Method and apparatus for producing multiple sheets of alkaloid-containing material

Abstract

To provide a method for producing multiple sheets of material containing alkaloids.SOLUTION: The method includes a step (100) of providing a tank with slurry containing an alkaloid-containing material and water; a step (101) of providing the tank with multiple outlets; a step (102) of supplying the slurry from the outlets onto a movable support in order to form multiple parallel sheets of the alkaloid-containing material; and a step of keeping the parallel sheets of the alkaloid-containing material separated on the movable support while moving the movable support. The invention also relates to an apparatus (1) for producing multiple sheets of the alkaloid-containing material.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for producing multiple sheets of alkaloid-containing material, and in particular to a method and apparatus for producing multiple sheets of material for use in aerosol-generating articles such as cigarettes or "heat-and-burn" type alkaloid-containing products. [Background technology]

[0002] In addition to tobacco leaf, homogenized tobacco materials are also used today in the manufacture of tobacco products. These homogenized tobacco materials are typically produced from parts of the tobacco plant that are less suitable for the production of cut filler (e.g., tobacco stems or tobacco dust). Tobacco dust is typically produced as a by-product during the handling of tobacco leaf during manufacturing.

[0003] The most commonly used forms of homogenized tobacco material are reconstituted tobacco sheets and cast leaves. The process of forming homogenized tobacco material sheets generally involves mixing tobacco dust with a binder to form a slurry. The slurry is then used to create a tobacco web, for example, by casting the viscous slurry onto a moving metal belt to produce so-called cast leaves. Alternatively, a low-viscosity, high-moisture slurry can be used to create reconstituted tobacco in a process similar to papermaking. Once prepared, the homogenized tobacco web may be cut in a manner similar to uncut intact tobacco to produce tobacco cut filler suitable for cigarettes and other smoking articles. A process for making such homogenized tobacco is disclosed, for example, in European Patent No. EP0565360.

[0004] In the aforementioned process, the slurry is cast onto a substrate, such as a moving belt, and then heated to obtain a sheet of material that can be further processed to obtain a component of an aerosol-generating article. The moving belt with the cast sheet thereon travels inside a long "dryer" where the temperature is controlled to gradually heat and dry the sheet.

[0005] After drying of the relatively wide sheet, the sheet is divided into smaller sections and then wound into "small" bobbins. Alternatively, a large "master bobbin" is created and the entire sheet is wound onto the "large" bobbin and then stored. When the sheet needs to be further processed, the master bobbin is cut into smaller bobbins that are easier to handle.

[0006] Each time these process steps are performed, there is always a risk of damaging the sheet or smaller sections thereof due to the inherent fragility of the sheet and its "stickiness." Summary of the Invention [Problem to be solved by the invention]

[0007] There is a need for methods and apparatus that simplify the above-mentioned process, addressing the unique properties of the sheets of alkaloid-containing material in order to minimize damage to them during manufacture. [Means for solving the problem]

[0008] The present invention relates to a method for producing a plurality of sheets of alkaloid-containing material, the method comprising the steps of providing a slurry comprising an alkaloid-containing material and water into a tank, providing a plurality of outlets to the tank, dispensing the slurry from the outlets onto a movable support to form a plurality of parallel sheets of alkaloid-containing material, and maintaining the parallel sheets of alkaloid-containing material separated on the movable support while moving the movable support.

[0009] According to the present invention, multiple sheets are formed simultaneously from the slurry. The sheets are arranged parallel to one another on the same movable support. In this way, "smaller" sheets are already produced without lengthening the production, and since several sheets are produced in parallel, there is no need to join the sheets after their production. Furthermore, the smaller dimensions of the sheets may also allow for faster and more uniform drying.

[0010] As used herein, the term "sheet" refers to a layered element having a width and length substantially greater than its thickness. The combined width of parallel sheets is preferably greater than about 10 millimeters, more preferably greater than about 20 or 30 millimeters. Even more preferably, the width of the sheet of alkaloid-containing material is comprised between about 60 millimeters and about 2500 millimeters. The thickness of the sheet of alkaloid-containing material is preferably comprised between about 50 micrometers and about 300 micrometers, more preferably between about 100 micrometers and about 250 micrometers, and even more preferably between about 130 micrometers and 220 micrometers.

[0011] A continuous "sheet" is referred to herein as a "web."

[0012] The term "movable support" as used herein refers to any means comprising at least one longitudinally movable surface. The movable support may form a closed loop to provide uninterrupted transport in one direction. The movable support may include a conveyor belt. The movable support may be essentially flat or may exhibit a structured or unstructured surface. The movable support may have no openings in its surface or may include orifices, preferably sized so that the slurry deposited thereon cannot penetrate. The movable support may comprise a sheet-like, movable and flexible band. The band may be made of a metallic material, including, but not limited to, steel, copper, iron alloys, and copper alloys. The band may be made of rubber. The band may be made of a heat-resistant material so that it can be heated to accelerate the drying process of the slurry.

[0013] As used herein, the term "slurry" refers to a liquid-like, viscous, or pasty material that may include an emulsion of different liquid-like, viscous, or pasty materials and may contain a certain amount of solid-state particles (although the slurry still exhibits liquid-like, viscous, or pasty behavior).

[0014] An "alkaloid-containing material" is a material that contains one or more alkaloids. The alkaloids may include nicotine, which may be found, for example, in tobacco.

[0015] Alkaloids are a group of naturally occurring compounds that contain primarily basic nitrogen atoms. This group also includes some related compounds with neutral properties and even some related compounds with weakly acidic properties. Some synthetic compounds of similar structure are also called alkaloids. In addition to carbon, hydrogen, and nitrogen, alkaloids may also contain other elements such as oxygen, sulfur, and more rarely, chlorine, bromine, and phosphorus.

[0016] Alkaloids are produced by a wide variety of organisms, including bacteria, fungi, plants, and animals. They can be purified from crude extracts of these organisms by acid-base extraction. Caffeine, nicotine, theobromine, atropine, and tubocurarine are examples of alkaloids.

[0017] Preferably, the alkaloid-containing material comprises homogenized tobacco material. Thus, in this case, the alkaloid is nicotine. As used herein, the term "homogenized tobacco material" refers to a material formed by agglomerating particulate tobacco that contains the alkaloid nicotine.

[0018] The most commonly used forms of homogenized tobacco material are reconstituted tobacco sheets and cast leaves. The process of forming homogenized tobacco material sheets generally involves mixing tobacco dust with a binder to form a slurry. The slurry is then used to create a tobacco web. For example, so-called cast leaves are produced by casting a viscous slurry onto a moving metal belt. Alternatively, a slurry with a low viscosity and high moisture content can be used to create reconstituted tobacco in a process similar to papermaking.

[0019] Tobacco sheet materials, which can be referred to as reconstituted sheet materials, can be formed using particulate tobacco (e.g., reconstituted tobacco) or a blend of tobacco particulates, a humectant, and an aqueous solvent to form a tobacco composition. This tobacco composition can then be cast, extruded, rolled, or pressed to form a sheet material from the tobacco composition. Tobacco sheets can be formed using a wet process, in which tobacco fines are used to create a paper-like material, or a cast leaf process, in which tobacco fines are mixed with a binder material and cast onto a moving belt to form a sheet.

[0020] Homogenized tobacco sheets generally contain, in addition to tobacco, a binder. Additionally, homogenized tobacco sheets may contain aerosol formers such as guar and glycerin.

[0021] The term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds that may form an aerosol. Typically, the aerosol-forming substrate releases the volatile compounds upon heating. The aerosol-forming substrate may comprise an alkaloid-containing material that contains volatile alkaloid flavor compounds, which are released from the aerosol-forming substrate upon heating. The aerosol-forming substrate may comprise a homogenized material.

[0022] A slurry is formed to form a sheet of alkaloid-containing material.

[0023] The slurry may contain a number of different components or ingredients. These components may affect the properties of the cast sheet of alkaloid-containing material. The first component is the alkaloid-containing material, for example, in powder form. This material may be, for example, a tobacco powder blend, which preferably contains the majority of the tobacco present in the slurry. The tobacco powder blend is the source of the majority of the tobacco in the homogenized tobacco material and therefore provides flavor to the final product, such as the aerosol produced by heating the homogenized tobacco material.

[0024] The alkaloid-containing material powder preferably has a size of about 0.03 mm to about 0.12 mm. The size of the particles or powder of the alkaloid-containing material refers to the Dv95 size. Each of the values ​​listed above indicates the Dv95 particle size. The "v" in Dv95 indicates that the volume distribution is taken into account. The use of volume distribution introduces the concept of an equivalent sphere. An equivalent sphere is a sphere equivalent to the actual particle in the property being measured. Therefore, in light scattering, it is a sphere that will produce the same scattering intensity as the actual particle. This is essentially a sphere with the same volume of particles. Furthermore, the "95" in Dv95 refers to the diameter where 95% of the distribution has a smaller particle size and 5% has a larger particle size. Therefore, the particle size is the size according to the volume distribution where 95 percent of the particles have a diameter smaller than the stated value (the diameter of a corresponding sphere with substantially the same volume of the particle). A particle size of 60 micrometers means that 95 percent of the particles have a diameter smaller than 60 micrometers, the diameter being the diameter of a sphere having a corresponding volume smaller than the particle.

[0025] The Dv95 size of particles is measured using a Horiba LA950 or LA960 particle size distribution analyzer. The HORIBA LA-960 particle size analyzer measures size distribution using laser diffraction. This technique uses first principles to calculate size using light scattered from the particle (edge ​​diffraction) and light transmitted through the particle (secondary scattering refraction). The LA-960 incorporates Mie scattering theory.

[0026] A binder may be added to the slurry to enhance the tensile properties of the homogenized sheet. An aerosol former may be added to the slurry to facilitate the formation of an aerosol. Additionally, water may be added to the slurry to reach a certain viscosity and moisture content that is optimal for casting a web of alkaloid-containing material.

[0027] The amount of binder added to the slurry may comprise about 1 percent to about 5 percent by dry weight of the slurry. More preferably, the amount of binder comprises about 2 percent to about 4 percent. The binder used in the slurry may be any of the gums or pectins described herein. The binder may ensure that the powder of alkaloid-containing material, such as tobacco, remains substantially dispersed throughout the homogenized tobacco web. While any binder may be employed, preferred binders are natural pectins (such as fruit pectin, citrus pectin, or tobacco pectin), guar gum (such as hydroxyethyl guar, hydroxypropyl guar), locust bean gum (such as hydroxyethyl locust bean gum, hydroxypropyl locust bean gum), alginates, starches (such as modified or derivatized starches), celluloses (such as methylcellulose, ethylcellulose, ethylhydroxymethylcellulose, carboxymethylcellulose), tamarind gum, dextran, puralon, konjac flour, xanthan gum, and the like. A particularly preferred binder for use in the present invention is guar.

[0028] Suitable aerosol formers for inclusion in slurries for alkaloid-containing materials are well known in the art and include, but are not limited to, monohydric alcohols (such as menthol), polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.).

[0029] Examples of preferred aerosol formers are glycerin and propylene glycol.

[0030] The slurry may have an aerosol former content of greater than about 5 percent by dry weight. The slurry may have an aerosol former content of about 5 to about 30 percent by dry weight. More preferably, the aerosol former comprises about 10 to about 25 percent by dry weight of the slurry. More preferably, the aerosol former comprises about 15 to about 25 percent by dry weight of the slurry.

[0031] To increase the tensile strength of the alkaloid material web, cellulose pulp containing cellulose fibers is preferably added to the slurry, which acts as a reinforcing agent.

[0032] The introduction of cellulose fibers into the slurry typically increases the tensile strength of the sheet of alkaloid-containing material and acts as a reinforcing agent. Therefore, adding cellulose fibers may increase the resilience of the sheet of alkaloid-containing material. Cellulose fibers for inclusion in slurries for sheets of alkaloid-containing material are well known in the art and include, but are not limited to, softwood fibers, hardwood fibers, jute fibers, flax fibers, tobacco fibers, and combinations thereof. In addition to pulping, the cellulose fibers may be subjected to suitable processes such as refining, mechanical pulping, chemical pulping, bleaching, sulfate pulping, and combinations thereof. The cellulose fibers may include tobacco stem material, petioles, or other tobacco plant materials. Cellulose fibers, such as wood fibers, preferably have a low lignin content. Alternatively, fibers such as plant fibers may be used in conjunction with or in place of the above fibers, including hemp and bamboo. The length of the cellulose fibers is advantageously about 0.2 millimeters to about 4 millimeters. The average length by weight of the cellulose fibers is preferably about 1 millimeter to about 3 millimeters. Additionally, the amount of cellulose fiber preferably comprises from about 1 percent to about 7 percent, on a dry weight basis, of the total weight of the slurry (or homogenized tobacco sheet).

[0033] The average length of fibers refers to their actual length (whether they are curled or kinked) as measured by the MORFI COMPACT commercialized by Techpap SAS. The average length is the mathematical average of the fiber lengths measured by the MORFI COMPACT for measurements of N fibers (where N>5). The MORFI COMPACT is a fiber analyzer that measures fiber length according to the fiber structure, and therefore the actual generated length of the fiber. A measured object is considered a fiber if its length is comprised between 200 micrometers and 10,000 micrometers and its width is comprised between 5 micrometers and 75 micrometers. The fiber length is measured when deionized water is added to the fiber and the Morfi software is used.

[0034] The binder and cellulose fibers are preferably contained in a weight ratio comprised between about 1:7 and about 5:1, and more preferably in a weight ratio comprised between about 1:1 and about 3:1.

[0035] Preferably, the binder and aerosol former are present in a weight ratio of about 1:30 to about 1:1. More preferably, the binder and aerosol former are present in a weight ratio of about 1:20 to about 1:4.

[0036] The alkaloid-containing material is preferably tobacco. The binder and tobacco particles are preferably present in a weight ratio of about 1:100 to about 1:10. The binder and tobacco particles are more preferably present in a weight ratio of about 1:50 to about 1:15, and even more preferably about 1:30 to 1:20.

[0037] The aerosol formers and tobacco particles are preferably contained in a weight ratio of about 1:20 to about 1:1, and more preferably in a weight ratio of about 1:6 to about 1:2.

[0038] The aerosol-forming material and the cellulose fibers are preferably contained in a weight ratio of about 1:1 to about 30:1, and more preferably in a weight ratio of about 5:1 to about 15:1.

[0039] The cellulose fibers and tobacco particles are preferably contained in a weight ratio of about 1:100 to about 1:10, and more preferably in a weight ratio of about 1:50 to about 1:20.

[0040] The slurry formed from the alkaloid-containing material, water, and preferably the material containing some or all of the above-mentioned ingredients may be contained in, for example, a tank. The slurry may reach the tank from a different location. Thus, the tank need not be the location where the slurry is formed. For example, the slurry may be produced in a silo and transferred to the tank via appropriate piping.

[0041] The slurry inside the tank is preferably kept at about ambient temperature, ie, between about 15 degrees Celsius and about 30 degrees Celsius.

[0042] From the tank, the slurry is transferred to a movable support to form a plurality of sheets, preferably formed on the surface of the movable support, such as a conveyor belt, the direction along which the movable support moves defining a conveying direction.

[0043] The tank is preferably located above a movable support, and the surface of the movable support on which the sheet is formed preferably defines a substantially horizontal surface.

[0044] The slurry is continuously fed into the tank, while the slurry is preferably fed onto a movable support to form a plurality of continuous sheets of alkaloid-containing material. Therefore, the silo and tank are preferably fluidly connected to allow the slurry to flow from one to the other.

[0045] Preferably, the level of the slurry is checked inside the tank, for example by a suitable sensor. The slurry is preferably introduced into the tank by a pump. More preferably, there is a feedback control loop, whereby a signal from the sensor regarding the level of the slurry can modify the pump output.

[0046] In this way, a predefined amount of slurry is preferably maintained in the tank.

[0047] The tank is preferably box-shaped. Preferably, the tank includes walls. More preferably, the walls then include side walls. The side walls may include a first pair and a second pair of opposing walls, referred to as a first side wall, a second side wall, a third side wall, and a fourth side wall. Advantageously, the side walls are substantially vertical or inclined relative to a vertical plane. The first side wall and the second side wall, and the third side wall and the fourth side wall, face one another. The tank walls also preferably include a bottom wall.

[0048] The tank includes a plurality of outlets. The outlets are formed on a wall of the tank, for example, on the bottom wall. The outlets formed in the tank can be arranged in any configuration. Preferably, the outlets are distributed along a line. The outlets can be located at the end of a pipe extending from the tank. In this case, the tank can have one opening (for example, on the bottom wall), from which a main pipe extends. The main pipe then branches into multiple pipes, each terminating in an outlet. Alternatively, multiple openings can be formed in the tank (for example, on the bottom wall), from which multiple pipes extend, each starting from an opening and terminating in an outlet. Thus, in this case, the outlet can be located at the end of a pipe that supplies the slurry to the movable support.

[0049] The slurry is dispensed from the outlet onto a movable support.

[0050] The slurry may be applied directly onto the movable support, or one or more substrate sheets may be placed between the movable support and the tank so that the slurry is applied to the substrate sheets. The substrate sheets may be positioned on the movable support.

[0051] Preferably, the distance between the two nearest adjacent outlets remains constant among all outlets.

[0052] If the bottom wall of the tank is considered to define an (X,Y) plane (X being parallel to the conveying direction) and the side walls are considered (at least across the component) to extend along a Z axis parallel to the (X,Y) plane, then the outlets preferably form a line parallel to the Y axis, although the outlets may also be arranged in multiple parallel lines.

[0053] The moving support preferably moves along its longitudinal axis (conveying direction) to remove the slurry exiting the outlet. The dimension of the movable support perpendicular to the conveying direction is referred to as the width of the movable support. The support may comprise a movable belt, for example made of stainless steel. The support is preferably moved by a drum adapted to advance the movable support. The drum is further adapted to be in thermal contact with the movable support for the sheet of alkaloid-containing material.

[0054] The multiple outlets distribute the slurry at different locations onto the movable support or onto a substrate sheet placed on the movable support. Due to the fact that the movable support moves along the conveying direction, the distributed slurry forms different slurry sheets extending along the conveying direction, one for each different outlet. The dimension of the sheet formed on the movable support in a direction perpendicular to the conveying direction is called the sheet width.

[0055] Preferably, each of the sheets has a width of about 10 millimeters to about 300 millimeters. Preferably, all of the sheets simultaneously formed from the outlet have substantially the same width.

[0056] Preferably, the sheets formed from the outlets are non-overlapping, i.e., each sheet has one surface in contact with the movable support or substrate sheet. No sheet rests on top of another sheet. Preferably, there is no contact between different sheets formed from different outlets.

[0057] The sheets are maintained separated from one another during movement of the movable support, because otherwise the sheets would tend to bond together to form a single sheet due to the substantially liquid or pasty state of the slurry. Therefore, parallel sheets formed by the differently located outlets are maintained separated while the movable support transports the sheets along the transport direction.

[0058] In this way, multiple sheets are formed simultaneously, each having a relatively "small" width suitable for further processing steps, for example to form an aerosol-generating article, and steps such as dividing the sheet into multiple smaller sheets along the conveying direction are avoided.

[0059] Preferably, at least on a section of the movable support, a substrate sheet is provided, preferably a number of substrate sheets equal to the number of outlets, such that the slurry is deposited above the substrate sheet, whereby the slurry and substrate sheet together form a plurality of sheets of alkaloid-containing material.

[0060] The substrate sheet is preferably a fiber-containing substrate sheet, which may be used to form a sheet of alkaloid-containing material having a relatively high tensile strength, which may be used with a slurry having a low fiber content to strengthen the resulting sheet of alkaloid-containing material.

[0061] The substrate sheet containing the fibers is typically a relatively "strong" sheet, the tensile strength of which is such that it can be transported between rollers without the need for any additional substrate on which it must contact. The tensile strength of the substrate sheet is about 0.1 Newtons / (millimeter) 2 ~approximately 1 Newton / (mm) 2 It is preferable that the material consists of:

[0062] The substrate sheet may be made of different natural or synthetic materials, including cellulose, hemp, kenaf, bamboo pulp, cotton, silk, wood, or combinations thereof, with the choice of material being made according to the mechanical properties expected of the final sheet containing the alkaloid-containing material.

[0063] The fibers in the substrate sheet may be woven or non-woven. If non-woven, the fibers may be oriented primarily in one direction. Alternatively, the fibers may be oriented, for example, randomly. If woven, various patterns can be used. The substrate sheet may comprise a mat of fibers. The fibers may be randomly arranged, flattened into a sheet, or woven into a fabric. The substrate sheet may include a binder to hold the fibers together. The binder may include methylcellulose.

[0064] The base sheet is preferably a braided sheet. A braided sheet is a sheet in which fibers are entangled. It is not necessary for all fibers to be entangled, but some of them are. A braided sheet makes it possible to obtain a homogeneous and relatively high mechanical strength.

[0065] The fiber content in the base sheet is 50 grams / (meter) 2 It is preferable that it is lower than

[0066] The substrate sheet preferably comprises cellulose fibers. Cellulose fibers for forming the sheet are well known in the art and include, but are not limited to, softwood fibers, hardwood fibers, jute fibers, flax fibers, tobacco fibers, and combinations thereof. In addition to pulping, the cellulose fibers may be subjected to suitable processes such as refining, mechanical pulping, chemical pulping, bleaching, sulfate pulping, and combinations thereof. The cellulose fibers may include tobacco stem material, petioles, or other tobacco plant materials. Cellulose fibers, such as wood fibers, preferably have a low lignin content. Alternatively, fibers such as plant fibers may be used in addition to or as a substitute for the above fibers, including hemp and bamboo.

[0067] The fiber-containing base sheet contains fibers having an average fiber length of about 0.7 mm to about 50 mm. More preferably, the fiber of the fiber-containing base sheet contains fibers having an average fiber length of about 1 mm to about 25 mm. More preferably, the fiber of the fiber-containing base sheet contains fibers having an average fiber length of about 1 mm to about 10 mm. More preferably, the fiber of the fiber-containing base sheet contains fibers having an average fiber length of about 1 mm to about 5 mm. Even more preferably, the fiber of the fiber-containing base sheet contains fibers having an average fiber length of about 1.2 mm to about 1.8 mm.

[0068] The average length of fibers refers to their actual length (whether they are curled or kinked) as measured by the MORFI COMPACT commercialized by Techpap SAS. The average length is the mathematical average of the fiber lengths measured by the MORFI COMPACT for measurements of N fibers (where N>5). The MORFI COMPACT is a fiber analyzer that measures fiber length according to the fiber structure, and therefore the actual generated length of the fiber. A measured object is considered a fiber if its length is comprised between 200 micrometers and 10,000 micrometers and its width is comprised between 5 micrometers and 75 micrometers. The fiber length is measured when deionized water is added to the fiber and the Morfi software is used.

[0069] The substrate sheet defines a first surface and a second surface, one surface facing opposite the other. The first surface or the second surface may be a substantially planar surface. The first surface or the second surface may be horizontal, i.e., parallel to a horizontal plane, or may be inclined.

[0070] The second surface is preferably in contact with the movable support, while the slurry is preferably deposited on the first surface.

[0071] The slurry that contacts the base sheet may be completely absorbed or adsorbed by the base sheet, the slurry may form a layer, referred to as the second layer, on the first surface of the base sheet, or the slurry may be partially absorbed or adsorbed by the base sheet and may partially coat the first surface of the base sheet.

[0072] Preferably, the application of the slurry may form a second layer on the substrate sheet, essentially forming a coating layer of the slurry on the first surface of the substrate sheet.

[0073] The slurry may be applied by impregnating the substrate sheet with the slurry.

[0074] Depending on the composition of the base sheet, or the composition of the slurry, or the compositions of both the base sheet and the slurry, for example, the amount of water or the amount of binder contained in the slurry, the slurry may be minimally, partially, or mostly absorbed or adsorbed by the base sheet. If the slurry is only minimally or partially absorbed by the base sheet, a second layer will form on the surface of the base sheet where the slurry is applied, and a multi-layer sheet will be formed.

[0075] When an adsorption process is performed in which the slurry is absorbed or adsorbed by the substrate sheet, the substrate sheet becomes impregnated with the slurry. The slurry may be completely absorbed by the substrate sheet. The slurry may also form a coating layer and impregnate the substrate sheet.

[0076] Sorption is a physical and chemical process by which one substance binds to another. Specific examples of sorption are absorption (a substance in one state is incorporated into another substance in a different state, and such a liquid slurry is absorbed by a solid substrate sheet), or adsorption (ions and molecules are physically attached or bound onto the surface of another phase).

[0077] The resulting sheet formed by the substrate sheet and the slurry applied to the first surface may have different compositions in a cross section taken perpendicular to the first surface of the substrate sheet. The lowest concentration of the slurry may be present at the second surface. The highest concentration of the slurry may be present at the first surface. Between the first and second surfaces, the combination of substrate sheet material and slurry may be present in different concentrations.

[0078] The method preferably includes the step of simultaneously drying parallel sheets of alkaloid-containing material. After casting, the sheets are preferably dried to reduce their moisture content and then "cured." A drying station (or "dryer" for short) can be used to dry the sheets. Drying all the sheets together accelerates the process. Additionally, drying "smaller" sheets relative to wider sheets can result in more uniform drying of the sheets themselves, minimizing resulting defects.

[0079] In the drying station, the temperature of the sheet is preferably increased so as to reduce the moisture content within the sheet. The moisture content of the sheet at the casting step, i.e., the moisture content of the slurry, is preferably about 60 to about 80 percent. The moisture content of the sheet at the end of drying is preferably about 7 to about 15 percent of the total weight of the sheet of alkaloid-containing material. The moisture content of the sheet of alkaloid-containing material at the end of drying is preferably about 8 to about 12 percent of the total weight of the sheet of alkaloid-containing material. The moisture content of the slurry at the time of casting and at the end of the drying process is an important parameter to control, as it affects the homogeneity of the sheet and the manufacturability of the sheet of alkaloid-containing material in subsequent manufacturing steps.

[0080] The ideal moisture level for the slurry has been found to be about 60 to about 80 percent. Below this preferred range, the density of the slurry as cast is such that defects frequently appear in the formed sheet. Moisture levels outside this range can also result in a reduction in the tensile strength of the sheet, which can complicate efficient handling of the sheet of alkaloid-containing material in subsequent processing steps. Thus, the excess moisture that needs to be removed from the sheet during the drying process can be significant.

[0081] The removal of moisture is preferably carried out by exposure to a flow of heated fluid, which can be, for example, drying air, the drying air having a temperature higher than that of the cast sheet, although steam can also be used.

[0082] Preferably, the step of feeding the slurry from the outlet onto the movable support includes the step of spraying or discharging the slurry onto the movable support. To feed the slurry from the tank onto the movable support, the slurry can be sprayed or discharged onto the movable support, for example, by a suitable nozzle or gun. Thus, simple and effective sheet formation is achieved.

[0083] Preferably, the method includes adjusting the pressure or flow rate of the slurry supplied from each of the plurality of outlets separately. Preferably, the flow rate of at least one of the outlets is adjusted separately from the other flow rates. More preferably, the method includes varying the pressure of the slurry supplied from each of the plurality of outlets based on the flow rate of the slurry supplied from the same outlet. Preferably, the amount and pressure of the slurry exiting each outlet are monitored. This monitoring step may be part of a feedback loop, whereby the pressure at which the slurry is ejected or sprayed onto the movable support may vary depending on the amount of slurry per unit time forced onto the movable support. Thus, optimal distribution of the slurry onto the movable support is obtained. Additionally, the amount of slurry used to form each of the plurality of sheets is preferably the same.

[0084] The method preferably includes a step of stirring the slurry in the tank. The slurry generally arrives in the tank already in a mixed state. To obtain slurries with substantially identical properties at all outlets in the tank (which are located at different locations), stirring is also preferably performed inside the tank by a mixing device, for example, a screw conveyor. Additionally, constant stirring or mixing prevents any part of the slurry from drying out.

[0085] The method preferably includes heating the slurry at one or more of the outlets or within the tank. A "hot" slurry is a less viscous slurry and is therefore more easily distributed, particularly by spraying or discharging, onto a movable support. Preferably, the temperature of the slurry at the outlet is comprised between about 20 degrees Celsius and about 50 degrees Celsius.

[0086] The method preferably includes directing a stream of slurry delivered from one or more of the plurality of outlets relative to the movable support. Preferably, it is possible to adjust the direction in which the slurry from the tank reaches the movable support. Preferably, the shape of the slurry stream can also be changed. In this way, the slurry stream can be adjusted to obtain the desired sheet, achieving greater precision in sheet formation.

[0087] The present invention also relates to an apparatus for producing a plurality of sheets of alkaloid-containing material, the apparatus comprising a tank adapted to contain a slurry and having a plurality of outlets, a movable support adapted to move along a conveying direction, and a plurality of separators positioned parallel to the conveying direction and in contact with the surface of the movable support, the separators dividing the surface of the movable support into a number of sections, each of the plurality of outlets being located above a section.

[0088] The advantages of such an apparatus have already been described in relation to the present method and will not be repeated here. The slurry from the tank is transferred to the movable support via an outlet. In order to keep the slurry sheets separated from one another, the movable support on one of its surfaces (preferably the surface facing the tank) comprises a plurality of separators, whereby the slurry forming the various sheets is "confined" within the spaces defined by the separators, i.e., confined to limited portions of the surface of the movable support.

[0089] Each outlet passes through a section of the movable support formed by the separator, and preferably each of the multiple outlets passes through a different section, although two or more outlets may pass through the same section.

[0090] The apparatus preferably includes a spray or discharge gun at each of the plurality of outlets, for example, positioned at the end of a pipe extending from each outlet and used to spray or discharge the slurry onto that section of the movable belt.

[0091] The apparatus preferably includes a pressure regulator at each of the plurality of outlets. The apparatus preferably includes a flow meter at each of the plurality of outlets. There is preferably control of the parameters of the flow of the slurry from the tank to the movable support.

[0092] The width of the sections, perpendicular to the conveying direction, is preferably between about 10 millimeters and about 300 millimeters. Preferably, the width of each of the plurality of sheets is equal to or similar to the "standard" width of the small bobbins obtained by dividing the "master" sheet, so that the small sheets can immediately undergo further processing steps, for example to obtain aerosol-generating articles.

[0093] The height of the section in a direction perpendicular to the conveying direction is preferably about 10 millimeters to about 100 millimeters. The thickness of each of the plurality of sheets is preferably about 5 millimeters to about 20 millimeters. The thickness of all of the plurality of sheets is preferably substantially the same. The height of the section (here, height refers to the dimension substantially perpendicular to the surface of the movable support on which the slurry is deposited) is wide enough to contain the amount of slurry required to obtain such sheet thickness.

[0094] Preferably, the size or shape of each of the plurality of outlets is variable. The size and / or shape of the outlets can be varied to better control the flow of the slurry.

[0095] The present invention will now be better explained with reference to the accompanying drawings. [Brief explanation of the drawings]

[0096] [Figure 1] FIG. 1 is a schematic diagram of an apparatus for the production of multiple sheets of alkaloid-containing material according to the present invention. [Figure 2] FIG. 2 is a more detailed front view of the device of FIG. [Figure 3] FIG. 3 is a more detailed schematic side view of a portion of the apparatus of FIG. [Figure 4] FIG. 4 is a side view of a detail of the device of FIG. [Figure 5] FIG. 5 is a cross-sectional front view of the detail of FIG. [Figure 6] FIG. 6 is a flow chart of a method for producing multiple sheets of alkaloid-containing material in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0097] Referring initially to Figure 1, an apparatus for producing a plurality of sheets of alkaloid-containing material (all generally designated 10) in accordance with the present invention is presented and designated by the reference numeral 1. In this embodiment, the plurality of sheets 10 are sheets of homogenized tobacco material.

[0098] The apparatus 1 for producing multiple sheets of homogenized tobacco material comprises a sheet former 2 and, more preferably, also a drying apparatus 3 positioned downstream of the sheet former 2 in the direction of movement 11 (indicated by the arrow in FIG. 1 ) of the multiple sheets 10 of alkaloid-containing material.

[0099] Referring now to FIG. 2 , sheet-forming apparatus 2 comprises a tank 4 into which a slurry for forming a web of homogenized tobacco material is introduced, a pump 5 for introducing the slurry into the tank, a plurality of outlets, all indicated generally at 6, and a movable support 7 onto which the slurry is delivered from outlet 6. Tank 4 may have any geometric shape and, in the embodiment shown, is substantially prismatic. Slurry from a buffer tank or silo (not shown in the drawings) is transferred into the tank by pump 5. Pump 5 preferably includes a flow control (not visible in the drawings) that controls the amount of slurry introduced into tank 4. Pump 5 is advantageously designed to ensure that the transfer time of the slurry is kept to a necessary minimum. Furthermore, a sensor 40 is present in tank 4 to measure the level of the slurry. There is preferably feedback between sensor 40 and pump 5, so that an optimum level of slurry is substantially maintained in tank 4 at all times.

[0100] Tank 4 includes side walls 15 and further includes a bottom wall 16. A mixer 17 may be present inside the tank for agitating and / or mixing the slurry. The mixer may be, for example, a screw conveyor driven into operation by a motor 18.

[0101] The sheet forming apparatus 2 also comprises a movable support 7 onto which the slurry is fed to form a web 10 of homogenized tobacco material. The movable support 7 may comprise, for example, a continuous stainless steel belt 7 comprising a drum assembly. The drum assembly includes a main drum 8 (visible in Figures 3 to 5) located below the tank 4, which moves the movable support 7. The tank 4 is preferably mounted above the main drum 8. The conveying direction of the movable support 7 corresponds to the direction of movement 11.

[0102] The width of the tank 4 (by width is meant the direction perpendicular to the conveying direction 11 ) is preferably substantially the same as the width of the movable support 7 .

[0103] An opening 16a is formed in the bottom wall 16 of the tank and is connected to a main pipe 20. A main valve 21 regulates the flow of slurry through the main pipe 20. Downstream of the main valve 21 in the direction of slurry flow, the main pipe 20 branches into a number of branch pipes, all indicated with 22. The number of branch pipes 22 is equal to the number of outlets 6, and in fact each branch pipe 22 terminates at its free end in an outlet 6.

[0104] In a different embodiment (not shown), multiple openings are formed directly in the bottom wall 16 and multiple pipes are connected, each pipe to a different opening.

[0105] Each branch pipe is equipped with a valve 23, followed by a volumetric pump 24 (e.g., a lobe pump or gear pump), a pressure regulator 25, and a flow meter 26. Elements 23-26 are listed in the direction of slurry flow from the most upstream element (valve 23 located downstream of main valve 21) to the most downstream element (flow meter 26). Flow meter 26 and volumetric pump 24 are preferably part of a feedback system, whereby the value output by flow meter 26 regulates the volume of slurry delivered through pipe 22 by pump 24.

[0106] The series of elements is shown in Figure 3, where a side view of the sheet forming apparatus 2 is taken.

[0107] Each branch pipe 22 terminates in a gun 27 where there is an outlet 6. Each gun 27 includes a nozzle (not visible) representing the outlet, which may be, for example, a slit for injected slurry or a circle for sprayed slurry.

[0108] The gun 27 may be an ejector gun or a spray gun. In both systems (i.e., with an ejector gun or a spray gun), it may be possible to adjust the position and / or tilt of the gun. Additionally, compressed air may be used with an air pressure regulator to push the slurry out. In the case of an ejector gun, it is preferred that the outlet has an adjustable shape and size. In the case of an ejector gun, it is preferred that an adjustable spray shape (cone, spiral, etc.) is provided on the ejector gun.

[0109] The guns 27 preferably form a line, ie they are aligned along an axis, which line is preferably perpendicular to the conveying direction 11 .

[0110] Additionally, each branch pipe 22 may include an electric heating element and a temperature sensor (not shown in the drawings). Heating is used to prevent cooling of the slurry during transport.

[0111] As can be seen more clearly in Figures 4 and 5, the movable support 7 defines a surface 7a. The surface 7a is preferably planar. The movable support 7 includes a plurality of separators 30 positioned on the surface 7a of the movable support 7 that contacts the slurry. The separators 30 divide the surface 7a of the movable support into sections 31. The separators 30 preferably include walls, such as vertical walls, that are parallel to each other. The walls are parallel to the conveying direction 11 and are connected to the belt by threads so that they move / loop together with the belt. The width 32 of each section is preferably the width of a standard "small bobbin" used for further processing of the sheet 10 (e.g., preferably about 10 millimeters to about 300 millimeters). The widths 32 of all sections are preferably the same.

[0112] Preferably, a gun 27 is associated with each section 31. Each gun 27 has this section for covering with slurry.

[0113] Furthermore, additional sensors (not shown) are preferably arranged above the movable support 7 for measuring the weight per square centimeter of the homogenized tobacco layer on the movable support 7 and the thickness of this tobacco layer. The sensors may be, for example, nuclear measurement heads. Additional sensors (still not shown in the drawings) are preferably present as well, such as sensors for locating and determining defects in the cast web of homogenized tobacco, sensors for determining the moisture content of the slurry and parallel sheets 10, and temperature sensors for determining the temperature of the slurry in tank 4.

[0114] All sensors preferably transmit signals related to the respective parameters being measured (temperature, moisture slurry level, defects, etc.) to a central control unit 50 (see FIG. 1). The central control unit 50 is preferably electrically connected to one, some, or all of the pumps 5, 24, actuators, motor 18, sensors 40, gun 27, flow meter 26, or to additional circuits and actuators in apparatus 2 or the slurry preparation apparatus (not shown). If the sheet 10 reveals defects or inhomogeneities, or if the properties of the sheet 10 are outside of preset ranges, the central control unit 50 can direct changes in process parameters, thus affecting the properties of the slurry or the parameters of sheet formation. These process parameters may be, for example, the dimensions of the nozzle in gun 27, the flow rate of the slurry, the temperature of the slurry, the spray shape, or the amount of slurry in tank 4, or any combination thereof.

[0115] Drying apparatus 3 includes multiple individual drying zones, each preferably including steam heating below the support and heated air above the movable support 7, and preferably also adjustable exhaust control. Within drying apparatus 3, the homogenized tobacco web is dried on the support 7 to the desired final moisture content.

[0116] Referring now to FIG. 6, the function of apparatus 1, including sheet former 2, is as follows. Preferably, a slurry formed by mixing and combining tobacco powder, water, and other ingredients is transferred from a holding tank (not shown) to sheet former 2 within tank 4, in step 100, using, for example, an in-line mixer (also not shown). In step 101, main valve 21 is opened, and the slurry reaches branch pipe 22. Guns 27 are then operated in step 102 to feed the slurry onto movable support 7, such as a stainless steel belt 7. Each gun 27 deposits the slurry onto a different section 31 realized within movable support 7. Furthermore, any of steps 100-102 preferably includes monitoring the level of the slurry in tank 4, the moisture content of the slurry within tank 4, and the density of the slurry by appropriate sensors.

[0117] The thickness and basis weight of the sheet 10, controlled by a nuclear gauge immediately after the casting process, are continuously monitored and feedback controlled using a slurry measuring device. The formation of the sheet is carried out by guns 27 that spray or inject the slurry into different sectors 31 provided in the movable support 7. Due to the walls 30, the sheets remain separated during transport.

[0118] The sheet 10 then undergoes drying step 103 in drying apparatus 3. The sheets 10 preferably move continuously on a movable support so that they enter the dryer together, thus simultaneously drying them. The drying step preferably involves uniform and gentle drying of the sheet in an endless stainless steel belt dryer with individually controllable zones. During drying, a step (not shown) of monitoring the temperature of the sheet in each drying zone is preferably implemented to ensure a gentle drying profile in each zone. The web is dried to the desired final moisture on steel belt 7 using steam pan heating from the bottom and air drying above. All drying zones are equipped with steam flow and pressure controls, and air temperature and air flow are fully adjustable to provide the desired drying profile and ensure product residence time is respected.

[0119] At the end of the drying step 103, the sheet of homogenized tobacco material is preferably removed from the support 7, for example by means of a doctoring blade. Doctoring 104 of the sheet at the correct moisture content is preferably carried out after the drying station.

[0120] After drying step 103, sheet 10 is preferably wound onto several "small" bobbins in winding step 105. The bobbins may then be used for the manufacture of aerosol-generating articles (not shown).

Claims

1. 1. A method for producing a plurality of sheets of alkaloid-containing material, comprising: providing a slurry comprising an alkaloid-containing material and water in a tank; Providing a plurality of outlets in the tank; dispensing the slurry from said outlet onto a movable support to form a plurality of parallel sheets of alkaloid-containing material; moving the movable support while maintaining the plurality of parallel sheets of alkaloid-containing material separated on the movable support, and dispensing said slurry from said outlet onto a single continuous movable support to form a plurality of parallel sheets of alkaloid-containing material on said movable support.

2. o The method of claim 1, including the step of simultaneously drying said parallel sheets of alkaloid-containing material.

3. the step of dispensing the slurry from the outlet onto a movable support, o A method according to claim 1 or claim 2, comprising discharging the slurry onto the movable support.

4. A method according to any one of claims 1 to 3, comprising adjusting the flow rate of the slurry supplied separately from each of the plurality of outlets.

5. o The method of claim 4, comprising varying the pressure of the slurry delivered from each of the plurality of outlets based on the flow rate of the slurry delivered from the same outlet.

6. A method according to any one of claims 1 to 5, comprising the step of stirring the slurry in the tank.

7. A method according to any preceding claim, comprising heating the slurry at one or more of the plurality of outlets or inside the tank.

8. A method according to any preceding claim, comprising the step of directing a flow of slurry delivered from one or more of said plurality of outlets relative to said movable support.

9. 9. The method of any of claims 1 to 8, wherein the plurality of sheets of alkaloid-containing material are separated by a plurality of separators on the movable support while the movable support is moving.

10. the step of dispensing the slurry from the outlet onto a movable support, The method of any preceding claim, comprising spraying the slurry onto the movable support.

11. The method of any one of claims 1 to 10, comprising adjusting the pressure of the slurry supplied separately from each of the plurality of outlets.

12. The method according to any one of claims 1 to 11, wherein the slurry is applied onto a substrate sheet placed between the movable support and the tank.

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