EP4697991A1 - Apparatus and method for fluid application to a sheet material - Google Patents

Abstract

A method for fluid application to a sheet material, wherein the method comprises providing a sheet material (1), crimping (20) the sheet material and applying (21) fluid to the sheet material forming a series of fluid areas on the sheet material. The method further comprises forming (22) a rod from the sheet material provided with the series of fluid areas and cutting the rod in between two fluid areas of the series of fluid areas to form rod segments comprising at least a fluid area.

Description

APPARATUS AND METHOD FOR FLUID APPLICATION TO A SHEET MATERIAL

The present disclosure relates to a method and apparatus for fluid application to a sheet material.

In particular for consumables in the smoking industries, sheet material is treated with a flavour before said sheet material is used in the consumable. Typically, a flavour is applied to sheet material using a spraying process. However, spraying of liquid is often correlated with irregular flavour deposition. Irregular deposition of liquid on a sheet material is undesired as this may lead to inconsistent products and discoloration of outer materials of the consumable. Spraying of liquid also leads to contamination of the environment. This is unfavourable in view of surrounding machine parts and personnel, as well as in view of liquid waste.

There is need for a method and apparatus for fluid application to a sheet material limiting or eliminating above-mentioned disadvantages of prior art liquid application methods and apparatus. In particular, there is need for a method and apparatus for fluid application to a sheet material eliminating the undesired effects of sprayed liquid.

According to an aspect of the present invention, there is provided a method for fluid application to a sheet material. The method comprises providing a sheet material and applying fluid to the sheet material forming a series of fluid areas on the sheet material. The method further comprises forming a rod from the sheet material provided with the series of fluid areas and cutting the rod in between two fluid areas of the series of fluid areas to form rod segments comprising at least a fluid area. Thereby, for forming rod segments, the rod is cut transverse to a transport direction of the sheet material or transverse to the elongation of the rod, respectively.

The omission of spraying a liquid makes the method suitable for the application of fluids having different viscosity, otherwise possibly not suitable for being sprayed. In particular, the method is suitable for the application of fluids having higher viscosity than a liquid, such as, for example, gels or pastes. Gels and pastes are generally not suitable to be sprayed or at least not in desirable quantity and homogeneity. In addition, with the application of fluid on a sheet material in individual fluid areas, the location of fluid deposition is defined as well as the quantity of the fluid. Accordingly, reproducibility of a final product may be enhanced and environmental contamination with fluid - to other machine parts or personnel, - is basically omitted. Yet further, as no fluid is deposited elsewhere than on the sheet material, waste of fluid is reduced to a minimum.

The cutting of a rod in between fluid areas may also prevent the presence of fluid at a cutting location of the rod. Since a cutting location corresponds to the creation of an end of a rod segment, the absence of fluid at such an end of a rod segment means no fluid present that might possibly lead to discoloration of an end of the rod segment. Yet further, fluid tends to stick to a cutting knife. Accordingly, with the absence of fluid at a cutting location, cleaning intervals of a cutting device may be extended and maintenance of device parts may be reduced. Generally, maintenance requires downtime of an apparatus or of a production line, such that with the present invention not only product quality may be enhanced, also cost, time and material waste may be reduced.

Preferably, the method comprises cutting a rod in between two subsequent fluid areas, forming a rod segment comprising a single fluid area. By this, a series of fluid areas is deposited on the sheet material, while each single fluid area defines the amount of fluid per future rod segment cut from a rod formed from the sheet material.

Depending on a cutting position, a location of a fluid area in a rod segment may be defined. For example, a flavour or an aerosol-enhancing substance may be preferred at a more upstream or more downstream position of a rod segment when said rod segment is located in a final product. Such a final product may, for example, be an article comprising several segments arranged in an end-to-end arrangement, wherein at least one of the segments is a rod segment comprising at least one fluid area as described. For example, in an aerosol-generating article where a component is heated for aerosol production, it may be preferred that a flavour or another substance is close to a heat source. Or vice versa, it may be preferred that a flavour or other substance is kept at cooler regions of the article. Such a rod segment has a distinct orientation and may be oriented in a final product as needed or desired.

Preferably, the method comprises cutting the rod in a middle between two subsequent fluid areas, such that a rod segment comprises a fluid area arranged in a central portion of the rod segment, wherein opposite ends of the rod segment are formed by sheet material comprising blank areas. Blank areas are free from fluid as provided in a fluid area. The fluid area is arranged in a central portion of the rod segment with respect to a length of the rod segment. Preferably, the blank areas have a same length with respect to the length of the rod segment. Thus, preferably, symmetric rod segments are manufactured from the rod. This simplifies use of the rod segments as there is no distinct orientation of the rod segment. In addition, cutting in the middle of two fluid areas allows for generous tolerance in view of a registration of cutting position and fluid areas without risking to cut at the position of a fluid area. Cutting the rod in a middle between two subsequent fluid areas also enables the creation of rod segments of equal length.

Preferably, the method comprises cutting the rod and thereby forming rod segments of equal length.

Preferably, a series of fluid areas forms a periodic pattern with alternating fluid areas and blank areas along a longitudinal direction of the sheet material. The longitudinal direction of the sheet material preferably corresponds to a transport direction of the sheet material. Thereby, the rod formed from the sheet material comprising the periodic pattern of fluid areas accordingly comprises a periodic pattern of alternating fluid areas and blank areas along the length of the rod. The rod may be cut such that a rod segment comprises one or several periods of the periodic pattern of fluid areas. Preferably, the rod is cut such that the cut rod segment comprises exactly one period of the periodic pattern, while a period of the periodic pattern preferably comprises one fluid area and one blank area.

Preferably, a length of the rod segment is equal to a distance between blank areas measured from center-to-center of the blank areas when seen along the length of the rod segment. In such embodiments of the method, identical rod segments may be manufactured, wherein a length is directly correlated with the series of fluid areas applied to the sheet material.

For forming fluid areas, a fluid may be applied to distinct surface structures on a fluid application device. These surface structures may be protrusions or may be recesses.

Preferably, the method comprises applying fluid to recesses provided in a surface of a fluid application device and transferring the fluid of the recesses to the sheet material. Thereby, the series of fluid areas is formed on the sheet material.

Providing the fluid in recesses bears several advantages. The fluid to be applied is exactly located, namely to the position of the recess. A recess may limit diffusion of fluid to surrounding machine parts or sheet areas. In addition, the quantity of fluid to be applied is defined by the size of a recess.

While surface structures for a fluid may be provided in plates or rollers, rollers are preferred as these allow for a continuous fluid application to a sheet material. Fluid application by plates generally require interruption of the fluid application process, for example stopping a transport of a sheet material at the instant of fluid application.

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

Fluid applied to a sheet material with the method and apparatus according to the invention may basically be any fluid and any sheet material, where homogeneous fluid application is desired and a variety of fluids may be used.

The apparatus and method are particularly suitable for fluids and sheet materials used in the tobacco industries.

Preferably, the fluid is a liquid, a gel or a paste.

Preferably, the fluid comprises one or a combination of flavour, aerosol-former, aerosolenhancing substance, or nicotine.

The sheet material may in particular be a sheet material used in the manufacture of products of the tobacco industries. These products may be smoking or non-smoking articles, for example heat-not-burn articles or parts of such articles. For example, a sheet material after fluid application, is subsequently compressed, gathered or formed into a rod-shape. The sheet material may, for example, be a tobacco containing sheet such as for example tobacco cast leaf comprising homogenized tobacco material and an aerosol-former such as for example glycerine, wherein the cast leaf may be formed into a sensorial media plug. The sheet material may, for example, also be a tobacco-free cellulose-based aerosol-forming substrate comprising nicotine or flavours, while the nicotine or flavours may be provided in the sheet material before or with the fluid application process. The sheet material may, for example, also be a plastics foil, such as for example a polylactic acid foil that may be formed and used as a cooling plug. The sheet material may also be, for example, a tow material to be formed into a plug, for example into a hollow acetate tube or plug.

Preferably, the sheet material is a filter material, a tobacco containing material, a nontobacco containing cellulose-based material, a wrapping material or a foil.

Preferably, the sheet material is an acetate filter tow, a polylactic acid foil, a homogenized tobacco containing sheet, a hydroxypropylmethyl cellulose and carboxy methyl cellulose containing sheet, a wrapping paper or a tipping paper.

Sheet material made of or containing homogenized tobacco material is preferably cast leaf, for example as described in W0206/050470.

Tobacco-free cellulose-based aerosol-forming substrate may, in particular, be a hydroxypropylmethyl cellulose and carboxy methyl cellulose containing sheet, for example as described in WO2022/248378.

A sheet material used in the apparatus and method according to the invention is preferably provided as continuous sheet material, such as for example a band material. However, also individual pieces of sheet material may be processed or supplied to a fluid application apparatus.

The method may 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 the fluid of the surface of the fluid application device to the sheet material. Aligning may, for example, be realized by guides, for example guide rollers guiding the sheet material. Alternatively, or in addition, aligning may be realized by moving a fluid application device or parts thereof to the sheet material to be provided with the fluid.

The method may further comprise crimping the sheet material before applying fluid to the sheet material. Crimping is a preferred treatment of sheet material that may support the gathering or folding of the sheet material into a rod. Crimping may also have an effect on a resistance to draw, which may be relevant in articles of the tobacco industries.

The method may further comprise heating the fluid before applying the fluid to the sheet material. Heating may keep a fluid in a liquid state and reduce, for example crystallization. In particular, some flavours, such as for example menthol, have a tendency to crystallize. This effect may be reduced by heating the fluid or keeping the fluid flowing. In addition, by heating, the viscosity of some fluids may be varied to make them better suitable for fluid application.

According to another aspect of the present invention, there is provided an apparatus for fluid application to a sheet material. The apparatus comprises a conveyor for sheet-material and a fluid application device comprising a fluid application element for applying fluid to a sheet material transported by the conveyor past the fluid application device. The fluid application element comprises surface structures for applying a series of fluid areas to a sheet material according to said surface structures. The apparatus further comprises a rod forming device for forming a rod from the sheet material provided with the series of fluid areas, a rod cutting device arranged downstream of the rod forming device for cutting a rod into rod segments, and a control unit adapted to control the rod cutting device to cut the rod at a cutting position in between fluid areas.

Surface structures are preferably arranged at a predefined interval in order for a series of fluid areas to be arranged on the sheet material at such predefined intervals.

Preferably, the control unit is adapted to control a conveyor and a rod cutting device to cut a rod at cutting positions, which cutting positions are correlated with the surface structures of a fluid application element. Preferably, the control unit is adapted to control a conveyor and a rod cutting device such that cutting locations of the rod are arranged in between two neighbouring fluid areas. Most preferably, a cutting location is arranged in the middle between two neighbouring fluid areas, where the cutting location is void of applied fluid.

The fluid areas applied to a sheet material may basically have any desired shape. Accordingly, surface structures in a fluid application element defining the fluid areas may have any desired form. Preferably, a form of a fluid area and a form of a surface structure are simple geometrical shapes. Simple geometrical structures are easy to create in a surface of a fluid application device. Additionally, an amount of fluid to be applied to a sheet material and defined by the surface structure is easy to calculate and to be varied according to a desired need.

Preferably, surface structures are elongate and have a longitudinal axis.

Preferably, surface structures are in the form of rectangles. Rectangles are simple geometrical structures that allow for a same amount of fluid applied over a width, foe example an entire width, of a sheet material.

Sizes of surface structures define a quantity of fluid to be applied to a sheet material.

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

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

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

The extension perpendicular to the transport direction preferably corresponds to a length of a strip. The length of a strip may be smaller or equal to a width of a sheet material.

The above given forms and sizes of surface structures, in particular of recesses, have provided good results in fluid application from a fluid application device to a sheet material, good control of cutting rod segments and consistent results of the cut rod segments. In particular, good results are achieved in flavour application to sheet material used in the tobacco industries, in particular to homogenised tobacco containing sheets.

Distances between neighbouring surface structures may be adapted to a length of a rod segment to be cut from the rod manufactured from the sheet material provided with at least one fluid area. In some embodiment of the invention, the manufactured final rod segment comprises a single fluid area. Alternatively, the manufactured final rod segment may comprise a number of fluid areas.

A distance between neighbouring surface structures may, for example, be between 3 millimeter and 6 millimeter. Distances of neighbouring surface structures in this distance range have provided good results in providing individual and separate fluid areas to a sheet material, allowing rod-forming of the sheet material and cutting the rod reliably in between fluid-free regions between fluid areas. These distances have in particular provided advantageous for rod segments having a length between 8 millimeter and 20 millimeter, preferably having a length between 10 millimeter and 15 millimeter.

While surface structures in fluid application elements are adapted to provide fluid areas on a sheet material according to the surface structures, a distance between surface structures is provided such that no fluid is applied to the sheet material in between surface structures.

Preferably, a sheet material outside of fluid areas, in particular in between fluid areas, is fluid free and forms blank areas.

Preferably, surface structures are provided in the form of an array of strips arranged in parallel. Preferably, the strips of the array of strips are arranged perpendicular to a transport direction of the conveyor. Preferably, the strips of the array of strips are arranged at equal distances. Thus, the array of strips is capable to provide an array of strip-shaped fluid areas on the sheet material, wherein each strip forms an individual fluid area. Preferably, the array of strips is arranged around a circumference of a fluid application roller.

In preferred embodiments of the apparatus, surface structures are recesses in a surface of a fluid application element, for example, in a fluid application plate or in a fluid application roller. Preferably, some or all recesses have a same form and size.

Recesses may have a depth between 0.1 millimeter and 1 millimeter, for example 0.4 millimeter.

Preferably, a depth of a recess is constant. Preferably, a depth of some or of all recesses is constant.

Preferably, a depth of a recess varies. For example, a depth of some or of all recesses may vary.

Surface structures, in particular, recesses may have a surface roughness. While a size or rather volume of a recess may define a quantity of fluid to be deposited to a sheet material, a surface roughness may affect surface tension of a fluid and by this fluid retention in the recess. A surface roughness may be selected according to a viscosity of a fluid to be applied to a sheet material. It has been found that the lower a viscosity of a fluid, preferably, the higher a surface roughness in a recess.

Surface structures, in particular recesses may be formed by any suitable means. Preferably, recesses are formed by laser structuring or embossing. Embossing is a preferred method for the manufacturing of recesses in a surface, as embossing may provide a certain roughness in the recesses.

In the apparatus, the fluid application device preferably comprises a fluid reservoir in fluid connection with the fluid application element. From the fluid reservoir, fluid is preferably continuously provided to the fluid application element. A fluid reservoir may, for example, be in the form of a fluid bath and the fluid application element may be immersed or dipped into the fluid bath to provide the surface structures with fluid.

Preferably, the fluid application device comprises a fluid remover to remove excess fluid from a surface of a fluid application element. By this, excess fluid not provided on surface structures, for example in recesses, is removed from remaining parts of a surface of the fluid application element. A fluid remover may help to keep surface portions of a fluid application element in between surface structures clean from fluid. A fluid remover may also limit a filling of a recess, for example to prevent an overfilling of a recess. This supports a precisely located fluid application to a sheet material, a consistent and clearly defined amount of fluid to be applied and may reduce waste of fluid.

A fluid remover may, for example, be a scraper such as for example a doctor blade, arranged adjacent and in contact with the surface of a fluid application element. A scraper is particularly preferred in embodiments with surface structures in the form of recesses. In these embodiments, a scraper may be guided along and over a surface of a fluid application element to remove fluid from the surface except for the fluid in the recesses.

In preferred embodiments, a fluid application element is a fluid application roller. Fluid application rollers bear several advantages. For example, a fluid application roller may be the only moving element for fluid application. For example, with a fluid application roller, a continuous uptake of fluid and a continuous application of the absorbed fluid to a sheet material may be realized with simple means. A fluid removing may be performed continuously, for example by the provision of a stationary fluid remover in contact with a circumferential surface of the fluid application roller.

While surface structures may basically have any form and shape, simple shapes are preferred. Since surface structures shall provide individual fluid areas on a sheet material, preferably surface structures are elongate having a longitudinal axis, which longitudinal axis are arranged parallel to a rotation axis of the fluid application roller. By this, fluid provided on the surface structures may be applied to a sheet material by rolling a fluid application roller over the sheet material and transfer fluid according to the surface structures arranged in parallel to the sheet material forming fluid areas arranged in parallel. Preferably, a transport direction of a sheet material and a rotation direction of a fluid application roller are parallel. By this, surface structures arranged in parallel may be arranged perpendicular to the transport direct of the sheet material and thus preferably provide the sheet material with distinct fluid patterns distanced from each other in the transport direction. The rod formed from a laterally compressed sheet material may then easily be cut perpendicular to its longitudinal direction and in between fluid areas.

Preferably, surface structures are recesses in a circumferential surface of a fluid application roller.

The apparatus may further comprise aligning means to bring the sheet material and the surface of a fluid application device into contact with each other for the fluid application process. Aligning means may support a precise application of fluid to a sheet material.

The apparatus may comprise a temperature control unit adapted to control a temperature of a fluid.

The temperature control unit may comprise at least one of a heater or a cooler for heating or cooling fluid. By a heater or also a cooler, a fluid may be heated or cooled to an optimal temperature for fluid application. For example, a fluid may be heated or cooled to have an optimized viscosity for a fluid application process.

A temperature control unit may be adapted to control a temperature of fluid in the fluid application device. For example, a fluid temperature may be controlled in a fluid reservoir. Preferably, the temperature control unit is adapted to control a temperature of the fluid application element, preferably a roller.

The apparatus may further comprise a crimping device for crimping the sheet material. Crimped sheet material is widely used in the manufacture of products of the tobacco industries, in particular in segments of rod-shaped aerosol-generating articles. Preferably, the crimping device is arranged upstream of the fluid application device. By this, no subsequently applied fluid is transferred to the crimping device, which would otherwise lead to contamination of the crimping device and fluid waste.

The apparatus according to the invention and as described herein is preferably adapted and configured to perform the method according to the invention and as described herein.

For performing the method according to the invention and as described herein, preferably, an apparatus according to the invention and as described herein is used. Features and advantages as described relating to the method are applicable also to the apparatus and vice versa.

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.

Example Ex1 : A method for fluid application to a sheet material, the method comprising providing a sheet material; applying fluid to the sheet material forming a series of fluid areas on the sheet material; forming a rod from the sheet material provided with the series of fluid areas; cutting the rod in between two fluid areas of the series of fluid areas to form rod segments comprising at least a fluid area.

Example Ex2: The method according to example Ex1 , therein cutting the rod in between two subsequent fluid areas, forming a rod segment comprising a single fluid area.

Example Ex3: The method according to example Ex2, therein cutting the rod in a middle between two subsequent fluid areas, such that a rod segment comprises a fluid area arranged in a central portion of the rod segment, wherein opposite ends of the rod segment are formed by sheet material comprising blank areas.

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

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

Example Ex6: The method according to any one of example Ex3 to Ex5, wherein a length of the rod segments is equal to a distance between blank areas measured from center-to-center of the blank areas.

Example Ex7: The method according to any one of the preceding examples, therein applying fluid to recesses provided in a surface of a fluid application device and transferring the fluid of the recesses to the sheet material. Example Ex8: The method according to example Ex6, therein applying the fluid to the recesses provided in the surface of a fluid application roller comprised in the fluid application device.

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

Example Ex10: The method according any one of the preceding examples, wherein the fluid comprises one or a combination of flavour, nicotine, aerosol-former, or aerosol-enhancing substance.

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

Example Ex12: The method according to any one of the preceding examples, wherein the sheet material is a sheet material used in the manufacture of products of the tobacco industries.

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 wrapping material or a foil.

Example Ex14: The method according to example Ex13, wherein the sheet material is an acetate filter tow, a polylactic acid foil, a homogenized tobacco containing sheet, a hydroxypropylmethyl cellulose and carboxy methyl cellulose containing sheet, a wrapping paper or a tipping paper.

Example Ex15: The method according to any one of examples Ex7 to Ex14, further comprising 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 the fluid of the surface of the fluid application device to the sheet material.

Example Ex16: The method according to any one of the preceding examples, further comprising crimping the sheet material before applying fluid to the sheet material.

Example Ex17: The method according to any one of the preceding examples, further comprising heating the fluid before applying the fluid to the sheet material.

Example Ex18: An apparatus for fluid application to a sheet material, the apparatus comprising a conveyor for sheet-material; a fluid application device comprising a fluid application element for applying fluid to a sheet material transported by the conveyor past the fluid application device, wherein the fluid application element comprises surface structures for applying a series of fluid areas to a sheet material according to said surface structures; a rod forming device for forming a rod from the sheet material provided with the series of fluid areas; 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 in between fluid areas.

Example Ex19: The apparatus according to example Ex18, wherein the control unit is adapted to control the conveyor and the rod cutting device to cut a rod at cutting positions, which cutting positions are correlated with the surface structures of the fluid application element.

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

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

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

Example Ex23: The apparatus according to any one of examples Ex18 to Ex22, wherein a distance between neighbouring surface structures is between 3 millimeter and 6 millimeter.

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.

Example Ex25: The apparatus according to example Ex24, wherein the strips in the array of strips are arranged perpendicular to a transport direction of the conveyor.

Example Ex26: The apparatus according to any one of examples Ex18 to Ex25, wherein the surface structures are recesses in a surface of the fluid application element.

Example Ex27: The apparatus according to example Ex26, wherein all recesses have a same form and size.

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

Example Ex29: The apparatus according to any one of example Ex26 to Ex28, wherein a depth of a recess is constant.

Example Ex30: The apparatus according to any one of example Ex26 to Ex28, wherein a depth of a recess varies.

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

Example Ex32: The apparatus according to any one of example Ex18 to Ex31 , wherein the fluid application device comprises a fluid remover to remove excess fluid from a surface of the fluid application element. Example Ex33: The apparatus according to example Ex32, wherein the fluid remover is a scraper arranged adjacent and in contact with the surface of the fluid application element.

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

Example Ex35: The apparatus according to example Ex34, wherein the surface structures have a longitudinal axis, which longitudinal axis are arranged parallel to a rotation axis of the fluid application roller.

Example Ex36: The apparatus according to any one of examples Ex34 to Ex35, wherein the surface structures are recesses in a circumferential surface of the fluid application roller.

Example Ex37: The apparatus according to any one of examples Ex18 to Ex36, further comprising aligning means to bring the sheet material and the surface of the fluid application device into contact with each other.

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

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

Example Ex40: The apparatus according to any one of examples Ex38 to Ex39, wherein the temperature control unit is adapted to control a temperature of fluid in the fluid application device.

Example Ex41 : The apparatus according to example Ex40, wherein the temperature control unit is adapted to control a temperature of the fluid application roller.

Example Ex42: The apparatus according to any one of examples Ex18 to Ex41 , further comprising a crimping device for crimping the sheet material.

Example Ex43: The apparatus according to example Ex42, wherein the crimping device is arranged upstream of the fluid application device.

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

Figure 1 shows a rod forming process with fluid application;

Figure 2 shows a fluid application device;

Figure 3 shows a side view of a fluid application device;

Figure 4 is a schematic view of a fluid application roller;

Figure 5 shows a schematic illustration of a fluid application process;

Figure 6 shows a surface of a fluid application element;

Figure 7 shows a sheet material with fluid pattern and rod formed from the sheet material; and

Figure 8 shows segments cut from a rod. Fig. 1 illustrates a rod 10 manufacturing process from a substantially flat sheet material 1 , for example a sheet material 1 used in the tobacco industries, such as for example a tobacco containing cast leaf or a filter tow.

The continuous sheet material 1 is transported in a transport direction 100, for example by a conveyor or guide rollers (not shown). The sheet material 1 is in its flat shape guided between two crimping rollers 20 for crimping the sheet material 1. The crimped sheet material passes a fluid application chamber 21 , wherein the sheet material 1 of provided with a fluid, for example a flavour, such as for example menthol. The sheet material 1 provided with fluid is further transported to a rod forming device 22, for example a compression device or a gathering device such as for example, a garniture tongue. In the rod-forming device 22, the sheet material 1 is gathered perpendicular to its longitudinal or transport direction 100. The continuous rod 10 formed from the sheet material 1 that has been crimped and provided with a fluid may then be cut into individual segments.

While in known flavour application processes in the tobacco industries, chamber 21 typically comprises one or several flavour spraying nozzles, Fig. 2 shows an example of a fluid application device according to the invention.

The sheet material 1 is being by passing in between two crimping rollers 20 arranged parallel and next to each other. The crimped sheet material 1 is further transported in transport direction 100 to a fluid application device 3 arranged in a fluid application chamber 21 (indicated by dotted lines).

The fluid application device 3 comprises a fluid application roller 30 and a fluid reservoir 31 . The fluid application roller 30 is partially immersed into the fluid reservoir 31 to take up fluid provided in the fluid reservoir 31 . An alignment roller 32 is arranged outside the fluid reservoir 31 and parallel and next to the fluid application roller 30. The sheet material 1 is guided in between alignment roller 32 and fluid application roller 30, whereby fluid from the fluid application roller 30 is transferred to the sheet material 1. While the fluid preferably is a flavour, such as for example menthol, the fluid may also be any other fluid, such as for example an aerosol-former, an aerosolenhancing compound or nicotine.

The sheet material 1 so provided with fluid leaves the fluid application chamber 21 for being further processed. The fluid application device 3 is shown in a side view in more detail in Fig. 3.

The fluid applicator roller 30 is positioned and connected with the fluid reservoir 31 by a shaft. The alignment roller 32 brings the crimped sheet material 1 in contact with the fluid application roller 30. Alignment roller 32 and fluid application roller 30 rotate in opposite rotation direction as indicated by arrows 110. While the fluid application roller 30 rotates around its rotation axis, the fluid application roller 30 is immersed into fluid 4 in the fluid reservoir 31 with its lower side in Fig. 3. The application roller 30 carries fluid 4 on its surface 50, in particular in surface structures in the form of recesses provided in the circumferential surface 50 of the fluid application roller 30.

A scraper 33, for example a doctor blade, is provided at a position when the surface 50 of the fluid application roller 30 leaves the reservoir 31 . The scraper 33 is arranged at an angle to the surface 50 of the application roller 30 and clears the surface 50 of the application roller 30 from excess fluid 4. By this, a fluid pattern to be applied to the sheet material 1 may become more precise and homogeneous.

The crimped sheet material 1 contacts the surface 50 of the applicator roller 30 and the fluid is transferred from the surface 50 of the applicator roller 11 to the crimped sheet 1.

Depending on a fluid to be applied to the sheet material, the absorption characteristics of the sheet material 1 and possibly also on a diffusivity of fluid on the sheet material 1 , a contact of the sheet material 1 with the fluid application roller 30 may be set.

The rotation angle 34 of the applicator roller 30 defines a length of contact of the sheet material 1 with the surface 50 of the fluid application roller 30. During this contact fluid is transferred to the crimped sheet material 1. Such a contact starts at the position where the alignment roller 32 is in contact with 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.

In Fig. 4 a fluid application roller 30 comprising a circumferentially arranged pattern of alternating engraved recesses 54 in the surface 50 of the fluid applicator roller 30 and plain areas 55 in between the recesses 54 is shown. The recesses 54 have the shape of strips arranged in parallel. In examples for forming tobacco plugs having a length between 10 mm to 15 mm, the width 540 of a recess 54 may be between 6 mm and 10 mm. The recesses 54 may have a distance 550 between 3 mm and 6 mm corresponding to the width of a plain area in between the recesses 54. In the example shown in Fig. 4, the recesses 54 are arranged parallel to the rotation axis of the fluid application roller 30 and have a length shorter than the length of the fluid application roller 30. In other embodiments, the recesses 54 may extend from one end of the application roller 30 to the opposite end of the application roller 30.

Fig. 5 is a schematic view of a fluid application process. The surface 50 of the fluid application roller 30 comprises recesses 54 with plain areas 55 in between, for example as shown in Fig. 4. Fluid 4 from a fluid reservoir 31 is hosted 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 on its surface 50. With the scraper 33, the excess fluid 4 is removed from the surface 50 and let flow back to the reservoir 31 . Preferably, the scraper 33 removes fluid 4 from the surface 30 such that fluid 4 uptaken from the reservoir 31 is left in the recesses 54 in the surface 50 only.

Thus, the desired amount of fluid 4 to be applied to the sheet material 1 remains within the recesses 54 of the surface 50. This amount of fluid 4 is then transferred to the crimped sheet material 1 when the sheet material, for example a tobacco cast leaf, contacts the surface 50 of the fluid application roller 30.

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 areas 44 and blank areas 45, which blank areas 45 are fluid-free or at least free from the fluid 4 that is present in the fluid areas 44. For example, the sheet material 1 is provided with an alternating series of a flavoured area and a flavour-free area.

In Fig. 6, an example of a structured surface 50 of a fluid application element, for example a fluid application roller 30 is shown.

Recesses 54 in the form of rectangular strips are arranged in series and parallel to each other with plain areas 55 in between the recesses 54. Distance 58 from center to center of a plain area 55 will define a length of a future rod segment as shown in Figs. 7 and 8. Such a rod segment may, for example, be a tobacco plug having a length between 10 to 15 mm, for example 12 mm.

The recesses 54 are filled with a fluid from a fluid reservoir 31. The recesses 54 may, for example be embossed and comprise a certain roughness which retention of fluid in the recesses 54. The plain areas 55 are preferably cleaned from fluid, for example by a scraper moving over the surface 50 upon rotation of the roller 30. Purpose of having plain areas 55 is to avoid deposition of fluid in regions where a rod 10 formed from a sheet material treated with the fluid application roller 30 is cut into rod segments 101. By this, discoloration such as for example menthol stains, may be prevented at cut ends of rod segments 101.

The width 540 of a recess 54 is about 6 to10 mm, wherein the width 550 of a plain area 55 is about 3 to 6 mm.

A recess 54 has a preferred maximum depth of about 0,1 mm to 0,4 mm to 1 millimeter. By width 540, length and depth of recess 54, the amount of fluid 4 to be applied to a sheet material 1 is defined.

In Fig. 7 a crimped sheet 1 provided with a fluid pattern according to an application element of Fig. 6 is shown.

The sheet material 1 comprises a fluid pattern that corresponds to the pattern reproduced by the fluid application element, for example application roller 30, when the fluid has been transferred from the recesses 54 to the sheet material 1 .

The fluid areas 44 are arranged parallel to each other and spaced apart by a constant distance of a blank area 45.

By way of example, the width of the sheet material 1 is about 8 to 15 cm. A distance 48 from center to center of a blank area 45 defines the length of a future rod segment 101 , and is, for example, between 10 and 15mm such as 12mm. For the manufacture of rod segments 101 in this size range, a width 440 of a fluid area 44 is between 6 to 10 mm, while the fluid areas 44 are distance from each other by about 3 to6 mm, which corresponds to a width of a blank area 45. The crimped sheet material 1 is gathered transverse to the transport direction 100 and formed into a rod 10 as shown on the right side of Fig. 7. Thereby, a rod is formed comprising alternating fluid areas 44 and blank areas 45 along the rod length. Preferably, the rod is wrapped with a wrapper.

As shown in Fig. 8, the rod 10 is then cut at cutting positions 25 to form rod segments 101. The cutting positions 25 lie within a blank area 45, preferably in the middle of the blank area 45, and preferably cut the rod 10 into rod segments 101 of equal length 111. The length 111 of the rod segments 101 corresponds to the distance 48 between center to center of two consecutive blank areas 45 in the sheet material 1 and to the distance 58 between center to center of consecutive plain areas 55 on the surface of a fluid application element.

A rod segment 101 comprises a fluid area 44 arranged in a central region of the rod segment 101 when seen along the length 111 of the rod segment. Each end of the rod segment 101 is formed from blank areas 45 of the sheet material 1. Thus, cutting knifes of a cutting device are not contaminated with fluid when cutting the rod 10 and ends of the rod segment 101 are not discoloured by a fluid contained in the rod segment 101.

For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 10 % of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

1. A method for fluid application to a sheet material, the method comprising providing a sheet material; applying fluid to the sheet material forming a series of fluid areas on the sheet material; forming a rod from the sheet material provided with the series of fluid areas; cutting the rod in between two fluid areas of the series of fluid areas to form rod segments comprising at least a fluid area, the method further comprising: crimping the sheet material before applying fluid to the sheet material.

2. The method according to claim 1, therein cutting the rod in between two subsequent fluid areas, forming a rod segment comprising a single fluid area.

3. The method according to claim 2, therein cutting the rod in a middle between two subsequent fluid areas, such that a rod segment comprises a fluid area arranged in a central portion of the rod segment, wherein opposite ends of the rod segment are formed by sheet material comprising blank areas.

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

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

6. The method according to any one of the preceding claims, wherein the sheet material is an acetate filter tow, a polylactic acid foil, a homogenized tobacco containing sheet, a hydroxypropylmethyl cellulose and carboxy methyl cellulose containing sheet, a wrapping paper or a tipping paper.

7. An apparatus for fluid application to a sheet material, the apparatus comprising a conveyor for 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 transported by the conveyor past the fluid application device, wherein the fluid application element comprises surface structures for applying a series of fluid areas to a sheet material according to said surface structures, a rod forming device for forming a rod from the sheet material provided with the series of fluid areas; 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 in between fluid areas.

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 cutting positions, which cutting positions are correlated with the surface structures of the fluid application element.

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

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

11. The apparatus according to any one of claims 7 to 10, wherein the surface structures are recesses 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 structures have a longitudinal axis, which longitudinal axis are arranged parallel to a rotation axis of the fluid application roller.

14. The apparatus according to any one of claims 12 to 13, wherein the surface structures are recesses in a circumferential surface of the fluid application roller.