Method and machine for making a semifinished, continuous layer

Abstract

A method for making a semifinished, continuous layer, comprising a step of mixing a first quantity of liquid with a second quantity of dry product in a kneader (100), obtaining a mixture having a moisture content of less than 65%, and a subsequent step of forming a first layer (S1) apart from the mixture. The method provides fragmenting the first layer (S1) into a plurality of fragments having finished dimensions and performing a second lamination of the fragments so as to obtain a second continuous layer (S2).

Description

[0001] DESCRIPTION METHOD AND MACHINE FOR MAKING A SEMIFINISHED, CONTINUOUS LAYER.

[0002] Technical field

[0003] The present invention relates to the field of smoking articles and the object thereof is a method and a machine for making a semifinished, continuous layer.

[0004] Background art

[0005] It is known to make a reconstituted continuous web from a plant-based mixture. The term "plant-based” mixture means a plant-based material (tobacco or non-tobacco) processed by grinding or other similar procedure to modify the particle size thereof so as to promote subsequent mixing treatments thereof. In particular, it is intended that the continuous web is a semifinished product obtained by mixing and processing at least one dry plant component, such as tobacco or non-tobacco (cellulose or cellulose derivatives, rapeseed, hemp, straw or other varieties, hemp, aromatic leaves or others) with a wet component, such as, e.g. water, and one or more additives, according to the generality of the invention.

[0006] In particular, methods are known for making “dough” type mixtures, i.e., with a low percentage of moisture content, which are characterized by the preparation of a mixture obtained from mixing particles of tobacco and / or cellulose with at least one liquid component, such as, e.g. water, where the mixture is portioned into predetermined doses followed by subjecting it to a succession of separate laminating steps to obtain the continuous layer of reconstituted material which is finally dried, obtaining a continuous web. In particular, the lamination is carried out primarily by means of at least one vertical laminating stage, followed by at least one horizontal laminating stage.

[0007] Although this technology is well operable for the mentioned type of mixtures, the Applicant has noted that this technology is not completely optimized due to the specific physical-mechanical properties of such a type of mixture (such as, for example, viscosity, elasticity, density, tenacity, expandability, adhesiveness, colloidality, and others) which make the handling thereof complex.

[0008] In particular, the Applicant has found that for a mixture characterized by the presence of a considerable percentage of tobacco and / or cellulose and a reduced liquid content, a criticality persists in processing the mixture, and in particular, in the horizontal lamination step for the mixture. Indeed, especially in this latter step, the handling of the mixture is critical because the laminating rollers are not capable of effectively processing the mixture itself, compromising the formation of a continuous layer with the desired properties.

[0009] Therefore, in such a context, it is the technical task of the present invention to provide a method for making a semifinished, continuous layer which is free from the drawbacks of the prior art.

[0010] It is therefore the object of the present invention to provide a method for making a semifinished, continuous layer which is capable of obtaining a satisfactory finished product in terms of quality.

[0011] It is a further object of the present invention to provide a method for making a semifinished, continuous layer which is capable of ensuring a correct lamination of the mixture.

[0012] Disclosure of the invention

[0013] Within the scope of the same technical task, it is a further object of the invention to provide a method for making a semifinished, continuous layer which, in order to be implemented on the specific material identified, requires a compact and structurally simplified system.

[0014] The technical task specified and the objects specified are substantially achieved by a method for making a semifinished, continuous layer comprising a step of feeding a first quantity of at least one liquid and a second quantity of at least one dry fibrous, ground and / or powdered product, into a mixing chamber of a kneader. The method provides a step of mixing the second quantity of dry product with the first quantity of liquid in the kneader, obtaining a mixture having a moisture content of less than 65%. The method provides a subsequent step of forming a first layer from the mixture by means of a first laminating unit comprising at least one pair of rollers.

[0015] The first layer can be a substantially continuous layer or can have localized discontinuity. In other words, following the first lamination, the first layer can be homogeneous and without interruptions or it can have holes, openings or have a fragmented part thereof.

[0016] The method provides fragmenting the first layer into a plurality of fragments having finished dimensions and a subsequent lamination of the fragments so as to obtain a second continuous layer by means of a second laminating unit comprising at least one respective pair of rollers. The term “continuous” therefore means that the second layer does not have localized discontinuity, rather is homogeneous and continuous, both on a local level and when considered in its entirety. The second continuous layer can therefore be dried so as to obtain a continuous web. The Applicant has found that performing a step of fragmenting the continuous layer followed by a further lamination of the fragments so as to create a new continuous layer allows various advantages to be obtained. Firstly, this sequence of actions contributes to improving the integration of the ingredients and to ensuring a more uniform distribution of any fillers or additives, providing increased control over the consistency of the mixture. This process contributes therefore to improving the quality of the finished product, ensuring a more homogenous continuous layer and facilitating the processability of the mixture during the subsequent production steps. Moreover, these operations advantageously allow energy efficiency to be optimized and time to be saved in the entire production process. By virtue of the mixing carried out in the second laminating unit, the upstream kneader may require less time and energy to complete the preparation step.

[0017] The method according to the present invention can further provide one or more of the technical aspects outlined below.

[0018] According to an aspect, the step of fragmenting is preferably accomplished by cutting performed by at least one automatic cutting station.

[0019] Preferably, the step of fragmenting comprises a sub-step of making a plurality of parallel, longitudinal cuts along the direction of extension of the first layer.

[0020] Preferably, the step of fragmenting comprises a sub-step of making a plurality of cuts transverse to the direction of extension of the first layer.

[0021] Preferably, the step of fragmenting comprises both sub-steps of longitudinal cutting and transverse cutting. However, according to alternative embodiments, the step of fragmenting the first layer can provide only one between the sub-step of longitudinal cutting and the substep of transverse cutting.

[0022] According to a first example, the sub-step of making transverse cuts is carried out after the sub-step of making longitudinal cuts.

[0023] According to a second example, the sub-step of making longitudinal cuts is carried out after the sub-step of making transverse cuts.

[0024] According to a further example, the sub-step of making longitudinal cuts is carried out simultaneously to the sub-step of making transverse cuts.

[0025] According to an aspect, at least in the step of fragmenting, the first layer is supported by a conveyor, in particular, a belt or mesh conveyor. Preferably, the conveyor receives the continuous layer leaving the first laminating unit and releases the plurality of fragments into the second laminating unit.

[0026] Preferably, independently of how the step of fragmenting is performed, the fragments have a regular shape, in particular square or rectangular.

[0027] Preferably, the fragments have a thickness comprised between 0.2 mm and 4 mm. Preferably, the fragments have a surface comprised between 0.5 mm and 2 mm.

[0028] Preferably, the fragments have a length comprised between 30 and 100 mm and / or a width comprised between 15 and 60 mm.

[0029] According to an aspect, the first lamination is a vertical lamination.

[0030] According to a particularly advantageous embodiment, the first lamination is a multistage, vertical lamination where each stage comprises a respective pair of rollers.

[0031] Alternatively, the first lamination is a single-stage, vertical lamination.

[0032] According to an aspect, independently of how the first lamination is carried out, the second lamination can be a horizontal lamination or a vertical lamination.

[0033] Preferably, the second lamination is a horizontal lamination when it defines the last laminating stage (for example, before the drying).

[0034] Preferably, the second lamination is a vertical lamination when it defines an intermediate laminating stage (followed by at least one further laminating step).

[0035] The second lamination, which is preferably a multistage lamination, performs, in at least a first lamination stage comprising a pair of opposite rollers, a step of mixing the plurality of fragments in an accumulation niche defined between the two opposite rollers, followed by a step of compressing the plurality of fragments in the through slot between the two rollers so as to make the second continuous layer.

[0036] According to an alternative embodiment, the second lamination is a single- stage lamination.

[0037] According to an embodiment, the method provides the second continuous layer leaving the second lamination to be sent (directly, i.e., without further laminations) to a drying unit to obtain a continuous web.

[0038] Alternatively, the method provides the second layer to be subjected to a second step of fragmenting, followed by a subsequent third lamination, obtaining a third continuous layer. According to this last embodiment, the method provides a second step of fragmenting the continuous layer to be carried out after the second lamination so as to fragment the second continuous layer into a plurality of fragments having finished dimensions. Subsequently, the method provides a subsequent third step of laminating performed on the plurality of fragments by means of a third laminating unit comprising at least one respective pair of rollers to obtain a third continuous layer.

[0039] The third continuous layer can be sent to the drying unit to obtain the aforesaid continuous web.

[0040] Alternatively, it is possible to provide one or more further fragmentinglaminating cycles downstream of the third lamination.

[0041] Preferably, the third lamination is a horizontal lamination when it defines the last laminating stage (for example, before drying).

[0042] Preferably, the third lamination is a vertical lamination when it defines an intermediate laminating stage (followed by at least one further fragmenting and laminating stage).

[0043] The technical task specified and the objects specified are further substantially achieved by a machine for making a semifinished, continuous layer, in particular suitable for carrying out the method as indicated above. The machine comprises a kneader comprising a containing frame internally defining a mixing chamber and comprising a motor-driven kneading shaft. Such a kneader is preferably configured to operate “in batches”, i.e., by means of discontinuous process with mixing steps alternating to unloading steps for the mixture, followed by loading new dry and liquid components.

[0044] The machine comprises a first feed line configured to feed one or more liquids to the mixing chamber.

[0045] The machine comprises a second feed line configured to feed a dry, ground and / or powder product to the mixing chamber.

[0046] The aforesaid motor-driven kneading shaft is configured to mix the at least one dry, ground and / or powder product and said one or more liquids, obtaining a mixture.

[0047] The machine comprises a first laminating unit, disposed downstream of the kneader, along the processing path, comprising at least one pair of laminating rollers and configured to perform a step of laminating the mixture to obtain a first layer.

[0048] The machine comprises a fragmenting unit, disposed downstream of the first laminating unit, along the processing path and configured to fragment the first layer to obtain a plurality of fragments having finished dimensions.

[0049] The machine comprises a second laminating unit, disposed downstream of the fragmenting unit, comprising at least one pair of laminating rollers and configured to perform a step of laminating the plurality of fragments to obtain a second continuous layer.

[0050] The machine may then comprise a drying unit configured to dry the second continuous layer, obtaining a continuous web.

[0051] Preferably, the fragmenting unit comprises at least one automatic cutting station configured to fragment the first layer by cutting.

[0052] Preferably, the fragmenting unit comprises an automatic, longitudinal cutting station configured to make a plurality of longitudinal, preferably parallel, and more preferably equidistant, longitudinal cuts.

[0053] Preferably, the automatic, longitudinal cutting station comprises a roller provided with a succession of coaxial cutting blades.

[0054] Preferably, the cutting blades are mutually spaced apart by a spacing comprised between 15 mm and 60 mm.

[0055] According to a first embodiment, the spacing between subsequent blades is constant.

[0056] According to a second embodiment, the spacing between subsequent blades is not constant.

[0057] Preferably, the cutting blades have a continuous outer profile.

[0058] Preferably, the cutting blades have an outer profile lying on a plane so as to make straight cuts.

[0059] Alternatively, the cutting blades can have a wavy, irregular outer profile, or in any case, not lying on a plane so as to make non-straight cuts.

[0060] Preferably, independently of the presence of the automatic, longitudinal cutting station, the fragmenting unit comprises an automatic, transverse cutting station configured to make a succession of transverse cuts.

[0061] Preferably, the automatic, transverse cutting station comprises at least one transverse blade, oriented transversely to the direction of extension of the first layer and configured to make a cut at regular intervals on the continuous layer.

[0062] Preferably, the transverse blade has a length equal to or greater than the width of said first layer so as to make the transverse cut of the entire continuous layer with a single cutting operation.

[0063] Preferably, the automatic, transverse cutting station makes a knife cut along a direction transverse to the lying plane of the first layer.

[0064] Alternatively, the automatic, transverse cutting station makes a rotary cut, in particular, by mounting the transverse blade on a support member (roller) rotatable around an axis parallel to the lying plane of the first layer and preferably fixed.

[0065] Preferably, the cutting unit comprises both automatic, longitudinal and transverse cutting stations.

[0066] According to an embodiment, the automatic, transverse cutting station is disposed downstream of the automatic, longitudinal cutting station.

[0067] According to a variant, the automatic, longitudinal cutting station is disposed downstream of the automatic, transverse cutting station.

[0068] According to a further variant, the cutting unit comprises a single station configured to simultaneously make a longitudinal cut and a transverse cut of the first layer.

[0069] According to an aspect, the machine comprises a conveyor configured to support the first layer by means of the fragmenting unit.

[0070] Preferably, the conveyor is configured and / or further disposed to receive the continuous layer leaving the first laminating unit and / or to release the plurality of fragments into the second laminating unit. According to an aspect, the first laminating unit is a vertical laminating unit comprising at least one vertical laminating stage.

[0071] According to a particularly advantageous embodiment, the first laminating unit comprises a plurality of subsequent vertical lamination stages, where each stage comprises a respective pair of rollers.

[0072] According to a variant, the first laminating unit is a horizontal laminating unit.

[0073] According to an aspect, independently of the structure of the first laminating unit, the second laminating unit is a horizontal laminating unit, comprising at least one horizontal laminating stage comprising a respective pair of opposite rollers configured to perform, in at least a first stage of the horizontal laminating unit, a mixing of the plurality of fragments in an accumulation niche defined between the two rollers, and a subsequent step of compressing the plurality of fragments in the through slot between the two rollers so as to make the second continuous layer.

[0074] Preferably, the second laminating unit has a plurality of horizontal laminating stages disposed in succession and each comprising a respective pair of rollers.

[0075] Alternatively, the second laminating unit is a vertical laminating unit comprising at least one vertical laminating stage comprising a respective pair of opposite rollers configured to perform, in at least a first stage of the vertical laminating unit, a step of mixing the plurality of fragments in an accumulation niche defined between the two rollers, and a subsequent step of compressing the plurality of fragments in the through slot between the two rollers so as to make said continuous web.

[0076] According to alternative embodiments, the second lamination is a single- stage, horizontal or vertical, lamination.

[0077] According to an embodiment, the machine comprises a drying unit directly downstream of the second laminating unit.

[0078] According to an embodiment variant, the machine comprises, directly downstream of the second laminating unit, a second fragmenting unit, followed by a third laminating unit.

[0079] The third laminating unit can be followed directly by the drying unit or by a third fragmenting unit, followed by a fourth laminating unit.

[0080] Preferably, the second fragmenting unit has structural and functional features that are completely similar to the preceding fragmenting unit.

[0081] Preferably, the third laminating unit is a horizontal laminating unit when it defines the last laminating stage, in particular before the drying unit.

[0082] Preferably, the third laminating unit is a vertical laminating unit when it defines an intermediate laminating stage (which follows at least a further fragmenting and laminating stage).

[0083] Preferably, the fragmenting units operate by cutting the respective continuous layer while keeping it lying in a substantially horizontal position, in particular, supported by a conveyor or belt having a substantially horizontal lying position.

[0084] Further features and advantages of the present invention will become more apparent from the following indicative and thus non-limiting description of one embodiment of a method for making a web according to the invention.

[0085] Brief description of drawings

[0086] This description will be presented below with reference to the accompanying drawings, provided by way of mere and thus non-limiting indication, in which:

[0087] - Figure 1 shows a diagrammatic view of a system of a preferred exemplary, and therefore non-limiting, embodiment of a machine for making a continuous web according to the present invention;

[0088] - Figure 2 shows a first operating portion of the machine in Figure 1 ;

[0089] - Figure 3 shows a second operating portion of the machine in Figure 1 ;

[0090] - Figure 4 shows a diagrammatic view of a system of a second embodiment of a machine for making a continuous web according to the present invention. Detailed description of preferred embodiments of the invention

[0091] The method for making a continuous layer is now described in one embodiment thereof, with reference to machine 1 used to implement it.

[0092] The web “N” according to the present invention is a plant-based material web. In the present description, the term "plant-based material” means a plant-based material (tobacco or non-tobacco) processed by grinding, or other similar procedure, to modify the particle size thereof so as to promote subsequent mixing treatments thereof. In particular, it is intended that the continuous web is a semi-finished product obtained by mixing and processing at least one dry plant component, such as tobacco or nontobacco (rapeseed, hemp, straw or other varieties, cellulose or cellulose derivatives, hemp, aromatic leaves or others), with a wet component, e.g. water, and one or more additives, according to the generality of the invention.

[0093] According to the present invention, the method provides feeding a first quantity of at least one liquid into a mixing chamber "V" of a kneader 100 and feeding a second quantity of at least one dry fibrous, ground or powdered product, into the mixing chamber "V" of kneader 100.

[0094] The kneader 100 can be of any type, as long as it is capable of mixing the solid and liquid components. Structurally, the kneader 100 comprises a containing frame internally defining a mixing chamber “V” and comprises a motor-driven kneading shaft. Preferably, the kneader 100 is configured to operate “in batches”. Preferably, the kneader 100 is of the horizontal type, i.e., it has a mainly horizontal configuration and extension.

[0095] Preferably, the kneader 100 is configured to operate on mixtures having an overall weight comprised between 4 kg and 450 kg, more preferably comprised between 8 kg and 400 kg (end limits obtained by calculating the ranges from an hourly industrial production and from the cycle times).

[0096] As for feeding the first quantity, the term "at least one liquid" means mainly water and preferably at least one additional component, preferably premixed with water. In particular, the additional component comprises one or more of glycerin, nicotine, lactic acid, propylene glycol, dyes, at least one binding agent.

[0097] In order to feed the first quantity of at least one liquid, the machine 1 comprises a feed line 110 for the at least one liquid, connected to kneader 100.

[0098] If one or more of the aforementioned additional components are included, the first feed line 110 can comprise a plurality of feed branches 111 , 112, each one dedicated to a particular liquid component.

[0099] The first feed line 110 can further comprise an intermediate tank 113, operatively disposed upstream of kneader 100 and connected to kneader 100 by means of a delivery branch 114. The water and additional components are pre-loaded into and pre-dosed in the intermediate tank 113. Preferably, the intermediate tank 113 is provided with mixing means configured to mix the water with the one or more additional components.

[0100] As for feeding the second quantity, the term "at least one dry product" is intended to mean mainly tobacco (in the forms envisaged) and possibly at least one additional dry e.g., fibrous, ground and / or powdered product, preferably in smaller quantities. In particular, the additional dry product can comprise cellulose or cellulose derivatives, rapeseed, hemp, straw or other varieties, hemp, cocoa, aromatic leaves or others.

[0101] According to an alternative, as for feeding the second quantity, the term "at least one dry product" is intended to mean mainly cellulose (in the forms envisaged) and possibly at least one additional dry e.g., fibrous, ground and / or powdered product, preferably in smaller quantities. In particular, the additional dry product can comprise tobacco or derivatives, rapeseed, hemp, straw or other varieties, hemp, cocoa, aromatic leaves or others.

[0102] According to an embodiment, as mentioned above, the at least one dry product can be tobacco-based, i.e., the mixture can comprise a tobacco content higher than 50% by weight, preferably comprised between 50% and 85%, preferably comprised between 55% and 80%. According to this embodiment, the mixture can comprise a cellulose content in fibrous and / or ground or powder form comprised between 0% and 15%, even more preferably between 2% and 8%.

[0103] According to an embodiment, as mentioned above, the at least one dry product can be cellulose-based. In this case, the mixture can comprise a cellulose content higher than 40%, for example, comprised between 50% and 85%, preferably comprised between 50% and 80%, even more preferably comprised between 50% and 60%.

[0104] According to an example, the at least one dry product comprises a cellulose content, preferably cellulose in fibrous and / or ground or powder form. Preferably, the quantity of cellulose can be comprised between 20% and 80% of the mixture, even more preferably between 30% and 70% of the mixture, even more preferably between 50 and 60% of the mixture.

[0105] In order to feed the second quantity of at least one dry product, the system 1 comprises a second feed line 120 for the at least one dry product, which is connected to kneader 100.

[0106] If one or more additional dry products are included, the second feed line 120 can comprise a plurality of feed branches 121 , 122, each one dedicated to a specific dry product.

[0107] Alternatively, in the event of two or more dry products, they can be premixed outside kneader 100 and then be fed to it by means of the same feed branch 121 , 122.

[0108] The second feed line 120 can further comprise an intermediate tank 123, operatively disposed upstream of kneader 100 and connected to kneader 100 by means of a delivery branch 124, where the dry products are pre- loaded and pre-dosed.

[0109] The method thus includes a step of mixing the second quantity of dry product with the first quantity of liquid in the kneader 100, obtaining a mixture with humidity content lower than 65%.

[0110] In particular, the mixture obtained has a moisture content (by weight) comprised between 15% and 50%, preferably between 20% and 35%.

[0111] It is clear that the second quantity of a dry product and the first quantity of a liquid product can be fed into the kneader 100 in any order.

[0112] It is clear that the second quantity of dry product and the first quantity of a liquid can be fed into the kneader 100 simultaneously, possibly after premixing the second quantity of dry product outside the kneader 100. Preferably, the mixture has a quantity of glycerin (by weight) between 2% and 40%.

[0113] In the case where the at least one dry product is a tobacco-based product, as mentioned above, the quantity of glycerin in the mixture can be comprised between 2% and 25%, and preferably it is comprised between 15% and 20%.

[0114] In the case where the at least one dry product is a cellulose-based product, as mentioned above, the quantity of glycerin present in the mixture preferably is comprised between 30% and 40%.

[0115] Once the step of mixing is complete, the mixture is unloaded from the kneader, preferably all at once, and the method provides performing a first lamination of the mixture so as to obtain a first layer “S1 ”. Preferably, but not exclusively, the first layer “S1 ” is continuous. The first lamination is carried out by means of a first laminating unit 2, which comprises at least one pair of laminating rollers 201 , 202, 301 , 302.

[0116] Preferably, the first lamination is a vertical lamination.

[0117] According to an embodiment, the first lamination is a multistage, vertical lamination 200, 300 where each stage comprises a respective pair of rollers 201 , 202, 301 , 302.

[0118] In an alternative embodiment, the first lamination is a single-stage lamination; in particular it comprises a single pair of rollers.

[0119] The step of forming the first layer “S1 ” firstly provides performing at least one vertical lamination of the mixture by means of a vertical laminating unit 2 provided with at least one pair of rollers 201 , 202, 301 , 302, obtaining the first layer “S1”, which is released preferably onto a conveyor 4, preferably a belt or mesh conveyor, configured to convey the laminated semifinished product leaving the vertical laminating unit 2 at least through a fragmenting unit 10 and preferably, into a second laminating unit 3, as better explained in the continuation of the present description.

[0120] Structurally, the first laminating unit 2 comprises at least a first vertical laminating stage 200 comprising a respective pair of laminating rollers 201 , 202.

[0121] Preferably, the first laminating unit 2 further one or more subsequent vertical laminating stages 300, where each vertical laminating stage 200, 300 comprises a respective pair of laminating rollers 201 , 202, 301 , 302.

[0122] In such embodiments, the laminated mixture from the first vertical laminating stage 200 is fed by gravity or by transport to the subsequent vertical laminating stages 300. One or more scraping tools 400, such as, for example blades, can also be provided, operatively connected to the rollers of each vertical laminating stage 200, 300, which are configured to carry out the aforesaid scraping.

[0123] According to a particularly advantageous embodiment, the first laminating unit 2 comprises a first vertical laminating stage 200 and a second vertical laminating station 300. However, according to the generality of the invention, as will be increasingly apparent from the continuation of the present invention, three or more vertical laminating stages may also be employed.

[0124] Independently of the number of laminating stages employed, the aforesaid first layer “S1 ” is obtained leaving the first laminating unit 2.

[0125] According to particular applications, for example, when the mixture dispensed by the kneader has a particularly granular structure, flakes with planar positioning may be produced exiting the first vertical laminating stage, due to a particular property of the mixture which reduces its ability to form a continuous layer. Such flakes can then be collected by gravity in a niche formed by a subsequent vertical laminating stage which carries out a subsequent lamination thereof, forming the mentioned first layer “S1 ”. At this point, the method provides a step of fragmenting the first layer “S1 ” into a plurality of fragments “F” with finished dimensions.

[0126] To this end, machine 1 comprises the fragmenting unit 10, disposed downstream of the first laminating unit 2 along the processing path “L”. The fragmenting unit 10 is configured to fragment the first layer “S1 ” to obtain a plurality of fragments “F” having finished dimensions.

[0127] In the context of the present invention, the term “fragments with finished dimensions” means that the continuous layer “S1 ” is cut and / or chopped so as to obtain a plurality of “pieces” each having a measurable and substantially small dimension with respect to the dimension of the first layer “S1”.

[0128] According to an aspect, the fragments “F” have a regular shape, in particular, square or rectangular.

[0129] Preferably, the fragments “F” have a thickness comprised between 0.2 mm and 4 mm.

[0130] Preferably, the fragments “F” have a surface comprised between 0.5 mm and 2 mm.

[0131] Preferably, the fragments “F” have a length comprised between 30 and 100 mm and / or a width comprised between 15 and 60 mm.

[0132] According to a particularly advantageous embodiment, the step of fragmenting is accomplished by cutting performed by at least one automatic cutting station 11 , 15. To this end, the fragmenting unit 10 comprises at least one automatic cutting station 11 , 15 configured to fragment the first layer “S1 ” by cutting, as clarified in the continuation of the present description. A preferred embodiment of the fragmenting unit 10 is disclosed by way of example in Figure 2.

[0133] Preferably, the step of fragmenting comprises a sub-step of making a plurality of parallel, longitudinal cuts along the direction of extension of the first layer “S1 ”.

[0134] The fragmenting unit 10 comprises an automatic, longitudinal cutting station 11 configured to make a plurality of longitudinal cuts. Preferably, the automatic, longitudinal cutting station 11 comprises a roller 12 provided with a succession of coaxial cutting blades 13. In particular, the cutting blades 13 are spaced apart from one another by a spacing comprised between 15 mm and 60 mm. Preferably, the spacing is constant. Preferably, the automatic, longitudinal cutting station 11 comprises a scraping tool 14 associated with roller 12.

[0135] Once this sub-step is complete, longitudinal portions are obtained which are defined by longitudinal strips of the first layer “S1 ”.

[0136] Such longitudinal portions have a width comprised between 30 mm and 100 mm. The term “width” means a dimension of extension of the longitudinal portions in relation to the feeding direction of the longitudinal portions along the processing path “L”. The width is indeed the transverse extension of the longitudinal portions with respect to the feeding direction of the longitudinal portions along the processing path “L”.

[0137] Preferably, the step of fragmenting comprises a sub-step of making a plurality of cuts transverse to the direction of extension of the first layer “S1 ”. To this end, the fragmenting unit 10 comprises an automatic, transverse cutting station 15 configured to make a succession of transverse cuts. According to an embodiment of the method, the sub-step of making a plurality of transverse cuts is carried out after the sub-step of making a plurality of longitudinal cuts. The automatic, transverse cutting station 15 is therefore disposed downstream of the automatic, longitudinal cutting station 11 . The automatic, longitudinal cutting station 11 and the automatic, transverse cutting station 15 are both disposed upstream of the second laminating unit 3. Thus, the sub-step of making the plurality of transverse cuts and the sub-step of making the plurality of longitudinal cuts are both carried out before the second lamination.

[0138] According to other variants, the sub-step of making a plurality of transverse cuts and the sub-step of making a plurality of longitudinal cuts can occur simultaneously.

[0139] The automatic, transverse cutting station 15 comprises at least one transverse blade oriented transversely to the direction of extension of the first layer “S1 ” and configured to make a cut at regular intervals on the first layer “S1 ”. In other words, the transverse blade is directed transversely to the feeding direction of the longitudinal portions along the processing path “L”. Preferably, the transverse blade has a length greater than or equal to the width of the first layer “S1 ”. Preferably, the transverse blade is associated with a connecting rod-crank mechanism.

[0140] According to an aspect, during the entire fragmenting step, the first layer “S1” is supported by the aforesaid conveyor 4. In other words, the conveyor 4 is configured to support the first layer “S1 ” through the fragmenting unit 10.

[0141] Moreover, preferably, the conveyor 4 is configured and / or disposed to receive the continuous layer “S1 ” exiting the first laminating unit 2 and / or to release the plurality of fragments “F” entering the second laminating unit 4.

[0142] Once the sub-step of transverse cutting is complete, the aforesaid fragments “F” having finished dimensions are obtained, which are subjected to a second lamination by means of the aforesaid second laminating unit 3 comprising at least one respective pair of rollers 501 , 502 in order to obtain a second continuous layer “S2”. The second laminating unit 3 is disposed downstream of the fragmenting unit 10 and is configured to perform a lamination of the plurality of fragments “F” so as to obtain the second continuous layer “S2”.

[0143] Advantageously, the second lamination allows a second continuous layer “S2” to be obtained both at a local level and taken in its entirety. In other words, the second continuous layer “S2” does not have local discontinuities (such as holes, openings or fragmented portions) and extends along the length thereof in a continuous manner.

[0144] According to a particularly advantageous embodiment, the second lamination 3 is a horizontal-type lamination, preferably multistage.

[0145] As visible in Figure 3, the second laminating unit 3 comprises at least one horizontal laminating stage 500 provided with a respective pair of rollers 501 , 502. Preferably, the second laminating unit 3 is a multistage laminating unit having two or more stages 500, each comprising a respective pair of rollers 501 , 502 configured to achieve a controlled reduction of the thickness of the continuous layer "S2" up to having a calibrated value of thickness. To this end, the second laminating unit 3 comprises a plurality of pairs of horizontal rollers 501 , 502 arranged in series, which pairs of rollers 501 , 502 delimit an increasingly narrow passage therebetween to gradually reduce the thickness of the continuous web "S2".

[0146] According to an aspect of the present invention, as shown in Figure 3, the second laminating unit 3 comprises at least one horizontal laminating stage 500 comprising a respective pair of opposite rollers 501 , 502 configured to mix or homogeneously redistribute the plurality of fragments “F” in a niche 503 defined between the two rollers 501 , 502, followed by a step of compressing the plurality of fragments “F” in the through slot between the two rollers 501 , 502, so as to obtain the continuous layer “S2”. Preferably, each horizontal laminating stage 500 carries out the aforesaid step of mixing the mixture in the respective niche 503.

[0147] In other words, the two opposite rollers 501 , 502 of such an at least one horizontal laminating stage 500 define, immediately upstream thereof, an accumulation niche 503 of the laminated semifinished product which tends to form a mass having the shape of the niche 503 itself, which is deformed, mixed and / or blended with respect to the flow reaching said rollers 501 , 502. The mixture material is then progressively retrieved by the rotation of the rollers 501 , 502, and compressed up to obtaining the mentioned second continuous layer “S2”. The horizontal laminating stage 500 thus performed therefore re-mixes and completes the hydration of the dry particles in the mixture. In other words, a step of accumulating the material in the niche 503 defined between the surfaces of the two rollers 501 , 502 is carried out, and a step of compression applied between the two rollers 501 , 502 to form the continuous layer “S2” at a constant thickness is carried out. With this operation, the mixture material is subjected to a re-mixing step in the accumulation area (niche 503) which, in combination with the subsequent compression between the two rollers 501 , 502 and with the specific liquid content of the material itself, further kneads the laminated semifinished product. Therefore, as the number of laminating stages 500 increases, it is possible to carry out a greater manipulation of the mixture, improving the physical-mechanical properties thereof and the hydration of the dry particles.

[0148] Advantageously, therefore, in addition to forming the continuous layer “S2”, the lamination thus carried out performs a crucial role in mixing the mixture through the accumulation niche 503 at the inlet of the respective opposite rollers 501 , 502. This action contributes to improving the integration of the ingredients, ensuring a more uniform distribution of any fillers or additives, and providing increased control over the consistency of the mixture. This process contributes therefore to improving the quality of the finished product, ensuring a more homogeneous continuous layer “S2” and facilitating the processability of the mixture during the subsequent production steps.

[0149] Moreover, these operations advantageously allow energy efficiency to be optimized and time to be saved in the entire production process. By virtue of the mixing carried out in the second laminating unit 3, the upstream kneader 100 may require less time and energy to complete the preparation step.

[0150] According to an alternative embodiment, shown in Figure 4, the second laminating unit 3 is of the vertical type and comprises at least one first vertical laminating stage 600.

[0151] Preferably, such a second laminating unit 3 is structurally and functionally equivalent or identical to the first laminating unit 2. In particular, the second laminating unit comprises a plurality of vertical laminating stages 600, 700 in succession, where each stage comprises a respective pair of rollers 601 , 602, 701 , 702.

[0152] One or more scraping tools 400, such as blades, can also be included, operatively connected to the rollers of each vertical laminating stage 600, 700, which blades are configured to carry out the aforesaid scraping.

[0153] Functionally, the first pair of rollers 600 is configured to mix the plurality of fragments in an accumulation niche defined between the two rollers 601 , 602, followed by the step of compressing the plurality of fragments in the through slot between the rollers 601 , 602 so as to make the second continuous layer “S2”. Functionally, the mixture laminated by the first vertical laminating stage 600 is fed by gravity to the subsequent vertical laminating stage 700.

[0154] Preferably, the second laminating unit 3 in this embodiment is configured to form the second laminating layer “S2” more accurately with respect to the first laminating unit 2, in particular by means of a more accurate calibration.

[0155] In this embodiment, the machine comprises, downstream of the second laminating unit 3, a second fragmenting unit 20 configured to fragment the second continuous layer “S2” to obtain a plurality of fragments “F” having finished dimensions.

[0156] Preferably, the second fragmenting unit 20 is structurally and functionally equivalent or identical to the preceding (first) fragmenting unit 10. Preferably, therefore, the second fragmenting unit 20 is configured to perform an equivalent fragmenting step as in the aforesaid fragmenting unit 10.

[0157] The fragments “F” produced by the second fragmenting unit 20 may be of identical shape and / or dimensions with respect to the fragments “F” produced by the preceding (first) fragmenting unit 10, or they may be different with respect thereto.

[0158] In this embodiment, the machine comprises a third laminating unit 4, disposed downstream of the second fragmenting unit 20 and comprising at least one pair of laminating rollers 801 , 802 and configured to perform a step of laminating the plurality of fragments “F” so as to obtain a third continuous layer “S3”.

[0159] Preferably, the third laminating unit 4 is a horizontal laminating unit.

[0160] Preferably, the third laminating unit 4 has entirely similar or identical structure and functionality as the second laminating unit 3 described with reference to the first embodiment of machine 1 , shown in Figure 1 .

[0161] In particular, the third laminating unit 4 comprises at least one horizontal laminating stage comprising a respective pair of opposite rollers 801 , 802 configured to mix, in at least a first stage of the horizontal laminating unit, the plurality of fragments “F” in an accumulation niche defined between the two rollers 801 , 802, followed by compressing the plurality of fragments “F” in the through slot between the two rollers 801 , 802 so as to make the third continuous layer “S3”.

[0162] Preferably, the third laminating unit 4 has a plurality of horizontal laminating stages disposed in succession and each comprising a respective pair of rollers 801 , 802 for progressively reducing the thickness of the third continuous layer “S3”.

[0163] Advantageously, such an embodiment allows a further improvement of the uniformity of web “N” to be obtained, as well as an improved hydration and reduction of the dimensions of the solid parts of the mixture.

[0164] According to an embodiment, the horizontal lamination (and correspondingly, the horizontal laminating unit) may be absent, and only the vertical lamination (for example, several vertical lamination stages, as described above) may be present.

[0165] According to a different embodiment (not shown), the first processing unit 2 and / or the second processing unit 3 can comprise a plurality of rollers disposed tangentially to one another to define a laminating and processing path for forming the layer of material. In the case where the second laminating unit 3 is arranged in this way, the so-called fragments obtained can be fed between the first pair of rollers of the laminating and processing path (for example, by feeding from the top, for example, by means of feeding by gravity or transport), and therefore they can transit along the path, obtaining the continuous layer.

[0166] According to the embodiment in which the first processing unit 2 and / or the second processing unit 3 comprise a plurality of rollers disposed tangentially to one another to define a laminating and processing path for forming the layer of material, the step of fragmenting can occur by means of one or more cutting rollers disposed along the laminating and processing path and arranged to carry out the aforesaid step of fragmenting. In particular, the cutting rollers are provided with one or more transverse (i.e., substantially perpendicular to the path of the mixing material and substantially parallel to the rotation axis of the roller itself) and longitudinal (i.e., substantially parallel to the path of the mixing material and substantially perpendicular to the rotation axis of the roller itself) projections (or cutting elements) and are selectively positionable towards and / or away from at least one of the rollers of the laminating and processing path to produce the fragments “F” with the mixing material in transit along the laminating and processing path. According to an example, one cutting roller provided with longitudinal projections and one cutting roller provided with transverse projections disposed in succession to each other can be provided. Alternatively, a single roller provided with longitudinal projections and transverse projections can be provided. The cutting roller and / or rollers therefore constitute an automatic cutting station.

[0167] Once the second continuous layer “S2” or the third continuous layer “S3” is made, the method can then comprise a step of drying to obtain a continuous dried web “N”. To this end, the machine 1 comprises a drying unit 900, of the known type and therefore not described in detail.

[0168] According to a possible embodiment, the at least one dry product comprises metallic particles and / or powders. The metallic particles and / or powders are therefore fed into the kneader 100, for example, by means of the feed line 120 described above. To this end, the feed line 120 can comprise a dedicated feed branch 121 , 122. Alternatively, the metallic particles and / or powders can be premixed outside the kneader 100, for example, with another dry product (e.g. tobacco or cellulose) and be fed into the kneader 100 by means of the same feed branch 121 , 122.

[0169] According to the aforementioned embodiment, the mixture formed comprises a content of said metallic particles and / or powders comprised between 3% and 30% by weight, preferably comprised between 5% and 20%, and more preferably equal to about 8%.

[0170] Advantageously, the formation of the fragments “F” in this embodiment allows an optimal mixing of the metallic powders and / or particles with the remaining part of the mixture. Indeed, when the mixture is being formed by means of a conventional type of lamination, an optimal distribution of such metallic powders and / or particles cannot be ensured. Instead, the formation of fragments “F” containing such metallic powders and / or particles and the subsequent second lamination allows a further mixing stage of the mixture, where the metallic powders and / or particles are better distributed against a laminating process of the prior art.

[0171] It is understood that the metallic particles and / or powders can be provided in addition to another dry product (e.g. tobacco or cellulose).

[0172] The metallic particles and / or powders are provided to promote the thermal conductivity of the end product, which is intended for the sector of smoking articles. It is understood that in this particular embodiment, the mixture does not comprise other conductive particles capable of promoting thermal conductivity apart from the aforementioned metallic particles and / or powders. In other words, the mixture does not comprise other particles such as graphite, carbon and its derivatives and / or minerals capable of promoting thermal conductivity.

[0173] The present invention achieves the preset objects, eliminating the drawbacks of the prior art.

[0174] The step of fragmenting with subsequent lamination allows improving the properties of the material that forms the continuous layer, in particular, an improvement of the homogeneity and uniformity of the material, as well as increased control over the properties (thickness, particle size) of the continuous layer obtained.

Claims

CLAIMS1. A method for making a semifinished, continuous layer, comprising the following steps:- a step of mixing a first quantity of at least one liquid with a second quantity of at least one dry product in a kneader (100) to obtain a mixture, where said mixture has a moisture content of less than 65%;- a subsequent step of performing a first lamination on the mixture by means of a first laminating unit (2) comprising at least one pair of rollers (201 , 202) to obtain a first layer (S1 );- a subsequent step of fragmenting the layer (S1) into a plurality of fragments (F) having finished dimensions;- a step of performing a second lamination on the plurality of fragments (F) by means of a second laminating unit (3) comprising at least one respective pair of rollers (501 , 502) to obtain a second continuous layer (S2).

2. The method according to claim 1 , wherein the step of fragmenting is accomplished by cutting performed by at least one automatic cutting station (11 , 15).

3. The method according to claim 1 or 2, wherein the step of fragmenting comprises a sub-step of making a plurality of parallel, longitudinal cuts along the direction of extension of the first layer (S1).

4. The method according to any one of the preceding claims, wherein the step of fragmenting comprises a sub-step of making a plurality of cuts transverse to the direction of extension of the first layer (S1).

5. The method according to claim 4 when depending on claim 3, wherein the sub-step of making the plurality of transverse cuts and the sub-step of making the plurality of longitudinal cuts are both carried out before the second lamination.

6. The method according to claim 5 or claim 4 when dependent on claim 3, wherein the sub-step of making the transverse cuts is carried out after thesub-step of making the longitudinal cuts.

7. The method according to any one of the preceding claims, wherein the fragments (F) have a regular shape, in particular, square or rectangular.

8. The method according to any one of the preceding claims, wherein the fragments (F) have a thickness comprised between 0.2 mm and 4 mm and / or wherein the fragments (F) have a length comprised between 30 mm and 100 mm and / or a width comprised between 15 mm and 60 mm and / or a surface area comprised between 0.5 and 2 mm.

9. The method according to any one of the preceding claims, wherein the first layer (S1) is supported by a conveyor (4), in particular, a belt conveyor or a mesh conveyor, at least during the step of fragmenting; said conveyor (4) preferably receiving the continuous layer exiting said first laminating unit (2) and releasing said plurality of fragments (F) entering the second laminating unit (3).

10. The method according to any one of the preceding claims, wherein the first lamination is a vertical lamination, preferably a multistage, vertical lamination, where each stage (200, 300) comprises a respective pair of rollers (201 , 202).11 . The method according to any one of the preceding claims, wherein the second lamination is a horizontal lamination, preferably multistage, and performs, in at least a first horizontal lamination stage (500) comprising a pair of opposite rollers (501 , 502), a step of mixing the plurality of fragments (F) in an accumulation niche (503) defined between the two opposite rollers (501 , 502), followed by a step of compressing the plurality of fragments (F) in the through slot between the two rollers (501 , 502) so as to make the second continuous layer (S2).

12. The method according to any one of claims 1 to 10, wherein the second lamination is a vertical lamination, preferably a multistage, vertical lamination, where each stage (600, 700) comprises a respective pair of rollers (601 , 602, 701 , 702).

13. The method according to claim 12, comprising the following furthersteps:- a second step of fragmenting the second continuous layer (S2) into a plurality of fragments (F) having finished dimensions; said second step of fragmenting being carried out after said second lamination;- a subsequent step of performing a third lamination on the plurality of fragments (F) by means of a third laminating unit (4) comprising at least one respective pair of rollers (801 , 802) to obtain a third continuous layer (S3).

14. The method according to claim 13, wherein the third lamination is a horizontal lamination, preferably multistage, and, in at least a first horizontal lamination stage comprising a pair of opposite rollers (801 , 802), performs a step of mixing the plurality of fragments (F) in an accumulation niche defined between the two opposite rollers (801 , 802), and a subsequent compression of the plurality of fragments (F) in the through slot between the two rollers (801 , 802) so as to make the third continuous layer (S3).

15. The method according to any one of claims 1 to 11 , wherein said first lamination and / or said second lamination comprises a plurality of rollers disposed tangentially to one another to define between them a laminating and processing path for forming the continuous layer.

16. The method according to the preceding claim, wherein the step of fragmenting is performed by at least one cutting roller disposed along the laminating and processing path and provided with at least one cutting projection; the cutting roller being selectively positionable towards and / or away from at least one of the rollers of the laminating and processing path to make the fragments (F).

17. The method according to any one of the preceding claims, wherein said at least one dry product comprises metallic particles and / or powders, in particular said mixture comprising a content of said metallic particles and / or powders comprised between 3% and 30%.

18. A machine (1 ) for making a semifinished, continuous layer, comprising:- a kneader (100) comprising a containing frame, which internally defines a mixing chamber (V), and comprising a motor-driven kneading shaft for mixing at least one dry product and at least one liquid to obtain a mixture; and- a first laminating unit (2), disposed downstream of the kneader (100), comprising at least one pair of laminating rollers (201 , 202, 301 , 302) and configured to perform a step of laminating the mixture to obtain a first layer (S1);- a fragmenting unit (10), disposed downstream of the first laminating unit (2) along a processing path (L) and configured to fragment the first layer (S1) to obtain a plurality of fragments (F) having finished dimensions;- a second laminating unit (3), disposed downstream of the fragmenting unit (10), comprising at least one pair of laminating rollers (501 , 502) and configured to perform a step of laminating the plurality of fragments (F) to obtain a second continuous layer (S2).

19. The machine (1 ) according to the preceding claim, wherein said fragmenting unit (10) comprises at least one automatic cutting station (11 , 15) configured to fragment the first layer (S1) by cutting.

20. The machine (1 ) according to claim 18 or 19, wherein said fragmenting unit (10) comprises an automatic, longitudinal cutting station (11 ), configured to make a plurality of longitudinal cuts; preferably, said automatic, longitudinal cutting station (11 ) comprising a roller (12) provided with a succession of coaxial cutting blades (13).

21. The machine (1 ) according to the preceding claim, wherein said cutting blades (13) are spaced apart from one another by a spacing comprised between 15 mm and 60 mm; said spacing being preferably constant.

22. The machine (1 ) according to any one of claims 18 to 21 , wherein said fragmenting unit (10) comprises an automatic, transverse cutting station (15) configured to make a succession of transverse cuts; said automatic, transverse cutting station (15) comprising at least one transverse blade, oriented transversely to the direction of extension of thefirst layer (S1) and configured to make a cut at regular intervals on the continuous layer (S1); said transverse blade preferably having a length which is greater than or equal to the width of said first layer (S1 ).

23. The machine (1 ) according to the preceding claim, wherein said automatic, transverse cutting station (15) is disposed downstream of the automatic, longitudinal cutting station (11 ).

24. The machine (1 ) according to claim 23 or claim 22 when dependent on claim 20, wherein the automatic, longitudinal cutting station (11 ) and the automatic, transverse cutting station (15) are both disposed upstream of the second laminating unit (3).

25. The machine (1 ) according to any one of claims 18 to 24, comprising a conveyor (4), configured to support the first layer (S1) through the fragmenting unit (10) and preferably also configured and / or disposed to receive the continuous layer (S1 ) which is leaving said first laminating unit (2) and / or to release said plurality of fragments (F) into the second laminating unit (3).

26. The machine (1 ) according to any one of claims 18 to 25, wherein said first laminating unit (2) is a vertical laminating unit comprising at least a first vertical laminating stage (200), preferably comprising a plurality of vertical laminating stages (200, 300) in succession, each stage comprising a respective pair of rollers (201 , 202, 301 , 302).

27. The machine (1 ) according to any one of claims 18 to 24, wherein said second laminating unit (3) is a horizontal laminating unit comprising at least one horizontal laminating stage (500) comprising a respective pair of opposite rollers (501 , 502) configured to perform, in at least a first stage of the horizontal laminating unit, a mixing of the plurality of fragments (F) in an accumulation niche (503) defined between the two rollers (501 , 502), and a subsequent compression of the plurality of fragments (F) in the through slot between the two rollers (501 , 502), so as to make the second continuous layer (S2); preferably, said second laminating unit (3) having a plurality of horizontal laminating stages (500) disposed in succession andeach comprising a respective pair of rollers (501 , 502).

28. The machine (1 ) according to any one of claims 18 to 26, wherein said second laminating unit (3) is a vertical laminating unit comprising at least a first vertical laminating stage (600), preferably comprising a plurality of vertical laminating stages (600, 700) in succession, each stage comprising a respective pair of rollers (601 , 602, 701 , 702).

29. The machine (1 ) according to the preceding claim, comprising:- a second fragmenting unit (20), disposed downstream of the second laminating unit (3) along the processing path (L) and configured to fragment the second continuous layer (S2) to obtain a plurality of fragments (F) having finished dimensions;- a third laminating unit (4), disposed downstream of the second fragmenting unit (20), comprising at least one pair of laminating rollers (801 , 802) and configured to perform a step of laminating the plurality of fragments (F) so as to obtain a third continuous layer (S3).

30. The machine (1 ) according to the preceding claim, wherein said third laminating unit (4) is a horizontal laminating unit, comprising at least one horizontal laminating stage comprising a respective pair of opposite rollers (801 , 802) configured to perform, in at least a first stage of the horizontal laminating unit, a mixing of the plurality of fragments (F) in an accumulation niche defined between the two rollers, and a subsequent compression of the plurality of fragments (F) in the through slot between the two rollers (801 , 802) so as to make the third continuous layer (S3); preferably, said third laminating unit (4) having a plurality of horizontal laminating stages disposed in succession and each comprising a respective pair of rollers (801 , 802).

31. The machine (1 ) according to any one of claims 18 to 30, wherein said first laminating unit (2) and / or said second laminating unit (3) comprises a plurality of rollers disposed tangentially to one another to define between them a laminating and processing path for forming the continuous layer; and wherein the fragmenting unit (10) preferably comprises at least onecutting roller disposed along the laminating and processing path and provided with at least one cutting projection; the cutting roller being selectively positionable towards and / or away from at least one of the rollers of the laminating and processing path to make the fragments (F).

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