Smoking device

Abstract

A smoking device, preferably in the form of a cigarette, has an inner lengthwise extending combustion zone and an outer combustion zone surrounding it and separated from it by a barrier, both zones containing particulate tobacco or the like. The inner zones comprises the major volume of the device and is blocked off at the mouthpiece end and the parts are arranged so that smoke from the burning end portion of tobacco in the blocked off zone is by-passed to the mouthpiece end through the other, minor volume, zone so that the products of combustion are not deposited and reburned in the first zone.

Description

My invention relates to smoking devices, such as cigarettes, cigars, and the like, but finds its greatest usefulness as a cigarette which provides palatible smoke containing only a controlled percentage of products of combustion deposited and reburned and redeposited and reburned in the tobacco as smoking proceeds.

For convenience in the specification and claims, the following terms have the meanings indicated:

"Tabacco" means finely cut tobacco or shredded reconstituted tobacco or other suitable particulate smoking material.

"Palatable smoke" means products of combustion acceptable to smokers, whether it be from tobacco or cigarette paper or other combustible components of the smoking device.

"Mainstream smoke" means smoke which is drawn from the lighted end portion of a charge of tobacco through that same tobacco, thereby depositing for reburning products of combustion therein. Mainstream smoke also usually contains at least some very unpalatable and even noxious smoke given off by the tobacco immediately adjacent the burning cone which has been sufficiently heated to smolder but is not yet burning, perhaps due to lack of oxygen more than lack of heat--resembling that given off by an insufficiently ventilated pile of damp burning leaves.

"By-pass smoke" means smoke which is drawn from the lighted end of a charge of tobacco through a separate channel, by-passing such charge of tobacco, so that such depositing and reburning are reduced.

Modern cigarette technology has concentrated its efforts on reducing undesirable substances in tobacco smoke reaching the smoker primarily by providing filters of various sorts, although a smoking device has also been suggested wherein the smoke from the lighted end can by-pass the unburned tobacco through an open central tube thus apparently reducing the depositing and reburning problem but at the same time creating a serious risk of flame and excessive heat reaching the smoker's mouth. Another approach which has been taken is to treat the cigarette paper in such a way that as smoking progresses toward the mouthpiece end the wrapper becomes more porous, thereby increasing the amount of air introduced to dilute the main stream smoke. This merely dilutes the smoke but does not reduce or eliminate undesirable substances already entrained therein.

The object of the present invention is the provision of an improved smoking device for by-pass smoking wherein the percentages of by-pass smoke and mainstream smoke can be controlled, the latter being virtually eliminated if desired, which will have drawing and burning characteristics closely approximating conventional smoking devices, which will not have a tendency to extinguish itself between puffs, and wherein the risk of flame and/or excessively hot gases running from the burning end through an unobstructed space toward the mouthpiece end is eliminated.

The invention features a device for by-pass smoking having an ignition end and a mouthpiece end, the device comprising a material holding wrapper defining a longitudinally extending space within itself. Within the space and extending essentially throughout the same is material at least some of which is combustible and capable of giving off palatable smoke when burned, the material including longitudinally extending barrier means dividing the space into inner and outer combustion zones. Control means are provided for controlling the percentage of mainstream smoke which can pass from the burning portion of the material in one zone through such zone to the mouthpiece end and means are provided for maintaining a predetermined spaced relationship between the burning portions of the material in both zones as smoking progresses so that when the smoker draws on the device at least some air currents caused by the draught will pass through the burning portion of the combustible material in one zone and carry smoke therefrom into and through the other zone, by-passing the said one zone, to the mouthpiece end of the device.

In preferred embodiments the first named wrapper is of combustible material, the material providing the longitudinally extending barrier which divides the interior space into two combustion zones comprises an inner wrapper of combustible material, the control means comprises an obstruction at the mouthpiece end of the zone through which the passage of mainstream smoke is to be controlled, and the means for maintaining the predetermined spaced relationship between the burning portions of the combustible material in each zone includes the combustible material between the inner and outer wrappers which material may be tobacco or portions of either or both wrappers, such as longitudinally extending closely spaced ribs formed thereon. The zone within the inner wrapper comprises a major volume of the device and the zone between the wrappers comprises a minor volume of the device and forms a channel for by-pass smoke from the burning end of the material in the other zone to the mouthpiece end.

In all forms of the invention I may provide either a mouthpiece or a filter attached to the mouthpiece end arranged so that by-pass smoke will pass through it to the mouth of the smoker. The barrier to the passage of mainstream smoke may be smoke obstructing means within the mouthpiece or, in the case of a filter, a portion of the filter surface which is made resistive of impermeable to the passage of smoke.

In those forms of the invention where a mouthpiece or filter is employed the same may be affixed to the remainder of the device by tipping paper, and the latter arranged to conduct by-pass smoke from the by-pass channel to the interior of the mouthpiece, or, in the case of a filter, to a smoke permeable portion of the filter. In the case of the filter a smoke resistant or smoke impermeable portion of the filter surface acts as the obstruction to passage of mainstream smoke.

I prefer to employ in both combustion zones of the device a particulate combustible material which may comprise finely cut tobacco or shredded reconstituted tobacco. In one form of the invention such particulate tobacco material fills the zone which comprises the major volume of the device and portions of one or both wrappers essentially fill the other zone. In still another form of the invention the wrapper which defines the inner combustion zone and major volume of the device is in the form of a cartridge filled with tobacco, closed at least at its mouthpiece end, the closed portion thereof comprising the obstruction to the passage of mainstream smoke to the mouthpiece end.

In all forms of the invention, optionally, I may arrange the obstruction to permit a predetermined percentage of mainstream smoke to pass the mouthpiece end of the device to mix with the by-pass smoke.

A presently preferred embodiment employs inner and outer wrappers of cigarette paper or reconstituted tobacco, with the space within the inner wrapper defining the major volume of the device and the principal combustion zone, while the space between the wrappers defines a minor volume and the secondary combustion zone. Tobacco fills both zones. An obstruction blocks all or a desired portion of the mouthpiece end of the principal combustion zone. The mutual spacing and burning rates of the two wrappers and the density and combustibility of the tobacco are so chosen that as smoking progresses the burning portion of the tobacco in the secondary zone maintains a predetermined relationship with the burning cone of tobacco in the principal combustion zone, so that when the smoker draws on the device at least some air currents caused by the draught will pass through the burning cone of tobacco in the principal zone and will carry therefrom into and through the secondary zone, by-passsing the principal zone, to the mouthpiece end of the device.

At the ignition end of the device, optionally I provide perforations in the inner wrapper to facilitate lighting. The inner wrapper likewise may be made shorter than the outer wrapper, having its end spaced inwardly from the end to be lighted, and the space between its end and the adjacent end of the outer wrapper filled with tobacco filler, both to facilitate lighting and to enhance the flavor of the first puffs.

As an alternative to the use of only a partial obstruction to provide both mainstream and by-pass smoke to the mouthpiece end, I may provide an inner wrapper having longitudinal portions having a higher burning rate than the remaining portions, so as to provide gaps after the device is lighted through which some smoke from the lighted end may pass, and thence be drawn through at least some tobacco filter en route to the space between the wrappers from where it passes on to the mouthpiece end.

The burning rates of the inner and outer wrappers are regulated in a manner known in the art, as by using tobacco paper of different thicknesses, density, or porosity, or the application of flame accelerating or retarding materials thereto.

In the annexed drawings illustrating preferred embodiments of the invention:

FIG. 1 is a partially broken away perspective view of a cigarette according to the invention;

FIG. 2 is a similar view of an alternative construction;

FIG. 3 is an enlarged section of a portion of another form of a cigarette taken through the longitudinal axis;

FIG. 4 is a section on line 4--4 of FIG. 3;

FIG. 5 is a longitudinal sectional view of a further modified form;

FIG. 6 is a longitudinal section on an enlarged scale of the ignited end of the cigarette of FIG, 5 showing by arrows the air and smoke flow paths;

FIG. 7 is a view similar to FIG. 6 but on a smaller scale of another embodiment;

FIG. 8 is a view similar to FIG. 3 of a cigarette employing a filter at the mouthpiece end;

FIG. 9 is an exploded view of still another form of filter cigarette;

FIG. 10 is a section on an enlarged scale of the filter end of the device of FIG. 9;

FIG. 11 is a view similar to FIG. 9 of still another modification;

FIG. 12 is a view similar to FIG. 10 of the device of FIG. 11;

FIG. 13 is an exploded view partly in longitudinal section of still a further modified cigarette employing a disc having a flexible peripheral portion as the obstructing means; and,

FIG. 14 is an enlarged sectional view of a portion of the assembled cigarette of FIG. 13.

As shown in FIG. 1, a cigarette for by-pass smoking according to the invention includes combustible smoking material such as tobacco 10 and a conventional outer wrapper 12 of cigarette paper. Disposed within the outer wrapper 12 is an inner wrapper 14 which encloses the tobacco filler 10. The mouthpiece end of the inner wrapper 14 is sealed off as at 16 by wax or other suitable material to provide an obstruction or barrier which limits, or completely prevents, the passage of mainstream smoke therethrough. A member 18, having perforations 20 therein, is provided to separate the main portion of the cigarette from the mouthpiece itself 22 which is held to the cigarette proper by tipping paper 44. The mouthpiece 22 may or may not include a filter medium such as is well known in the art.

Combustible material yielding palatable smoke forms spacing means 24 between the outer and inner wrappers. While the medium 24 may be chosen from a broad range of materials I prefer a discontinuous combustible material of a "pebbly" or "grainy" nature, such as shredded tobacco or reconstituted tobacco, so as to provide virtually continuous support for the outer wrapper while at the same time to provide a passage for by-pass smoke longitudinally along the annular channel between the inner and outer wrappers. For example, particulate matter, such as shredded reconstituted tobacco (RTP), may be adhered to the outer surface of the inner wrapper or to the inner surface of the outer wrapper as the elements are assembled.

The inner wrapper 14 may, if desired, be provided with perforations 26 near its outer or ignition end 28. The perforations 26 have been found to be desirable to increase the air flow through the tobacco 10 itself at the instant of lighting, thereby to make the cigarette easier to light.

Alternatively, the inner wrapper 14d may be somewhat shorter than the outer wrapper 12d so that end 28d is withdrawn into the body of the cigarette, as shown in FIG. 7. This structure also provides improved lighting characteristics and may enhance the flavor of the first few puffs because of the presence of the extra tobacco 60 at the outer end.

FIG. 2 illustrates a cigarette construction having a recessed inner wrapper 14a, provided with a multitude of longitudinally extending corrugations forming the combustible spacing medium in the by-pass channel. The spaces between the outer wrapper 12 and the "valleys" 32 of the outward-facing corrugations of inner wrapper 14a provide a direct route for by-pass smoke from the burning end of the cigarette to reach the smoker without passing through the unburned tobacco 10 within the inner wrapper. It is thus apparent that the means for maintaining the separation of the inner and outer wrappers may simply be the numerous ridges or "hills" of corrugations on the inner wrapper. Alternatively, the inner wrapper could be embossed upon only its outer surface or a separate corrugated or embossed layer of material (e.g., RTP) could be disposed between smooth inner and outer wrappers. In all cases the support given to the outer wrapper by its contact with the surface of the supporting medium must be sufficiently uniform to prevent undesirable running of flame down the outer wrap.

FIGS. 3 and 4 show another variation in which the inner wrap 14a is similar to that in FIG 2, that is fluted to provide the support for the outer wrapper, and employing a filter. The filter 22b has a sealing projection 48 and the by-pass smoke passes through a pervious annular portion of the filter as indicated by the arrow 47 in FIG. 3. The parts are held together by tipping paper 44. Opening 49 permits a predetermined portion of mainstream smoke to enter the filter and blend with the by-pass smoke.

FIG. 5 illustrates a cigarette construction similar to that of FIG. 1 but including simplifications which are presently thought to make the manufacture of the cigarette more compatible with existing cigarette making machinery. Once again tobacco 10 is disposed within an inner wrapper 14c. An outer wrapper 12 is separated from the inner wrapper 14 by a medium 24, which is preferably finely cut tobacco or reconstituted tobacco particles as in FIG. 1. In place of the sealed end 16 of inner wrapper 14 and perforated barrier 18 as in FIGS. 1 and 2, a plug 34 is disposed in mouthpiece 22c adjacent the open end 20a of the inner wrapper. The mouthpiece is attached by means of tipping paper 44. The plug may be of any material which is impervious to the smoke of burning tobacco. The plug 34 may, if desired, obstruct less than the entire cross-sectional area of the open end 20a of the inner wrapper. A convenient way to achieve this is to make the plug 34 in cylindrical form with its axis aligned with that of the cylindrical inner wrapper 14, but having a diameter less than that of the wrapper 14. In this a predetermined percentage of mainstream smoke may be blended with by-pass smoke.

The plug 34 may be maintained in the correct orientation within the mouthpiece 22 by means of a plurality of radially extending fins 35 which contact the cylindrical mouthpiece 22c.

FIG. 6 shows the flow-paths which the air and smoke are believed to follow at the lighted end of the novel smoking device of the embodiments just described from which illustration the principle of operation of the invention becomes apparent. When the smoker draws on the cigarette, a current of air is drawn through the space between the wrappers. If the outer end of the outer wrapper extends at least as far as the burning cone of tobacco, this draught will produce air flow through the burning cone 10a and into the by-pass space between the wrappers, as shown by the arrows. This causes the cone and adjacent wrappers and spacing medium 24 to glow. Smoke produced by the cone 10a by-passes the tobacco filler 10 and flows through the space between the wrappers to the mouthpiece end of the cigarette. It is clear that the presence of this outwardly-extending portion of the outer wrapper is essential to the functioning of the cigarette; but for it no air currents would be set up by drawing on the cigarette which would influence the burning of the cone. Stated in another way, if the entrance to the passage between the wrappers is too remote from the flame, a draught set up therein will neither cause burning nor pull any smoke into the by-pass channel between the wrappers.

To achieve this desired projection of the end of the outer wrapper to at least partially surround the burning cone of tobacco, it is necessary to select its "burning rate" as less than that of the inner wrapper. By this is meant not necessarily the relative burning rates of the materials in open air, but their effective burning rates in the environment of the particular cigarette construction. Thus the effective burning rate of the outer wrapper is affected by its proximity to the inner wrapper as well as by the nature, including combustibility, and compactness, of the combustible materials 10 and 24. The proximity of the outer wrapper to the inner wrapper is not merely a function of relative initial diameters, but also may change as the cigarette is smoked because of pressure differential induced by the smoker's drawing on the cigarette. This effect is subject to a number of variables, including original spacing from the inner wrapper, permeability and stiffness of the wrapper, and the support afforded by the spacing medium. It may be said, generally, that the closer the outer wrapper is to the inner wrapper, the more nearly they will burn at the same speed in spite of different absolute burning rates. On the other hand, the channel between them must remain sufficiently open always to permit the passage of the by-pass smoke with the desired pressure drop. However, the support afforded the outer wrapper must be substantially continuous, for the flame will travel undesirably down any unsupported area of the outer wrapper. Having in mind the teachings of the invention, the skilled cigarette maker will be able to achieve a nice balancing of the relevant factors so as to produce a satisfactory cigarette for by-pass smoking according to the invention.

In FIG. 8 there is shown still another embodiment. In this case the filter 22d is heat-sealed at 46 to provide a smoke impermeable barrier. Its cylindrical outer surface however is porous, and may be smoke permeable paper. The tipping paper 44e is embossed. This form of the invention depends for its success on the fact that the filter will be imperfectly sealed against the inner end of the outer wrapper 12e. Drawing on the cigarette will produce quite sufficient leakage around the inner edge of the outer wrapper so that by-pass smoke will travel, as shown by the arrows, out from under the inner wrapper 14e, through channels provided by the embossed tipping paper, and back in through the porous wall of the filter 22d to the smoker's mouth. In this case the embossed tipping paper is of course glued in sealing relation to the outer wrapper only at its forward portion and to the surface of the filter at its inner portion, as indicated at 54 and 56.

FIGS. 9 and 10 show two alternative structures for permitting substantially only by-pass smoke to reach the filter 22f. The inner end of the outer wrapper 12f is perforated as at 40 as is the outer portion of the filter as at 42. An embossed tipping paper 44f mounts the filter to the cigarette proper and it is sealed to the wrapper 12f at its outer edge and to the filter along its inner edge. By-pass smoke will pass out through the gap at the base of outer wrapper 12f, along the passages inside the embossed tipping paper and into the openings 42 as indicated by arrows. The forward end 46f of the filter 22f is made impervious by heat sealing, as in the embodiment of FIG. 8.

FIGS. 11 and 12 show still another embodiment wherein the filter 22g is provided with an outwardly projecting cylindrical portion 48 which is impervious to smoke. When the parts are assembled by tipping paper 44g this portion is wedged into the tobacco in the inner wrapper 14g and acts as a barrier to prevent mainstream smoke from reaching the filter. By-pass smoke passes from between wrappers 12g and 14g through permeable face 46g of filter 22g as indicated by the arrows in FIG. 12.

FIGS. 13 and 14 show another variation wherein a filter 22h, similar to that of FIG. 11, but with an arcuate permeable forward surface 52, is assembled by tipping paper 44h to the main cigarette comprising inner wrapper 14h, outer wrapper 12h, main tobacco charge 10h and minor tobacco charge 24h. A smoke impermeable disc 50 of flexible material is interposed between the filter and the cigarette and its outer rim will flex, when the smoker draws on the cigarette, down into the channel produced by the portion 52, thus permitting by-pass smoke, but not mainstream smoke, to pass through the filter.

While by-pass smoke contains the lowest percentage of products of repeated deposition and reburning of products of combustion, it is clear nevertheless that substantial advantages of the invention are still present if a predetermined portion of mainstream smoke is allowed to mix with by-pass smoke. Furthermore, by varying the percentage of the portion, the taste and drawing properties of the cigarette may be tailored to satisfy a wide range of preferences.

One way to adjust the relative percentages of mainstream and by-pass smoke is to provide a partially pervious obstruction, such as plug 34 in FIG. 5, for the cylinder of tobacco filler 10. This may be accomplished in the embodiments of FIGS. 1 and 2 by making the sealed end 16 of the inner wrapper only somewhat resistant to the passage of smoke, thereby inducing the bulk of the smoke to flow in the by-pass channel(s) at the periphery of the cigarette. In the embodiment of FIG. 5, the diameter of the plug 34 may, as already mentioned, simply be varied, instead of varing its porosity.

As a second way to provide some mainstream smoke to the mouthpiece, the inner wrapper, in the embodiments such as those of FIGS. 1 and 2, may be constructed to have longitudinal strips which burn at a faster rate than the remainder of the inner wrapper to permit at least a portion of the smoke to pass through some unburned tobacco. Since the percentage of the total inner wrapper area which burns faster may be varied, the amount of smoke which travels through the tobacco may be adjusted to any taste. The faster burning strips may be produced by treatment of the paper of the inner wrapper, by embossing to provide thinner paper in those strips, or by any conventional technique.

Examples of additives to tobacco paper which are used to influence their burning rates are citrate salts to increase the rate of phosphates to slow the rate. Also, the addition of inert materials to the paper will slow the burning rate. More porous papers burn more quickly; denser papers, more slowly.

While no exact limits can be stated because flame transfer between inner and outer wraps depends not only on mutual spacing but also on the nature, density, and burning rate of the media between and within them, generally speaking I have found that utilizing cigarette papers 0.001 inch thick for both inner and outer wrappers in a FIG. 1 embodiment for example, and reconstituted tobacco particles adhered to the outer surface of the inner wrap, excellent results are obtained with a gap of about 0.0125 inch between inner and outer wrappers. This cigarette had excellent drawing qualities. It was noted that even after the cigarette was smoked all the way down, the filter in the mouthpiece remained clean, in marked contrast to the condition of a similar filter of an ordinary filter-tip cigarette. The last puff was just like the first puff so far as flavor, aroma, and quality were concerned. In contrast a spacing of 0.030 inch appears to be too great, and in most cases the cigarette would go out after lighting and could not be kept lit even by drawing on it. This cigarette had poor drawing qualities.

Claims

What is claimed is:

1. In a smoking device having an ignition end and a mouthpiece end and including an outer wrapper surrounding an elongated main charge of smoking material, an annular passage defined in part by said outer wrapper to conduct smoke from the burning cone of material directly to the mouthpiece end by-passing the main charge, and control means for limiting the passage of main-stream smoke from the cone through the main charge to the mouthpiece end, the improvement which comprises

means for supporting said outer wrapper at a plurality of spaced areas in such predetermined spaced relationship in transverse direction to the main charge that drawing on the device will cause flame transfer between the main charge and the outer wrapper, carry by-pass smoke through the passage to the mouthpiece end and at the same time hold the outer wrapper against collapsing onto the charge to pinch off the passage,

the outer wrapper being composed of combustible material having a slower burning rate than that of the main charge so that the burning rim of the outer wrapper will extend outwardly at least as far as the burning cone of the charge as smoking progresses such that smoke substantially to the exclusion of ambient air will be drawn down the passage on each draught by the smoker, and

the mutual spacing of said supporting means being uniform and close, whereby the running of the flame down the wrapper is prevented.

2. The device of claim 1 including a mouthpiece affixed to the mouthpiece end of the device and wherein smoke impermeable means in said mouthpiece comprises said control means.

3. The device of claim 1 including a filter affixed to the mouthpiece end of said device, at least a portion of the surface of said filter being resistant to passage of smoke and comprising said control means.

4. The device of claim 1 including a filter affixed to the mouthpiece end of said device by means of tipping paper at least a portion of the end of said filter which is adjacent the remainder of said device being resistant to passage of smoke and comprising said control means, another portion of the periphery of said filter being permeable to smoke, and the tipping paper being spaced from the permeable portion of the filter to provide a passage for by-pass smoke to said permeable portion.

5. The device of claim 1 wherein said control means is arranged to permit a predetermined percentage of mainstream smoke to pass to the mouthpiece end of the device to mix with the by-pass smoke.

6. The device of claim 1 wherein said control means is arranged to permit a predetermined percentage of mainstream smoke to pass to the mouthpiece end.

7. The device of claim 1 wherein the outer surface of the main charge is provided with longitudinally extending corrugations to provide ribs which comprise at least in part said supporting means.

8. The device of claim 1 wherein said main charge comprises a tobacco product surrounded by an inner wrapper whose outer surface with the inner surface of said outer wrapper defines said passage, and wherein the means for supporting said outer wrapper includes a minor charge of smoking material held within said passage between said wrappers.

9. The device of claim 8 wherein the inner wrapper is in the form of a cartridge, closed at least at its mouthpiece end, the closed portion thereof comprising said control means.

10. The device of claim 8 wherein said inner wrapper is provided with perforations near the ignition end of the device to facilitate lighting.

11. The device of claim 8 wherein the inner wrapper is shorter than the outer wrapper and has its ignition end spaced inwardly of the ignition end of the device, the space between its end and the adjacent ignition end of the device being filled with tobacco to facilitate lighting and enhance the flavor of the first puffs.

12. The device of claim 8 wherein the combustible material in the zone between said wrappers comprises portions of at least one of said wrappers.

13. A smoking device for by-pass smoking having an ignition end and a mouthpiece end, comprising

inner and outer wrappers of suitable combustible material,

the inner wrapper defining within itself a principal combustion zone comprising a major volume of the device and the two wrappers defining between them a secondary combustion zone comprising a minor volume of the device,

tobacco essentially filling each zone, and

smoke obstructing means associated with the mouthpiece end of said principal combustion zone for limiting the percentage of mainstream smoke with will pass therethrough to the mouthpiece end of the device,

the mutual transverse spacing and burning rates of the two wrappers and the density and combustibility of the tobacco which separates them being so chosen that as smoking progresses the burning portion of the tobacco in said secondary zone maintains a predetermined longitudinal relationship with the burning cone of tobacco in said principal zone, so that when the smoker draws on the device at least some air currents caused by the draught will pass through said burning cone and will carry smoke therefrom into and through said secondary zone, by-passing said principal zone, to the mouthpiece end of the device.