U.S. patent application number 15/528294 was filed with the patent office on 2017-11-16 for apparatus and method for filter manufacture.
The applicant listed for this patent is British American Tobacco (Investments) Limited. Invention is credited to Gary FALLON, Kie Seon PARK, Sam WHIFFEN.
Application Number | 20170325496 15/528294 |
Document ID | / |
Family ID | 52292341 |
Filed Date | 2017-11-16 |
United States Patent
Application |
20170325496 |
Kind Code |
A1 |
PARK; Kie Seon ; et
al. |
November 16, 2017 |
Apparatus and Method for Filter Manufacture
Abstract
A filter rod for a smoking article comprising an extruded
hardened tubular element formed from a filter material with
entrained cured plasticiser, and a continuous core of filler
material provided within the tubular element. Also disclosed is an
apparatus for manufacturing such a filter rod, the apparatus
comprising a duct having an inlet to receive filter tow material
and plasticiser, and an outlet. The duct tapers between the inlet
and the outlet. A mandrel is disposed at least partially within the
duct and is fixed relative to the duct. The mandrel is hollow and
includes an internal passage extending though the mandrel through
which a filler material may be conveyed. The passage includes an
outlet at a distal end of the mandrel though which the filler
material may be expelled. A heating zone is configured to heat
filter material. The apparatus is configured such that filter tow
material and plasticiser conveyed through the duct is compressed
around the mandrel into a tubular rod, and filler material fed
though the internal passage of the mandrel is expelled out of the
passage outlet to fill the bore of the tubular rod. The tubular rod
is heated in the heating zone to at least partially cure the
plasticiser, to produce a continuous filter rod comprising a
tubular rod of hardened filter material with a continuous core of
filler material. Also disclosed is a method of manufacture of such
a filter rod.
Inventors: |
PARK; Kie Seon; (London,
GB) ; FALLON; Gary; (London, GB) ; WHIFFEN;
Sam; (London, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
British American Tobacco (Investments) Limited |
London |
|
GB |
|
|
Family ID: |
52292341 |
Appl. No.: |
15/528294 |
Filed: |
October 30, 2015 |
PCT Filed: |
October 30, 2015 |
PCT NO: |
PCT/GB2015/053270 |
371 Date: |
May 19, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24D 3/0279 20130101;
A24D 3/0287 20130101 |
International
Class: |
A24D 3/02 20060101
A24D003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 21, 2014 |
GB |
1420733.6 |
Claims
1. A filter rod for a smoking article wherein the filter rod
comprises a filter segment or may be cut to form individual filter
segments, and wherein the filter rod is an extruded hardened
tubular element formed from a filter material with entrained cured
plasticiser, and a continuous core of filler material provided
within the tubular element.
2. A filter rod according to claim 1 wherein the filter material
comprises cellulose acetate tow which is hardened with a
plasticiser.
3. A filter rod according to claim 1 wherein the filter rod does
not comprise any outer wrap around the tubular element.
4. A filter rod according to claim 1 wherein the filler material of
the core comprises cellulose acetate.
5. A filter rod according to claim 1 wherein the filler material
comprises a granular aerosol modifying material.
6. A filter rod according to claim 1 wherein the filler material
comprises tobacco or a derivative of tobacco.
7. A filter for a smoking article comprising a filter rod according
to claim 1, and a second filter segment axially aligned with the
filter rod and joined thereto by a plug wrap around the filter rod
and second filter segment.
8. A smoking article comprising a tobacco rod and a filter rod or
filter according to claim 1 joined to one end of the tobacco
rod.
9. An apparatus for manufacturing an extruded filter rod for
smoking articles, the apparatus comprising: a duct having an inlet
configured to receive filter tow material and plasticiser, and an
outlet, the duct tapering between the inlet and the outlet; a
mandrel disposed at least partially within the duct and fixed
relative to the duct; wherein the mandrel is hollow and includes an
internal passage extending though the mandrel through which a
filler material may be conveyed; the passage including an outlet at
a distal end of the mandrel though which the filler material may be
expelled; and a heating zone configured to heat filter material;
the apparatus configured such that filter tow material and
plasticiser conveyed through the duct is compressed around the
mandrel into a tubular rod, and filler material fed though the
internal passage of the mandrel is expelled out of the passage
outlet to fill the bore of the tubular rod, and the tubular rod is
heated in the heating zone to at least partially cure the
plasticiser, to produce a continuous filter rod comprising a
tubular rod of hardened filter material with a continuous core of
filler material.
10. An apparatus according to claim 9 wherein the internal passage
of the hollow mandrel includes a tapered section which narrows in a
direction towards the distal end of the mandrel.
11. An apparatus according to claim 9 wherein the outer dimension
of the hollow mandrel includes a tapered section which narrows in a
direction towards the distal end of the mandrel.
12. An apparatus according to claim 9 wherein a distance between an
outer surface of the mandrel and an inner surface of the duct
reduces along at least a part of the length of the duct in a
direction towards the distal end of the mandrel.
13. An apparatus according to claim 9 wherein the distal end of the
mandrel is positioned downstream of the outlet of the duct.
14. An apparatus according to claim 9 wherein the mandrel extends
entirely through the length of the duct.
15. An apparatus according to claim 9 wherein the distal end of the
mandrel is positioned within the duct.
16. An apparatus according to claim 15 wherein the mandrel extends
into the heating zone.
17. An apparatus according to claim 16, wherein the duct comprises
first and second sections, wherein the first section tapers from
the inlet to the second section, and the second section is of
constant cross-section, and wherein the distal end of the mandrel
is disposed within the second section.
18. An apparatus according to claim 15, wherein the distal end of
the mandrel is disposed within the heating zone.
19. An apparatus according to claim 9 wherein the mandrel is
disposed coaxially with the duct.
20. An apparatus according to claim 9 wherein the heating zone
comprises a steam supply to heat the filter material and
plasticiser.
21. An apparatus according to claim 20 wherein the heating zone
includes a steam chamber formed around a section of the duct, and
the duct includes steam vents to allow steam supplied to the steam
chamber to pass into the duct to directly heat the filter
material.
22. An apparatus according to claim 9 further comprising a
post-curing treatment station downstream of the heating zone with
respect to the conveyance direction of the extruded continuous
filter rod, the post-curing treatment station configured to further
smooth the outer surface of the extruded continuous filter rod.
23. An apparatus according to claim 22 wherein the post-curing
treatment station comprises an electrical heater configured to heat
the outer surface of the continuous filter rod.
24. An apparatus according to claim 23 wherein the electrical
heater is configured to heat the outer surface of the continuous
filter rod to between 100-200 degrees Celsius.
25. An apparatus according to claim 23 wherein the post-curing
treatment station is configured to melt the plasticiser on the
outer surface of the continuous filter rod so that the melted outer
surface can subsequently set as a smooth finish.
26. An apparatus according to claim 22 wherein the post-curing
treatment station comprises a spray-coating station including a
spray nozzle and a source of liquid treatment connected to the
spray nozzle to spray the liquid treatment onto the outer surface
of the continuous filter rod to form a smooth outer coating.
27. An apparatus according to claim 26 wherein the liquid treatment
sprayed from the spray nozzle comprises a plasticiser, and may
comprise triacetate.
28. An apparatus according to claim 9 further comprising a cutting
station configured to cut the continuous extruded filter rod into
discrete filter rods.
29. A method of manufacturing extruded filters for smoking
articles, the method comprising feeding filter tow material and
plasticiser into an inlet of a duct, the duct tapering between the
inlet and an outlet, conveying the filter tow material through the
duct and around a hollow mandrel disposed at least partially within
the duct and fixed relative to the duct, such that the filter
material is compressed into a tubular rod, conveying a filler
material along an internal passage extending through the hollow
mandrel, expelling the filler material from an outlet of the
internal passage at a distal end of the mandrel to fill the bore of
the tubular rod with the filler material, and heating the tubular
rod to at least partially cure the plasticiser to produce a
continuous filter rod comprising a tubular rod of hardened filter
material with a continuous core of filler material.
30. A method according to claim 29 comprising expelling the filler
material from the internal passage outlet at the distal end of the
mandrel downstream of the outlet of the duct.
31. A method according to claim 29 comprising expelling the filler
material from the internal passage outlet at the distal end of the
mandrel within the duct, upstream of the duct outlet.
32. A method according to claim 29 comprising heating the filter
material and plasticiser in a heating zone of the apparatus using
steam.
33. A method according to claim 32 comprising heating the filter
material in the heating zone to at least partially cure the
plasticiser before filling the bore of the tubular rod with the
filler material.
34. A method according to claim 29 comprising compressing the
filter tow material to at least partially form the tubular rod
before filling the bore of the tubular rod with the filler
material.
35. A method according to claim 29 comprising providing cellulose
acetate tow as the filler material.
36. A method according to claim 29 comprising providing a
pre-formed filter rod through the mandrel as the filler
material.
37. A method according to claim 29 comprising providing tobacco as
the filler material.
38. A method according to claim 29 further comprising performing a
post-curing treatment on the continuous filter rod to provide the
continuous filter rod with a smoother outer surface than the
surface texture present when expelled from the heating region.
39. A method according to claim 38 wherein the post-curing
treatment comprises heating the outer surface of the continuous
filter rod with an electrical heater and smoothing the outer
surface.
40. A method according to claim 39 wherein the post-curing
treatment comprises heating the outer surface sufficiently to melt
the plasticiser on the outer surface of the continuous filter rod
and subsequently setting the melted outer surface as a smooth
finish.
41. A method according to claim 40 comprising heating the outer
surface of the continuous filter rod to between 100-200 degrees
Celsius.
42. A method according to claim 38 wherein the post-curing
treatment comprises spray-coating a liquid treatment onto the outer
surface of the continuous filter rod to form a smooth outer
coating.
43. A method according to claim 42 comprising spraying a
plasticiser, which may comprise triacetate, onto the outer surface
of the continuous filter rod.
44. A method according to claim 29 further comprising cutting the
continuous extruded filter rod into discrete filter rods.
Description
TECHNICAL FIELD
[0001] In this specification there is described an apparatus and
method for filter manufacture and, in particular, an apparatus and
method for manufacture of filters with a filled core for use with
smoking articles.
BACKGROUND
[0002] Apparatuses and methods for manufacture of smoking article
filters are known that comprise a continuous garniture belt that
conveys filter tow material fed onto a continuous band of plug wrap
though a tapering garniture duct or "tongue". Within the garniture
tongue the garniture belt wraps the plug wrap around the filter tow
material and compresses the material into a continuous cylindrical
wrapped rod which can subsequently be cut to desired lengths.
SUMMARY
[0003] In this specification there are described embodiments of a
filter rod for a smoking article comprising an extruded hardened
tubular element formed from a filter material with entrained cured
plasticiser, and a continuous core of filler material provided
within the tubular element.
[0004] The filter material may comprise cellulose acetate tow which
is hardened with a plasticiser. The filter rod preferably does not
comprise any outer wrap around the tubular element.
[0005] The filler material of the core may comprise cellulose
acetate, and in an embodiment, may comprise a granular aerosol
modifying material. In an alternative embodiment, the filler
material may comprise tobacco or a derivative of tobacco.
[0006] The present invention also provides a filter for a smoking
article comprising a filter rod as described above, and a second
filter segment axially aligned with the filter rod and joined
thereto by a plug wrap around the filter rod and second filter
segment.
[0007] The present invention also provides a smoking article
comprising a tobacco rod and a filter rod or filter as described
above, joined to one end of the tobacco rod.
[0008] The present invention also provides an apparatus for
manufacturing an extruded filter rod for smoking articles, the
apparatus comprising a duct having an inlet configured to receive
filter tow material and plasticiser, and an outlet, the duct
tapering between the inlet and the outlet, a mandrel disposed at
least partially within the duct and fixed relative to the duct,
wherein the mandrel is hollow and includes an internal passage
extending though the mandrel through which a filler material may be
conveyed, the passage including an outlet at a distal end of the
mandrel though which the filler material may be expelled, and a
heating zone configured to heat filter material, the apparatus
configured such that filter tow material and plasticiser conveyed
through the duct is compressed around the mandrel into a tubular
rod, and filler material fed though the internal passage of the
mandrel is expelled out of the passage outlet to fill the bore of
the tubular rod, and the tubular rod is heated in the heating zone
to at least partially cure the plasticiser, to produce a continuous
filter rod comprising a tubular rod of hardened filter material
with a continuous core of filler material.
[0009] The internal passage of the hollow mandrel may include a
tapered section which narrows in a direction towards the distal end
of the mandrel.
[0010] The outer dimension of the hollow mandrel may include a
tapered section which narrows in a direction towards the distal end
of the mandrel.
[0011] A distance between an outer surface of the mandrel and an
inner surface of the duct may reduce along at least a part of the
length of the duct in a direction towards the distal end of the
mandrel.
[0012] The distal end of the mandrel may be positioned downstream
of the outlet of the duct. The mandrel may extend entirely through
the length of the duct. Alternatively, the distal end of the
mandrel may be positioned within the duct. The mandrel may extend
into the heating zone.
[0013] The duct may comprise first and second sections, wherein the
first section tapers from the inlet to the second section, and the
second section is of constant cross-section, and wherein the distal
end of the mandrel is disposed within the second section.
[0014] The distal end of the mandrel may be disposed within the
heating zone.
[0015] The mandrel may be disposed coaxially with the duct.
[0016] The heating zone may comprise a steam supply to heat the
filter material and plasticiser. The heating zone may include a
steam chamber formed around a section of the duct, and the duct may
include steam vents to allow steam supplied to the steam chamber to
pass into the duct to directly heat the filter material.
[0017] The apparatus may further comprise a post-curing treatment
station downstream of the heating zone with respect to the
conveyance direction of the extruded continuous filter rod, and the
post-curing treatment station may be configured to further smooth
the outer surface of the extruded continuous filter rod.
[0018] The post-curing treatment station may comprise an electrical
heater configured to heat the outer surface of the continuous
filter rod. The electrical heater may be configured to heat the
outer surface of the continuous filter rod to between 100-200
degrees Celsius.
[0019] The post-curing treatment station may be configured to melt
the plasticiser on the outer surface of the continuous filter rod
so that the melted outer surface can subsequently set as a smooth
finish.
[0020] The post-curing treatment station may comprise a
spray-coating station including a spray nozzle and a source of
liquid treatment connected to the spray nozzle to spray the liquid
treatment onto the outer surface of the continuous filter rod to
form a smooth outer coating. The liquid treatment sprayed from the
spray nozzle may comprise a plasticiser, and may comprise
triacetate.
[0021] The apparatus may further comprise a cutting station
configured to cut the continuous extruded filter rod into discrete
filter rods.
[0022] The present invention also provides a method of
manufacturing extruded filters for smoking articles, the method
comprising feeding filter tow material and plasticiser into an
inlet of a duct, the duct tapering between the inlet and an outlet,
conveying the filter tow material through the duct and around a
hollow mandrel disposed at least partially within the duct and
fixed relative to the duct, such that the filter material is
compressed into a tubular rod, conveying a filler material along an
internal passage extending through the hollow mandrel, expelling
the filler material from an outlet of the internal passage at a
distal end of the mandrel to fill the bore of the tubular rod with
the filler material, and heating the tubular rod to at least
partially cure the plasticiser to produce a continuous filter rod
comprising a tubular rod of hardened filter material with a
continuous core of filler material.
[0023] The method may comprise expelling the filler material from
the internal passage outlet at the distal end of the mandrel
downstream of the outlet of the duct. The method may comprise
expelling the filler material from the internal passage outlet at
the distal end of the mandrel within the duct, upstream of the duct
outlet.
[0024] The method may comprise heating the filter material and
plasticiser in a heating zone of the apparatus using steam.
[0025] The method may comprise heating the filter material in the
heating zone to at least partially cure the plasticiser before
filling the bore of the tubular rod with the filler material.
[0026] The method may comprise compressing the filter tow material
to at least partially form the tubular rod before filling the bore
of the tubular rod with the filler material.
[0027] The method may comprise providing cellulose acetate tow as
the filler material.
[0028] The method may comprise providing a pre-formed filter rod
through the mandrel as the filler material.
[0029] The method may comprise providing tobacco as the filler
material.
[0030] The method may further comprise performing a post-curing
treatment on the continuous filter rod to provide the continuous
filter rod with a smoother outer surface than the surface texture
present when expelled from the heating region.
[0031] The post-curing treatment may comprise heating the outer
surface of the continuous filter rod with an electrical heater and
smoothing the outer surface.
[0032] The post-curing treatment may comprise heating the outer
surface sufficiently to melt the plasticiser on the outer surface
of the continuous filter rod and subsequently setting the melted
outer surface as a smooth finish.
[0033] The method may comprise heating the outer surface of the
continuous filter rod to between 100-200 degrees Celsius.
[0034] The post-curing treatment may comprise spray-coating a
liquid treatment onto the outer surface of the continuous filter
rod to form a smooth outer coating, and may comprise spraying a
plasticiser, which may comprise triacetate, onto the outer surface
of the continuous filter rod.
[0035] The method may further comprise cutting the continuous
extruded filter rod into discrete filter rods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] Embodiments will now be described, by way of example only,
with reference to the accompanying drawings, in which:
[0037] FIG. 1 schematically shows a cross-section of a first
embodiment of an apparatus for manufacturing filter rods;
[0038] FIG. 2 shows an enlarged view of a first portion of the
apparatus shown circled in a dashed line in FIG. 1;
[0039] FIG. 3 shows an enlarged view of a second portion of the
apparatus shown circled in a dashed line in FIG. 1;
[0040] FIG. 4 shows a cross-section through the apparatus of FIGS.
1 and 2 along the line X-X;
[0041] FIG. 5 shows a cross-sectional view along the line Y-Y as
shown in FIG. 1, of a first embodiment of a filter rod manufactured
using the apparatus of FIG. 1;
[0042] FIG. 6 shows a first embodiment of a smoking article
including a filter made from a filter rod shown in FIG. 5;
[0043] FIG. 7 shows a cross-sectional view of a second embodiment
of a smoking article including a filter made from a filter rod
shown in FIG. 5;
[0044] FIG. 8 schematically shows a cross-section of a second
embodiment of an apparatus for manufacturing filter rods; and
[0045] FIG. 9 shows a cross-sectional view along the line Z-Z as
shown in FIG. 8, of a second embodiment of a filter rod
manufactured using the apparatus of FIG. 8.
DETAILED DESCRIPTION
[0046] Referring now to FIG. 1, an apparatus 10 of a first
embodiment is shown for the manufacture of filter rods and
comprises a duct 11 having an inlet 12 and an outlet 13. The duct
11 comprises a first section 11a that is circular in cross-section
and that narrows from the inlet 12 to an intermediate point 15, and
a second section 11b of constant circular cross-section extending
from the intermediate point 15 to the outlet 13. A source of
compressed air (shown by arrows `C`) is provided to the duct 11 via
compressed air ports 14 which, in use, helps propel filter tow
material 16 into and through the duct 11.
[0047] A mandrel 17 is disposed within the duct 11 and comprises an
elongate cylindrical member with a hollow passage 18 extending in
an axial direction through the centre of the mandrel 17. The
passage 18 includes an inlet 18a at a proximal end of the mandrel
and an outlet 18b at the opposite, distal end of the mandrel 17.
The mandrel 17 extends through both the first section 11a and
second section 11b of the duct 11. The distal end of the mandrel 17
is disposed beyond the outlet 13 of the duct 11. The mandrel 17 is
fixedly secured in the apparatus 10 so as to be fixed relative to
the duct 11.
[0048] The second section 11b of the duct 11 has a central bore 19
which is circular in cross-section, as can be seen from FIG. 4. The
cross-section of the bore 19 of the second section 11b of the duct
11 is constant along its length.
[0049] A heating zone 20 is provided in combination with and around
a portion of the second duct section 11b. The heating zone 20
comprises a closed chamber 21 around the second duct section 11b
with steam inlets 22. The second duct section 11b includes a
plurality of steam vents 23 which, in use, allow steam provided to
the chamber 21 to pass into the bore 19 of the second duct section
11b. A source of dry steam (not shown) is connected to the steam
inlets 22 to supply hot dry steam to the chamber 21.
[0050] A cutting station 24 is provided downstream of the outlet 13
of the duct 11 and includes a cutting blade 25.
[0051] In use, filter tow material 16, such as cellulose acetate
tow mixed with a plasticiser, is fed into the inlet 12 of the duct
11. The filter material 16 is mixed with the plasticiser, such as
triacetate, in a ratio of about 17% by weight, although other
ratios of plasticiser may be used within the scope of the
invention, such as between 4% and 50% by weight. The filter tow
with entrained plasticiser is conveyed through the first duct
section 11a using jets of compressed air provided through the
compressed air ports 14. The tow material 16 passes around the
mandrel 17 and is compressed into a cylindrical filter rod 26 as it
passes through the tapering first duct section 11a. The tow
material 16 is formed around the mandrel 17 and is thereby
compressed into a tubular filter rod 26 with a hollow core.
Simultaneously, a filler material 27 is fed into the open end 18a
of the passage 18 of the mandrel 17 and is conveyed through the
passage 18. This filter rod 26 being formed of the filter tow
material 16 compressed around the mandrel 17 containing the filler
material 27 is shown in cross-section in FIG. 4.
[0052] As the tubular filter rod 26 passes through the second duct
section 11b around the mandrel 17, dry steam at around 170 degrees
Celsius is supplied to the chamber 21 and passes through the steam
vents 23 and into the filter rod 26. The steam permeates and heats
the filter rod 26. The filter rod 26 is also heated by being in
contact with the second duct section 11b which itself is heated by
the steam. The supplied heat cures or substantially cures the
entrained plasticiser in the filter tow material 16 so that the
continuous filter rod 26 hardens to form a stiff continuous filter
rod. The hardened continuous filter rod exits the heating zone 20
and exits the duct 11 through the outlet 13.
[0053] The filler material 27 is conveyed through the passage 18 in
the mandrel 17 and is expelled out of the outlet 18b into the
hollow core of the filter rod 26. This results in a hardened
continuous filter rod 28 with a continuous core of filler material
27
[0054] After the hardened continuous filter rod 28 exits the outlet
13 of the duct 11, it passes to the cutting station 24 where the
cutting blade 25 cuts the hardened continuous filter rod 28 into
individual lengths of discrete filter rods 29 having a continuous
core filled with the filler material 27. These may be single length
filter rods 29 of a size suitable for use in combination with a
single tobacco rod to make a single smoking article. Alternatively,
the discrete filled-core filter rods 29 may be "2-up", "4-up" rods,
or other lengths which are a multiple of a single length filter
that would be joined to a tobacco rod in a finished smoking
article. Such multiple length filters can be supplied to subsequent
smoking article manufacturing machinery to be cut to length in
later processing steps.
[0055] A discrete core-filled filter rod 29 of the invention
manufactured using the above-described apparatus and method is
shown in cross-section in FIG. 5. The filter rod 29 is
substantially cylindrical and is continuous in cross-section along
its length. The filter rod 29 comprises an outer tubular section 30
of hardened tow material 16, and core 31 of the filler material
27.
[0056] The core-filled filter rods 29 manufactured using the
above-described apparatus and method are sufficiently stiff and
strong not to require any outer plug wrap layer to be applied to
maintain their shape and structural integrity. As such, the filter
rods 29 can be provided directly to a subsequent smoking article
manufacturing process and the absence of requiring an outer plug
wrap means the manufacturing process is simpler, quicker, more
efficient and more cost effective than known filter manufacturing
processes where a subsequent filter rod wrapping step is performed,
which requires additional machinery and materials. The filter rods
29 are also able to be manufactured to be accurately symmetrical
about their central axis, that is, accurately circular in
cross-section. This is at least in part because any oval distortion
which may be caused by overlapping plug wrap seams of known wrapped
filters is avoided.
[0057] FIG. 6 shows one exemplary configuration of a smoking
article 40 incorporating a discrete filter rod 29 as described
above. (Although, as described above, in a smoking article the
filter segment may be a section cut from a multiple length filter
rod 29, the filter rod segment within the smoking article 40 will
be referred to herein as "filter rod 29"). The smoking article 40
comprises a tobacco rod 41 with a filter rod 29 abutting one end of
the tobacco rod 41 and joined thereto by a tipping wrapper 42 which
overlies the join between the tobacco rod 41 and the filter rod 29.
In the exemplary smoking article 40, ventilation holes 43 are
provided to allow ambient air to be drawn into the filter rod 29
for increased ventilation as a user draws on the smoking article 40
in use. Also in the exemplary smoking article 40, the core 31 is
visible at the end of the smoking article 40. This can provide a
visual indicator to a consumer of the type of smoking article 40
and its associated filter performance and/or flavour.
[0058] In one embodiment, the filler material 27 fed into the inlet
18a of the passage 18 of the mandrel 17 may be a loose filter tow
material, such as cellulose acetate. The loose tow material may be
conveyed under pressure or force through the passage 18, and/or may
be pulled through the mandrel 17 by conveyance of the downstream
outer filter material 16 with which it is encircled. The passage 18
may be configured to taper towards the outlet 18b, such that the
tow material is compressed as it is conveyed through the passage
18. The core 31 of the resulting continuous filter rod 28 thereby
may comprise a compressed filter tow material. The filter tow
material comprising the filler material 27 may comprise an
entrained plasticiser, which may comprise triacetate, and which may
be in the proportions by weight mentioned above. However, different
proportions may be used. In particular, a lower proportion of
plasticiser may be used in the filler material such that the core
31 of the filter rods 29 are softer and more permeable to smoke
drawn through the filter rod 19 than the outer tubular section
30.
[0059] The mandrel 17 extending entirely through the duct 11 may
advantageously enable curing or part-curing of the filter tow
material 16 within the duct 11 without the heat affecting the
filler material 27 within the passage 18 of the mandrel 17. Also,
the tubular filter rod 26 may be at least partially hardened before
the filler material 27 is introduced into its hollow core. However,
the invention is not intended to be limited to the embodiment shown
in which the mandrel 17 extends entirely through the duct 11. In an
alternative embodiment, the distal end of the mandrel 17 may be
disposed within the duct 11 upstream of the outlet 13. In such an
embodiment, the filler material 27 would be expelled into the
hollow core of the tubular filter rod 26 within the duct 11. The
distal end of the mandrel 17 may be disposed within the heating
zone 20, or may be disposed downstream of the heating zone 20 but
upstream of the outlet 13 of the duct 11.
[0060] The core filler material 27 being fed under pressure and/or
being a compressed material, may advantageously facilitate
formation of the continuous filter rod 26 into a desired shape.
This results from the compressed filler material 27 exerting an
outward force on the surrounding filter tow material 16 that forms
the outer tubular section 30. In particular in the alternative
embodiment described above in which the distal end of the mandrel
17 is disposed within the duct 11, this force helps press the
filter tow material 16 against the inner wall of the bore 19 of the
second duct section 11b and so encourages the filter tow material
16 to harden in close conformity with the inner wall of the duct
11. This also helps press flat the fibres of the filter tow
material 16 on the outer surface of the continuous filter rod 26,
helping improve the roundness and smoothness of the resulting
hardened filter rods 29.
[0061] In an alternative embodiment of the invention, the filler
material 27 may be a smoke modifying material and may comprise, for
example, a granular material such as flavourant or activated
charcoal. These could be provided exclusively as the filler
material 27 or may be entrained in a carrier material, for example,
entrained in cellulose acetate tow. Furthermore, the filler
material 27 may include an entrained flavourant. The flavourant may
be provided as a solid particulate material such as flavourant
granules, or may be provided as a liquid absorbed into a carrier
material such as cellulose acetate tow.
[0062] In any of the above-described embodiments of the invention,
if the filler material 27 comprises a filter material such as
cellulose acetate tow, the tow of the filler material 27 may be the
same composition than the tow of the filter material 16 that forms
the outer tubular section 30 or may be of a different composition.
If the filler material 27 is a cellulose acetate tow of a different
composition, this may provide the core 31 with a different
filtering characteristic to the outer tubular section 30. For
example, the core 31 may have a greater or lesser draw resistance
than the outer tubular section 30. The relative draw resistance of
the core 31 and outer tubular section 30 may be chosen to control
the amount of smoke that, in use, is drawn through each part of the
filter rod 29. For example, if the core 31 has a lower draw
resistance than the outer tubular section 30, a larger proportion
of the smoke stream may flow through the core 31 than through the
outer tubular section 30. This proportion can thereby be controlled
to determine, for example, the amount of flavourant that may be
entrained in the smoke stream, or the proportion of the smoke
stream that passes over activated charcoal granules. An increased
level of plasticiser and hardening of the outer tubular section 30
can give an increased draw resistance to the outer tubular section
than that of the inner core 31.
[0063] In an exemplary embodiment, the outer tubular section 30 may
comprise cellulose acetate with 10-20% plasticiser by weight, and
the core may comprise cellulose acetate with plasticiser in 3-8% by
weight.
[0064] The outer tubular section 30 being hardened provides smoking
articles 40, 50 with structural strength during smoking by a
consumer. This can help avoid deformation of the filter during
smoking, and also provide tactile resistance to any "chewing"
action of the consumer on the filter during smoking.
[0065] In an alternative embodiment of the invention, the filler
material 27 may comprise tobacco or reconstituted tobacco. The
tobacco filler material may thereby impart a tobacco flavour to the
proportion of the smoke stream that passes through the core 31 of
the filter rod 29.
[0066] In a further embodiment of the invention, the filler
material 27 may be coloured and thereby may contrast with the
filter tow material 16 of the outer tubular section 30. This may
provide a user with a visual indicator of the filter and/or flavour
properties of the filter rod 29. For example, a filler material 27
with a menthol flavour may be coloured green. Furthermore, a range
of smoking articles may be provided that offer a range of smoking
properties, for example differing filtering properties of flavour
types or strengths. The core 31 of the filter rods 29 of such
various different smoking articles may be coloured in different
shades of a particular colour, or different colours, to indicate
said different properties. Coloured filler material 27 of the core
31 may also reduce colouring of the filler material 27 during
smoking of the smoking articles 40, 50, by disguising or at least
partially concealing discolouration caused by smoke constituents
entrained in the smoke drawn through and retained by the filter.
This may be advantageous in an embodiment in which the draw
resistance of the core 31 is lower than the draw resistance of the
outer tubular section 30, such that a major proportion of the smoke
drawn through the filter is drawn through the core 31.
[0067] In the smoking article 40 described above, a single discrete
filter rod 29 is provided abutting the tobacco rod 41 and so the
core 31 of the filter rod 29 is visible at the mouth-end of the
smoking article 40. The may provide the advantages described above.
However, alternative embodiments of smoking articles are envisaged
incorporating the above-described core-filled filters. Such smoking
articles may include multi-segment filters. A second embodiment of
smoking article 50 is shown in cross-section in FIG. 7. Like
features with the first embodiment of smoking article 40 retain the
same reference numerals. The smoking article 50 of the second
embodiment comprises a multi-segment filter 51 which comprises a
first filter segment 29 as per the filter rod 29 described above,
and a second filter segment 52 adjacent the first filter segment.
The second filter segment 52 comprises a plug of a material such as
cellulose acetate, preferably without an entrained particulate
additive or core of different filler material.
[0068] A plug wrap 53 extends around the first and second filter
segments 29, 52. The filter 51 is joined to a tobacco rod 41 by a
tipping wrapper 42. The filter 51 is arranged such that the second
filter segment 52 is disposed at the mouth-end of the smoking
article, and the first filter segment 29 is disposed between the
second filter segment 52 and the tobacco rod 41. The smoking
article 50 of the second embodiment may be advantageous in the case
where the core 31 of the first filter segment 29 comprises a
particulate material, either entrained in a carrier material as
described above, or exclusively as the core material. For example,
if the core 31 comprises tobacco or charcoal granules entrained in
cellulose acetate tow. In such case, the second filter segment 52
prevents the particulate material from coming out of the core 31 of
the first filter segment 29 and into a user's mouth when a user
draws on the smoking article 50 in use. It may also provide the
mouth-end of the smoking article 50 with a conventional appearance,
namely a filter end with a plain end face of continuous filter
material. This may be beneficial to enable provision of improved
filtering and/or flavour delivery functions using a core-filled
filter as described above, without presenting the consumer with a
visually different smoking article to that of their regular
preferred smoking articles.
[0069] An apparatus 110 of a second embodiment is shown in FIG. 8
and is similar to the apparatus 10 of the first embodiment. Like
features between apparatuses 10, 110 of the first and second
embodiments retain the same reference numerals and detailed
description will not be repeated. A difference with the apparatus
110 of the second embodiment is that the apparatus 110 includes a
post-curing treatment station 111 disposed downstream of the
heating zone 20, with respect to the conveyance direction of the
continuous filter rod 26. The post-curing treatment station 111 is
disposed upstream of the cutting station 24.
[0070] The post-curing treatment station 111 is provided to yet
further smooth the outer surface of the continuous filter rod 26
after it has been formed in the second duct section 11b and
hardened at the heating zone 20. The filter tow material 16 used to
produce the filter rods 29 may comprise many discrete filaments
tangled together. Upon formation of the hardened continuous filter
rod 28 in the apparatus of the first embodiment, some ends of the
filaments may remain upstanding from the outer surface of the
filter rod 28 and appear as fine upstanding "hairs". The
post-curing treatment station 111 is therefore intended to provide
a further treatment to the continuous filter rod 28 to eliminate
these hairs and to give the final discrete filter rods 29 a
smoother outer finish.
[0071] The post-curing treatment station 111 comprises central
passage 112 and electrical heater elements 113. The central passage
112 may be continuous with the duct 11 so that the continuous
filter rod 26 passes straight from the outlet 13 of the duct 11
into the central passage 112 of the post-curing treatment station
111.
[0072] In use, as the continuous filter rod 26 passes from the
outlet 13 of the duct 11, having passed though the heating zone 20
and cured or at least partially cured, it passes into the
post-curing treatment station 111. The electrical heating elements
113 heat the filter rod 26 such that the tow material and
plasticiser of the outermost surface of the filter rod 26 melts.
This also causes any fine hairs upstanding on the outermost surface
of the filter rod 26 to also melt. As the hardened filter rod with
filled core 28 exits the post-curing treatment station 111, the
melted outer surface cools and hardens, forming a thin and smooth
outer coating around the continuous filter rod 28.
[0073] Following the post-curing treatment station 111, the filter
rod 28 is cut into discrete filter rods 129 at a cutting station 24
as per the first embodiment of the apparatus 10 described
previously.
[0074] FIG. 9 shows a cross-section of the second embodiment of
filter rod 129 along the line Z-Z shown in FIG. 8. As with the
filter rods 29 of the first embodiment, the filter rods 129 of the
second embodiment comprise an outer tubular section 30 with a
continuous core 31 of filler material 27. However, the filter rods
129 also include a thin smooth outer coating 130 formed by the
melted and hardened tow and plasticiser as described above.
[0075] The apparatus of the second embodiment 110 is configured
with the conveyance speed of the filter rod 26 and the power of the
heating elements 113 such that only a thin outer surface of the
filter rod 26 is melted in the post-curing treatment station 111
and heat does not permeate far though the thickness of the filter
rod 26. This leaves the majority of the body of the filter rod 26
unaffected by the post-curing treatment. The heating process
preferably heats the filter rod 27 to between 100-200 degrees
Celsius. This range is optimum for being sufficiently hot to
achieve melting of the plasticiser and tow, but not excessively hot
as to overheat the filter rod 26 which could cause the material
within the body of the filter rod to melt rather than just melt a
thin outer layer, which would result in the filter being unusable
as the internal melting of the filter rod 26 would render it
impermeable.
[0076] An apparatus of an alternative embodiment (not shown) may
comprise a different configuration of post-curing treatment station
111 disposed downstream of the heating zone 20 and upstream of the
cutting station 24. Such alternative configuration of post-curing
treatment station may still be provided to smooth the outer surface
of the continuous grooved filter rod 26. However, instead of
including heating elements to heat and melt the outer surface of
the continuous filter rod 26, the post-curing treatment station may
comprise one or more spray nozzles within a chamber through which
the continuous filter rod 26 is conveyed. In use, the spray nozzles
may spray the outer surface of the continuous filter rod 26 with a
liquid coating which may harden to form a thin and smooth layer
around the continuous filter rod 26. The liquid coating may
comprise a plasticiser and may comprise triacetate. Alternatively,
the coating may comprise a liquid polymer, such as, polypropylene.
Following the alternative configuration of post-curing treatment
station, the continuous filter rod 26 may be cut into discrete
filter rods at a cutting station as per the first and second
embodiments of the apparatus 10, 110 described previously. Such
resulting filter rods may be as per the filter rod 129 shown in
FIG. 9, having the smooth outer coating 130.
[0077] In the apparatus 110 of the second embodiment, the
electrical heating elements 113 are described as heating the filter
rod 26 such that the tow material and plasticiser of the outermost
surface of the filter rod 26 melts, and/or also melting any fine
hairs upstanding on the outermost surface of the filter rod 26.
However, the invention is not limited to this configuration and
method of operation, and the apparatus no may be configured and
operated such that the heating elements 113 do not appreciably melt
the plasticiser in the outer surface of the filter rod 26, but only
soften and physically flatten any upstanding hairs on the filter
rod, acting with an "ironing" effect. In such a method of
operation, there would not be an appreciable solidified coating
formed on the outer surface of the filter rod 26 by melted and
hardened tow and plasticiser. However, the final filter would have
a smoothed outer surface. In such a method of operation, the
temperature of the heating elements 113 may be controlled to be
below a temperature that would melt the plasticiser in the filter
rod 26, for a given conveyance speed of the filter rod 26 though
the post-curing treatment station 111.
[0078] In the apparatus 10 of the first embodiment described above,
the distal end of the mandrel 17 is disposed downstream of the
outlet 13 of the duct 11. This arrangement may advantageously
promote the formation of a constant cross-section of filter rod 29
described above. This may result from the filler material 27 only
being introduced into the core of the outer tubular section 30 of
the filter rod 26 once the duct 11 has reached it narrowest point,
so that the filter material 16 of the outer tubular section 30 is
fully compressed before the filler material 27 is introduced. Also,
in the alternative embodiment in which the distal end of the
mandrel 17 is disposed within the duct 11, any outward pressure
exerted by the filler material 27 therefore acts upon the
compressed filter material 16. However, the invention is not
limited to this configuration and the mandrel may alternatively
terminate with the distal end in the first, tapering section 11a of
the duct 11.
[0079] The post-curing treatment station in of the apparatus 110 of
the second embodiment may be formed integrally with the duct 11 or
alternatively may be a separate apparatus to the duct 11, and
positioned in abutment with the duct 11 so that the continuous
filter rod 26 passes directly from the outlet 13 of the duct 11
into the central passage 112 of the post-curing treatment station
111. Yet further, within the scope of the invention, the post
curing treatment station 111 may be spaced from the outlet 13 of
the duct 11 so the continuous filter rod 26 does not pass
immediately into the central passage 112 of the post-curing
treatment station after leaving the outlet 13 of the duct 11.
[0080] The apparatuses 10, 110 and the methods for filter
manufacture avoids use of a conventional garniture belt and plug
wrap, thereby avoiding the added complexity and materials of
conventional filter road manufacture and therefore the associated
costs. Also, a continuous core of filler material is provided in
the filter rods 29, 129 in a process that enables high-speed
production. Such apparatuses 10, 110 also avoid the need for
complex moving mechanisms such as those that may be required in the
manufacture of other types of filter which have spaced elements
within the filter core. Such mechanisms which may intermittently
insert capsules or other elements at regular spacing within a
filter core are complex and may require complex control systems to
remain accurately in register to ensure the filters produced are
consistent and have core elements inserted at the correct spacing.
Such mechanisms are therefore costly to produce and maintain.
[0081] In the apparatuses 10, 110 described above, the heating zone
20 formed around a section of the duct 11. This may advantageously
allow for a compact apparatus configuration. However, the invention
is not intended to be limited to such a configuration and in an
alternative embodiment, the heating zone 20 may be provided at a
separate duct section into which the compressed and extruded
continuous filter rod 26 is fed. This latter alternative
configuration may advantageously facilitate maintenance of the
apparatus, as the heating zone may be separable from the duct
section in which the filter material is compressed into a
continuous filter rod, enabling easier access and cleaning.
[0082] The mandrel 17 may include means to facilitate the filler
material 27 being conveyed though the passage 18 from the inlet 18a
to the outlet 18b. Such means may comprise a compressed air supply
coupled to the mandrel 17 to pass compressed air through the
passage together with the filler material 27 in a similar manner to
how the loose filter tow material 16 is conveyed through the duct
11. The mandrel 17 may include one or more compressed air ports
(not shown) extending through a side wall thereof for the supply of
compressed air into the passage 18. However, the invention is not
limited to such a configuration and the filler material 27 may be
drawn through the mandrel 17 by being entrained in the filter tow
material 16 conveyed through the duct 11.
[0083] The passage 18 of the mandrel 17 is shown as tapering to
narrow between the inlet 18a and the outlet 18b. However, the
invention is not intended to be limited to such a configuration and
the passage 18 within the mandrel 17, may be of a constant
cross-section along its length.
[0084] Furthermore, the outer surface of the mandrel 17 is shown as
narrowing from the inlet 18a end. However, the invention is not
limited to such a configuration and the mandrel 17 may be of a
constant cross-section along its length.
[0085] An advantageous configuration of the apparatuses 10, 110 of
the invention comprises the duct 11 tapering to narrow along at
least part of the length of the mandrel 17. That is, the distance
between the outer surface of the mandrel 17 and the inner surface
of the duct 11 reduces along at least a part of the length of the
duct 11 in a conveyance direction of the filter tow material 16.
This helps compress and at least partially form the filter tow
material 16 into the hollow tubular section 30 before introduction
of the filler material 27 from within the passage 18 of the mandrel
17.
[0086] The apparatuses 10, 110 and methods of the invention
described above comprise filler material 27 being introduced into a
hollow core of the outer tubular section 30. Although the filler
material 27 may be loose, such as a fibrous tow or a granular
material, the invention is not intended to be limited to such
filler material 27. It is intended in an embodiment of the
invention that the filler material 27 may comprise a pre-formed
slim continuous filter rod to form the core 31 of the discrete
filter rods 29, 129. The filter tow material 16 would then be
formed around the pre-formed slim filter rod. Such pre-formed
filter rods used as the filler material 27 may be of a size as in
known super-slim smoking articles. In such an embodiment, the
pre-formed slim filter rod could be conveyed through the apparatus
10, 110 by being pulled though by the conveyance of the surrounding
filter tow material 16. In all embodiments, the continuous filter
rods 28 may be pulled through the duct 11 by down-stream conveyance
drivers (not shown) such as one or more driven rollers, wheels or
belts.
[0087] An advantageous configuration of the apparatus 10, 110 and
method of the invention, and filter rods 29, 129 formed thereby, is
that the core 31 and outer tubular section 30 are each formed of a
generally homogenous material although each are separate materials.
That is, the material of the core 31 is not mixed or blended with
the material of the outer tubular section 30 and a clear boundary
exists between each part of the filter rod 29, 129. As well as
providing a distinctive and clean appearance, this also allows
accurate control of the filtering characteristics and performance
of the filter rods 29, 129 of the invention. This may
advantageously be facilitated by curing or at least part curing of
the filter tow material 16 before introduction of the filler
material into the core of the tubular filter rod 26. This may be
achieved by the distal end of the mandrel 17 being disposed within
or downstream of the heating zone 20.
[0088] In embodiments of the apparatuses 10, 110 of the invention,
the mandrel 17 extends into the heating zone 20. That is, the
distal end of the mandrel 17 may be disposed within or downstream
of the heating zone 20. For example, the mandrel 17 may extend into
the region of the duct 11 within the steam chamber 21 and/or at or
beyond at least one of the steam vents 23 formed in the duct 11.
This may advantageously enable at least partial curing of the
filter tow material 16 forming the outer tubular section 30 before
introduction of the filler material 27. This may advantageously
help avoid collapse of the outer tubular section 30 during
formation. The mandrel 17 extending entirely through the heating
zone may advantageously enable improved hardening of the outer
tubular section 30 around the mandrel before introduction of the
filler material 27 and so provide improved circularity of the core
31.
[0089] The apparatuses 10, 110 and methods of the invention
described above comprise dry steam at around 170 degrees Celsius
being supplied to the chamber 21 to pass through the steam vents 23
and into the filter rod 26. However, the invention is not limited
to this specific temperature and the temperature of the dry steam
may vary within the scope of the invention. For example, between
100-200 degrees Celsius, and may be between 120-190 degrees
Celsius, and may be between 150-180 degrees Celsius. Furthermore,
the temperature of the steam may be selected proportional to the
amount of plasticiser entrained in the filter tow material 16
and/or also the conveyance speed of the filter tow material 16
through the duct 11.
[0090] In an advantageous configuration of the apparatus 10, 110 of
the invention, the duct 11 and mandrel 17 are elongate and comprise
respective central axes, and the duct 11 and mandrel 17 are
co-axial. This may advantageously enable formation of symmetrical
and uniform filter rods 29, 129.
[0091] In the second embodiment of smoking article 50 described
above, the multi-segment filter 51 includes a plug wrap 53
extending around the first and second filter segments 29, 52. This
advantageously aids manufacturing as the multi-segment filter may
be assembled prior to a separate step in which it is joined to a
tobacco rod to make the smoking article. Also, multiple-lengths of
multi-segment filters may be produced (e.g. 2-up or 4-up rods) with
the filter segments joined by a plug wrap, before being combined
with tobacco rods in a separate assembly step to produce smoking
articles. However, the invention is not intended to be limited to
such a configuration of smoking article, and it is intended that
the first and second filter segments 29, 52 may be axially aligned
and joined together and to the tobacco rod 41 by the tipping
wrapper 42 alone, without also including a plug wrap. This latter
configuration may advantageously reduce the number of smoking
article assembly steps by the tobacco rod, and first and second
filter segments all being combined together with a tipping wrapper
in a single assembly process.
[0092] As used herein, the term "smoking article" includes
smokeable products such as cigarettes, cigars and cigarillos
whether based on tobacco, tobacco derivatives, expanded tobacco,
reconstituted tobacco or tobacco substitutes and also heat-not-burn
products and other nicotine delivery product such as aerosol
generation devices including e-cigarettes. The smoking article may
be provided with a filter for the gaseous flow drawn by the smoker.
In embodiments intended for use with heat-not-burn products and
other nicotine delivery products, reference in the description
above to "smoke" and "smoke modifying material" should be construed
as encompassing other aerosols and inhalants other than smoke and
the products of combustion of a material.
[0093] In order to address various issues and advance the art, the
entirety of this disclosure shows by way of illustration various
embodiments in which the claimed invention(s) may be practiced and
provide for superior filters, and apparatuses and methods for
manufacture of filters. 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.
* * * * *