US3774622A

US3774622A - Device,particularly a cigarette,for smoking a cord of smokable material

Info

Publication number: US3774622A
Application number: US00199136A
Authority: US
Inventors: K Steigerwald
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-11-16
Filing date: 1971-11-16
Publication date: 1973-11-27
Anticipated expiration: 1990-11-27

Abstract

A cigarette has at least one longitudinal secondary air channel which is sealed towards the suction end of the cigarette and is in communication with the ambient air via a connection separated from the suction path of the smoke.

Description

United States Patent [1 1 Steigerwald Nov. 27, 1973 DEVICE, PARTICULARLY A CIGARETTE,

FOR SMOKING A CORD OF SMOKABLE MATERIAL [76] Inventor: Karl Heinz Steigerwald,

Pringeneiche 15, Starnberg, Germany [22] Filed: Nov. 16, 1971 [21] Appl. No.: 199,136

[52] US. Cl 131/9, 131/8 R, 131/10 A, 131/10.5, 131/193, 131/198 A [51] Int. Cl. A24d 01/02, A24f 01/02, A24f 05/04 [58] Field of Search 131/8 R, 8 A, 9, 131/10 A, 10.5, 4 B, 198 R, 198 A, 261 B,

[56] References Cited UNITED STATES PATENTS 3,674,036 7/1972 Vega 131/10 A X 492,676 2/1893 Harris 131/8 X 1,778,482 10/1930 Burns 131/8 R X 3,389,705 6/1968 Levavi 131/9 X 2,575,488 11/1951 Carlson... 131/195 2,354,712 8/1944 Stieger 131/195 FOREIGN PATENTS OR APPLICATIONS 1,905,273 8/1970 Germany 131/8 R 1,914,963 10/1970 Germany..... 131/8 R 577,635 6/1958 Italy 131/9 Primary ExaminerRobert W. Michell Assistant Examiner-John F. Pitrelli Att0rneyJoseph M. Fitzpatrick et a1.

[57] ABSTRACT A cigarette has at least one longitudinal secondary air channel which is sealed towards the suction end of the cigarette and is in communication with the ambient air via a connection separated from the suction path of the smoke.

27 Claims, 20 Drawing Figures Patented Nov. 27, 1913 3.774522 4 Sheets-Sheet 1 Fig.1

Patented Nov. 27, 1973 4 Sheets-Sheet 2 Patented Nov. 27, 1973 4 Sheets-Sheet 3 Fig.5

Fi .1z.

Patauted Nov. 27, 1973 4 Sheets-Sheet 4 Fig.1?

Fig.18

Fig.19

DEVICE, PARTICULARLY A CIGARETTE, FOR SMOKING A CORD OF SMOKABLE MATERIAL FIELD OF THE INVENTION The invention relates to a device, particularly a cigarette, for smoking a cord or filler of smokable material, particularly tobacco, said device comprising a wrapper surrounding the cord or filler of smokable material and being adapted to be progressively destroyed in correspondence with the progress of the smoking process.

In a device of this kind, primary combustion air is conducted upon smoking by sucking at the suction or mouth end of the cord through the combustion zone produced by ignition at the other end of the cord. An oxygen deficit exists in the inner ranges of the combustion zone whereby an incomplete combustion including a dry distillation of the smokable material takes place there. The gas current which finally leaves the mouth end of the cord and is taken up by the smoker is laden with that proportion of the distillation and combustion products which has not been absorbed in the still unbumt portion of the cord (and possibly a separate filter added thereto). It is known that in the above-described combustion process the smoke will contain combustion and distillation products which are undesirable, tastedeteriorating and/or hazardous to health, for instance nicotin, carbon monoxide, tar, tar afterproducts, etc. Furthermore, it is known that the concentrations of such undesirable smoke constituents can be reduced if provision is made to make the combustion more complete and/or to dilute and cool the smoke by supplying secondary or bypass air. In the simplest case, the secondary air is sucked into the cord via openings provided in the wrapper. In order to avoid excessive dilution of the smoke in such an arrangement, it has been proposed to arrange the openings in the wrapper only in the vicinity of the suction end. This, however, has the disadvantage that the action of the secondary air merely consists in dilution of the smoke and this dilution takes place at locations where the smoke has already cooled down to a substantial extent whereby it is no longer possible to obtain any appreciable additional condensation of smoke constituents by means of a temperature decrease effected by the secondary air. In order to obtain better utilization of the secondary air, both for making the combustion more complete and for cooling the still hot combustion products immediately after combustion, it has further been proposed to pro vide passages in the wrapper, which are sealed by a sealing material selected to become ineffective at elevated temperatures. This has the result that the secondary air is supplied through the wrapper only in the vicinity of the combustion zone. The secondary air which is sucked in in that manner intermingles with the still hot smoke and cools the smoke, whereby an increased proportion of the smoke constituents will be condensed out of the smoke before the smoke passes through the still unbumt remainder of the cord to the suction end.

' Although according to this known measure the intake of the secondary air is substantially concentrical with the combustion zone, only a relatively small proportion of the secondary air really reaches the hot innermost range. This is due to the fact that the pressure differentials which are available for the intake of the secondary air in the range of the combustion zone are only very small and thus comparatively large openings or passages have to be formed in the wrapper in order to obtain an appreciable effect. In any case, however, the flow velocity of the entering secondary air is very small so that the secondary air is rapidly distributed in the cord material and cannot reach the innermost ranges of the cord where the largest oxygen deficit exists in the combustion zone.

According to another prior proposal, the passages provided in the wrapper are formed as valve flaps which open themselves under the influence of the approaching combustion zone and give the entering flow of secondary air a desired preferential direction. While this arrangement provides both for increased intake cross-section and for better guidance of the secondary air, the extent to which the concentrations of the mainly interesting deleterious smoke constituents can be reduced in this manner is still limited to no more than 30 to 40 per cent. This is due to the already mentioned fact that necessarily a considerable proportion of the introduced secondary air is merely admixed as diluting air to the smoke, and it was hitherto not possible to decisively reduce that portion in relation to the portions which are effective for cooling and combustion.

This, however, is necessary if the concentrations of the undesirable constituents of the smoke shall be reduced to a greater extent than hitherto possible without diluting the smoke so far that the taste of the smoke will become flat and unacceptable for a smoker.

Furthermore, the above-described prior embodiments employing a wrapper having passages which are opened only under the influence of an approaching combustion process, are disadvantageous in that, due to the large cross-sections of the passages as necessitated by the small available pressure differentials, the cigarette will be relatively sensitive to dirtying and hard handling. Moreover, there may be' appreciable discontinuities in the smoking process.

It is an object of the present invention to provide a device of the kind as initially indicated, which is free of the above-described disadvantages of the prior devices and makes possible, as compared with a similar device wherein no supply of secondary air is provided, a substantial reduction of undesirable smoke constituents without making the taste of the smoke unacceptably flat.

SUMMARY OF THE INVENTION To accomplish this object, the present invention provides a device of the kind as initially indicated, which device is characterized by at least one secondary air chanel extending lengthwise of the cord over at least part of the cord length, said secondary air channel being sealed against the mouth end and open towards the other end of the cord, and being at least partly sealed at its circumference against the cord of smokable material by sealing means which progressively lose their sealing properties under the influence of the combustion process which proceeds along the cord during the smoking process.

In the device according to the present invention, the secondary air can unimpededly enter through the secondary air channel which is open towards the end of the cord which is to be ignited, whereby comparatively large amounts of secondary air are made available even by the very small driving pressure differentials which are available in the region of the combustion zone. Since the secondary air channel is substantially sealed towards the mouth end as well as towards the still unburnt cord of smokable material, the said relatively large amounts of secondary air can enter the cord material only in or in the vicinity of the combustion zone, and since the secondary air channel can be arranged in the interior of the cord, it is readily possible to introduce the secondary air predominantly into the inner areas of the combustion zone and/or the immediate vicinity thereof where the oxygen deficit and the temperature of the smoke, respectively, are highest.

It has been found that a decisive improvement with regard to the reduction of undesirable smoke constituents can be obtained with the device according to the present invention; reductions of 50 or 60 percent and even more are possible without making the taste of the smoke unacceptably flat. As may be theorized, this favorable result is presumably due to the fact that in the device according to the present invention, the proportion of the secondary air which merely serves to cool and dilute the smoke can be reduced to a larger extent than hitherto possible, thus increasing that portion of the secondary air which serves to make the combustion more complete and to cool the smoke in zones where its temperature is highest.

A particularly simple embodiment of the device according to the present invention is characterized in that the end of the secondary air channel is closed which is nearer to the suction or mouth end of the cord. In that case, all the secondary air enters the secondary air channel from the other end of the cord. It has been found that normally the free cross-section formed by the secondary air channel is to a large part maintained in the combustion zone and its residual ash cone. This is particularly true if the surface of the channel is stabilized by suitable means so that the secondary air can reach the innermost portion of the combustion zone without losing oxygen to an objectionable degree when passing the more outwardly disposed portions of the combustion zone. In this embodiment, the cooling action of the secondary air is less distinctive.

As even more favorable behaviour, particularly with regard to improved cooling action, may be obtained according to a further development of the invention, which is characterized in that the secondary air channel comprises a connection to the ambient air in the range of its end which is nearer to the mouth end of the cord, the connection being separated from the suction path for the smoke. By this separate ambient air connection, secondary air can enter the secondary air channel without having to pass the combustion zone. Then, this secondary air arrives with its full oxygen content and in a comparatively cold condition at the inner ranges of the combustion zone or the vicinity thereof. As compared therewith, the proportion of the secondary air entering from the forward end of the cord through the combustion zone can be kept small because normally an increased flow resistance will be presented by the residuals of the secondary air channel in the outer areas of the combustion zone and its ash cone, which resistance is for example created by the presence of ash particles. Such increased flow resistance in the forwardmost portion of the secondary air channel can also be deliberately favored, for example by selecting a corresponding tobacco brand, by avoiding stabilizing agents in the surface of the secondary air channel, or by utilizing sealing means which tend to create a barrier or even a complete congestion in the secondary air channel upon smoking.

In the device according to the present invention, it is principally possible without difiiculties to adapt the parameters, particularly the channel diameter, which are determining for the flow resistance of the secondary air channel to the desired supply of secondary air and, moreover, if necessary, to make provision that the supply of secondary air varies in a desired manner, e.g., increases, as the combustion process proceeds. A further principal advantage of the device according to the invention resides in the fact that the secondary air channel can be provided in each case at the most suitable location in the cross-section of the cord, particularly in the zone of the cord axis, and that also a plurality of secondary air channels may be distributed over the cross-section of the cord.

It should be mentioned that it has frequently been proposed to provide longitudinal channels in devices of the kind initially indicated, particularly in cigars. However, these prior teachings lack the features which are decisive for the favorable action of the device according to the present invention. For example, it is known to provide cigars with draft passages in the form of throughgoing channels which are produced in the cord simply by shaping operations, e.g., by a drilling operation, and which are not sealed towards the cord material. This has the inherent disadvantage that the air which enters the throughgoing channel upon sucking on the cord will have no reason whatsoever to pass predominantly through the inner ranges of the combustion zone. Moreover, at least part of the smoke produced will pass directly to the mouth end without being filtered; this is disadvantageous as regards the temperature and the taste of the smoke leaving the cord. In another known cigar wherein a draft passage is provided which does not extend over the whole length of the cigar, a residual part of the cord length remains available for a filtering action; however, there remains the principal disadvantage of all throughgoing channels that the air aspirated through the channel is not enforced to pass through the combustion zone.

Developments of the invention are described in the dependent claims. Advantages of the invention and its developments will further become apparent by way of example from the subsequent description of embodiments, taken in conjunction with the drawings, with all features difi'ering from the prior art possibly being of essential importance for the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic longitudinal sectional view of a filter cigarette in accordance with the present invention.

FIG. 2 shows in a view similar to FIG. 1 another embodiment of a filter cigarette in accordance with the present invention.

FIG. 3 is an exploded partial view of the suction end of the cigarette shown in FIG. 2, with the cigarette being rotated by about its axis.

FIG. 4 is an axial view of the connector body shown in the center of FIG. 3, as viewed from the right in FIG. 3.

FIG. 5 illustrates the mouth end of the cigarette shown in FIG. 2, seen in the direction of the arrow V in FIG. 2.

FIG. 6 illustrates a modified embodiment in a partial view corresponding to FIG. 5.

FIG. 7 is a longitudinal sectional view of another embodiment of a filter cigarette in accordance with the present invention.

FIG. 8 is a schematic longitudinal sectional view of another embodiment of a filter cigarette in accordance with the present invention.

FIG. 9 is a sectional view along the line IXIX of FIG. 8.

FIG. 10 is a schematic partial longitudinal sectional view of another embodiment of a filter cigarette in accordance with the invention.

FIG. 1 1 illustrates in a schematic cross-sectional view another possible embodiment of a cigarette in accordance with the invention.

FIG. 12 is a schematic partial longitudinal sectional view of another embodiment of a cigarette in accordance with the invention.

FIG. 13 is a schematic cross-sectional view along the line XIIIXIII of FIG. 12.

FIG. 14 is a schematic longitudinal sectional view of another embodiment of a filter cigarette in accordance with the invention.

FIG. 15 is a cross-sectional view along the line XV-XV of the cigarette illustrated in FIG. 14.

FIG. 16 is a schematic partial longitudinal sectional view of another embodiment of a device in accordance with the present invention.

FIG. 17 illustrates in a partial longitudinal sectional view similar to FIG. 16 another embodiment of a device in accordance with the present invention.

FIG. 18 is a schematic view of an embodiment of a layer serving for mutual delimitation between the cord and the secondary air channel.

FIG. 19 is a sectional view along the line XIXXIX of FIG. 18.

FIG. 20 is a sectional view corresponding to FIG. 19 but shows another embodiment of a layer serving for mutual delimitation between the secondary air channel and the cord.

DETAILED DESCRIPTION OF THE DRAWINGS In the figures, cigarettes are shown as embodiments of the invention, it being understood, however, that the measures described are also applicable in other smoking devices, e.g., in cigars.

FIG. 1 shows in a longitudinal sectional view a filter cigarette including a cord 2 of tobacco or other smokable material, the cord being surrounded by a wrapper 4. The wrapper consists of a material which upon smoking will be destroyed in accordance with the progress of the smoking process, for instance cigarette paper or a substance which had been sprayed in liquid form onto the cord 2 and has solidified to form a continuous film. A filter 6 is connected in the usual manner to the suction end of the cord 2, the filter consisting of a filtering material 8, e.g., corrugated paper, and a filter sleeve 10. A connecting sleeve 12 glued to the filter sleeve 10 and the adjacent end of the wrapper 4 forms a connection between the filter and the cord.

A secondary air channel 14 extends in the axis of the cord 2. On its circumference, this secondary air channel I4 is at least partly sealed towards the cord of smokable material by sealing means which under the influence of the combustion process proceeding along the cord upon smoking progressively lose their sealing properties. Such sealing means are preferably formed by a layer 16 of a material which is combustible or adapted to be changed by the influence of heat. This material, for example, can have similar properties as the material which is used for the wrapper 4. It is particularly simple to use a layer 16 which consists of a sheet-like sleeve which preferably comprises a smokable material, for instance cigarette paper or tobacco foil. Another possibility is to provide the layer 16 bordering the secondary air channel 14 by the aid of a substance which enters into bonding relation with the cord material. For instance, in the production of the cigarette illustrated in FIG. 1, first the sleeve-like tobacco cord 2 may be formed, and thereafter the interior surface of this cord may be treated with a solution of cellulose acetate or another bonding agent until the desired sealing effect is obtained.

In the embodiment illustrated in FIG. 1, the end of the secondary air channel 14 which is nearer to the suction end of the cord 2 is closed by means of a closure body 18 inserted in the filter body 8, the closure body having an outwardly bulging surface which sealingly fits into the end of the secondary channel 14 when the cord 2 and the filter 6 are assembled together. It should be noted that also other closure means can be used instead of the closure body 18. I

FIG. 1 shows the cigarette in a partly smoked condition. The combustion zone 20 has approximately a shape as indicated by the dashed line 22 and leaves the usual ash body 24 behind. Upon smoking, air is introduced due to an underpressure produced at the suction mouth end of the cord 2, this introduced air being of two kinds: First, the usual primary air which enters outer areas 26 of the combustion zone 20 and passes the combustion zone 20 until it enters the still unburnt portion of the cord 2 via the innermost ranges 28 of the combustion zone and flows through that unburnt portion to the mouth end. This primary air serves to maintain the combustion in the combustion zone 20 and thus enriches correspondingly with the combustion products and forms the so-called main current smoke which after filtration in the unburnt portion of the tobacco cord 2 and possibly further filtration will be received by the smoker. At the time this primary air reaches the inner area 28 of the combustion zone 20, its oxygen content has already been considerably reduced so that in the inner area 28 a typical imcomplete combustion will take place which is characterized by a substantial oxygen deficit and is accompanied by a dry distillation of tobacco. In the cigarette illustrated, however, there is an additional intake of air from the outside through the secondary air channel 14. In the combustion zone 20 and in the ash body 24, the crosssection of the secondary air channel 14 remains approximately unchanged; merely the sealing effect of the layer 16 will be destroyed under the influence of the combustion process, whereby the secondary air which will be involved only to a small degree in the combustion taking place in the combustion zone 20 will pass the inner area 28 of the combustion zone and enter the cord 2 at a relatively high oxygen content and thus will ofier those inner areas of the combustion zone sufficient oxygen to make there the combustion more complete. In FIG. 1, primary air and secondary air are indicated by

arrows

30 and 32, respectively. It will be understood that it essential for the desired mode of operation that the sealing means separating the secondary air channel 14 from the cord 2 lose their sealing action under the influence of the combustion process. Further, it is essential that the secondary air channel 14 is sealed towards the suction end of the cord; this will prevent that the smoke prduced in the combustion zone will reach the mouth end of the cord directly, i.e., without having been filtered through the still unsmoked portion of the cord 2. The secondary air can reach the suction end of the cord only via the inner areas 28 of the combustion zone.

The embodiment illustrated in FIG. 2 corresponds to its largest part to the embodiment illustrated in FIG. 1. An important difference resides in the fact that the secondary air channel 14 comprises an ambient air connection 34 in the range of the channel end which is nearer to the mouth end of the cord. This ambient air connection 34 is separated from the suction path of the primary air. In the embodiment shown, the ambient air connection includes a transverse channel 36 which extends transversely of the axis of the cord 2 and is provided in a connector body 38 attached to the mouth end of the cord 2. The connector body 38 has a conically terminating end fitting 40 which upon assembling the cord 2 and the connector body 38 enters sealingly the end of the secondary air channel 14. The connecting sleeve 12 shown has openings 42 which are arranged over the outer ends of the transverse channel 36. Thus, due to the ambient air connection provided by the transverse channel 36, additional secondary air can enter the secondary air channel 14 in the manner indicated by the arrows 44 and can reach directly the inner ranges 28 of the combustion zone 20, as well as the secondary air 32 which comes from the forward end (the right end in FIG. 2) of the cigarette. In the connection between the end fitting 40 and the layer 16, a bonding agent, like gum arabic, can be additionally provided.

FIG. 3 illustrates the same cigarette as FIG. 2, but in an exploded longitudinal sectional view which is rotated by 90 relative to FIG. 2 and shows the components separated, with the connecting sleeve 12 being deleted. As can be readily seen, the connector body 38 forms a separate component in this embodiment, which is introduced between the cord 2 and the filter 6. FIG. 3 moreover shows the smoke channels 46 which are provided in the connector body 38 to allow passing of the smoke from the cord 2 to the filter 6. Furthermore, it is readily clear that the filter 6 may also be replaced with a simple mouthpiece or even completely dispensed with.

FIG. 4 shows an axial side view of the connector body 38 shown in FIG. 3. Furthermore, FIG. 4 indicates the section line III-III corresponding to FIG. 3. In the embodiment illustrated, a total of six smoke channels 46 are provided, the smoke channels being separated by narrow webs 48. In many cases, these webs can be omitted. The connector body 38 may consist of the most different materials, e.g., paper molding composition, plastic, and the like. A person skilled in the art will be easily able not only to select a suitable material but also to find other structural possiblities for communicating, in the manner described, the end of the secondary air channel 14 which is nearer to the suction end of the cord 2 with the ambient air via a connection which is separated from the suction path of the smoke.

FIG. is a side view of the left end of the cigarette shown in FIG. 4, as viewed in the direction of the arrow V of FIG. 2. FIG. 5 shows that preferably the opening 42 in the connecting sleeve 12 is dimensioned in the circumferential direction somewhat larger than the circumferential width of the outer ends of the transverse channel 36. This facilitates assembling the connecting sleeve 12 with the filter 6 and the cord 2. It is also possible to provide the connecting sleeve 12, in the axial range thereof which will be positioned over the outer ends of the transverse channel 36, with perforations extending over the whole circumference so that a continuous connection to the ambient air will be present at any angular position of the connecting sleeve 12 relative to the connector body 38.

FIG. 6 illustrates, in similar manner as FIG. 5, an embodiment wherein the ambient air connection formed by the transverse channel 36 comprises adjustable restriction means in the form of a sleeve 50 which is rotatably and/or displaceably arranged over that axial range of the cigarette where the outer ends of the ambient air connection are located. In the sleeve 50, passages 52, preferably wedge-shaped, are provided which in dependence on the position of the sleeve relative to the cigarette more or less restrict the connection to the ambient air. In this manner, the supply of secondary air can be influenced at will, whereby it will for instance be possible for the smoker to make the combustion more or less complete, as desired, and thus adjust or influence the taste of the smoke correspondingly. Preferably, a marking 51 and a scale 53 are provided. Furthermore, it is also possible to make the restriction means adjustable by means of a filter body which is rotatable relative to the cord 2.

FIG. 7 illustrates in a longitudinal sectional view corresponding to FIG. 2 a filter cigarette which principally corresponds to the cigarette shown in FIG. 2 but comprises a secondary air channel 114 which enlarges towards the mouth end of the cord 2. This embodiment shows very generally that it is possible to adapt the parameters, particularly the channel diameter, which are determining for the flow resistance of the secondary air channel to the desired supply of secondary air, and this even so that a predetermined, desired variation in the secondary air supply takes place as the smoking process proceeds. For example, in the embodiment shown in FIG. 7, the secondary air current aspirated through the transverse channel 36 will increase in relation to the primary air current 32 as the smoking of the cigarette proceeds. Thus, it can be taken into account that the smoke constituents which have precipitated in the unburnt portion of the tobacco cord 2 will more and more be again transferred into the smoke as the combustion proceeds and thus will cause an undesirable increase of the deleterious smoke constituents. The described increase of the secondary air supply will counteract that etTect.

In FIG. 7, it is further indicated that a supporting material 54 may be provided within the secondary air channel 14. By that supporting material, it can be safely prevented that the secondary air channel 14 will be deformed or damaged by the relatively high radial forces which possibly will occur upon application of the wrapper 4 to the cord 2. In order that the function of the secondary air channel 14 will only be disturbed as little as possible, care should be taken that the supporting material forms a flow resistance which is small as compared with the cord material. Further, it is desirable to alter the properties of the cigarette with regard to smoke taste and handling characteristics as little as possible; thus, it is advantageousto use smokable material as said supporting material, e.g., a tobacco which is of a coarser structure as compared with the cord 2, or a loose yet relatively stiff artificial material which for example may consist in known manner of tobacco dust and a bonding agent like cellulose acetate. This lastmentioned possibility is particularly advantageous because that supporting material will lose its coherence in a predetermined temperature range below the combustion temperature proper. Also other materials having similar properties have become known in connection with smokable articles, whereby there will be principally no difficulties in selecting a supporting material which loses its coherence in a predetermined temperature range between room temperature and the temperatures which exist during the smoking process in the combustion zone of the cord. Such material may advantageously also be used for the production of the sealing means which serve to seal the secondary air channel 14 towards the cord 2; these sealing means are illustrated in the figures generally in the form of a sealing layer 16. By using sealing means of that kind, it is possible to destroy the seal between the secondary air channel 14 and the cord 2 not only by the combustion of the layer 16 but even somewhat earlier, i.e., at a predetermined distance from the combustion zone. This apparently has the advantage that the secondary air supplied from the secondary air channel 14 can enter the inner ranges 28 of the combustion zone in a somewhat broader and more uniform flow pattern. Moreover, it can be ensured in this manner that a larger proportion of the secondary air supplied through the secondary air channel 14 is admixed as diluting and cooling air to the combustion and distillation products immediately after they have been produced.

The modes of operation described so far, particularly the mode of operation of the cigarette illustrated in FIG. 2, wherein a secondary air channel extends substantially in the axis of the cord, can be realized also with differently arranged secondary air channels. For example, it is possible that at least one secondary air channel is provided in the range of the outer circumference of the cord, and particularly it appears to be of advantage if the total cross-section of the cord is subdivided to a greater degree by distributing a plurality of secondary air channels across the cross-section and to thus obtain a more intense and more uniform supply of the secondary air across the whole combustion zone.

As an example for possibilities of this kind, FIGS. 8 and 9 illustrate schematically a filter cigarette in a longitudinal section and cross-section, respectively, wherein a plurality of secondary air channels 214 are provided in the outer circumferential range of the cord 2 and are distributed there over the circumference of the cord. The secondary air channels 214 extend longitudinally into deeper regions of the cord, whereby the secondary air can reach the innermore regions of the combustion zone in the desired manner. This mode of operation is readily apparent from FIGS. 8 and 9. Each of the total-of four secondary air channels 214 is sealed against the cord 2 in the same manner as the secondary air channel 14 of FIG. 2 by means of a layer 16. Furthermore, and again as in the embodiment illustrated in FIG. 2, each secondary air channel 214, in the region of its end which is nearer to the suction end of the cord 2, is provided with a connection to the ambient air, which connection is separated from the suction path of the smoke. These separate connections to the ambient air are produced upon assembling the cigarette by means of a connector body 138 which comprises, in the embodiment illustrated, a central smoke channel 46 and four end fittings 140 which are here degraded to recesses which enter into sealing engagement with the ends of the secondary air channels 214. As connections to the ambient air, transverse channels are provided in similar manner as in the embodiment according to FIG. 2. In FIG. 8, only two transverse channels 136 can be seen; here, these transverse channels simply consist of corresponding passages in the wrapper 4 and openings 42 in the connecting sleeve 12, the passages and openings being arranged in registry.

FIG. 10 shows an even simpler embodiment wherein the transverse channels or passages 236 are somewhat diplaced in the forward direction so that they are no longer covered by the connecting sleeve 12; in that case, the openings 42 in the connecting sleeve 12 are no longer necessary.

In the right half of FIG. 8, a further advantageous possibility of modification is indicated, this modification being characterized in that the outer secondary air channels 14 have connections to the ambient air distributed across their length, the connections taking the form of perforation openings 56. These perforation openings which generally facilitate the admittance of the secondary air are of particular advantage if a supporting material is provided within the secondary air channels 214 in the above-indicated manner.

Filling the secondary air channels with supporting material furthermore will be of particular advantage if the secondary air channel has a comparatively large cross-section. For example, this is the case if the embodiment illustrated in FIGS. 8 and 9 is further modified to the embodiment indicated in the cross-sectional view of FIG. 11, wherein a secondary air channel 314 surrounds the cord 2 in sleeve-like manner. In FIG. 1 l, a folded sheet-like supporting material 54 is indicated.

FIGS. 12 and 13 show schematically in a longitudinal sectional view and a cross-sectional view, respectively, a further embodiment wherein, like in the embodiment according to FIGS. 8 and 9, four outwardly arranged secondary air channels 414 are provided. Instead of the perforation openings, however, the idea is here utilized that outwardly arranged secondary air channels may be left open to the ambient air across at least part of their length. Accordingly, in the embodiment according to FIGS. 12 and 13, the secondary air channels are provided in the form of slots extending deeply to the cord 2. In this embodiment, the wrapper 4A of the cord and the layers 116 serving to seal the secondary air channels 414 against the cord 2 form a unitary wrapping body of relatively complicated cross-sectional shape. For example, a cigarette of that kind may be produced by first forming a shape-retaining cord 2 having the cross-section illustrated in FIG. 13 from tobacco dust and a bonding agent, and thereafter providing this cord on its outer surface with the sealing wrapping body 4A, 116. To this end, for example, a solution or suspension of cellulose, paper, cellulose acetate, starch or similar materials may be sprayed onto the outer surface of the preformed cord 2.

FIGS. 14 and 15 show schematically in a longitudinal sectional view and a cross-sectional view, respectively, an embodiment wherein in similar manner as in the modification according to FIG. 11 a secondary air channel 514 is provided which surrounds the cord 2 in sleeve-like manner. In that embodiment, the secondary air channel 514 has been made relatively large. In this case, it is advisable to fill the secondary air channel 514 with a smokable supporting material, e.g., tobacco. It is readily apparent that upon smoking also the supporting material will be consumed. If the flow resistance offered by the smokable supporting material provided within the secondary air channel is so large that the flow of secondary air through the transverse channels 36 and openings 42 provided in the vicinity of the suction end is too small, it will be advisable to make use of the perforations 56 illustrated in FIG. 8, as indicated in the right half of FIG. 14. Upon smoking, these perforations provide for a sufficiently large supply of secondary air to the inner regions 28 of the combustion zone 20. Due to the flow resistance of the smokable supporting material in the secondary air channel 514, then always those perforations 56 will preferably or even exclusively take over the supply of the secondary air, which momentarily lie in the vicinity of the inner region 28 of the combustion zone. Of course, the same effect as with the perforations 56 can be obtained if a pervious or porous material is used for the outer wrapping 4, e.g., porous cigarette paper. Furthermore, it is clear that the transverse channels 36 and openings 42 provided near the suction end can be omitted if the perforations 56 or corresponding measures are used. Then, a particularly simple structure of the cigarette illustrated in FIGS. 14 and 15 will result, which is characterized by a secondary air channel 514 which is filled with smokable material, which concentrically surrounds the main core 2, which is sealed towards the mouth end of the core but open towards the end facing the combustion zone, which is air-permeable in the outer wrapper 4, and which is sealed at the circumference engaging the main cord 2 by means of the layer 216 adapted to become progressively destroyed during the smoking process. Furthermore, in this particularly simple embodiment, only a very simple connector body 238 is needed, which easily can be provided as a com ponent of a filter or mouthpiece and substantially consists of a circular disk having a central smoke channel 146. A further interesting possibility consists in providing different smokable materials in the main cord 2 and in the secondary air channel 514. For instance, a comparatively light tobacco may be provided in the main cord, and a comparatively heavy tobacco in the secondary air channel 514.

The desired effects, particulary the improvement of the air supply to the interior regions of the combustion zone, may be further promoted by supplementary measures. One such measure consists in the provision of transversely extending additional channels in the cord, at least in a part of the cord portions in the vicinity of the secondary air channel. This results in finer subdivision of the combustion zone and improved supply of secondary air. FIG. 16 shows, in a view corresponding to FIG. 2, a central secondary air channel 614 in a cord 2. Additional channels 58 depend laterally from the secondary air channel 614 and are connected thereto. Accordingly, the sealing layer 216 extends also around these additional channels 58. As indicated in FIG. 16, a plurality of rows of additional channels 58 may be distributed around the circumference of the secondary air channel 14. In FIG. 16, the additional channels 58 are shown as being inclined, so as to extend from outwards to inwards towards the suction end of the cord. This serves for adaptation to the shape of the combustion zone as illustrated, for instance, in FIGS. 1, 2, 8 and 14. Generally, however, also radial additional channels may be used, and in some cases it will be even advantageous to use an inclination which is reverse to that shown in FIG. 16; this is particularly the case if the secondary air supply shall to a substantial degree serve to dilute and/or cool the smoke produced.

FIG. 17 illustrates in a view similar to FIG. 16 another embodiment wherein, however, the additional channels 158 are separated from the secondary air channel 714; obviously, this facilitates the manufacture of the device. The intended effect, however, will be substantially the same as in the embodiment according to FIG. 316 because the layer 16 sealing the secondary air channel 714 will lose its sealing function upon approach of the combustion zone 20, resulting in the production of a connection between the secondary air channel 714 and those additional channels 158 which are just reached by the combustion zone. In this embodiment, the additional channels 158 need not be sealed against the cord 2, i.e., they may have permeable walls. In the simplest case, such additional channels can be formed into the cord during production thereof. For example, correspondingly shaped needles or spikes may be pierced into the cord, and additionally a liquid or a solution of a bonding agent may be addedin order to prevent that the additional channels produced will close again after the tool has been withdrawn; the liquid or solution is selected so that the walls of the produced additional channels 158 rigidify in the desired manner without forming a continuous sealing layer. Instead of the radial additional channels 158 shown in FIG. 17, it will of course also be possible to use inclined additional channels, e.g., having similar inclinations as the additional channels according to FIG. 16, to obtainbetter adaptation to the shape of the combustion zone, indicated by the dashed line 22.

In several cases, it may be advisable to delimit and seal the secondary air channel against the cord of smokable material by means of a layer having particular mechanical strength. This is especially the case if a strongly compressed tobacco cord shall be used yet the provision of supporting material within the secondary air channel is to be avoided. In such cases, it may occur that the layer will not completely lose its sealing properties under the influence of the combustion zone. Thus, special measures appear to be advisable in order to ensure that in spite of such difiiculties the layer becomes sufficiently pervious in the region of the combustion zone. To that end, the layer bordering the secondary air channel may be provided with passages which are normally closed by closure means, with these closure means having the property that they will open the passages at least partly under the influence of the approaching combustion process, and will thus create the desired free cross-section for the transfer of secondary air from the secondary air channel into the cord of smokable material. FIGS. 18 and 19 illustrate in a purely schematic view and sectional view, respectively, a layer 416 bordering a secondary air channel, the layer consisting of a material which is capable of producing mechanical tension upon heating thereof and comprises flap-like cuts 60 which serve for passages as well as for closure means and open themselves due to the deformation of the layer caused upon approach of the combustion zone as the latter proceeds during the smoking process. In order to produce the necessary mechanical tension, the layer illustrated is composed of two plies 62, 64 of different thermal expansion characteristics. In the simplest case, the two plies consist of two different kinds of paper. In this manner, the result can be obtained as illustrated in the schematic sectional view of FIG. 19, that the flap-like areas defined by the cuts 60 will bulge inwardly in the vicinity of an approaching combustion zone 20 and thus will produce openings 66 of corresponding size. In the areas outside of the flaps defined by the cuts 60, the mechanical stresses produced by the approach of the combustion zone 20 will result only in slight deformations, if any, which will not appreciably disturb the desired function. It will be understood that the deformation described may be obtained also by providing a two-layered structure only in the regions where the flap-like cuts 60 are provided. In general, however, it will be more convenient to use a layer 416 which as a whole consists of two plies.

FIG. 20 illustrates another embodiment in a view corresponding to FIG. 19. In this embodiment, a single layer 516 is used to delimit and seal a secondary air channel with respect to a cord of smokable material. In the layer 516, passages 68 are preformed for the intake of secondary air. As a closure means for these passages, a closure material 70 is applied on the layer 516, the closure material being of a nature so as to lose its coherence in a predetermined temperature range between room temperature and the temperatures which exist in the combustion zone 20 upon smoking of the cord. This is indicated in FIG. 20 at the right passage 68. As is furthermore illustrated in that Figure, secure closing of the passage 68 can be obtained especially if the closure material is applied so that it fills the passages 68 substantially completely. A closure material of the kind described can also be additionally used in the embodiment according to FIGS. 18 and 19.

In the foregoing description, materials have been frequently mentioned which are to lose theirmechanical coherence or their sealing properties under the influence of the combustion process which upon smoking proceeds along the cord. Such materials are known in the art of the manufacture of cigarettes and cigarette paper. Particularly suited are cellulose products, e.g., ethyl cellulose (softening range approximately 90 to 140 C), cellulose acetate (softening range 60 to 130 C) polyethylene, sugar, starch glue, and other nonpoisonous material, e.g., also monosodiumphosphate or menthol.

Furthermore, it may be desirable to match the combustion velocities of the materials used. For example, it may be recommendable in the embodiments according to FIGS. 8, and 14, to provide for a greater combustion velocity of the materials used in the areas outside of the primary air suction path. For example, this will include the outer wrapper 4A and/or a supporting material which is possibly present in the

secondary air channel

114, 214, 514. In the art relating to smokable material, various possibilities of influencing the combustion velocity are commonly known; corresponding measures are also suitable for the devices as described in the present specification. Merely as an example, it should be mentioned that a known possibility of giving a material a desired increased combustion velocity consists in impregnating this material with an oxygen carrier, e.g., potassium nitrate.

Other andfurther modifications are possible without exceeding the scope of the invention.

I claim:

1. A smokable article particularly a cigarette, comprising a cord of smokable material, particularly tobacco, said cord having a combustion end and a mouth end, and a wrapper surrounding the cord of smokable material and being adapted to be progressively destroyed from its combustion end in correspondence with the progress of a smoking process while the smoke flows through said cord toward said suction end, means defining at least one secondary air channel extending lengthwise of the cord over at least part of the cord length, said secondary air channel being closed at the end which is nearer to the mouth end and open towards the other end of the cord, said air channel being formed of a sealing wall means which seals said air channel at least partly at its circumference against the cord of smokable material, said sealing wall means being of a material which progressively loses its sealing properties under the influence of the combustion as the latter proceeds along the cord during the smoking process, connection means providing communication between said secondary air channel and the ambient air adjacent the end of the secondary air channel which is nearer to the mouth end of the cord, the connection means including at least one smoke impervious channel extending from said secondary air channel to the surrounding ambient air whereby said connection means is separated from the suction path for the smoke.

2. The device according to claim 1, characterized in that the connection means to the ambient air is pro vided in the form of at least one transverse channel extending transversely of the axis of the cord.

3. A device in accordance with claim 1, characterized in that the ambient air connection means comprises adjustable restriction means.

4. A device in accordance with claim 3, characterized by the restriction means comprising a sleeve arranged over the outer end of the ambient air connection means, said sleeve being movable relative to the cord and comprising through-going passages adapted to be brought into registry with the outer end of the ambient air connection means.

5. A device in accordance with claim 1, characterized in that the ambient air connection means is provided in a connector body adjoining the mouth end of the cord, the ambient air connection means further comprising an end fitting adapted to enter into communication with the secondary air channel upon assembling the cord with the connector body.

6. The device according to claim 5, characterized in that the connector body comprises a smoke filter.

7. A device in accordance with claim 1, characterized in that a supporting material is provided within the secondary air channel, the supporting material being selected to offer a flow resistance which is small relative to that of the cord material.

8. The device according to claim 9, characterized in that the supporting material is a smokable material.

9. The device according to claim 8, characterized in that the supporting material is selected to lose its coherence in a predetermined temperature range between room temperature and the temperatures which exist in the combustion zone of the cord during the smoking process.

10. The device in accordance with claim 1, characterized by the sealing wall means comprising a layer of heat sensitive material which is combustible, the layer forming a border of the secondary air channel.

11. The device according to claim 10, characterized in that the layer bordering the secondary air channel is a sheet-like sleeve.

12. The device according to claim 11, characterized in that the sheet-like sleeve consists of smokable material.

13. A device according to claim 10, characterized in that the sealing wall means'includes passages, said passages being provided with closure means adapted to open said passages at least partly, under the influence of heat.

14. The device according to claim 13, characterized in that the layer bordering the secondary air channel consists of a material at least partly of two plies of different thermal expansion characteristics, and in that the passages and their closure means are provided in the form of flap-like cuts which open themselves due to deformation of the layer upon approach of the combustion zone as the latter proceeds along the cord in the course of the smoking process.

15. A device in accordance with claim 13, characterized by the closure means comprising a closure material selected to lose its coherence in a predetermined temperature range between room temperature and the temperatures existing in the combustion zone during.

smoking of the cord.

16. The device according to claim 15, characterized in that the closure material substantially fills the passages.

17. A device in accordance with claim 1, characterized in that transversely extending additional channels are provided in at least part of the cord zones adjacent the secondary air channel.

18. The device according to claim 17, characterized in that the additional channels extend laterally from the secondary air channel.

19. The device according to claim 18, characterized in that the additional channels are separated from the secondary air channel.

20. The device according to claim 18, characterized in that the additional channels have pervious walls.

21. A device in accordance with claim 1, characterized in that the diameter of the secondary air channel is enlarged toward the mouth end of the cord in correspondence with the desired supply of secondary air.

22. A device in accordance with claim 1, characterized in that said secondary channel extends substantially along the axis of the cord.

23. A device in accordance with claim 1, characterized in that a plurality of secondary channels are distributed throughout the cross-section of the cord.

24. A device in accordance with claim 1, characterized in that at least one secondary air channel is provided in the zone of the cord adjacent the outer circumference of the cord.

25. The device according to claim 24, characterized in that a plurality of secondary air channels are distributed in the zone of the cord adjacent the outer circumference of the cord.

26. A device in accordance with claim 24, characterized in that the outer secondary air channel comprises perforation openings, distributed over the length of the secondary air channel.

27. A device in accordance with claim 1, characterized by an annular secondary air channel surrounding the cord.

'UNITED STATES PATENT OFFICE y CERTIFICATE QF CORRECTION Patent No. 3,774,622 Deted November 27,; 1973] Inventor(s) Karl Heinz Steigerwald I It is certified that error appears inthe above-identified patent and that said Letters Patent are hereby corrected as shown below:

I Title page, insert the following:

"[30] FOREIGN APPLICATION PRIORITY DATA November 21, ]:970 Germany P 20.57 282. l-

Column 6, line 47, "imcomplete" to read -in'c omplete- 7 Column 7, line 5 "prducedfi to read --produced';

Column 10, line 18, "diplacedf' to read -displaced-w' I Column 12, line 17, "316" to read --l6-; and 'f'lglto read Signed and sealed this 23rd day of April 197k.

t SEAL) Attest:

129mm) 1: .FLET CHER JR Q MARSHALL DAM Atte sting Officer Commission's 1" of Patents FORM Po-wso (10-69) I uscoMM-oc bean-Pee I I "-5. GOVIIIIIINI PIIIIYIIUG OIIICI III 0-36-11

Claims

1. A smokable article particularly a cigarette, comprising a cord of smokable material, particularly tobacco, said cord having a combustion end and a mouth end, and a wrapper surrounding the cord of smokable material and being adapted to be progressively destroyed from its combustion end in correspondence with the progress of a smoking process while the smoke flows through said cord toward said suction end, means defining at least one secondary air channel extending lengthwise of the cord over at least part of the cord length, said secondary air channel being closed at the end which is nearer to the mouth end and open towards the other end of the cord, said air channel being formed of a sealing wall means which seals said air channel at least partly at its circumference against the cord of smokable material, said sealing wall means being of a material which progressively loses its sealing properties under the influence of the combustion as the latter proceeds along the cord during the smoking process, connection means providing communication between said secondary air channel and the ambient air adjacent the end of the secondary air channel which is nearer to the mouth end of He cord, the connection means including at least one smoke impervious channel extending from said secondary air channel to the surrounding ambient air whereby said connection means is separated from the suction path for the smoke.

2. The device according to claim 1, characterized in that the connection means to the ambient air is provided in the form of at least one transverse channel extending transversely of the axis of the cord.

13. A device according to claim 10, characterized in that the sealing wall means includes passages, said passages being provided with closure means adapted to open said passages at least partly, under the influence of heat.

15. A device in accordance with claim 13, characterized by the closure means comprising a closure material selected to lose its coherence in a predetermined temperature range between room temperature and the temperatures existing in the combustion zone during smoking of the cord.