U.S. patent number 3,774,622 [Application Number 05/199,136] was granted by the patent office on 1973-11-27 for device, particularly a cigarette, for smoking a cord of smokable material.
Invention is credited to Karl Heinz Steigerwald.
United States Patent |
3,774,622 |
Steigerwald |
November 27, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
DEVICE, PARTICULARLY A CIGARETTE, FOR SMOKING A CORD OF SMOKABLE
MATERIAL
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.
Inventors: |
Steigerwald; Karl Heinz
(Starnberg, DT) |
Family
ID: |
22736368 |
Appl.
No.: |
05/199,136 |
Filed: |
November 16, 1971 |
Current U.S.
Class: |
131/336; 131/193;
131/198.2; 131/339; 131/364 |
Current CPC
Class: |
A24C
1/00 (20130101) |
Current International
Class: |
A24C
1/00 (20060101); A24d 001/02 (); A24f 001/02 ();
A24f 005/04 () |
Field of
Search: |
;131/8R,8A,9,1A,10.5,4B,198R,198A,261B,195,193 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
1,905,273 |
|
Aug 1970 |
|
DT |
|
1,914,963 |
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Oct 1970 |
|
DT |
|
577,635 |
|
Jun 1958 |
|
IT |
|
Primary Examiner: Michell; Robert W.
Assistant Examiner: Pitrelli; John F.
Claims
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 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.
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.
Description
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
unburnt 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, taste-deteriorating 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
provide 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 unburnt 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 difficulties 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 differing 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
90.degree. 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 IX--IX 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. 11 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
XIII--XIII 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 XIX--XIX 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 14 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.
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 cross-section 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 offer 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.degree. 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. 5 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 effect.
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 advantageous to 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 last-mentioned 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 20 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. 11, 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 component 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 sub-division 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 added in 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
obtain better 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 difficulties
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 their mechanical 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.degree. to 140.degree.
C), cellulose acetate (softening range 60.degree. to 130.degree. C)
polyethylene, sugar, starch glue, and other non-poisonous 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, 10 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 and further modifications are possible without exceeding the
scope of the invention.
* * * * *