WO2013060607A1

WO2013060607A1 - A device for delivering a gaseous flow to the mouth of a user

Info

Publication number: WO2013060607A1
Application number: PCT/EP2012/070556
Authority: WO
Inventors: Nicole Hooper; Nelson ONG; Domenico VENTURA
Original assignee: British American Tobacco (Investments) Limited
Priority date: 2011-10-28
Filing date: 2012-10-17
Publication date: 2013-05-02
Also published as: GB201118639D0; AR088561A1

Abstract

A device for delivering gaseous material to the mouth of a user, comprising a body with a buccal end (8) from which the user can draw a flow of the gaseous material from within the article, and an accelerator (10) to accelerate the flow of gaseous material into a coUimated gaseous jet (19) when drawn from the buccal end by the user such as to impact the rear of their buccal cavity.

Description

A device for delivering a gaseous flow to the mouth of a user

Field

This invention relates to a device for delivering gaseous material such as an aerosol to the mouth of a user, for example a smoking article such as a cigarette or a filter for a cigarette.

Background

It is well known that smoking articles such as cigarettes, cigars and cigarillos whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-burn (HNB) and aerosol generators, deliver a gaseous flow in the form of an aerosol to the mouth of a user. For smoking articles that include tobacco or like combustible products, the aerosol can include smoke generated by combustion of the combustible products. For smoking articles that comprise HNB products the areosol contains vapours generated by heating aromatic material such as tobacco. For smoking articles that comprise aerosol generators, the aerosol may contain a suspension of droplets of a substance such as nicotine.

The flow of aerosol may be delivered through a filter for example made of cellulosic tow or other filter material and the flow may also contain ventilation air, for example admitted through ventilation holes in the filter. The filter may be attached to the generator of the aerosol. The user draws on the smoking article at its buccal end so as to produce a pressure differential that draws a flow of the aerosol into the mouth and buccal cavity of the user.

Summary

Described hereinafter is a device for delivering gaseous material to the mouth of a user, having a buccal end from which the user can draw a flow of the gaseous material, and an accelerator to accelerate the flow of gaseous material into a collimated gaseous jet when drawn from the buccal end by the user into their buccal cavity, such as to impact the rear thereof.

Brief description of the drawings

In order that the invention may be more fully understood, embodiments thereof will now be described by way of illustrative example with reference to the accompanying drawings in which: Figure 1 is a longitudinal sectional view of a cigarette with a filter that accelerates the flow of smoke to the user;

Figure 2 is an enlarged sectional view of the filter shown in Figure l;

Figure 3 is a sectional view through an alternative embodiment of filter;

Figure 4 is a perspective view of the buccal end of the filter shown in Figure 3; Figure 5 is a longitudinal sectional view of another smoking article with a filter having a conical end;

Figure 6 is an enlarged perspective view of the filter illustrated in Figure 5; and Figure 7 is a longitudinal sectional view of another cigarette with a filter that accelerates the flow of smoke to the user.

Detailed description

Referring to Figures 1 and 2, a smoking article in the form of a cigarette 1 comprises an aerosol generator in the form of a rod of combustible material 2 which may comprise tobacco or tobacco containing material within a sheet wrapper 3, typically made of paper. A filter 4 includes a generally cylindrical plug of filter material of diameter df, which in this example comprises tow of cellulose acetate 5 held within a plug wrap 6. The filter 4 is coupled to the tobacco rod 2 by tipping paper 7 which is glued around the plug wrap 6 and a portion of the tobacco rod 2.

The filter 4 has a buccal end 8 which in use is received between the lips of the user (not shown) . The user lights the tobacco rod 2 at its distal end 9 so as to produce a gaseous flow comprising an aerosol of smoke which the user draws through the rod 2 and filter 4 by creating a pressure reduction below ambient in their buccal cavity.

The filter 4 includes an accelerator 10 to accelerate the flow of aerosol into the mouth of the user through buccal end 8. The accelerator 10 includes a generally tubular body 11 that has an internal passageway 12 for the aerosol flow that extends to the buccal end 8. The body 11 has a distal end opening 13 of relatively large area A_t and internal radius di, an intermediate section 14 and a tapered section 15 which reduces in radius towards a buccal end region 16 of relatively small area A₂ and radius d₂, which opens through buccal end 8. A substantially gas impervious layer 17 may be provided overling the buccal end 8 except in the region of opening 18 of the buccal end region 16 of the tubular member 11. The gas impervious layer 17 may comprise compressed filter tow or solid filter tow or could have a paper or glue covering to make it impervious. The layer 17 may however in some embodiments be omitted since the aerosol drawn through the filter will preferentially be drawn through the opening 18.

The buccal end region 16 thus defines a constriction in the passageway 12 which accelerates the gaseous flow from an initially relatively slow velocity Vi in the relatively large cross sectional area region 14, to a relatively high velocity V₂ in the buccal end region 16. As the user draws on buccal end, a coUimated jet 19 of the gaseous material is produced, which extends along the longitudinal axis X-X' of the smoking article 1. The jet 19 is coUimated in the sense that it does not diverge substantially along its length and as a result, the accelerated, focused jet 19 moves at velocity V₂ and impacts the rear of the buccal cavity of the user when the user draws on the buccal end. It will be appreciated that this differs from a

conventional cigarette in which the flow of smoke emanates from the filter over substantially the entire surface area of the buccal end, at lower velocity Vi and is not coUimated to impact the rear of the buccal cavity significantly.

It can be shown for a first order assumption that the flow of gas remains at constant density, the accelerated exit velocity V₂ produced by the Venturi effect is given by:

In the examples shown in Figures 1 and 2, the tubular member 11 defines a generally cylindrical chamber for the gaseous flow with a circular inlet 13 and outlet orifice 18. Thus, the equation (1) can be expressed as follows:

A suitable range of values of the various diameters d may be as follows:

d₂ = 1-5 - 3 mm The filter shown in Figures l and 2 may be of any suitable length, for example in the range 22-27mm.

In one particular example, df = 7mm; di = 4mm and d₂ = 2mm. From this example, it can be seen from equation (2) that the velocity V₂ = 4 Vi. Thus, 400% increase in velocity is achieved by the accelerative Venturi effect of the accelerator 10 provided by the tapered section 15 in the tubular member 11. The resulting relatively high velocity, collimated jet 19 of aerosol impinges upon the rear of the buccal cavity of the user, which has been found by user testing to have a distinctive perceptible sensory characteristic for the user as compared with the draw of a conventional cigarette. The amount of acceleration provided by the accelerator 10 is not however restricted to the particular example of 400% and a velocity increase of 100% or higher may provide the aforesaid distinctive perceptible sensory characteristic for the user.

The accelerator 10 may be used with particular effect in a low tar smoking article e.g. lmg or lower.

Also, no significant staining occurs at the buccal end due to the passage of smoke through the internal passageway 12 of the filter.

The filter may be manufactured by inserting sequence of tubular members 11 into a substantially continuous flow of tow 5 in a filter making machine before being wrapped with plug wrap in a manner well known per se in the manufacture of filter rods, which then can be cut into segments for use in individual cigarettes or pairs of cigarettes. The tubular members 11 may be formed in back-to-back pairs to be used in the manufacture of cigarettes in which tobacco rods are attached at opposite ends to a double length of filter rod and then cut in half, in a manner well known per se.

An alternative filter structure is illustrated in Figure 3 in which the filter material 5 is arranged in three filter plugs 5-1, 5-2, 5-3. The plugs may be made of the same or different filter materials. For example, the plug 5-2 may be made of cellulose acetate tow whereas plug 5-3 may comprise tow that includes a flavouring or absorbent for tobacco smoke, for example distributed particles of carbon. In order to produce the tapered region 15 in filter plug 5-1, the exterior of the filter 4 is crimped at the buccal end 8 so as to provide crimped regions 19 illustrated clearly in Figure 4. The plug 5-1 is initially tubular so as to provide an internal chamber with a constant internal diameter di. The formation of the crimped regions 20 reduces its diameter at the buccal end 18 to diameter d₂ thereby producing the tapered region 15 and the constriction which gives rise to the acceleration of the gaseous flow from velocity Vi to V₂ by means of the Venturi effect. Another example is illustrated in Figures 5 and 6 in which the acceleration of the gaseous flow by the Venturi effect is produced by an appropriate shaping of the exterior of the filter plug 5 at the buccal end 8. As shown in Figure 5, the filter material has a generally cylindrical main segment 5-4 and a conical region 5-5 which tapers from diameter di to d₂ at buccal end 8. The filter segments 5-4 and 5-5 may conveniently be made of a cellulosic tow such as cellulose actetate and either or both of them may include a flavourant and/or adsorbant for smoke. The plug wrap and/or the tipping paper 7 are arranged to conform around the exterior periphery of the conical filter plug 5-5 and may be formed in a series of segments as illustrated in Figure 6 which overlie one another and are located in place by gluing. Other covering may be utilised, for example a moulded plastics sheath or a shrinkable wrapper. In a typical example, the diameter df of the tobacco rod and filter plug 5-4 corresponds to the inlet diameter di of the conical portion 5-5 may be in the range of 5-8mm. The diameter d₂ of the outlet 18 may be of the order of 2-3mm. The filter in use produces an accelerated, collimated of gaseous flow jet aligned with the longitudinal axis X-X' as described with reference to Figures 1 and 2 which impacts the rear of the buccal cavity when the user draws on the buccal end 8.

A feature of the example illustrated in Figures 5 and 6 is that the conical, filter plug 5-5 may allow the smoking article 1 to be inserted past the user's teeth and so avoid teeth staining by smoke.

Another example of cigarette is shown in Figure 7 in which the acceleratory effect on the smoke is produced by a Venturi effect that occurs at a step change in the cross sectional area of the path for smoke drawn to the buccal end. Referring to Figure 7, rod 2 of combustible material comprises tobacco or tobacco containing material within sheet wrapper 3. Filter 4 includes a first segment comprising generally cylindrical plug 5-6 of filter material of diameter di, for example tow of cellulose acetate held within a plug wrap 6. The filter 4 also includes second segment comprising a tubular element 5-7 with an internal passageway 12 of diameter d₂ that is coupled to the first segment 5-6 by a filter wrapper 21. The filter 4 is connected to the tobacco rod 2 by tipping paper 7 which is glued around the filter wrapper 21 and a portion of the tobacco rod 2. The tubular segment 5-7 may for example be produced using the SAF (Shaped Acetate Filter) technology of Filtrona pic of Milton Keynes, GB.

The step change in diameter of the passageway 12 from di to d₂ at the junction between the filter segments 5-6 and 5-7 acts as accelerator 10 and accelerates the smoke aerosol that travels at velocity Vi through the segment 5-7 to velocity V2 in the segment 5-7 as the user draws on the buccal end 8, as as to produce a collimated jet 19 of smoke aerosol in the manner previously described with reference to Figures 1 and 2.

An example of the accleratory characteristics of the device where di = 5 mm and d₂ = 2 mm can be considered when used under the conditions of the ISO standard test for which the flow of smoke is 35cm³/sec. It can be shown that with these dimensions the velocity of smoke entering the passageway of diameter di = 5 mm is Vi = i.78m/sec, and from equation (2) is can be shown that V2=ii.i4m/sec, which corresponds to approximately 625% increase in velocity. For all of the described examples the accelerator 10 has a circular outlet orifice 18 but other shapes can be used such as elliptical or rectangular, in particular square, and generally, emodiments of the device may advantageously include a

constriction for the aerosol flow with a cross sectional area of the order of 1.8 - 9 mm² for contributing to the provision of the collimated jet of aerosol.

Ventilation holes or other means of allowing ventilation air to enter the filter may be provided in any of the examples of the devices described herein, and for example laser cut ventilation may be provided towards the distal end of the filters 4- In the foregoing examples, each smoking article comprises a cigarette with a combustible rod of tobacco 2 that acts as a smoke generator to produce an aerosol that comprises the gaseous flow that is filtered by the filter 4. However, it will be appreciated that the acceleratory principles described herein may also be used in other smoking articles, for example HNB devices in which tobacco is heated but not burned in order to produce an aerosol comprising vapours which can be used as the gaseous flow that is drawn through the filter. Similarly, the gaseous flow may be generated by means of an aerosol generator which may produce for example an aerosol of droplets containing nicotine. The filter material may be omitted for example in the case of an aerosol droplet generator. Furthermore, it will be appreciated in certain circumstances, the filter arrangement shown in the examples of Figures 1-6 may be provided as a separate unit, for example to be fitted to the aerosol generator. Also, whilst in the described examples the collimated jet 19 is disposed aligned with the longitudinal axis X-X' of the device, it could be configured to emanate from the buccal end opening 18 inclined to the axis at an angle of for example 5 -

10°. 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) may be practiced and provide for superior devices for delivering gaseous material to the mouth of a user. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. 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 considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilized and modifications may be 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, parts, steps, means, etc. In addition, the disclosure includes other inventions not presently claimed, but which may be claimed in future.

Claims

1. A device for delivering gaseous material to the mouth of a user, having a buccal end from which the user can draw a flow of the gaseous material, and an accelerator to accelerate the flow of gaseous material into a coUimated gaseous jet when drawn from the buccal end by the user into their buccal cavity, such as to impact the rear thereof.

2. A device according to claim l including an elongate body that extends to the buccal end, the body having a longitudinal axis, and the jet produced by the accelerator in use extends in the direction of the longitudinal axis of the body.

3. A device according to claim 2 wherein the body has an internal path for the gaseous flow that extends to the buccal end and the accelerator comprises a constriction in the path to accelerate the gaseous flow by means of the Venturi effect.

4. A device according to claim 3 wherein constriction comprises a tapered region of the internal passageway with a cross sectional area that decreases towards the buccal end.

5. A device according to claim 3 including an inlet for the gaseous flow and an outlet orifice through which the gaseous flow leaves the buccal end, the outlet orifice having a smaller cross sectional area than that of the inlet.

6. A device according to any preceding claim comprising a filter for filtering the gaseous material.

7. A device according to claim 6 wherein the filter comprises a generally cylindrical body of filter material.

8. A device according to claim 6 or 7 including a chamber within the filter to receive the gaseous material when filtered, and an outlet at the buccal end from which the filtered gaseous flow from the chamber emanates when drawn in the jet from the device.

9. A device according to claim 8 wherein the chamber comprises a tubular insert received within the filter material.

10. A device according to claim 6 or 7 wherein the accelerator comprises a portion of the body of filter material that tapers towards the buccal end such as to accelerate the flow of gaseous material into said collimated jet when drawn from the buccal end by the user.

11. A device according to any preceding claim including an aerosol generator to provide at least part of the gaseous material.

12. A device according to any preceding claim wherein the accelerator is configured to increase the velocity of the gaseous flow drawn from the buccal end by at least 100%.

13. A device according to any preceding claim wherein the accelerator includes a constriction for the gaseous flow with a cross sectional area of the order of 1.8 - 9 mm².

14. A filter cigarette comprising a device according to any preceding claim.

15. A smoking article for delivering an aerosol to the mouth of a user, comprising an aerosol generator for generating an aerosol, a body with a buccal end from which the user can draw a flow of the aerosol from the aerosol generator, and an accelerator to accelerate the flow of aerosol into a collimated jet when drawn from the buccal end by the user into their buccal cavity, such as to impact the rear thereof.

16. A smoking article according to claim 14 or 15 including a filter having a first segment of relatively large diameter and a second segment with an internal passageway of relatively small diameter to provide a constriction that is

configured to act as the accelerator.

17. A device for delivering an aerosol to the mouth of a user, comprising a body having a buccal end, an opening at the buccal end, a passageway in the body extending to the opening to deliver an aerosol thereto, and an accelerator comprising a restriction in the passageway to accelerate the flow of aerosol into a coUimated gaseous jet when drawn from the buccal end by the user into their buccal cavity, such as to impact the rear thereof. i8. A method of making a smoking article including:

providing a rod of smokeable material, and attaching a filter to the rod, the filter comprsing a device as claimed in any one of claims l to 13.