IT202000005503A1 - Reconstituted tobacco production method and plant. - Google Patents

Description

DESCRIPTION

of the invention entitled:

"Reconstituted tobacco production method and plant?

The present invention relates to a method and a plant for the production of reconstituted tobacco, both of the conventional type and of the non-conventional type, the latter also referred to as HNB (Heat Not Burn).

Generally speaking, reconstituted tobacco? obtained with the use of tobacco by-products and processing scraps (ribs, small pieces of leaves, powder, etc.) which, appropriately shredded until they are practically reduced to powder and mixed with water, glycerin binders and other liquid additives, they allow to obtain an extremely fluid mixture (slurry) having a liquid content of about 70% by weight, which is then poured in the form of a veil on a steel strip and with this transferred to a drying oven. Here the evaporation of the liquid fraction of the dough takes place, so that the solid residue forms a sort of continuous strip of tobacco having approximately the same width as the steel strip. Subsequently, the dried mixture strip is separated from the steel strip and is cut into pieces of various sizes according to the request. These pieces are then transformed into thin filaments which, suitably mixed, are fed to a traditional cigarette packing machine.

Depending on the raw materials used and, in particular, depending on whether shredded tobacco by-products up to a particle size between 20? M and 320? M are used, or whether crushed tobacco leaves with dimensions between 5 and 10 mm are used, reconstituted tobacco is divided into conventional or unconventional.

WO 2016/050469, WO 2016/050470, WO 2016/050471, WO 25 2016/050472 describe known techniques for the production of reconstituted tobacco, which however require large plants and involve high energy consumption to bring the slurry, which when it is product? rather fluid, to the consistency of a sheet of tobacco. ? it is sufficient to point out that a drying oven can? reach even 100 m in length.

Another drawback of the known techniques for the production of reconstituted tobacco with the use of by-products consists in the fact that the formation of the sheet starting from the slurry veil? rather irregular, as the starting products are not homogeneous and their distribution on the steel strip is not? uniform; it follows that the reconstituted tobacco sheet does not allow it to be coiled, n? to be cut regularly.

Purpose of the invention? to eliminate these drawbacks and to produce both conventional and unconventional reconstituted tobacco, with much larger plants? reduced.

Another purpose of the invention? to produce reconstituted tobacco with limited energy consumption.

Another purpose of the invention? to produce reconstituted tobacco using equipment in part already? available on the market, even if never used in this specific technical sector.

Another purpose of the invention? to produce reconstituted tobacco in an alternative way to traditional methods.

Another purpose of the invention? to produce reconstituted tobacco with characteristics suitable to satisfy different market demands.

Another purpose of the invention? to produce reconstituted tobacco by operating at low temperatures and thus preserving all the aromas of the tobacco.

According to the invention, all these objects and others that will emerge from the following description are jointly or separately achieved with a method of producing reconstituted tobacco according to claim 1 and with an implant according to claim 20.

In particular, the method according to the invention for producing reconstituted tobacco? characterized by the fact of understanding the execution, in sequence, of the following steps:

- the solid components of tobacco are chopped up to bring them to a particle size of about 20 - 320 µm, preferably of about 80-180 µm,

- mix the minced product cos? obtained with water, cellulose in powder form, at least one binding agent and at least one material for forming an aerosol to obtain a slurry with a liquid content of about 30-50%, preferably about 35-40%,

- said mixture is subjected to a first lamination in order to obtain a continuous strip with a thickness of about 1-20 mm, preferably about 1-10 mm, - said strip is subjected already? subjected to said first lamination to a series of further lamination steps, until obtaining a strip having a remarkably constant thickness of about 90 - 280? m, preferably of about 140-200? m, - said strip is dried until its liquid content to about 8-15%.

The present invention is further clarified hereinafter in some of its preferred embodiments reported for purely illustrative and non-limiting purposes with reference to the attached drawings, in which:

Figure 1 shows a schematic general view of a plant for the production of reconstituted tobacco according to the invention, Figure 2 shows its feeding section if the plant is intended for the production of conventional reconstituted tobacco,

figure 3 shows its feeding section in case the plant is intended for the production of reconstituted tobacco of unconventional type (HNB),

figure 4 shows its rib feeding section, figure 5 shows a partial scheme of the plant with two distinct pre-treatment lines of the leaves and the tobacco ribs, figure 6 shows its section of grinding, mixing and storage,

figure 7 is a schematic view of one of its cylinders refiner, figure 8 shows in plan its layering section in a different embodiment.

Figure 9 schematically shows a hot air dryer thereof, and Figure 10 schematically shows its hot air dryer in a different embodiment.

As can be seen from the figures, the plant for producing reconstituted tobacco according to the invention comprises several? sections aimed at operating on the incoming raw materials until they are transformed into a continuous strip of reconstituted tobacco to be sent to the subsequent cigarette packaging operations.

In particular, the plant according to the invention for the production of reconstituted tobacco includes:

- a? unit? of comminution of the solid components of tobacco, to bring them to a particle size of about 20 - 320 µm, preferably of about 80-180 µm; it - a mill 20 and / or a grinder 24 and / or a hammer mill 54;

- a mixer 80, which is fed with quantity doses of comminuted material, with water, with at least one binding agent and with at least one material to form an aerosol, and what? configured to form a slurry with a liquid content of about 30-50%, preferably about 35-40%, - a? unit? of first rolling 100 to obtain from said mixture a continuous strip having a thickness of about 1-20 mm, preferably about 1-10 mm, - a rolling line 116 located downstream of said unit? of first lamination 100 to bring said continuous strip to a thickness of about 90 - 280? m, preferably of about 140-200? m,

- a dryer 122, located downstream of said rolling line 116, to bring the liquid content of said strip, rolled and exiting said rolling line 116, to about 8-15%.

Advantageously, the plant also includes? a? unit? of molding 92 of the mixture for the formation of a plurality? portions 97 of said mixture; appropriately, therefore, the unit? first lamination 100? configured to form from the portions 97 of said mixture a continuous ribbon with a thickness of about 1-20 mm, preferably about 1-10 mm.

Preferably, the plant according to the invention comprises:

- a pre-treatment section of the starting solid products (tobacco leaves, ribs, leaf fragments, powder, etc.) for their preparation for subsequent grinding treatments,

- a grinding and storage section awaiting subsequent mixing with suitable treatment liquids; suitably, said grinding section comprises said unit? shredding,

- a kneading section of solid and liquid materials to obtain a homogeneous dough with a rather dense consistency,

- a section of transformation of the dough, and in particular of a plurality of portions of said mixture, in a continuous belt,

- a rolling line of the continuous strip for its reduction to the desired final thickness,

- a drying section of the laminated strip.

Appropriately, the section for the preparation and pre-treatment of the solid starting products? different depending on whether the plant is intended to produce conventional reconstituted tobacco (fig.2) or non-conventional type (fig.3). Moreover, advantageously, it can? a section for the preparation and pre-treatment of the tobacco ribs (fig. 4), to be used for the production of both conventional and unconventional reconstituted tobacco.

Advantageously, if the preparation and pre-treatment section is intended to feed a plant for the production of conventional reconstituted tobacco (fig. 2), it comprises an overturning 2 of the cartons containing the tobacco by-products, aimed at overturning their content on a feeder 4 of a vibrating conveyor 6, which separates any heavy bodies from the product to be treated. The heavy bodies are collected in a suitable container 8, while the product to be treated is transferred, through a pneumatic conveying line 10, a cyclone 12, a conveyor belt 14, equipped with a metal detector 16 for the removal of any metal bodies, and a pneumatic conveying line 18, to the mill 20, preferably of the cryogenic type.

Advantageously, if the preparation and pretreatment section is provided for the preparation of reconstituted tobacco of an unconventional type (fig. 3), it comprises a feeding station with a bench 22 for unpacking the bales of tobacco leaves from cartons of about 200 kg, which generally contain them, and the transfer of these to a grinder 24.

Conveniently, the output of this grinder 24? connected, through a pneumatic conveying line 26, to a cyclone 28, in which the conveying air is separated from the solid product, which is transferred to a vibrating sieve 30 for the separation of the fine parts from the remaining parts of the product. The exit of the fine parts? directly connected to the cryogenic mill 20, while the output of the remaining parts of the product feeds a traditional twine lever machine 32, which eliminates any twine previously not removed from the bales of tobacco leaves.

The outlet of the twine lever machine 32 feeds a classification chamber 34 for the separation of any heavy foreign bodies from the ground tobacco leaves, which through a pneumatic conveying line 36, a cyclone 38, a belt conveyor 40, equipped with metal detector 42 for the removal of any metal bodies, a weighing system 43 (master scale), and a pneumatic conveying line 44, are transferred to storage and mixing silos 45, from which they can then be transported through another line of pneumatic conveying 44 ?, to the cryogenic mill 20. These silos 45 are dimensioned in order to contain the quantities? of product necessary to form the batch based on the particular recipe to be prepared.

Advantageously, if the preparation and pre-treatment section is provided for the preparation of the tobacco ribs to be used for the production of both conventional and unconventional reconstituted tobacco (fig. 4), it comprises a tilter 46 of cartons containing the tobacco ribs, a rib feeder 48 to a vibrating conveyor 50, for the separation from these of any heavy bodies, and a pneumatic conveying line 52 for their transfer to a hammer mill 54, where they are chopped.

The hammer mill 54 has its outlet in turn connected, by means of a pneumatic conveying line 56 equipped with cyclone filters 58, to one or more? storage silos 60.

The exit of the silo or storage silos 60? in turn connected, by means of a screw conveyor 62, to a weighing system 64 (slave scale), which doses the chopped ribs in the percentage required by the particular recipe to be prepared, before sending them, through the same transport line pneumatic 44?, to storage and mixing silos 45.

How to ? said, the plant according to the invention also includes the mill 20 (fig. 5), which grinds the various products received up to bring them to an average particle size of about 20 - 320? m, preferably of about 80-180? m.

There are various types of mills that can be used, even if? pi? It is advantageous to use a cryogenic pin mill, which allows to keep the product at low process temperatures and therefore to retain the tobacco aromas.

The step mill? in s? traditional and comprises inside a closed structure a fixed disk and a rotating disk or two counter-rotating disks, provided with facing and partially interpenetrating pegs. Being an? Equipment in itself? traditional, it? globally indicated with 20 in fig. 5 and 6 but is not shown in its internal construction characteristics n? in its modalities? of operation.

Preferably, the 20? predisposed to carry out a cryogenic grinding, and what? grinding in the presence of liquid nitrogen.

How to ? said, in a reconstituted tobacco manufacturing plant a cryogenic pin mill 20? somewhat more? advantageous of a traditional mill, essentially for the different modalities? with which the products to be ground are treated. In fact, grinding at room temperature can? lead to obtaining poor quality products? while grinding in the presence of liquid nitrogen allows you to preserve the properties? physical and chemical and organoleptic characteristics of the products.

The quantity of liquid nitrogen used in cryogenic grinding processes? a key part to consider when studying the pros and cons of the process, and can? vary according to the materials processed. Liquid nitrogen at a temperature of -175 ° C is injected onto the product inside the chamber of a screw conveyor 68 which feeds the mill 20 and its residence time in contact with the nitrogen? of about 2 to 5 sec., which? also the transit time of the product inside the screw that feeds the rung mill. The temperature of the product leaving the mill 20? advantageously lower than 10 ° C, so that the nitrogen vapors, which are released almost instantaneously upon contact with the tobacco to be cooled, go through the entire feeding system of the mill in countercurrent, carrying out the desired pre-cooling effect. The flow of liquid nitrogen in the pre-cooling system and in the mill is controlled by thermocouples, which make the cryomind process fully automatic.

In summary, the positive factors of cryogenic grinding are:

- higher yields,

- best quality of the final product without breaking or tearing of the molecular structure,

- decrease of the necessary energy,

- best quality of the final product,

- less quantity? waste due to overheating and oxidation,

- final product pi? homogeneous and more? end,

- less quantity? of material to be reprocessed in the grinding system.

Appropriately, the exit of the cryogenic pin mill 20? connected to a fluid bed sieve 70, which has the function of separating the ground product, which comes out of the mill itself and generally has an average particle size of about 20 - 320? m, preferably of about 80-180? m, from pieces larger, inevitably present.

Conveniently, the fluidized bed sieve 70 therefore has the function of classifying the product and of reintroducing into the mill 20 the one with fractions greater than 300? M, after having separated them from those between 20? M and 320? M, which through a pneumatic conveying line 72 are sent to one or more? mixing and storage silos 74.

Advantageously, the outlet of the mixing and storage silos 74 feeds, through a pneumatic conveying line 76, a cyclone filter 78, which has the function of breaking down the dusty air and more. specifically to separate the dust, which is then recovered and reintroduced into the cycle, from the air, which can then? be expelled.

Conveniently, the outlet of the cyclone filter 78 feeds, through a continuous dosing system, preferably with an auger, the mixer 80, which can? be of various types, for example of the horizontal type with overturning or vertical spiral.

The mixer 80? fed with quantity? doses of crushed tobacco, water, at least one binding agent and at least one material to form an aerosol, and? configured to obtain at the outlet a mixture with a liquid content of about 30-50%, preferably about 35-40%.

In particular, the values of liquid or humidity, indicated in the present description, are intended to be determined according to the measuring system on a wet basis. In particular, the humidity values? are defined as the percentage of water contained in the total mass of the corresponding product and, in other words, as a percentage ratio between the quantity? d? water and the total mass of the assembly. Conveniently, these values are obtained using the traditional methods envisaged in the literature to measure the quantity? of water in a product, such as those presented in? Tobacco Moisture, Water and Oven Volatiles? A status report of common moisture methods used within the tobacco industry? by in? Analytical and bioanalytical chemistry? (1 July 2014, pages 1-16).

Preferably, at least one inlet conduit for water, a material for the formation of aerosols (for example glycerin) and at least one binding agent (binder) is connected to the mixer 80. Conveniently, one or more? inlet ducts for other additives required by the particular recipe to be prepared.

Pi? particularly the plant includes one or more? tanks 82 for the storage of material for the formation of aerosols and one or more? premixers 84, in which pu? said material for the formation of aerosols and, preferably, a plurality of materials can be introduced. of additives dosed in the right proportions to form the liquid to be introduced into the mixer 80.

In order to increase the resistance of the finished product sheet and at the same time to increase the density? of the product itself, the invention envisages introducing in the mixer 80, together with the other components of the mixture, also cellulose in powder with a granulometry preferably between 50 and 100? m in a percentage between 2% and 10% by weight with respect to tobacco. shredded.

This cellulose powder, which before its use? contained in bags or in big-bags, can be introduced directly into the mixer 80 (fig.

1) and in this case, after being poured into a traditional hopper, it is fed to a cyclone filter 78? dosed in the mixer 80.

Alternatively, powdered cellulose can? be introduced, again through a cyclone filter 78? and a continuous dosing system, in the pneumatic conveying line 44? which feeds the mixing and storage silos, from which it is then transferred to the mill 20 (fig. 5) through the pneumatic conveying line 44?, together with the other components of the mixture, present in the line itself. From the mill 20 the contents of the mixing and storage silos 45 are then transferred, through the conveyor line 76, to the weighing device placed at the inlet of the mixer 80.

Examples of preferred materials for aerosol formation (and in particular for the formation of a visible aerosol) include polyhydric alcohols (e.g. glycerin, propylene glycol, triethylene glycol and tetraethylene glycol), aliphatic esters of mono-, di- or polycarboxylic (eg. Methyl-stearate, dimethyl dodecanioate and dimethyltetradecanediate), as well as? their blends. Suitably, glycerin, propylene glycol, triethylene glycol and tetraethylene glycol can be mixed together to form an aerosol-forming material. The material for the formation of the aerosol can? also be provided as a portion of the binding agent (for example, when the binding agent? propylene glycol alginate). Advantageously, suitable combinations of materials for the formation of the aerosol can also be provided.

Preferably, said at least one binding agent (binder) comprises at least one of hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, microcrystalline cellulose, methylcellulose, carboxymethylcellulose (CMC), corn starch, potato starch, guar gum, locust bean gum, pectin and alginates (e.g. ammonium alginate and sodium alginate).

Advantageously, the exit of the premixers 84? connected to an inlet of a hydrator 86, having other inlets connected to a water supply line 88 and to a compressed air supply line 90.

Preferably, the output of the mixer 80 feeds the unit? 92 of forming the dough to obtain a plurality of of portions 97, preferably shaped like loaves / loaves and separated from each other. Conveniently, the unit? 92 comprises a pair of forming cylinders 96, affected by grooves preferably parallel to the axis of the cylinders themselves and intended to take the dough at the inlet and to supply the portions 97 at the outlet. Advantageously, the unit? of forming 92? also? configured to carry out a roughing of the dough and for this purpose, preferably, it comprises a hopper 94 provided with a lump breaker inside it and with said pair of forming cylinders 96 on the bottom.

Advantageously, at the exit of the unit? of forming 92? a conveyor belt 98 is provided for transferring the portions 97 to the unit? of first lamination 100.

Preferably, the unit? of first lamination 100 comprises a lobe feeder 102.

Advantageously, along the transfer path from the unit? of molding 92 to the lobe feeder 102 pu? be provided an additional metal detector 104, having the function of removing any metal parts, which could still be present in the mixture and could damage the subsequent units? processing. These metal parts are conveyed along a distinct path to the inlet of the lobe feeder 102 and are collected in a suitable container 106.

The lobe feeder 102 comprises a series of lobed feed rolls, between which the portions 97 (which come out from the forming rolls 96 of the forming unit 92) are passed so as to be pushed between a pair of rolls lamination 108, which are configured to form a continuous web with a thickness of about 1-20 mm, preferably about 1-10 mm.

Conveniently, in a version not shown of the plant, downstream of the lobe feeder 102 can? the rolling line 116 can be provided directly. In particular, in this case, the rolling line receives at its inlet the single-layer continuous strip, having a thickness of about 1-20 mm, preferably about 1-10 mm, which comes out of the unit. ? of first lamination 100 provided in the lobe feeder 102.

Advantageously, downstream of the unit? of first rolling 100 and upstream of the rolling line 116, pu? be expected a? unit? of stratification 110. Preferably, it? configured to have on more? layers the single-layer continuous tape, having a thickness of about 1-10 mm, which comes out of the unit? of first lamination 100, in order to transform it into a multilayer tape with a thickness of about 2-20 mm, which? then sent in input to the rolling line 116.

Preferably, said unit? of stratification 110 consists of an upstream conveyor belt 112, which has the function of depositing the product belt on an underlying downstream conveyor belt 114, preferably belonging to the rolling line 116, arranging it so that it stratifies on said conveyor belt downstream 114, for example for multiple folding on s? same. Preferably, the upstream conveyor belt 112? raised with respect to the downstream conveyor belt 114 and? equipped with a continuous forward motion with respect to its support structure, and at the same time with an alternating motion with its support structure, parallel to its longitudinal axis.

Conveniently, the unit? of stratification 110 feeds the subsequent and underlying rolling line 116, and depending on the type of plant the upstream conveyor belt 112 of the unit? of stratification 110 pu? be arranged parallel or perpendicular to the rolling line 116. In particular, if the downstream conveyor belts 114 of the rolling line 116 have a width substantially equal to the width of the product belt that leaves the unit? of stratification 110, the upstream conveyor belt 112? arranged parallel to the downstream conveyor belts 114 provided in the rolling line 116 (fig. 1), while if the downstream conveyor belts 114 of the rolling line 116 are more? wide of the product belt coming out of the unit? of stratification 110,? It is preferable that the upstream conveyor belt 112 is arranged orthogonally to the downstream conveyor belts 114 provided in the rolling line 116 (fig. 8), so that with its movements it can distribute the product belt over the entire useful width of the production line lamination 116.

Conveniently, in both cases, the alternating movement of the support structure of the upstream conveyor belt 112 of the unit? of stratification 110 causes a stratification of the product belt, which comes out of the unit? of first rolling 100 on the underlying first downstream conveyor belt 114 of the rolling line 116 and the formation of a stratified belt having a width substantially equal to the useful width of the rolling line itself.

The 116 lamination line? formed by more? rolling stations, each comprising a pair of cylinders 118, which delimit an increasingly narrow passage between them. narrow to progressively reduce the thickness of the web of product being processed. In particular, the rolling line 116? configured to progressively bring the continuous strip to a thickness of 90 - 280? m, preferably about 140-200? m.

Preferably, between each lamination station and the next? a conveyor belt 114 is provided, preferably having a length of about 1.5-2 m, which has the function of letting the product rest before it is subjected to the subsequent rolling step.

Advantageously, the rolling line 116? then completed with one or more? calibration stations, each formed by a pair of calibrating cylinders 120.

? it is advantageously provided that the laminating cylinders 118 and possibly also the calibrating cylinders 120 can be heated, so as to be able to start the drying phase already? during lamination. Conveniently, downstream of the rolling line 116? a dryer 122 is provided, preferably with air recirculation (Fig. 7), to bring the liquid content of said laminated strip to about 8-15%. Advantageously, the dryer 122 can? be divided into two units? 124,126, placed in series with each other. Pi? particularly the unit? 124 upstream? planned to perform the first drying phase and? equipped internally with a steel belt or net belt conveyor for transporting the product that leaves the rolling line 16; the unit? 126 downstream? planned to carry out the second drying phase and the subsequent cooling phase and? equipped with a net belt conveyor inside.

Furthermore, the dryer 122? advantageously provided at the inlet and outlet of sensors 128, preferably with infrared rays, which control the product along its entire length.

The operation of the system described above for the production of conventional reconstituted tobacco (fig. 2)? the following.

Preferably, the tobacco waste containers are placed on the tipper 2, which overturns the products onto the feeder 4, which transfers them to the vibrating conveyor 6. Here, any heavy bodies are separated from the tobacco by-products: the former are collected in the container 8 while the latter are transferred by a flow of air along the pneumatic transport line up to the cyclone 12, which separates the air from the solid products and lets these fall on the conveyor 14, for their transfer, through the pneumatic line 18 , to the cryogenic mill 20.

Preferably, for the production of unconventional reconstituted tobacco instead (fig. 3), the cartons containing the tobacco leaves are placed in the undressing bench 22, where the individual bales of tobacco leaves are removed from the cartons and sent to the grinder. 24, which reduces the leaves themselves to a substantially uniform size between 5 and 10 mm.

Appropriately, the product so? shredded is then transferred along the pneumatic conveying line 26 to the cyclone 28, which separates it from the air and makes it fall onto the vibrating sieve 30.

Here is the separation of the pi? fines, which are sent directly to the cryogenic mill 20, from the remaining parts which, after passing through the twine levering machine 32, reach the classification chamber 34. In this, any heavy bodies are separated from the chopped leaves, which after being subjected at the control of the metal detector 42 they are sent to the cryogenic mill 20.

Conveniently, if the recipe so requires, also shredded tobacco ribs can be transferred to the same cryogenic mill 20, which can be used for the production of reconstituted tobacco of both conventional and unconventional type.

In this case (fig. 4) the containers with the ribs are placed on the overturning device 46, which feeds the ribs themselves to the vibrating conveyor 50 for the removal of any heavy bodies. The ribs are then transferred through the pneumatic line 52 to the hammer mill 54, which shreds them to reduce them to a size between 5 and 8 mm.

From here the shredded ribs, separated in the cyclones 58 from the transport air, are transferred to the storage silos 60, from which the different types of ribs, coming from different qualities? of tobacco, can be withdrawn and transferred through the screw conveyor 62 to the rib dispenser 64, which doses them according to the particular recipe to be prepared.

Ribs chopped and dosed in the correct quantities? are transferred through the pneumatic line 66 to the cryogenic mill 20.

Advantageously, regardless of the type of reconstituted tobacco to be produced, and therefore of the type of solid parts of tobacco introduced into the unit? of shredding, from the latter comes out a ground product with an average grain size of about 20 - 220? m, preferably of about 80-180? m. Preferably, the ground product, which comes out of the fluidized bed sieve fed by the cryogenic mill 20, has an average particle size of about 20 - 220 µm, preferably of about 80-180 µm.

Advantageously, the product so? ground is sent to the mixing and storage silos 60, from which the products can then be taken as needed and transferred to the mixer 80.

In addition to the ground tobacco and cellulose and in general all the solid products coming from the mixing and storage silos 45, water, at least one binding agent and at least one material are also introduced into the mixer 80 to form an aerosol. Advantageously, compressed air and other additives can also be introduced, including in particular ground cloves.

Conveniently, the whole is then mixed together to form a slurry having a percentage of liquids (humidity) of about 30-50%, preferably about 35-40%, by weight on a wet basis, i.e. a rather thick consistency.

Preferably, the dough so? obtained is transferred to the unit? of molding 92, from which come out a plurality? of portions 97, preferably shaped like loaves.

These portions of dough 97, which come out of the unit? of forming 92 are suitably transferred to the unit? of the first lamination 100 which? configured to output a continuous web with a thickness of about 1-20 mm, preferably about 1-10 mm.

This continuous tape, which comes out of the unit? of first lamination 100, is transferred directly to the lamination line 116 or? through the unit? of layering 110 - is folded on s? same to be so? deposited in layered form on the inlet belt 114 of the rolling line 116.

Appropriately, how do you? said, the layering? obtained by letting the continuous belt fall onto the conveyor belt 112, which is made to advance with respect to its support structure, which is moved by reciprocating motion, so as to be arranged on several layers the product belt on said inlet conveyor belt 114. Depending on the plant and the direction of the alternating movement of the support structure of the conveyor belt 112 immediately downstream of the unit? of stratification 110, the product web is arranged on several? layers parallel to the longitudinal direction of the rolling line 116 or orthogonal to it.

Conveniently, at each passage from one station to another of the rolling line 116, the product strip undergoes a reduction in thickness, until it reaches the desired thickness in correspondence with the output calibrating cylinders 120, which has a significantly constant value of about 90. - 280? M, preferably about 140-200? M. Advantageously, moreover, at the exit from the rolling line 116 the strip has a liquid content lower than 20% or even 15%, if the laminating cylinders 118 are heated and the removal of the water has already started. during lamination.

The web of product that leaves the rolling line 116 is then subjected to drying in the dryer 122, where its liquid content is brought to about 8-15%.

Preferably, the dryer 122? with recirculation of air, and compared to the dryers traditionally used in the production of reconstituted tobacco? somewhat more? advantageous both in terms of complexity? in terms of overall dimensions and in terms of energy consumption. There? as traditional plants treat a very fluid and not very stable product (slurry), unlike the product treated by the plant according to the invention, which? much more? dense and much more? stable. Consequently, while the plants that treat slurry require traditional irradiation and conduction dryers, the plant according to the invention can? advantageously to use a recirculating air dryer 122 with a network belt conveyor or a combined system of steel belt conveyors for the first drying phase and network belt conveyors for the second drying phase and for the drying phase. cooling down. In this way they are obtained, at par? of performance, reduced dimensions (about 45 m compared to over 100 m of a traditional dryer) and lower energy consumption given the smaller quantity? of water to be removed (using about 1000 kg / hour of steam / hour compared to over 5000 kg / hour of steam in a traditional dryer).

Conveniently, at the exit of the dryer 122 the product? ready to be wound on a reel or to be cut into threads of predetermined dimensions, to be used for the packaging of cigarettes.

Conveniently, if the plant is intended for the production of reconstituted tobacco of an unconventional type, in addition to using a different preparation and treatment section, and already? described, uses, as an alternative to the unit? 92 or in addition and upstream of this, a refiner with cylinders 130 which has the task of bringing the solid components of the mixture to a granulometry not exceeding 20? m.

The refiner (fig. 7) comprises inside a closed container a plurality of of cylinders 132 arranged in sequence in close proximity to each other, so as to delimit corresponding grinding slots. The bottom cylinder 132? ? mounted with the axis outside the plane containing the axis of all the other cylinders 132 and acts as a feeder of the dough which is taken from the bottom of the container and made to rise upwards in order to pass between the lower cylinder and the one immediately above and then to follow among all the others. The various pairs of cylinders 132, between which the dough passes, rotate at different speeds, in the sense that the upper cylinder rotates at different speeds. greater than the lower cylinder, with which it cooperates, so as to subject the dough to stretching during the passage between the cylinders 132 of each pair and thus to reduce the size of the particles of the dough itself. Indeed, one of the fundamental parameters for the success of the refining process? just the different speed? of the various cylinders 132, on which the passage of the whole mass of dough that has passed through the grinding slot depends.

The pressure between the cylinders? hydraulically controlled.

All cylinders 132 are cooled with cold water which circulates inside each cylinder and in this way contrasts the heat, which develops from the mixture due to the friction due both to the movement of the cylinders and to the rubbing with the product. In this way the temperature of the product mass is reduced until it reaches 25 ° C.

Thanks to the refiner 130 just described, the friction action, which is exerted on the dough by the cylinders 132 of the latter, develops a considerable binding action of the cellulose fibers contained in the tobacco and in particular in the ribs of the latter, and this involves the double advantage of developing the aromatic components of the product and eliminating the need? to introduce more fiber into the mixture to obtain the required binding effect.

The operation of the plant in this different embodiment provides that the shredded leaves and the shredded ribs coming from the preparation and pre-treatment stations are fed to the cryogenic pin mill 20 in quantity. proportionally dosed according to the recipe to be obtained, and are brought by this to a particle size of about 20 - 320 µm, preferably of about 80-180 µm.

The product is then transferred with the modality? already? described in the mixer 80, in which a mixture of product is formed as described above.

The dough so? obtained is then fed to the cylinder refiner 130, which has the task of bringing the solid components of the mixture to a granulometry not exceeding 20? m. In this way, the friction action exerted on the dough by the cylinders 132 of the refiner 130 develops a considerable binding action of the cellulose fibers contained in the tobacco and in particular in the ribs of the latter, and this is the case. it entails the double advantage of developing, on the one hand, the aromatic components of the product and, on the other hand, of eliminating the need? to introduce more fiber into the mixture to obtain the required binding effect.

In fig. 1? schematically indicated the position of the refiner 130 between the mixer 80 and the unit? of forming 92, but the invention also provides that the refiner 130 can be an alternative to the unit? of forming 92, and in this case the mixture that comes out of the refiner 130 is transferred directly to the unit? of first rolling 100, for the continuation of the processing cycle according to the modalities? already? described.

Claims (37)

CLAIMS 1. Method for producing reconstituted tobacco characterized by the fact that: - the solid components of tobacco are chopped up to bring them to a particle size of about 20 - 320 µm, preferably of about 80-180 µm, - mix the minced product cos? obtained with powdered cellulose, water, at least one binding agent and at least one material for forming an aerosol to obtain a slurry with a liquid content of about 30-50%, preferably about 35-40%, - said mixture is subjected to a first lamination in order to obtain a continuous strip with a thickness of about 1-20 mm, preferably about 1-10 mm, - said strip is subjected already? subjected to said first lamination to a series of further lamination steps, until obtaining a strip having a remarkably constant thickness of about 90 - 280? m, preferably of about 140-200? m, - said strip is dried until its liquid content to about 8-15%. 2. Method according to claim 1, characterized in that the dried continuous web is subjected to winding or shredding into threads of predefined dimensions. 3. Method according to one or more? of the preceding claims, characterized in that the solid components of the tobacco are crushed by grinding. 4. Method according to one or more? of the preceding claims, characterized in that the solid components of the tobacco are crushed with a mill. 5. Method according to one or more? of the preceding claims, characterized in that the solid components of the tobacco are crushed with a cryogenic pin mill (20). 6. Method according to one or more? of the preceding claims characterized in that said mixture is formed with powdered cellulose having a particle size of between 50 and 100 µm. 7. Method according to one or more? of the preceding claims characterized in that said mixture is formed with powdered cellulose in a percentage comprised between 2% and 10% of the weight of the tobacco. 8. Method according to one or more? of the preceding claims characterized in that ground cloves are added to the mixture. 9. Method according to one or more? of the preceding claims characterized in that the crushed tobacco components are mixed with powdered cellulose before forming said mixture with them. 10. Method according to one or more? of the preceding claims characterized in that the mixture formed by comminuted product, powdered cellulose, water, at least one binding agent and at least one material is submitted to form an aerosol: - to a roughing step by passing through at least a pair of grooved cylinders (92) and / or - to a refining step by passing through at least a pair of refining cylinders (132.132?) until it reaches a grain size not exceeding 20? m. 11. Method according to one or more? of the preceding claims characterized in that said mixture is subjected to a step of homogenization and forming before subjecting it to said first rolling step. 12. Method according to claim 9 characterized by the fact that said mixture is subjected to a homogenization and shaping phase for its transformation into a continuous strip, with a substantially constant width between 100 and 2000 mm and thickness between 1 and 10 mm , to then be subjected to said first lamination step. 13. Method according to claim 10 characterized in that said mixture is subjected to a step of homogenization and shaping for its transformation into a sequence of portions (97) to be then subjected to said first rolling step. 14. Method according to one or more? of the preceding claims characterized in that said first rolling of the mixture is carried out with a unit? (100) comprising a lobe feeder (102) and at least one pair of lamination rolls (108). 15. Method according to one or more? of the preceding claims characterized in that at the outlet of said first lamination a single-layer strip with a thickness of about 1-10 mm is obtained. 16. Method according to one or more? of the preceding claims characterized by the fact that, before said series of further rolling steps, said strip is subjected, already? subjected to said first lamination, to stratification until obtaining a multilayer tape with a thickness of about 2-20 mm. 17. Method according to one or more? of the preceding claims characterized in that, in said series of further rolling steps, the dough is allowed to rest between one rolling station and the next. 18. Method according to one or more? of the preceding claims characterized in that lamination is carried out with pairs of at least partly heated cylinders (118). 19. Method according to one or more? of the preceding claims characterized in that said laminated strip dries by passing through a recirculating air dryer (122). 20. Plant for the production of reconstituted tobacco characterized by the fact of comprising: - a? unit? of comminution (20,24,54) of the solid components of tobacco, to bring them to a particle size of about 20 - 220? m, preferably of about 80-180? m, - a? mixer (80) which? fed with quantity? doses of comminuted material, powdered cellulose, water, at least one binding agent and at least one material to form an aerosol, and what? configured to obtain a mixture with a liquid content of about 30-50%, preferably about 35-40%, - un? unit? of first rolling (100) to obtain, from said mixture, a continuous strip with a thickness of about 1-20 mm, preferably about 1-10 mm, - a rolling line (116) located downstream of said unit? of first lamination (100) to bring said continuous strip to a thickness of 90 - 280? m, preferably of about 140-200? m, - a dryer (122) to bring the liquid content of said laminated strip to about 8-15%. 21. Plant according to the preceding claim, characterized in that said dryer? with recirculation of air. 22. Plant according to one or more? of the previous claims, characterized by the fact that said unit? shredding includes a mill (20). 23. Plant according to one or more? of the preceding claims characterized by the fact that said unit? shredding includes a cryogenic pin mill. 24. Plant according to one or more? of the preceding claims characterized in that it comprises upstream of said mill (20) at least one silo (45) for mixing and storing the solid material comprising said crushed tobacco components and said powdered cellulose. 25. Plant according to one or more? of the preceding claims characterized in that it comprises, downstream of said mixer (80) and upstream of said unit? of first lamination (100), a? unit? of shaping (92) of the dough. 26. Plant according to one or more? of the preceding claims characterized by the fact that said unit? forming (92)? also? configured to homogenize the mixture. 27. Plant according to one or more? of the preceding claims characterized by the fact that said unit? forming (92)? configured to transform the dough into a continuous belt with a significantly constant width between 100 and 2000 mm and thickness between 1 and 4 mm. 28. Plant according to one or more? of the preceding claims characterized by the fact that said unit? forming (92)? configured to divide said mixture into a plurality of of portions (97) to be sent to said unit? of first lamination (100). 29. Plant according to one or more? of the previous claims characterized by the fact that the unit? (92) comprises a roughing machine with at least one pair of grooved rolls (96) and / or a roll refiner (130). 30. Plant according to one or more? of the preceding claims characterized by the fact that said unit? of first lamination (100) comprises a lobe feeder (102) and at least one pair of lamination rolls (108). 31. Plant according to one or more? of the preceding claims characterized by the fact of comprising downstream of said unit? of first lamination (100) a? unit? stratification (110). 32. Plant according to the preceding claim characterized in that said unit? of layering (110) comprises an upstream conveyor belt (112) which? powered by that unit? of first lamination (100) and what? equipped with continuous movement with respect to its support structure, which? equipped with alternating movement with respect to an underlying downstream conveyor belt (114), preferably of said rolling line (116). 33. Plant according to one or more? of the preceding claims characterized in that said rolling line (116) comprises a plurality of products. of rolling stations separated from each other by conveyor belt sections (114) of sufficient length to allow the product belt to rest between one lamination station and the next. 34. Plant according to one or more? of the preceding claims characterized in that at least part of the rolls (118,120) of said rolling line (116) are heated. 35. Plant according to one or more? of the preceding claims characterized in that said hot air dryer (122) comprises a first unit? (124), in which a first drying phase of the product web that leaves the rolling line (116) is carried out, and a second unit? (126), placed in series with the first, in which a second drying phase and a subsequent cooling phase of the product web is performed, already? partially dried, which comes out of the first unit? (124) 36. Plant according to claim 31 characterized in that at least one mesh conveyor is used inside said hot air dryer (122). 37. Plant according to claim 31 and / or 32 characterized in that said hot air dryer (122)? provided inside the said first unit? (124) of a steel belt or net belt conveyor and inside said second unit? (126) of a net belt conveyor.