RU2812694C2 - Method and installation for casting sheet from alkaloid-containing material - Google Patents

Abstract

FIELD: sheet casting.

SUBSTANCE: group of inventions related to a method for casting a sheet from a material containing alkaloids and a casting installation for producing sheets from a material containing alkaloids. The method for casting a sheet of alkaloid-containing material includes producing a suspension of alkaloid-containing material characterized by a viscosity value; storing the suspension in the first reservoir; providing a first flow path and a second flow path for fluid communication between the first reservoir and the injection moulding box, the first flow path comprising a first pump and the second flow path comprising a second pump; directing the slurry along either a first flow path or a second flow path from the first reservoir to the casting box to create a slurry flow along the first flow path or the second flow path based on the viscosity value of the slurry; and casting the slurry to form a sheet of alkaloid-containing material.

EFFECT: possibility to deliver suspensions with different viscosity values to the casting box with an adapted flow rate, as a result, the quality of casting is improved.

15 cl, 4 dwg

Description

The present invention relates to a casting machine and a casting method for producing a cast sheet from an alkaloid-containing material.

In particular, the alkaloid-containing material is a homogenized tobacco material, preferably used in an aerosol-generating product, such as a cigarette or a "heat-not-burn" tobacco-containing product.

Currently, in the production of tobacco products, in addition to tobacco leaves, homogenized tobacco material is also used.

In a "heated-no-combustion" aerosol-generating product, the aerosol-forming substrate is heated to a relatively low temperature to produce an aerosol while preventing combustion of the tobacco material. In addition, the tobacco present in the homogenized tobacco material is typically solely tobacco or contains a major portion of the aerosol-forming substrate of said heated-non-combustion aerosol-generating article. This means that the aerosol composition generated by such a "heat-not-burn" aerosol-generating article is essentially based on only homogenized tobacco material. Therefore, it is important to ensure proper control of the composition and mechanical characteristics of the homogenized tobacco material, such as the flavor of the aerosol.

Homogenized tobacco material is produced by mixing different components, including tobacco powder, to form a tobacco slurry. This slurry is then stored in tanks before being sent, via a suitable delivery system, to a casting system where it enters a “casting box” for casting onto a moving steel conveyor belt, followed by drying in a dryer.

To ensure continuous and uniform casting, a certain amount of slurry is preferably required in the casting box. Alternatively or additionally, substantially constant pressure within the casting box is preferred to ensure continuous and uniform casting. It has been found that the uniformity and quality of the cast sheet can also be affected by the amount of slurry and the pressure in the casting box. In order to control the amount of slurry delivered to the casting box, the delivery system that connects the slurry reservoir to the casting box typically includes a pump and a control loop. In said control loop, the flow rate of the slurry pumped from the slurry tanks is adjusted in accordance with the measured flow rate of the slurry leaving the casting box.

However, this control may not be accurate in the case of a suspension with a density that varies from one batch to another or within a batch. The density of the suspension may change, for example, due to chemical reactions in the suspension, such as gelation. Indeed, in the case of large density fluctuations, the pump may be unable to deliver the required flow rate to the injection molding box.

There is a need for a casting machine and a casting method for producing a cast sheet of an alkaloid-containing material that can adapt to changes in slurry characteristics. In addition, it would be useful to have a casting machine and casting method with proper control of the flow rate of the slurry supplied to the casting box.

US 2007/084476 describes a process for producing reconstituted tobacco material, comprising preparing a heated mixture of water and sugar; providing a liquid flavor such as menthol; mixing tobacco particles, water and adhesive binder with a mixture of water and sugar and flavoring in a paddle mixer to form a reconstituted tobacco mixture; and forming the reconstituted tobacco mixture, for example by casting or extruding the reconstituted tobacco mixture, into a reconstituted tobacco material. The temperature and viscosity of the mixture is controlled by adjusting the amount and temperature of water supplied to the paddle mixer. US 2007/084476 does not adapt to changes in the characteristics of the slurry entering the casting box, and does not regulate the flow rate (flow) of the suspension into the casting box.

The present invention relates to a method for casting a sheet of an alkaloid-containing material, comprising producing a suspension of the alkaloid-containing material having a viscosity value; storing the suspension in the first reservoir; providing a first flow path and a second flow path for fluid communication between the first reservoir and the injection molding box. The first flow path contains a first pump, and the second flow path contains a second pump. The method includes the step of directing a slurry along either a first flow path or a second flow path from a first reservoir to a casting box to create a slurry flow along the first flow path or a second flow path based on a viscosity value of the slurry. The method includes the step of slurry casting to produce a sheet of alkaloid-containing material.

The present invention also relates to an injection molding apparatus for producing a sheet of an alkaloid-containing material, comprising: a first tank for storing a suspension of the alkaloid-containing material; a casting box containing a casting device for casting a sheet of alkaloid-containing material; a viscosity evaluation unit for measuring or determining the viscosity value of the suspension; a first flow path fluidly connecting the first reservoir and the casting box for directing the flow of slurry into the casting box; a second flow path fluidly connecting the first reservoir and the casting box to direct the flow of slurry into the casting box; a first pump and a second pump, wherein said first pump is located within the first flow path and the second pump is located within the second flow path. The injection molding apparatus includes a first valve for selectively opening either a first flow path or a second flow path to allow slurry to flow from the first reservoir into the injection box through either the first flow path or the second flow path. The injection molding apparatus includes a control element for controlling a first valve to select either a first flow path or a second flow path based on the viscosity value of the slurry.

Suspensions having a wide range of viscosities can be used in the present invention. The viscosity of a suspension may vary from one formulation to another, or it may vary over time within the same formulation. Depending on the viscosity value, one or another flow path is selected for the suspension to flow from the reservoir to the injection box. The flow path is selected to allow the use of a suitable pump for a given slurry density, for example a pump capable of delivering the slurry at the required flow rate to the casting box. In this way, it is possible to ensure that suspensions having different viscosities are delivered to the injection box with an adapted flow rate.

As used herein, the term "sheet" refers to 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 about 30 millimeters. Even more preferably, the sheet width is from about 60 millimeters to about 300 millimeters. The sheet thickness is preferably from about 50 micrometers to about 300 micrometers, more preferably the sheet thickness is from about 100 micrometers to about 250 micrometers, and even more preferably from about 130 micrometers to 220 micrometers.

As used herein, the term “suspension” refers to a liquid-like, viscous or paste-like material, which may comprise an emulsion of various liquid-like, viscous or paste-like materials. The suspension may contain a certain amount of solid particles, provided that the suspension still exhibits the behavior of a liquid-like, viscous or paste-like material.

In the following description, reference is made to the direction of flow of the suspension by the terms "upstream" and "downstream".

As used herein, the term "movable support" means any means comprising a surface and configured to move in at least one longitudinal direction. The movable support can form a closed loop so as to allow continuous transport in one direction. However, the movable support can also be driven in a reciprocating manner. The movable support may include a conveyor belt. The movable support may be substantially flat, and it may have a structured or unstructured surface. The movable support may be completely liquid-tight. This prevents the slurry from accidentally passing through the support. In other embodiments, the movable support may include holes in its surface. Preferably, said openings are of such a size that they are permeable to air but impermeable to liquid. Such openings provide the possibility of improving the removal of moisture from the slurry applied to the movable support by allowing water vapor to escape also through the movable support, and not only through the outer surface of the cast sheet formed by the slurry. During drying, the suspension tends to form an outer dry layer. The outer dry layer may form a barrier to the escape of moisture from the suspension below the outer dry layer. Accordingly, providing holes in the movable support allows for more uniform drying of the slurry throughout the entire thickness of the sheet being cast. The movable support may comprise a sheet-shaped movable and flexible strip. 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 tape can be made of heat-resistant material so that it can be heated to speed up the drying process of the suspension.

"Alkaloid-containing 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 naturally occurring chemical compounds that usually contain nitrogen atoms as bases. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds with similar structures are also called alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulfur and, less commonly, other elements such as chlorine, bromine and phosphorus.

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

As used herein, the term “homogenized tobacco material” refers to a material resulting from the agglomeration of particulate tobacco that contains the alkaloid nicotine. Thus, the alkaloid-containing material may be a homogenized tobacco material.

The most widely used forms of homogenized tobacco material are reconstituted tobacco leaf and cast leaf. The process of making sheets of homogenized tobacco material typically involves mixing tobacco powder and a binder to form a slurry. The suspension is then used to create tobacco leaf. For example, a viscous slurry is cast onto a moving metal belt to produce a so-called cast sheet. In an alternative embodiment, a low viscosity, high water content slurry can be used to produce reconstituted tobacco in a process similar to papermaking.

Tobacco sheet material may be called reconstituted sheet material and is formed using particulate tobacco (eg, reconstituted tobacco) or a particulate tobacco mixture, a humectant and an aqueous solvent to form a tobacco composition.

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

The term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds that can form an aerosol. Generally, the aerosol is suitable for inhalation by the user. Typically, aerosol-forming substrates release volatile compounds when heated. The aerosol-forming substrate may include a material containing volatile alkaloid flavor compounds that are released from the aerosol-forming substrate when heated. The aerosol-forming substrate may comprise homogenized material.

As used herein, the term “aerosol generating device” refers to a device configured to interact with an aerosol-forming substrate to generate an aerosol. Preferably, the aerosol generating device comprises an aerosol generator, such as a heater.

Said alkaloid-containing material sheet can be used as an aerosol-forming substrate for an aerosol-generating device.

The suspension may contain several different components or ingredients. These components can affect the properties of the cast sheet of alkaloid-containing material. The first ingredient is an alkaloid-containing material, for example in powder form. This material may be, for example, a tobacco powder mixture. Preferably, the tobacco powder mixture contains the majority of the tobacco present in the pulp. Thus, the tobacco powder mixture is the source of the bulk of the tobacco in the homogenized tobacco material. Thus, the tobacco powder mixture determines the taste/aroma of the final product, such as an aerosol, created by heating the homogenized tobacco material.

The binder is preferably added to improve the tensile properties of the homogenized sheet. An aerosol-forming agent is preferably added to promote aerosol formation. In addition, in order to achieve a certain viscosity and humidity when casting a web from a material containing alkaloids, water can be added to the suspension.

The amount of binder added to the slurry may range from about 1 percent to about 5 percent by dry weight of the slurry. More preferably, it is in the range of about 2 percent to about 4 percent. The binder used in the pulp may 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. Although any binder can be used, preferred binders are natural pectins such as fruit, citrus or tobacco pectins; guar gums such as hydroxyethylguar and hydroxypropylguar; 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; pullalon; konjac flour; xanthan gum, etc. A particularly preferred binder for use in the present invention is guar.

Cellulose pulp containing cellulose fibers is preferably added as a strengthening agent to the slurry to increase the tensile strength of the alkaloid-containing material web. Typically, the addition of cellulose fibers to the suspension, acting as a strengthening agent, increases the tensile strength of the tobacco material web. Therefore, the addition of cellulose fibers makes it possible to increase the elasticity of the homogenized tobacco material web. Cellulosic fibers included in the slurry to produce homogenized tobacco material are known in the art and include, but are not limited to: softwood fibers; hardwood fibers; jute fibers; flax fibers; tobacco fibers and their combinations. In addition to pulping, cellulosic fibers may be subjected to suitable treatment processes such as refining, mechanical pulping, chemical pulping, bleaching, kraft pulping and combinations of the above. The cellulosic fibers may contain materials from tobacco stems, veins, or materials from other parts of 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 in conjunction with or as an alternative to these fibers. The average 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. Moreover, preferably, the amount of cellulose fibers is from about 1 percent to about 7 percent, on a dry weight basis, of the total weight of the slurry (or homogenized tobacco leaf).

The average length of the fibers refers to their actual length (whether they are twisted or bent) as measured by the MORFI COMPACT instrument marketed by Techpap SAS. Average length is the mathematical average of the fiber length measured by the MORFI COMPACT instrument when measuring N fibers, where N > 5. The MORFI COMPACT is a fiber analyzer that measures the length of fibers along the fiber structure, thereby measuring their actual unfolded length. Measured objects are considered fibers if their length is between 200 microns and 10,000 microns, and their width is between 5 microns and 75 microns. Fiber lengths are measured by adding deionized water to the fibers and using Morfi software.

The fibers in the substrate sheet may be woven or non-woven. In the case of non-woven fibers, they may be oriented predominantly in one direction. In addition, the fibers can be oriented, for example, randomly. In the case of interwoven fibers, various patterns can be used.

Suitable substances for forming an aerosol for inclusion in the pulp for alkaloid-containing 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; polyhydric alcohol esters 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 aerosol-forming agent content of the suspension may be greater than about 5 percent on a dry weight basis. The aerosol-forming agent content of the suspension may range from about 5 percent to about 30 percent on a dry weight basis. More preferably, the aerosol forming agent is present in an amount of from about 10 percent to about 25 percent based on the dry weight of the suspension. More preferably, the aerosol forming agent is present in an amount of from about 15 percent to about 25 percent based on the dry weight of the suspension.

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 cellulose fibers are included in a weight ratio of from about 1:1 to about 3:1.

The binder and aerosol forming agent are preferably included in a weight ratio of from about 1:30 to about 1:1. More preferably, the binder and aerosol forming agent 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 aerosol forming agent and tobacco particles are preferably included in a weight ratio of about 1:20 to about 1:1. More preferably, the aerosol forming agent and tobacco particles are included in a weight ratio of from about 1:6 to about 1:2.

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

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

The suspension is prepared at a given location and then stored. For example, the slurry may be stored and produced in the same location, such as the same tank, or in two different locations, such as two different tanks. The reservoir used is preferably known in the art. In addition, the slurry may be produced or stored in a single tank or in multiple tanks. In the following, the reservoir in which the suspension is stored and possibly also produced will be referred to as the first reservoir. If more than one tank is used, they will be referred to as the second tank, third tank, and so on.

From the reservoir in which it is stored, the suspension is transferred to a casting box for the purpose of casting a sheet of alkaloid-containing material. The cast sheet may be formed on a movable support which moves along the direction of casting so as to form a continuous sheet or web of alkaloid-containing material.

Casting is carried out using any known casting device, for example slurry casting can be carried out using a casting paddle. Extrusion of the suspension onto a movable support is possible. It is possible to spray the suspension onto the movable support. It is possible to spread the suspension on a movable support. The injection device is preferably connected to the injection box.

The casting box is preferably box-shaped. Preferably, the casting box has walls. More preferably, said walls in turn include side walls. The side walls may include first and second pairs of opposing walls, referred to as first, second, third and fourth side walls. The side walls are preferably substantially vertical, or they are inclined relative to a vertical plane. The side walls may be curved. The first and second side walls and the third and fourth side walls face each other. Preferably, the walls of the casting box also include a bottom wall which has an opening. Preferably, the entire bottom wall forms an opening. The injection box may include a lid so that it forms a pressure chamber. The internal pressure in the pressure chamber can be adjusted. In some embodiments, the injection box is open at the top.

Transfer of the slurry from the first reservoir to the casting box is accomplished along a flow path, such as a suitable piping, such that the first reservoir and the casting box are in fluid communication to allow the suspension to be transferred from the first reservoir to the casting box. Preferably, the slurry is continuously supplied from the first reservoir to the casting box for at least the majority of the production time during which the slurry is cast onto the movable support.

Preferably, the amount of slurry in the casting box is kept substantially constant. For example, the amount of slurry in the casting box is equal to a predetermined amount. Preferably, said predetermined amount of slurry is maintained in the casting box at all times. For example, a given level of suspension is set in the casting box. In order to obtain a substantially constant level of slurry in the casting box, the slurry is continuously fed into the casting box while simultaneously casting the slurry onto the movable support.

The flow path from the reservoir to the injection molding box includes a first flow path and a second flow path. Each of the first flow path and the second flow path connects the reservoir to the injection molding box. The first flow path and the second flow path can be completely separated. For example, each of the first flow path and the second flow path may include a separate inlet located in the reservoir, a separate outlet located in the mold box, and a separate path between the inlet and outlet. Alternatively, the first flow path and the second flow path may have a common section. For example, a reservoir may have one outlet (eg, one opening), and one common path of a given length that extends from said outlet and then splits into two different paths leading to two different inlets in the mold box. Conversely, the first tank may have two separate outlets, from which two different paths pass, which are then combined into a single path, terminating in a single inlet in the casting box. In addition, there may be one output and one input with a first common path that branches off from the output and then bifurcates into two paths that are then recombined into one common second path terminating at said input. Thus, the first flow path and the second flow path represent are two flow paths from the first reservoir to the casting box that are at least partially different from each other, but which may also have common areas or sections. Thus, the first flow path directs the slurry from the first reservoir to the casting box along a first route, and the second flow path directs the suspension from the first reservoir to the casting box along a second route that is at least partially different from the first route.

The first flow path includes a first pump, and the second flow path includes a second pump. The first pump and the second pump are located in those portions of the first flow path and the second flow path that are not common, that is, the first pump pumps slurry into the casting box only if the suspension is directed into the casting box along the first flow path and the second pump pumps slurry only if the slurry flows into the casting box along a second flow path. Just one pump or both pumps may be immersed in the slurry they are pumping, or they may be placed outside the slurry. According to the present invention, the first pump is a different pump from the second pump. Preferably, at least the characteristic of the first pump is different from that of the second pump. For example, the first pump may be a different type of pump than the second pump. The second pump may have a maximum power input higher than that of the first pump.

In the case of more than one slurry storage tank, additional flow paths may be present directing slurry from different tanks to the casting box using different pumps. Alternatively or additionally, also with one reservoir, more than two different flow paths can be provided, each of which has a different pump.

Additionally, if there are multiple reservoirs, a flow path connecting one reservoir to a casting box and another flow path connecting another reservoir to a casting box may share a pump. Given a first reservoir having a first flow path containing a first pump and a second flow path containing a second pump, the first pump and the second pump may be shared by other flow paths connecting the other reservoirs to the casting box. For example, a second reservoir is provided comprising a third flow path and a fourth flow path, both of which flow paths connect the second reservoir to the injection molding box. The third flow path may share the first pump with the first flow path, that is, the first flow path and the third flow path share a common section, and the fourth flow path may share the second pump with the second flow path, that is, the second flow path and the fourth flow path will share general section.

In order for the slurry to reach the casting box in a given time interval, it flows along either the first or second flow path, but not both at the same time. Alternatively, if there are common areas between two flow paths, then the suspension will pass through those common areas in all cases. Therefore, the slurry is directed along either the first or second flow path, for example, by actuating a valve or multiple valves that opens or closes the first or second flow path.

If the suspension passes through the first flow path, then it is moved by the first pump. If the suspension passes through the second flow path, it is moved by a second pump.

The choice between the first flow path and the second flow path is made based on the viscosity value of the suspension. The viscosity of a fluid is a measure of its resistance to deformation at a given speed. There are two related measures of viscosity called dynamic viscosity and kinematic viscosity. Dynamic viscosity is an indicator of internal resistance. Dynamic viscosity is the tangential force per unit area required to move one horizontal layer relative to another layer at a unit speed while maintaining a unit distance in a fluid.

In the International System of Units (SI system), the units of dynamic viscosity are N (Newton) s/m ² , Pa (Pascal) s or kg/(m s). Dynamic viscosity can also be expressed in the metric system CGS (centimeter-gram-second) as g/(cm*s), dyne s/cm ² or Poise (P). Poise is usually too large for practical use, so the unit is often divided by 100 to obtain a smaller unit, centipoise (cP), i.e. 1 P = 100 cP (centipoise).

Kinematic viscosity is the ratio of dynamic viscosity to density, that is, a value that does not include force. Kinematic viscosity can be obtained by dividing the dynamic viscosity of the fluid by the mass density of the fluid:

ν=μ/ρ

Where

ν=kinematic viscosity (m ² /s)

μ=dynamic viscosity (N s/m ² )

ρ=density (kg/m ³ )

In the SI system, the theoretical unit of kinematic viscosity is m ² /s or the commonly used Stokes (St), where 1 St (Stokes) = 10 ^-4 m ² /s = 1 cm ² /s.

The suspension viscosity in question may be either dynamic viscosity or kinematic viscosity. Preferably, the viscosity in question is a dynamic viscosity.

For example, the suspension may have a dynamic viscosity ranging from about 15,000 centipoise to about 45,000 centipoise. The viscosity of the suspension depends on the composition of the suspension; for example, the higher the water content of a suspension, the lower the viscosity of the suspension. The higher the tobacco content in the suspension, the higher the viscosity of the suspension. In addition, the viscosity of a suspension depends on its temperature and pressure. In addition, it depends on the homogeneity of the suspension.

Preferably, the viscosity of the suspension is assessed using a viscosity estimator. The viscosity estimator may comprise a viscometer. A viscometer measures the viscosity of a suspension. The preferred viscometers are rotational or vibration viscometers. The values given above as the viscosity range for the suspension were measured using a Proline Promass I 100 Coriolis viscometer/flow meter manufactured by Endress and Hauser AG.

Based on the viscosity value of the suspension, the suspension is directed into either a first flow path or a second flow path. In fact, preferably, the first flow path and the second flow path and, more preferably, the first pump and the second pump are suitable for a given slurry viscosity range. Preferably, one of the first flow path and the second flow path is better adapted for a given viscosity value. For example, the first pump and the second pump are optimized for different viscosity ranges. For example, the first pump may be adapted to handle "low viscosity" fluids, and the second pump may be adapted to handle "high viscosity" fluids. For example, the first pump may be suitable for a first range of viscosities, and the second pump may be suitable for a second range of viscosities. Preferably, the first range is different from the second range. Preferably, the first range includes viscosity values from about 15,000 centipoise to about 25,000 centipoise. Preferably, the second range includes viscosity values from about 20,000 centipoise to about 45,000 centipoise. In addition, other characteristics of the first flow path may differ from those of the second flow path. For example, a different path or pipeline may be used, which has, for example, different diameters or may be made of different materials. Other valves may also be used.

For certain suspension viscosities, both the first flow path and the second flow path may provide optimal results in delivering the suspension. In this case, the flow path is selected randomly between the first flow path and the second flow path, or the logic used makes the choice, for example, based on other factors.

Therefore, if a given slurry batch produced and stored in the first tank has a first viscosity value, then the first flow path may be selected. If the next batch of slurry has a second viscosity value different from the first, eg higher than the first, then the slurry can be directed along a second flow path.

This switching may be performed manually, for example by means of a manually operated valve(s) opening and closing the first flow path or the second flow path, or automatically by means of suitable actuators or control elements.

In addition, the viscosity of the suspension can be measured only once, and thus the selection of the flow path is carried out for the entire casting process. In other embodiments, the viscosity of the slurry may be measured multiple times or continuously, so that switching from one flow path to another may also be performed during casting.

Selecting the most appropriate flow path between the first and second flow paths depending on the density of the slurry makes it possible to obtain a substantially constant slurry flow rate in the casting box, regardless of the viscosity of the slurry. By selecting a pump suitable for a given viscosity, it is possible to achieve the required flow rate. Consequently, the casting quality improves. According to the present invention, it is possible to prevent equipment shutdowns. In addition, it is possible to reduce the variation in cast sheet thickness compared to systems without two different pumps. It is possible to easily regulate the pressure in the injection molding box. Adjustment of all these parameters makes it possible to improve the uniformity of the cast sheet.

In addition, damage to the first pump and the second pump is minimized by effectively selecting the appropriate pump for a given slurry viscosity. Cost reductions are possible because more economical pumps that can cover a specific viscosity range can be used compared to pumps that can cover wider viscosity ranges. In addition, the paths included in the first flow path and the second flow path may also be different. Various adapted paths provide the opportunity to reduce costs, as well as wear and damage to the material of the paths. For example, perhaps only some manufacturing processes require higher temperature or higher temperature preservation of the slurry, which in turn requires relatively expensive and specialized piping and pumps. These pipelines and pumps may only be present in the first flow path. In this case, a second pump and path system can be used for simpler production processes.

Preferably, the step of directing the slurry along either a first flow path or a second flow path from the first reservoir to the casting box based on a viscosity value of the slurry includes: setting a threshold viscosity value; directing the suspension along the first flow path if the viscosity value of the suspension is below a threshold viscosity value; and otherwise directing the slurry along the second flow path. Preferably, the first flow path is preferred for the "low viscosity slurry" and the second flow path is preferred for the "high viscosity slurry". Thus, a threshold viscosity value is selected that determines whether the slurry will be directed along the first flow path or the second flow path. An example threshold viscosity value may be approximately 23,000 centipoise.

Preferably, the viscosity of the suspension is measured or determined. More preferably, the suspension is characterized by its composition, and the method includes one or more of the following: measuring a viscosity value of the suspension in the reservoir; measuring the viscosity value of the suspension in the casting box; measuring the viscosity value of the suspension in the first or second flow path; determination of the viscosity value based on the composition of the suspension. The viscosity value of a suspension can be assessed in different ways and at different locations. For example, the viscosity value can be measured using a viscometer. Preferably, the viscometer may be placed in the first reservoir such that the viscosity is measured in the first reservoir. Alternatively or additionally, the viscosity of the slurry may be measured at a first flow path or a second flow path, such as at a portion of a path or conduit of the first flow path or the second flow path. In addition, the viscosity value may be measured at the casting box, for example at the inlet of the first flow path or the second flow path. The viscosity value can also be determined using other measurements, for example it can be calculated based on the composition of the suspension. Viscosity can also be determined by comparison with historical data.

According to some embodiments, the selection of the flow path along which the slurry will be directed, that is, the first flow path or the second flow path, is made at various possible times. The selection can be made in advance, that is, before the casting process begins, for example, based on the composition of the slurry batch. Based on the composition of the slurry, the viscosity of the slurry can be calculated and it can be determined whether it falls within the range of viscosities for which the first flow path is preferred or the range of viscosities for which the second flow path is preferred. Alternatively or additionally, the selection may be made in real time based on the measured speed of the pump being used (the pump associated with the selected flow path along which the slurry is being directed at that particular moment) and the corresponding slurry flow rate. At a given pump speed, a given slurry flow rate is expected. If the measured flow differs from what is expected, a decision can be made to change the flow path. Alternatively or additionally, selection can be made in real time based on the result of measuring the viscosity of the suspension. Measurements can be performed on the production line. In addition, measurements may be made in the tank or in the first flow path, or in the second flow path, or in the casting box. The measurements can be made, for example, using a viscometer that evaluates the kinematic viscosity of the suspension (or the dynamic viscosity of the suspension if the density of the suspension is known). Examples of suitable viscometers include, for example, a vibration viscometer, a capillary viscometer, a Zahn viscometer, or others. If the viscosity of the suspension changes, the selected flow path may also change.

More preferably, the method includes measuring or determining a viscosity value of the suspension more than once; and switching the flow of the slurry from the first flow path to the second flow path or vice versa if the viscosity value changes from the previous measurement or determination result. Preferably, a feedback loop is present. The viscosity value is measured several times, for example, at a given frequency. Based on the measurement results, or if the indicated changes are confirmed by more than one measurement result, the suspension is directed along a different flow path than the flow path along which the suspension was previously directed. The expression "based on measurement results" can mean, for example, the following: when there are changes in the viscosity value and, more preferably, when there are changes in the viscosity value that exceed a predetermined threshold value. The composition of the slurry or the type of slurry may change during production and, therefore, the selected flow path may change accordingly.

The composition of the suspension or the type of suspension may change during the production process, and therefore the selected flow path may change accordingly based on the results of monitoring the viscosity value of the suspension.

Preferably, the method includes: storing the suspension in a second reservoir; providing a third flow path for fluid communication between the second reservoir and the injection molding box, said third flow path comprising a third pump; connecting the second flow path to the second reservoir such that the second reservoir and the injection molding box are in fluid communication via the second flow path; directing the slurry along either a third flow path or a second flow path from the second reservoir to the casting box based on the viscosity value of the slurry. As mentioned above, the slurry may be stored in more than one reservoir, for example in a first reservoir and a second reservoir. Thus, each reservoir has a flow path leading to a casting box, the first flow path containing a first pump and connecting the first reservoir to the casting box, and the third flow path containing a third pump and connecting the second reservoir to the casting box. Preferably, the first pump and the third pump have substantially similar characteristics. Preferably, the first pump and the third pump are adapted for use with suspensions having substantially the same viscosity values. Additionally, the first reservoir and the second reservoir share a second flow path to direct the slurry from the first reservoir and the second reservoir to the injection box. In the second reservoir, the suspension is directed into either a third flow path or a second flow path, depending on the viscosity value of the suspension. In addition, each reservoir may also be fluidly connected to more than one injection box.

Preferably, the slurry is directed along the first flow path and the third flow path from the first reservoir and the second reservoir to the casting box at the same ranges of slurry viscosity values. Preferably, the slurry is directed along a second flow path, instead of a first flow path and a third flow path, from the first reservoir and the second reservoir to the casting box at the same slurry viscosities.

More preferably, the method includes: measuring or determining a viscosity value of the suspension more than once; switching both slurry streams from the first flow path and the third flow path to the second flow path or vice versa in the event of a change in the viscosity value compared to the previous measurement or determination result. Preferably, a feedback loop is present. The viscosity value is measured several times, for example, at a given frequency. Based on the measurement results, or if the specified changes are confirmed by more than one measurement result, the suspension is directed along a different flow path than the flow path along which the suspension was previously directed. The expression "based on measurement results" can mean, for example, the following: in the case of changes in the viscosity value, and more preferably in the case of changes in the viscosity value exceeding a predetermined threshold value. The composition of the slurry or the type of slurry may change during the production process, and therefore the selected flow path may also change accordingly.

Preferably, the flow rate is determined by the flow of slurry entering the casting box, and the method includes maintaining the flow rate of the slurry entering the casting box at a substantially constant level before and after the switch. Flow may be measured, for example, at the inlet of a flow path in a casting box.

Preferably, the first pump has the speed of the first pump and the second pump has the speed of the second pump. Preferably, the method includes: measuring the speed of the first pump or the speed of the second pump; measuring the flow rate of the suspension in the first flow path or in the second flow path; and switching the slurry flow from the first flow path to the second flow path or vice versa if the measured flow rate of the slurry in the first flow path or in the second flow path is outside the appropriate range for the corresponding measured speed of the first pump or the speed of the second pump. In case there is, for example, also a third flow path having a third pump, preferably the first pump has the speed of the first pump, the second pump has the speed of the second pump, and the third pump has the speed of the third pump. The method preferably includes: measuring the speed of the first pump, the speed of the second pump and the speed of the third pump; measuring the flow rate of the slurry in the first flow path, or the second flow path, or the third flow path; and switching both slurry streams from the first flow path or the third flow path to the second flow path or vice versa if the measured flow rate is outside a predetermined range for the corresponding first pump speed, second pump speed or third pump speed.

The speed of the first pump is measured. The speed of the second pump is measured. Measure the speed of the third pump, if available. The flow rate of the suspension in the first flow path is measured. The flow rate in the second flow path is measured. Measure the flow rate in the third flow path, if available. If the flow rate in the first flow path is outside the predetermined range for the measured speed of the first pump, then switch the slurry flow from the first flow path to the second flow path. If the flow rate in the third flow path is outside the predetermined range for the measured speed of the third pump, then switch the slurry flow from the third flow path to the second flow path. If the flow rate in the second flow path is outside the predetermined range for the measured speed of the second pump, then switch the slurry flow from the second flow path to the first flow path or the third flow path.

Pump speed refers to its rotation speed. Pumps typically contain a rotating mechanism to move the slurry. Therefore, pump speed refers to the speed at which the pump rotates, or the number of times it rotates per unit time. Different pumps may have different maximum speeds, above which the pump may fail or overheat. The pump may also be limited to maximum speed and its speed cannot be increased beyond maximum speed, for example for safety reasons. Therefore, if the speed of a given pump is outside the specified range, the slurry is directed to a different flow path than the flow path used to reach the casting box at the time the speed is measured. If the measured pump speed is outside the specified range, it may indicate that the slurry is too viscous for the pump in the flow path. In this case, it is preferable to use a different pump and therefore a different flow path. Preferably, the pump speed has a predetermined range that depends on the pump. For example, this range may include the maximum speed of the first pump, the maximum speed of the second pump, and the maximum speed of the third pump. This has the advantage of preventing the pump from reaching the maximum speed for a given pump.

Preferably, the first pump has the speed of the first pump and the second pump has the speed of the second pump. Preferably, the method includes: measuring the flow rate of a slurry exiting the casting chamber or entering the casting box or located in the first flow path or the second flow path; and changing the speed of the first pump or the speed of the second pump based on the measured flow rate of the slurry.

For example, if a third pump is present, then preferably the first pump, the second pump, or the third pump has a first pump speed, a second pump speed, or a third pump speed, and the method includes: measuring the flow rate of a slurry exiting a casting chamber or entering a casting box, or located on a first flow path or a second flow path or a third flow path; and changing the speed of the first pump, or the speed of the second pump, or the speed of the third flow based on the measured flow rate of the slurry.

If the slurry flow rate changes, it may also be necessary to change the pump speed to return the flow rate to the required value.

Preferably, the first pump or the second pump is a positive displacement pump. Preferably, the second pump includes a positive displacement piston pump in the second flow path where more of the "viscous slurries" are directed. Preferably, the second pump can be used for suspensions having a dynamic viscosity range from about 20,000 centipoise to about 45,000 centipoise. Preferably, the first pump can be used for suspensions having a dynamic viscosity range from about 15,000 centipoise to about 25,000 centipoise. Preferably, the first pump or the second pump comprises a vane pump. More preferably, the first pump or the second pump comprises a positive displacement pump.

Preferably, the first flow path or the second flow path comprises a conduit with a diameter of from about 2.5 centimeters to about 10.5 centimeters. Preferably, the first flow path or second flow path comprises a conduit for directing the slurry from the first reservoir to the casting box. Preferably, the pipeline is made of metal, more preferably the pipeline is made of stainless steel. The diameter of the pipeline is preferably selected depending on the viscosity of the suspension and the expected flow rate.

Preferably, said viscosity evaluation unit includes a viscometer. Preferably, the viscometer evaluates the kinematic viscosity. Alternatively, a viscometer estimates the dynamic viscosity of a suspension if the density of the suspension is known. Preferably, the viscometer is a vibration viscometer, a capillary viscometer, a Zahn viscometer or others.

Preferably, the installation comprises: a second reservoir; a third flow path fluidly connecting the second reservoir to the casting box for directing the flow of slurry into the casting box; a third pump located within a third flow path, the second flow path fluidly connecting the second reservoir and the casting box for directing a flow of slurry into the casting box; a second valve for selectively opening either a third flow path or a second flow path to permit flow of slurry from the second reservoir into the casting box along either a third flow path or a second flow path, said control element controlling the second valve such that the third path is selected flow or a second flow path based on the viscosity value of the suspension. As mentioned above, the slurry may be stored in more than one reservoir, such as a first reservoir and a second reservoir. Each reservoir preferably has its own flow path to the injection molding body, with the first flow path containing a first pump and connecting the first reservoir to the injection molding box, and the third flow path containing a third pump and connecting the second reservoir to the injection molding box. Preferably, the first pump and the third pump have substantially similar characteristics. Preferably, the first pump and the third pump are adapted for use with suspensions having substantially the same viscosity values. The first reservoir and the second reservoir preferably also share a second flow path, which second flow path should be used to direct the slurry from the first reservoir and the second reservoir to the casting box. The suspension is directed into the second reservoir either through a third flow path or a second flow path, depending on the viscosity value of the suspension. Thus, depending on the viscosity value of the suspension, the valve opens or closes to direct the suspension along the third flow path or second flow path.

Preferably, the first pump, second pump, or third pump has a first pump speed, a second pump speed, or a third pump speed, respectively. Preferably, the installation includes a speed controller for changing the speed of the first pump, or the speed of the second pump, or the speed of the third pump, respectively. In order to ensure a substantially constant flow rate, it is possible to vary the pump speed.

Specific embodiments will now be described by way of example only with reference to the accompanying drawings, in which:

in Fig. 1 is a schematic side view of an injection molding machine for casting a sheet of an alkaloid-containing material according to the present invention;

in Fig. 2 shows a second embodiment of the injection molding plant of FIG. 1;

in Fig. 3 shows a third embodiment of the installation of FIG. 1 and 2; And

in Fig. 4 shows an enlarged view of the details of the installations of FIG. 1-3.

In FIG. 1 shows, and designated by reference numeral 100, a first embodiment of an injection molding apparatus for producing a cast sheet from an alkaloid-containing material according to the present invention. In FIG. 1 only shows part of the injection molding plant 100.

In particular, the injection molding machine 100 is configured to produce a cast sheet from an alkaloid-containing material such as homogenized tobacco material 1.

The injection molding machine 100 contains a casting box 10 containing a suspension 2 and a movable support 20, wherein a casting blade 70 (see FIG. 4) casts the suspension 2 contained in the casting box 10 onto the movable support 20 to form a cast sheet 1 from homogenized tobacco material. Instead of the injection blade 70, any other injection device can also be used.

The injection molding apparatus 100 further includes a first reservoir 3, such as a tank or buffer reservoir, from which the slurry 2 is transferred to the injection molding box 10. The injection molding apparatus 100 includes a first flow path 4 and a second flow path 5 connecting the injection molding box 10 to the first reservoir 3, and a first pump 6 and a second pump 7 located respectively inside the first flow path 4 and the second flow path 5. Preferably, the first pump 6 and the second pump 7 include a flow regulator for controlling the amount of slurry 2 introduced into the casting box 10 along the first flow path or the second flow path. The first pump 6 and the second pump 7 are preferably configured to ensure that the periods of time during which the suspension is transferred are maintained at a minimum required level. The first reservoir 3 is fluidly connected through a first flow path 4 and a second flow path 5 to the casting box 10 so as to supply suspension 2 thereto.

The first pump 6 is different from the second pump 7. The first pump is suitable for operating with a first range of slurry viscosities. The second pump is suitable for operating with a second range of suspension viscosities. The second range is different from the first range.

Each flow path 4, 5 includes respective conduits 8 and two valves located upstream and downstream of their respective first and second pumps 6, 7. A first valve 21 and a second valve 22 are present in the first flow path 4 upstream and downstream of the first pump 6 respectively, and the third valve 23 and the fourth valve 24 are present in the second flow path 5 upstream and downstream of the second pump 7 respectively. The first valve 21 and the second valve 22 are used to enable the replacement of the first pump 6 in the first path 4 flow for cleaning or maintenance. The third valve 23 and the fourth valve 24 are used to allow the second pump 7 in the second flow path 5 to be replaced for cleaning or maintenance.

In the embodiment of FIG. 1, the first flow path 4 contains a first outlet 25 formed in and extends from the first reservoir 3, while the second flow path 5 contains a second outlet 26 formed in and extends from the first reservoir 3. Thus, for a given section of a first flow path and a given section of a second flow path that includes a first pump and a second pump, the first flow path is separated from the second flow path. Further downstream relative to the first pump 6 and the second pump 7, the first flow path 4 and the second flow path 5 of flow 5 are combined, so that the delivery of the suspension to the injection box 10 is carried out through one inlet 27.

In addition, the injection molding machine 100 includes a control element 50 configured to control the opening and closing of the first to fourth valves, namely valves 21, 22, 23, 24. The control element 50 may be a control unit such as a microprocessor or the like properly programmed.

The injection molding machine 100 may also include one or more viscometers, all of which are designated 60. The viscometer may be located in the first flow path and/or in the second flow path. Alternatively or additionally, a viscometer 60 may be located in the first reservoir 3 or in the casting box 10 for the purpose of measuring or determining the viscosity of the suspension. The viscometer 60, regardless of its position, is also connected to the control element 50.

The control element 50 is also configured to control the first pump 6 and the second pump 7 to regulate their characteristics, such as pump speed or pump flow.

The injection molding machine 100 also includes a flow sensor 80, illustrated for example located on one of the first flow path 4 or the second flow path 5. The flow sensor 80 can be located along one of the flow paths 4, 5 or on the injection molding box 10. The flow sensor 80 is also connected to the control element 50.

Let us now turn to Fig. 2, which shows a second embodiment of the injection molding apparatus 101. Reference numerals indicating the same or similar elements of the injection molding apparatus 100 according to the embodiment of FIG. 1, left unchanged.

The injection molding machine 101 includes a first tank 3 and a second tank 30. The first tank 3 and the second tank 30 may be identical or different. Preferably, the first tank 3 and the second tank 30 are identical to the first tank 3 of the first embodiment of the injection molding machine 100 of FIG. 1.

The injection molding machine 101 further includes a molding box 10 identical to that of the first embodiment of the injection molding machine 100, and it is described in detail below with reference to FIG. 4.

The injection molding machine 101 further includes a first flow path 4, a second flow path 5, and a third flow path 11 for connecting the injection molding box 10 to the first reservoir 3 and the second reservoir 30, the first flow path 4 connecting the first reservoir 3 to the injection molding box 10, and the third flow path A flow path 11 connects the second reservoir 30 to the injection molding box 10, while a second flow path 5 connects both of the first reservoir 3 and the second reservoir 30 to the injection molding box 10. Each of the first flow path 4, the second flow path 5 and the third flow path 11 contains a pump, namely the first pump 6, the second pump 7 and the third pump 9, respectively. Preferably, each of the first pump 6, the second pump 7 and the third pump 9 includes a flow regulator for controlling the amount of slurry 2 introduced into the injection box 10. The first pump 6, the second pump 7 and the third pump 9 are preferably configured to ensure that periods suspension movements were maintained at the minimum required level. The first reservoir 3 is fluidly connected through a first flow path 4 and a second flow path 5 to the casting box 10 so as to supply it with slurry 2. The second reservoir 30 is fluidly connected through a second flow path 5 and a third flow path 11 to the casting box 10 in such a way as to feed suspension 2 into it.

The first pump 6 is different from the second pump 7. The first pump is suitable for operating with a first range of slurry viscosities. The second pump is suitable for operating with a second range of suspension viscosities. The second range is different from the first range. The third pump 9 is substantially identical to the first pump 6. The third pump 9 is suitable for operating with a third range of slurry viscosities. The third range is equal to the first range.

The first flow path 4 and the third flow path 11 are similar to each other. Each of the first flow path and the third flow path includes two valves located upstream and downstream of their respective first pump 6 and third pump 9. The first valve 21 and the second valve 22 are present in the first flow path 4, respectively upstream and downstream of the first pump 6 and the third pump 9. of the first pump 6. A fifth valve 31 and a sixth valve 32 are present on the third flow path 11, respectively upstream and downstream of the third pump 9. The first valve 21 and the second valve 22 are used to allow the first pump 6 to be replaced in the first flow path 4 for cleaning or maintenance. The fifth valve 31 and the sixth valve 32 are used to allow the third pump 9 in the third flow path 11 to be replaced for cleaning or maintenance.

In the embodiment of FIG. 2, each of the first flow path 4 and the third flow path 11 contains an output. The first flow path 4 contains an outlet 25 in the first reservoir 3 and extends from said outlet. The third flow path 11 includes an outlet 28 in the second reservoir 30. Thus, for a given portion of the first flow path and for a given portion of the third flow path, which contain the first pump 6 and the third pump 9, respectively, the first flow path is separated from the third flow path. Further downstream of the first pump 6 and the third pump 9, the first flow path 4 and the third flow path 11 are combined, so that the suspension is delivered to the injection box 10 through one inlet 27.

The second flow path contains two outlets, of which one outlet 26 is located in the first tank 3, and the other outlet 29 is in the second tank 30. From the two outlets 26, 29 there are two separate pipelines 8, which are combined upstream of the second pump 7. In each pipeline, a valve is provided, namely a seventh valve 33 and a third valve 23 located upstream of the second pump 7. Downstream of the second pump 7 is an additional valve, namely a fourth valve 24. Downstream of the fourth valve 24 is a second flow path 5 is combined with first flow path 4 and third flow path 11 so that delivery of slurry 2 to casting box 10 occurs through a single inlet 27. A third valve 23 and a seventh valve 33 located upstream of the second pump 7 and a fourth valve 24 located downstream of the second pump 7 are used to allow the second pump 7 to be replaced in the second flow path 5 for cleaning or maintenance.

In addition, the injection molding machine 101 includes a control element 50 for controlling the opening and closing of the first to seventh valves, namely valves 21, 22, 23, 24, 31, 32, 33. The control element 50 may be a control unit such as like a microprocessor or the like, properly programmed. In FIG. 2, the connection of control element 50 to various components is not shown for clarity.

The injection molding unit 101 may also include one or more viscometers, all of which are designated 60. The viscometer may be located in a first flow path, a second flow path, or a third flow path. Viscometers can be located along all flow paths. Viscometers can be located on two of the three flow paths. In addition or alternatively, a viscometer may be located in the first reservoir 3, in the second reservoir 30, or in the casting box 10 for the purpose of measuring or determining the viscosity of the suspension. The viscometer 60, regardless of its position, is also connected to the control element 50.

The control element 50 is also configured to control the first pump 6, the second pump 7 and the third pump 9 to regulate their characteristics, for example the speed of the pumps or the flow rate of the pumps.

The injection molding machine 101 also includes a flow sensor 80, shown, for example, located on one of the flow paths. The flow sensor 80 may be located along one of the first flow path 4, the second flow path 5, or the third flow path 11. Flow sensors can be located along all flow paths. Flow sensors can be located on two of the three flow paths. A flow sensor 80 may be located in the casting box 10 to measure the flow rate of the slurry at the inlet 27. The flow sensor 80 is also connected to the control element 50.

Let us now turn to Fig. 3, which shows a third embodiment of the injection molding apparatus 102. Reference numbers indicating the same or similar elements of the injection molding apparatuses 100, 101 according to the embodiments of FIGS. 1 or 2, left unchanged.

The injection molding machine 102 is similar to the injection molding machine 100 of FIG. 1. The injection molding machine 102 includes a molding box 10 identical to that of the first embodiment and the second embodiment of the injection molding machine 100, 101, and is described in detail below with reference to FIGS. 4.

The injection molding machine 102 is different from the injection molding machine 100 of FIG. 1 in that it contains an additional flow path in addition to the first flow path and the second flow path. An additional flow path connects the first reservoir 3 to the casting box 10, similar to the first flow path and the second flow path. The injection molding machine 102 includes a first flow path 4, a second flow path 5, and a fourth flow path 34 for connecting the casting box 10 to the first reservoir 3. Each of the first flow path, the second flow path, and the fourth flow path includes a pump, namely the first pump 6. a second pump 7 and a fourth pump 35. Preferably, the first pump 6, the second pump 7 and the fourth pump 35 include a flow regulator for controlling the amount of slurry 2 introduced into the injection box 10. The first pump 6, the second pump 7 and the fourth pump 35 are preferably configured with the ability to ensure that suspension transfer periods are maintained to the minimum required. The first reservoir 3 is fluidly connected through a first flow path 4, a second flow path 5 and a fourth flow path 34 to the casting box 10 so as to supply it with slurry.

The first pump 6 is different from the second pump 7. The first pump is suitable for operating with a first range of slurry viscosities. The second pump is suitable for operating with a second range of suspension viscosities. The second range is different from the first range. The fourth pump 35 is different from the first pump 6. The fourth pump 35 is different from the second pump 7. The fourth pump 35 is suitable for operating with a fourth range of slurry viscosities. The fourth range is different from the first range. The fourth range is different from the second range.

Each of the first flow path 4, the second flow path 5 and the fourth flow path 34 contains two valves located downstream and upstream of their respective first pump 6, second pump 7 and fourth pump 35. The first valve 21 and the second valve 22 are present in the first flow paths upstream and downstream of the first pump 6, respectively. A third valve 23 and a fourth valve 24 are present in the second flow path, respectively, upstream and downstream of the second pump 7. An eighth valve 36 and a ninth valve 37 are present in the fourth flow path 34, respectively, upstream and downstream of the fourth pump 35. The first valve 21 and the second valve 22 is used to allow the first pump 6 in the first flow path 4 to be replaced for cleaning or maintenance. The third valve 23 and the fourth valve 24 are used to allow the second pump 7 in the second flow path 5 to be replaced for cleaning or maintenance. An eighth valve 36 and a ninth valve 37 are used to allow the fourth pump 35 to be replaced in the fourth flow path 34 for cleaning or maintenance. In the embodiment of FIG. 3, the first flow path 4, the second flow path 5 and the fourth flow path 34 each have respective outlets 25, 26, 38 in the first reservoir 3 from which they extend. Downstream of the first pump 6, the second pump 7, and the fourth pump 35, the first flow path, the second flow path, and the fourth flow path are combined so that delivery of the slurry to the casting box 10 occurs through a single inlet 27.

In addition, the injection molding machine 102 includes a control element 50 for controlling the opening and closing of the valves 21, 22, 23, 24, 36, 37. The control element 50 may be a control unit such as a microprocessor or the like, suitably programmed. In FIG. 3, the connection of control element 50 to various components is not shown for clarity.

The injection molding unit 102 may also include one or more viscometers, all of which are designated 60. The viscometer may be located in a first flow path, or a second flow path, or a fourth flow path. Viscometers can be located along all flow paths. Viscometers can be located on two of the three flow paths. In addition or alternatively, a viscometer may be located in the first reservoir 3 or in the casting box 10 to measure or determine the viscosity of the suspension. The viscometer 60, regardless of its position, is also connected to the control element or block 50.

The control element 50 is also configured to control the first pump 6, the second pump 7 and the fourth pump 35 to regulate their characteristics, such as pump speed or pump flow.

The injection molding machine 102 also includes a flow sensor 80, shown, for example, located on one of the flow paths. The flow rate sensor 80 may be located along one of the first flow path 4, the second flow path 5, or the fourth flow path 34. Flow sensors can be located along all flow paths. Flow sensors can be located on two of the three flow paths. The flow sensor 80 may be positioned on the casting box such that the flow rate at the outlet of one of the flow paths is measured. The flow sensor 80 is also connected to the control element 50.

Let us now turn to Fig. 4, which shows a detailed view of the casting box 10. The casting box of FIG. 4 may be a casting box 10 used in any embodiment of the casting machine 100, 101, 102 of FIG. 1-3.

The casting box 10 contains four side walls. The injection molding box 10 includes first and second opposing walls 12, 14 and third and fourth opposing walls (not shown in the figures) that connect the first and second opposing walls 12, 14.

The casting blade 70 is connected to the casting box 10 on the second wall 14. The casting blade 70 is connected to the casting box 10 for the purpose of casting the slurry. The casting blade 70 has a basic dimension that is its longitudinal width. The injection blade 70 is, for example, substantially rectangular.

The molding blade 70 is attached to the casting box 10 by means of an adjustable panel 8 actuated by an actuator 9 (shown in FIG. 2), allowing the position of the molding blade 70 to be accurately controlled.

The amount of slurry 2 in the casting box 10 is at a predetermined level, which is preferably maintained substantially constant, so that the pressure generated by the column of slurry 2 remains substantially constant. In order to maintain the amount of slurry 2 at substantially the same level, the pumps (a first pump and a second pump in the first embodiment of the injection molding machine 100, or a first pump, a second pump and a third pump in the second embodiment of the injection molding machine 101, or a first pump, a second pump and a fourth pump in the third embodiment of the injection molding unit 102) controls the flow of slurry 2 entering the injection molding box 10.

The movable support 20 includes, for example, a continuous stainless steel belt containing a drum assembly. The drum assembly includes a main drum 41, which is located under the injection box 10 and moves the movable support 20. Preferably, the injection box 10 is mounted on the main drum 41.

The slurry 2 is cast onto the steel belt 20 on the drum 41 by means of a casting blade 70, resulting in the formation of a continuous sheet 1 of homogenized tobacco material. In order for the suspension 2 to reach the casting blade 70 and, accordingly, the movable support 20, the casting box 10 has an opening or hole 17 in the area of its bottom, and this hole 17 runs along the width of the casting box 10. The hole 17 is located above the drum 41 near it .

As a result of the forward movement of the steel belt 20, the suspension 2 moves towards the casting blade 70 at the front outlet 18 of the casting box 10 (on the second wall 14, see curve 13 showing the movement of the suspension). The casting blade 70 casts part of the suspension 2 onto the steel belt 20, while the remaining main part of the suspension 2 is returned and recirculated inside the casting box 10. The steel belt 20 moves along the direction of casting (see arrow 44).

There is a gap between the casting blade 70 and the steel strip 20, the dimensions of which determine, among other things, the thickness of the cast sheet 1 of homogenized tobacco material.

The injection molding machine 100 operates according to the method of the present invention.

The viscosity of the suspension 2 is assessed. The viscosity is preferably assessed using a viscometer 60 located in the first reservoir 3, or in the casting box 10, or in the first flow path 4 and/or in the second flow path 5. More than one viscometers can be used. Alternatively, the viscosity of the suspension can be calculated based on the composition of the suspension.

The first flow path 4 and the second flow path 5 are equipped with two different pumps 6, 7, which are suitable for different types of suspension viscosity. For example, the first pump 6 is preferably used for a "low viscosity slurry" and the second pump 7 is preferably used for a "high viscosity slurry". Thus, depending on whether the viscosity of the suspension is above or below a predetermined threshold value, the control element 50 accordingly opens the valve 23 and leaves the valve 21 closed, or vice versa, so that the suspension flows from the first reservoir to the injection molding machine along the second path 5 flow or along the first flow path 4 under the action of the second pump 7 or the first pump 6. Thus, the suspension uses only one of the two flow paths at any time.

In the casting box 10, the suspension 2 is preferably maintained at the same level. In addition, in the casting box, the flow rate of the suspension entering from the first flow path 4 or the second flow path 5 is monitored using a sensor 80. The casting box 10 casts the suspension 2 onto a movable support 20, which moves along the casting direction 44, by means of a casting blade 70 .

Preferably, the viscosity of the suspension is continuously monitored during casting. Therefore, if the viscosity of the slurry changes or the measured flow rate falls outside a predetermined range, then the control element 50 can actuate the valves 21 and 23, changing the flow path used by the slurry to reach the casting box 10.

The following will briefly describe the method of operation of the injection molding machines 101, 102, only mentioning differences from the method of operation of the injection molding machine 100.

The injection molding apparatus 102 operates in the same manner as the injection molding apparatus 100, however, it has three different flow paths 4, 5, 34 that can be selected on an alternative basis. There are three different pumps 6, 7, 35, each of which is preferably used for a different set of viscosities of the slurry 2. For example, the first pump 6 is preferably used for a "low viscosity slurry", the second pump 7 is preferably used for a "high viscosity slurry", and the fourth pump 35 is used for "intermediate viscosity slurry" that is in the viscosity range between a high viscosity slurry and a low viscosity slurry. Thus, if the viscosity of the slurry is above the first threshold value and below the second threshold value, then the control element 50 opens the valve 36 and leaves the valves 21 and 23 closed so that the slurry flows from the first reservoir to the injection molding unit along the fourth flow path 34 under the action of the fourth pump 35. If the viscosity of the suspension is above the second threshold value, then the control element 50 opens the valve 23 and leaves the valves 21 and 36 closed so that the suspension flows from the first reservoir to the injection molding unit along the second flow path 5 under the action of the second pump 7. If the viscosity of the suspension is lower first threshold value, then the control element 50 opens the valve 21 and leaves the valves 23 and 36 closed, so that the suspension flows from the first reservoir into the injection molding unit along the first flow path 4 under the action of the first pump 6. Thus, only one of the three is used in the suspension flow paths at any given time. Therefore, after evaluating the viscosity of the slurry, one of the first flow path 4, the second flow path 5, or the fourth flow path 34 is selected to direct the slurry from the first reservoir 3 to the casting box 10, where it is cast as in the casting machine 100. To transfer the slurry from tank to casting box uses one flow path.

In the injection molding unit 101, the slurry is placed in two reservoirs, namely a first reservoir 3 and a second reservoir 30. The first reservoir 3 is connected to the injection box 10 through a first flow path 4 and a second flow path 5 having a first pump 6 and a second pump 7, respectively. The second reservoir 30 is connected to the injection box through a third flow path 11 and a second flow path 5 having a third pump and a second pump, respectively. Preferably, the first pump 6 and the third pump 9 are suitable for use over the same range of slurry viscosities, while the second pump 5 in the second flow path is suitable for use over a different range of slurry viscosities, for example at higher viscosities than in the case of the first pump and the third pump. Thus, depending on whether the viscosity of the suspension is above or below a predetermined threshold value, the control element 50 opens the valves 21, 31 and leaves the valves 23 and 33 closed, or vice versa, respectively, so that the suspension 2 flows from the first reservoir 3 and the second reservoir 30 into the injection molding box 10 along the first flow path 4 and the third flow path 11 under the action of the first pump 5 and the third pump 9, or the suspension 2 flows from the first reservoir 3 and the second reservoir 30 into the injection molding box 10 along the second flow path 5 under the influence of the second pump 7. Thus, the slurry is able to flow from the two reservoirs into the casting box 10 along one flow path, that is, the second flow path 5, or simultaneously through two different flow paths, namely the first flow path 4 and the third flow path 11.

Claims (15)

1. A method of casting a sheet of an alkaloid-containing material, comprising: producing a suspension of an alkaloid-containing material, the suspension being characterized by a viscosity value; storing the suspension in the first reservoir; providing a first flow path and a second flow path for fluid communication between the first reservoir and the injection molding box, the first flow path comprising a first pump and the second flow path comprising a second pump; directing the slurry along a first flow path or a second flow path from the first reservoir to the casting box to create a slurry flow along the first flow path or a second flow path based on the viscosity value of the slurry; and casting the slurry to form a sheet of the alkaloid-containing material. 2. The method of claim 1, wherein the step of directing the slurry along the first flow path or the second flow path from the first reservoir to the casting box based on a viscosity value of the slurry includes: setting a threshold viscosity value; directing the suspension along the first flow path if the viscosity value of the suspension is below a threshold viscosity value; directing the suspension along the second flow path otherwise. 3. The method according to claim 1 or 2, in which the suspension is characterized by its composition and which includes one or more of the following: measuring the viscosity value of the suspension in the first reservoir; measuring the viscosity value of the suspension in the casting box; measuring a viscosity value of the suspension in the first flow path or the second flow path; determination of the viscosity value based on the composition of the suspension. 4. The method of claim 3, comprising measuring or determining a viscosity value of the suspension more than once and switching the flow of the suspension from the first flow path to the second flow path or vice versa if the viscosity value changes from the previous measurement or determination result. 5. The method according to one of the previous paragraphs, including: storing the suspension in a second tank; providing a third flow path for fluid communication between the second reservoir and the injection molding box, the third flow path comprising a third pump; connecting the second flow path to the second reservoir such that the second reservoir and the injection molding box are in fluid communication via the second flow path; and directing the slurry along either a third flow path or a second flow path from the second reservoir to the casting box based on the viscosity value of the slurry. 6. The method according to claim 5, including: more than a single measurement or determination of the viscosity value of the suspension; switching both slurry streams from the first flow path and the third flow path to the second flow path, or vice versa, in the event of a change in the viscosity value compared to the result of a previous measurement or determination. 7. The method of claim 4 or 6, wherein the flow of slurry entering the casting box sets the flow rate, and which includes maintaining the flow rate of the slurry entering the casting box at a constant level before and after switching. 8. The method as claimed in one of the preceding claims, wherein the first pump has a speed of the first pump and the second pump has a speed of the second pump, the method comprising: measuring the speed of the first pump or the speed of the second pump; measuring the flow rate of the suspension in the first flow path or in the second flow path; switching the slurry flow from the first flow path to the second flow path, or vice versa, if the measured slurry flow rate in the first flow path or in the second flow path is outside a predetermined range for the corresponding measured speed of the first pump or the speed of the second pump. 9. The method of any one of the preceding claims, wherein the first pump has a speed of the first pump and the second pump has a speed of the second pump, the method comprising: measuring the flow rate of a slurry exiting the casting box or entering the casting box or being in the first flow path, or in the second flow path; and changing the speed of the first pump or the speed of the second pump based on the measured flow rate of the slurry. 10. An injection molding machine for producing sheets of alkaloid-containing material, comprising: a first reservoir for storing a suspension of alkaloid-containing material; a casting box containing a casting device for casting a sheet of alkaloid-containing material; a viscosity evaluation unit for measuring or determining the viscosity value of the suspension; a first flow path fluidly connecting the first reservoir and the casting box for directing the flow of slurry into the casting box; a second flow path fluidly connecting the first reservoir and the casting box to direct the flow of slurry into the casting box; a first pump and a second pump, wherein the first pump is located within the first flow path and the second pump is located within the second flow path; a first valve for selectively opening either the first flow path or the second flow path to allow slurry to flow from the first reservoir into the casting box along the first flow path or the second flow path; and a control element for controlling the first valve to select either the first flow path or the second flow path based on the viscosity value of the suspension. 11. The installation of claim 10, wherein the first pump or the second pump is a positive displacement pump. 12. The apparatus of claim 10 or 11, wherein the first flow path or the second flow path comprises a conduit having a diameter of from about 2.5 centimeters to about 10.5 centimeters. 13. Installation according to one of claims 10-12, in which the viscosity assessment unit contains a viscometer. 14. Installation according to one of paragraphs 10-13, including: a second tank; a third flow path fluidly connecting the second reservoir to the casting box for directing the flow of slurry into the casting box; a third pump located within the third flow path; wherein the second flow path fluidly connects the second reservoir and the casting box to direct the flow of slurry into the casting box; a second valve for selectively opening either the third flow path or the second flow path to allow slurry to flow from the second reservoir into the casting box along either the third flow path or the second flow path; wherein the control element controls the second valve to select the third flow path or the second flow path based on the viscosity value of the suspension. 15. The installation according to one of claims 10 to 14, wherein the first pump, the second pump or the third pump has the speed of the first pump, the speed of the second pump or the speed of the third pump, and the installation includes a speed controller for changing the speed of the first pump or the speed of the second pump , or the speed of the third pump.