U.S. patent application number 12/526480 was filed with the patent office on 2010-09-09 for method and apparatus for the manufacture of smoking articles.
Invention is credited to Andrew McLellan.
Application Number | 20100224202 12/526480 |
Document ID | / |
Family ID | 37899236 |
Filed Date | 2010-09-09 |
United States Patent
Application |
20100224202 |
Kind Code |
A1 |
McLellan; Andrew |
September 9, 2010 |
Method and Apparatus for the Manufacture of Smoking Articles
Abstract
One embodiment of the invention provides a method and apparatus
for manufacturing a smoking article. The apparatus comprises a
conveyor (60) for a tobacco rod (65). The direction of conveyance
is parallel-to a central longitudinal axis of the tobacco rod (65).
The apparatus further comprises an applicator (72) for applying a
liquid additive to the tobacco rod (65) on the conveyor (60). The
applicator (72) is configured such that liquid additive received
into the tobacco rod (65) has a distribution in a cross-sectional
plane perpendicular to the central longitudinal axis of the tobacco
rod (65) that is substantially symmetrical about the central axis.
In one embodiment, the applicator (65) comprises a plurality of
dispensing heads (75A, 75B) disposed around the tobacco rod (65).
In another embodiment, the applicator (72) includes a plough (91)
for creating a furrow within the tobacco rod (65) and a dispensing
head (92) for dispensing additive into the furrow.
Inventors: |
McLellan; Andrew;
(Southampton, GB) |
Correspondence
Address: |
CHADBOURNE & PARKE LLP
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Family ID: |
37899236 |
Appl. No.: |
12/526480 |
Filed: |
January 18, 2008 |
PCT Filed: |
January 18, 2008 |
PCT NO: |
PCT/EP2008/050553 |
371 Date: |
March 3, 2010 |
Current U.S.
Class: |
131/284 |
Current CPC
Class: |
A24C 5/1892
20130101 |
Class at
Publication: |
131/284 |
International
Class: |
A24C 5/60 20060101
A24C005/60 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 13, 2007 |
GB |
0702769.1 |
Claims
1. Apparatus for manufacturing a smoking article comprising: a
conveyor for a tobacco rod, wherein the direction of conveyance is
parallel to a central longitudinal axis of the tobacco rod; and an
applicator for applying a liquid additive to the tobacco rod on the
conveyor, wherein said applicator is configured such that liquid
additive received into the tobacco rod has a distribution in a
cross-sectional plane perpendicular to the central longitudinal
axis of the tobacco rod that is substantially symmetrical about
said central longitudinal axis.
2. The apparatus of claim 1, wherein said applicator comprises a
plurality of dispersion heads for applying the liquid additive to
the tobacco rod.
3. The apparatus of claim 2, wherein said plurality of dispersion
heads has a configuration which is rotationally symmetric about the
central longitudinal axis of the tobacco rod.
4. The apparatus of claim 3, wherein said applicator comprises a
pair of dispersion heads disposed on opposite sides of the tobacco
rod.
5. The apparatus of claim 4, wherein said pair of dispersion heads
are horizontally disposed with respect to the tobacco rod.
6. The apparatus of any of claims 2 to 5, wherein each of said
heads penetrates into the tobacco rod.
7. The apparatus of claim 6, wherein the distance of head
penetration into the tobacco rod is small compared to the
cross-sectional dimensions of the tobacco rod.
8. The apparatus of any of claims 2 to 7, wherein each of said
heads is provided with its own reservoir of liquid additive for
application to the tobacco rod.
9. The apparatus of claim 1, wherein said applicator comprises: a
plough for forming a furrow in the tobacco rod downstream of the
plough; and a head for dispersing the liquid additive into the
tobacco rod, said head being positioned so as to be located within
the furrow of the tobacco rod.
10. The apparatus of claim 9, wherein the furrow formed by the
plough extends to approximately the central longitudinal axis of
the tobacco rod.
11. The apparatus of claim 9 or 10, wherein the plough is
static.
12. The apparatus of claim 9 or 10, wherein the plough is
rotary.
13. The apparatus of claim 12, wherein the plough has a linear
speed at its edge that is approximately equal to the speed of the
conveyed tobacco rod.
14. The apparatus of any of claims 9 to 13, wherein said head is
positioned adjacent the base of the furrow to disperse the liquid
additive.
15. The apparatus of any of claims 9 to 14, wherein said plough and
said head are both positioned to enter the tobacco rod from
above.
16. The apparatus of any of claims 9 to 15, wherein the dispensed
additive is limited to a central region of the tobacco rod, and
wherein the radius of said central region is small compared to the
radius of the tobacco rod.
17. Apparatus for manufacturing a smoking article comprising: a
conveyor for a tobacco rod, wherein the direction of conveyance is
parallel to a central longitudinal axis of the tobacco rod; and an
applicator for applying a liquid additive to the tobacco rod on the
conveyor, wherein said applicator has a plurality of heads for
simultaneously dispersing the liquid additive into the tobacco
rod.
18. Apparatus for manufacturing a smoking article comprising: a
conveyor for a tobacco rod, wherein the direction of conveyance is
parallel to a central longitudinal axis of the tobacco rod; and an
applicator for applying a liquid additive to the tobacco rod on the
conveyor, wherein said applicator comprises a plough for forming a
furrow in the tobacco rod downstream of the plough, and a head for
dispersing the liquid additive into the tobacco rod, said head
being positioned so as to be located within the furrow of the
tobacco rod.
19. The apparatus of any of claims 2 to 18, wherein each head of
the applicator is configured to retract when the conveyor
stops.
20. The apparatus of any preceding claim, wherein said conveyor
comprises a suction belt.
21. The apparatus of any preceding claim, wherein said liquid
additive comprises menthol.
22. A method for manufacturing a smoking article comprising:
conveying a tobacco rod in a direction parallel to a central
longitudinal axis of the tobacco rod; and applying a liquid
additive to the conveyed tobacco rod such that the liquid additive
received into the tobacco rod has a distribution in a
cross-sectional plane perpendicular to the central longitudinal
axis of the tobacco rod that is substantially symmetrical about
said central axis.
23. The method of claim 22, wherein the liquid additive is applied
to the tobacco rod by a plurality of dispersion heads.
24. The method of claim 23, wherein said plurality of dispersion
heads has a configuration which is rotationally symmetric about the
central longitudinal axis of the tobacco rod.
25. The method of claim 24, wherein said plurality of dispersion
heads comprises a pair of dispersion heads disposed on opposite
sides of the tobacco rod.
26. The method of claim 25, wherein said pair of dispersion heads
are horizontally disposed with respect to the tobacco rod.
27. The method of any of claims 23 to 26, wherein each of said
heads penetrates into the tobacco rod.
28. The method of claim 27, wherein the distance of head
penetration into the tobacco rod is small compared to the
cross-sectional dimensions of the tobacco rod.
29. The method of any of claims 23 to 28, wherein each of said
heads is provided with its own reservoir of liquid additive for
application to the tobacco rod.
30. The method of claim 22, wherein said method further comprises:
forming a furrow in the tobacco rod with a plough, said furrow
being formed downstream of the plough; and dispersing the liquid
additive into the tobacco rod with a head positioned so as to be
located within the furrow of the tobacco rod.
31. The method of claim 30, wherein the furrow formed by the plough
extends to approximately the central longitudinal axis of the
tobacco rod.
32. The method of claim 30 or 31, wherein the plough is static.
33. The method of claim 30 or 31, wherein the plough is rotary.
34. The method of claim 33, wherein the plough has a linear speed
at its edge that is approximately equal to the speed of the
conveyed tobacco rod.
35. The method of any of claims 30 to 34, further comprising
positioning the head adjacent the base of the furrow to disperse
the liquid additive.
36. The method of any of claims 30 to 35, further comprising
positioning the plough and the head to enter the tobacco rod from
above.
37. The method of any of claims 30 to 36, wherein the dispensed
additive is limited to a central region of the tobacco rod, and
wherein the radius of said central region is small compared to the
radius of the tobacco rod.
38. A method for manufacturing a smoking article comprising:
conveying a tobacco rod in a direction parallel to a central
longitudinal axis of the tobacco rod; and applying a liquid
additive with an applicator to the conveyed tobacco rod, wherein
said applicator has a plurality of heads for simultaneously
dispersing the liquid additive into the tobacco rod.
39. A method for manufacturing a smoking article comprising:
conveying a tobacco rod in a direction parallel to a central
longitudinal axis of the tobacco rod; and applying a liquid
additive with an applicator to the conveyed tobacco rod by forming
a furrow in the tobacco rod with a plough, wherein said furrow is
formed downstream of the plough, and dispersing the liquid additive
from a head into the tobacco rod, said head being positioned so as
to be located within the furrow of the tobacco rod.
40. The method of any of claims 23 to 39, further comprising
retracting each head of the applicator when the conveyor stops.
41. The method of any of claims 22 to 40, wherein said conveying is
performed by a suction belt.
42. The method of any of claims 22 to 41, wherein said liquid
additive comprises menthol.
43. A smoking article produced by the method of any of claims 22 to
42.
44. A smoking article produced by the apparatus of any of claims 1
to 21.
45. Apparatus for manufacturing a smoking article substantially as
described herein with reference to the accompanying drawings.
46. A method for manufacturing a smoking article substantially as
described herein with reference to the accompanying drawings.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to smoking articles such as
cigarettes and to a method and apparatus for the manufacture
thereof.
BACKGROUND OF THE INVENTION
[0002] It is known to apply an additive to a cigarette or other
smoking article. The additive can serve various purposes, for
example, it may comprise a flavourant (e.g. menthol), an adhesive
(e.g. starch), or some substance for controlling the burn
characteristics of a cigarette.
[0003] C.B. Kaymich & Co of Sheffield, United Kingdom (see
www.kaymich.co.uk) manufacture various systems for the application
of additives to the different parts of a cigarette, such as the
filter, the wrapping paper and the tobacco. The Kaymich CSS1000
system can be used to apply adhesive to cigarette paper. WO
2006/010895 (to Kaymich) discloses one method of applying an
additive to the filter material of a cigarette. The Kaymich UFA1000
system is designed for the application of a flavourant, such as
menthol, to various components of a cigarette, including the
cigarette paper and the tobacco stream (rod).
[0004] One known system for applying a flavourant to a tobacco rod
includes an atomising applicator head that is positioned adjacent
the passing tobacco rod. The flavourant, in either solvent or
undiluted form, is dispersed from the applicator head at a steady
rate onto the passing tobacco rod. The applicator head retracts
during a machine stop to prevent excess flavourant being applied to
a particular location on the tobacco rod.
[0005] The amount of flavouring or other additive that is applied
to a tobacco rod is known as the loading. It has been found that in
practice there is limit to the maximum loading for flavourants such
as menthol in order to avoid spotting. Thus if the loading is too
high, excess menthol may accumulate and form (yellow) spots on the
paper wrapping of the cigarette. Alternatively (or additionally),
an excess of flavouring or other additive may produce (brown) spots
by leaching substances such as tannins from the tobacco onto the
paper wrapping.
[0006] The presence of spotting unsightly, and significantly
degrades the appearance of the product. The maximum safe loading of
menthol through the above-described application method to avoid
spotting has been found to be approximately 5-6 mg per cigarette,
although this is somewhat dependent on factors such as humidity and
temperature (increased humidity and/or temperature may increase the
tendency to spotting).
[0007] A general trend in the tobacco industry over recent years
has been to increase the amount of menthol in cigarettes. Since the
maximum loading that can be applied to the tobacco rod itself is
limited by spotting, one option is to increase the amount of
menthol per cigarette by applying additional flavouring to the
components of the cigarette other than the tobacco rod--i.e. the
filter and/or the cigarette paper. However, this can lead to other
disadvantages. For example, it is known to include mentholated foil
wraps in cigarette packaging. It takes about 14-21 days for the
menthol to migrate from such foils into the tobacco and/or the
filter. This delay can make it more difficult to manage stock
control and manufacturing levels.
[0008] Another option is to apply menthol to bulk tobacco, in other
words before formation of the tobacco rod. However, the application
of flavourants to bulk tobacco requires bulk processing, and is
therefore not always cost-effective, especially for short
production runs. Furthermore, bulk application of flavourant before
the tobacco enters the manufacturing apparatus results in
contamination by flavourant of the whole production line. This may
cause problems in certain machinery, and also requires considerable
time and resources to clean the production line if it is desired to
switch to another flavourant (or to no flavourant).
SUMMARY OF THE INVENTION
[0009] One embodiment of the invention provides apparatus for
manufacturing a smoking article. The apparatus includes a conveyor
for a tobacco rod, wherein the direction of conveyance is parallel
to a central longitudinal axis of the tobacco rod. The apparatus
further includes an applicator for applying a liquid additive, such
as menthol, to the tobacco rod on the conveyor. The applicator is
configured such that liquid additive received into the tobacco rod
has a distribution in a cross-sectional plane perpendicular to the
central longitudinal axis of the tobacco rod that is substantially
symmetrical about the central longitudinal axis.
[0010] Known applicators involve dispersing an additive into a
tobacco rod from one side. This leads to an asymmetric distribution
of additive within the tobacco rod. In contrast, providing a
symmetric distribution of additive within the tobacco rod improves
uniformity, and so helps to avoid peaks of additive concentration
that might lead to spotting. This therefore allows a higher loading
of additive to be achieved in the tobacco rod than can be obtained
with known applicators (without increasing the risk of spotting).
This higher loading in the tobacco rod then avoids having to apply
(extra) additive to the filter or packaging, which would increase
the cost and complexity of the manufacturing process.
[0011] In one embodiment, the applicator comprises a plurality of
dispersion heads for applying the liquid additive to the tobacco
rod. The dispersion heads may have a configuration which is
rotationally symmetric about the central longitudinal axis of the
tobacco rod to provide the desired symmetrical distribution of
additive in the tobacco rod. For example, a pair of dispersion
heads may be disposed horizontally on opposite sides of the tobacco
rod. Other embodiments may have a different number and/or
configuration of heads.
[0012] In one embodiment, the applicator comprises a plough for
forming a furrow in the tobacco rod downstream of the plough and a
head for dispersing the liquid additive into the tobacco rod. The
head is positioned so that in operation it is located within the
furrow of the tobacco rod, which may extend to approximately the
central longitudinal axis of the tobacco rod. This configuration
allows the head to disperse liquid deeper into the tobacco rod, and
so helps to reduce the possibility of spotting on the surface of
the tobacco rod. Furthermore, dispersing from the centre of the
tobacco rod can help to produce a more uniform distribution of
liquid within the tobacco rod.
[0013] In one embodiment, the plough is static. Such a plough
generally has a pointed head directed upstream to face the oncoming
tobacco rod. This allows the plough to cleave into the oncoming
tobacco stream, thereby opening up the furrow without completely
disrupting the tobacco rod. In another embodiment, the plough may
be rotary, for example, some form of cutting wheel that extends
into the tobacco rod, where the rotation axis of the cutting wheel
is perpendicular to the longitudinal axis of the tobacco rod. The
cutting wheel may rotate so that it runs at substantially the same
linear speed as the tobacco rod.
[0014] In one embodiment, the plough and the head are both
positioned to enter the tobacco rod from above. However, other
geometries are also possible, for example, the plough and head
might alternatively enter the tobacco rod from below or from the
side.
[0015] In one embodiment, each head of the applicator is configured
to retract from the tobacco rod when the conveyor stops. This helps
to reduce the risk of excess additive being dispersed into a fixed
location of a stationary tobacco rod.
[0016] Another embodiment of the invention provides apparatus for
manufacturing a smoking article comprising: a conveyor for a
tobacco rod, wherein the direction of conveyance is parallel to a
central longitudinal axis of the tobacco rod; and an applicator for
applying a liquid additive to the tobacco rod on the conveyor. The
applicator has a plurality of heads for simultaneously dispersing
the liquid additive into the tobacco rod. It will be appreciated
that such an apparatus may benefit from the same particular
features as described in relation to the previous embodiments.
[0017] Another embodiment of the invention provides apparatus for
manufacturing a smoking article comprising: a conveyor for a
tobacco rod, wherein the direction of conveyance is parallel to a
central longitudinal axis of the tobacco rod; and an applicator for
applying a liquid additive to the tobacco rod on the conveyor. The
applicator comprises a plough for forming a furrow in the tobacco
rod downstream of the plough and a head for dispersing the liquid
additive into the tobacco rod. The head is positioned so as to be
located within the furrow of the tobacco rod. Again, it will be
appreciated that such an apparatus may benefit from the same
particular features as described in relation to the previous
embodiments.
[0018] Another embodiment of the invention provides a method for
manufacturing a smoking article comprising: conveying a tobacco rod
in a direction parallel to a central longitudinal axis of the
tobacco rod; and applying a liquid additive to the conveyed tobacco
rod such that the liquid additive received into the tobacco rod has
a distribution in a cross-sectional plane perpendicular to the
central longitudinal axis of the tobacco rod that is substantially
symmetrical about said central axis.
[0019] Another embodiment of the invention provides a method for
manufacturing a smoking article comprising: conveying a tobacco rod
in a direction parallel to a central longitudinal axis of the
tobacco rod; and applying a liquid additive with an applicator to
the conveyed tobacco rod, wherein the applicator has a plurality of
heads for simultaneously dispersing the liquid additive into the
tobacco rod.
[0020] Another embodiment of the invention provides a method for
manufacturing a smoking article comprising: conveying a tobacco rod
in a direction parallel to a central longitudinal axis of the
tobacco rod; and applying a liquid additive with an applicator to
the conveyed tobacco rod by forming a furrow in the tobacco rod
with a plough, wherein the furrow is formed downstream of the
plough, and dispersing the liquid additive from a head into the
tobacco rod. The head being positioned so as to be located within
the furrow of the tobacco rod.
[0021] It will be appreciated that the various method embodiments
of the invention may benefit from the same particular features as
the apparatus embodiments of the invention.
[0022] Another embodiment of the invention provides a smoking
article, such as a cigarette, cigar or cigarillo, as produced by
the method or apparatus described above.
[0023] The approach described herein achieves a higher loading of
flavourant or other additive in tobacco, thereby avoiding adding
flavourant to the filter and/or the packaging, and so saves time
and resources. This allows easier processing and can help to
improve quality (because it involves flavourant at only one stage
of the processing), as well as providing easier cleaning and
smaller volumes to be processed, leading to reduced waste.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Various embodiments of the invention will now be described
in detail by way of example only with reference to the following
drawings:
[0025] FIG. 1 is a schematic plan view of cigarette manufacturing
apparatus in accordance with one embodiment of the invention.
[0026] FIG. 2 is a schematic cross-section through a portion of the
manufacturing apparatus of FIG. 1 in accordance with one embodiment
of the invention.
[0027] FIGS. 3A-3C are schematic illustrations of possible head
positions for the manufacturing apparatus of FIG. 1 in accordance
with various embodiments of the invention.
[0028] FIG. 4 is a schematic plan view of cigarette manufacturing
apparatus in accordance with another embodiment of the
invention.
[0029] FIG. 5 is a schematic view illustrating the operation of the
cigarette manufacturing apparatus of FIG. 4 in accordance with one
embodiment of the invention.
[0030] FIGS. 6A-6D are schematic cross-sections through FIG. 5 in
accordance with one embodiment of the invention.
DETAILED DESCRIPTION
[0031] FIG. 1 is a schematic plan view (not to scale) of cigarette
manufacturing apparatus in accordance with one embodiment of the
invention. The apparatus includes a hopper 40 of bulk tobacco which
feeds tobacco into a tobacco rod (or stream) 65 formed by suction
belt 60. The general flow of tobacco within stream 65, as it is
conveyed by the vacuum of the suction belt 60, is in the direction
indicated by arrow A in FIG. 1.
[0032] The tobacco rod 65 is trimmed by a pair of ecreteur disks
70. Accordingly, the tobacco rod 65 leaving the ecreteur disks is
slightly smaller than the tobacco rod entering the ecreteur disks.
After passing through the ecreteur disks 70, the tobacco rod 65
arrives at a flavourant adder 72. The flavourant adder 72 may be
located within the suction chamber (not shown) of a conventional
cigarette manufacturing system. The tobacco rod 65, including the
added flavourant, such as menthol, then progresses into the
garniture area 80, where the tobacco rod is cut into portions and
associated with filters for subsequent packaging.
[0033] Note that by positioning the flavourant adder at this
location on the production line, the upstream apparatus (such as
ecreteur disks 70) avoids contamination by the flavourant. This
makes it easier to switch the production line to making cigarettes
having a different added flavour (or having no added flavour),
since relatively little apparatus on the production line needs to
be cleaned and/or adjusted to effect such a change. In addition,
applying the flavourant at a relatively late stage in the
production reduces wastage (compared to applying the flavourant to
bulk tobacco, for example, since a certain proportion of the bulk
tobacco is expended in the general manufacturing process, and never
reaches the final product).
[0034] It can be seen that in contrast to current systems for
adding flavourant, flavourant adder 72 includes a pair of heads
75A, 75B disposed on either side of tobacco rod 65. In one
embodiment, the two heads 75A, 75B are substantially conical (or
needle-like) in shape.
[0035] The two heads 75A, 75B are used to atomise the flavourant,
which is sprayed into the tobacco rod from both of the heads. The
two heads 75A and 75B are fed the flavourant in fluid form from a
reservoir (not shown in FIG. 1). In one embodiment, each head is
provided with its own reservoir (which then generally needs
separate replenishment). Alternatively both heads may share a
common reservoir for the flavourant fluid. In one embodiment, the
two heads may be heated slightly to assist with dispersion of the
flavourant (such heating may or may not be employed, depending on
the properties of the particular flavourant being used).
[0036] The amount of flavourant ejected from the heads is
controlled in conjunction with the speed of conveyor 60. In other
words, if the conveyor is going fast, more spray is ejected from
heads 75A, 75B, while if the conveyor is going more slowly, less
spray is ejected from heads 75A, 75B. This facility helps to supply
a constant amount of menthol to a given weight or length of the
tobacco rod 65. In one embodiment, heads 75A and 75B are
retractable, and can be withdrawn from the tobacco rod 65 if the
tobacco rod 65 stops moving--e.g. because the suction belt is
switched off.
[0037] In the embodiment of FIG. 1, each of the heads 75A, 75B is
inserted slightly into the tobacco rod 65. This then allows the
atomised spray to be dispersed directly into the tobacco itself.
The insertion distance is substantially less than the radius of
tobacco rod 65 (to prevent splitting or other disruption of the
tobacco rod 65).
[0038] FIG. 2 is a schematic vertical cross-section (not to scale)
of a part of the apparatus of FIG. 1, in accordance with one
embodiment of the invention. This cross-section is perpendicular to
the longitudinal axis of tobacco rod 65; in other words, the plane
of FIG. 2 is orthogonal to arrow A in FIG. 1. In FIG. 2, the
tobacco rod 65 is shown as having an approximately square
cross-section, but in other embodiments this cross-section may be
round, rectangular, elliptical, or any other appropriate shape,
depending upon how tobacco rod is formed and trimmed.
[0039] Also shown in FIG. 2 are the two heads 75A, 75B of
flavourant adder 72. These two heads are gravity-fed with
flavourant to be added to tobacco rod 65 from reservoir 120. In
some embodiments, the feed to the heads may be power-assisted (by
some suitable form of pump), and/or each head may be provided with
its own, separate reservoir, as noted above.
[0040] The approximate dispersion of the flavourant from head 75A
into tobacco rod 65 is depicted in FIG. 2 by shaded area 110A.
Likewise, the approximate dispersion of the flavourant from head
75B into tobacco rod 65 is depicted in FIG. 2 by shaded area 110B.
Note that the dispersion of the flavourant is substantially
symmetrical about the central longitudinal axis of tobacco rod 65,
as marked by a "+" with reference numeral 115 in FIG. 2. This in
turn reflects the fact that heads 75A, 75B are likewise
symmetrically disposed about the central longitudinal axis of
tobacco rod 65.
[0041] The head configuration of FIG. 2 allows for a more uniform
dispersion of flavourant through the cross-section of tobacco rod
65 (compared to known machines which use a single head for adding
flavourant to tobacco rod 65). This in turn helps to permit a
higher concentration of flavourant, such as menthol, to be provided
within tobacco rod 65 without increasing the risk of spotting. This
is because spotting is generally most likely at regions of greatest
concentration. However by providing a more uniform (and more
symmetrical) distribution of flavourant within the tobacco rod 65
(compared to known machines), the total loading of flavourant
within tobacco rod 65 can be increased without raising the maximum
concentration at any one point, thereby helping to avoid any
increased risk of spotting.
[0042] In the embodiment of FIG. 2, the two heads 75A and 75B are
disposed horizontally about the central longitudinal axis of
tobacco rod 65. Note that in this embodiment, the effect of gravity
on the flavourant dispersion region 110 is the same for both heads
75A, 75B, which can assist with uniformity and symmetry. In other
embodiments, a somewhat different configuration of heads might be
used. For example, the heads might be offset above or below the
central longitudinal axis of tobacco rod 65, or rotated around from
the horizontal--e.g. one head pointing upwards from below the
central longitudinal axis of tobacco rod 65 and one head pointing
downwards from above the central longitudinal axis of tobacco rod
65.
[0043] In other embodiments, there may be more than two heads 75
for injecting flavourant into tobacco rod 65. FIGS. 3A-3C show a
variety of such embodiments. In the embodiment of FIG. 3A, the two
horizontally directed heads 75A, 75B from the embodiment of FIG. 2
are supplemented by a third, downwardly directed head 75C, located
above tobacco rod 65. In the embodiment of FIG. 3B, there are again
three heads, but in this embodiment the two heads 75A and 75B on
the sides of the tobacco rod 65 are shifted downwards and rotated
into a slightly upwards facing direction. This leads to a
configuration which has rotational symmetry (of order 3) about the
central longitudinal axis of the tobacco rod. In the embodiment of
FIG. 3C the two horizontally directed heads 75A, 75B from the
embodiment of FIG. 2 are supplemented by a third, downwardly
directed head 75C, located above tobacco rod 65, and a fourth,
upwardly directed head 75D, located below tobacco rod 65. The
configuration of FIG. 3C has rotational symmetry (of order 4) about
the central longitudinal axis of the tobacco rod. The skilled
person will be aware of other possible configurations for heads 75,
further to those shown in FIGS. 3A-3C.
[0044] In some embodiments, different heads may be used to disperse
different additives into the tobacco rod 65. For example, heads 75A
and 7513 in the configuration of FIG. 3C may disperse one additive
into tobacco rod 65, while heads 75C and 75D simultaneously
disperse a second additive into the tobacco rod. In some
situations, the multiple additives may interact or combine with one
another. For example, one additive may be a binder to help a second
additive, such as a flavourant, adhere to the tobacco.
[0045] Adding extra heads 75 to the flavourant adder 72 (compared
to the pair of heads shown in the embodiment of FIG. 2) can
increase the uniformity and symmetry of the distribution of
flavourant as provided within tobacco rod 65. This in turn may
allow a higher loading of flavourant without (significantly)
increasing the risk of spotting. On the other hand, adding extra
heads 75 to the flavourant adder 72 also increases the complexity
and cost of the flavourant adder 72.
[0046] FIG. 4 illustrates a manufacturing apparatus for smoking
articles in accordance with another embodiment of the invention.
The components of this embodiment are generally the same as those
of FIG. 1, except in relation to flavourant adder 72. Thus in the
embodiment of FIG. 4, flavourant adder comprises a single atomising
head 92 for dispersing liquid additive within tobacco rod 65. The
head 92 may be substantially the same as heads 75A and 7513
described in relation to the embodiment of FIG. 1. In other
embodiments, head 92 may comprise a hypodermic needle (rather than
an atomising spray). Head 92 may be connected to an appropriate
reservoir of the liquid additive (not shown in FIG. 4).
[0047] The flavourant adder of FIG. 4 also includes a plough 91
that is located upstream of the head 92. Note that in some
embodiments, plough 91 and head 92 may be formed as a single unit.
The plough 91 causes a furrow to open in the tobacco stream 65 that
goes past the plough. Head 92 is located in the furrow (slipstream)
created by plough 91.
[0048] FIG. 5 presents a further schematic illustration of the
action of plough 91 and head 92 in accordance with one embodiment
of the invention. FIG. 5 depicts tobacco rod 65 travelling in the
direction of arrow A past plough 91. The plough opens up a furrow
or gap 210 in the tobacco rod, which extends downstream of the
plough. Note that furrow 210 gradually narrows as it progresses
further downstream from the plough, due to the natural dynamics and
pressure within tobacco rod 65. Eventually the furrow closes (at
the point indicated as 211 in FIG. 5), whereupon tobacco stream 65
has returned substantially to its original geometry.
[0049] The head 92 is located within the furrow 210 created by the
plough. As previously described in relation to the embodiment of
FIG. 1, head 92 (and also potentially plough 91) may be configured
to retract from tobacco stream 65 if the flow of tobacco by
conveyor 60 stops.
[0050] The arrangement of FIG. 5 allows the head to penetrate more
deeply into the tobacco stream 65 than for the embodiment of FIG.
1. This in turn allows the head 92 to disperse liquid into the
tobacco stream from close to the centre of the tobacco stream.
Accordingly, a more uniform (rotationally symmetric) distribution
of liquid within tobacco rod 65 can be obtained. This allows the
loading of additive within the tobacco rod to be increased without
raising the risk of spotting. Furthermore, because the additive is
injected nearer to the centre of the tobacco rod, any excess
concentration of additive that does occur will tend to be contained
within the body of the tobacco rod, rather than migrating to the
surface (where it could then manifest itself as visible
spotting).
[0051] FIGS. 6A-6D are schematic cross-sections through tobacco rod
65, corresponding to arrows C1-C4 respectively from FIG. 5, in
accordance with one embodiment of the invention. In other words, a
given portion of tobacco rod 65 passes through the stages of FIGS.
6A, 6B, 6C and then 6D in succession as it travels along conveyor
60. Note that in FIGS. 6A-6D, tobacco rod 65 is assumed to have a
substantially rectangular cross-section, although other embodiments
may utilise a different cross-section for the tobacco rod--e.g.
circular, ellipse, etc.
[0052] FIG. 6A illustrates an upstream portion of the plough 91 in
accordance with one embodiment of the invention. This portion of
the plough is relatively narrow, and also relatively shallow, so
that it can cleave open the tobacco rod 65 to form furrow 210. FIG.
6B illustrates a more downstream portion of the plough 91 in
accordance with one embodiment of the invention. This portion of
the plough 91 is both wider and longer than in FIG. 6A, thereby
increasing the width and depth of furrow 210. This streamlined
configuration of plough 91, small at the front, larger at the rear,
provides minimal disruption to the tobacco stream 65 flowing past
the plough (other than to open furrow 210). Note that the deepest
portion of furrow 210, as shown in FIG. 6B, extends approximately
to the centre of tobacco rod 65.
[0053] FIG. 6C illustrates the operation of head 92 within furrow
210 in accordance with one embodiment of the invention. Since the
general tendency of furrow 210 is to close up as the tobacco
progresses downstream of plough 91, furrow 210 in FIG. 6C is
narrower than shown in FIG. 6B (but wider than shown in FIG. 6A).
Nevertheless, furrow 210 in FIG. 6C is wide and deep enough to
accommodate head 92, which is therefore able to disperse liquid
from reservoir 120 internally into tobacco rod 65.
[0054] In one embodiment, head 92 disperses liquid into tobacco rod
65 from the tip of head 92, which is positioned at or close to the
longitudinal central axis of tobacco rod 65. This leads to an
approximate distribution of additive 220 within the tobacco rod 65
as shown in FIG. 6C. It can be seen that the additive is
concentrated within the central portion of tobacco rod 65, away
from the surface of the tobacco rod, due to the central location of
the point of injection from head 92. This helps to minimise
spotting, which arises from excess additive adjacent to the surface
of cigarettes.
[0055] The central location of the internal point of injection from
head 92 also allows a more uniform (or rotationally symmetric)
distribution of additive within tobacco rod 65. This again helps to
achieve an increased loading of additive within the tobacco rod
(compared to known machines which inject additive from one side),
since there is less risk of concentrations of additive forming in
particular areas, which might then lead to spotting.
[0056] In some embodiments, head 92 itself penetrates slightly into
the tobacco rod (i.e. beyond the bottom of furrow 210), analogous
to the situation depicted in FIG. 2. This penetration by head 92
can assist with dispersal of the additive into the tobacco (and
also prevent dispersal of the additive into furrow 210, which might
then migrate relatively easily to the surface of tobacco rod
65).
[0057] The angle of dispersion from head 92 is fairly wide
(compared to the narrower dispersion from heads 75A and 75B shown
in FIG. 2). For example, the dispersion from heads 75A, 75B occurs
into a cone having a (half)-angle approximately in the range 20 and
65 degrees, e.g. approximately 30 degrees. In contrast, the conical
(half)-angle of dispersion from head 92 is greater than 120
degrees, and may approach 180 degrees (depending on the size and
geometry of the head 92 itself and furrow 210). The angle and also
shape of dispersion from heads 75A, 75B and 92 can be controlled by
appropriate head design. (The dispersion shape may not necessarily
be conical, bearing in mind the longitudinal motion of the tobacco
rod past the head).
[0058] In some embodiments, the angle of dispersion from head 92
may be relatively small, for example with a conical half-angle of
50 degrees or less, 30 degrees or less, or 15 degrees or less. A
relatively narrow (constrained) output from head 92 is particularly
suitable if it is desired to confine the additive to substantially
the centre of the tobacco rod. In this case, the radius of the
portion of the tobacco rod containing additive is small compared to
the radius of the tobacco rod, for example perhaps only 50%, 30% or
15% of the radius of the latter. This confined arrangement, with
the flavourant bead located substantially along the central
longitudinal axis of the tobacco rod, maintains a significant gap
between the flavourant and the outer surface of the cigarette, and
so helps to protect against spotting.
[0059] FIG. 6D illustrates the tobacco rod downstream of head 92.
In this position furrow 210 is starting to close up, due to natural
motion within the tobacco rod as it is drawn along conveyor 60. In
general, this closure of furrow 210 enhances the uniformity and
symmetry of the additive distribution 220 within tobacco rod
65.
[0060] In the particular embodiment of FIG. 4, the plough 91 and
head 92 are shown entering the tobacco rod from the side. However,
the plough 91 and head 92 may also enter the tobacco rod from the
bottom or from the top (or from any other angle). Entry from the
top may cause less disruption to the tobacco rod (apart from the
creation of furrow 210).
[0061] Although FIGS. 4-6 illustrate the use of a static plough, in
other embodiments, a rotary plough might be used. The axis of
rotation of such a plough is substantially perpendicular to the
flow direction of tobacco rod 65. In this case, the operation of
the plough could be considered as somewhat analogous to a circular
saw cutting into the tobacco rod 65. In one particular embodiment,
the rotation speed of the plough cutting wheel is synchronised with
the movement of the tobacco rod, so that the linear speed
(velocity) of the edge of the wheel is the same as or similar to
the speed of movement of the tobacco stream. This then provides
comparatively little relative movement between the wheel and the
tobacco rod at the point of cutting, which can help to avoid damage
to the tobacco stream. In general, the configuration and operation
of plough 91 for a given tobacco stream can be arranged to provide
the most stable, reliable, and best-shaped furrow for that
particular tobacco stream (and dispensing head).
[0062] The various embodiments described herein can be used to
disperse a wide range of additives, including flavourants, such as
menthol, binders or adhesives, and so on. The additive can be in
any appropriate form, such as a solution, undiluted, etc. The type
of head used for dispersing the additive (e.g. atomising spray,
hypodermic needle, etc) may depend on the particular properties of
the desired additive. Likewise, in some cases the head may require
heating for proper dispersal of the additive (for example, if the
additive is otherwise rather viscous at room temperature).
[0063] In summary, the skilled person will be aware of many
possible modifications and variations on the embodiments so far
described. For example, although the present approach has been
described generally in the context of cigarette manufacture, it can
be applied to other tobacco products, e.g. cigars. Accordingly, the
scope of the present invention is defined by the appended claims
and their equivalents.
* * * * *
References