Apparatus and method for applying fluid to sheet material

Abstract

A method for applying a fluid to a sheet material wherein the method comprises providing a sheet material (1), crimping (20) the sheet material, and applying (21) a fluid to the sheet material, thereby forming a series of fluid regions on the sheet material. The method further includes forming (22) a strip from the sheet material provided with the series of fluid regions, and cutting the strip between two fluid regions of the series of fluid regions to form a strip segment including at least the fluid regions.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a method and apparatus for applying a fluid to a sheet material. BACKGROUND

[0002] In particular, for consumables of the smoking industry, sheet materials are treated with a flavour before the sheet material is used in the consumable. Typically, the flavour is applied to the sheet material using a spraying process. However, spraying of liquids is generally associated with irregular flavour deposition. Irregular deposition of liquids on the sheet material is undesirable as this can lead to inconsistent products and discoloration of the outer material of the consumable. Spraying of liquids also leads to contamination of the environment. This is disadvantageous in terms of surrounding machine parts and personnel, as well as liquid waste.

[0003] There is a need for a method and apparatus for applying a fluid to a sheet material which limits or eliminates the above-mentioned disadvantages of the prior art liquid application methods and apparatus. In particular, there is a need for a method and apparatus for applying a fluid to a sheet material which eliminates the undesirable effects of spraying liquids. SUMMARY

[0004] According to an aspect of the present invention, there is provided a method for applying a fluid to a sheet material. The method comprises providing a sheet material and applying a fluid to the sheet material, thereby forming a series of fluid regions on the sheet material. The method further comprises forming a strip from the sheet material provided with the series of fluid regions, and cutting the strip between two fluid regions of the series of fluid regions to form a strip segment comprising at least a fluid region. Thus, in order to form the strip segment, the strip is cut transversely to the direction of transport of the sheet material or transversely to the elongation of the strip, respectively.

[0005] The omission of spraying liquids makes the method suitable for applying fluids having different viscosities which would otherwise not be suitable for spraying. In particular, the method is suitable for applying fluids having a higher viscosity than liquids, for example, such as gels or pastes. Gels and pastes are generally not suitable for spraying or at least not sprayed in the desired amount and uniformity. Additionally, with the application of the fluid on the sheet material in separate fluid regions, the location of the fluid deposition as well as the amount of fluid is defined. Thus, the repeatability of the end product can be enhanced and environmental contamination of the fluid to other machine parts or personnel is substantially omitted. Further, as there is no fluid deposited elsewhere than on the sheet material, waste of fluid is reduced to a minimum.

[0006] Cutting the strip between two consecutive fluid regions also prevents the presence of fluid at the cutting position of the strip. Since the cutting position corresponds to the creation of an end of the strip segment, the absence of fluid at this end of the strip segment means that there is no fluid that can cause discoloration of the end of the strip segment. Still further, fluid tends to stick to the cutting knife. Thus, with the absence of fluid at the cutting position, the cleaning interval of the cutting device can be extended and the maintenance of the device parts can be reduced. In general, maintenance requires a downtime of the equipment or production line, so that with the present invention, not only the product quality can be improved, but also the cost, time and material waste can be reduced.

[0007] Preferably, the method comprises cutting the strip between two consecutive fluid regions, thereby forming a strip segment comprising a single fluid region. Thereby, a series of fluid regions is deposited on the sheet material, while each single fluid region defines the amount of fluid of each future strip segment cut from the strip formed by the sheet material.

[0008] Depending on the cutting position, the position of the fluid region in the strip segment can be defined. For example, when the strip segment is located in a final product, a flavor or an aerosol enhancing substance can be preferred at a more upstream or more downstream position of the strip segment. This final product can for example be an article comprising several segments arranged in an end-to-end arrangement, wherein at least one of the segments is a strip segment comprising at least one fluid region as described. For example, in an aerosol generating article where a component is heated to generate an aerosol, it can be preferred that a flavor or another substance is in close proximity to the heat source. Or vice versa, it can be preferred that a flavor or other substance is kept at a cooler region of the article. Such strip segments have different orientations and can be oriented in the final product as needed or desired.

[0009] Preferably, the method comprises cutting the strip in the middle between two consecutive fluid regions, so that the strip segment comprises a fluid region arranged in a central portion of the strip segment, wherein the opposite ends of the strip segment are formed by the sheet material comprising blank regions. The blank regions do not contain fluid provided in the fluid region. The fluid region is arranged in the central portion of the strip segment with respect to the length of the strip segment. Preferably, the blank regions have the same length with respect to the length of the strip segment. Thus, preferably, symmetrical strip segments are manufactured from the strip. This simplifies the use of the strip segments, as the strip segments do not have different orientations. In addition, cutting in the middle between two fluid regions allows for large tolerances, without the risk of cutting at the position of the fluid regions, in view of the registration of the cutting position and the fluid region. Cutting the strip in the middle between two consecutive fluid regions also enables the creation of strip segments of equal length.

[0010] Preferably, the method comprises cutting the strip and thereby forming strip segments of equal length.

[0011] Preferably, the series of fluid regions forms a periodic pattern of alternating fluid regions and blank regions along the longitudinal direction of the sheet material. The longitudinal direction of the sheet material preferably corresponds to the direction of transport of the sheet material. Thus, a strip formed from the sheet material comprising the periodic pattern of fluid regions accordingly comprises a periodic pattern of alternating fluid regions and blank regions along the length of the strip. The strip can be cut such that the strip segments comprise one or several periods of the periodic pattern of fluid regions. Preferably, the strip is cut such that the cut strip segments comprise exactly one period of the periodic pattern, while the period of the periodic pattern preferably comprises one fluid region and one blank region.

[0012] Preferably, the length of the strip segment is equal to the distance between the centers of the blank regions measured from center to center when viewed along the length of the strip segment. In such embodiments of the method, identical strip segments can be manufactured, wherein the length is directly related to the series of fluid regions applied to the sheet material.

[0013] For forming the fluid regions, the fluid can be applied to different surface structures on the fluid application device. These surface structures can be protrusions or can be recesses.

[0014] Preferably, the method comprises applying the fluid to recesses provided in the surface of the fluid application device, and transferring the fluid of the recesses to the sheet material. Thus, a series of fluid regions is formed on the sheet material.

[0015] Providing the fluid in recesses has several advantages. The fluid to be applied is precisely positioned, i.e. precisely to the location of the recesses. The recesses can limit the spreading of the fluid to surrounding machine parts or sheet material regions. In addition, the amount of fluid to be applied is defined by the size of the recesses.

[0016] While the surface structures for the fluid can be provided in a plate or a roller, rollers are preferred as these allow for a continuous application of fluid to the sheet material. Fluid application by a plate typically requires interrupting the fluid application process, e.g. stopping the transport of the sheet material at the moment of fluid application.

[0017] Preferably, the sheet material is provided continuously, preferably in the form of a continuous sheet material. Thus, preferably, the method comprises applying the fluid to recesses provided in the surface of a fluid application roller comprised in the fluid application device, and continuously applying the fluid from the fluid application roller to the continuous sheet material.

[0018] The fluid applied to the sheet material with the method and the apparatus according to the present application can essentially be any fluid and any sheet material, wherein a uniform fluid application is desired and a variety of fluids can be used.

[0019] The apparatus and the method are particularly suitable for fluids and sheet materials used in the tobacco industry.

[0020] Preferably, the fluid is a liquid, a gel or a paste.

[0021] Preferably, the fluid comprises one or a combination of a flavour, an aerosol former, an aerosol enhancing substance or nicotine.

[0022] The sheet material can in particular be a sheet material for manufacturing a product of the tobacco industry. These products can be smoking articles or non-smoking articles, such as for example heat-not-burn articles or parts of such articles. For example, after the fluid application, the sheet material is subsequently compressed, gathered or formed into a rod. The sheet material can for example be a tobacco-containing sheet, such as for example a tobacco cast leaf comprising homogenized tobacco material and an aerosol former, such as for example glycerol, wherein the cast leaf can be formed into a sensory medium rod. The sheet material can also for example be a non-tobacco cellulose-based aerosol-forming substrate comprising nicotine or a flavour, while the nicotine or flavour can be provided in the sheet material prior to or in conjunction with the fluid application process. The sheet material can also for example be a plastic foil, such as for example a polylactic acid foil which can be formed and used as a cooling rod. The sheet material can also for example be a tow material to be formed into a rod, for example into a hollow acetate tube or rod.

[0023] Preferably, the sheet material is a filter material, a tobacco-containing material, a non-tobacco cellulose-based material, a packaging material or a foil.

[0024] Preferably, the sheet material is a cellulose acetate filter tow, a polylactic acid foil, a sheet comprising homogenized tobacco, a sheet comprising hydroxypropyl methylcellulose and carboxymethyl cellulose, a wrapping paper or a tipping paper.

[0025] The sheet material made of or containing homogenized tobacco material is preferably a cast leaf, for example as described in WO206 / 050470.

[0026] The non-tobacco cellulose-based aerosol-forming substrate can in particular be a sheet comprising hydroxypropyl methylcellulose and carboxymethyl cellulose, for example as described in WO2022 / 248378.

[0027] The sheet material used in the apparatus and method according to the present application is preferably provided as a continuous sheet material, such as for example a tape material. However, it is also possible to handle or feed a single sheet of sheet material to the fluid application apparatus.

[0028] The method can further comprise aligning the sheet material and the fluid application device to bring the surface of the fluid application device and the sheet material into contact with each other for transferring fluid from the surface of the fluid application device to the sheet material. The alignment can be achieved, for example, by guides, such as guide rollers that guide the sheet material. Alternatively or additionally, the alignment can be achieved by moving the fluid application device or parts thereof to the sheet material to be provided with fluid.

[0029] The method can further comprise crimping the sheet material prior to applying the fluid to the sheet material. Crimping is a preferred treatment of the sheet material that can support the sheet material to gather or fold into a rod. Crimping can also have an effect on the suction resistance that can be relevant for articles of the tobacco industry.

[0030] The method can further comprise heating the fluid prior to applying the fluid to the sheet material. Heating can keep the fluid in a liquid state and reduce, for example, crystallization. In particular, some flavors, such as menthol, have a tendency to crystallize. This effect can be reduced by heating the fluid or keeping the fluid flowing. Additionally, by heating, the viscosity of some fluids can be changed to make it more suitable for fluid application.

[0031] According to another aspect of the present invention, a device for applying a fluid to a sheet material is provided. The device comprises a conveyor for the sheet material and a fluid application device comprising a fluid application element for applying a fluid to the sheet material conveyed by the conveyor past the fluid application device. The fluid application element comprises a surface structure for applying a series of fluid regions to the sheet material in dependence on the surface structure. The device further comprises a rod forming device for forming a rod from the sheet material provided with the series of fluid regions, a rod cutting device arranged downstream of the rod forming device for cutting the rod into rod segments, and a control unit adapted to control the rod cutting device to cut the rod at a cutting position between the fluid regions.

[0032] The surface structure is preferably arranged at a predetermined interval so that the series of fluid regions is arranged on the sheet material at such predetermined interval.

[0033] Preferably, the control unit is adapted to control the conveyor and the rod cutting device to cut the rod at a cutting position that is related to the surface structure of the fluid application element. Preferably, the control unit is adapted to control the conveyor and the rod cutting device so that the cutting position of the rod is arranged between two adjacent fluid regions. Most preferably, the cutting position is arranged in the middle between two adjacent fluid regions, wherein the cutting position is free of applied fluid.

[0034] The fluid area applied to the sheet material can essentially have any desired shape. Thus, the surface structure in the fluid application element defining the fluid area can have any desired form. Preferably, the form of the fluid area and the form of the surface structure are simple geometric shapes. Simple geometric structures are easy to produce in the surface of the fluid application device. In addition, the amount of fluid to be applied to the sheet material and defined by the surface structure is easy to calculate and to vary as desired.

[0035] Preferably, the surface structure is elongated and has a longitudinal axis.

[0036] Preferably, the surface structure is in the form of a rectangle. A rectangle is a simple geometric structure which allows to apply the same amount of fluid over the width of the sheet material, e.g. the entire width.

[0037] The size of the surface structure defines the amount of fluid to be applied to the sheet material.

[0038] The surface structure may, for example, each have an extension in the transport direction or parallel to the transport direction of between 6 mm and 10 mm. The extension in the transport direction is preferably the extension in the transport direction of the conveyor or of the sheet material, respectively, and in particular corresponds to the direction of rotation of the fluid application roller. The extension in the transport direction preferably corresponds to the width of the strip or the width of the recess in the surface of the fluid application element.

[0039] The surface structure may, for example, each have an extension perpendicular to the transport direction of between 0.06 m and 0.3 m, preferably between 0.08 m and 0.2 m, for example between 0.1 m and 0.15 m. The extension perpendicular to the transport direction is the extension along or parallel to the surface of the fluid application element and perpendicular to the depth or height of the surface structure.

[0040] The extension perpendicular to the transport direction is preferably the extension perpendicular to the transport direction of the conveyor or of the sheet material, respectively, and in particular parallel to the axis of rotation of the fluid application roller.

[0041] The extension perpendicular to the transport direction preferably corresponds to the length of the strip. The length of the strip can be less than or equal to the width of the sheet material.

[0042] The surface structure, in particular the recess, of the above given form and size provides good results in the fluid application from the fluid application device to the sheet material, good control of the cut strip segments and consistent results of the cut strip segments. In particular, good results are achieved in the application of a flavour to a sheet material used in the tobacco industry, in particular to a sheet containing homogenized tobacco.

[0043] The distance between adjacent surface structures can be adapted to the length of the strip segments to be cut from the strip made of sheet material provided with at least one fluid region. In some embodiments of the invention, the final strip segments manufactured comprise a single fluid region. Alternatively, the final strip segments manufactured can comprise a plurality of fluid regions.

[0044] The distance between adjacent surface structures can for example be between 3 and 6 millimetres. The distance of adjacent surface structures in this distance range provides good results in providing individual and separate fluid regions to the sheet material, allowing reliable cutting of the strip in the fluid region free areas between the fluid regions. These distances are in particular provided to be advantageous for strip segments having a length between 8 and 20 millimetres, preferably a length between 10 and 15 millimetres.

[0045] The surface structures in the fluid application element are adapted to provide fluid regions on the sheet material while the distance between the surface structures is provided such that no fluid is applied to the sheet material between the surface structures.

[0046] Preferably, outside the fluid regions, in particular between the fluid regions, the sheet material is free of fluid and forms blank areas.

[0047] Preferably, the surface structures are provided in the form of an array of parallel arranged strips. Preferably, the strips of the array of strips are arranged perpendicular to the transport direction of the transport machine. Preferably, the strips of the array of strips are arranged with equal distance. Thus, the array of strips is able to provide an array of strip-shaped fluid regions on the sheet material, wherein each strip forms an individual fluid region. Preferably, the array of strips is arranged around the circumference of the fluid application roller.

[0048] In a preferred embodiment of the apparatus, the surface structures are recesses in the surface of the fluid application element, for example in a fluid application plate or in a fluid application roller.

[0049] Preferably, some or all of the recesses have the same form and size.

[0050] The recesses can have a depth between 0.1 and 1 millimetre, for example 0.4 millimetres.

[0051] Preferably, the depth of the recesses is constant. Preferably, the depth of some or all of the recesses is constant.

[0052] Preferably, the depth of the recesses varies. For example, the depth of some or all of the recesses can vary.

[0053] The surface structure, in particular the recesses, can have a surface roughness. While the size or volume of the recesses can define the amount of fluid to be deposited to the sheet material, the surface roughness can influence the surface tension of the fluid and thereby the retention of such fluid in the recesses. The surface roughness can be selected depending on the viscosity of the fluid to be applied to the sheet material. It has been found that the lower the viscosity of the fluid, preferably the higher the surface roughness in the recesses.

[0054] The surface structure, in particular the recesses, can be formed by any suitable means. Preferably, the recesses are formed by laser structuring or embossing. Embossing is a preferred method for manufacturing recesses in a surface, as embossing can provide a certain roughness in the recesses.

[0055] In the apparatus, the fluid application device preferably comprises a fluid reservoir fluidly connected to the fluid application element. Preferably, fluid is continuously provided from the fluid reservoir to the fluid application element. The fluid reservoir can for example be in the form of a liquid bath, and the fluid application element can be immersed or dipped into the liquid bath to provide fluid to the surface structure.

[0056] Preferably, the fluid application device comprises a fluid remover to remove excess fluid from the surface of the fluid application element. Thereby, excess fluid not provided on the surface structure, for example in the recesses, is removed from the remaining part of the surface of the fluid application element. The fluid remover can help to keep the part of the surface of the fluid application element between the surface structures free from fluid contamination. The fluid remover can also limit the filling of the recesses, for example to prevent overfilling of the recesses. This supports a precise application of fluid to the sheet material, an application of a consistent and well-defined amount of fluid, and can reduce waste of fluid.

[0057] The fluid remover can for example be a squeegee, for example such as a doctor blade, which is arranged adjacent to and in contact with the surface of the fluid application element. In embodiments with a surface structure in the form of recesses, a squeegee is particularly preferred. In these embodiments, the squeegee can be guided along and over the surface of the fluid application element to remove fluid from the surface except for the fluid in the recesses.

[0058] In preferred embodiments, the fluid application element is a fluid application roller. The fluid application roller has several advantages. For example, the fluid application roller can be the only moving element for fluid application. For example, with a fluid application roller, continuous uptake of fluid and continuous application of the taken-up fluid to the sheet material can be achieved with simple means. Fluid removal can be continuously performed, for example by providing a stationary fluid remover in contact with the circumferential surface of the fluid application roller.

[0059] Although the surface structure can essentially have any form and shape, a simple shape is preferred. Since the surface structure is to provide separate fluid regions on the sheet material, it is preferred that the surface structure is elongated, having a longitudinal axis which is arranged parallel to the rotation axis of the fluid application roller. Thereby, fluid provided on the surface structure can be applied to the sheet material by rolling the fluid application roller over the sheet material and transferring fluid according to the surface structure arranged in parallel to the sheet material, thereby forming fluid regions arranged in parallel. Preferably, the transport direction of the sheet material and the rotation direction of the fluid application roller are parallel. Thereby, the surface structure arranged in parallel can be arranged perpendicular to the transport direction of the sheet material and thus preferably provide different fluid patterns to the sheet material spaced apart from each other in the transport direction. The strip formed from the laterally compressed sheet material can then easily be cut perpendicular to its longitudinal direction and between the fluid regions.

[0060] Preferably, the surface structure is a recess in the circumferential surface of the fluid application roller.

[0061] The apparatus can further comprise an alignment device to bring the sheet material and the surface of the fluid application device into contact with each other for the fluid application process. The alignment device can support the fluid to be applied to the sheet material precisely.

[0062] The apparatus can comprise a temperature control unit adapted to control the temperature of the fluid.

[0063] The temperature control unit can comprise at least one of a heater or a cooler for heating or cooling the fluid. By means of the heater or also the cooler, the fluid can be heated or cooled to a temperature which is optimal for the fluid application. For example, the fluid can be heated or cooled to have an optimized viscosity for the fluid application process.

[0064] The temperature control unit can be adapted to control the temperature of the fluid in the fluid application device. For example, the fluid temperature can be controlled in the fluid reservoir. Preferably, the temperature control unit is adapted to control the temperature of the fluid application element, preferably the temperature of the roller.

[0065] The apparatus can further comprise a crimping device for crimping the sheet material. Crimped sheet material is widely used for manufacturing products of the tobacco industry, in particular for segments of rod-shaped aerosol generating articles.

[0066] Preferably, the crimping device is arranged upstream of the fluid application device. Thereby, no subsequently applied fluid is transferred to the crimping device, which would otherwise lead to contamination of the crimping device and fluid waste.

[0067] The apparatus according to the present invention and as described herein is preferably suitable for and configured to perform the method according to the present invention and as described herein.

[0068] For carrying out the method according to the application and as described herein, preferably, the device according to the application and as described herein is used. The features and advantages described in relation to the method also apply to the device and vice versa.

[0069] The application is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples can be combined with any one or more features of another example, embodiment or aspect described herein.

[0070] Example Ex1 : A method for applying a fluid to a sheet material, the method comprising

[0071] providing a sheet material;

[0072] applying a fluid to the sheet material, thereby forming a series of fluid regions on the sheet material;

[0073] forming a strip from the sheet material provided with the series of fluid regions;

[0074] cutting the strip between two fluid regions of the series of fluid regions to form a strip segment comprising at least a fluid region.

[0075] Example Ex2: The method according to example Ex1, wherein the strip is cut between two consecutive fluid regions, thereby forming a strip segment comprising a single fluid region.

[0076] Example Ex3: The method according to example Ex2, wherein the strip is cut midway between two consecutive fluid regions, such that a strip segment comprises a fluid region arranged in a central portion of the strip segment, wherein opposite ends of the strip segment are formed by sheet material comprising blank regions.

[0077] Example Ex4: The method according to any one of the preceding examples, wherein the series of fluid regions forms a periodic pattern of alternating fluid regions and blank regions along a longitudinal direction of the sheet material.

[0078] Example Ex5: The method according to any one of the preceding examples, wherein cutting the strip comprises forming strip segments of equal length.

[0079] Example Ex6: The method according to any one of examples Ex3 to Ex5, wherein the length of the strip segment is equal to a distance between blank regions measured from center to center of the blank regions.

[0080] Example Ex7: The method according to any one of the preceding examples, wherein the fluid is applied to a recess provided in a surface of a fluid application device, and the fluid of the recess is transferred to the sheet material.

[0081] Example Ex8: The method according to Example Ex6, wherein applying the fluid into the recess provided in the surface of the fluid application roller comprised in the fluid application device.

[0082] Example Ex9: The method according to any one of the preceding Examples, wherein the fluid is a liquid, a gel or a paste.

[0083] Example Ex10: The method according to any one of the preceding Examples, wherein the fluid comprises one or a combination of a flavour, nicotine, an aerosol former or an aerosol enhancing substance.

[0084] Example Ex11 : The method according to any one of the preceding Examples, wherein the sheet material is a continuous sheet material.

[0085] Example Ex12: The method according to any one of the preceding Examples, wherein the sheet material is a sheet material used for manufacturing a product of the tobacco industry.

[0086] Example Ex13: The method according to any one of the preceding Examples, wherein the sheet material is a filter material, a tobacco-containing material, a non-tobacco containing cellulose-based material, a packaging material or a foil.

[0087] Example Ex14: The method according to Example Ex13, wherein the sheet material is a cellulose acetate filter tow, a polylactic acid foil, a sheet containing homogenized tobacco, a sheet containing hydroxypropyl methylcellulose and carboxymethyl cellulose, a wrapping paper or a tipping paper.

[0088] Example Ex15: The method according to any one of Examples Ex7 to Ex14, further comprising aligning the sheet material and the fluid application device so that the surface of the fluid application device and the sheet material are in contact with each other for transferring the fluid of the surface of the fluid application device to the sheet material.

[0089] Example Ex16: The method according to any one of the preceding Examples, further comprising crimping the sheet material prior to applying the fluid to the sheet material.

[0090] Example Ex17: The method according to any one of the preceding Examples, further comprising heating the fluid prior to applying the fluid to the sheet material.

[0091] Example Ex18: An apparatus for applying a fluid to a sheet material, the apparatus comprising

[0092] a conveyor for the sheet material;

[0093] a fluid application device comprising a fluid application element for applying fluid to a sheet material conveyed by the conveyor past the fluid application device, wherein the fluid application element comprises surface structures for applying a series of fluid regions to a sheet material in dependence of the surface structures;

[0094] a strip forming device for forming a strip from the sheet material provided with the series of fluid regions;

[0095] a strip cutting device arranged downstream of the strip forming device for cutting the strip into strip segments;

[0096] a control unit adapted to control the strip cutting device to cut the strip at a cutting position between fluid regions.

[0097] Example Ex19: The apparatus according to example Ex18, wherein the control unit is adapted to control the conveyor and the strip cutting device to cut a strip at a cutting position, the cutting position being related to the surface structures of the fluid application element.

[0098] Example Ex20: The apparatus according to any one of examples Ex18 to Ex19, wherein the surface structures are in the form of rectangles.

[0099] Example Ex21 : The apparatus according to any one of examples Ex18 to Ex20, wherein the surface structures each have an extension in the conveying direction between 6 mm and 10 mm.

[0100] Example Ex22: The apparatus according to example Ex21, wherein the surface structures each have an extension perpendicular to the conveying direction between 0.06 m and 0.3 m, preferably between 0.08 m and 0.2 m, for example between 0.1 m and 0.15 m.

[0101] Example Ex23: The apparatus according to any one of examples Ex18 to Ex22, wherein the distance between adjacent surface structures is between 3 mm and 6 mm.

[0102] Example Ex24: The apparatus according to any one of examples Ex18 to Ex23, wherein the surface structures are provided in the form of an array of strips arranged in parallel.

[0103] Example Ex25: The apparatus according to example Ex24, wherein the strips in the array of strips are arranged perpendicular to the conveying direction of the conveyor.

[0104] Example Ex26: The apparatus according to any one of the examples Ex18 to Ex25, wherein the surface structure is a recess in the surface of the fluid application element.

[0105] Example Ex27: The apparatus according to example Ex26, wherein all recesses have the same form and size.

[0106] Example Ex28: The apparatus according to any one of the examples Ex26 to Ex27, wherein the recesses have a depth between 0.1 millimeter and 1 millimeter, for example 0.4 millimeter.

[0107] Example Ex29: The apparatus according to any one of the examples Ex26 to Ex28, wherein the depth of the recesses is constant.

[0108] Example Ex30: The apparatus according to any one of the examples Ex26 to Ex28, wherein the depth of the recesses varies.

[0109] Example Ex31 : The apparatus according to any one of the examples Ex18 to Ex30, wherein the fluid application device comprises a fluid reservoir in fluid connection with the fluid application element.

[0110] Example Ex32: The apparatus according to any one of the examples Ex18 to Ex31, wherein the fluid application device comprises a fluid remover to remove excess fluid from the surface of the fluid application element.

[0111] Example Ex33: The apparatus according to example Ex32, wherein the fluid remover is a squeegee arranged adjacent to and in contact with the surface of the fluid application element.

[0112] Example Ex34: The apparatus according to any one of the examples Ex18 to Ex33, wherein the fluid application element is a fluid application roller.

[0113] Example Ex35: The apparatus according to example Ex34, wherein the surface structure has a longitudinal axis arranged parallel to an axis of rotation of the fluid application roller.

[0114] Example Ex36: The apparatus according to any one of the examples Ex34 to Ex35, wherein the surface structure is a recess in a circumferential surface of the fluid application roller.

[0115] Example Ex37: The apparatus according to any one of the examples Ex18 to Ex36, further comprising an alignment device to bring the sheet material and the surface of the fluid application device in contact with each other.

[0116] Example Ex38: The apparatus according to any one of the examples Ex18 to Ex37, further comprising a temperature control unit adapted to control the temperature of the fluid.

[0117] Example Ex39: An apparatus according to Example Ex38, wherein the temperature control unit comprises at least one of a heater or a cooler for heating or cooling the fluid.

[0118] Example Ex40: An apparatus according to any one of Examples Ex38 to Ex39, wherein the temperature control unit is adapted to control the temperature of the fluid in the fluid application device.

[0119] Example Ex41 : An apparatus according to Example Ex40, wherein the temperature control unit is adapted to control the temperature of the fluid application roller.

[0120] Example Ex42: An apparatus according to any one of Examples Ex18 to Ex41, further comprising a crimping device for crimping the sheet material.

[0121] Example Ex43: An apparatus according to Example Ex42, wherein the crimping device is arranged upstream of the fluid application device. BRIEF DESCRIPTION OF DRAWINGS

[0122] Examples will now be further described with reference to the drawings in which:

[0123] Figure 1 A strip forming process with fluid application is shown;

[0124] Figure 2 A fluid application device is shown;

[0125] Figure 3 A side view of a fluid application device is shown;

[0126] Figure 4 A schematic view of a fluid application roller is shown;

[0127] Figure 5 A schematic view of a fluid application process is shown;

[0128] Figure 6 A surface of a fluid application element is shown;

[0129] Figure 7 A sheet material with a fluid pattern and a strip formed from the sheet material is shown; and

[0130] Figure 8 A segment cut from a strip is shown. DETAILED DESCRIPTION

[0131] Figure 1 A strip 10 manufacturing process is shown, in which a substantially flat sheet material 1 (e.g. a sheet material 1 for the tobacco industry, e.g. a cast leaf or a filter tow containing tobacco) is manufactured into a strip.

[0132] The continuous sheet material 1 is conveyed in a conveying direction 100, for example by a conveyor or guide rollers (not shown). The sheet material 1 is in its flat shape being guided between two curling rollers 20 for curling the sheet material 1. The curled sheet material passes through a fluid application chamber 21, in which the sheet material 1 is provided with a fluid, for example a flavour, for example such as menthol. The sheet material 1 provided with the fluid is further conveyed to a strand forming device 22, for example a compression device or an accumulation device, for example such as a garniture tongue. In the strand forming device 22, the sheet material 1 is accumulated perpendicular to its longitudinal direction or conveying direction 100. The continuous strand 10 formed by the sheet material 1 having been curled and provided with the fluid can then be cut into individual segments.

[0133] In known flavour application processes in the tobacco industry, the chamber 21 usually comprises one or several flavour spray nozzles, Figure 2 An example of a fluid application device according to the present application is shown.

[0134] The sheet material 1 is passing between two curling rollers 20 arranged parallel and close to each other. The curled sheet material 1 is further conveyed in the conveying direction 100 to a fluid application device 3 (indicated by dashed lines) arranged in the fluid application chamber 21.

[0135] The fluid application device 3 comprises a fluid application roller 30 and a fluid reservoir 31. The fluid application roller 30 is partially immersed in the fluid reservoir 31 to absorb the fluid provided in the fluid reservoir 31. An alignment roller 32 is arranged outside the fluid reservoir 31 and parallel to and close to the fluid application roller 30. The sheet material 1 is guided between the alignment roller 32 and the fluid application roller 30, whereby fluid from the fluid application roller 30 is transferred to the sheet material 1. Although the fluid is preferably a flavour, for example such as menthol, the fluid can also be any other fluid, for example such as an aerosol former, an aerosol enhancing compound or nicotine.

[0136] The sheet material 1 thus provided with fluid leaves the fluid application chamber 21 for further processing. The fluid application device 3 is shown in more detail in a side view in Figure 3 .

[0137] The fluid application roller 30 is positioned by a shaft and connected with the fluid reservoir 31. The alignment roller 32 brings the curled sheet material 1 in contact with the fluid application roller 30. The alignment roller 32 and the fluid application roller 30 are rotated in opposite rotational directions as indicated by arrows 110. In Figure 3In this process, when the fluid application roller 30 rotates about its axis of rotation, the fluid application roller 30 is immersed in the fluid 4 in the fluid reservoir 31 with its lower side submerged. The application roller 30 carries the fluid 4 on its surface 50 (especially in a surface structure in the form of a recess provided in the circumferential surface 50 of the fluid application roller 30).

[0138] When the surface 50 of the fluid application roller 30 leaves the reservoir 31, a scraper 33, such as a scraper blade, is positioned at a certain location. The scraper 33 is arranged at an angle to the surface 50 of the application roller 30 and removes excess fluid 4 from the surface 50 of the application roller 30. As a result, the fluid pattern to be applied to the sheet material 1 can become more precise and uniform.

[0139] The curled sheet material 1 contacts the surface 50 of the application roller 30, and fluid is transferred from the surface 50 of the application roller 11 to the curled sheet material 1.

[0140] Depending on the fluid to be applied to the sheet material, the absorption characteristics of the sheet material 1, and possibly also the diffusivity of the fluid on the sheet material 1, the contact between the sheet material 1 and the fluid application roller 30 can be set.

[0141] The rotation angle 34 of the application roller 30 defines the contact length between the sheet material 1 and the surface 50 of the fluid application roller 30. During this contact, fluid is transferred to the rolled-up sheet material 1. This contact begins at the position where the alignment roller 32 contacts the surface of the fluid application roller 30 and ends when the sheet material loses contact with the surface 50 of the application roller 30.

[0142] exist Figure 4 The image shows a fluid application roller 30, which includes a circumferentially arranged pattern of alternating etched recesses 54 in the surface 50 of the fluid application roller 30 and flat areas 55 between the recesses 54. The recesses 54 have the shape of parallel arranged strips. In an example used to form tobacco sticks with a length between 10 mm and 15 mm, the width 540 of the recesses 54 can be between 6 mm and 10 mm. The recesses 54 can have a distance 550 between 3 mm and 6 mm corresponding to the width of the flat areas between the recesses 54. Figure 4 In the example shown, the recess 54 is arranged parallel to the axis of rotation of the fluid application roller 30 and has a shorter length than the fluid application roller 30. In other embodiments, the recess 54 may extend from one end of the application roller 30 to the opposite end of the application roller 30.

[0143] Figure 5 This is a schematic diagram of the fluid application process. For example, as shown below. Figure 4As shown in Fig. 1, the surface 50 of the fluid application roller 30 comprises recesses 54 with flat areas 55 in between. Fluid 4 from the fluid reservoir 31 is contained in the recesses 54 of the surface 50 of the fluid application roller 30. When the fluid application roller 30 comes out of the fluid reservoir 31, excess fluid 4 will be located on its surface 50. With the doctor blade 33, the excess fluid 4 is removed from the surface 50 and is caused to flow back to the reservoir 31. Preferably, the doctor blade 33 removes the fluid 4 from the surface 30 such that the fluid 4 absorbed from the reservoir 31 is only left in the recesses 54 in the surface 50.

[0144] Thus, the required amount of fluid 4 to be applied to the sheet material 1 is kept within the recesses 54 of the surface 50. When the sheet material, e.g. tobacco cast leaf, contacts the surface 50 of the fluid application roller 30, this amount of fluid 4 is then transferred to the curled sheet material 1.

[0145] The fluid 4 is applied to the sheet material 1 according to the pattern formed by the recesses 54 on the roller surface 50. Thus, the sheet material 1 is provided with an alternating pattern of fluid regions 44 and blank regions 45, which are free of fluid or at least of the fluid 4 present in the fluid regions 44. For example, the sheet material 1 is provided with a series of alternating flavor regions and flavor-free regions.

[0146] In Figure 6 Fig. 3, an example of a structured surface 50 of a fluid application element, e.g. a fluid application roller 30, is shown.

[0147] The recesses 54 in the form of rectangular strips are arranged in series with each other and in parallel, with flat areas 55 in between the recesses 54. As shown in Fig. 3, the recesses 54 are arranged in a pattern of rows and columns. Figure 7 and 8 As shown in Figs. 2 and 3, the distance 58 from center to center of the flat areas 55 will define the length of future strip segments. Such strip segments can for example be tobacco rods of a length between 10 and 15 mm, e.g. 12 mm.

[0148] The recesses 54 are filled with fluid from the fluid reservoir 31. The recesses 54 can for example be embossed and comprise a roughness which will keep the fluid in the recesses 54. For example, upon rotation of the roller 30, the fluid is removed over the surface 50 by the doctor blade moving thereover, preferably clearing the flat areas 55. The purpose of having flat areas 55 is to avoid that fluid is deposited in the area where the strip 10 formed from the sheet material treated with the fluid application roller 30 is cut into strip segments 101. Thereby, discoloration, e.g. such as menthol stains, can be prevented at the cut ends of the strip segments 101.

[0149] The width 540 of the recesses 54 is about 6 to 10 mm, with the width 550 of the flat areas 55 being about 3 to 6 mm.

[0150] The recesses 54 have a preferred maximum depth of about 0.1 mm to 0.4 mm to 1 millimeter. By the width 540, length and depth of the recesses 54, the amount of fluid 4 to be applied to the sheet material 1 is defined.

[0151] In Figure 7 , it is shown that the coiled sheet material 1 is provided with a fluid pattern according to Figure 6 .

[0152] The sheet material 1 comprises a fluid pattern, which corresponds to the pattern reproduced by the fluid application element, e.g. the application roller 30, when the fluid has been transferred from the recesses 54 to the sheet material 1.

[0153] The fluid regions 44 are arranged parallel to each other and are separated by a constant distance of the blank regions 45.

[0154] By way of example, the width of the sheet material 1 is about 8 to 15 cm. The center-to-center distance 48 of the blank regions 45 defines the length of the future strip segment 101 and is, for example, between 10 and 15 mm, such as 12 mm. For the manufacture of strip segments 101 in this size range, the width 440 of the fluid regions 44 is between 6 to 10 mm, while the fluid regions 44 are at a distance of about 3 to 6 mm from each other, which corresponds to the width of the blank regions 45.

[0155] As shown on the right side of Figure 7 , the coiled sheet material 1 is gathered transversely to the transport direction 100 and formed into a strip 10. Thereby, a strip is formed, which comprises alternating fluid regions 44 and blank regions 45 along the strip length. Preferably, the strip is wrapped with a wrapper.

[0156] As shown in Figure 8 , the strip 10 is then cut at the cutting position 25 to form strip segments 101. The cutting position 25 is located within the blank regions 45, preferably in the middle of the blank regions 45, and preferably cuts the strip 10 into strip segments 101 of equal length 111. The length 111 of the strip segments 101 corresponds to the center-to-center distance 48 of two consecutive blank regions 45 in the sheet material 1 and to the center-to-center distance 58 of consecutive flat regions 55 on the surface of the fluid application element.

[0157] When viewed along the length 111 of the strip segment, the strip segment 101 comprises a fluid region 44 arranged in a central region of the strip segment 101. Each end of the strip segment 101 is formed by a blank region 45 of the sheet material 1. Thus, when cutting the strip 10, the cutting knives of the cutting device are not contaminated by fluid and the ends of the strip segments 101 are not discolored by the fluid contained in the strip segments 101.

[0158] For purposes of this specification and appended claims, unless 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, which can not be expressly disclosed. Thus, in this context, a number A is understood as A ± 10% of A. In this context, a number A can be considered to include values within the general standard error of a measurement of a property modified by the number A. In certain instances in the appended claims, the number A can deviate from the percentage recited above, provided that the amount by which A deviates does not materially affect the basic characteristics and novel features of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges, which can not be expressly disclosed.

Claims

1. A method for applying fluid to a sheet material, the method comprising providing a sheet material; applying fluid to the sheet material, thereby forming a series of fluid regions on the sheet material; forming a rod from the sheet material provided with the series of fluid regions; cutting the rod between two fluid regions of the series of fluid regions to form a rod segment comprising at least a fluid region, the method further comprising: crimping the sheet material prior to applying fluid to the sheet material.

2. The method according to claim 1, wherein the rod is cut between two consecutive fluid regions, thereby forming a rod segment comprising a single fluid region.

3. The method according to claim 2, wherein the rod is cut midway between two consecutive fluid regions, such that a rod segment comprises a fluid region arranged in a central portion of the rod segment, wherein opposite ends of the rod segment are formed by sheet material comprising blank regions.

4. The method according to any one of the preceding claims, wherein the series of fluid regions forms a periodic pattern of alternating fluid regions and blank regions along a longitudinal direction of the sheet material.

5. The method according to any one of the preceding claims, wherein the fluid comprises one or a combination of a flavour, nicotine, an aerosol former or an aerosol enhancing substance.

6. The method according to any one of the preceding claims, wherein the sheet material is a cellulose acetate filter tow, a polylactic acid foil, a sheet comprising homogenized tobacco, a sheet comprising hydroxypropyl methylcellulose and carboxymethylcellulose, a wrapping paper or a tipping paper.

7. An apparatus for applying fluid to a sheet material, the apparatus comprising a conveyor for a sheet material; a crimping device for crimping the sheet material; a fluid application device comprising a fluid application element for applying fluid to a sheet material conveyed by the conveyor past the fluid application device, wherein the fluid application element comprises a surface structure for applying a series of fluid regions to a sheet material in dependence of the surface structure, a rod forming device for forming a rod from the sheet material provided with the series of fluid regions; a rod cutting device arranged downstream of the rod forming device for cutting a rod into rod segments, a control unit adapted to control the rod cutting device to cut the rod at a cutting position between fluid regions.

8. The apparatus according to claim 7, wherein the control unit is adapted to control the conveyor and the rod cutting device to cut a rod at a cutting position, the cutting position being related to the surface structure of the fluid application element.

9. The apparatus according to any one of claims 7 to 8, wherein the surface structure is provided in the form of an array of strips arranged in parallel.

10. The apparatus according to claim 9, wherein the strips of the array of strips are arranged perpendicular to a conveying direction of the conveyor.

11. The apparatus according to any one of claims 7 to 10, wherein the surface structure is a recess in a surface of the fluid application element.

12. The apparatus according to any one of claims 7 to 11, wherein the fluid application element is a fluid application roller.

13. The apparatus according to claim 12, wherein the surface structure has a longitudinal axis arranged parallel to an axis of rotation of the fluid application roller.

14. The apparatus according to any one of claims 12 to 13, wherein the surface structure is a recess in a circumferential surface of the fluid application roller.

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