Apparatus and method for producing a sheet of aerosol-generating substrate for aerosol-generating articles

Abstract

An apparatus for producing a sheet of aerosol-generating substrate for an aerosol-generating article, the apparatus comprising: a dough mixer (2) configured for kneading a mixture with a recipe and water to form a dough (D); a dough sheeter (4) configured to make a continuous dough sheet (7) from the dough (D); a couple of flattening rollers placed downstream of the dough sheeter (4), having lateral surfaces facing each other and delimiting a gap for the passage of the continuous dough sheet (7) to be flattened. A spreader roller (16) is placed upstream of the couple of flattening rollers and is configured to support a portion of the continuous dough sheet (7) on an upper part of a lateral surface of the spreader roller (16). Support elements (18), each coupled to one of two opposite axial ends of the spreader roller (16), are configured to allow movements of the axial ends under forces induced by the continuous dough sheet (7).

Description

[0001] APPARATUS AND METHOD FOR PRODUCING A SHEET OF AEROSOLGENERATING SUBSTRATE FOR AEROSOL-GENERATING ARTICLES

[0002] The present disclosure relates to an apparatus and to a method for producing a sheet of aerosol-generating substrate for aerosol-generating articles.

[0003] Aerosol-generating articles or heat-not-burn cigarettes, in which an aerosolgenerating substrate is heated rather than combusted, are known in the art. The aerosolgenerating substrate is for instance a sheet of reconstituted tobacco, a tobacco-free herbaceous or plant-based sheet or a plastic fibre-based sheet or a biodegradable fibrebased sheet. The sheet is gathered and enclosed in a wrapping to form a rod of aerosol generating substrate.

[0004] Typically, in such heated aerosol-generating articles, an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-generating substrate or material, which may be in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

[0005] A sheet of aerosol-generating substrate may be prepared by rolling methods or casting methods, depending on the amount of water used in the process. If the amount of water is low in the starting mixture, the sheet is usually obtained by rolling steps, because the mixture is like pasta or dough. To flatten this dough material to a constant thickness, the dough is processed through multiple sequential rolling steps until the desired thickness of the material is obtained.

[0006] For instance, document W02020058814A1 discloses a method for producing reconstituted tobacco wherein solid components of tobacco are comminuted to bring them to a particle size. The comminuted product thus obtained is mixed with water, at least one binding agent and at least one aerosol forming material until a mixture with a liquid content of about 35-40 percent is obtained. A mixture forming unit forms a plurality of portions of the mixture. From the portions of said mixture, a first lamination unit is configured to obtain a continuous strip and a series of further rolling passages through lamination rollers allow to obtain a strip having a substantially constant thickness. The strip is then dried to bring its liquid content to about 8-15 percent.

[0007] In this technical field, it would be desirable to improve the quality of sheets of aerosolgenerating substrate and thus of the aerosol-generating articles including these sheets. It would be desirable to improve the consistency of the properties through different sheets and also in a single sheet of aerosol-generating substrate.

[0008] Particularly, it would be desirable to manufacture sheets of aerosol-generating substrate for aerosol-generating articles as homogeneous as possible in terms of density and / or grammage.

[0009] It would also be desirable to have an apparatus and a method for producing a sheet of aerosol-generating substrate for aerosol-generating articles capable of manufacturing the sheets provided with the above qualities.

[0010] The present disclosure relates to an apparatus for producing a sheet of aerosolgenerating substrate for aerosol-generating articles. The apparatus may comprise a dough mixer configured for kneading a mixture with a recipe and water to form a dough. The apparatus comprises a dough sheeter, optionally calendering rollers, configured to make a continuous dough sheet from said dough. The apparatus comprises at least one couple of flattening rollers placed downstream of the dough sheeter with respect to a conveying direction of the continuous dough sheet, the flattening rollers having lateral surfaces facing each other and delimiting a gap for the passage of the continuous dough sheet to be flattened. The apparatus comprises at least one spreader roller placed upstream of the at least one couple of flattening rollers, at a greater height than the gap and rotatable about a main axis, wherein the spreader roller is configured to support a portion of the continuous dough sheet on an upper part of a lateral surface of said spreader roller. The apparatus further comprises support elements, each coupled to one of two opposite axial ends of the spreader roller. The support elements are configured to allow movements of the axial ends under forces induced by the continuous dough sheet.

[0011] The present disclosure also relates to a method for producing a sheet of aerosol generating substrate for aerosol-generating articles, wherein the method is carried out through an apparatus for producing a sheet of aerosol-generating substrate for aerosolgenerating articles. The apparatus may comprise a dough mixer configured for kneading a mixture with a recipe and water to form a dough. The apparatus comprises a dough sheeter, optionally calendering rollers, configured to make a continuous dough sheet from said dough. The apparatus comprises at least one couple of flattening rollers placed downstream of the dough sheeter with respect to a conveying direction of the continuous dough sheet, the flattening rollers having lateral surfaces facing each other and delimiting a gap for the passage of the continuous dough sheet to be flattened. The apparatus comprises at least one spreader roller placed upstream of the at least one couple of flattening rollers, at a greater height than the gap and rotatable about a main axis, wherein the spreader roller is configured to support a portion of the continuous dough sheet on an upper part of a lateral surface of said spreader roller. The apparatus further comprises support elements, each coupled to one of two opposite axial ends of the spreader roller. The support elements are configured to allow movements of the axial ends under forces induced by the continuous dough sheet.

[0012] The present disclosure also relates to a method for producing a sheet of aerosol generating substrate for aerosol-generating articles. The method may comprise: kneading a mixture with a recipe and water to form a dough. The method comprises: making a continuous dough sheet from said dough and advancing the continuous dough sheet along a conveying path. The method comprises: flattening the continuous dough sheet by running the continuous dough sheet through at least one couple of flattening rollers placed along the conveying path. The method further comprises: supporting a portion of the continuous dough sheet on an upper part of a lateral surface of at least one spreader roller placed upstream of the couple of flattening rollers, wherein axial ends of the spreader roller are movable under forces induced by the continuous dough sheet.

[0013] The present disclosure also relates to a process for manufacturing aerosol-generating article components.

[0014] The process comprises: producing the sheet of aerosol-generating substrate for aerosol-generating articles through the method for producing a sheet of aerosol generating substrate for aerosol-generating articles. The method may comprise: kneading a mixture with a recipe and water to form a dough. The method comprises: making a continuous dough sheet from said dough and advancing the continuous dough sheet along a conveying path. The method comprises: flattening the continuous dough sheet by running the continuous dough sheet through at least one couple of flattening rollers placed along the conveying path. The method further comprises: supporting a portion of the continuous dough sheet on an upper part of a lateral surface of at least one spreader roller placed upstream of the couple of flattening rollers, wherein axial ends of the spreader roller are movable under forces induced by the continuous dough sheet.

[0015] The process for manufacturing aerosol-generating article components may comprise: gathering the sheet of aerosol-generating substrate and wrapping the gathered sheet of aerosol-generating substrate in a wrapper to form a continuous rod. The process for manufacturing aerosol-generating articles component may comprise: cutting the continuous rod into a plurality of aerosol-generating article components each having a rod shape, each aerosol-generating article component comprising a gathered sheet formed from a cut portion of the sheet of aerosol-generating substrate. The present disclosure also relates to an aerosol-generating article comprising at least one aerosol-generating article component made through said process for manufacturing aerosol-generating article components.

[0016] The inventor found that the movements of the spreader roller, caused by the weight and motion of the continuous dough sheet and allowed by the support elements, prevents or at least decreases accumulation (buffering) of material of said continuous dough sheet at the gap delimited between the flattening rollers.

[0017] The inventor found that said movements of the spreader roller ensures a continuous and homogenous infeed of the dough at the gap of the flattening rollers.

[0018] The inventor found that preventing mass accumulation at said gap allows to guarantee uniform density and grammage of the final sheet after lamination through one or more couple of flattening rollers. The inventor found that preventing mass accumulation at said gap allows to avoid formation of an additional layer of dough on the laminated sheet. Indeed, the amount and position of said additional layer would be indetermined and not controlled and would create density variation on the entire surface of the laminated sheet.

[0019] The inventor found that uniform density and grammage is ensured both longitudinally along the continuous dough sheet and transversally across said continuous dough sheet.

[0020] According to some embodiments, the axial ends are movable independently of each other along directions perpendicular to the main axis. The axial ends may be movable independently of each other along vertical directions. The axial ends may be movable independently of each other along horizontal directions. The support elements may be configured to allow movements of the axial ends independently of each other along directions perpendicular to the main axis. The support elements may be configured to allow movements of the axial ends along vertical directions. The support elements may be configured to allow movements of the axial ends independently of each other along the vertical directions. The support elements may be configured to allow a main axis of the spreader roller to translate and / or to tilt. The support elements may be configured to allow movements of the axial ends along horizontal directions. The support elements may be configured to allow movements of the axial ends independently of each other along the horizontal directions perpendicular to the main axis.

[0021] The inventor found that the movements disclosed above of the axial ends allow the spreader roller to tilt and to ensure the homogenous infeed of the dough even when the accumulation is not evenly distributed across a width of the gap and / orwhen a misalignment between the continuous dough sheet and the gap occurs. This misalignment may be due to variations in dough thickness, unevenness of a conveyor belt transporting the continuous dough sheet upstream of the flattening rollers, or fluctuations in the speed of the flattening rollers.

[0022] The at least one spreader roller translates and / or tilts under the forces induced by the continuous dough sheet.

[0023] Elastic forces may retain the axial ends of the at least one spreader roller and oppose the movements of said axial ends. The elastic forces may be directed upwards. The elastic forces may be adjustable. The elastic forces may be generated by springs. A stiffness and a pre-load of the springs may be adjustable.

[0024] According to some embodiments, each support element comprises at least one spring. The at least one spring may be a coil spring. The at least one spring may be a compression spring or an extension spring. According to some embodiments, each support comprises an oil damper.

[0025] The inventor found that the elastic force exerted by the spring allows the spreader roller to move and to adapt its position as a function of the forces exerted at each instant by the continuous dough sheet.

[0026] According to some embodiments, the at least one spring exerts an elastic force directed upwards and optionally along a vertical direction. Indeed, the main forces from the continuous dough sheet are directed mainly downward.

[0027] According to some embodiments, the at least one spring is pre-loaded. The pre-load of the at least one spring may be adjustable. The apparatus may comprise a device for adjusting the pre-load of the at least one spring. A stiffness of the at least one spring may be adjustable.

[0028] The inventor found that the pre-load and / or stiffness may be adjusted according to the features of the continuous dough sheet. The spring is deformed when the force exerted by the continuous dough sheet (mainly due to weight) overcomes the pre-load force.

[0029] According to some embodiments, an average height of the spreader roller is adjustable. An average height of each axial end may be adjustable.

[0030] The inventor found that an inlet angle of the continuous dough sheet between the flattening rollers may be properly set by adjusting the average height.

[0031] According to some embodiments, a support frame is located above the spreader roller. Each axial end may be linked to the support frame through the respective support element. Each axial end may be hanging from the support frame. The inventor found that, through this structure, the spreader roller is elastically suspended and also the portion of the continuous dough sheet on the upper part of the lateral surface of said spreader roller is elastically suspended. According to some embodiments, the spreader roller is free to rotate about the main axis. The spreader roller rotates idly about the main axis when dragged into rotation by the continuous sheet.

[0032] According to some embodiments, the lateral surface of the spreader roller is made of metal, optionally of stainless steel or aluminum alloy. According to other embodiments, the lateral surface of the spreader roller is made of polymeric material, optionally of Polyetheretherketone (PEEK). The inventor found that non-stick materials, like Polyetheretherketone or aluminum alloy, prevent sticking of the continuous dough sheet on the spreader roller and decrease the forces transferred from the sheet to the roller.

[0033] According to some embodiments, at least one actuator is connected to the support elements and a control unit operatively connected to the actuator.

[0034] A concave bend facing upwards may be formed by the continuous dough sheet upstream of the spreader roller and it is provided for detecting a depth of the concave bend and adjusting the support elements as a function of said depth.

[0035] According to some embodiments, a sensor is operatively connected to the control unit. The sensor is positioned and configured to detect a depth of a concave bend facing upwards and formed by the continuous dough sheet upstream of the spreader roller.

[0036] According to some embodiments, adjusting the support elements comprises: adjusting the elastic forces and / or the average height of the spreader roller.

[0037] The control unit may be configured to carry out the following procedure: receiving from the sensor a signal correlated to the depth of the concave bend, controlling the actuator to adjust the support elements as a function of said signal.

[0038] Detecting the depth of the concave bend and adjusting the support elements are performed continuously or at regular intervals, as a loop. According to some embodiments, the procedure is a control loop performed continuously or at regular intervals.

[0039] The inventor found that this kind of control allows to adjust in real-time the position of the spreader roller and to further improve the homogeneity of density and / or grammage of the continuous dough sheet.

[0040] According to some embodiments, the sensor is a laser distance sensor. The sensor may be placed upstream of the spreader roller and facing downwards.

[0041] According to some embodiments, adjusting the support elements comprises: adjusting the pre-load of the springs. Adjusting the pre-load of the springs may comprise: adjusting a length of the springs.

[0042] Adjusting the pre-load of the springs may comprise: adjusting an average height of the spreader roller. The depth of the concave bend depends on the thickness, weight, and elasticity of the continuous dough sheet. A greater depth means that the continuous dough sheet is more flexible and prone to bending, while a lower depth means that the continuous dough sheet is more rigid and flat. The average height of the spreader roller determines how much pressure and tension are applied to the continuous dough sheet by the flattening rollers, which affects the final shape and quality of the product.

[0043] Adjusting the elastic forces and / or the average height of the spreader roller may comprise: adjusting the pre-load of the springs. The pre-load may be adjusted as a function of a weight or grammage of the continuous dough sheet.

[0044] Flattening the continuous dough sheet may be carried out in sequential steps by running the continuous dough sheet through a plurality of couples of flattening rollers arranged one after the other along the conveying direction. According to some embodiments, the at least one couple of flattening rollers comprises a plurality of couples of flattening rollers arranged one after the other along the conveying direction. The at least one spreader roller may be placed upstream of one or more of the couples of flattening rollers. The spreader roller may be placed only upstream of a last couple of flattening rollers. The at least one spreader roller may comprise a plurality of spreader rollers, each placed upstream of one of the couples of flattening rollers. According to some embodiments, it is provided for supporting the portion of the continuous dough sheet on the upper part of the lateral surface of at least one spreader roller placed upstream of one or more of the couples of flattening rollers.

[0045] The at least one spreader roller may have an external diameter from 10 mm to 30 mm.

[0046] According to some embodiments, a moving conveyor, for instance a belt conveyor, is placed between the dough sheeter and the at least one spreader roller and is configured to convey the continuous dough sheet towards the flattening rollers.

[0047] The inventor found that the spreader roller placed between the dough sheeter and the spreader roller allows to compensate for misalignment due to unevenness of the moving conveyor.

[0048] According to some embodiments, it is provided for drying the flattened sheet. A dryer, optionally an oven, may be arranged downstream of the at least one couple of flattening rollers and is configured to dry the flattened continuous dough sheet.

[0049] According to some embodiments, the recipe comprises as ingredients vegetable and / or alkaloid particles, a binder and an aerosol forming agent. An amount of water in the mixture may be from 25 percent to 35 percent on wet weight basis. A thickness of the continuous dough sheet upstream of the at least one couple of flattening rollers, or of the plurality of couples of flattening rollers, may be from 2 mm to 20 mm. A final thickness of the continuous dough sheet downstream of the at least one couple of flattening rollers, or of the plurality of couples of flattening rollers, may be from 0.15 mm to 0.35 mm.

[0050] As used in the present description, the term “recipe” means a group of ingredients without any limitation concerning the order and the timing in which they are combined with each other and / or with water.

[0051] As used in the present description, the term “dough” means a mixture that is stiff enough to be kneaded or rolled out, as opposed to a “slurry” which is a watery mixture of insoluble matter with a water content so high (e.g. 70 percent - 80 percent) that cannot be kneaded or rolled out.

[0052] As used in the present description, the terms “upstream” and “downstream” are used to describe the relative positions of components, or portions of components, of the apparatus in relation to the direction in which a material or materials passes through the apparatus along a given path.

[0053] 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.

[0054] EX1. An apparatus for producing a sheet of aerosol-generating substrate for aerosol-generating articles, the apparatus comprising: a dough mixer configured for kneading a mixture with a recipe and water to form a dough; a dough sheeter, optionally calendering rollers, configured to make a continuous dough sheet from said dough; at least one couple of flattening rollers placed downstream of the dough sheeter with respect to a conveying direction of the continuous dough sheet, the flattening rollers having lateral surfaces facing each other and delimiting a gap for the passage of the continuous dough sheet to be flattened; at least one spreader roller placed upstream of the at least one couple of flattening rollers, at a greater height than the gap and rotatable about a main axis; the spreader roller being configured to support a portion of the continuous dough sheet on an upper part of a lateral surface of said spreader roller; support elements each coupled to one of two opposite axial ends of the spreader roller; wherein the support elements are configured to allow movements of the axial ends under forces induced by the continuous dough sheet. EX2. The apparatus according to EX1 , wherein the support elements are configured to allow movements of the axial ends independently of each other along directions perpendicular to the main axis.

[0055] EX3. The apparatus according to EX1 or EX2, wherein the support elements are configured to allow movements of the axial ends along vertical directions.

[0056] EX4. The apparatus according to EX3, wherein the support elements are configured to allow movements of the axial ends independently of each other along the vertical directions.

[0057] EX5. The apparatus according to any of EX1 to EX4, wherein the support elements are configured to allow a main axis of the spreader roller to translate and / or to tilt.

[0058] EX6. The apparatus according to any of EX1 to EX5, wherein the support elements are configured to allow movements of the axial ends along horizontal directions.

[0059] EX7. The apparatus according to EX6, wherein the support elements are configured to allow movements of the axial ends independently of each other along the horizontal directions perpendicular to the main axis.

[0060] EX8. The apparatus according to any of EX1 to EX7, wherein each support element comprises at least one spring; optionally the at least one spring is a coil spring; optionally the at least one spring is a compression spring; optionally the at least one spring is an extension spring; optionally each support element comprises an oil damper.

[0061] EX9. The apparatus according to EX8, wherein the at least one spring exerts an elastic force directed upwards and optionally along a vertical direction.

[0062] EX10. The apparatus according to EX8 or EX9, wherein the at least one spring is pre-loaded.

[0063] EX11. The apparatus according to EX10, wherein a pre-load of the at least one spring is adjustable; optionally wherein the apparatus comprises a device for adjusting the pre-load of the at least one spring; optionally a stiffness of the at least one spring is adjustable.

[0064] EX12. The apparatus according to any of EX1 to EX11 , wherein an average height of the spreader roller is adjustable.

[0065] EX13. The apparatus according to any of EX1 to EX12, wherein an average height of each axial end is adjustable.

[0066] EX14. The apparatus according to any of EX1 to EX13, comprising a support frame located above the spreader roller.

[0067] EX15. The apparatus according to EX14, wherein each axial end is linked to the support frame through the respective support element. EX16. The apparatus according to EX14 or EX15, wherein each axial end is hanging from the support frame.

[0068] EX17. The apparatus according to any of EX1 to EX16, wherein the spreader roller is free to rotate about the main axis, i.e. the spreader roller rotates idly about the main axis.

[0069] EX18. The apparatus according to any of EX1 to EX17, wherein the lateral surface of the spreader roller is made of metal, optionally of stainless steel or aluminum alloy.

[0070] EX19. The apparatus according to any of EX1 to EX17, wherein the lateral surface of the spreader roller is made of polymeric material, optionally of Polyetheretherketone (PEEK).

[0071] EX20. The apparatus according to any of EX1 to EX19, comprising: at least one actuator connected to the support elements, a control unit operatively connected to the actuator.

[0072] EX21. The apparatus according to EX20, comprising a sensor operatively connected to the control unit.

[0073] EX22. The apparatus according to EX21 , wherein the sensor is positioned and configured to detect a depth of a concave bend facing upwards and formed by the continuous dough sheet upstream of the spreader roller.

[0074] EX23. The apparatus according to EX22, wherein the control unit is configured to carry out the following procedure: receiving from the sensor a signal correlated to the depth of the concave bend, controlling the actuator to adjust the support elements as a function of said signal.

[0075] EX24. The apparatus according to any of EX21 to EX23, wherein the sensor is a laser distance sensor.

[0076] EX25. The apparatus according to any of EX21 to EX24, wherein the sensor is placed upstream of the spreader roller and facing downwards.

[0077] EX26. The apparatus according to any of EX20 to EX25 when any of EX12 to EX20 is according to EX11 , wherein adjusting the support elements comprises: adjusting the preload of the springs.

[0078] EX27. The apparatus according to EX26, wherein adjusting the pre-load of the springs comprises: adjusting a length of the springs.

[0079] EX28. The apparatus according to EX26 or EX27, wherein adjusting the pre-load of the springs comprises: adjusting an average height of the spreader roller.

[0080] EX29. The apparatus according to EX23 or to any of EX24 to EX28 when according to EX23, wherein adjusting the support elements comprises: adjusting the average height of spreader roller. EX30. The apparatus according to EX23 or EX29 or according to any of EX24 to EX28 when according to EX23, wherein the procedure is a control loop performed continuously or at regular intervals.

[0081] EX31 . The apparatus according any of EX1 to EX30, wherein the at least one couple of flattening rollers comprises a plurality of couples of flattening rollers arranged one after the other along the conveying direction.

[0082] EX32. The apparatus according to EX31 , wherein the at least one spreader roller is placed upstream of one or more of the couples of flattening rollers; optionally the spreader roller is placed only upstream of a last couple of flattening rollers.

[0083] EX33. The apparatus according to EX31 or EX32, wherein the at least one spreader roller comprises a plurality of spreader rollers, each placed upstream of one of the couples of flattening rollers.

[0084] EX34. The apparatus according to any of EX1 to EX33, wherein the at least one spreader roller has an external diameter from 10 mm to 30 mm.

[0085] EX35. The apparatus according to any of EX1 to EX34, further comprising a dryer, optionally an oven, arranged downstream of the at least one couple of flattening rollers and configured to dry the flattened continuous dough sheet.

[0086] EX36. The apparatus according to any of EX1 to EX35, further comprising a moving conveyor, optionally a belt conveyor, placed between the dough sheeter and the at least one spreader roller and configured to convey the continuous dough sheet towards the flattening rollers.

[0087] EX37. A method for producing a sheet of aerosol generating substrate for aerosolgenerating articles, the method being carried out through the apparatus according to any of EX1 to EX36.

[0088] EX38. A method for producing a sheet of aerosol-generating substrate for aerosolgenerating articles, the method comprising: kneading a mixture with a recipe and water to form a dough; making a continuous dough sheet from said dough and advancing the continuous dough sheet along a conveying path; flattening the continuous dough sheet by running the continuous dough sheet through at least one couple of flattening rollers placed along the conveying path; wherein the method further comprises: supporting a portion of the continuous dough sheet on an upper part of a lateral surface of at least one spreader roller placed upstream of the couple of flattening rollers, wherein axial ends of the spreader roller are movable under forces induced by the continuous dough sheet. EX39. The method according to EX38, the method being carried out through the apparatus according to any of EX1 to EX35.

[0089] EX40. The method according to any of EX37 to EX39, wherein the axial ends are movable independently of each other along directions perpendicular to the main axis.

[0090] EX41 . The method according to any of EX37 to EX40, wherein the axial ends are movable independently of each other along vertical directions.

[0091] EX42. The method according to any of EX37 to EX41 , wherein the axial ends are movable independently of each other along horizontal directions.

[0092] EX43. The method according to any of EX37 to EX42, wherein the at least one spreader roller translates and / or tilts under the forces induced by the continuous dough sheet.

[0093] EX44. The method according to any of EX37 to EX43, wherein elastic forces retain the axial ends of the at least one spreader roller and oppose the movements of said axial ends.

[0094] EX45. The method according to EX44, wherein the elastic forces are directed upwards.

[0095] EX46. The method according to any of EX37 to EX45, wherein the elastic forces are adjustable.

[0096] EX47. The method according to EX46, wherein the elastic forces are generated by springs, wherein a stiffness and a pre-load of the springs are adjustable.

[0097] EX48. The method according to any of EX37 to EX47, wherein an average height of the spreader roller is adjustable.

[0098] EX49. The method according to any of EX37 to EX48, wherein a concave bend facing upwards is formed by the continuous dough sheet upstream of the spreader roller and the method comprises: detecting a depth of the concave bend and adjusting the support elements as a function of said depth.

[0099] EX50. The method according to EX49 when according to EX46, EX47 or EX48, wherein adjusting the support elements comprises: adjusting the elastic forces and / or the average height of the spreader roller.

[0100] EX51 . The method according to EX50 when according to EX47, wherein adjusting the elastic forces and / or the average height of the spreader roller comprises: adjusting the pre-load of the springs; optionally the pre-load is adjusted as a function of a weight or grammage of the continuous dough sheet.

[0101] EX52. The method according to any of EX49 to EX51 , wherein detecting the depth of the concave bend and adjusting the support elements are performed continuously or at regular intervals, as a loop. EX53. The method according to any of EX37 to EX52, wherein flattening the continuous dough sheet is carried out in sequential steps by running the continuous dough sheet through a plurality of couples of flattening rollers arranged one after the other along the conveying direction.

[0102] EX54. The method according to EX53, comprising: supporting the portion of the continuous dough sheet on the upper part of the lateral surface of at least one spreader roller placed upstream of one or more of the couples of flattening rollers.

[0103] EX55. The method according to any of EX37 to EX54, wherein the recipe comprises as ingredients vegetable and / or alkaloid particles, a binder and an aerosol forming agent.

[0104] EX56. The method according to any of EX37 to EX55, wherein an amount of water in the mixture is from 25 percent to 35 percent on wet weight basis.

[0105] EX57. The method according to any of EX37 to EX56, wherein a thickness of the continuous dough sheet upstream of the at least one couple of flattening rollers, or of the plurality of couples of flattening rollers, is from 2 mm to 20 mm.

[0106] EX58. The method according to any of EX37 to EX57, wherein a final thickness of the continuous dough sheet downstream of the at least one couple of flattening rollers, or of the plurality of couples of flattening rollers, is from 0.15 mm to 0.35 mm.

[0107] EX59. The method according to any of EX37 to EX58, further comprising: drying the flattened sheet.

[0108] EX60. A process for manufacturing aerosol-generating article components, comprising: producing the sheet of aerosol-generating substrate for aerosol-generating articles through the method according to any of EX37 to EX59; gathering the sheet of aerosol-generating substrate and wrapping the gathered sheet of aerosol-generating substrate in a wrapper to form a continuous rod; cutting the continuous rod into a plurality of aerosol-generating article components each having a rod shape, each aerosol-generating article component comprising a gathered sheet formed from a cut portion of the sheet of aerosol-generating substrate.

[0109] EX61. An aerosol-generating article comprising at least one aerosol-generating article component made through the process according to EX60.

[0110] Examples will now be further described with reference to the figures in which:

[0111] Figure 1 shows schematically an apparatus for producing a sheet of aerosolgenerating substrate for aerosol-generating articles;

[0112] Figure 2 shows a different view of elements of the apparatus of figure 1 ;

[0113] Figure 2A shows an element of the apparatus of figure 1 ; Figure 2B shows a 3D view of the element of figure 2A;

[0114] Figure 2C shows another embodiment of the element of figure 2A;

[0115] Figure 3 is a different embodiment of the apparatus of figure 1 ;

[0116] Figure 4 shows an apparatus for manufacturing aerosol-generating article components;

[0117] Figures 5 and 6 show respectively a longitudinal section and a cross section of aerosol-generating article component manufactured through the apparatus of Figure 10;

[0118] Figure 7 is an exploded view of an aerosol-generating article comprising the aerosolgenerating article component of Figures 5 and 6;

[0119] Figure 8 is a flowchart of a method for producing a sheet of aerosol-generating substrate for aerosol-generating articles according to the invention.

[0120] Figure 4 shows an apparatus 100 for manufacturing aerosol-generating article components for aerosol-generating articles and may be part of a plant, not shown, for manufacturing aerosol-generating articles. The apparatus 100 is configured for actuating a process for manufacturing aerosol-generating article components. An overview of the components and general operation of apparatus 100 is provided below, demonstrating the use of a sheet of aerosol-generating substrate “S” for making aerosol-generating article components 114.

[0121] Subsequently, a detailed description of an apparatus 1 (shown in Figure 1) and a method for producing the sheet of aerosol-generating substrate “S” used by the apparatus 100 to create the aerosol-generating article component 114 will be provided.

[0122] Referring to Figure 4, the apparatus 100 for manufacturing aerosol-generating article components includes a reel holder 101 where the sheet of aerosol-generating substrate “S” is coiled in a reel 103. The sheet of aerosol-generating substrate “S” may be composed of vegetable and / or alkaloid particles (e.g. tobacco or tobacco free), a binder and an aerosol forming agent (e.g. glycerine).

[0123] An extraction device (not shown) is configured to uncoil the sheet of aerosolgenerating substrate “S” from the reel 103, and a conveyor guides the sheet “S” along a conveying direction “C” parallel to its longitudinal direction. For instance, the conveyor comprises a plurality of motorized rollers and / or one or more motorized belt conveyors located along the conveying direction "C".

[0124] Downstream of the reel holder 101 , in the conveying direction “C” the apparatus 100 includes a weakening device 104 comprising counterrotating rollers 102 and 105 for weakening the sheet of aerosol-generating substrate “S”. Each counterrotating crimping roller 102, 105 is operatively connected to a motor (not shown) for rotation to generate a plurality of substantially parallel ridges or corrugations on the sheet of aerosol -generating substrate “S”.

[0125] Further downstream, the apparatus 100 includes a gathering device 106, a wrapping device 111 , and a cutter 113. The gathering device 106 includes a converging tool shaped like a tapered funnel 110, which transitions the sheet of aerosol-generating substrate “S” from a flat configuration (upstream of the gathering device) to a gathered rod -shaped configuration (downstream of the gathering device) as it is conveyed and pulled through the tool. In another example (not shown), the sheet of aerosol-generating substrate “S” is pulled through devices and / or conveyors from downstream of the converging tool.

[0126] The wrapping device 111 is designed to wrap the rod-shaped sheet of aerosolgenerating substrate “S” in a wrapper 109 to form a continuous rod 112. The wrapping device 111 comprises a guide cooperating with a feeder of the wrapper 109. The guide, not shown in figure, may comprise a U-shaped channel with additional folding elements configured to close the wrapper 109 around the gathered sheet of aerosol-generating substrate “S”. The feeder of the wrapper 109 is represented as an auxiliary reel holder 107 on which the wrapper 109 is wound in an auxiliary reel 108.

[0127] The cutter 113, such as a rotating blade, is positioned downstream of the wrapping device 111 and is designed to cut the continuous rod 112 into multiple aerosol -generating article components 114.

[0128] The apparatus 100 may also include a controller (not shown in the figures) configured to synchronize the operations of the reel holder 101 , the weakening device 104, the auxiliary reel holder 107, the conveyor, and the cutter 113.

[0129] One aerosol-generating article component 114 comprising the gathered sheet of aerosol-generating substrate “S” in the wrapper 109 is shown in figures 5 and 6.

[0130] An aerosol-generating article 200 comprising one aerosol-generating article component 114 is shown in in the exploded view of figure 7. The aerosol-generating article 200 comprises (from left to right in figure 7): a front plug 203 (solid plug), the aerosolgenerating article component 114, a tubular plug 205 (hollow plug, for instance of cellulose acetate), a fine tubular plug 206 (like the tubular plug 205 but with a thinner wall) and a filter plug 207 (mouthpiece filter, usually made of tow). Each plug has a wrapping of its own helping to contain properly their content. A tipping paper 208 connects the filter plug 207 to the rest of the plugs, and the front plug 203, aerosol-generating article component 114, tubular plug 205 and fine tubular plug 206 are wrapped together into a wrapping paper 209. The tubular plug 205 and fine tubular plug 206 are cooling plugs configured to cool down the aerosol formed by heating the aerosol-generating article component 114. The apparatus 1 for producing the sheet of aerosol-generating substrate “S” is described with reference to figures 1 -3. As previously mentioned, the apparatus 1 is responsible for producing the sheet of aerosol-generating substrate “S”, which is subsequently reeled and used by apparatus 100 for making the aerosol-generating article component 114. Referring to figure 1 , the apparatus 1 comprises a dough mixer 2 configured for kneading a mixture with a recipe and water to form a dough “D”.

[0131] The dough mixer 2 may be per se known and may comprise or may be connected to an extruder having an outlet 3 for the dough “D”. A dough sheeter 4, embodied as calendering rollers 5, 6, is placed just downstream the outlet 3 and is configured to make a continuous dough sheet 7 from said dough “D”.

[0132] A belt conveyor 8 is placed downstream of the calendering rollers 5, 6. The belt conveyor 8 comprise a belt 9 coupled to a pair of motorised rollers 10, 11 according to a closed path. An upper branch of the closed path is configured to support and transport the continuous dough sheet 7 in a conveying direction “F” and towards a couple of flattening rollers.

[0133] The couple of flattening rollers comprises a lower flattening roller 12 and an upper flattening roller 13 rotating about respective main axes “X”, “Y”. The main axes “X”, “Y” are parallel one to the other and parallel to the ground. A lateral surface of the lower flattening roller 12 faces a lateral surface of the upper flattening roller 13. Positions and sizes of the lower flattening roller 12 and upper flattening roller 13 are such to delimit a gap between said lateral surfaces. The lower flattening roller 12 and upper flattening roller 13 are motorized to rotate in opposite directions. The gap is sized to flatten the continuous dough sheet 7 coming from the belt conveyor 8 and passing through said gap.

[0134] A further conveyor 14 placed downstream of the couple of flattening rollers supports and transport the flattened continuous dough sheet 7 through an oven 15 where the dough is dried. The sheet of aerosol-generating substrate “S” coming out of the oven 15 is wound in the bobbin 103.

[0135] A spreader roller 16 is positioned between the belt conveyor 8 and the gap of the couple of flattening rollers and is placed higher than the belt conveyor 8 and higher than the gap. In the illustrated embodiment of figure 1 , the spreader roller 16 is placed at an elevation about equal to that the elevation of the main axis “Y” of the upper flattening roller 13.

[0136] The spreader roller 16 is hanging from a support frame 17 situated above the upper flattening roller 13 and is linked to said support frame 17 through a couple of support elements 18. Each support element 18 has one extremity linked to the support frame 17 and an opposite extremity linked to one axial end of the spreader roller 16 (figures 1 , 2 and 2A). The spreader roller 16 is idle, i.e. , is free to rotate about an own main axis “Z”. For instance, the spreader roller 16 comprises a central shaft coaxial to the main axis “Z” and having the axial ends connected to the support elements 18. The spreader roller 16 further comprises an external tubular body mounted around the central shaft, for instance through bearings, and free to rotate with respect to the central shaft and about the main axis “Z”. The tubular body and therefore a lateral surface of the spreader roller 16 is made of stainless steel or aluminum alloy or Polyetheretherketone (PEEK). An external diameter of the tubular body may range from 10 mm to 30 mm.

[0137] In the example embodiment, each support element 18 comprises a tie rod provided with a coil spring 19. Therefore, the spring 19 exerts an elastic force directed upwards and substantially along a vertical direction. Furthermore, the tie rod is fixed to the frame 17 so that it can swing. This way, the support elements 18 allow movements of the axial ends of the spreader roller 16 independently of each other under forces applied to said spreader roller 16.

[0138] As shown by the arrows in figure 2A, each axial end may move up and down along a vertical direction, due to the elastic yielding of the spring 19, and also along horizonal directions, due to the swinging of the tie rod. The combination of these movements allows each axial end also to move along closed paths. Hence, the main axis “Z” of the spreader roller 16 is able to translate or tilt as shown in figures 2, 2A and 2B. Figure 2B shows in dashed lines possible circular paths of the axial ends of the spreader roller 16.

[0139] Figure 2C shows a variant embodiment of the support element 18, in which the spring 19 is enclosed in a cylinder 20 and works in compression. The spring 19 is interposed between a plunger 21 and a bottom wall of the cylinder 20. The cylinder 20 may also contain oil and the plunger 21 may be provided with through passages to work as an oil damper. According to a variant of figure 2C, the support element 18 comprises a device, not shown, for adjusting the pre-load of the spring 19. For instance, the device for adjusting the preload is configured to pre-compress and keep the spring 19 pre-compressed and to adjust said pre-load.

[0140] The pre-load on the springs 19 should be proportionate to the weight / grammage of the continuous dough sheet 7 in such a way as to lengthen the springs 19 only when local tensions are created on the continuous dough sheet 7 due to folds on one or the other side. For example, if the grammage the continuous dough sheet 7 is 200 g / m2, the pre-load on the springs 19 should be about 20 N / m, so that the springs 19 elongate by about 10 mm when the continuous dough sheet 7 creates a fold of 5 mm on either side of the spreading roller 18.

[0141] Furthermore, the stiffness of the spring 19 is adjustable or the spring 19 may be replaced with another spring 19 of different stiffness. Figure 1 schematically shows that each support element 18 is connected to an actuator 22, i.e. a motorized mechanism, configured to adjust an average vertical position, i.e. an average height, of the spreader roller 16. The average vertical position is the vertical position of the spreader roller 16 when the springs 19 are stressed only by the weight of the spreader roller 16. A sensor 23, e.g. a laser distance sensor or a camera, is mounted on the frame 17, upstream of the spreader roller 16 and faces downwards. The sensor 23 and the actuator 22 are operatively connected to a control unit 24, typically an electronic control unit, for instance a main control unit of the apparatus 1 .

[0142] The actuator 22 may be configured to move the whole support element 18 up and down.

[0143] Differently, in the support element 18 of figure 2C the actuator 22 may be connected to the device for adjusting the pre-load by compressing the spring 19. Indeed, the precompression of the spring 19 also adjusts the average vertical position of the spreader roller 16: in the embodiment of figure 2C, the greater the pre-compression, the lower is the height of the spreader roller 16.

[0144] The above disclosed apparatus 1 is configured to carry out a method for producing a sheet of aerosol generating substrate for aerosol-generating articles according to the invention.

[0145] According to the method (figures 1 and 8), the mixture with the recipe and the water is kneaded in the dough mixer 2 to form the dough “D”. For instance, the recipe comprises as ingredients vegetable and / or alkaloid particles (e.g. tobacco or tobacco free), a binder (e.g. carboxymethylcellulose) and an aerosol forming agent (e.g. gylcerin). An amount of water in the mixture is from 25 percent to 35 percent on wet weight basis.

[0146] The dough “D” is shaped into the continuous dough sheet 7 through the calendering rollers 5, 6 and advanced along a conveying path on the upper branch of the belt conveyor 8.

[0147] Downstream of the belt conveyor 8, the continuous dough sheet 7 is supported by the spreader roller 16 and rolls over an upper part of the lateral surface of said spreader roller 16. Since the spreader roller 16 is positioned higher than the upper branch of the belt conveyor 8, the continuous dough sheet 7 forms a concave bend facing upwards towards the sensor 23 and placed just upstream of the spreader roller 16.

[0148] The continuous dough sheet 7 coming downwards from the spreader roller 16 enters the gap between the lower flattening roller 12 and the upper flattening roller 13 and is flattened. For instance, a thickness of the continuous dough sheet 7 upstream of the lower flattening roller 12 and the upper flattening roller 13 is from 2 mm to 20 mm, a final thickness of the continuous dough sheet 7 downstream of the lower flattening roller 12 and the upper flattening roller 13 is from 0.15 mm to 0.35 mm.

[0149] The flattened continuous dough sheet 7 is carried by the further conveyor 14 through the oven 15 and dried. The sheet of aerosol-generating substrate “S” coming out of the oven 15 is wound in the bobbin 103.

[0150] While the continuous dough sheet 7 rolls on the spreader roller 16, the spreader roller 16, supported by the springs 19, translates and / or tilts under the forces induced by the continuous dough sheet 7. These forces are mainly due to the weight / grammage of the continuous dough sheet 7 and by the traction incurred by the continuous dough sheet 7. The elastic forces of the springs 19 are mainly directed upwards, retain the axial ends of the spreader roller 16 and oppose the movements of said axial ends.

[0151] This elastic motion of the spreader roller 16 caused by the forces induced by the continuous dough sheet 7 prevents accumulation of dough material at the gap and ensures a continuous and homogenous infeed of the continuous dough sheet 7 between the upper and lower flattening roller 12, 13.

[0152] In addition to the motion described above, the apparatus 1 of the embodiment of figure 1 is further configured to carry out a control procedure through the control unit 24, the sensor 23 and the actuator 22.

[0153] The sensor 23 is positioned and configured to detect a depth of the concave bend of the continuous dough sheet 7. The sensor 23 measures a distance from a surface of the continuous dough sheet 7 as it passes over a void between the belt conveyor 8 and the spreader roller 16.

[0154] The control unit 24 receives from the sensor 23 a signal correlated to the detected depth and controls the actuator 22 to adjust the support elements 18, continuously or at regular intervals, as a function of said signal.

[0155] Particularly, the control unit 24 controls the actuator 22 to adjust the average height of the spreader roller 16 according to a control loop. For instance, the average height of the spreading roller 18 is regulated according to a preset range of values that correspond to different depths of the concave bend created by the continuous dough sheet 7 between the belt conveyor 8 and the spreader rollers 18. For example, if the distance from the surface of the continuous dough sheet 7 is 10 cm, it means that the continuous dough sheet 7 has a large concave bend, while if the distance is 2 cm, it means that the continuous dough sheet 7 has a small concave bend. If the detected depth is too high with respect to a preset value, the spreader roller 16 is raised, if the detected depth is too small with respect to a preset value, the spreader roller 16 is lowered. The embodiment of the apparatus of figure 3 comprises three couples of flattening rollers, each comprising a lower flattening roller 12’, 12”, 12”’ and an upper flattening roller 13’, 13”, 13’”, arranged one after the other along the conveying direction “F”. Flattening is carried out in sequential steps by running the continuous dough sheet 7 through the plurality of couples of flattening rollers. A size of the gap of the couples of flattening rollers is gradually smaller from the first couple of rollers (on the left in figure 3) towards the last one (on the right), so that the continuous sheet of dough 7 is increasingly and gradually flattened and thinned. One spreader roller 16’, 16”, 16’” is placed upstream of each couple of flattening rollers. The structure and the way of operating of each couple of flattening rollers with the respective spreader roller 16, 16’, 16’” are the same as disclosed above referring to figure 1 .

Claims

CLAIMS1 . Apparatus for producing a sheet of aerosol-generating substrate for an aerosolgenerating article, the apparatus comprising: a dough mixer (2) configured for kneading a mixture with a recipe and water to form a dough (D); a dough sheeter (4) configured to make a continuous dough sheet (7) from said dough (D); at least one couple of flattening rollers placed downstream of the dough sheeter (4) with respect to a conveying direction (F) of the continuous dough sheet (7), the flattening rollers having lateral surfaces facing each other and delimiting a gap for the passage of the continuous dough sheet (7) to be flattened; at least one spreader roller (16) placed upstream of the at least one couple of flattening rollers, at a greater height than the gap and rotatable about a main axis (Z); the spreader roller (16) being configured to support a portion of the continuous dough sheet (7) on an upper part of a lateral surface of said spreader roller (16); support elements (18) each coupled to one of two opposite axial ends of the spreader roller (16); wherein the support elements (18) are configured to allow movements of the axial ends under forces induced by the continuous dough sheet (7).

2. Apparatus according to claim 1 , wherein each support element (18) comprises at least one spring (19) and the at least one spring (19) exerts an elastic force directed upwards.

3. Apparatus according to claim 2, wherein the at least one spring (19) is pre-loaded and a pre-load of the at least one spring (19) is adjustable.

4. Apparatus according to any of claims 1 to 3, wherein an average height of the spreader roller (18) is adjustable.

5. Apparatus according to any of claims 1 to 4, comprising: at least one actuator (22) connected to the support elements (18); a control unit (24) operatively connected to the actuator (22); a sensor (23) operatively connected to the control unit (24) and positioned and configured to detect a depth of a concave bend facing upwards and formed by the continuous dough sheet (7) upstream of the spreader roller (16);the control unit (24) being configured to carry out the following procedure: receiving from the sensor (23) a signal correlated to the depth of the concave bend; controlling the actuator (22) to adjust the support elements (18) as a function of said signal.

6. Apparatus according to claim 5 when claim 5 depends on claim 3, wherein adjusting the support elements (18) comprises: adjusting the pre-load of the springs (19).

7. Apparatus according to claim 6, wherein adjusting the pre-load of the springs (19) comprises: adjusting a length of the springs (19) and a height of the spreader roller (18).

8. Apparatus according to claim 5 when claim 5 depends on claim 4, wherein adjusting the support elements (18) comprises: adjusting the average height of spreader roller (18).

9. Apparatus according to any of claims 5 to 8, wherein the procedure is a control loop performed continuously or at regular intervals.

10. Apparatus according to any of claims 1 to 9, comprising a support frame (17) located above the spreader roller (18), wherein each axial end is linked to the support frame (17) through the respective support element (18) and is hanging from the support frame (17).11 . Apparatus according to any of claims 1 to 10, wherein the spreader roller ( 16) is free to rotate about the main axis (Z).

12. Apparatus according to any of claims 1 to 11 , wherein the lateral surface of the spreader roller (16) is made of stainless steel or aluminum or polymeric material.

13. Method for producing a sheet of aerosol-generating substrate for an aerosolgenerating article, the method comprising: kneading a mixture with a recipe and water to form a dough (D); making a continuous dough sheet (7) from said dough (D) and advancing the continuous dough sheet (7) along a conveying path; flattening the continuous dough sheet (7) by running the continuous dough sheet (7) through at least one couple of flattening rollers placed along the conveying path; wherein the method further comprises:supporting a portion of the continuous dough sheet (7) on an upper part of a lateral surface of at least one spreader roller (16) placed upstream of the couple of flattening rollers, wherein axial ends of the spreader roller (16) are movable under forces induced by the continuous dough sheet (7).

14. The method according to claim 13, wherein elastic forces retain the axial ends of the at least one spreader roller (16) and oppose the movements of said axial ends.

15. The method according to claim 13 to 14, wherein the axial ends are movable independently of each other along directions perpendicular to the main axis (Z).

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