U.S. patent application number 15/534151 was filed with the patent office on 2017-12-21 for a smoking article, a filter and a method of manufacturing a smoking article.
The applicant listed for this patent is British American Tobacco (Investments) Limited. Invention is credited to Mark AUSTIN, Mark BAILEY, Lisa HARVEY, Karl KALJURA, Sydney TAVERN, Tina WHITTON.
Application Number | 20170360084 15/534151 |
Document ID | / |
Family ID | 52425626 |
Filed Date | 2017-12-21 |
United States Patent
Application |
20170360084 |
Kind Code |
A1 |
KALJURA; Karl ; et
al. |
December 21, 2017 |
A smoking article, a filter and a method of manufacturing a smoking
article
Abstract
A smoking article includes a filter arrangement comprising a
first filter section and a second filter section, the second filter
section being located downstream of the first filter section, and a
ventilation arrangement configured to provide a user controllable
level of ventilation into the first filter section. A resistance to
gaseous flow through the length of the second filter section is
lower than a resistance to gaseous flow through the length of the
first filter section, and the resistance to gaseous flow through
the length of the filter arrangement remains substantially constant
as the level of ventilation is varied.
Inventors: |
KALJURA; Karl; (London,
GB) ; WHITTON; Tina; (London, GB) ; BAILEY;
Mark; (London, GB) ; TAVERN; Sydney; (London,
GB) ; HARVEY; Lisa; (London, GB) ; AUSTIN;
Mark; (London, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
British American Tobacco (Investments) Limited |
London |
|
GB |
|
|
Family ID: |
52425626 |
Appl. No.: |
15/534151 |
Filed: |
December 7, 2015 |
PCT Filed: |
December 7, 2015 |
PCT NO: |
PCT/GB2015/053744 |
371 Date: |
June 8, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24C 5/52 20130101; A24D
3/041 20130101; A24D 3/043 20130101 |
International
Class: |
A24D 3/04 20060101
A24D003/04; A24C 5/52 20060101 A24C005/52 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 8, 2014 |
GB |
1421803.6 |
Claims
1. A smoking article comprising: a filter arrangement comprising a
first filter section and a second filter section, the second filter
section being located downstream of the first filter section; and a
ventilation arrangement configured to provide a user controllable
level of ventilation into the first filter section, wherein the
smoking article comprises a first part and a second part and the
level of ventilation can be selected by selecting a position of the
second part relative to the first part; wherein a resistance to
gaseous flow through the length of the second filter section is
lower than a resistance to gaseous flow through the length of the
first filter section; and the resistance to gaseous flow through
the length of the filter arrangement remains substantially constant
as the level of ventilation is varied.
2. The smoking article as claimed in claim 1, wherein the first
filter section has a first tow weight of fibrous filtration
material, and the second filter section has a second tow weight of
fibrous filtration material; and the second tow weight of fibrous
filtration material is lower than the first tow weight of fibrous
material.
3. The smoking article as claimed in claim 1, wherein the pressure
drop per unit length of the first filter section is more than 5
mmH2O/mm, and the pressure drop per unit length of the second
filter section is less than 5 mmH2O/mm.
4. The smoking article as claimed in claim 1, wherein the
resistance to gaseous flow through the second filter section is
lower than the resistance to gaseous flow through the first filter
section by at least a multiple value selected from one of: 2, 3, 4,
5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15.
5. The smoking article as claimed in claim 1, wherein the first
filter section is formed from a first homogenous filtration
material, and the second filter section is formed from a second
homogenous filtration material.
6. The smoking article as claimed in claim 1, wherein the second
filter section is separate from the first filter section, and/or
moveable relative to the first filter section to control the
ventilation into the first filter section.
7. The smoking article as claimed in claim 1, wherein the second
part further comprises a sleeve configured to move relative to the
first filter section, wherein the second filter section is fixed
within the sleeve, and the level of ventilation is varied by
altering a position of the sleeve relative to the first filter
section.
8. The smoking article as claimed in claim 7, wherein the sleeve is
rotatable with respect to the first filter section, and the level
of ventilation is varied by altering an angular position of the
sleeve relative to the first filter section.
9. The smoking article as claimed in claim 1, wherein the first
filter section has a length of 5 to 25 mm, the second filter
section has a length of 5 to 25 mm, and/or the ventilation
arrangement provides ventilating air at 6 to 35 mm from a mouth end
of the smoking article.
10. The smoking article as claimed in claim 1, wherein the first
and second filter sections comprise tow filaments, and the first
filter section differs from the second filter section by one or
more of: tow weight, number of tow filaments in unit volume,
cross-section of tow filaments and degree of crimping.
11. The smoking article as claimed in claim 1, wherein the second
filter section comprises at least one air passage extending
longitudinally through the length thereof.
12. The smoking article as claimed in claim 11, wherein the air
passage has a diameter of between 1 and 7 mm.
13. The smoking article as claimed in claim 1, wherein the second
filter section comprises fibrous filtration material formed having
an annular cross section.
14. The smoking article as claimed in claim 1, wherein the second
filter section comprises a tube of fibrous filtration material and
the air passage extends along a central longitudinal axis through
the length of the second filter section.
15. A filter for a smoking article comprising: a filter arrangement
comprising a first filter section and a second filter section, the
second filter section being located downstream of the first filter
section; and a ventilation arrangement configured to provide a user
controllable level of ventilation into the first filter section,
wherein the filter comprises a first part and a second part and the
level of ventilation can be selected by selecting a position of the
second part relative to the first part; wherein a resistance to
gaseous flow through the length of the second filter section is
lower than a resistance to gaseous flow through the length of the
first filter section; and the resistance to gaseous flow through
the length of the filter arrangement remains substantially constant
as the level of ventilation is varied.
16. A method of manufacturing a smoking article, the method
comprising: forming a first filter section with a first resistance
to gaseous flow through its length; forming a separate second
filter section with a second resistance to gaseous flow through its
length, wherein the second resistance to gaseous flow is lower than
the first resistance to gaseous flow; and assembling the first
filter section and second filter section with one or more
additional components to form the smoking article such that the
second filter section is located downstream of the first filter
section in the smoking article, wherein the smoking article is
configured to allow the ingress of a selectively variable amount of
air.
Description
TECHNICAL FIELD
[0001] Embodiments of the invention relate to a smoking article, a
filter and a method of manufacturing a smoking article.
BACKGROUND
[0002] The resistance to draw of a smoking article is a measure of
the pressure required to force smoke through the smoking article at
a certain specified rate. A smoking article can be configured by
the manufacturing process to have a resistance to draw within a
pre-defined range. The resistance to draw through a smoking article
generally drops with increased ventilation.
SUMMARY
[0003] Embodiments of the invention provide, in a first aspect, a
smoking article comprising a filter arrangement comprising a first
filter section and a second filter section, the second filter
section being located downstream of the first filter section and a
ventilation arrangement configured to provide a user controllable
level of ventilation into the first filter section, wherein a
resistance to gaseous flow through the length of the second filter
section is lower than a resistance to gaseous flow through the
length of the first filter section, and the resistance to gaseous
flow through the length of the filter arrangement remains
substantially constant as the level of ventilation is varied.
[0004] The first filter section can have a first tow weight of
fibrous filtration material, and the second filter section can have
a second tow weight of fibrous filtration material and the second
tow weight of fibrous filtration material is lower than the first
tow weight of fibrous material.
[0005] The pressure drop per unit length of the first filter
section can be more than 5 mmH.sub.2O/mm, and the pressure drop per
unit length of the second filter section can be less than 5
mmH.sub.2O/mm. The resistance to gaseous flow through the second
filter section can be more than 15 times lower than the resistance
to gaseous flow through the first filter section.
[0006] The first filter section can be formed from a first
homogenous filtration material, and the second filter section can
be formed from a second homogenous filtration material.
[0007] The second filter section can be separate from the first
filter section, and/or moveable relative to the first filter
section to control the ventilation into the first filter
section.
[0008] The smoking article can further comprise a sleeve configured
to move relative to the first filter section, wherein the second
filter section is fixed within the sleeve, and the level of
ventilation is varied by altering a position of the sleeve relative
to the first filter section.
[0009] The sleeve can be rotatable with respect to the first filter
section, and the level of ventilation can be varied by altering an
angular position of the sleeve relative to the first filter
section.
[0010] The first filter section can have a length of 5 to 25 mm,
the second filter section can have a length of 5 to 25 mm, and/or
the ventilation arrangement can provide ventilating air at 6 mm to
35 mm from a mouth end of the smoking article.
[0011] The first and second filter sections can comprise tow
filaments, and the first filter section can differ from the second
filter section by one or more of: tow weight, number of tow
filaments in unit volume, cross-section of tow filaments and degree
of crimping.
[0012] The second filter section can comprise at least one air
passage extending longitudinally through the length thereof.
[0013] The air passage can have a diameter of between 1 and 7
mm.
[0014] The second filter section can comprise fibrous filtration
material formed having an annular cross section.
[0015] The second filter section can comprise a tube of fibrous
filtration material and the air passage can extend along a central
longitudinal axis through the length of the second filter
section.
[0016] Embodiments of the invention provide, in a second aspect, a
method of manufacturing a smoking article, the method comprising
forming a first filter section with a first resistance to gaseous
flow through its length, forming a separate second filter section
with a second resistance to gaseous flow through its length,
wherein the second resistance to gaseous flow is lower than the
first resistance to gaseous flow, and assembling the first filter
section and second filter section with one or more additional
components to form the smoking article, wherein the smoking article
is configured to allow the ingress of a selectively variable amount
of air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Various embodiments of the invention will now be described,
by way of example only, with reference to the accompanying
drawings, in which:
[0018] FIG. 1 is a longitudinal cross-sectional view of a part of a
smoking article according to a first embodiment of the
invention;
[0019] FIG. 2 is a perspective view of the smoking article
illustrated in FIG. 1;
[0020] FIG. 3 is a longitudinal cross-sectional view of a part of a
smoking article according to a second embodiment of the
invention;
[0021] FIG. 4 is a perspective view of the smoking article
illustrated in FIG. 3;
[0022] FIG. 5 is a graph showing the relationship between level of
ventilation and open cigarette pressure drop (PD) for an example
conventional smoking article and a smoking article according to the
invention;
[0023] FIG. 6a is a plan view of a blank forming a wrapper for a
smoking article according to a third embodiment of the
invention;
[0024] FIG. 6b is a plan view of a rod article to which the blank
of FIG. 6a is applied to form the smoking article according to the
third embodiment of the invention;
[0025] FIG. 7a is a plan view of a blank for forming a wrapper for
a smoking article according to a fourth embodiment;
[0026] FIG. 7b is a longitudinal cross-sectional view of the
smoking article according to the fourth embodiment; and
[0027] FIG. 8 is a schematic flow diagram showing a method of
manufacturing a smoking article.
DETAILED DESCRIPTION
[0028] FIG. 1 illustrates a smoking article 10 according to a first
embodiment. The smoking article 10 is a cigarette in the present
example. However, other smoking articles can be used, and the term
smoking article is used to also refer to cigars or cigarillos,
whether based on tobacco, tobacco derivatives, expanded tobacco,
reconstituted tobacco or tobacco substitutes and also heat-not-burn
products (i.e. products in which flavour is generated from a
smoking material by the application of heat without causing
combustion of the material) and aerosol generating products such as
e-cigarettes. For convenience, these will be referred to as
"smoking articles" in this specification.
[0029] Smoking articles such as cigarettes and their formats are
often named according to the cigarette length: "regular" (typically
in the range 68-75 mm, e.g. from about 68 mm to about 72 mm),
"short" or "mini" (68 mm or less), "king-size" (typically in the
range 75-91 mm, e.g. from about 79 mm to about 88 mm), "long" or
"super-king" (typically in the range 91-105 mm, e.g. from about 94
mm to about 101 mm) and "ultra-long" (typically in the range from
about no mm to about 121 mm).
[0030] They are also named according to the cigarette
circumference: "regular" (about 23-25 mm), "wide" (greater than 25
mm), "slim" (about 22-23 mm), "demi-slim" (about 19-22 mm),
"super-slim" (about 16-19 mm), and "micro-slim" (less than about 16
mm). Accordingly, a cigarette in a king-size, super-slim format
will, for example, have a length of about 83 mm and a circumference
of about 17 mm. Cigarettes in the regular, king-size format are
preferred by many customers, namely with a circumference of from 23
to 25 mm and an overall length of from 75 to 91 mm.
[0031] Each format may be produced with filters of different
lengths, smaller filters being generally used in formats of smaller
lengths and circumferences. Typically the filter length will be
from 15 mm, associated with short, regular formats, to 30 mm,
associated with ultra-long super-slim formats. The tipping paper
will have a greater length than the filter, for example from 3 to
10 mm longer.
[0032] Smoking articles and filters described hereinafter can be
manufactured in any of the above formats. The smoking article can,
for instance, be from 70 to 100 mm in length and from 14 to 25 mm
in circumference.
[0033] The terms `upstream` and `downstream` used herein are
relative terms defined in relation to the direction of mainstream
smoke (or other aerosol) drawn though a smoking article in use.
[0034] The smoking article 10 of the example of FIG. 1 comprises a
source of smokable material, such as tobacco, attached to a filter
arrangement which comprises a first filter section 12 and a second
filter section 14. The source of smokable material is in the form
of a tobacco rod 11, which is attached to the first filter section
12. The second filter section 14 is located downstream of the first
filter section 12 and tobacco rod 11. A ventilation arrangement 17
provides a user controllable variable level of ventilation into the
first filter section 12, as described in more detail below.
[0035] The resistance to gaseous flow through the length of the
second filter section is lower than the resistance to gaseous flow
through the length of the first filter section; and the resistance
to gaseous flow through the length of the filter arrangement
remains substantially constant as the level of ventilation is
varied. The reduced resistance of the second filter section 14
results in the first filter section 12 having a greater influence
on the overall resistance to gaseous flow of the filter
arrangement. As ventilation is increased into the second filter
section 14, a lower resistance path is created for flow through the
filter arrangement, therefore significantly reducing the resistance
to draw experienced by the consumer, when compared to lower levels
of ventilation. The reduced resistance of the second filter section
14 when compared to the first filter section therefore enhances the
change in the resistance to draw experience by the consumer as the
ventilation is altered, providing the consumer with a greater
sensory indication that the ventilation has been changed.
[0036] The smoking article 10 comprises a first part comprising the
tobacco rod 11 and the first filter section 12. The tobacco rod 11
and first filter section 12 are connected with a covering layer to
affix the first filter section to the tobacco rod, which is formed
of tipping paper. The tobacco rod 11 and first filter section 12
are referred to as a tobacco unit. The elongate tobacco rod 11 and
first filter section 12 define a longitudinal axis of the smoking
article.
[0037] A second part of the smoking article comprises the second
filter section 14 and a sleeve 13 which is movable relative to the
first part of the smoking article. The sleeve is in the form of a
tube extending around the circumference of the tobacco rod 11
and/or first filter section 12. The tube can be cylindrical. The
sleeve 13 is formed of paper. The second filter section 14 is
securely attached and fixed within the sleeve. The first and second
filter sections 12,14 each comprise filtration material which is
wrapped in a sheet material, which may be paper, e.g. plugwrap. The
first and second filter sections form a filter arrangement. The
first filter section 12 is upstream of the second filter section
14. The second filter section 14 is at a mouth end of the sleeve
13, adjacent to, and separate from, the first filter section 12.
Alternatively, the first and second filter sections are
connected.
[0038] The tobacco rod 11 and attached first filter section 12 are
described as connected by tipping paper (not shown). The tipping
paper is a standard tipping paper, or a relatively thick recessed
tipping paper, or a board type tipping paper.
[0039] The smoking article 10 is provided with the ventilation
arrangement 17 configured to allow adjustment of a ventilation of
the smoking article 10. The ventilation arrangement 17 comprises
one or more second ventilation area 15 on the sleeve 13, upstream
of the second filter section 14. The smoking article further
comprises one or more first ventilation area 16 around the first
filter section 12. For example, the one or more first ventilation
area 16 is defined by a layer(s) of sheet material around the first
filter section or around the filtration material of the first
filter section. The ventilation arrangement 17 provides for
ventilating air to enter into the first filter section. The terms
"upstream" and "downstream" are relative to the direction of the
passage of smoke along the longitudinal axis of the smoking article
10, i.e. "downstream" indicates in a direction toward the mouth end
of the smoking article 10.
[0040] Ventilation areas 15,16 are formed as ventilation apertures
or air permeable material. In some embodiments, when ventilation
areas 15 on the sleeve 13 are exposed, air can flow into the body
of the smoking article 10. When second ventilation areas 15 on the
sleeve 13 and the corresponding first ventilation areas 16 around
the first filter section 12 are aligned, air can flow into the body
of the smoking article 10. Ventilation areas 15,16 are aligned by
rotation of the first part of the smoking article relative to the
second part. In particular, the ventilation is controlled by
rotation of the sleeve 13 relative to the first filter section 12.
The ventilation arrangement 17 provides a selectable variable level
of ventilation controlled by adjusting the overlap of the second
ventilation area 15 with the first ventilation area 16. The amount
of ventilation depends on the effective ventilating area, which is
determined by the area of the overlap of the first and second
ventilation areas. The level of ventilation can be selected by
selecting a position of the second part relative to the first part
e.g. by rotation of the second part relative to the first part.
Thus, the ventilation arrangement 17 provides for a variable size
of effective ventilation area, providing a variable intake of air,
substantially upstream of the second filter section.
[0041] The first filter section 12 and second filter section 14 are
made of a known filtration material. The filtration material for
both filter sections can be tow, for example, cellulose acetate
tow. The filtration material of the first filter section is
homogenous, and independently, the filtration material of the
second filter section is homogenous. The term "homogenous" is used
to mean that the filtration material is substantially uniform
throughout each filter section, and in particular, is uniform in a
longitudinal and/or radial direction through each of the first and
second filter sections 12,14. At least one physical property of the
homogenous first filter section is different to the homogenous
second filter section.
[0042] The first filter section 12 provides a first resistance to
gaseous flow through the length thereof. The resistance to gaseous
flow through the length of the first filter section is determined
by the filtration material of the first filter section. The
resistance to gaseous flow indicates the pressure required to draw
smoke through the length of the first filter section 12 at a
particular rate. The term "pressure drop" can be used in place of
"resistance to gaseous flow". Pressure drop can be given in units
of distance height of water (mmH.sub.2O). The first filter section
has a first pressure drop per unit length, or resistance to gaseous
flow per unit length, which is constant in a longitudinal direction
through the first filter section 12. Pressure drop per unit length
is given per millimetre, i.e. in units of mmH.sub.2O/mm. The first
pressure drop per unit length is determined by the filtration
material of the first filter section.
[0043] The second filter section 14 provides a second resistance to
gaseous flow through the length thereof. The resistance to gaseous
flow through the length of the second filter section is determined
by the filtration material of the second filter section 14. The
resistance to gaseous flow through the length of the second filter
section 14 defines a second pressure drop. The second pressure drop
or resistance to gaseous flow indicates the pressure required to
draw smoke through the length of the second filter section 14 at a
particular rate. The second resistance to gaseous flow (or pressure
drop) per unit length is substantially constant in a longitudinal
direction through the second filter section 14. The second filter
section 14 can be considered as comprising a filtration material
having a second pressure drop per unit length.
[0044] In aspects of the present invention, the resistance to
gaseous flow through the length of the first filter section 12 is
greater than the resistance to gaseous flow through the length of
the second filter section 14. In another aspect, the tow weight of
the second filter section 14 is lower than the tow weight of the
first filter section 12. The second density provided by the second
filter section 14 is lower than the first density provided by the
first filter section 12. Optionally, the first pressure drop across
the first filter section 12 is greater than the second pressure
drop across the second filter section 14.
[0045] The one or more ventilation areas 15,16 allowing selectable
ventilation are upstream of the second filter section 14. The
relatively low resistance to draw through the length of the filter
arrangement downstream of the ventilation area 15 provides an
increased variation in an overall resistance to draw from the mouth
end of the smoking article 10, as ventilation is varied.
[0046] The ventilation arrangement 17 is located substantially
upstream of the second filter section 14. Ventilation of a smoking
article 10 reduces the resistance to draw from the mouth end of the
smoking article 10. The ingress of ventilating air reduces the
volume of air drawn through the length of smoking article 10
upstream of the ventilation areas, reducing the volume of air which
experiences the resistance to gaseous flow upstream of the
ventilating areas. The ventilating air enters directly with
substantially no resistance, so the overall resistance to draw is
reduced. In particular, the ingress of air through the ventilation
areas 15 reduces the effect of the resistance to gaseous flow
through the section of the smoking article 10 upstream of the
ventilation areas 15. The effect of the resistance to gaseous flow
through the smoking article 10 downstream of the ventilation areas
15 is unchanged by variations in ventilation.
[0047] The relatively low resistance to gaseous flow provided by
the lower density of the second filter section 14 (relative to the
first filter section 12) downstream of the ventilation areas 15
defines a minority of the resistance to gaseous flow through the
full length of the filter arrangement. Alternatively, the second
filter section 14 provides a relatively small contribution to the
overall resistance to draw from the mouth end of the smoking
article 10. The contribution of the one or more sections upstream
of the ventilation area 15 on the overall resistance to draw is
greater by comparison. The ingress of air reduces the effect of the
pressure drop or resistance to gaseous flow through the upstream
section only, and the downstream section with a lower resistance to
gaseous flow or pressure drop is unaffected by the ventilation.
Therefore, a relatively large proportion of the overall resistance
to draw from the mouth end of the smoking article 10 is affected by
the change in ventilation of the smoking article 10. The decreased
density of the second filter section 14 downstream of the
ventilation areas 15 increases the proportion of the resistance to
draw which is affected by the change in ventilation of the smoking
article 10. The decreased density of the second filter section 15
provides an increase in the effect of an increased ventilation on
the overall resistance to draw from the mouth end of the smoking
article 10.
[0048] As the level of ventilation is varied, the resistance to
draw from the mouth end of the smoking article 10 also changes. As
the amount of ventilating air entering the smoking article 10
increases, the overall resistance to draw decreases. The relatively
low pressure drop or resistance to gaseous flow through the second
filter section 14 (e.g. achieved with a relatively low density of
filter material) provides a relatively large change in overall
resistance to draw caused by an increased level of ventilation.
Therefore, as the level of ventilation is varied over a range
selectable by the user, the resistance to draw from the mouth end
of the smoking article 10 varies over a relatively large range as a
result of the lower density of the second filter section 14. Thus,
the variation in resistance to draw from the mouth end of the
smoking article is accentuated as the ventilation is varied. This
can give the user a greater sensory indication that the ventilation
level has been varied.
[0049] In some examples of the invention, the second filter section
has a pressure drop per unit length of less than 5 mmH.sub.2O/mm.
Alternatively, the second filter section has a pressure drop per
unit length of less than a value selected from: 4 mmH.sub.2O/mm, 3
mmH.sub.2O/mm, 2 mmH.sub.2O/mm, 1.5 mmH.sub.2O/mm, and 1
mmH.sub.2O/mm.
[0050] In some examples of the invention, the first filter section
has a pressure drop per unit length of more than 5 mmH.sub.2O/mm.
Alternatively, the first filter section has a pressure drop per
unit length of more than a value selected from: 6 mmH.sub.2O/mm, 7
mmH.sub.2O/mm, 8 mmH.sub.2O/mm, 9 mmH.sub.2O/mm, 10 mmH.sub.2O/mm,
11 mmH.sub.2O/mm, and 12 mmH.sub.2O/mm.
[0051] In some aspects, the pressure drop per unit length of the
second filter section is between 1 and 5 mmH.sub.2O/mm, and the
pressure drop per unit length of the first filter section is
between 5 and 15 mmH.sub.2O/mm. In some examples, the pressure drop
per unit length of the second filter section is less than 5
mmH.sub.2O/mm, and the pressure drop per unit length of the first
filter section is more than 5 mmH.sub.2O/mm. The upstream filter
section has a pressure drop per unit length which is higher than a
pressure drop per unit length of the downstream filter section. The
upstream filter section has a pressure drop per unit length which
is higher than any of the example values specified, and a pressure
drop per unit length of the downstream filter section is lower than
any of the example values specified.
[0052] In some examples, the resistance to gaseous flow through the
length of the second filter section is lower than the first filter
section by at least a multiple value selected from one of: 2, 3, 4,
5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15.
[0053] For example, the resistance to gaseous flow through the
length of the second filter section is between 2 and 15 times lower
than through the length of the first filter section. Optionally,
the second pressure drop per unit length of the second filter
section is between 5 and 12 times lower than the first pressure
drop per unit length of the first filter section.
[0054] In some aspects, the ventilation arrangement 17 is located
at a downstream end of the first filter section 12. In some
examples, the ventilation arrangement is located less than 10 mm
from the downstream end of the first filter section 12.
[0055] The pressure drop per unit length of the first and second
filter sections is determined (at least partially) by the physical
structure of the filtration material forming the filter sections.
The first and second filter sections can both comprise fibrous
material, comprising tow filaments. For a filtration material
comprising tow filaments, the pressure drop per unit length can be
determined by the amount or number of tow filaments in a particular
volume or length. The tow weight is a measure of the amount of tow
fibres in a certain volume. The pressure drop per unit length can
also be determined by the cross-section of the tow filaments. For
example, the tow filaments can have an X-shaped cross-section or a
Y-shaped cross-section. The cross-sectional area can also affect
the pressure drop per unit length. The tow weight can provides an
indication of the density of a fibrous material within the filter
section. The pressure drop per unit length can also be determined
by the amount or degree of crimping (i.e. folding) of the
filaments, during the manufacturing processes. These factors
affecting the pressure drop per unit length of the filter sections
are known, and can be selected to obtain the required pressure drop
per unit length for each of the first and second filter sections
individually. Thus, the first and second filter sections comprise
filtration material which has a physical property determined by a
different selection of any one or more of the above
characteristics. The first and second filter sections are
manufactured using filtration material formed or treated to have
the required properties, for example as above, providing the
different pressure drop per unit length for the first and second
filter sections.
[0056] FIG. 2 is a perspective view of the part of the smoking
article 10 illustrated in FIG. 1. As illustrated in FIG. 2, the
tobacco rod 11 and first filter section 12 are dimensioned to
rotate as a unit around a longitudinal axis within the sleeve 13. A
restraining means (not shown) retains the first part and second
part in a fixed longitudinal arrangement, and prevents extension of
the smoking article 10. Thus, the first part cannot slide
longitudinally relative to the second part, i.e. the sleeve is not
movable longitudinally relative to the tobacco unit.
[0057] The level of ventilation can be selected by selecting an
angular position of the sleeve 13 relative to the first filter
section 12.
[0058] In some examples, the ventilation areas 15 are configured to
increase in size non-linearly with respect to angular position. The
ventilation areas 15 are configured such that the level of
ventilation has a substantially linear dependence on the angular
position of the sleeve 13 relative to the first filter section
12.
[0059] In some aspects, the one or more ventilation areas 15
maintain a fixed longitudinal position relative to the first and
second filter sections, when the sleeve 13 is rotated relative to
the first filter section 12.
[0060] In the present embodiment, the second filter section 14 is
securely attached and fixed within the sleeve 13. Rotation of the
second filter section 14 causes a corresponding rotation of the
sleeve 13 relative the first filter section 12.
[0061] By selecting a different angular position of the second
filter section 14 relative to the first filter section 12, the
registry between the ventilation areas 15 in the sleeve 13 and the
ventilation areas 16 in the sheet material or plugwrap around the
first filter section 12 can be selectively increased or decreased.
The level of ventilation in the smoking article 10 can therefore be
increased or decreased.
[0062] FIG. 3 is a longitudinal cross-sectional view of a part of a
smoking article according to a second embodiment of the invention.
The overall layout is similar to the example of FIGS. 1 and 2
described above, the same parts having the same reference numerals,
and parts other than those described remaining unchanged.
[0063] In the embodiment of FIG. 3, the second filter section 24 is
formed to have an air passage 28 passing longitudinally through its
centre. The second filter section 24 and air passage 28 form a
tubular filter section extending along the longitudinal axis of the
smoking article 20. The second filter section 24 is formed from
fibrous filtration material having an annular cross-section.
Alternatively, the air passage 28 may pass longitudinally along a
non-central path through the second filter section. Optionally, the
second filter section may be formed to have a plurality of air
passages which pass longitudinally therethrough.
[0064] The air passage 28 reduces the resistance to gaseous flow
through the length of the second filter section 24. The resistance
to gaseous flow through the length of the second filter section 24
is lower than the resistance to gaseous flow through the length of
the first filter section 12.
[0065] The dimensions of the second filter section 24 will depend
on various factors such as the desired resistance to draw or the
second filter section 24 relative to the first filter section 12,
the properties of the filter tow and the level of plasticiser, such
as triacetin, added to the filter tow. However, in examples herein,
the outer circumference of the second filter section is between 15
and 25 mm, for instance between 22 mm and 25 mm, or 23.95 mm. The
internal diameter of the air passage 28 is preferably between 1 mm
and 7 mm, for instance between 3 mm and 6 mm, or 4.8 mm.
[0066] FIG. 4 is a perspective view of the smoking article
illustrated in FIG. 3. As illustrated in FIG. 4, the air passage 28
is located to pass longitudinally through the centre of the second
filter section 24. Alternatively, the air passage 28 may pass
longitudinally along a non-central path through the second filter
section 24. Optionally, the second filter section 24 may be formed
to have a plurality of air passages which pass longitudinally
therethrough.
EXAMPLE
[0067] Table 1 below illustrates calculated values for the
resistance to draw from the mouth end of a conventional "Smoking
Article 1" compared with calculated values for the resistance to
draw from the mouth end of an example "Smoking Article 2",
according to an example of the invention. Each smoking article has
a filter with total length 27 mm, and variable ventilation system
allowing ingress of air at a distance 16.5 mm from the mouth end of
the filter. The filter is formed of the first and second filter
sections which are axially aligned. The mouth end filter section
(second filter section) is 8 mm long, and the tobacco end filter
section (first filter section) is 19 mm long. Both smoking articles
have an identical tobacco rod with a resistance to draw (pressure
drop) of 43.43 mm H.sub.2O.
[0068] The conventional filter of Smoking Article 1 has a provides
a substantially uniform pressure drop per unit length of
approximately 5 mmH.sub.2O/mm, for both first and second filter
sections. The pressure drop is 85 mmH.sub.2O for the first filter
section with a length of 19 mm, and a pressure drop of 40
mmH.sub.2O for the second filter section with a length of 8 mm.
[0069] In the example of Smoking Article 2, according to the
invention, the second filter section is an 8 mm filter section at
the mouth end of the filter, which has a pressure drop of 8
mmH.sub.2O. This provides a relatively low pressure drop per unit
length of 1 mmH.sub.2O/mm. The upstream first filter section has a
length of 19 mm adjacent the tobacco rod, and has a relatively high
pressure drop per unit length. This provides a pressure drop per
unit length of 7.11 mmH.sub.2O/mm.
TABLE-US-00001 TABLE 1 Smoking Article 1 Smoking Article (example
conventional 2 (example smoking article) of invention) Pressure
Pressure drop (mmH.sub.2O) drop (mmH.sub.2O) First filter section
(19 mm) 85 135 PD Second filter section (8 mm) 40 8 PD PD of filter
downstream of 78.03 68.39 vent PD of filter upstream of vent 46.97
74.61 PD Tobacco Rod 43.43 43.43 Total PD at 40% ventilation 132.27
139.22 Total PD at 60% ventilation 114.19 114.61 Total PD at 80%
ventilation 96.11 92.00
[0070] The pressure drop through the full smoking article
(including tobacco rod) is determined for ventilation values with a
level of ventilation between 40% and 80% ventilated. For the
conventional Smoking Article 1 the pressure drop varies from 132.27
to 96.11 mmH.sub.2O ventilation as ventilation increases. However,
in the Smoking Article 2, according to the invention, the pressure
drop varies from 139.22 mmH.sub.2O to 92 mmH.sub.2O over the same
ventilation range. Thus, the drop of 47.22 mm H.sub.2O provided by
the invention, compared with only 36.16 mm H.sub.2O for the
conventional smoking article, provides an increase change in
pressure drop (i.e. more varied resistance to draw from the mouth
end) when varying the ventilation of the smoking article. These
results are illustrated in FIG. 5, in which the y-axis indicates
pressure drop and the x-axis indicated the percentage
ventilation.
[0071] In some embodiments, the pressure drop downstream of the
ventilation arrangement 17 is decreased further by reducing the
distance between the mouth end of the smoking article and the one
or more ventilation areas.
[0072] In some examples of the invention, the ventilation areas
allow the ingress of air at a distance from the mouth end which is
less than 15 mm. Alternatively, the distance from the mouth end of
the ventilation are is less than a value selected from: 14 mm, 13
mm, 12 mm, 11 mm, and 10 mm.
[0073] FIG. 6a is a plan view of a blank 30 forming a wrapper for a
smoking article according to a third embodiment of the invention.
FIG. 6b is a plan view of a rod article 32 to which the blank 30 of
FIG. 6a is applied to form the smoking article. The smoking article
comprising the blank 30 has substantially the same functions as
described above. Features have the same arrangement and function
unless otherwise described.
[0074] The blank 30 is configured to wrap twice only around the
whole circumference of the rod article 32. The blank 30 is
configured to define two complete layers extending around the
circumference of the rod article 32, and comprises areas to define
an inner layer and an outer layer.
[0075] The blank 30 comprises a control element 34 movable in a
channel 36, configured to control ventilation and limit
movement.
[0076] The control element 34 is movable circumferentially within a
limited range. The control element 34 is movable between a first
engaging surface and a second engaging surface. The first engaging
surface and second engaging surface define a circumferentially
extending channel 36 in which the control element 34 is
movable.
[0077] The control element 34 defines first and second limiting
surfaces 34a, 34b at the edges of the control element in the
direction of movement, i.e. at the circumferential edge of the
control element 34. Contact of the first and second limiting
surfaces 34a, 34b of the control element 34 between the first
engaging surface and the second engaging surface limits relative
rotation between the first and second parts of the smoking
article.
[0078] The first and second limiting surfaces 34a, 34b extend at an
angle to a longitudinal axis of the smoking article. The first and
second engaging surfaces also extend at an angle to the
longitudinal axis of the smoking article, and/or at an angle to the
axis of movement of the control element. The first and second
engaging surfaces extend at the same angle and/or have a
complementary shape to the first and second limiting surfaces 34a,
34b.
[0079] The blank 30 comprises the first and second spacing sections
38a, 38b. The first and second spacing sections 38a, 38b are
configured to directly attach to and circumscribe the rod articles.
The first and second spacing sections 38a, 38b have the function of
spacing a plurality of optional indexing surfaces at a correct
radial distance to allow indexing. The first and second spacing
sections 38a, 38b are longitudinally spaced apart.
[0080] The control element 34 is configured to directly overlie one
of the spacing sections 38a, 38b. The control element is movable
over the spacing section 38a, the spacing section providing a
substantially smooth exterior surface over which the control
element is easily moved.
[0081] Referring to FIG. 6b, the rod article 32 includes a tobacco
rod 11, similar to those previously described, and first and second
filter sections 40, 42 downstream of the tobacco rod 11. The second
filter section 42 is provided, as a tubular section substantially
similar to the second filter section 24 described in relation to
the second embodiment, downstream of the first filter section 41
and tobacco rod 11, at the mouth end of the smoking article. The
first filter section 40 is provided between the second filter
section 42 and the tobacco rod 11. When the blank 30 is wrapped
around the rod article 32, the control element 34 is spaced by the
spacing section from the first filter section 40. The first filter
section 40 optionally defines a first indexing surface 40a, and so
does not provide a smooth surface for the control element.
[0082] The first and second spacing sections 38a, 38b are
optionally connected by a spacer connection 44. The first and
second spacing sections 38a, 38b extend circumferentially over the
two layers of the first blank 30. The spacer connection 44 is
adjacent a leading edge of the first blank 30, i.e. the point on
the blank 30 first wrapped around the rod article 32.
[0083] The spacer connection 44 and longitudinally adjacent areas
of the spacing sections 38a, 38b are initially affixed to the rod
article to begin wrapping of the first blank 30, for example, with
adhesive. The spacer connection 44 provides for the blank 30 to
have a single initial area of attachment to the rod article 32. The
spacing sections 38a, 38b are not affixed as independent elongate
sections of sheet material, requiring separate attachment to the
rod article 32. Thus, the connection of the leading edges of the
spacing sections 38a, 38b improves initial attachment of the blank
30 to the rod articles.
[0084] The spacer connection 44 has a trailing edge 44a at a
circumferentially opposite end of the spacer connection 44 to the
leading edge. The spacer connection trailing edge 44a extends
between the first and second spacing sections 38a, 38b. The spacer
connection trailing edge 44a extends at an angle to a longitudinal
axis of the smoking article.
[0085] The control element 34 is formed on a support section 46 of
the blank 1401. The control element 34 defines the longitudinally
extreme area of the section to which the control element is
attached. Thus, the first and second limiting surfaces 34a, 34b of
the control element 34 extend longitudinally beyond the section to
which the control element is attached. The support section 44 is
attached to the first and second spacing sections with frangible
connections. The frangible connections are circumferentially
extending line of perforations. The support section 46 extends one
time around the whole circumference of the smoking article, e.g. to
form a tube. The control element is curved as a part of that
tube.
[0086] The support section 46, optionally supports a second
indexing surface 48. In particular, the second indexing surface
optionally comprises a pawl 48 formed on a pawl support unit 50,
which is attached to the support section 46. The pawl 48 is
configured to extend between the first and second spacing sections
38a, 38b, and engage with the optional first indexing surface
40a.
[0087] The support section 46 comprises a support section leading
edge 46a. The support section leading edge 46a defines the initial
point of the support section 46 which is first wrapped around the
rod article 32. The support section leading edge 46a extends at an
angle to a longitudinal axis of the smoking article.
[0088] 30 A trailing edge 46b of the support section 46 extends
substantially parallel to the longitudinal axis of the smoking
article.
[0089] The spacer connection trailing edge 44a, support section
leading edge 46a and first and second spacing sections 38a, 38b
define an aperture 52 in the blank 30. The aperture 52 provides a
space in which the support section 46 is movable.
[0090] In some examples, the aperture 52 has a circumferential
extent which is greater than a circumferential extent of movement
of the control element 34. Thus, the spacer connection trailing
edge 44a does not determine the range of movement of the control
element 34.
[0091] The area of blank 30 forming the inner layer, e.g. on the
first spacing section 38a, comprises a ventilation area 54. In some
examples, the ventilation area 54 comprises a single aperture.
Alternatively, the ventilation area 54 comprises a plurality of
discrete permeable areas or apertures. For example, the apertures
are formed by electroperforation (EP).
[0092] The control element 34 has a further function in controlling
the ventilation of the smoking article. In particular, the control
element 34 directly controls the ventilation of the smoking article
by selectively covering one or more ventilation areas. The control
element 34 is configured to be movable over one or more ventilation
areas in a radially adjacent, and integrally formed, part of the
smoking article. The control element 34 is formed of a material
which is substantially impermeable to air, in particular, paper
which is not permeable to air. The control element 34 is configured
to cover the one or more ventilation areas of the smoking article,
such that ventilation air cannot enter the smoking article through
an area which is covered by the control element 34. The control
element is impermeable to air between the first and second limiting
surfaces 34a, 34b. The first and second limiting surfaces 34a, 34b
define both the limits of rotation and define the amount of
ventilation area which is covered or uncovered.
[0093] Thus, the control element 34 has the dual function of both
directly controlling a level of ventilation by covering a part of a
ventilation area and limiting relative movement of the first and
second parts of the smoking article between maximum and minimum
levels of ventilation.
[0094] In some aspects, the smoking article comprises a further
ventilation area 56. For example, the first filter section 40
comprises the further ventilation area 56. The ventilation area 54
is arranged to at least partially coincide with the further
ventilation area 56. The further ventilation area 56 comprises a
plurality of discrete ventilation areas or apertures, for example,
in a circumferentially extending line. The further ventilation area
56 can be formed by a laser. Generally, one or more of the
ventilation areas 54, 56 comprise a plurality of discrete
ventilation areas or apertures.
[0095] FIG. 7a is a plan view of a blank 60 forming a wrapper for a
smoking article according to a fourth embodiment. FIG. 7b is
longitudinal cross-sectional view of a smoking article 62 to which
the blank 60 of FIG. 7a has been applied. The smoking article 62
comprising the blank 60 has substantially the same functions as
described above. Features have the same arrangement and function
unless otherwise described.
[0096] Referring to FIG. 7b, the rod article 62 includes a tobacco
rod 11, similar to that previously described, and first and second
filter sections 12, 14 downstream of the tobacco rod 11. The second
filter section 14 is provided downstream of the first filter
section 12 and tobacco rod 11, at the mouth end of the smoking
article. The first filter section 12 is provided between the second
filter section 14 and the tobacco rod 11. The first filter section
12 is divided into a first part 12' and a second part 12'' by a cut
12''', allowing the first part 12' of the first filter section 12
to move relative to the second part 12''.
[0097] The blank 60 is configured to wrap twice, and in the present
example twice only, around the whole circumference of the rod
article 62. The blank 60 has a first section 60a which first wraps
around the rod article 62 forming an inner layer and a second
section 60b which then wraps around the first section 60a, forming
an outer layer. The blank 60 is therefore configured to define two
complete layers extending around the circumference of the rod
article 62, and comprises areas 60a, 60b to define an inner layer
and an outer layer.
[0098] The first section 60a of the blank 60 comprises a first end
portion 60a' connected to the second filter section 14 and to the
first part 12' of the first filter section 12, and therefore
connecting the second filter section 14 and the first part 12' of
the first filter section 12 together. The first section 60a of the
blank 60 also comprises a second end portion 60a'' connected to the
second part 12'' of the first filter section 12. The second section
60b of the blank 60 is separated into a first part 60b' and a
second part 60b'' by a cut 61.
[0099] The blank 60 comprises, on the first section 60a, a control
element 64 movable in a circumferentially extending channel 66,
configured to control ventilation and limit movement.
[0100] The control element 64 is movable circumferentially within a
limited range. The control element 64 is movable between a first
engaging surface and a second engaging surface. The first engaging
surface and second engaging surface define the circumferentially
extending channel 66 in which the control element 64 is
movable.
[0101] The control element 64 defines first and second limiting
surfaces 64a, 64b at the edges of the control element in the
direction of movement, i.e. at the circumferential edge of the
control element 64. Contact of the first and second limiting
surfaces 64a, 64b of the control element 64 with the first engaging
surface and the second engaging surface of the circumferentially
extending channel 66 limits relative rotation between the first and
second parts of the smoking article.
[0102] The first and second limiting surfaces 64a, 64b extend at an
angle to a longitudinal axis of the smoking article. The first and
second engaging surfaces also extend at an angle to the
longitudinal axis of the smoking article, and/or at an angle to the
axis of movement of the control element. The first and second
engaging surfaces extend at the same angle and/or have a
complementary shape to the first and second limiting surfaces 64a,
64b.
[0103] A longitudinal movement restricting arrangement 65 comprises
a sliding element 67 which is arranged to move between first and
second restricting elements 68a and 68b. Sliding element 67 is
attached to first and second restricting elements 68a and 68b with
a frangible connection. The frangible connection is a
circumferentially extending line of perforations. The part of the
blank including the sliding element 67, control element 64, first
and second restricting elements 68a and 68b and circumferentially
extending channel 66 extends one time around the whole
circumference of the smoking article, e.g. to form a tube. The
sliding element 67 is attached to first part 60b' of the second
section 60b of the blank 60, together with the first part 60a' of
the first section 60a of the blank, and therefore moves, together
with the first part 60a' of the first section 60a, the second
filter section 14 and the first part 12' of the first filter
section 12, relative to 30 the second part 60a'' of the first
section 60a of the blank 60 and the second part 12'' of the first
filter section 12.
[0104] The second section 60b of the blank 60 forming the outer
layer, comprises a ventilation area 69' at a location 69 on the
blank. In some examples, the ventilation area 69' comprises a
single aperture. Alternatively, the ventilation area 69' comprises
a plurality of discrete permeable areas or apertures. For example,
the apertures are formed by electroperforation (EP). The
ventilation area 69' is arranged to align with the channel 66 when
the blank 60 is wrapped around the rod article 62.
[0105] The control element 64 has a further function in controlling
the ventilation of the smoking article. In particular, the control
element 64 directly controls the ventilation of the smoking article
by selectively blocking one or more ventilation areas. The control
element 64 is configured to be movable relative to one or more
ventilation areas in a radially adjacent, and integrally formed,
part of the smoking article. The control element 64 is formed of a
material which is substantially impermeable to air, in particular,
paper which is not permeable to air. The control element 64 is
configured to move between the ventilation area 69' and the
underlying rod article 62 of the smoking article, such that
ventilation air cannot enter the smoking article through the
channel 66 which is blocked by the control element 64. The control
element is impermeable to air between the first and second limiting
surfaces 64a, 64b. The first and second limiting surfaces 64a, 64b
define both the limits of rotation and define the amount of
ventilation area which is covered or uncovered.
[0106] Thus, the control element 64 has the dual function of both
directly controlling a level of ventilation by covering a part of a
ventilation area and limiting relative movement of the first and
second parts of the smoking article between maximum and minimum
levels of ventilation.
[0107] In some embodiments, the first filter section 12 comprises
flavourant in the form of botanical particles. However, the first
filter section 12 can comprise other forms of flavourant, such as
one or more capsules, a thread loaded with flavourant, flavourant
dispersed in filter tow, flavour impregnated particles or a sheet
material comprising a flavourant, which lie upstream of the
ventilation area 69'. The level of ventilation in the smoking
article 10 controls the dilution of smoke which passes through the
first part of the smoking article 10 with air which enters the
smoking article 10 through the ventilation area 69'. Therefore the
level of ventilation also controls the dilution of flavoured smoke
which has passed through the flavourant with unflavoured air which
enters the smoking article through the ventilation area 69'. The
level of flavour in the smoking article can therefore be increased
or decreased.
[0108] In some aspects, the blank 60 comprises a further
ventilation area (not shown) at a location 63 on the blank
downstream of the variable ventilation arrangement 69'. The further
ventilation area comprises a plurality of discrete ventilation
areas or apertures, for example, in a circumferentially extending
line. The further ventilation area can be formed by a laser.
Generally, one or more of the ventilation areas comprise a
plurality of discrete ventilation areas or apertures. The further
ventilation area provides a constant minimum level of ventilation
which is unaffected by the variable amount of ventilation from the
ventilation area 69'. The amount of ventilation provided by the
further ventilation area can be predetermined in the manufacture of
the smoking article 10 and is, for instance, between 5% to 50% of
the volume of smoke and/or other aerosol generated by said smoking
article passing through the filter section when said variable
ventilation is at its minimum level. The variable ventilation
arrangement 69', 66 can be arranged to provide ventilation which is
user controllable within a sub-range within the range of from 0% to
90% of the volume of smoke and/or other aerosol generated by said
smoking article passing through the filter section, for instance
from 0% to 50% ventilation.
[0109] FIG. 8 illustrates schematically a method 100 of
manufacturing smoking articles according to the invention. The
method 100 comprises forming a first filter section with a first
resistance to gaseous flow or pressure drop (step 110). The first
filter section is formed from a known filtration material, for
example, cellulose acetate tow. A second filter section is
separately produced (step 120). The second filter section is also
formed from cellulose acetate tow. The resistance to gaseous flow
through the length of the second filter section is lower than the
resistance to draw through the length of the first filter section.
Optionally, the pressure drop of the second filter section is lower
than the pressure drop of the first filter section.
[0110] The different pressure drop properties of the first and
second filter sections are determined during manufacturing of the
first and second filter sections. In some aspects, the fibrous
filtration material, i.e. tow elements are configured differently
for the first and second filter sections. For example, the second
filter section is formed with a different diameter tow, compressed
more than the first filter section, different cross-section, to
obtain the different properties (i.e. lower density). The pressure
drop properties of the first and second filter sections are not
substantially changed or modified during use of the smoking
article.
[0111] In an embodiment, the second filter section is formed with
an annular cross section, to obtain a lower density. The first and
second filter sections is formed from the same fibrous filtration
material, and formed to have different cross sections in order to
obtain the different properties. In some examples, the filter
arrangement is formed of a single piece including the first filter
section and the second filter section.
[0112] The first filter section and second filter section are
assembled with one or more additional components to form the filter
arrangement of the smoking article (step 130). The first and second
filter sections may be longitudinally aligned with a source of
smokeable material. Any other known filter components can be added
to the smoking article. Examples of further filter components
include a third filter section, for instance a filter section with
particulate material (e.g. carbon, activated charcoal) or an
additional hollow section. The first and/or second filter sections
can each be considered as comprising one or more discrete filter
sections. The filter sections can be considered as generally
upstream and downstream of the variable ventilation area. The one
or more upstream filter section has a higher resistance to gaseous
flow than the one or more downstream filter section.
[0113] Wrapping material is applied to the smoking article assembly
to attach the component parts. The paper wrapping material is
tipping paper. In addition, a sleeve is wrapped around the smoking
article. The sleeve is configured to move relative to the first
filter section and, optionally, is securely attached to the second
filter section.
[0114] The smoking article is configured to allow the ingress of a
selectively variable amount of air upstream of the second filter
section. For example, ventilation apertures are formed in the
outermost layer of paper wrap and/or the paper sleeve. The
ventilation apertures are formed by a mechanical cutting tool or a
laser. The ventilation apertures are formed in the wrapping
material prior to the assembly of the smoking article (i.e.
pre-perforated apertures) or, optionally, when the smoking article
is assembled.
[0115] The ventilation has been described by entering the smoking
article upstream of the second filter section, and in particular,
into the first filter section. Alternatively, the ventilation can
be at least partially into the second filter section, e.g. adjacent
an upstream end of the second filter section. A ventilating
position for ingress of air which includes both upstream of the
second filter section and optionally an upstream part (e.g.
upstream quarter) of the second filter section is termed as located
substantially upstream of the second filter section.
[0116] The properties of the filter sections can be defined in
terms of any of: pressure drop per unit length, resistance to
gaseous flow per unit length, pressure drop, resistance to gaseous
flow, tow weight, or density. The filter sections can be defined in
terms of the filtration material having a resistance to gaseous
flow, which can be considered as independent of the length of the
filter section.
[0117] The smoking article can comprise one or more ventilation
areas providing a base level of ventilation. Such ventilation areas
(not shown) are not variable in size.
[0118] In order to address various issues and advance the art, the
entirety of this disclosure illustrates by way of illustration
various embodiments in which the claimed invention(s) may be
practiced and provide for a superior smoking article. The
advantages and features of the disclosure are of a representative
sample of embodiments only, and are not exhaustive and/or
exclusive. They are presented only to assist in understanding and
teach the claimed features. It is to be understood that advantages,
embodiments, examples, functions, features, structures, and/or
other aspects of the disclosure are not to be considered
limitations on the disclosure as defined by the claims or
limitations on equivalents to the claims, and that other
embodiments may be utilised and modifications may be made without
departing from the scope and/or spirit of the disclosure. Various
embodiments may suitably comprise, consist of, or consist
essentially of, various combinations of the disclosed elements,
components, features, parts, steps, means, etc. In addition, the
disclosure includes other inventions not presently claimed, but
which may be claimed in future.
* * * * *