WO2012025437A1

WO2012025437A1 - Applicator for applying a coating of additive to a smoking article wrapping material, and associated method

Info

Publication number: WO2012025437A1
Application number: PCT/EP2011/064150
Authority: WO
Inventors: Karl Kaljura; Andrew Jonathan Bray; Gary Fallon; Peter Fossey
Original assignee: British American Tobacco (Investments) Limited
Priority date: 2010-08-23
Filing date: 2011-08-17
Publication date: 2012-03-01
Also published as: TW201225863A; GB201014050D0

Abstract

An applicator (1) for applying a coating of additive to a smoking article wrapping material (2) comprises a transport member (3) for transporting additive from an additive source (4); and a gaseous flow source (5) configured to provide a gaseous flow such that additive is blown from the transport member (3) onto the smoking article wrapping material (2), thereby to apply the coating.

Description

Applicator for applying a coating of additive to a smoking article wrapping material, and associated method.

Field of the Invention

This invention relates to applying a coating of additive to a smoking article wrapping material. In particular, but not exclusively, it relates to applying a coating of granular additive to a cigarette filter plugwrap.

Background of the Invention

Smoking articles such as cigarettes are often provided with filters for filtering smoke drawn from the cigarette. Such filters usually comprise a plug of cellulose acetate tow wrapped with a paper plugwrap.

It is known to provide a cigarette having a filter including an additive of granular activated carbon. When the cigarette is smoked, certain elements are removed from the smoke by the activated carbon.

It has been proposed to apply activated carbon granules to a filter plugwrap by lining a ribbon of plugwrap with glue and subsequently dropping the granules onto the glue-lined paper under gravity.

Summary of the Invention

The present invention provides an alternative approach to application of an additive to smoking article wrapping material.

The present invention provides an applicator for applying a coating of additive to a smoking article wrapping material, comprising a transport member for transporting additive from an additive source and a gaseous flow source configured to provide a gaseous flow such that additive is blown from the transport member onto the smoking article wrapping material, thereby to apply the coating. In this way, the transport member provides a feed of additive which is blown onto the wrapper by the gaseous flow to achieve desired coating properties in

dependence on the characteristics of the flow. Preferably, the gaseous flow source comprises an air-knife mechanism. The air- knife mechanism is configured to generate an air flow called an "air knife", which is a sheet of laminar airflow, preferably at high intensity and with low divergence. It has been found that the flow characteristics of the air knife result in a very even coating of additive.

The eventual coating may include uncoated regions. The wrapper may be coated with a predetermined pattern, which preferably comprises a plurality of spaced evenly coated regions along the length thereof. The additive is preferably in granular form. Preferably, the additive comprises activated carbon granules. However, instead of activated carbon, the additive may alternatively or in addition comprise another carbonaceous material and/or another additive for example a catalytic material. Preferably, however the additive comprises carbon. However, the additive may alternatively (or in addition) comprise, for example, a flavour additive, tobacco dust particles or reconstituted tobacco, or crystals such as menthol crystals.

It is not necessary for the coating to have any particular density, but a high density is preferred. In the case of low density coating there may be spaces between individual granules in the coating.

The coated regions are preferably evenly coated with a predetermined thickness, preferably less than 0.5 mm. However, the coating regions may include regions of increased/decreased thickness.

Optionally, the coating may have a thickness of the order of the thickness of the wrapping material. However, alternatively the coating may be substantially thinner or thicker than the wrapping material. The wrapping material preferably comprises a cigarette filter plugwrap. Optionally, however the wrapping material may be a cigarette paper suitable for wrapping a tobacco rod to form a cigarette.

Preferably, the transport member is a rotary transport member, which may comprise a sieve member for receiving the granular additive, the sieve member having openings sized to permit the passage of gas through the sieve member but to prevent the passage of the granular additive. The gaseous flow source is preferably configured to direct gaseous flow out of the sieve member, thereby to blow granule additive from the rotary transport member onto the wrapper.

The applicator may have a vacuum region arranged to provide suction through the sieve member so as to hold additive to the transport member as additive is transported from the additive source. The applicator may have a vacuum source configured to provide a pressure less than atmospheric pressure in the vacuum region.

Preferably, the vacuum region has a substantially hemi-annular cross section.

The applicator may include a further gaseous flow source configured to blow gas at the rotary member as it rotates from the eject position to the load position, thereby to clean the rotary transport member. Preferably, the gaseous flow source is configured to direct the gaseous flow downwards, and further preferably, substantially vertically downwards.

The applicator may include a trimming mechanism configured to trim excess additive from the transport member before the additive is blown onto the wrapper.

Preferably, the additive adheres to the wrapping material. Preferably, the gaseous flow source is an air flow source and the gaseous flow is an air flow.

The invention also provides a filter rod maker comprising the applicator. The invention also provides a method of applying a coating of additive to a smoking article wrapping material, comprising transporting additive from an additive source with a transport member and providing a gaseous flow to blow additive from the transport member onto the wrapper, thereby to coat the wrapping material with additive.

Brief description of the drawings

So that the invention may be more fully understood, an embodiment thereof will now be described by way of example with reference to the accompanying figures, in which:

Figure 1 is a perspective view of an applicator from a front viewpoint.

Figure 2 is a perspective view of the applicator from a rear viewpoint.

Figure 3 and 4 are cutaway views showing an interior region of the applicator.

Figure 5 is an exploded perspective view of the applicator.

Figure 6 is an exploded perspective view of the suction wheel of the applicator.

Detailed description

Figures 1 to 5 show an applicator 1 for applying a coating of activated carbon granules to a glue-lined ribbon of cigarette filter plugwrap paper 2. The ribbon of plugwrap 2 is conveyed by a conveyor (not shown) beneath a rotary transport member 3, which transports granules from a hopper 4 into the path of airflow generated by a stationary air knife mechanism 5. The airflow propels the granules from the rotary member 3 onto the plugwrap 2, where they adhere to the glue and thus coat the plugwrap 2 with a pattern 6.

The coated ribbon of plugwrap is received by a cigarette filter rod manufacturing machine (not shown), which makes filter rod by wrapping the plugwrap around an elongate rod of filter tow material, which is subsequently cut to form filter rod segments. Cigarette filter rod manufacturing machines are well known per se to those skilled in the art and will not be described in any further detail here.

As shown in Figures 1 to 5, hopper 4 is mounted over a sector of the rotary member 3 and is open at its bottom end so that the granules can pass by way of a gravity feed into the rotary member 3. As shown, hopper 4 has vertically extending sidewalls 7 to keep the granules in the hopper. Granules may be conveyed to the hopper by hand, or in a stream of air using a venturi mechanism or by other supply means.

As shown, rotary member 3 is rotated by a central axle 3a, which is driven by a motor (not shown) so as to rotate the rotary member 3 about an axis perpendicular to the direction of conveyance of the ribbon of paper 2. Referring to Figure 6, which shows an exploded view, the rotary member 3 has an annular shape and includes three concentric rings 9, 10, 11 : an inner ring 9, an outer ring 10 and a sieve ring 11 disposed between the outer ring 10 and the inner ring 9. As shown in Figure 5, which shows an exploded view of the applicator 1, the axle 3a is fixed at one end to circular vacuum sealing plate 3b, which rotates with the rotary member 3.

Referring again to Figure 6, outer ring 10 has a frame 12 comprising two concentric frame rings 12a connected by a plurality of frame ribs 12b which extend parallel to the axis of rotation of rotary member 3. The frame ribs 12b and rings 12a define a plurality of additive collection regions 13 spaced circumferentially around the rotary member 3. As shown in Figure 2, each collection region 13 has shallow radially extending walls 13a formed by the corresponding parts of the frame 12. As shown, the region bounded by the walls 13a is open to the sieve ring 11 so that a part of the sieve member 11 defines a floor 13b of each collection region onto which additive may be received.

The walls 13a of the collection regions 13 are arranged to contain the same predetermined quantity of additive within each collection region, and thus a regular distribution of additive on the paper can be obtained. As shown in Figure 3, the applicator 1 has a trimming brush 14 arranged to trim excess granules received from the hopper 4 by the rotary member 3. Trimming brush 14 is arranged to level the granules in the collection regions 13 so that each collection region 13 contains the same amount of activated carbon. The trimming brush 14 also removes any granules collected on the outer surface of the frame 11, 12. In this way, the trimming brush 14 ensures that granules are coated on the paper evenly to form a well defined regular pattern 6.

As shown in Figures 1 to 3, the pattern 6 is a repeated arrangement of spaced uniformly coated regions 6a. Each region 6a is spaced by a transverse uncoated gap 6b. The pattern 6 is defined by the structure of the frame 12. The particular pattern shown in Figures 1 to 3 is not intended to be limiting and the granules could be coated on the wrapper in any desired pattern by making appropriate

modifications to the frame 12.

The sieve ring 11 has pores sized to permit the passage of gas but to prevent the passage of the granules. In this way, granules can be supported on the floor 13b of each collection region and held/ejected by suction/airflow applied through the sieve member, as will now be described in more detail.

As shown in Figures 3 to 5, rotary member 3 is configured to rotate with respect to a central stationary hub member 15, which has a central bore 15a in which the axle 3a rotates. Hub member 15 is shaped to define a substantially hemi-annular vacuum region 16 for containing a low pressure to provide suction through the sieve member to hold granules in the collection regions 13. As shown in Figure 3, the vacuum region 16 is circumscribed by the sieve ring 11 so that at least part of the sieve ring defines the outer edge of the vacuum region 16 in each rotational position of the rotary member 3. Referring to Figure 5, the vacuum region 16 is sealed at one face by an inner wall of hub member 15 and by sealing plate 3b. The opposing face of vacuum chamber 16 is defined by the solid circular face 17a of a stationary vacuum transfer unit 17. Vacuum transfer unit 17 is provided with cylindrical vacuum channels 17b which open at the face 17a and which connect the vacuum region 16 with a vacuum pump (not shown) . The vacuum pump is configured to pump air from the vacuum region via the channels 17b, resulting in reduced pressure in the vacuum region so that suction is applied to the additive via the sieve member. Vacuum pumps are well known per se and will not be described here. As shown in Figure 4, the inner ring 9 has a plurality of holes 18 in register with the openings defined by the frame 12 of the outer ring 10 and thus with the floor 13b of each collection region 13. The inner ring 9 supports the sieve ring Hand the outer ring 10. It will be appreciated that many different sizes and shapes of the slots in the rings 9, 10 are possible so as to allow vacuum to reach the sieve ring 11 and retain the granules. Smaller openings lead to a larger suction force, and the openings in the rings 9, 10 may be sized so that a desired vacuum suction is provided to the granules to hold them in place until ejection.

Referring again to Figure 3, the stationary air knife mechanism 5 is mounted to the hub member 15 and is configured to direct air flow vertically downwards and out of the sieve member 11. The air knife mechanism 5 is configured to provide a constant supply of air, and rotary member 3 is configured to bring granules from the hopper 4 into the path of the air flow so that it is blown onto the plugwrap 2. Air knife mechanisms (also known as air blades) are known per se and thus will not be described in detail here. Briefly, the air knife mechanism 5 is configured to generate an air flow called an "air knife", which comprises a laminar sheet of compressed air with high pressure and low divergence. It has been found that the sheet of compressed air from the air knife results in a surprisingly even distribution of granules on the paper. Consequently, the eventual cigarette filters have a highly uniform activated carbon loading from filter to filter.

During operation of the applicator 1, the rotary member 3 rotates unidirectionally and granules fall under gravity from the hopper 4 into the collection regions 13. Granules received in the collection regions 13 in a load position of the rotary member are transported by the rotary member along a semicircular path and into an ej ection region below the air knife mechanism 5, where the granules are ejected onto the paper 2 by the air knife. The vacuum region 16 is shaped so that suction is applied through the air permeable floor 13b of each collection region 13 to hold granules in the rotary member 3 as it delivers granules to the ejection region. As shown in Figure 1, a surface 5a of the air knife mechanism forms a peripheral wall of the vacuum region and as a result the vacuum region does not overlap with the ej ection region. Thus, no suction is applied through the sieve member in the ej ection region. In other words, the vacuum region 16 is shaped so that the vacuum suction force is released just as the granules enter the path of the air knife.

Preferably, the activated carbon granules used in the applicator 1 have a mesh size of between 30 and 70 US mesh. However, the granules may have a mesh size of between 12 and 80 US mesh. The granules may, for example range in size from about 0.18mm to about 1.68mm and preferably range in size from 0.21mm to 0.60mm. Although the applicator 1 has been described above with reference to a wrapper in the form of a plugwrap paper, a different wrapper such as a cigarette paper or tipping paper could alternatively be coated by the applicator 1.

The applicator 1 may include a compressed air mechanism (not shown) positioned outside of the rotary member 3 and configured to clean the sieve ring as it rotates from the ej ection position back to the load position.

Many other modifications and variations will be evident to those skilled in the art, that fall within the scope of the following claims:

Claims

1. Applicator for applying a coating of additive to a smoking article wrapping material, comprising:

a transport member for transporting additive from an additive source;

a gaseous flow source configured to provide a gaseous flow such that additive is blown from the transport member onto the smoking article wrapping material, thereby to apply the coating.

2. Applicator as claimed in claim 1, wherein the gaseous flow source comprises an air knife mechanism and wherein the gaseous flow is an air knife.

3. Applicator as claimed in claim 1 or claim 2, wherein the gaseous flow source is configured to direct gaseous flow out of the transport member, thereby to blow additive from the transport member onto the wrapper.

4. Applicator as claimed in claim 3, wherein the transport member includes a sieve member, the sieve member having openings sized to permit the passage of gas through the sieve member but to prevent the passage of the additive, wherein the gaseous flow source is configured to direct gaseous flow out of the sieve member, thereby to blow additive from the transport member onto the wrapper.

5. Applicator as claimed in any of claim 4, wherein the transport member has one or more holes aligned with one or more corresponding regions of the sieve member, wherein each hole is sized to provide a predetermined suction force through each corresponding region of the sieve member.

6. Applicator as claimed in claim 4 or claim 5, further comprising a vacuum region arranged to provide suction through the sieve member so as to hold additive to the transport member as additive is transported from the additive source.

7 Applicator as claimed in claim 6, wherein the transport member is a rotary transport member configured to rotate relative to the vacuum region.

8. Applicator as claimed in claim 7, further comprising a hub member adapted to define the vacuum region, wherein the rotary transport member is configured to rotate relative to the hub member.

9. Applicator as claimed in claim 8, wherein the gaseous flow source is fixed in position with respect to the hub member.

10. Applicator as claimed in any of claims 7 to 9, wherein the sieve member is a sieve ring which circumscribes the vacuum region.

11. Applicator as claimed in any of claims 7 to 10, wherein the rotary transport member has a plurality of rotational positions in which at least part of the sieve member defines a peripheral region of the vacuum region.

12. Applicator as claimed in any of claims 6 to 11, wherein:

the transport member is configured to transport additive to an ej ection region;

the vacuum region is arranged so that no suction is applied through the sieve member in the ejection region, and

wherein the gaseous flow source is configured to direct the gaseous flow into the ejection region, thereby to blow additive from the transport member onto the wrapper.

13. Applicator as claimed in any preceding claim, wherein the transport member is a rotary transport member.

14. Applicator as claimed in claim 13, wherein the rotary transport member is configured to rotate relative to the gaseous flow source.

15. Applicator as claimed in claim 14, wherein the rotary transport member comprises a rotary ring which circumscribes the gaseous flow source.

16. Applicator as claimed in any of claims 13 to 15, wherein the rotary transport member is configured to rotate unidirectionally and wherein in each cycle of rotation the rotary transport member rotates from:

a load position in which additive is received from the additive source to an eject position in which additive received in the load position is blown from the rotary transport member onto the wrapper; and

from the eject position to the load position.

17. Applicator as claimed in any preceding claim, wherein the transport member has additive collection regions for collecting predetermined quantities of additive from the additive source, wherein the additive collection regions are arranged so that the wrapping material is coated with a predetermined pattern.

18. Applicator as claimed in claim 17, wherein the predetermined pattern comprises a plurality of spaced uniformly coated regions.

19. Applicator as claimed in any preceding claim, wherein the gaseous flow source is configured to direct the gaseous flow downwards.

20. Applicator as claimed in any preceding claim, further comprising the additive source, wherein the additive source is located so that additive can fall under gravity from the additive source into the transport member.

21. Applicator as claimed in any preceding claim, wherein the additive comprises a granular additive.

22. Applicator as claimed in any preceding claim, further comprising a conveyor configured to convey the wrapping material along a path beneath the transport member.

23. Applicator as claimed in any preceding claim, wherein the wrapping material is a filter plugwrap.

24. Filter rod maker for making filter rods for use in the manufacture of smoking articles comprising an applicator as claimed in claim 23.

25. Method of applying a coating of additive to a smoking article wrapping material, comprising:

transporting additive from an additive source with a transport member; providing a gaseous flow to blow additive from the transport member onto the wrapper, thereby to coat the wrapping material with additive.

26. Method as claimed in claim 25, wherein the gaseous flow is an air knife.

27. Method as claimed in claim 25 or claim 26, further comprising directing the gaseous flow out of the transport member, thereby to blow additive from the transport member onto the wrapper.

28. Applicator as substantially herein described with reference to the accompanying drawings.