RU2796003C2 - Method and installation for casting a web of material containing alkaloids - Google Patents

Abstract

FIELD: casting plants.

SUBSTANCE: group of inventions relates to a casting plant for casting a web of material containing alkaloids and a method for casting a web of material. The casting plant for casting a web of material containing alkaloids comprises a casting box configured to contain pulp for casting to form a web of material containing alkaloids, the casting box forming one or more side walls, a sliding cover configured to slide along one or more than the side walls of the casting box, a movable support and a moulding blade configured to form the pulp located in the casting box on the movable support to obtain a cast web.

EFFECT: improved control of the pressure value inside the casting box and reduced presence of dry pulp inclusions, increased uniformity of the moulded sheet.

15 cl, 3 dwg

Description

The present invention relates to a foundry (for) and a method for producing a cast web of material containing alkaloids. In particular, the material containing alkaloids is a homogenized tobacco material, preferably used in an aerosol generating product, such as, for example, a cigarette or a tobacco-containing product such as "heating without burning".

Currently, in the production of tobacco products, in addition to tobacco leaves, homogenized tobacco material is also used. Such homogenized tobacco material is usually made from parts of a tobacco plant that are less suitable for the production of cut tobacco filler, such as tobacco stems or tobacco dust. Typically, tobacco dust is formed as a by-product during the processing of tobacco leaves during the manufacturing process.

The most widely used forms of homogenized tobacco material are reconstituted tobacco sheet and cast or molded sheet (tobacco cast leaf, abbreviated as TCL). The process for producing sheets from homogenized tobacco material typically includes the step of mixing tobacco dust and a binder to form tobacco pulp. The pulp is then used to create a tobacco web, for example by casting the viscous pulp onto a moving metal band to form a so-called shaped sheet. In an alternative embodiment, low viscosity, high water content pulp can be used to make reconstituted tobacco in a process similar to papermaking. Once produced, the homogenized tobacco webs can be cut in a manner similar to whole leaf tobacco to produce cut tobacco filler suitable for cigarettes and other smoking products. A process for the manufacture of such homogenized tobacco is disclosed, for example, in European patent EP0565360.

In an aerosol-generating article of the "heat without combustion" type, the aerosol-generating substrate is heated to a relatively low temperature so as to produce an aerosol but prevent combustion of the tobacco material. In addition, the tobacco present in the homogenized tobacco material is usually exclusively tobacco or contains mainly tobacco present in the homogenized tobacco material of such a "heating without combustion" type aerosol generating article. This means that the aerosol composition that is generated by such a "heated non-burning" aerosol generating article is essentially based solely on homogenized tobacco material. Therefore, it is important to ensure proper control of the composition of the homogenized tobacco material in order to control, for example, the taste of the aerosol.

Due to variations in the physical properties of the pulp, such as consistency, viscosity, fiber size, particle size, moisture content, or pulp soak time, unintended variations in the application of the pulp to the support during casting of the homogenized tobacco web may occur when using standard casting methods and foundry machines. . Suboptimal molding methods and equipment can cause inhomogeneity and defects in the cast web of homogenized tobacco.

The heterogeneity of the homogenized tobacco web can lead to difficulties in post-processing the homogenized tobacco web in the manufacture of an aerosol generating article. For example, inhomogeneity can lead to web cracking or even web rupture during fabrication or further processing of the web. This, in turn, can lead, for example, to equipment shutdowns. In addition, a heterogeneous tobacco web can lead to an undesirable difference in aerosol delivery between aerosol generating articles that are made from the same homogenized tobacco web.

With regard to the overall manufacturing process of a web of homogenized tobacco material, various parameters are important for the quality and stability of the final product. One of these parameters is the pulp pressure inside the casting box. Even small variations in pressure between batches of pulp can alter the uniformity of a web of homogenized tobacco material, which can then be rejected to the industry's stringent quality standards.

Document 2017/089589 A1 describes a homogenized tobacco sheet production line, comprising: a reservoir configured to contain a pulp formed from a mixture of tobacco powder, a binder and an aerosolizer in an aqueous medium; a molding device configured to receive pulp from the reservoir and mold the pulp into a homogenized tobacco material; a movable transport base on which said pulp is formed and which is configured to transport the homogenized tobacco material in the direction of transport; a slitting device downstream of the shaping device, configured to slit the homogenized tobacco material in a conveyance direction to form divided homogenized tobacco sheets; and a winding section downstream of the slitting device, configured to receive divided homogenized tobacco sheets from the slitting device and wind at least one of the divided homogenized tobacco sheets into a roll. It also relates to a process for the in-line production of a homogenized tobacco leaf.

WO 2016/096963 A1 describes a casting machine for producing a cast web of homogenized tobacco material, which comprises a casting box configured to contain a slurry of said homogenized tobacco material; moving base; a casting blade configured to cast said pulp in said casting box onto said movable base to form a cast web; wherein said casting machine additionally comprises first, second and third drives connected to said casting blade in first, second and third places, respectively, and suitable for changing the distance between said casting blade and said movable base in said first, second and third places , respectively.

There is a need for a casting machine and a method for producing a cast web from an alkaloid-containing material that can overcome or at least significantly reduce the above problem. In addition, it would be beneficial to have a casting plant and casting process in which good pressure control in the mold box can be achieved.

The present invention relates to a foundry for casting a web of alkaloid-containing material, comprising: a casting box capable of receiving pulp to be cast to form a web of alkaloid-containing material; moreover, the specified casting box forms one or more side walls; a sliding cover configured to slide along one or more side walls of the casting box; a movable support; and a forming blade configured to form the pulp contained in the casting box on the movable support to form a cast web.

The presence of a sliding cover on the mold box allows for improved control of the amount of pressure within the mold box and can reduce the presence of "dry pulp inclusions" that can form on the surface of the pulp in contact with air. Dry pulp inclusions are an inhomogeneity that may not dissolve into the pulp prior to casting, resulting in an inhomogeneity in the formed sheet.

As used herein, the term "sheet" means a flat element having a width and length substantially greater than its thickness. The width of the sheet is preferably greater than about 10 millimeters, more preferably greater than about 20 millimeters or approximately 30 millimeters. Even more preferably, the width of the sheet is from about 100 millimeters to about 300 millimeters. A continuous "sheet" is referred to in this document as a "canvas".

In this document, the term "forming blade" means an oblong-shaped element, which may have a substantially constant cross-section along the main parts of its longitudinal extent. It contains at least one edge, which is designed to come into contact with a pasty, viscous or liquid-like substance, which will be exposed to the specified edge, such as pulp. Said edge may have a sharp and knife-like shape. In an alternative embodiment, the edge of the blade may be rectangular or rounded.

As used herein, the term "movable bearing" refers to any device that contains a surface that can move in at least one longitudinal direction. The movable support may form a closed loop to enable continuous transportation in one direction. However, the movable support may also move in a reciprocating mode. The movable support may include a conveyor belt. The movable support may be substantially flat and may have a structured or unstructured surface. The movable support may not contain holes on its surface, or may contain only holes of such a size that they are impermeable to the pulp located on it. The movable support may comprise a sheet movable and flexible tape. The tape may be made of a metallic material, including but not limited to steel, copper, iron alloys, and copper alloys, or a rubber material. The belt may be made of a heat resistant material so that it can be heated to speed up the pulp drying process.

As used herein, the term "pulp" means a liquid-like, viscous or pasty material which may contain an emulsion of another similar liquid, viscous or pasty material, and which may contain some solid particles, provided that the state of the pulp remains liquid-like, viscous or pasty.

"Containing alkaloid material" is a material that contains one or more alkaloids. Alkaloids may include nicotine. Nicotine can be found, for example, in tobacco.

Alkaloids are a group of chemical compounds of natural origin, which mainly contain atoms that have the properties of bases. This group also includes some related compounds with neutral and even slightly acidic properties. Some synthetic compounds of similar structure are also referred to as alkaloids. In addition to carbon, hydrogen, and nitrogen, alkaloids can also contain oxygen, sulfur, and, less commonly, other elements such as chlorine, bromine, and phosphorus.

Alkaloids are produced by many organisms, including bacteria, fungi, plants, and animals. They can be isolated from crude extracts of these organisms by acid-base extraction. Examples of alkaloids are caffeine, nicotine, theobromine, atropine, tubocurarine.

In this document, the term "homogenized tobacco material" means a material obtained by agglomeration of tobacco particles, which contains the alkaloid nicotine. Thus, the material containing alkaloids may be a homogenized tobacco material.

The most widely used forms of homogenized tobacco material are reconstituted tobacco sheet and molded sheet. The process for making sheets of homogenized tobacco material typically includes mixing tobacco dust and a binder to form a pulp. This pulp is then used to produce a tobacco web. For example, by casting a viscous pulp onto a moving metal strip, a so-called shaped sheet is obtained. In an alternative embodiment, low viscosity, high water content pulp can be used to make reconstituted tobacco in a process similar to papermaking.

A sheet of homogenized tobacco material may be referred to as a reconstituted sheet and be formed using particulate tobacco (eg, reconstituted tobacco) or a particulate tobacco blend, a humectant, and an aqueous solvent to form a tobacco composition. The tobacco composition may then be molded, extruded, rolled, or pressed to form a sheet material from the tobacco composition. Tobacco sheet can be made using a wet process in which tobacco fine particles are used to form a paper-like material; or a sheet casting process in which tobacco fine particles are mixed with a binder and cast onto a moving belt to form a sheet.

The homogenized tobacco leaf typically contains, in addition to tobacco, a binder and an aerosolizing agent such as guar and glycerin.

As used herein, the term "aerosol-forming material" means a material that, when heated, is capable of releasing volatile compounds to generate an aerosol. Tobacco together with other compounds, in particular homogenized tobacco leaf containing an aerosol forming agent, can be classified as an aerosol forming material. The aerosol-forming substrate may comprise or consist of an aerosol-forming material. The homogenized tobacco leaf can be used as an aerosol forming material.

The pulp may contain several different components or ingredients. These components can affect the properties of the cast web of material containing alkaloids. The first ingredient is a material containing alkaloids, for example in the form of a powder. This material may be, for example, a tobacco powder mixture, which preferably contains the bulk of the tobacco present in the pulp. The tobacco powder mixture is the source of the bulk of the tobacco in the homogenized tobacco material and therefore imparts flavor to the final product, such as the aerosol resulting from heating the homogenized tobacco material. Cellulosic pulp containing cellulose fibers acting as a strengthening agent is preferably added to the pulp in order to increase the tensile strength of the web of alkaloid-containing material. A binder may be added. An aerosol generating agent may be added. Preferably, a binder and an aerosolizer are added to improve the tensile strength characteristics of the homogenized sheet and promote aerosol formation. In addition, water can be added to the pulp to achieve a certain viscosity and moisture that is optimal for casting a web of material containing alkaloids.

The amount of binder added to the pulp may range from about 1 percent to about 5 percent by dry weight of said pulp. More preferably, it ranges from about 2 percent to about 4 percent. The binder used in the pulp can be any of the gums or pectins described herein. The binder may ensure that the tobacco powder remains substantially distributed throughout the homogenized tobacco web. While any binder may be used, preferred binders are natural pectins such as fruit, citrus or tobacco pectins; guar gums such as hydroxyethyl guar and hydroxypropyl guar; locust bean gums such as hydroxyethyl and hydroxypropyl locust bean gums; alginate; starches such as modified or derivatized starches; celluloses such as methyl, ethyl, ethylhydroxymethyl and carboxymethylcellulose; tamarind gum; dextran; pullalone; konjac flour; xanthan gum; and the like. A particularly preferred binder for use in the present invention is guar.

In general, the incorporation of cellulose fibers into the pulp, acting as a reinforcing agent, increases the tensile strength of the web of tobacco material. Therefore, the addition of cellulosic fibers is able to increase the resilience of the web of homogenized tobacco material. Cellulosic fibers for incorporation into the pulp to form homogenized tobacco material are known in the art and include, without limitation, softwood fibers; hardwood fibers; jute fibers; linen fibers; tobacco fibers and combinations thereof. In addition to pulping, cellulosic fibers can be subjected to appropriate processing processes such as cleaning, mechanical pulping, chemical pulping, bleaching, sulphate pulping, and combinations of the above. Cellulosic fibers may contain materials from tobacco stems, veins, or other materials from the tobacco plant. Preferably, cellulosic fibers, such as wood fibers, have a low lignin content. Alternatively, plant fibers, including hemp and bamboo, can be used with or as an alternative to these fibers. The length of the cellulose fibers is preferably from about 0.2 millimeters to about 4 millimeters. Preferably, the average length per unit weight of the cellulose fibers is from about 1 millimeter to about 3 millimeters. Further, preferably, the amount of cellulose fibers is from about 1 percent to about 7 percent, based on dry weight, based on the total weight of the pulp (or homogenized tobacco leaf).

Suitable aerosol forming agents for incorporation into the pulp for homogenized tobacco material are known in the art and include, without limitation, monohydric alcohols such as menthol, polyhydric alcohols such as triethylene glycol, 1,3-butanediol, and glycerin; esters of polyhydric alcohols such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

Examples of preferred aerosol forming agents are glycerin and propylene glycol.

The aerosolizing agent content of the pulp may be greater than about 5 percent based on dry weight. The aerosolizing agent content of the pulp may be from about 5 percent to about 30 percent, based on dry weight. More preferably, the aerosolizing agent is present in an amount of from about 10 percent to about 25 percent, based on the dry weight of the pulp. More preferably, the aerosolizing agent is present in an amount of from about 15 percent to about 25 percent based on the dry weight of the pulp.

The binder and cellulose fibers are preferably included in a weight ratio of from about 1:7 to about 5:1. More preferably, the binder and cellulosic fibers are included in a weight ratio of from about 1:1 to about 3:1.

The binder and aerosolizer are preferably included in a weight ratio of from about 1:30 to about 1:1. More preferably, the binder and aerosolizer are included in a weight ratio of from about 1:20 to about 1:4.

Preferably, the alkaloid-containing material is tobacco. The binder and tobacco particles are preferably included in a weight ratio of from about 1:100 to about 1:10. More preferably, the binder and tobacco particles are included in a weight ratio of from about 1:50 to about 1:15, even more preferably from about 1:30 to 1:20.

The aerosolizing agent and tobacco particles are preferably included in a weight ratio of from about 1:20 to about 1:1. More preferably, the aerosolizer and tobacco particles are included in a weight ratio of from about 1:6 to about 1:2.

The aerosolizing agent and cellulose fibers are preferably included in a weight ratio of from about 1:1 to about 30:1. More preferably, the aerosolizer and cellulose fibers are included in a weight ratio of from about 5:1 to about 15:1.

The cellulose fibers and tobacco particles are preferably included in a weight ratio of from about 1:100 to about 1:10. More preferably, the cellulose fibers and tobacco particles are preferably included in a weight ratio of from about 1:50 to about 1:20.

The apparatus according to the present invention comprises a casting box for containing the pulp and a movable support, the casting or molding of the pulp being carried out by means of a molding blade.

The slurry may enter the casting box from another location. Therefore, the slurry may form elsewhere than in the casting box. For example, the slurry may be formed in a hopper or tank, from where it is conveyed to the casting box through a suitable tube. Preferably, the slurry is continuously fed into the casting box at the same time as the slurry is cast onto the movable support to form a continuous web of alkaloid-containing material. Thus, the hopper and the casting box are preferably in fluid communication, which allows the slurry to flow from one to the other.

The pulp is then loaded into a mold box, which is preferably maintained at a predetermined amount of pulp, eg, the pulp level in the mold box is set to a predetermined level. Preferably, the slurry is continuously fed into the casting box at the same time as the slurry is cast onto the movable support.

The casting box is preferably box-shaped. Preferably, the casting box has walls. More preferably, the walls in turn include side walls. The side walls may include first and second pairs of opposing walls. The first pair may include two side walls, referred to as first and second side walls, and the second pair may include third and fourth side walls. The side walls are preferably substantially vertical or inclined with respect to a vertical plane. The two side walls in each of the first and second pairs preferably face each other. Preferably, the walls of the mold box also include a bottom wall which has an opening. Preferably, the entire bottom wall forms an opening.

The walls of the mold box form the inner volume of the mold box, i.e., the walls define the inner volume of the mold box. As mentioned above, the casting box may include an opening in the lower region, for example on the bottom wall, such that the box is not a completely closed container. The hole is intended for pulp casting. Thus, the internal volume of the casting box is in contact with the external environment. Due to the presence of said hole, the volume of the "theoretical" box is considered as the internal volume of the casting box, in which the area bounded by the hole is closed. Accordingly, in the preferred embodiment, the line of demarcation between the internal volume of the box and the external environment is drawn as if this opening were closed by a wall. The opening may be formed in more than one wall (eg, corner openings, which are openings formed at the corners of the box). In addition, more than one hole may be present in the mold box. The interior volume is considered to be the volume within the box defined by the walls, where all openings are "substantially closed" by the geometric extension of the existing walls.

The mold blade is preferably positioned perpendicular to the casting direction. The web of material is formed by means of a forming vane, which applies the slurry contained in the casting box onto a movable support. The pulp, for example, from the casting box falls under the action of gravity and comes into contact with the mold blade. The edge of the casting blade forms a gap with the surface of the movable base, and the pulp passes through the hole formed by the said gap. The thickness of the cast web of material may be determined, inter alia, by the distance between the edge of the forming blade that comes into contact with the pulp and the surface of the movable support, ie the size of the gap defined above.

The forming blade is partially located outside the casting box and faces the movable support.

In addition, the casting box contains a sliding cover. The lid is connected to the casting box and is movable by sliding along one or more side walls of the casting box. Preferably, the movement of the lid during the sliding process is a substantially vertical movement. Preferably, the movement of the lid during sliding is a substantially linear movement. More preferably, the sliding lid comprises an outer surface which is the surface facing outward when the lid is mounted on the mold box, an inner surface which is the surface facing the pulp when the sliding lid is mounted on the mold box, and a perimeter side surface, which is a surface connecting the outer and inner surfaces. Preferably, the perimeter surface is substantially perpendicular to the inner and outer surfaces.

Preferably, the sliding cover is slidable along one or more side walls of the mold box to change the interior volume of the mold box.

Even more preferably, the walls of the casting box and the sliding cover are in contact over the entire surface around the perimeter. Thus, the size of the side walls of the mold box and the lid preferably match to allow contact between the perimeter surface and the side walls of the mold box at substantially all points.

Preferably, the sliding cover is placed facing the hole formed in the lower part of the casting box, and preferably also faces the movable support. Preferably, the sliding cover is substantially horizontal.

Preferably, the perimeter surface may include sealing elements to tightly close the mold box with a sliding lid. Sliding of the sliding lid is also possible when the mold box is tightly closed. The sealing member can be attached to the part of the sliding cover located inside the mold box and is used to hermetically seal the gap between the side walls of the mold box and the sliding cover.

Sliding of the sliding cover along the side walls of the casting box can also be ensured by the fact that the cover floats freely on the pulp, i.e. the sliding cover moves up and down depending on the position of the pulp level, so that the sliding cover floats on the surface of the pulp, and if the pulp level rises, the cover also moves up.

In addition, the sliding cover can be removed to open or close the top of the mold box.

The sliding cover can be actuated by a suitable actuating element and thus it can function as a pontoon roof that is placed on top of the casting box to slide vertically under the pressure of the slurry supplied to the casting box.

Thus, the sliding lid may be in contact with the pulp, or there may be an air gap between the pulp and the lid.

The presence of a sliding cover allows you to control the pressure inside the casting box. The presence of a sliding cover allows you to get a container under pressure. The ability to move the sliding cover allows you to place different amounts of pulp in the casting box or also set different pressures. The sliding cover can also prevent the formation of "dry spots" of the pulp on the surface of the pulp in contact with air.

The presence of a sliding cover may allow control of the pressure and flow of the pulp within the casting box. This control has minimal influence or impact on the casting process, namely it does not change (or only minimally changes) the conditions in the casting gap between the surfaces of the movable support and the molding blade, while ensuring the proper mixing effect of the pulp that naturally moves inside casting box.

The use of a sliding cover avoids direct contact between the pulp and air, which minimizes oxidation and chemical/biological reactions in the pulp, including fermentation, mainly in places where the pulp moves slowly and/or remains stationary for a long period of time.

Preferably, the perimeter surface may include a sealing element for sealing the mold box with a sliding lid. Preferably, the sealing element is a part of the perimeter surface, that is, the sealing element is located on the side of the sliding cover, in contact with the side walls of the mold box. This makes it easy to control the pressure in the mold box. Preferably, the interior volume of the mold box is tightly closed.

More preferably, the sealing element is coated with or made from graphene. Graphene allows both good sealing characteristics and free sliding of the sliding cover on the walls of the casting box, in particular for the pontoon cover.

Preferably, the sliding lid or mold box includes a pressure valve to control the pressure value within the mold box. The valve can be set to a certain pressure so that if the pressure inside the mold box is too high, the valve prevents overpressure by venting air and/or slurry from the mold box.

Preferably, the pressure inside the mold box is maintained in the range of 1 bar to 10 bar, more preferably 1 bar to 5 bar, even more preferably 1 bar to 3 bar.

Preferably, the casting box comprises a plurality of ribs, the ribs being connected to the sliding cover. Without being limited by theory, the pulp is likely to exhibit shear thinning, ie there is an inverse relationship between the natural viscosity of the pulp and the applied shear force. Thus, good mixing of the slurry inside the mold can be useful in the manufacturing process, in particular for controlling the thickness of the formed sheet. For this reason, ribs are preferably built into the casting box, which influence the flow of the pulp. The ribs, which may be shaped like blades, advantageously function as a mass spreader as well as static mixers, since the slurry must flow around these ribs during its flow, spreading and creating non-linear flows. Accordingly, the pulp performs a "complex local movement" around the ribs and at the same time a general global movement, and within this movement it flows and moves towards the forming blade.

In this way, the linear flow of the pulp is prevented, as far as possible, also in the area where the pulp passes through the thin gap between the forming blade and the movable support. Based on manufacturing experience, the longitudinal (with respect to the casting direction) linear flows of pulp entering the mold box and/or within the mold box can be associated with the linear transverse heterogeneity of the formed sheet of material, in particular with respect to its thickness, physical characteristics and visual appearance. The specific geometry, size, number, and relative proximity between the ribs allows you to specify their effect on the flow of the pulp. These parameters can be developed by computer simulation, taking into account the configuration of the casting box and the characteristics of the slurry.

Preferably, the ribs are attached to the sliding lid so that the sliding movements of the lid correspond to the sliding movements of the ribs. Attaching the ribs to the sliding cover allows them to be easily removed (together with the cover) for repair or cleaning. This also makes it easy to change their vertical position.

More preferably, the casting box contains an adjusting device for changing the orientation of the ribs, and the specified orienting device is located on the surface of the sliding cover, external relative to the casting box. The ribs may have an elongated shape in which they have a major longitudinal axis. It may be useful to be able to change the orientation of this main longitudinal axis depending on the parameters of the process or pulp. As an example, to effect such an adjustment, an adjusting device is located on the outer surface of the sliding cover.

Preferably, the casting box includes a pulp inlet, the pulp inlet being formed in one of the side walls. The introduction of the pulp from one of the side walls, instead of, for example, the introduction from above, can further improve the uniformity of the pulp, since it can minimize or limit the formation of air bubbles within the pulp itself. In addition, this eliminates the difficulty that the pulp supply tube passes through the movable cover. The introduction of additional pulp into the casting box through the inlet is preferably below a predetermined level of pulp in the casting box. Preferably, the predetermined pulp level in the mold box is maintained substantially constant at a certain height or within a certain height range. Thus, advantageously, during casting there is a continuous flow of new pulp, which is transferred to the casting box through a suitable tube. If the pulp is added in such a way that it falls onto the casting box, the pulp falling through the air can contain air bubbles, which can lead to defects in the cast web. When using an inlet located in the side wall below a predetermined pulp level, the formation of air bubbles is difficult.

Preferably, the sliding cover is substantially horizontal. More preferably, the sliding cover is in the form of a plate. Preferably, the outer and inner surfaces of the sliding cover are parallel and substantially horizontal.

The present invention also relates to a method for casting a web of material containing alkaloids, including: providing a casting box forming one or more side walls; providing a mold blade connected to the casting box; providing a movable support facing the forming blade; introducing pulp into the casting box to a certain level; covering the casting box with a sliding cover floating on the pulp, such that the position of the sliding cover changes with a change in the level of the pulp in the casting box or with a change in the pressure value in the casting box; and forming the pulp on the movable support using a forming blade to form a web of material containing alkaloids.

The advantages of the method according to the present invention have already been described above and are not repeated.

The sliding cover can float on the pulp in such a way that it follows changes in pulp height.

Preferably, the method includes the step of tightly closing the mold box with a sliding lid. Preferably, the tight closing is effected by means of a sealing element on the surface around the perimeter of the sliding cover.

Preferably, the method according to the present invention includes the step of changing the pressure inside the mold box. The amount of pressure inside the casting box can be adjusted by sealing the sliding cover. The pressure can be changed by changing the position of the sliding cover or by adjusting one or more pressure valves. Preferably, the inside of the mold box is maintained at a pressure in the range of 1 bar to 10 bar, more preferably 1 bar to 5 bar, even more preferably 1 bar to 3 bar.

Preferably, the method includes the step of providing a plurality of fins attached to the sliding cover. Preferably, said ribs are attached to the inner surface of the sliding cover in such a way that they are in contact with the pulp during the flow of the pulp to the forming blade.

Preferably, the method includes the step of changing the orientation of the ribs. Depending on the geometry of the casting box, the characteristics of the pulp and the desired characteristics of the cast web, it is possible to change the orientation of the ribs accordingly.

Preferably, the step of introducing the pulp into the mold box includes the step of introducing the pulp into the mold box along the feed direction, the feed direction forming an angle with the horizontal plane of -45 degrees to +45 degrees.

Substantially horizontal pulp feeding can prevent "gravity effect" and related flow changes during pulp feeding, achieve better mixing effect associated with ribs, and simplify the overall structure of the mold box by eliminating components and structural elements, and simplifies cleaning.

Preferably, the shaped sheet of alkaloid-containing material comprises a homogenized tobacco sheet.

The present invention may also relate to a foundry for casting a web of material, comprising: a casting box configured to receive pulp to be cast to form a web; moreover, the specified casting box forms one or more side walls; a sliding cover configured to slide along one or more side walls of the mold box, thereby changing the internal volume of the mold box; movable support; and a forming blade configured to form the pulp contained in the casting box on the moving support to form a cast web.

The present invention may also relate to a method for casting a web of material, including: providing a mold box forming one or more side walls; providing a mold blade outside the mold box; providing a movable support facing the forming blade; introducing pulp into the casting box to a certain level; covering the casting box with a lid floating on the pulp, such that the position of the lid changes with a change in the pulp level in the mold box or with a change in the pressure value in the mold box; and molding the pulp on the movable support with the mold blade to form a web of material.

Other advantages of the present invention will become apparent from its detailed description with non-limiting reference to the accompanying drawings, in which:

On FIG. 1 shows a schematic side sectional view of a first embodiment of a plant for producing a web of material containing alkaloids;

On FIG. 2 shows a schematic side view in section of a part of the apparatus of FIG. 1; And

On FIG. 3 shows a schematic side view in section of a detail of the plant of FIG. 2.

With reference to Figures 1 and 2, a first embodiment of a foundry for the production of a cast web from an alkaloid-containing material according to the present invention is presented and designated with reference numeral 100. Figures 1 and 2 show only part of the casting plant 100.

The casting machine 100 is designed to produce a cast web from homogenized tobacco material 1.

The casting machine 100 includes a casting box 10 containing the pulp 2 and a movable support 20, wherein the forming blade 70 molds the pulp 2 contained in the casting box 10 on the movable support 20 to form a molded sheet 1 of homogenized tobacco material.

The slurry 2 from the buffer tanks (not shown in the drawings) is transferred to the casting box 10 by means of a pump (not shown in the drawings). Preferably, the pump includes a flow controller (not shown in the drawings) to control the amount of slurry 2 fed into the mold box 10. The pump is advantageously designed to maintain the minimum required time for slurry transport. The pump is connected in a fluid medium, for example, by a pipeline 90 (see Fig. 2), with a casting box 10 with the possibility of feeding pulp 2 into it.

The mold box 10 includes side walls including first and second opposing walls 12, 14. The mold blade 70 is connected to the mold box 10 at a second wall 14. The mold box 10 is typically delimited by four side walls, namely the first and second opposing walls 12, 14 and third and fourth opposite walls (not shown in the figures) that connect the first and second opposite walls 12, 14.

The amount of slurry 2 in the mold box 10 is at a predetermined level, which is preferably maintained substantially constant so that the pressure generated by the slurry column 2 remains substantially constant. In order to maintain the amount of slurry 2 at a substantially constant level, said pump controls the flow of slurry 2 entering the casting box 10.

The movable support 20 comprises, for example, a continuous stainless steel belt 7 with a drum assembly. Said drum assembly includes a main drum 21 located below the casting box 10, which moves a movable support 20. Preferably, the casting box 10 is mounted on top of the main drum 21.

The pulp is formed on the steel belt 7 - at the level of the drum 21 - by means of a forming blade 70, resulting in a continuous sheet 1 of homogenized tobacco material. In order for the pulp to reach the molding blade and, accordingly, the movable support, the casting box 10 has an opening 17 in its bottom region, and this opening 17 extends across the width of the casting basket 10. The opening 17 is located above the drum 21 and close to it.

The movement of the steel belt 7 advances the pulp 2 towards the forming blade 70 at the front exit 18 of the casting box 10 (on the second wall 14). This flow is indicated by arrow 13 in FIG. 1. The mold blade 70 forms part of the pulp 2 on the steel belt 20 while the rest of the bulk of the pulp 2 is returned and recirculated inside the casting box 10. The steel belt 20 moves in the casting direction shown by arrow 24 in FIG. 1.

The mold blade 70 has a base dimension which is its longitudinal width. The mold blade 70, for example, is substantially rectangular. The mold blade 70 is attached to the mold box 10 by means of an adjustable panel 8 actuated by an actuator 9 (shown in FIG. 2), which allows precise control of the position of the mold blade 70.

Between the forming blade 70 and the steel belt 20 there is a gap, the dimensions of which determine, among other things, the thickness of the cast web of homogenized tobacco material.

The casting box 10 according to the present invention also includes a sliding cover 80. Next, with reference to FIG. 2, the sliding cover comprises an inner surface 81 facing or in contact with the pulp, an outer surface 82, and a perimeter surface 83. The perimeter surface 83 is in contact with the side walls 12, 14 of the mold box 10. Preferably, the perimeter surface 83 is in contact with all side walls. The size of the inner surface 81 is such that it preferably corresponds to the area defined by the side walls of the mold box 10.

Sliding lid 80 can be slid along the side walls by sealing elements 84 made of graphene and located on the surface along the perimeter 83. The presence of graphene sealing elements 84 ensures that the mold box 10 is tightly closed by the sliding lid to form a pressurized vessel. A valve (or more than one valve) 23 is located on the outer surface 82 of the sliding cover to enable the pressure value inside such a pressure vessel to be changed. The maximum value of the allowable pressure can be adjusted by the valve 23.

In addition, the first and second rows 25, 26 of ribs extend from the inner surface 83 of the sliding cover to the pulp 2. These two rows of ribs are preferably parallel to each other and attached to the sliding cover 80. On the opposite side of the cover containing the fins, i.e. on the outer surface 82, first and second controls, both designated 22, are available to the user and can be used to rotate the ribs 25, 26. The controls 22 may include control knobs.

On FIG. 3 shows an enlarged bottom view of the rows of ribs. Each rib 25, 26 is C-shaped, with the concave surface of this C oriented substantially towards the main pulp flow direction. In other words, the ribs 25, 26 are all the same shape and all have a major dimension, with the major dimensions of the ribs within the same row substantially parallel to each other.

The mold box 10 further comprises a conduit 90 (only visible in FIG. 2) for conveying the pulp 2 inside the mold box 10. The conduit 90 defines an inlet 91 formed in the side wall 12 of the mold box 10. The inlet 91 is essentially an opening in the side wall . Preferably, the conduit is arranged substantially horizontally, so that in the opening formed by the conduit on the side wall, i. inlet 91, the direction of pulp flow is substantially horizontal.

The casting machine 100 functions as follows. Pulp 2, preferably obtained by mixing and combining tobacco powder and other ingredients, is transferred from a storage tank (not shown) by means of, for example, built-in agitators of the production line (also not shown), to the casting plant 100 and, in particular, to the inside of the casting box. 10.

The slurry 2 is fed through conduit 90 which is located on the rear upstream side of the mold box 10 (near the first wall 12 of the mold box 10), and the mold blade 70 is located on the forward downstream side of the mold box 10 (near second wall 14 of the casting box 10). In the direction of casting 24, the slurry must pass through two rows of ribs 25, 26, which are located essentially in the middle of the casting box 10, between the first and second walls 12, 14. The flow is controlled by acting on the control device 22, which can change the orientation of the ribs 25, 26 .

The pressure inside the mold box 10 is controlled by the position of the sliding cover 80, which can be raised or lowered in the vertical direction indicated by arrow 85 in FIG. 2 and control valve 23, or due to the fact that the cover floats freely on the pulp 2.

The step of forming the pulp 2 into a homogenized web 1 with a uniform and constant film thickness is carried out on a movable support 20, for example, on a stainless steel belt 7. In addition, it preferably includes monitoring the level of the pulp in the mold box 10, the humidity of the pulp inside the mold box 10 and the density of the pulp 2 using appropriate sensors.

The thickness of the web 1 of homogenized tobacco material and the grammage, monitored by a nucleon sensor immediately after molding, are continuously measured and feedback controlled by a pulp measuring device. Forming is carried out by means of a forming blade 70 forming a gap with the movable support 20, and this gap can also be adjusted with feedback.

Next, the cast web 1 is subjected to a drying step using a dryer (not shown in the drawings). The dryer comprises a plurality of separate drying zones. Each drying zone preferably has steam heating on the underside of the support and heated air above the movable support 20, and preferably adjustable air release controls. Inside the dryer, the homogenized tobacco web 1 is dried to the desired final moisture content on a support 20.

The drying step preferably includes uniform and gradual drying of the cast web 1 in a stainless steel endless belt dryer with separately adjustable zones. During drying, a step of monitoring the temperature of the cast web 1 in each drying zone is preferably carried out to ensure a smooth drying profile in each drying zone. The cast web 1 is dried to the desired final moisture content on the steel belt 20, heating by means of a steam boiler from below and air drying from above. Each drying zone is equipped with steam flow and pressure controls, with air temperature and air flow fully adjustable to provide the desired drying profile and product processing time.

Preferably, at the end of the molding step and the drying step, the homogenized tobacco web is removed from the support 20. After the drying station, the cast web 1 is preferably surface treated at the proper moisture content. The cast web is preferably passed through a secondary drying process to further reduce the moisture content of the web 1 and provide the target or specification moisture. Preferably, in this second drying step, the cast web 1 is placed on the net in such a way that moisture can be easily removed from both surfaces of the web 1. After the drying step, the cast web 1 is preferably wound into one or more rolls in a winding step, for example original roll. This original roll can then be used to produce smaller rolls using the slitting process and forming small rolls. The smaller roll can then be used to produce aerosol generating articles (not shown).

Claims (26)

1. A foundry for casting a web of material containing alkaloids, containing: a casting box configured to receive casting pulp to form a web of material containing alkaloids, the casting box forming one or more side walls; a sliding cover configured to slide along one or more side walls of the casting box; movable support; And a forming blade configured to form the pulp located in the casting box on a movable support to obtain a cast web. 2. Casting machine according to claim 1, characterized in that the sliding cover contains a sealing element for tightly closing the casting box. 3. Casting plant according to claim. 2, characterized in that the sealing element is coated with graphene or made of it. 4. Casting plant according to claim 2 or 3, characterized in that the sliding cover or casting box contains a pressure valve for adjusting the pressure value inside the casting box. 5. A casting machine according to any one of the preceding claims, comprising a plurality of ribs, said ribs being connected to a sliding cover. 6. A casting machine according to claim 5, comprising an adjusting device for changing the orientation of the ribs, said adjusting device being located on a sliding cover surface external to the casting box. 7. A casting plant according to any one of the preceding claims, characterized in that the casting box comprises a pulp inlet provided in one of the side walls. 8. A casting machine according to any one of the preceding claims, characterized in that the sliding cover is substantially horizontal. 9. A method for casting a web of material containing alkaloids, including: providing a casting box forming one or more side walls; providing a mold blade connected to the casting box; providing a movable support facing the forming blade; introducing pulp into the casting box to a certain level; covering the mold box with a sliding lid floating on the pulp, such that the position of the lid changes as the pulp level in the mold box changes or pressure changes in the mold box; And molding the pulp on a movable support by means of a molding blade to form a web of material containing alkaloids. 10. The method of claim 9, comprising the step of tightly closing the mold box with a sliding lid. 11. The method according to claim 9 or 10, including the step of changing the pressure value inside the casting box. 12. The method according to any one of paragraphs. 9-11, including the steps of providing a plurality of ribs attached to the sliding cover. 13. The method of claim. 12, including the step of changing the orientation of the ribs. 14. The method according to any one of paragraphs. 9-13, characterized in that the stage of introducing the pulp into the casting box includes: introduction of the pulp into the casting box along the feed direction, wherein the feed direction forms an angle with the horizontal plane, ranging from -45 to +45°. 15. The method according to any one of paragraphs. 9-14, which includes the step of maintaining the pressure value inside the casting box in the range from 1 to 10 bar.

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