GB1602962A - Smoke filter - Google Patents

Description

(54) SMOKE FILTER (71) I, JAN VAN TILBURG, a Dutch subject of 74 Lyceumstraat, Alkmaar, Holland, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- My invention concerns tobacco smoke filters, most importantly for cigarettes, and in particular ventilated tobacco smoke filters in which, during smoking, external air is drawn laterally through the peripheral wall of the filter to dilute smoke passing through the filter.

According to the invention, there is provided a tobacco smoke filter comprising a body of tobacco smoke filtering material, a wrapping forming a tubular wall around the body, at least one cavity defined and substantially wholly enclosed by the body and the wrapping and extending to the tubular wall, and air-permeable means in the wrapping allowing direct passage of external ventilating air into the cavity or cavities through the wrapping, the filter body constraining the smoke flow in the cavity or cavities to concentrate adjacent said tubular wall, and the air-permeable means being disposed at the region of concentrated smoke flow whereby at least a major portion of tobacco smoke and the ventilating air entering the cavity or cavities form a mixture over a region of the filter extending inwardly of its peripheral region.

I have found that in prior proposed ventilated tobacco smoke filters, including those which have been available commercially, the ventilating air after passing into the filter is substantially restricted, in its passage through the filter to the mouth end during smoking, to a narrow peripheral flow path through the filter; the ventilating air is thus used inefficiently, mixing substantially only with the smoke in the peripheral filter region, with the smoke passing centrally of the filter being substantially unaffected. The full benefits of air ventilation have thus not been realised.I believe it to be for this reason that in prior ventilated filters the degree of air dilution obtainable is severely limited if a smoke acceptable to the smoker is to be provided; thus prior ventilated filters are limited to a degree of air dilution on the order of about 20% or 30%; cigarettes with such filters having higher air dilution, e.g.

50% or 80%, are tasteless and unsmokeable, smoking like a "leaking" cigarette.

Use of filters of my invention permits maintenance of a smooth smoke of acceptable taste with air dilutions of up to 80% and greater, resulting in a filtered smoke of low tar content but low tar/nicotine ratio, this being of especial advantage and importance.

Medical opinion indicates that it is the tar in tobacco smoke which is the health hazard, but that its content of nicotine, for which the tobacco is smoked, can with safety be quite high. My filters can also give high CO reduction and have been observed to give (compared to a cigarette of the same amount of tobacco with a conventional filter) up to 30% increase in smoking duration or conversely (compared to a conventional cigarette of the same smoking duration) up to 25% saving in tobacco.

Various embodiments of my filter are possible. In a preferred embodiment, the or each directly ventilated cavity is shaped to cause a variation, radially of the filter, of the speed of smoke flow into the cavity, thus engendering turbulence and hence extensive mixing of smoke and ventilation air in the cavity. Thus at least the upstream wall of the or each directly ventilated cavity may extend obliquely upstream or downstream from the filter periphery. the smoke at different radial positions then having different lengths of filter to traverse (and hence encountering different flow resistances) before reaching the cavity, resulting in a radial gradient of velocity of entry to the cavity.A similar but sometimes less pronounced turbulence effect can be obtained if the downstream face of the or each cavity extends up- or downstream from the filter wall, and of course both upstream and downstream faces may be so oriented. A plurality of such directly ventilated cavities may be provided, each extending only partially across the filter and spaced angularly and optionally longitudinally of one another.

The ventilating air may enter the filter non-uniformly around its periphery. Thus whereas in conventional ventilated filters perforations for admitting ventilating air are distributed uniformly in a ring around the wrapper(s) of the filter, in the instant invention the perforations (or air permeable region(s) of the wrapper(s)) for directly ventilating the cavity may be disposed nonuniformly circumferentially of the cavity.

Thus in the case of a cavity which occupies the whole filter cross-section, direct ventilating air may enter at only one localised region around the circumference, or at two or more localised regions positioned asymmetrically around the cavity. Where a cavity extends only partially around the filter circumference, it can likewise be directly ventilated asymmetrically of the cavity circumference.

The asymmetric direct ventilation also promotes turbulence and hence good mixing of the smoke and ventilation air internally of the filter periphery.

A directly ventilated cavity in my filter may be disposed and shaped, with an upstream wall extending obliquely downstream from the filter wall, to concentrate the flow of smoke into the cavity at the upstream peripheral region of the cavity, and the flow of ventilation air into the cavity is then also concentrated at this region. Thus a major portion of the smoke passing through the filter is mixed, with all or a major part of the direct ventilation air, as soon as the smoke enters the cavity; a substantially uniform mixture of air and smoke can thus be formed in the filter and drawn into the mouth of the smoker.The cavity may for example have an upstream wall which tapers downstream from around the whole periphery of the filter, all or most of the direct ventilation air being constrained to enter the cavity around the upstream peripheral extremity of the cavity; or it might be an oblique gap across the filter, all or most of the direct ventilation air being constrained to enter the cavity at the most upstream region of its periphery.

My filters can be made of the usual filtering materials, e.g. cellulose acetate filaments or fibres, usually along with a plasticiser or paper. Different filtering materials can be used for different parts (e.g. upstream and downstream of the cavity, radially inner and outer regions etc.) of the filter. When paper is used as a filtering material, it can usefully comprise a percentage (up to 100%) of SWP (synthetic wood pulp); this will also facilitate the fixation of the cavity if it is formed by heat compressing (heat embossing or heat crimping).

The filters of my invention are effective in filtering smoke from all types of natural and synthetic tobacco and tobacco substitute (e.g.

"Cytrel" (Registered Trade Mark) and "NSM") and mixtures thereof.

At least where the inner surface of the wrapper immediately surrounding the filter is exposed to the cavity, this inner surface may carry a sticky or tacky material (e.g.

non-drying or slowly-drying adhesive) to assist retention of tar and particulate matter from the smoke.

The or each directly ventilated cavity can contain a sorbent material, e.g. activated carbon or silica gel, and/or a taste modifier such as menthol. Such additives could be present adhered to the said sticky or tacky material.

The or each cavity of my filters may be readily made or provided in many different ways e.g., starting from conventional rods, by cutting, or by compression of the rod at an elevated temperature at the localities where a cavity is to be formed, or by locally heating part of the rod, or by locally heating part of the rod followed by axial stretching (a neck is then formed), or in other suitable ways. A cavity can also be provided by juxtaposing, the required distance apart, two filter elements of appropriate opposing end configurations.

As indicated above my filters can markedly reduce the tar content of tobacco smoke whilst leaving it with a satisfactorily high nicotine/tar ratio. To enhance the latter ratio I can if desired incorporate additional nicotine, as such or in the form of a nicotine salt or other convenient derivative, in the tobacco to be smoked.

The direct ventilating air will usually enter into the directly ventilated cavity or cavities of my filters through perforations in the wrapper(s) surrounding the filter, but this is not essential and any such perforations may not be completely open. The wrapper(s) may instead have regions of inherently air permeable material separated by impermeable regions, and perforations may be covered by material (e.g. paper) of greater porosity than that of the material in which the perforations are formed.

Filters of my invention will normally have the directly ventilated cavity or cavities closed both upstream and downstream by filter material, but exceptions to this are possible, e.g. in the described case when the downstream portion of filter material has one or more restricted passages therethrough to promote turbulence within the cavity.

The invention, and various of its preferred features and advantages, are illustrated and explained in the following description to be read in conjunction with the accompanying drawings, in which: Figures 1 to 5 and 7 to 10 are side sectional views of filters according to the invention incorporated in a filtered cigarette; and Figure 6 is a similar view of a ventilated filter not according to the invention.

In the drawings and following description, like reference numerals are employed to indicate like parts.

Thus in all of the figures there are shown a cigarette having a tobacco rod 1 wrapped in a paper wrapper 3 and connected to a filter 2 wrapped in a wrapper 5 by means of a tipping overwrap 4. Each filter has at least one cavity 6, which communicates with the external air by way of perforations 7 through the filter wrapper 5 and tipping overwrap 4.

It will be appreciated that, whilst a tipping overwrap 4 is shown in all of the figures, other means, e.g. ring tipping, can be used to join rod 1 to filter 2. The filtering material of the filters shown in the drawings generally has an upstream portion I and downstream portion II.

Referring now to Figure 1 of the accompanying drawings, the filter shown has a cavity 6 which is annular and has, through one or more small holes 7, direct access to the outside atmosphere. The effect of such a shaped cavity combined with direct air vents is advantageous; in experiments in which a cavity according to Figure 1 was cut into a standard cellulose acetate filter element, about half-way along the length of the filter element, leaving a central portion 8 of about 2 mm.. the result of smoking the filtered cigarette was that the first part of the filter (I) and the walls of the chamber 6 became heavily discoloured mainly with tar while the second part (II) became only faintly discoloured.The outside air, sucked into the chamber 6. seems to cause tar particulate matter contained in the smoke to condense and deposit in the chamber 6, at least partly due to the turbulent flow created in the chamber because of the cavity shape. Between puffs, smoke is also able to escape through the air vents. The smoke inhaled has thus passed through very slightly polluted filtering material (II). A smoker cutting a conventional filter apart after having smoked a cigarette through it will be impressed by what such a filter has retained, but might also wonder what has not been retained and has gone through. Cutting apart a filter according to the invention, like that of Figure 1, and seeing an almost clean part II, leaves no doubts about the filter's effectiveness.

Variations in the configuration and nature of cavity 6 of Figure 1 may be made, as shown for example in Figure 2. Whilst Figure 2 shows the downstream face of the cavity 6 as being perpendicular to the filter axis, the filter could be employed the other way around, with this perpendicular face constituting the upstream end of the cavity.

Furthermore, whilst the cavity 6 in Figures 1 and 2 is annular, it could in practice be replaced by one or more separate cavities spaced around the circumference of the filter with intervening walls of the material from which the filter is made. It is possible for the portion 8 shown in Figures 1 and 2 to be absent, the cavity 6 then extending fully across the cross-section of the filter, but this is not preferred.

In another modification of the type of embodiment shown in Figures 1 and 2, a pair of longitudinally spaced annular cavities 6 are provided, each with their ventilation holes 7, as shown in Figure 3; once again, each cavity 6 in this embodiment might be replaced by two or more separate cavities angularly spaced around the circumference of the filter.

In the latter type of embodiment, whether as shown in Figure 1, 2 or 3, the cavity apices shown as being directly opposed could in practice be spaced from one another longitudinally of the filter, and the apex portion of the or each cavity might extend to over halfway across the filter.

Filters of the type shown in Figure 1, 2 or 3 may be of cellulose acetate fibres or filaments; in conventional filters these would usually be more or less longitudinally aligned, but in my invention a twist in the fibre bundle, throughout the filter or for example in part I only, can be of advantage in increasing the turbulence in the cavity 6 and hence the filtering efficiency. The required turbulence may also be favoured if the portion 8 of the filters is disposed offcenter.

The illustrated filters may of course be made of other materials, and different parts may be of different materials. For example a filter may have its upstream end of paper and its downstream end of cellulose acetate.

If desired, the portion 8 of the filter can be treated to render it less pervious or impervious, e.g. by heat pressing or by the application of an adhesive or of a solvent for the filter material in question, but this is not essential and a susbstantially impervious core portion 8 may in any case result naturally from the method of formation of the cavity or cavities.

The cavity or cavities in filters of the type illustrated in Figures 1 to 3 can be made readily by any of the methods previously mentioned, e.g. by cutting or deforming a conventional filter rod or by spacing end to end preformed rod portions of appropriate end configurations. Another way of forming a cavity is by means of a simple clamp or spring ring (e.g. of plastics or metal), which is fitted around a conventional filter rod to constrict it to a generally hour glass configuration, heat being applied where appropriate to assist in the constriction.

The core portion 8 in filters of the type illustrated in Figures 1. 2 and 3 need not be centrally positioned, and it need not have a simple, e.g. cylindrical configuration; its cross section may for example beÇsquare, triangular, S-shaped, Z-shaped, Y-shaped, or cruciform, etc. Its outside may touch the inside of the wrapper 5 in places, thereby sub-dividing the cavity 6 into two or more cavities in the manner described for example in United States Patent Specification No.3.533.416 (American Filtrona Corporation).

The core portion 8 of filters such as those of Figures 1 to 3 may be of different material than the filtering material(s) I and II; it may be a small rod of plastics material (polystyrene for example), or a small body of activated carbon, attached by adhesive to the remainder of the filter.

Figures 4 and 5 show further embodiments of my filter, of the same general type as those of Figures 1 to 3. In the Figure 4 filter, the material 32 of portions I and II can be of creped paper, with the central core portion 8 being formed, for example, by squeezing this part of the filter together with the application of an adhesive. In this construction, the smoke is forced to go through the paper webs, rather than flowing only between them along their surfaces as in a conventional paper filter.

Figure 5 show another embodiment where the material 32 of portion I is likewise of creped paper, but in which the portion II is a separate element which may be of a different material 70, e.g. cellulose acetate fibre or filament.

It will be noted that in Figures 4 and 5 the vents 7 for directly ventilating the annular cavity 6 are disposed at the upstream end of the cavity in each case, this being especially beneficial in resulting in all of the direct ventilation air mixing with the majority of the smoke flow (which will be concentrated preferentially in the region of the upstream peripheral extremity of the cavity 6) as soon as the smoke enters the cavity. With the turbulence caused in cavity 6, assisted by its shape and by the disposition of the vents 7, uniform mixing of all of the direct ventilation air with substantially all of the smoke may thus be obtained to give satisfactory air dilution of the smoke issuing from the exit end of the filter over the whole of its cross section. The arrows in Figures 4 and 5 indicate generally a possible flow pattern for smoke through the filters.

Figure 6 is a longitudinal sectional view through a cigarette provided with a filter which has a directly ventilated cavity but which is not according to the invention.

Figure 7 is a similar view of a cigarette having a filter which is according to the invention and which has the same air dilution as the filter of Figure 6. A variety of filters according to Figures 6 and 7 were made and attached to cigarettes, and the cigarettes were smoked for comparison. In each case, in comparison with the Figure 7 embodiment, those according to Figure 6 gave a much inferior taste and much lower tar removal, and the Figure 6 filtered cigarettes were also very hard to draw. When cut open after smoking, the filters as shown in Figure 7 were found to be markedly discoloured in the upstream section I and around the cavity 6, and to be slightly but uniformly discoloured across the downstream end of section II. Extensive and uniform air dilution has thus been obtained, the filters exhibiting excellent filtering efficiency whilst providing a smooth and tasteful smoke.The used filters according to Figure 6 however were more discoloured over the length of the downstream section II, and this discolouration was not uniform, the outer peripheral portion of section II being much less discoloured than the remainder, indicating a restricted air flow path and hence limited extent of air dilution as indicated by the arrows in Figure 6.

It will be noted that the vents 7 into the cavity 6 in Figure 7 are disposed towards the upstream end of the cavity, this being beneficial as described above in connection with Figures 4 and 5.

Figures 8 to 10 of the accompanying drawings illustrate a particularly effective type of embodiment of my inventive filter, in which a major portion of the tobacco smoke is constrained to flow into the cavity at a localised upstream peripheral extremity of the cavity, and in which all or most of the direct ventilating air is likewise constrained to enter the cavity at this extremity of the cavity due to disposition of all or most of the vents 7 or equivalent air-permeable regions of the filter wrapper(s) at this extremity. This ensures good mixing of a major proportion of the smoke with at least a major proportion of the direct ventilation air, hence allowing the full benefits of extensive and uniform air dilution to be achieved.

The filter shown in Figure 8 has a cavity 6 constituted by a gap between upstream and downstream filter sections I and II extending obliquely across the filter; the upstream and downstream faces of cavity 6 are thus essentially elliptical, and the cavity has a localised upstream peripheral extremity and likewise a localised downstream peripheral extremity.

According to my invention, I concentrate all or most of the air vents 7 at the said localised upstream peripheral extremity of cavity 6, which is where the flow of smoke into the cavity is also preferentially concentrated, so that I obtain immediate and extensive mixing of the smoke and the direct ventilation air. The arrows in Figure 8 indicate a possible general flow pattern for smoke through the filter, and it will be appreciated that with the arrangement shown a substantially uniform air/smoke mixture will be obtained from the exit end of the filter.

Figure 9 shows a similar embodiment, modified merely in that the cavity 6 of Figure 8 is replaced by a cavity which is V-shaped in longitudinal section with two diametrically opposed substantially equivalent upstream peripheral extremities; in this case the air vents 7 are concentrated wholly or partly at these two extremities.

Figure 10 shows another embodiment in which the cavity 6 is annular, the upstream and downstream faces of cavity 6 being conical; in this case, the upstream peripheral extremity of cavity 6 extends fully around the circumference of the filter, and the air vents 7 are disposed in a ring around the filter at this extremity.

The arrows in Figures 9 and 10 indicate possible flow paths of smoke through the filters concerned.

It will be appreciated that, in the accompanying drawings, the vents 7 are shown merely schematically. In particular, the size and number of vents 7 in each case will in practice be varied according to the degree of air dilution required, and is in no way restricted to that explicitly shown in the drawings.

The filter cigarettes according to the invention are ideally suited for marketing in e.g.

four types under one brand name, each type having a different percentage of tar in the smoke (a small increase in the size and/or the number of the air vents reduces the tar in the smoke), so that the smoker, if he wants to, can. without changing his brand, gradually lower his tar intake, in the way the MD-4 cigarette holders are suggested to be used (U.S. Patent No. 3.810.476).

Filters according to the invention are well suited to use in filter tubes for home-made cigarettes: such filtered tubes are provided in the form of an empty cylinder of cigarette paper closed at one end by a filter, the cigarette being made by the purchaser by filling the empty cylinder portion with tobacco.

In a quantitative test of a filter according to the invention, Rothmans (Registered Trade Mark) and Embassy (Registered Trade Mark) King Size filter cigarettes as commerically available were modified by altering the filters into the form illustrated in Figure 7; these modified cigarettes (obtained by removing the filters, separating the filter rod from each and heat-pressing its central portion to give a filter rod shaped as shown in Figure 7, and recombining the modified filters with the original cigarettes as shown in Figure 7), and the commercially available unmodified samples, were smoked and the results were compared. In the modified filter rods, the distance between the upstream and downstream extremities of the cavity 6 was 10 mm, and the wrappers 4 and 5 around the annular cavity 6 were perforated to give 80% air dilution.In most cases, these perforations or vents 7 were twenty in number, disposed uniformly around the circumference of the filter in two longitudinally spaced rings (10 vents in each) disposed symmetrically with respect to the cavity. On smoking, the unmodified commerically available cigarettes produced on average 20 mg of tar and 1.5 mg of nicotine, whereas the modified samples according to Figure 7 produced on average 3.6 mg of tar and 0.53 mg of nicotine; the filters according to the invention thus markedly reduced the tar content of the filtered smoke, whilst increasing the nicotine/tar ratio from 0.07 to 0.15. This impressive improvement was obtained with full maintenance of taste and smoothness of the inhaled smoke, and of acceptable draw characteristics.The unmodified filters of the commercially available cigarettes were of cellulose acetate, about 20 mm. long and 8 mm in diameter.

WHAT I CLAIM IS: 1. A tobacco smoke filter comprising a body of tobacco smoke filtering material, a wrapping forming a tubular wall around the body, at least one cavity defined and substantially wholly enclosed by the body and the wrapping and extending to the tubular wall, and air-permeable means in the wrapping allowing direct passage of external ventilating air into the cavity or cavities through the wrapping, the filter body constraining the smoke flow in the cavity or cavities to concentrate adjacent said tubular wall, and the air-permeable means being disposed at the region of concentrated smoke flow whereby at least a major portion of tobacco smoke and the ventilation air entering the cavity or cavities form a mixture over a region of the filter extending inwardly of its peripheral region.

2. A filter as claimed in Claim 1, wherein the or each said cavity has a shape causing a variation, across the filter, of the rate of smoke flow into the cavity.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. downstream filter sections I and II extending obliquely across the filter; the upstream and downstream faces of cavity 6 are thus essentially elliptical, and the cavity has a localised upstream peripheral extremity and likewise a localised downstream peripheral extremity. According to my invention, I concentrate all or most of the air vents 7 at the said localised upstream peripheral extremity of cavity 6, which is where the flow of smoke into the cavity is also preferentially concentrated, so that I obtain immediate and extensive mixing of the smoke and the direct ventilation air. The arrows in Figure 8 indicate a possible general flow pattern for smoke through the filter, and it will be appreciated that with the arrangement shown a substantially uniform air/smoke mixture will be obtained from the exit end of the filter. Figure 9 shows a similar embodiment, modified merely in that the cavity 6 of Figure 8 is replaced by a cavity which is V-shaped in longitudinal section with two diametrically opposed substantially equivalent upstream peripheral extremities; in this case the air vents 7 are concentrated wholly or partly at these two extremities. Figure 10 shows another embodiment in which the cavity 6 is annular, the upstream and downstream faces of cavity 6 being conical; in this case, the upstream peripheral extremity of cavity 6 extends fully around the circumference of the filter, and the air vents 7 are disposed in a ring around the filter at this extremity. The arrows in Figures 9 and 10 indicate possible flow paths of smoke through the filters concerned. It will be appreciated that, in the accompanying drawings, the vents 7 are shown merely schematically. In particular, the size and number of vents 7 in each case will in practice be varied according to the degree of air dilution required, and is in no way restricted to that explicitly shown in the drawings. The filter cigarettes according to the invention are ideally suited for marketing in e.g. four types under one brand name, each type having a different percentage of tar in the smoke (a small increase in the size and/or the number of the air vents reduces the tar in the smoke), so that the smoker, if he wants to, can. without changing his brand, gradually lower his tar intake, in the way the MD-4 cigarette holders are suggested to be used (U.S. Patent No. 3.810.476). Filters according to the invention are well suited to use in filter tubes for home-made cigarettes: such filtered tubes are provided in the form of an empty cylinder of cigarette paper closed at one end by a filter, the cigarette being made by the purchaser by filling the empty cylinder portion with tobacco. In a quantitative test of a filter according to the invention, Rothmans (Registered Trade Mark) and Embassy (Registered Trade Mark) King Size filter cigarettes as commerically available were modified by altering the filters into the form illustrated in Figure 7; these modified cigarettes (obtained by removing the filters, separating the filter rod from each and heat-pressing its central portion to give a filter rod shaped as shown in Figure 7, and recombining the modified filters with the original cigarettes as shown in Figure 7), and the commercially available unmodified samples, were smoked and the results were compared. In the modified filter rods, the distance between the upstream and downstream extremities of the cavity 6 was 10 mm, and the wrappers 4 and 5 around the annular cavity 6 were perforated to give 80% air dilution.In most cases, these perforations or vents 7 were twenty in number, disposed uniformly around the circumference of the filter in two longitudinally spaced rings (10 vents in each) disposed symmetrically with respect to the cavity. On smoking, the unmodified commerically available cigarettes produced on average 20 mg of tar and 1.5 mg of nicotine, whereas the modified samples according to Figure 7 produced on average 3.6 mg of tar and 0.53 mg of nicotine; the filters according to the invention thus markedly reduced the tar content of the filtered smoke, whilst increasing the nicotine/tar ratio from 0.07 to 0.15. This impressive improvement was obtained with full maintenance of taste and smoothness of the inhaled smoke, and of acceptable draw characteristics.The unmodified filters of the commercially available cigarettes were of cellulose acetate, about 20 mm. long and 8 mm in diameter. WHAT I CLAIM IS:

1. A tobacco smoke filter comprising a body of tobacco smoke filtering material, a wrapping forming a tubular wall around the body, at least one cavity defined and substantially wholly enclosed by the body and the wrapping and extending to the tubular wall, and air-permeable means in the wrapping allowing direct passage of external ventilating air into the cavity or cavities through the wrapping, the filter body constraining the smoke flow in the cavity or cavities to concentrate adjacent said tubular wall, and the air-permeable means being disposed at the region of concentrated smoke flow whereby at least a major portion of tobacco smoke and the ventilation air entering the cavity or cavities form a mixture over a region of the filter extending inwardly of its peripheral region.

2. A filter as claimed in Claim 1, wherein the or each said cavity has a shape causing a variation, across the filter, of the rate of smoke flow into the cavity.

3. A filter as claimed in Claim 2 wherein

the or each said cavity has an upstream peripheral extremity, said air-permeable means being concentrated at said extremity.

4. A filter as claimed in Claim 3 wherein the or each said cavity has an upstream wall extending obliquely downstream from said tubular wall.

5. A filter as claimed in claim 4 wherein said upstream wall tapers downstream from around said tubular wall.

6. A filter cigarette incorporating a filter as claimed in any of claims 1 to 5.

7. A tobacco smoke filter, or a filter cigarette, substantially as hereinbefore described with reference to Figure 1, 2 or 3 of the accompanying drawings.

8. A tobacco smoke filter, or a filter cigarette, substantially as herein before described with reference to Figure 4 or 5 of the accompanying drawings.

9. A tobacco smoke filter, or a filter cigarette, substantially as hereinbefore described with reference to Figure 7 of the accompanying drawings.

10. A tobacco smoke filter, or a filter cigarette, substantially as hereinbefore described with reference to Figures 8, 9 or 10 of the accompanying drawings.