CANVAS TRANSPORT GUIDE

Abstract

There is disclosed a method of applying additive to a web of crimped material for use in an aerosol-generating article, wherein: the web of crimped material has a width and a length; the web of crimped material travels along a pathway substantially parallel to the length of the web of crimped material at any given point along the pathway; the web of crimped material is deformed, over at least a portion of the pathway, across the width of the web of crimped material from a substantially flat configuration to a curved configuration; and additive is applied to a concave surface of the web of crimped material in the curved configuration.

Description

[0001] WEB CONVEYING GUIDE

[0002] The present disclosure relates to a device and method for shaping a web of material, for example a web of crimped material unwound from a bobbin. The shaped web of material may subsequently be gathered into a rod-shaped form for inclusion in an aerosol-generating article.

[0003] It is known to provide aerosol-generating articles in the form of rod-shaped consumables comprising a plurality of parts and components. The main components are normally a tobacco plug, or aerosol-generating substrate, one or more filter segments and optionally one or more cooling elements wrapped in multiple layers of paper to furnish a rod-shaped consumable aerosolgenerating article. Such aerosol-generating articles are typically used in combination with an aerosol-generating device into which an aerosol-generating article is at least partially inserted. The aerosol-generating device is configured controllably to heat the aerosol-generating substrate of the aerosol-generating article, thereby to generate an aerosol for inhalation by a consumer.

[0004] To date the filter components found in such products are formed into a continuous filter rod under heat and pressure from cellulose acetate tow combined with a triacetin plasticizer. Cellulose acetate filters are plastics and not readily biodegradable, thus posing challenges towards sustainability targets, in particular the introduction of a ban on single use plastics.

[0005] The production process of cellulose acetate tow involves a series of four key steps:

[0006] Step 1 : Spinning Solution Preparation

[0007] To initiate the process, cellulose acetate flakes and acetone are meticulously mixed together. A precise amount of titanium dioxide is introduced as a delustering agent for the final product. The mixture undergoes thorough blending, followed by an intensive filtration step to eliminate any particles that could obstruct the spinnerets.

[0008] Step 2: Spinning

[0009] The spinning phase commences when the spinning solution passes through a spinneret of a spinning cell. As the spinning solution emerges, the acetone begins to evaporate gradually. Consequently, the individual filaments solidify and intertwine, while the majority of the acetone is removed and recovered.

[0010] Step 3: Crimping

[0011] The solidified filaments from multiple spinnerets are combined, forming a cable comprising tens of thousands of filaments. This cable undergoes crimping in a stuffer box, imparting the distinctive structure characteristic of cigarette filter tow.

[0012] Step 4: Drying and Processing

[0013] Following crimping, the newly formed structure is subjected to drying to stabilize its shape and properties. Subsequently, the cigarette filter tow is compressed using bale presses, resulting in the formation of filter tow bales, ready for further processing and utilization.

[0014] Figure 1 shows a schematic overview of cellulose acetate cigarette filter production. A cellulose acetate filter forming apparatus 400 produces a continuous filter rod 401 , which is subsequently cut to length and combined with the other components of the rod-shaped consumables.

[0015] Cellulose acetate tow 409 is drawn from a bale of tow 412 and fed towards a first expansion roller 407 via a banding jet 410. The first expansion roller 407 and a second expansion roller 408 operate to widen the tow 409 into a flat sheet. The widened, flat sheet of tow 409 then travels through a plasticizer chamber 405 and plasticizer is applied to the tow 409 via a plasticizer applicator 406. A cross-sectional view ‘b’ of tow 409 is shown in Figure 4. The tow 409 subsequently travels through a forming funnel 404, illustrated in Figure 2, before the formed tow 411 passes to a garniture area for subsequent wrapping by wrapping material 414, such as plug wrap, in a paper wrapping area 403. In the garniture area, an endless garniture belt 416 passes over driven garniture rollers 415. The garniture belt 416 passes along a progressively deepening groove in a garniture bed 417 at the top of the garniture area. The wrapping material 414, in the form of a band, is unwound from a bobbin 413 and travels along the garniture bed 417 on top of the garniture belt 416, with the formed tow 411 on top the band of wrapping material 414. The garniture belt 416 and the band of wrapping material 414 are caused to wrap longitudinally around the formed tow 411 as the garniture belt 416 travels along the progressively deepening groove. A cross-sectional view ‘a’ is shown in Figure 3. Adhesives used to join each end of the plug wrap are cured in a heating block 402 to furnish a continuous filter rod 401.

[0016] It is also known to form cooling elements found in rod-shaped consumables from a plastic material, for example crimped polylactic acid (PLA) film. Cooling elements comprising such a material are not readily biodegradable, thus also posing challenges towards sustainability targets.

[0017] Figure 5 shows a schematic representation of an apparatus and manufacturing method for a continuous rod of crimped material web 200. The apparatus and method for forming a continuous rod of crimped material web 200 can be used to form rods from web materials such as PLA, tobacco and paper-based materials supplied from a continuous web material bobbin 141. A continuously crimped tobacco rod can be formed from a tobacco sheet (cast leaf sheet or reconstituted tobacco sheet) or a paper-based filter element, constructed from paper-based materials or other non-woven materials. It should therefore be understood that the referenced material web 140 can be selected from the various materials mentioned above.

[0018] A material web 140 is supplied from a material web bobbin 141 towards a first crimping roller 502 and a second crimping roller 503, also shown in Figure 6. The crimping rollers are designed so that the teeth from one of the rollers meshes with the grooves on the other roller. Passing the material web 140 between the crimping rollers 502, 503 furnishes a crimped material web 145, as shown in Figure 7.

[0019] With reference now to Figures 8 and 9, these show the material web before and after crimping via crimping rollers 502, 503. Figure 8 shows the material web entering a gap between the respective crimping rollers as a continuous web of material 140. Figure 9 shows the crimped web of material 145 leaving the crimping rollers 502, 503.

[0020] Referring back to Figure 5, the web of crimped material 145 is then optionally supplied with an additive, such as a flavouring, from additive applicator 121 in an after-cut chamber 120. Due to the additive being sprayed onto a substantially planar web of crimped material, there may be a high degree of variability in the distribution of additive across the width of the material web. Furthermore, to distribute the additive more evenly towards the edges of the material web, overspray may occur, leading to the waste of additive. The crimped material web is then formed into a continuous substantially cylindrical cylinder, via a star and ring tool 510, as shown in more detail in Figures 10 and 11. Before passing through a forming funnel 404 towards garniture belt 416, the crimped and formed material web 150 may be wrapped in plug wrap in the same manner as previously described for formation of a continuous rod of cellulose acetate filter to furnish a continuous rod of crimped material web 200 that can subsequently be cut to length and combined with other components of a rod-shaped consumable. A cross sectional view ‘c’ is marked on Figure 5 and view ‘c’ is provided in Figure 12.

[0021] With reference now to Figures 10 and 11 , these show representations of the star and ring tool 510, which is used to form the crimped material web 145 into a semi-cylindrical shape. The star and ring tool is formed from a ring 511 adjoined to a star 512 and positioned in line with the garniture belt, formation funnel and crimping rollers. The star and ring tool 510 is designed such that the crimped material web envelopes around the upper portions of the star 512 and ring 511 , such that the material web forms a semi-cylinder around the star and ring tool 510, with the material web being continuously pulled in the direction of travel marked on Figure 11 .

[0022] Considering the above background information and the current use of plastics-based components for elements of rod-shaped consumables, it would be desirable to replace these components with more sustainable materials, for instance paper-based materials.

[0023] Moreover, when using the apparatus of Figure 5 to form a continuous rod of crimped web material, a limitation exists in the efficiency of additive addition via applicator 121 , in that the additive distribution across the web of material has to be limited in order to prevent overspray of the additive. The additive may provide the continuous rod of crimped web material with additional sensorial, mechanical or filtration properties. The desired properties imparted by the application of additive are dependent on the material web used and the desired component to be produced. For example, when producing a crimped tobacco rod using a web of tobacco-based material, it may be desirable to enhance sensorial properties through the application of flavouring. When producing a continuous rod of crimped paper-based filter, it may be desirable that suitable additives are applied to furnish the desired mechanical and filtration characteristics of the finished paper-based filter component. As shown in Figures 12 to 14, a problem arises when spraying additive 205 from the applicator 121 onto a convex web of crimped material 145. Because of the convex profile of the web of crimped material 145, the additive 205 will tend to be applied in a greater concentration at the central part of the top of the convex profile of the web of crimped material 145, and at a lesser concentration towards the edges of the web of crimped material 145. There may also be overspray, where additive 205 does not contact the web of crimped material at all, but is wasted. The over-spray may also result in additive 205 being applied to machinery parts where the presence of additive 205 is not wanted.

[0024] Figure 15 illustrates a further problem with the known method for spraying additive 205. Because the additive 205 is applied to the convex surface of the web of crimped material 145, there will tend to be a greater concentration of additive 205 on outer surfaces of the gathered and formed web of crimped material 150 after passage through the forming funnel 404 and the garniture area. The resulting rod-shaped consumable 200, shown in cross-section in Figure 15, will comprise a rod-shaped core of gathered and formed crimped material 150 within a circumferential wrapper 414, with an outer annulus 151 with a high concentration of additive 205 and an inner core 152 with a low concentration of additive 205. The high concentration of additive 205 in the outer annulus 151 may migrate through the circumferential wrapper 414, resulting in unwanted staining.

[0025] According to a first aspect of the present invention, there is provided a method of applying additive to a web of crimped material for use in an aerosol-generating article, wherein: the web of crimped material has a width and a length; the web of crimped material travels along a pathway substantially parallel to the length of the web of crimped material at any given point along the pathway; the web of crimped material is deformed, over at least a portion of the pathway, across the width of the web of crimped material from a substantially flat configuration to a curved configuration; and additive is applied to a concave surface of the web of crimped material in the curved configuration.

[0026] By deforming the web of crimped material to a curved configuration and applying additive to the concave surface of the web of crimped material, a number of advantages are obtained.

[0027] Firstly, the additive can be applied more evenly. For example, if additive is sprayed from an applicator located at or close to a centre of curvature of the concave surface, then a distance from the applicator to each part of the concave surface will be substantially the same, and a fanshaped spray of additive may result in more even distribution of the additive to the concave surface of the web of crimped material. This is in contrast to spraying additive onto a substantially flat planar web of crimped material, where there may tend to be a concentration of additive at a central part of the web of crimped material due to the central part being closer to the applicator than edge parts of the web of crimped material.

[0028] Secondly, by applying additive to the concave surface of the web of crimped material, additive is applied to a surface of the web of crimped material that will later form an inner part of a rod or cylinder after the web of crimped material has been gathered and wrapped in a wrapper. Accordingly, there is less likelihood of excess additive contacting an inner surface of the wrapper and potentially migrating through the wrapper.

[0029] Thirdly, by applying additive to a concave surface rather than to a substantially flat planar surface or a convex surface, there is less risk of overspray, where excess additive is sprayed beyond the edges of the web of crimped material, potentially leading to wastage of additive or unwanted application of additive to other machine parts.

[0030] The additive may be sprayed onto the concave surface. The additive may be painted onto the concave surface. The additive may be brushed onto the concave surface. The additive may be spread onto the concave surface. The additive may be poured onto the concave surface.

[0031] The additive may be a liquid. The additive may be a powder. The additive may be a slurry. The additive may be a gel. The additive may be a mist of liquid droplets.

[0032] The additive may consist of or may comprise a flavouring additive. For example, the additive may include one or more of: menthol, tobacco flavour extracts, other plant-based flavour extracts, synthetic flavourings.

[0033] The concave surface of the web of crimped material may face upwardly and the additive may be applied from above. This may help to contain the additive within the curvature of the concave surface of the web of crimped material.

[0034] Alternatively, the concave surface of the web of crimped material may face downwardly and the additive may be applied from below. This may help to reduce overapplication of additive to the web of crimped material, with excess additive falling away from the web of crimped material under gravity. A drip tray or similar receptacle may be provided underneath the additive applicator to catch excess additive falling from the web of crimped material.

[0035] The web of crimped material, after application of the additive, may be further deformed into a rod or cylinder, with the concave surface facing inwardly. The web of crimped material may be further deformed by way of a gathering operation. For example, the web of crimped material may be passed through a funnel so as to cause the web of crimped material to be gathered into a rod or cylinder.

[0036] The rod or cylinder may be circumferentially wrapped with a wrapper. The wrapping may take place by transporting the rod or cylinder along a garniture belt that progressively wraps a longitudinal wrapper circumferentially around the rod or cylinder.

[0037] As previously discussed, applying additive to the concave surface of the web of crimped material that subsequently forms an inner part of a wrapped rod or cylinder may reduce the likelihood of unwanted migration of additive through the wrapper. For example, a liquid additive might cause unwanted staining of an external surface of the wrapper if such migration occurs.

[0038] The wrapped rod or cylinder may be subsequently cut across its length into individual wrapped elements.

[0039] The web of crimped material may comprise reconstituted tobacco. The web of crimped material may comprise tobacco cast leaf. This is useful when the web of crimped material is being used to form an aerosol-generating substrate.

[0040] The web of crimped material may comprise paper. The web of crimped material may comprise cellulose acetate tow. The web of crimped material may comprise polylactic acid, PLA.

[0041] This is useful when the web of crimped material is being used to form a filter element or an aerosol-cooling element.

[0042] The web of crimped material may be fed through a guide device comprising a body portion with a forward end, a rearward end, a solid bottom surface, first and second solid side surfaces, and a partially open top surface, wherein the body portion comprises a partially cylindrical bore having a longitudinal axis extending from the rearward end to the forward end, the partially cylindrical bore having a curved longitudinal wall, and a front surface sloping downwardly from the top surface to the bottom surface in a direction towards the forward end, the front surface and the side surfaces flaring outwardly from the top surface towards the bottom surface so as to define a guide surface, and wherein the web of crimped material transitions from the substantially flat configuration at a bottom edge of the guide surface to the curved configuration conformed to the longitudinal wall of the partially cylindrical bore as the web of crimped material passes through the guide device from the forward end and through the partially cylindrical bore to the rearward end.

[0043] The guide device is useful for shaping the web of crimped material so as to take on the desired curved configuration.

[0044] The guide surface of the guide device is shaped and configured so as to cause the web of crimped material to transition smoothly from a substantially flat configuration (i.e. as unwound from a bobbin) into a curved configuration generally about the longitudinal axis in the partially cylindrical bore. The curved configuration of the web of crimped material may be a partially cylindrical curved configuration. The curved configuration of the web of crimped material may be a substantially semi-cylindrical curved configuration.

[0045] The web of crimped material is crimped, for example by being passed between a set of crimping rollers, prior to passage through the guide device.

[0046] Forming the web of crimped material into a curved configuration as the web of crimped material passes through the guide device means that an additive can be applied to the concave surface of the web of crimped material while in the curved configuration. This may allow more even and more efficient application of additive. The guide surface may have a triangular shape that is wider at the bottom than at the top. Such a shape may help to guide the web of crimped material into the partially cylindrical bore.

[0047] A bottom edge of the guide surface may be provided with a tongue portion that curves downwardly, and the web of crimped material may pass over the tongue portion before passing over the guide surface. The tongue portion may facilitate a smooth transition of the web of crimped material onto the guide surface.

[0048] An upper surface of the tongue portion may be provided with a knurled or patterned surface to reduce friction between the web of crimped material and the tongue portion as the web of crimped material passes over the tongue portion.

[0049] The guide surface may be provided with a knurled or patterned surface to reduce friction between the web of crimped material and the guide surface as the web of crimped material passes over the guide surface.

[0050] The partially cylindrical bore may have a substantially constant diameter along the longitudinal axis.

[0051] Alternatively, the partially cylindrical bore may have a diameter that progressively decreases from the forward end to the rearward end along the longitudinal axis. In this way, a radius of curvature of the concave surface of the web of crimped material may decrease from the forward end to the rearward end along the longitudinal axis. This may facilitate subsequent wrapping of the web of crimped material.

[0052] The partially open top surface may slope downwardly from the rearward end towards the forward end along the longitudinal axis. The partially open top surface may slope downwardly from the rearward end towards the forward end at an angle smaller than an angle by which the front surface slopes downwardly from the top surface to the bottom surface.

[0053] The partially open top surface may have an elongate open slot extending from the rearward end to the forward end. The elongate open slot may have a width that progressively increases from the rearward end towards the forward end.

[0054] The additive may be applied onto the web of crimped material with an applicator. The applicator may comprise at least one spray nozzle disposed at an open part of the partially open top surface. The applicator may comprise at least one spray nozzle disposed at the forward end of the guide device where the guide surface transitions into the partially cylindrical bore.

[0055] The web of crimped material may pass over a roller disposed adjacent and substantially parallel to a bottom edge of the guide surface, and the roller may direct the web of crimped material onto the guide surface. This may help to reduce unwanted bunching of the web of crimped material.

[0056] According to a second aspect of the present invention, there is provided an apparatus for applying additive to a web of crimped material for use in an aerosol-generating article, the apparatus comprising: a plurality of guides for guiding the web of crimped material along a pathway, the web of material having a width and a length, and the pathway being substantially parallel to the length of the web of crimped material at any given point along the pathway; at least one deforming element configured to deform the web of crimped material, over at least a portion of the pathway, across the width of the web of crimped material from a substantially flat configuration to a curved configuration; and an applicator configured to apply additive to a concave surface of the web of crimped material in the curved configuration.

[0057] By deforming the web of crimped material to a curved configuration and applying additive to the concave surface of the web of crimped material, a number of advantages are obtained.

[0058] Firstly, the additive can be applied more evenly. For example, if additive is sprayed from an applicator located at or close to a centre of curvature of the concave surface, then a distance from the applicator to each part of the concave surface will be substantially the same, and a fanshaped spray of additive may result in more even distribution of the additive to the concave surface of the web of crimped material. This is in contrast to spraying additive onto a substantially flat planar web of crimped material, where there may tend to be a concentration of additive at a central part of the web of crimped material due to the central part being closer to the applicator than edge parts of the web of crimped material.

[0059] Secondly, by applying additive to the concave surface of the web of crimped material, additive is applied to a surface of the web of crimped material that will later form an inner part of a rod or cylinder after the web of crimped material has been gathered and wrapped in a wrapper. Accordingly, there is less likelihood of excess additive contacting an inner surface of the wrapper and potentially migrating through the wrapper.

[0060] Thirdly, by applying additive to a concave surface rather than to a substantially flat planar surface or a convex surface, there is less risk of overspray, where excess additive is sprayed beyond the edges of the web of crimped material, potentially leading to wastage of additive or unwanted application of additive to other machine parts.

[0061] The applicator may be a spray applicator. The applicator may be a liquid applicator. The applicator may be a powder applicator. The applicator may be a solids applicator.

[0062] The additive may be a liquid. The additive may be a powder. The additive may be a slurry. The additive may be a gel. The additive may be a mist of liquid droplets.

[0063] The additive may consist of or may comprise a flavouring additive. For example, the additive may include one or more of: menthol, tobacco flavour extracts, other plant-based flavour extracts, synthetic flavourings.

[0064] The at least one deforming element may be configured to deform the web of crimped material so that the concave surface of the web of crimped material faces upwardly, and the applicator may be configured to apply additive from above. This may help to contain the additive within the curvature of the concave surface of the web of crimped material.

[0065] Alternatively, the at least one deforming element may be configured to deform the web of crimped material so that the concave surface of the web of crimped material faces downwardly, and the applicator may be configured to apply additive from below. This may help to reduce overapplication of additive to the web of crimped material, with excess additive falling away from the web of crimped material under gravity. A drip tray or similar receptacle may be provided underneath the additive applicator to catch excess additive falling from the web of crimped material.

[0066] The apparatus may further comprising a gathering component configured to gather and further deform the web of crimped material, after application of the additive, into a rod or cylinder, with the concave surface facing inwardly. The gathering component may be a funnel.

[0067] The apparatus may further comprise a wrapping component configured to wrap the rod or cylinder circumferentially with a wrapper. The wrapping component may comprise a garniture belt.

[0068] The apparatus may further comprise a cutting component configured to cut the wrapped rod or cylinder across its length into individual wrapped elements. The cutting component may comprise a knife.

[0069] The web of crimped material may comprise reconstituted tobacco. The web of crimped material may comprise tobacco cast leaf. This is useful when the web of crimped material is being used to form an aerosol-generating substrate.

[0070] The web of crimped material may comprise paper. The web of crimped material may comprise cellulose acetate tow. The web of crimped material may comprise polylactic acid, PLA.

[0071] This is useful when the web of crimped material is being used to form a filter element or an aerosol-cooling element.

[0072] According to a third aspect of the present invention, there is provided a guide device for shaping a web of crimped material, the guide device comprising a body portion with a forward end, a rearward end, a solid bottom surface, first and second solid side surfaces, and a partially open top surface, wherein the body portion comprises a partially cylindrical bore having a longitudinal axis extending from the rearward end to the forward end, the partially cylindrical bore having a curved longitudinal wall, and a front surface sloping downwardly from the partially open top surface to the bottom surface in a direction towards the forward end, the front surface and the side surfaces flaring outwardly from the partially open top surface towards the bottom surface so as to define a guide surface configured to feed the web of crimped material smoothly into the partially cylindrical bore such that the web of crimped material transitions from a substantially flat configuration to a curved configuration conformed to the curved longitudinal wall of the partially cylindrical bore as the web of crimped material passes through the guide device from the forward end to the rearward end.

[0073] The guide device is useful for shaping the web of crimped material so as to take on the desired curved configuration.

[0074] The guide surface of the guide device is shaped and configured so as to cause the web of crimped material to transition smoothly from a substantially flat configuration (i.e. as unwound from a bobbin) into a curved configuration generally about the longitudinal axis in the partially cylindrical bore. The curved configuration of the web of crimped material may be a partially cylindrical curved configuration. The curved configuration of the web of crimped material may be a substantially semi-cylindrical curved configuration.

[0075] The web of crimped material is crimped, for example by being passed between a set of crimping rollers, prior to passage through the guide device.

[0076] Forming the web of crimped material into a curved configuration as the web of crimped material passes through the guide device means that an additive can be applied to the concave surface of the web of crimped material while in the curved configuration. This may allow more even and more efficient application of additive.

[0077] The guide surface may have a triangular shape that is wider at the bottom than at the top. Such a shape may help to guide the web of crimped material into the partially cylindrical bore.

[0078] A bottom edge of the guide surface may be provided with a tongue portion that curves downwardly. The web of crimped material may pass over the tongue portion before passing over the guide surface. The tongue portion may facilitate a smooth transition of the web of crimped material onto the guide surface.

[0079] An upper surface of the tongue portion may be provided with a knurled or patterned surface to reduce friction between the web of crimped material and the tongue portion.

[0080] The guide surface may be provided with a knurled or patterned surface to reduce friction between the web of crimped material and the guide surface.

[0081] The partially cylindrical bore may have a substantially constant diameter along the longitudinal axis.

[0082] Alternatively, the partially cylindrical bore may have a diameter that progressively decreases from the forward end to the rearward end along the longitudinal axis. In this way, a radius of curvature of the concave surface of the web of crimped material may decrease from the forward end to the rearward end along the longitudinal axis. This may facilitate subsequent wrapping of the web of crimped material.

[0083] The partially open top surface may slope downwardly from the rearward end towards the forward end along the longitudinal axis. The partially open top surface may slope downwardly from the rearward end towards the forward end at an angle smaller than an angle by which the front surface slopes downwardly from the top surface to the bottom surface. The partially open top surface may have an elongate open slot extending from the rearward end to the forward end. The elongate open slot may have a width that progressively increases from the rearward end towards the forward end.

[0084] The guide device may be made of metal. The guide device may be made of steel. The guide device may be made of stainless steel.

[0085] The guide device may be provided in combination with an applicator configured to apply an additive onto the web of crimped material.

[0086] The applicator may comprise at least one spray nozzle disposed at an open part of the partially open top surface. The applicator may comprise at least one spray nozzle disposed at the forward end of the guide device where the guide surface transitions into the partially cylindrical bore. The applicator may be configured to spray the additive onto the web of crimped material while the web of crimped material is in the curved configuration.

[0087] The guide device may be provided in combination with a roller disposed adjacent and substantially parallel to a bottom edge of the guide surface, and the roller may be configured to direct the web of crimped material onto the guide surface. This may help to reduce unwanted bunching of the web of crimped material.

[0088] According to a fourth aspect of the present invention, there is provided an apparatus of the second aspect, wherein the at least one deforming element comprises the guide device of the third aspect.

[0089] Embodiments of the present invention may provide several advantages over the prior art. Cost savings may be obtained by a reduction in additive overspray and additive wastage, since application onto a concave surface helps to contain the spray of additive and reduce run-off. Efficiency may be improved by reducing unwanted fouling of machine components with oversprayed additive. The resulting consumables will tend to have a greater concentration of additive nearer a core of the consumable rather than an outer surface of the consumable, thus reducing the risk of additive migration through a wrapper of the consumable.

[0090] In the context of the present disclosure, the term “additive” is intended to mean a substance that is applied to a crimped material web by way of an applicator. The additive may be one or more of a liquid, a powder, a slurry, a gel or a mist of liquid droplets. The additive may consist of or may comprise a flavouring additive. For example, the additive may include one or more of: menthol, tobacco flavour extracts, other plant-based flavour extracts, synthetic flavourings.

[0091] In the context of the present disclosure, the term “aerosol-generating article” is intended to mean an article comprising an aerosol-generating substrate that is configured to be used with an aerosol-generating device. The aerosol-generating substrate may comprise a nicotine-containing substance, e.g. tobacco. The article may comprise additional components such as a mouthpiece, an aerosol mixing portion, a filter portion, a flavour portion and so forth. An aerosol-generating article preferably has a rod-like or cylindrical form factor. An aerosol-generating article preferably has a constant cross-section along its length, which may be circular, elliptical or oval, but could also have other shapes, including polygonal.

[0092] In the context of the present disclosure, the term “aerosol-generating substrate” is intended to mean a substrate that is capable of generating an aerosol when heated. Examples of aerosolgenerating substrates include tobacco cast leaf formed from a slurry of ground tobacco leaves and suitable binders, and also mixtures of nicotine with one or more of glycerine, guar gum, menthol, cloves, other flavourings, other agricultural products, or high retention material with nicotine content.

[0093] In the context of the present disclosure, the term “crimping” is used to describe processing a sheet of material in order to form a crimped sheet of material comprising plural corrugations or ridges and grooves.

[0094] In the context of the present disclosure, the term “web of material” refers to a laminar element having a width and a length substantially greater than the thickness thereof. Preferably, the sheet of material has a width of 60 millimetres to 300 millimetres, preferably of 80 millimetres to 200 millimetres, most preferably of 100 millimetres to 150 millimetres. Preferably, the web of material has a thickness of 50 micrometres to 500 micrometres, optionally of 100 micrometres to 400 micrometres, optionally of 150 micrometres to 350 micrometres, optionally of 175 micrometres to 275 micrometres, optionally of 200 micrometres to 250 micrometres, optionally around 215 micrometres. The length of the web of material is not of particular importance in the context of the present disclosure. Generally, the web of material is unwound from a bobbin, and may have a length of tens or hundreds of metres.

[0095] In the context of the present disclosure, the term “web of crimped material” refers to a web of material, as defined above, after the web of material has been crimped, for example by passage between a pair of crimping rollers.

[0096] In the context of the present disclosure, the terms “upstream” and “downstream” are used to describe the relative positions of components of the apparatus or steps of the method with reference to a direction of travel of the web of crimped material.

[0097] The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0098] Example Ex1 : A method of applying additive to a web of crimped material for use in an aerosol-generating article, wherein: the web of crimped material has a width and a length; the web of crimped material travels along a pathway substantially parallel to the length of the web of crimped material at any given point along the pathway; the web of crimped material is deformed, over at least a portion of the pathway, across the width of the web of crimped material from a substantially flat configuration to a curved configuration; and additive is applied to a concave surface of the web of crimped material in the curved configuration.

[0099] Example Ex2: The method of Example Ex1 , wherein the additive is sprayed onto the concave surface.

[0100] Example Ex3: The method of Example Ex1 , wherein the additive is painted onto the concave surface.

[0101] Example Ex4: The method of Example Ex1 , wherein the additive is brushed onto the concave surface.

[0102] Example Ex5: The method of Example Ex1 , wherein the additive is spread onto the concave surface.

[0103] Example Ex6: The method of Example Ex1 , wherein the additive is poured onto the concave surface.

[0104] Example Ex7: The method of any one of Examples Ex1 to Ex6, wherein the concave surface of the web of crimped material faces upwardly and wherein the additive is applied from above.

[0105] Example Ex8: The method of any one of Examples Ex1 to Ex6, wherein the concave surface of the web of crimped material faces downwardly and wherein the additive is applied from below.

[0106] Example Ex9: The method of any one of Examples Ex1 to Ex8, wherein the web of crimped material, after application of the additive, is further deformed into a rod or cylinder, with the concave surface facing inwardly.

[0107] Example Ex10: The method of Example Ex9, wherein the rod or cylinder is circumferentially wrapped with a wrapper.

[0108] Example Ex11 : The method of Example Ex10, wherein the wrapped rod or cylinder is subsequently cut across its length into individual wrapped elements.

[0109] Example Ex12: The method of any preceding Example, wherein the web of crimped material comprises reconstituted tobacco.

[0110] Example Ex13: The method of any one of Examples Ex1 to Ex11 , wherein the web of crimped material comprises tobacco cast leaf.

[0111] Example Ex14: The method of any one of Examples Ex1 to Ex11 , wherein the web of crimped material comprises paper.

[0112] Example Ex15: The method of any one of Examples Ex1 to Ex11 , wherein the web of crimped material comprises cellulose acetate tow. Example Ex16: The method of any one of Examples Ex1 to Ex11 , wherein the web of crimped material comprises polylactic acid, PLA.

[0113] Example Ex17: The method of any preceding Example, wherein the web of crimped material is fed through a guide device comprising a body portion with a forward end, a rearward end, a solid bottom surface, first and second solid side surfaces, and a partially open top surface, wherein the body portion comprises a partially cylindrical bore having a longitudinal axis extending from the rearward end to the forward end, the partially cylindrical bore having a curved longitudinal wall, and a front surface sloping downwardly from the top surface to the bottom surface in a direction towards the forward end, the front surface and the side surfaces flaring outwardly from the top surface towards the bottom surface so as to define a guide surface, and wherein the web of crimped material transitions from the substantially flat configuration at a bottom edge of the guide surface to the curved configuration conformed to the longitudinal wall of the partially cylindrical bore as the web of crimped material passes through the guide device from the forward end and through the partially cylindrical bore to the rearward end.

[0114] Example Ex18: The method of Example Ex17, wherein the guide surface has a triangular shape that is wider at the bottom than at the top.

[0115] Example Ex19: The method of Example Ex17 or Ex18, wherein a bottom edge of the guide surface is provided with a tongue portion that curves downwardly, and wherein the web of crimped material passes over the tongue portion before passing over the guide surface.

[0116] Example Ex20: The method of Example Ex19, wherein an upper surface of the tongue portion is provided with a knurled or patterned surface to reduce friction between the web of crimped material and the tongue portion as the web of crimped material passes over the tongue portion.

[0117] Example Ex21 : The method of any one of Examples Ex17 to Ex20, wherein the guide surface is provided with a knurled or patterned surface to reduce friction between the web of crimped material and the guide surface as the web of crimped material passes over the guide surface.

[0118] Example Ex22: The method of any one of Examples Ex17 to Ex21 , wherein the partially cylindrical bore has a substantially constant diameter along the longitudinal axis.

[0119] Example Ex23: The method of any one of Examples Ex17 to Ex21 , wherein the partially cylindrical bore has a diameter that progressively decreases from the forward end to the rearward end along the longitudinal axis.

[0120] Example Ex24: The method of any one of Examples Ex17 to Ex23, wherein the partially open top surface slopes downwardly from the rearward end towards the forward end along the longitudinal axis.

[0121] Example Ex25: The method of any one of Examples Ex17 to Ex23, wherein the partially open top surface slopes downwardly from the rearward end towards the forward end at an angle smaller than an angle by which the front surface slopes downwardly from the top surface to the bottom surface.

[0122] Example Ex26: The method of any one of Examples Ex17 to Ex25, wherein the partially open top surface has an elongate open slot extending from the rearward end to the forward end.

[0123] Example Ex27: The method of Example Ex26 depending from Example Ex24 or Example Ex25, wherein the elongate open slot has a width that progressively increases from the rearward end towards the forward end.

[0124] Example Ex28: The method of any one of Examples Ex17 to Ex27, wherein the additive is applied onto the web of crimped material with an applicator.

[0125] Example Ex29: The method of Example Ex28, wherein the applicator comprises at least one spray nozzle disposed at an open part of the partially open top surface.

[0126] Example Ex30: The method of Example Ex28, wherein the applicator comprises at least one spray nozzle disposed at the forward end of the guide device where the guide surface transitions into the partially cylindrical bore.

[0127] Example Ex31 : The method of any one of Examples Ex17 to Ex30, wherein the web of crimped material passes over a roller disposed adjacent and substantially parallel to a bottom edge of the guide surface, and wherein the roller directs the web of crimped material onto the guide surface.

[0128] Example Ex32: An apparatus for applying additive to a web of crimped material for use in an aerosol-generating article, the apparatus comprising: a plurality of guides for guiding the web of crimped material along a pathway, the web of material having a width and a length, and the pathway being substantially parallel to the length of the web of crimped material at any given point along the pathway; at least one deforming element configured to deform the web of crimped material, over at least a portion of the pathway, across the width of the web of crimped material from a substantially flat configuration to a curved configuration; and an applicator configured to apply additive to a concave surface of the web of crimped material in the curved configuration.

[0129] Example Ex33: The apparatus of Example Ex32, wherein the applicator is a spray applicator.

[0130] Example Ex34: The apparatus of Example Ex32, wherein the applicator is a liquid applicator.

[0131] Example Ex35: The apparatus of Example Ex32, wherein the applicator is a powder applicator.

[0132] Example Ex36: The apparatus of Example Ex32, wherein the applicator is a solids applicator. Example Ex37: The apparatus of any one of Examples Ex32 to Ex36, wherein the at least one deforming element is configured to deform the web of crimped material so that the concave surface of the web of crimped material faces upwardly, and wherein the applicator is configured to apply additive from above.

[0133] Example Ex38: The apparatus of any one of Examples Ex32 to Ex36, wherein the at least one deforming element is configured to deform the web of crimped material so that the concave surface of the web of crimped material faces downwardly, and wherein the applicator is configured to apply additive from below.

[0134] Example Ex39: The apparatus of any one of Examples Ex32 to Ex38, further comprising a gathering component configured to gather and further deform the web of crimped material, after application of the additive, into a rod or cylinder, with the concave surface facing inwardly.

[0135] Example Ex40: The apparatus of Example Ex39, further comprising a wrapping component configured to wrap the rod or cylinder circumferentially with a wrapper.

[0136] Example Ex41 : The apparatus of Example Ex40, further comprising a cutting component configured to cut the wrapped rod or cylinder across its length into individual wrapped elements.

[0137] Example Ex42: The apparatus of any one of Examples Ex32 to Ex41 , wherein the web of crimped material comprises reconstituted tobacco.

[0138] Example Ex43: The apparatus of any one of Examples Ex32 to Ex41 , wherein the web of crimped material comprises tobacco cast leaf.

[0139] Example Ex44: The apparatus of any one of Examples Ex32 to Ex41 , wherein the web of crimped material comprises paper.

[0140] Example Ex45: The apparatus of any one of Examples Ex32 to Ex41 , wherein the web of crimped material comprises cellulose acetate tow.

[0141] Example Ex46: The apparatus of any one of Examples Ex32 to Ex41 , wherein the web of crimped material comprises polylactic acid, PLA.

[0142] Example Ex47: A guide device for shaping a web of crimped material, the guide device comprising a body portion with a forward end, a rearward end, a solid bottom surface, first and second solid side surfaces, and a partially open top surface, wherein the body portion comprises a partially cylindrical bore having a longitudinal axis extending from the rearward end to the forward end, the partially cylindrical bore having a curved longitudinal wall, and a front surface sloping downwardly from the partially open top surface to the bottom surface in a direction towards the forward end, the front surface and the side surfaces flaring outwardly from the partially open top surface towards the bottom surface so as to define a guide surface configured to feed the web of crimped material smoothly into the partially cylindrical bore such that the web of crimped material transitions from a substantially flat configuration to a curved configuration conformed to the curved longitudinal wall of the partially cylindrical bore as the web of crimped material passes through the guide device from the forward end to the rearward end. Example Ex48: The guide device of Example Ex47, wherein the guide surface has a triangular shape that is wider at the bottom than at the top.

[0143] Example Ex49: The guide device of Example Ex47 or Ex48, wherein a bottom edge of the guide surface is provided with a tongue portion that curves downwardly.

[0144] Example Ex50: The guide device of Example Ex49, wherein an upper surface of the tongue portion is provided with a knurled or patterned surface to reduce friction between the web of crimped material and the tongue portion.

[0145] Example Ex51 : The guide device of any one of Examples Ex47 to Ex50, wherein the guide surface is provided with a knurled or patterned surface to reduce friction between the web of crimped material and the guide surface.

[0146] Example Ex52: The guide device of any one of Examples Ex47 to Ex51 , wherein the partially cylindrical bore has a substantially constant diameter along the longitudinal axis.

[0147] Example Ex53: The guide device of any one of Examples Ex47 to Ex51 , wherein the partially cylindrical bore has a diameter that progressively decreases from the forward end to the rearward end along the longitudinal axis.

[0148] Example Ex54: The guide device of any one of Examples Ex47 to Ex53, wherein the partially open top surface slopes downwardly from the rearward end towards the forward end along the longitudinal axis.

[0149] Example Ex55: The guide device of Example Ex54, wherein the partially open top surface slopes downwardly from the rearward end towards the forward end at an angle smaller than an angle by which the front surface slopes downwardly from the top surface to the bottom surface.

[0150] Example Ex56: The guide device of any one of Examples Ex47 to Ex55, wherein the partially open top surface has an elongate open slot extending from the rearward end to the forward end.

[0151] Example Ex57: The guide device of Example Ex56 depending from Example Ex54 or Example Ex55, wherein the elongate open slot has a width that progressively increases from the rearward end towards the forward end.

[0152] Example Ex58: The guide device of any one of Examples Ex47 to Ex57, wherein the guide device is made of metal, preferably wherein the guide device is made of steel, more preferably wherein the guide device is made of stainless steel.

[0153] Example Ex59: The guide device of any one of Examples Ex47 to Ex58, in combination with an applicator configured to apply an additive onto the web of crimped material.

[0154] Example Ex60: The guide device of Example Ex59, wherein the applicator comprises at least one spray nozzle disposed at an open part of the partially open top surface.

[0155] Example Ex61 : The guide device of Example Ex59, wherein the applicator comprises at least one spray nozzle disposed at the forward end of the guide device where the guide surface transitions into the partially cylindrical bore. Example Ex62: The guide device of any one of Examples Ex59 to Ex61 , wherein the applicator is configured to spray the additive onto the web of crimped material while the web of crimped material is in the curved configuration.

[0156] Example Ex63: The guide device of any one of Examples Ex47 to Ex62, in combination with a roller disposed adjacent and substantially parallel to a bottom edge of the guide surface, wherein the roller is configured to direct the web of crimped material onto the guide surface.

[0157] Example Ex64: The apparatus of any one of Examples Ex32 to Ex46, wherein the at least one deforming element comprises the guide device of any one of Examples Ex47 to Ex63.

[0158] Examples will now be further described with reference to the figures in which:

[0159] Figure 1 shows, in schematic form, a known apparatus for forming filter rods from cellulose acetate tow;

[0160] Figure 2 shows, in schematic form, a forming funnel of the apparatus of Figure 1 ;

[0161] Figure 3 shows, in schematic form, a cross-section “a” through Figure 1 ;

[0162] Figure 4 shows, in schematic form, a cross-section “b” through Figure 1 ;

[0163] Figure 5 shows, in schematic form, a known apparatus for applying additive to a web of crimped material and wrapping the web of crimped material to form a rod;

[0164] Figure 6 shows, in schematic form, a pair of crimping rollers of the apparatus of Figure 5;

[0165] Figure 7 shows, in schematic form, a crimped web of material formed by the crimping rollers of Figure 6;

[0166] Figure 8 shows, in schematic form, an uncrimped web of material being fed between the crimping rollers of Figure 6;

[0167] Figure 9 shows, in schematic form, a crimped web of material being output from between the crimping rollers of Figure 6;

[0168] Figure 10 shows, in schematic form, a star and ring tool of the apparatus of Figure 5;

[0169] Figure 11 shows, in schematic form, the star and ring tool of Figure 10 with a web of crimped material passing over the star and ring tool;

[0170] Figures 12 to 14 show, in schematic form, the application of additive to a convex upper surface of a web of material in the apparatus of Figure 5;

[0171] Figure 15 shows, in schematic form, a cross-section through a wrapped rod of a web of crimped material made by the apparatus of Figure 5;

[0172] Figure 16 shows, in schematic form, an apparatus for applying additive to a web of crimped material and wrapping the web of crimped material to form a rod, according to an embodiment of the present invention;

[0173] Figure 17 shows, in schematic form, a web conveying guide according to an embodiment of the present invention;

[0174] Figures 18 to 23 show, in schematic form, a web conveying guide according to another embodiment of the present invention; Figure 24 shows, in schematic form, the web conveying guide of Figures 18 to 23 in combination with an additive applicator;

[0175] Figure 25 shows, in schematic form, a spray pattern of an additive applicator;

[0176] Figure 26 shows, in schematic form, cross-section “d” through Figure 24;

[0177] Figure 27 shows, in schematic form, cross-section “e” through Figure 24;

[0178] Figure 28 shows, in schematic form, cross-section “f” through Figure 24;

[0179] Figure 29 shows, in schematic form, cross-section “g” through Figure 24;

[0180] Figure 30 shows, in schematic form, a star and ring tool of the apparatus of Figure 16;

[0181] Figures 31 and 32 show, in schematic form, the application of additive to a concave upper surface of a web of material in the apparatus of any one of Figures 18 to 29; and

[0182] Figure 33 shows, in schematic form, a cross-section through a wrapped rod of a web of crimped material made by the apparatus of any one of Figures 18 to 29.

[0183] Referring now to Figure 16, there is shown an apparatus for applying additive 205 to a web of crimped material 145 and wrapping the web of crimped material to form a rod 200. The apparatus is broadly similar to the apparatus shown in Figure 5, but with important modifications to enable the proper distribution and convenient addition of additive to a web of crimped material 145 prior to formation of a continuous rod 200. As in Figure 5, a material web 140 (which may be reconstituted tobacco, tobacco cast leaf, paper, cellulose acetate tow, PLA, or another suitable material) is unwound from a bobbin 141 and passed between a pair of crimping rollers 502, 503 so as to form a web of crimped material 145. The material web 140 may have a width of 60 millimetres to 300 millimetres, preferably 80 millimetres to 200 millimetres, most preferably 100 millimetres to 150 millimetres. The crimping rollers 502, 503 preferably have a width (measured along their axes of rotation) greater than the width of the material web 140. The circumferential surfaces of the crimping rollers 502, 503, at their closed points, may be spaced from each other by 0.1 to 2 millimetres, preferably 0.2 to 0.9 millimetres, most preferably 0.3 to 0.6 millimetres. The web of crimped material 145 may then be passed over guide rollers 123, 124 and across a guide surface of a guide device 100, described in more detail hereinbelow. The guide rollers 123, 124 help to guide the web of crimped material 145 smoothly onto the guide surface of the guide device 100. The guide rollers 123, 124 may have circumferential surfaces formed of an abrasionresistant material, for example carbon fibre material. The guide rollers 123, 124 may have a vertical spacing from each other of 100 millimetres to 300 millimetres, preferably 150 millimetres to 250 millimetres, most preferably 180 millimetres to 220 millimetres. The web of crimped material 145 is deformed from a substantially flat planar configuration across its width into a curved concave configuration across its width by the guide device 100, and additive 205 is applied by an applicator 121 , for example by way of spraying, onto the concave surface of the web of crimped material 145. The applicator 121 can be positioned closer to the web of crimped material 145 on the guide device 100 than in prior art apparatuses, for example at a spacing of around 100 millimetres, due to the concave curvature of the web of crimped material 145. This can help to reduce overspray and can promote more even application of the additive 205 across the surface of the web of crimped material 145. The after-cut chamber 120 may be provided with a base forming a drip tray, and a drain 122 may be provided in the base so as to allow any excess or oversprayed additive 205 to be removed from the after-cut chamber 120, thus avoiding unwanted build-up of additive 205 in the after-cut chamber 120.

[0184] The web of crimped material 145 then passes across an underside of a star and ring tool 510 and through a forming funnel 404. The forming funnel 404 gathers the web of crimped material 145 into a gathered web of crimped material 150. Because the additive 205 has been applied to the concave surface of the web of crimped material 145, the additive will tend to be more concentrated on an inside, rather than an outside, of the gathered web of crimped material 150 that is output from the forming funnel 404. The gathered web of crimped material 150 then travels through a garniture area where an endless garniture belt 416 is driven by garniture rollers 415 so as to travel across an upper surface of a garniture bed 417. The garniture belt 416 passes along a progressively deepening longitudinal groove in the garniture bed 417 at the top of the garniture area. Wrapping material 414, in the form of a band, is unwound from a bobbin 413 and travels along the garniture bed 417 on top of the garniture belt 416, with the gathered web of crimped material 145 on top the band of wrapping material 414. The garniture belt 416 and the band of wrapping material 414 are caused to wrap longitudinally around the gathered web of crimped material 145 as the garniture belt 416 travels along the progressively deepening groove towards a heating block 202, where the wrapping material 414 is sealed around the gathered web of crimped material 145 so as to form a continuous wrapped rod 200. The continuous wrapped rod 200 can then be cut into sections as required.

[0185] Figure 17 shows an alternative, simplified arrangement in which the web of crimped material 145 is caused to deform across its width to a curved configuration by way of passage through a first hoop 600. The first hoop 600 may be circular. The first hoop 600 may be elliptical. The first hoop 600 may be oval. The first hoop 600 may have a racetrack or stadium shape. A radius of curvature of the web of crimped material 145 may be controlled by adjusting an angle of the first hoop 600 relative to a direction of travel of the web of crimped material 145. An applicator 121 is configured to apply an additive (not shown in Figure 17) to a concave surface (in Figure 17, the upper surface) of the web of crimped material 145. Optionally, a second hoop 601 , similar to the first hoop 600, may be provided downstream of the first hoop 600, and this may help to stabilise the web of crimped material 145 before the web of crimped material 145 enters a forming funnel 404.

[0186] Figures 18 to 23 show different views of a guide device 100 suitable for implementation in the apparatus of Figure 16. The guide device 100 comprises a body portion with a forward end 111 , a rearward end 112, a solid bottom surface 113, first and second solid side surfaces 114, 116, and a partially open top surface 117. The body portion comprises a partially cylindrical bore 105 having a longitudinal axis extending from the rearward 112 end to the forward end 111. The partially cylindrical bore 105 has a curved longitudinal wall. The body portion further comprises a front surface sloping downwardly from the partially open top surface 117 to the bottom surface 113 in a direction towards the forward end 111 , the front surface and the side surfaces 114, 116 flaring outwardly from the partially open top surface 117 towards the bottom surface 113 so as to define a guide surface 110. The guide surface 110 is configured to feed the web of crimped material 145 (not shown in Figures 18 to 23) smoothly into the partially cylindrical bore 105 such that the web of crimped material 145 transitions from a substantially flat configuration to a curved configuration conformed to the curved longitudinal wall of the partially cylindrical bore 105 as the web of crimped material 145 passes through the guide device 100 from the forward end 111 to the rearward end 112. In this way, the web of crimped material 145 transitions from a substantially flat planar configuration to a substantially semi-cylindrical configuration as the web of crimped material 145 traverses the guide device 100, facilitating efficient application of additive to the concave surface of the web of crimped material 145 by way of the applicator 121 .

[0187] The guide surface 110 has a triangular shape that is wider at the bottom than at the top. A bottom edge of the guide surface 110 may be provided with a tongue portion 115 that curves downwardly.

[0188] An upper surface of the tongue portion 115 may be provided with a knurled or patterned surface as shown in Figure 20 so as to reduce friction between the web of crimped material 145 and the tongue portion 115. The guide surface 110 may be provided with a knurled or patterned surface as shown in Figure 20 to reduce friction between the web of crimped material 145 and the guide surface 110. This can help to enhance production speeds by allowing the web of crimped material 145 to travel across the guide surface 110 at a speed in a range of 50 metres per minute to 500 metres per minute, preferably 80 metres per minute to 120 metres per minute.

[0189] The partially cylindrical bore 105 may have a substantially constant diameter along the longitudinal axis. Alternatively, the partially cylindrical bore 105 may have a diameter that progressively decreases from the forward end 111 to the rearward end 112 along the longitudinal axis.

[0190] The partially open top surface 117 may slope downwardly from the rearward end 112 towards the forward end 111 along the longitudinal axis. The partially open top surface 117 may slope downwardly from the rearward end 112 towards the forward end 111 at an angle smaller than an angle by which the front surface slopes downwardly from the top surface 117 to the bottom surface 113. As shown in Figure 20, the partially open top surface 117 may have an elongate open slot 118 extending from the rearward end 112 to the forward end 111. The elongate open slot 118 may have a width that progressively increases from the rearward end 112 towards the forward end 111.

[0191] The guide device 100 may be made of metal, preferably steel, more preferably stainless steel.

[0192] Figure 23 shows a plan view of an exemplary guide device 100 with indicative dimensions.

[0193] The width L5 of the elongate open slot 118 at its widest point may be from 25 millimetres to 200 millimetres, preferably 50 millimetres to 150 millimetres, most preferably 75 millimetres to 85 millimetres.

[0194] The length L6 of the partially open top surface 117 from the rearward end 112 to the top of the guide surface 110 may be from 100 millimetres to 400 millimetres, preferably 150 millimetres to 300 millimetres, most preferably 175 millimetres to 225 millimetres.

[0195] The overall length L7 of the guide device 100 from the rearward end 112 to the forward end 111 may be from 200 millimetres to 700 millimetres, preferably 400 millimetres to 500 millimetres, most preferably 425 millimetres to 475 millimetres.

[0196] The width L8 of the bottom edge of the guide surface 110 may be from 75 millimetres to 350 millimetres, preferably 190 millimetres to 270 millimetres, most preferably 210 millimetres to 250 millimetres.

[0197] Figure 24 shows a plan view of a guide device 100 in combination with an applicator 121. The applicator 121 is positioned over or in the elongate open slot 118 towards the forward end 111 of the guide device. In this position, the applicator 121 is able to apply additive to a concave surface of a web of crimped material 145 as it enters the longitudinal bore 105 of the guide device 100. There is also shown the material web 140 being unwound from the material web bobbin 141 and passing between crimping rollers 502 to form the web of crimped material 145. The web of crimped material 145 enters the after-cut chamber 120 and passes over rollers 123 before sliding across the tongue portion 115 and guide surface 110 of the guide device 100.

[0198] Figure 25 shows an exemplary spray pattern of an applicator 121 configured to spray additive 205 onto a concave curved surface of a web of crimped material 145. The spray pattern extends in both width and length directions across the concave curved surface of the web of crimped material 145. In the illustrated example, the spray pattern has a star configuration, spraying along eight rays from a central point. In other examples, the spray pattern may have four, six, ten or twelve rays, or any number of rays as appropriate. Other spray patterns may be used.

[0199] Figures 26 to 29 are cross-sectional views taken along lines “d”, “e”, “f” and “g”, respectively, of Figure 24, illustrating the progressively increasing concave curvature of the web of crimped material 145 as the web of crimped material 145 passes over and through the guide device 100. Figure 28 shows the applicator 121 spraying additive 205 onto the concave surface of the web of crimped material 145 at line “f” of Figure 24.

[0200] Figure 30 shows the star and ring tool 510 of Figure 16 in more detail. The star and ring tool 510, comprising a star portion 512 and a ring portion 511 , is similar to the star and ring tool 510 shown in Figures 10 and 11. However, in the apparatus of Figure 16, the web of crimped material 145, in its curved configuration, passes under, rather than over, the star and ring tool 510.

[0201] Figures 31 and 32 illustrate, in schematic form, the application by an applicator 121 of additive 205 to a concave surface of a web of crimped material 145. Figures 31 and 32 may be contrasted with the prior art arrangements shown in Figures 13 and 14. In addition to reducing the risk of overspray, the application of additive 205 to the concave surface of the web of crimped material 145 means that the surface of the web of crimped material 145 that has been provided with additive 205, after gathering and wrapping, will form an inner part of the resulting rod-shaped consumable 200, as shown in Figure 33. Because the additive 205 is applied to the concave surface of the web of crimped material 145, there will tend to be a greater concentration of additive 205 on inner surfaces of the gathered and formed web of crimped material 150 after passage through the forming funnel 404 and the garniture area. Accordingly, the resulting rod-shaped consumable 200 will comprise a rod-shaped core of gathered and formed crimped material 150 within a circumferential wrapper 414, with an outer annulus 153 with a low or substantially no concentration of additive 205 and an inner core 154 with a higher concentration of additive 205. The lower concentration of additive 205 in the outer annulus 153 means that there is less risk of additive migration through the circumferential wrapper 414, and a reduction or elimination of unwanted staining.

[0202] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 5% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

1. A method for applying an additive to a web of corrugated material for use in an aerosol generating product, according to which the corrugated material sheet has a width and a length; the web of corrugated material is moved along a path substantially parallel to the length of the web of corrugated material at any given point along the path; the web of corrugated material is deformed along at least a portion of a path across the width of the web of corrugated material from a substantially flat configuration to a curved configuration; and The additive is applied to the concave surface of the corrugated material web in a curved configuration.

2. The method according to claim 1, in which the concave surface of the corrugated material web faces upward, and the additive is applied from above.

3. The method according to claim 1 or 2, in which the web of corrugated material, after applying the additive, is further deformed into a rod or cylinder, wherein the concave surface faces inward.

4. A method according to any one of the preceding claims, wherein the web of corrugated material is fed through a guide device comprising a body portion with a front end, a rear end, a solid bottom surface, first and second solid side surfaces and a partially open top surface, wherein the body portion comprises a partially cylindrical opening having a longitudinal axis extending from the rear end to the front end, wherein the partially cylindrical opening has a curved longitudinal wall, and a front surface inclined downwardly from the top surface to the bottom surface in the direction of the front end, wherein the front surface and the side surfaces flare outwardly from the top surface in the direction of the bottom surface so as to form a guide surface, and wherein the web of corrugated material transitions from a substantially flat configuration at a lower edge of the guide surface to a curved configuration,corresponding to the longitudinal wall of the partially cylindrical opening when the web of corrugated material passes through the guide device from the front end and through the partially cylindrical opening to the rear end.

5. The method of claim 4, wherein the partially open upper surface is inclined downwardly from the rear end to the front end at an angle less than the angle at which the front surface is inclined downwardly from the upper surface to the lower surface.

6. The method of claim 4 or 5, wherein the partially open upper surface has an elongated open groove extending from the rear end to the front end.

7. The method according to any one of paragraphs 4-6, wherein the additive is applied to the web of corrugated material using an applicator, and wherein the applicator comprises at least one spray nozzle located at the front end of the guide device, in which the guide surface transitions into a partially cylindrical opening.

8. A device for applying an additive to a web of corrugated material for use in an aerosol generating product, the device comprising a plurality of guides for guiding a web of corrugated material along a path, wherein the web of material has a width and a length, and the path is substantially parallel to the length of the web of corrugated material at any given point along the path; at least one deforming element configured to deform the web of corrugated material along at least a portion of a path across the width of the web of corrugated material from a substantially flat configuration to a curved configuration; and an applicator configured to apply an additive to the concave surface of a web of corrugated material in a curved configuration.

9. The device according to claim 8, in which at least one deforming element is configured to deform the web of corrugated material so that the concave surface of the web of corrugated material faces upward, and wherein the applicator is configured to apply the additive from above.

10. A guide device for forming a web of corrugated material, wherein the guide device comprises a body portion with a front end, a rear end, a solid bottom surface, first and second solid side surfaces and a partially open top surface, wherein the body portion comprises a partially cylindrical opening having a longitudinal axis extending from the rear end to the front end, wherein the partially cylindrical opening has a curved longitudinal wall, and a front surface inclined downward from the partially open top surface to the bottom surface in the direction of the front end, wherein the front surface and the side surfaces expand outward from the partially open top surface to the bottom surface so as to form a guide surface configured to smoothly feed the web of corrugated material into the partially cylindrical opening in such a way,that the web of corrugated material transitions from a substantially flat configuration to a curved configuration corresponding to the curved longitudinal wall of the partially cylindrical opening as the web of corrugated material passes through the guide device from the front end to the rear end.

11. The guide device of claim 10, wherein the partially open upper surface is inclined downwardly from the rear end to the front end along the longitudinal axis at an angle less than the angle by which the front surface is inclined downwardly from the upper surface to the lower surface.

12. The guide device according to item 10 or 11 in combination with an applicator designed to apply an additive to the web of corrugated material.

13. The guide device according to claim 12, wherein the applicator comprises at least one spray nozzle located at the front end of the guide device, according to which the guide surface transitions into a partially cylindrical opening.

14. A guide device according to claim 12 or 13, wherein the applicator is configured to spray the additive onto the web of corrugated material when the web of corrugated material is in a curved configuration.

15. The device according to claim 8 or 9, in which at least one deforming element comprises a guide device according to any one of claims 10-14.