extending therethrough. Each of the plurality of flow ducts 6a, 6b, 6c extending parallel to but are offset from the longitudinal axis A. A first

-ι₅section 2 is located downstream of the second section 3. The first and second sections 2, 3 are rotatable relative to each other to enable a selected flow duct 6a, 6b, 6c of the second section 3 to be aligned with the first flow duct 5 to define the continuous flow path 7 extending through both sections 2,3 of the filter 35.

The cross-sectional area of each of the three flow ducts 6a, 6b, 6c in the second section is different. That is, each one of the flow ducts 6a, 6b, 6c have a different cross-section to one another and a cross-section that is larger than the cross-sectional area of the first duct 5. In the present embodiment, the flow ducts 6a, 6b, 6c and first flow duct 5 have a circular cross-section to form a cylindrical path through the sections 2, 3. The plurality of flow ducts 6a, 6b, 6c of the second section 3 6 are positioned such that only one of the flow ducts 6a, 6b, 6c aligns with the first flow duct 5 at a time.

In the embodiment shown in Fig. 10, the first flow duct 6a in the second section 3 has a larger cross-section than the second flow duct 6b, which in turn has a larger crosssection than the third flow duct 6c. Therefore, air flow through the continuous flow path 7 when the first flow duct 6a communicates with the first flow duct 5 is the fastest.

In one embodiment, at least one of the flow ducts 5a of the first section 2 may reduce in cross-sectional area in a downstream direction towards the mouth end 4 of the filter 1, 15, 20, 25. Preferably, the at least on flow duct tapers as this is more aerodynamically efficient than a step change. In such an embodiment the cross-sectional area of the first flow duct 5 referred to above is the maximum cross-sectional area of the flow duct 5a of the first section 2, the first flow duct 5 tapering away from the maximum cross25 sectional area downstream towards the mouth end 4. The advantage of the first flow duct 5 tapering downstream towards the mouth end 4 of the filter 1,15, 20, 25 is an increased restriction in the cross-sectional area of the continuous flow path 7 which results in a further increased flow velocity at the mouth end 4. It will be understood that the taper may be replaced by a step change reduction in the cross-sectional area of the first flow duct 5a in the first section 2.

In yet another embodiment, a filtration material and/or a flavourant (not shown) may be located in at least one of the first and second flow ducts 5, 6. The filtration material and/or flavourant may extend the length of one of the flow ducts 5, 6 or may only occupy a section of its length. In other embodiment, at least one of the first section 2 and second section 3 may be a filer rod section that is formed by a filtration material. In

-16such embodiments, the filtration material may be impregnated with flavourant or the walls of the ducts may be coated with flavourant. Alternatively, the filter i, 15, 20, 25, 30, 35 may further comprise a third section (not shown) attached to the second section 3 such that the rod of aerosolisable material 11 is attachable to the third section, the third section comprising a filtration material with no flow passages formed by an aperture extending therethrough. The aerosol flow must instead flow through a tortuous aerosol flow path through the filtration material that forms the third section. In some embodiments, the third section may comprise a flavourant.

The filter 1,15, 20, 25,30, 35 may be formed from, for example, but not limited to, cellulose acetate, a plastic material, or steam-set cellulose acetate. In an embodiment in which the filter 1,15, 20, 25 is formed from a plastic material, the air flow through the filter 1,15, 20, 25, 30, 35 is only through the first and second flow ducts 5, 6. In an embodiment in which the filter 1,15, 20,25,30,35 is formed by cellulose acetate, there will always be a flow path for air to be drawn through but a continuous path 7 formed by the first and second flow ducts 5, 6 overlapping will only be created by the user rotating the first and second sections 2,3 relative to one another.

An example showing how the first and second section 2, 3 of the filter 1,15, 20, 25, 30,

35 may be rotatably fixed together is shown in Fig. 11. Specifically, Fig. 11 shows a filter

1,15, 20, 25, 30, 35 split in half along its longitudinal axis.

The smoking article 10 further comprises an inner wrap 41, in the form of a sleeve. The inner wrap 41 is a cylindrical tube, extending around the circumference of the rod of aerosolisable material 11, and the first and second sections 2,3. The inner wrap 61 is formed from a first blank of sheet material. The rod of aerosolisable material 11 and the second filter rod section 3 are dimensioned to rotate as a unit around the longitudinal axis A within the inner wrap 41.

The inner wrap 41 may be formed with a separation line 42 which extends substantially circumferentially. The separation line 42 is a frangible connection, for example, in the form of perforation line. The material of the inner wrap 41 is configured to easily break along the separation line 42 into a forward part 41a and a rearward part 41b to allow relative rotation of the first and second sections 2,3. Once the separation line 42 is broken, a first interface 43 is formed between the forward and rearward parts 41a, 41b of the inner wrap 41.

-17The smoking article 10 further comprises an outer wrap 45. The outer wrap 45 extends around the circumference of the inner wrap 41. The outer wrap 45 is in the form of a cylindrical tube. The outer wrap 45 is formed from a second blank of sheet material.

The material forming the outer wrap 45 may also include a separation line 46, which extends substantially circumferentially. The separation line is a frangible connection, which is configured to break along the separation line 46 into a forward part 45a and a rearward part 45b. The forward part 45a is affixed to the first part of the smoking 10 article 10. Once the separation line 46 is broken, a second interface 47 is formed between the forward part 45a and the rearward part 45b.

The forward part 41a of the inner wrap 41 may be affixed to the first section 2 of the filter 1,15, 20, 25,30,35 by a first connection area 50. The rearward part 41b of the 15 inner wrap 41 may be affixed to the second section 3 of the filter 1,15, 20, 25, 30, 35 and/or the rod of aerosolisable material 11 by a second connection area 51. The forward part 45a of the outer wrap 45 may be affixed to the forward part 41a of the inner wrap 41 by a third connection area 52. The rearward part 45b of the outer wrap 45 may be connected to the rearward part 41b of the inner wrap 41 by a fourth connection area 53.

The first, second, third, and fourth connection areas 50, 51, 52, 53 may comprise adhesive to adhere the adjacent layers together.

The smoking article 10 may further comprise a first element 55 on the outer surface of the inner wrap towards the rear of the forward part 41a of the inner wrap 41. The first 25 element 55 extends circumferentially around the outer surface of the inner wrap 41.

The smoking article 10 may further comprise a second element 56 on the inner surface of the outer wrap 45 towards the front of the rearward part 45b of the outer wrap 55.

The second element 56 extends circumferentially around the inner surface of the outer wrap 45. The first element 55 is located rearward of the second element 56. The first 30 and second elements 55,56 are configured to engage to prevent the first and second sections 2, 3 of the filter 1,15, 20, 25, 30, 35 from separating whilst still allowing them to rotate relative to one another.

In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration various embodiments in which the claimed invention(s) maybe practiced and provide for a superior filter. The advantages and features of the

-18disclosure are of a representative sample of embodiments only, and are not exhaustive and/or inclusive. They are presented only to assist in understanding and teach the claimed features. It is to be understood that advantages, embodiments, examples, functions, features, structures and/or other aspects of the disclosure are not to be 5 considered limitations on the disclosure as defined by the claims or limitation on equivalents to the claims, and that other embodiments may be utilised and modifications maybe made without departing from the scope and/or spirit of the disclosure. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, 10 parts, steps, means, etc. In addition, the disclosure includes other inventions not presently claimed, but which may be claimed in the future.

Claims

1. A filter for a tobacco industry product comprising:

a first section and a second section joined end-to-end to extend coaxially along a 5 longitudinal axis, the first section being downstream of the second section;

the first section comprising a first flow duct extending therethrough and offset from the longitudinal axis and having a first cross-sectional area;

the second section comprising a second flow duct extending therethrough and offset from the longitudinal axis and having a second cross-sectional area;

io wherein the first and second sections are moveable relative to each other to align the first and second flow ducts and form a continuous flow path extending through both sections; and wherein the cross-sectional area of the first flow passage is smaller than the cross-sectional area of the second flow passage.

2. The filter according to claim 1, wherein the first flow duct in the first section comprises a plurality of flow ducts extending through the first section, each flow duct in the first section being offset from the longitudinal axis, the first and second sections being moveable relative to each other to enable a selected flow duct in the first section

20 to be aligned with the second flow duct in the second section to define the continuous flow path extending through both sections.

3. The filter according to claim 2, wherein the cross-sectional area of each of the flow ducts in the first section is different to the cross-sectional area of each of the other

25 flow ducts in the first section.

4. The filter according to claim 3, wherein the cross-sectional area of each of the flow ducts in the first section is less than the cross-sectional area of the second flow duct in the second section.

5. The filter according to any one of claims 2 to 4, wherein each flow duct in the first section is cylindrical.

6. The filter according to any one of claims 2 to 5, wherein the flow ducts in the

35 first section are spaced such that only one of the flow ducts in the first section can be aligned with the second flow duct in the second section at a time.

- 20

7- The filter according to any one of claims 2 to 5, wherein the flow ducts in the first section are spaced such that more than one of the flow ducts in the first section can be aligned with the second flow duct in the second section at a time.

8. The filter according to any one of the preceding claims, wherein the second flow duct in the second section comprises a plurality of flow ducts extending through the second section, each of the flow ducts in the second section extending parallel to but offset from the longitudinal axis, the first and second sections being moveable relative

10 to each other to enable a selected flow duct in the second section to be aligned with the first flow duct in the first section to define the continuous flow path extending through both sections.

9. The filter according to claim 8, wherein the cross-sectional area of each of the

15 flow ducts in the second section is different to the cross-sectional area of the other flow ducts in the second section.

10. The filter according to claim 8 or claim 9, wherein the flow ducts in the second section are positioned such that only one of the flow ducts in the second section is

20 alignable with the first flow duct in the first section at a time.

11. The filter according to any one of claims 8 to 10, wherein each flow duct in the second section is cylindrical.

25

12. The filter according to any preceding claim, wherein at least one of the flow ducts in the first section reduces in cross-sectional area in a downstream direction, the cross-sectional area of the at least one flow duct in the first section having a maximum cross-sectional area proximate to the second section.

30

13. The filter according to any one of the preceding claims, further comprising a filtration material and/or a flavourant located in the first and/or second flow duct.

14. The filter according to any one of the preceding claims, further comprising a third section attached to the second section such that a rod of aerosolisable material is 35 attachable to the second section via the third section, the third section comprising a

- 21 filter rod formed from a filtration material, and optionally wherein an aerosol flow path through the third section is tortuous.

15. The filter according to any one of the preceding claims, wherein the first flow

5 duct in the first section comprises a plurality of flow ducts in the first section, each of the flow ducts in the first section being offset from the longitudinal axis, and wherein the second flow duct in the second section comprises a plurality of flow ducts in the second section, each of the flow ducts in the second section being offset from the longitudinal axis, the first and second sections being moveable relative to each other to 10 enable at least one selected flow duct in the first section to be aligned with at least one selected flow duct in the second section to define the continuous flow path extending through both sections .

16. The filter according to claim 15, wherein each of the plurality of flow ducts in the 15 first and second sections is arcuate and extends in a circumferential direction.

17. The filter according to claim 16, wherein at least one of the plurality of flow ducts in at least one of the first and second sections extends further in the circumferential direction than another one of the plurality of flow ducts in the same

20 section.

18. The filter according to any one of the preceding claims, wherein the first section is rotatable relative to the second section.

25

19. The filter according to any one of the preceding claims, wherein at least one of the first section and the second section is a filter rod section formed from filtration material.

20. A tobacco industry product comprising a filter according to any one of the

30 preceding claims and a rod of aerosolisable material attached proximate to the second section.

21. The tobacco industry product according to claim 20, wherein the rod of aerosolisable material is attached to the second section.

22. The tobacco industry product according to claim 20, wherein the filter further comprises a third section located between the second section and the rod of aerosolisable material, the rod of aerosolisable material being attached to the third section.

23. The tobacco industry product according to any one of claim 20 to claim 22, wherein the second section is fixed relative to the rod of aerosolisable material, and the first section is rotatable relative to the second section and relative to the rod of aerosolisable material.