Method and apparatus for manufacturing filters for smoking articles

Abstract

There is provided a method and apparatus for manufacturing filters for smoking articles. The method comprises providing hollow tubes (309) of filter material. Each hollow tube has an outer diameter and an inner diameter. The method further comprises providing filter inserts (205). Each filter insert (205) has a first portion having a cross sectional dimension larger than the inner diameter of the hollow tube. The method further comprises inserting each filter insert (205) into a hollow tube (309) of filter material. During inserting, the first portion of the filter insert (205) engages with the hollow tube (309) to retain the filter insert in the hollow tube.

Claims

1. A method for manufacturing filters for smoking articles, the method comprising the steps of: providing hollow tubes of filter material, each hollow tube having an outer diameter and an inner diameter; providing filter inserts, each filter insert having a first portion having a cross sectional dimension larger than the inner diameter of the hollow tubes; and inserting each filter insert into a hollow tube of filter material, wherein the step of inserting comprises positioning each filter insert relative to a hollow tube of filter material by positioning each filter insert within a sleeve or sleeves adjacent a hollow tube of filter material such that, during inserting, the first portion of the filter insert engages with the hollow tube to retain the filter insert in the hollow tube, wherein the filter insert is substantially spherical, the cross sectional dimension of the first portion of the filter insert being a diameter of the substantially spherical filter insert.

2. A method according to claim 1, wherein the step of inserting comprises inserting two filter inserts simultaneously into each hollow tube of filter material, the two filter inserts being inserted from opposite ends of the hollow tube of filter material.

3. A method according to claim 1, wherein each filter insert has a second portion having a cross sectional dimension smaller than the inner diameter of the hollow tube, and wherein, during the step of inserting, the second portion of the filter insert is the leading portion.

4. A method according to claim 1, wherein each hollow tube of filter material comprises a filter wrapper circumscribing the filter material.

5. A method according to claim 1, wherein the step of inserting each filter insert into the hollow tube of filter material comprises supporting the hollow tube of filter material on a first rotatable drum.

6. A method according to claim 5, wherein supporting the hollow tube of filter material on the first rotatable drum comprises providing a pressure difference between the inside and the outside of the first drum such that the hollow tube of filter material adheres to the drum.

7. A method according to claim 5, wherein the first rotatable drum is rotating continuously during the step of inserting the filter insert into the hollow tube of filter material.

8. Apparatus for manufacturing filters for smoking articles, each filter comprising a hollow tube of filter material, the hollow tube having an outer diameter and an inner diameter, and first and second filter inserts disposed in the hollow tube of filter material, each of the first and second filter inserts having a first portion having a cross sectional dimension larger than the inner diameter of the hollow tube, the apparatus comprising: a first piston configured to engage and push the first filter insert into the hollow tube of filter material such that, during inserting, the first portion of the first filter insert engages with the hollow tube to retain the first filter insert in the hollow tube; a second piston configured to engage and push the second filter insert into the hollow tube of filter material such that, during inserting, the first portion of the second filter insert engages with the hollow tube to retain the second filter insert in the hollow tube, wherein the first and second pistons are arranged to insert the first and second filter inserts from opposite ends of the hollow tube of filter material, wherein the apparatus is configured to cause the first and second pistons to insert the first and second filter inserts simultaneously into the hollow tube of filter material; a first sleeve configured to receive the first filter inserts, wherein the first sleeve is positionable relative to the hollow tube of filter material such that actuation of the first piston causes the first filter insert to be pushed from within the first sleeve into the hollow tube of filter material; and a second sleeve configured to receive the second filter insert, wherein the second sleeve is positionable relative to the hollow tube of filter material such that actuation of the second piston causes the second filter insert to be pushed from within the second sleeve into the hollow tube of filter material.

9. Apparatus according to claim 8, wherein each of the first and second filter inserts have a second portion having a cross sectional dimension smaller than the inner diameter of the hollow tube, and wherein the apparatus is configured to cause the first and second pistons to insert the first and second filter inserts into the hollow tube such that the second portion of each of the first and second filter inserts are the leading portion during the inserting.

10. Apparatus according to claim 8, wherein the filter insert is substantially spherical, the cross sectional dimension of the first portion of each of the first and second filter inserts are a diameter of the substantially spherical filter insert.

11. Apparatus according to claim 8, wherein the hollow tube of filter material comprises a filter wrapper circumscribing the filter material.

12. Apparatus according to claim 8, further comprising a first rotatable drum for supporting the hollow tube of filter material as the first and second filter inserts are inserted into the hollow tubes of filter material.

13. Apparatus according to claim 8, further comprising a hopper configured to deliver the first and second filter inserts relative to the first and second pistons.

14. Apparatus according to claim 8, wherein the first and second sleeves are positionable adjacent a hollow tube of filter material.

15. Apparatus according to claim 8 further comprising: first rotatable drum for supporting the hollow tube of filter material as the first and second filter inserts are inserted into the hollow tube of filter material; and a hopper configured to deliver the first and second filter inserts relative to the first and second pistons.

16. Apparatus for manufacturing filters for smoking articles, each filter comprising a hollow tube of filter material, the hollow tube having an outer diameter and an inner diameter, and first and second filter inserts disposed in the hollow tube of filter material, each of the first and second filter inserts having a first portion having a cross sectional dimension larger than the inner diameter of the hollow tube, the apparatus comprising: a first piston configured to engage and push the first filter insert into the hollow tube of filter material such that, during inserting, the first portion of the first filter insert engages with the hollow tube to retain the filter insert in the hollow tube; a second piston configured to engage and push the second filter insert into the hollow tube of filter material such that, during inserting, the first portion of the second filter insert engages with the hollow tube to retain the second filter insert in the hollow tube, wherein the first and second pistons are arranged to insert the first and second filter inserts from opposite ends of the hollow tube of filter material, wherein the apparatus is configured to cause the first and second pistons to insert two filter inserts simultaneously into the hollow tube of filter material a first sleeve configured to receive the first filter insert, wherein the first sleeve is positionable relative to the hollow tube of filter material such that actuation of the first piston causes the first filter insert to be pushed from within the first sleeve into the hollow tube of filter material, a second sleeve configured to receive the second filter insert, wherein the second sleeve is positionable relative to the hollow tube of filter material such that actuation of the second piston causes the second filter insert to be pushed from within the second sleeve into the hollow tube of filter material; and a hopper configured to deliver the first and second filter inserts relative to the first and second sleeves.

17. Apparatus according to claim 16 further comprising a first rotatable drum for supporting the hollow tube of filter material as the first and second filter inserts are inserted into the hollow tubes of filter material.

18. Apparatus according to claim 16, wherein the first and second sleeves are positionable adjacent the hollow tube of filter material for positioning the first and second filter inserts relative to the hollow tube of filter material.

Description

(1) The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

(2) FIG. 1 is a perspective view of a smoking article including a filter manufactured according to an embodiment of the invention;

(3) FIG. 2 is a cross sectional view of a filter manufactured according to an embodiment of the invention;

(4) FIG. 3 is a cross sectional view of apparatus for manufacturing filters according to an embodiment of the invention;

(5) FIG. 4 is a perspective view of the operating drum of FIG. 3;

(6) FIG. 5 is a view of the inserting means of FIGS. 3 and 4 in a first position; and

(7) FIG. 6 is view of the inserting means of FIGS. 3 and 4 in a second position.

(8) FIG. 1 is a perspective view of a smoking article 100 including a filter manufactured according to one embodiment of the invention. The smoking article 100 includes a generally cylindrical tobacco rod 101 and a generally cylindrical filter 103. The tobacco rod 101 and filter 103 are axially aligned in an end-to-end relationship, preferably abutting one another.

(9) The tobacco rod includes an outer wrapper 105 circumscribing the smoking material. The outer wrapper 105 may be a porous wrapping material or paper wrapper. The tobacco is preferably a shredded tobacco or tobacco cut filler. The tobacco rod 101 has an upstream, lit end 107 and a downstream end 109. The filter 103 has an upstream end 111 and a downstream, mouth end 113. The upstream end 111 of the filter 103 is adjacent the downstream end 109 of the tobacco rod 101. Although not visible in FIG. 1, a filter insert is disposed in the filter 103.

(10) The filter 103 is attached to the tobacco rod 101 by tipping material 115 which circumscribes the entire length of the filter 103 and an adjacent region of the tobacco rod 101. The tipping material 115 is shown partially removed from the smoking article in FIG. 1, for clarity. The tipping material 115 is typically a paper like product. However, any suitable material can be used. In this embodiment, the tipping material 115 includes a circumferential row of perforations 117 aligned with the filter 103. The perforations are provided for ventilation of the mainstream smoke.

(11) In this specification, the upstream and downstream relative positions between smoking article components are described in relation to the direction of mainstream smoke as it is drawn from the tobacco rod 101 and through the filter 103.

(12) FIG. 2 is a cross sectional view of a filter 103 manufactured according to one embodiment of the invention. The filter 103 may be used in the smoking article of FIG. 1. In FIG. 2, the filter 103 comprises a hollow tube 201 of filter material 203. The hollow tube 201 has an outer diameter 207 and an inner diameter 209. The filter 103 further comprises a filter insert in the form of flow restricting bead 205. The flow restricting bead 205 may comprise air-impermeable material. The flow restricting bead 205 is substantially spherical, with a diameter 211 and a leading cross-sectional dimension 213. The flow restricting bead 205 is disposed in the hollow tube 201. Diameter 211 of the flow restricting bead 205 is slightly larger than inner diameter 209 of the hollow tube 201, so the flow restricting bead 205 causes the filter material adjacent the bead 205 to be slightly compressed, and the flow restricting bead 205 is retained in the hollow tube 201 by friction. Dimension 213 of the flow restricting bead 205 is slightly smaller than inner diameter 209 of the hollow tube 201, to assist with insertion of the flow restricting bead 205 into the hollow tube 201. That is, the curved leading surface of the flow restricting bead 205 assists in inserting the flow restricting bead 205 into the tube 201. As shown schematically by the arrows, air and smoke drawn through the filter 103 during use of the smoking article is forced to flow around the flow restricting bead 205 and through a reduced cross section of filter material 203 of the hollow tube 201. In FIG. 2, the outer diameter 207 of the hollow tube 201 is 7.7 mm, the inner diameter 209 of the hollow tube 201 is 5.3 mm, the diameter of the flow restricting bead 205 is 6.0 mm, the length of the filter 103 is 21 mm and the centre of the flow restricting bead 205 is 11 mm from the downstream end of the filter 103. When the filter is circumscribed by tipping material, the diameter of the filter may be 7.73 mm.

(13) FIG. 3 is a cross sectional view of apparatus for manufacturing filters like that shown in FIG. 2, according to an embodiment of the invention. The apparatus 300 comprises an operating drum 301, a conveyor drum 303 and a collecting drum 305. FIG. 4 is a schematic perspective view of operating drum 301.

(14) Referring to FIGS. 3 and 4, each drum 301, 303, 305 includes a plurality of supports in the form of troughs 307 around its circumference. Each trough 307 is suitable for supporting a hollow tube 309 of filter material. The operating drum 301 further comprises inserting means 311 provided in each trough 307. Each inserting means 311 comprises two pistons 313 and will be described further with reference to FIGS. 5 and 6. The apparatus further comprises delivery means 315 for providing flow restricting beads 205 (like that shown in FIG. 2), and a manifold 317.

(15) Operation of apparatus 300 is as follows. Hollow tubes 309 of filter material are introduced via conveyor drum 303. Each hollow tube 309 is supported in a respective trough 307 on conveyor drum 303. Preferably, a vacuum is applied to conveyor drum 303 to secure the hollow tubes 309 in troughs 307. In the embodiment shown in FIGS. 3 and 4, conveyor drum 303 rotates in a clockwise direction.

(16) The hollow tubes 309 are then transferred from conveyor drum 303 onto operating drum 301, which rotates in the opposite direction to conveyor drum 303. In this embodiment, operating drum 301 rotates in an anti-clockwise direction. Each hollow tube 309 is supported in a respective trough 307 on operating drum 301. Again, preferably, a vacuum is applied to operating drum 301 to secure the hollow tubes 309 in troughs 307. Inserting means 311 are also provided in each trough 307 on operating drum 301. The inserting means 311 comprises two pistons 313 and, when the hollow tubes 309 are transferred from conveyor drum 303, each hollow tube 309 is positioned in the centre of the trough, with a piston 313 on either side of hollow tube 309. At delivery means 315, flow restricting beads 205 are provided. Each trough 307 receives two flow restricting beads 205. One flow restricting bead 205 is dispensed between the first piston 313 and the hollow tube 309 and another flow restricting bead 205 is dispensed between the second piston 313 and the hollow tube 309. As operating drum 301 rotates, the pistons 313 each move towards the hollow tube 309 to insert the flow restricting beads 205 into the hollow tubes 309. One flow restricting bead is received in each end of each hollow tube 309. The manifold 317 (not shown in FIG. 4 for clarity) is provided to prevent movement, damage or deformation of the hollow tubes relative to the operating drum as the flow restricting beads are being inserted.

(17) The process of inserting the flow restricting beads 205 into the hollow tubes will be described further with reference to FIGS. 5 and 6. Two positions V and VI are indicated in FIG. 4. Position V denotes a position at which the flow restricting beads 205 are dispensed from delivery means 315 and will be described further with reference to FIG. 5. Position VI denotes a position at which the flow restricting beads 205 have been inserted into the hollow tubes, and the pistons 313 are fully extended into the hollow tubes 309, and will be described further with reference to FIG. 6.

(18) The hollow tubes 309, each with two flow restricting beads 205 disposed therein, are then transferred from operating drum 301 onto collecting drum 305, which rotates in the opposite direction to operating drum 301. In this embodiment, collecting drum 305 rotates in a clockwise direction. Each hollow tube 309, with flow restricting beads 205 disposed therein, is supported in a respective trough 307 on collecting drum 305. Again, preferably, a vacuum is applied to collecting drum 305 to secure the hollow tubes 309 in troughs 307.

(19) FIGS. 5 and 6 show operation of the inserting means 311 provided in each trough 307 on operating drum 301. As already discussed, in this embodiment, each inserting means comprises two pistons 313 (denoted 313a and 313b in FIGS. 5 and 6). Each piston comprises a piston head (denoted 501a and 501b in FIGS. 5 and 6). The hollow tube 309 of filter material is positioned in the trough 307 such that piston 313a is on a first side of the hollow tube 309 and piston 313b is on a second side of the hollow tube 309. FIG. 5 shows the position of pistons 313a, 311b before the flow restricting beads 205 are inserted into the hollow tubes 309, for example at position V in FIG. 4. FIG. 6 shows the position of pistons 313a, 313b after the flow restricting means have been inserted into the hollow tubes 309, for example at position VI in FIG. 4.

(20) FIG. 5 also shows delivery means 315 for supplying flow restricting beads 205. In the embodiment shown in FIG. 5, two delivery means are provided, denoted 315a and 315b. Delivery means 315a is aligned to dispense a flow restricting bead 205 between piston 313a and the first end of the hollow tube 309. Delivery means 315b is aligned to dispense a flow restricting bead 205 between piston 313b and the first end of the hollow tube 309. Delivery means 315a comprises delivery ramp 503a and dispensing hopper 505a. Delivery means 315b comprises delivery ramp 503b and dispensing hopper 505b. Alternatively, a single hopper may be provided for both delivery means. Inserting means 311 also comprises positioning means in the form of sleeves 507a, 507b. Sleeve 507a is positioned between piston 313a and the first end of the hollow tube 309. The sleeve 507a has an aperture to receive a flow restricting bead 205 from dispensing hopper 505a. The inner diameter of sleeve 507a is preferably slightly larger than the piston 313a and the diameter 211 of flow restricting bead 205. Similarly, sleeve 507b is positioned between piston 313b and the second end of the hollow tube 309. The sleeve 507b has an aperture to receive a flow restricting bead 205 from dispensing hopper 505b. The inner diameter of sleeve 507b is preferably slightly larger than the piston 313b and the diameter 211 of flow restricting bead 205. Preferably, sleeves 507a, 507b are provided in each trough 307 on operating drum 301, although this is not shown in FIG. 4 for clarity.

(21) As the operating drum 301 rotates between position V and position VI, the pistons 313a, 313b move in the direction of the arrows shown in FIG. 5. Piston 313a is received in sleeve 507a and forces the flow restricting bead 205 into the bore of the hollow tube 309 at the first end. The piston heads 501a, 501b each have a diameter slightly smaller than the inner diameter 209 of hollow tube 309, such that they can be received in the bore of the hollow tube, with a small margin of clearance. The piston head 501a is received in the bore of the hollow tube 309 and the length of the piston head 501a is selected depending on the desired position of the flow restricting bead 205 in the first end of the hollow tube 309. Similarly, piston 313b is received in sleeve 507b and forces the flow restricting bead 205 into the bore of the hollow tube 309 at the second end. The piston head 501b is received in the bore of the hollow tube 309 and the length of the piston head 501b is selected depending on the desired position of the flow restricting bead 205 in the second end of the hollow tube 309. Once the pistons 313a, 313b are fully extended (FIG. 6), the flow restricting beads 205 are disposed in the desired positions within the hollow tube 309. The pistons may then be withdrawn as shown by the arrows in FIG. 6.

(22) In the embodiment illustrated in FIGS. 3, 4, 5 and 6, each hollow tube 309 of filter material has a length double that needed for a smoking article. Therefore, after the flow restricting beads 205 have been inserted into the hollow tubes 309, the hollow tubes 309 may be cut in two, thereby providing individual filters for smoking articles. The hollow tubes 309 may be cut in two prior to being combined with other elements into a smoking article. Alternatively, the double length hollow tubes 309 may be attached two tobacco rods, one at the first end and one at the second end, with tipping paper and subsequently cut to provide two finished smoking articles.

(23) Because the diameter 211 of the flow restricting beads 205 is larger than the inner diameter 209 of the hollow tubes 309, inserting a flow restricting bead 205 into a hollow tube 309 of filter material must overcome resistance due to friction. In the embodiment illustrated in FIGS. 3, 4, 5 and 6, this resistance is overcome in two ways. Firstly, the two flow restricting beads 205 are inserted into opposite ends of a hollow tube 309 simultaneously. The two forces exerted by pistons 313a and 313b are in opposite directions and counteract one another to assist in overcoming resistance. Thus, although the sleeves 507a, 507b are provided adjacent the hollow tube 309 to receive the pistons 313a, 313b and to correctly position the flow restricting beads 205 relative to the hollow tube 309, there is no need for an additional guiding sleeve within the hollow tube lumen. Secondly, the flow restricting beads 205 are spherical in shape and this means that the leading surface of a flow restricting bead 205, as it is inserted into the hollow tube 309, is curved. The flow restricting bead 205 has a leading cross sectional diameter 213 smaller than the inner diameter 209 of the hollow tube 309. This facilitates insertion of the flow restricting bead 205, even though the bead diameter 211 is larger than the inner diameter 209 of the hollow tube 309. In this embodiment, the material of the hollow tube 309 is sufficiently compressible and elastic to allow the bead to be inserted into the hollow tube bore. This may be achieved with several alternative shapes for the filter insert, for example, but not limited to, ovoid, ellipsoid, conical and teardrop-shaped. The manifold 317 (not shown in FIG. 4 for clarity) is provided to reduce the chance of movement or deformation of the hollow tubes as the flow restricting beads are being inserted.

(24) However, it is possible that the resistance due to friction may be overcome by only one of these two mechanisms. For example, the arrangement shown in FIGS. 3 and 4 may be used to insert filter inserts which are cylindrical in shape. The two forces exerted by pistons 313a and 313b will counteract one another and assist in overcoming the resistance faced when inserting the cylindrical filter inserts into the hollow tubes of filter material. For example, a spherical flow restricting bead 205 may be used but the flow restricting beads may be inserted individually, rather than in the double arrangement shown in FIGS. 3, 4 5 and 6. The curved leading surface of the flow restricting bead will assist in overcoming the resistance due to friction when inserting the flow restricting bead into a hollow tube of filter material. In that case, the flow restricting beads may be inserted either before or after the hollow tubes of filter material are combined with tobacco rods, or other aerosol forming substrates, to form smoking articles. Therefore, the method and apparatus of the invention may be simpler and more straightforward than methods and apparatus described in the prior art.