Methods and Apparatus for Producing Reconstituted Tobacco - Patent application

Abstract

1. A method for producing reconstituted tobacco, comprising: - the tobacco solid component is ground to a particle size of approximately 20 to 220 μm, preferably 80 to 180 μm; the ground material thus obtained is mixed with water, powdered cellulose, at least one binder and at least one material for forming an aerosol until a slurry is obtained with a liquid content of about 30-50%, preferably about 35-40%; - the mixture is subjected to a first lamination in order to obtain continuous strips having a thickness of about 1 to 20 mm, preferably about 1 to 10 mm, - the strips already subjected to the first lamination are subjected to a series of further first lamination steps until strips having a very constant thickness of between about 90 and 280 mm, preferably between about 140 and 200 mm, are obtained; - The strips are dried until their liquid content is approximately 8-15%. A method characterized by:

Description

[Technical field]

[0001] The present invention relates to methods and apparatus for the production of reconstituted tobacco, both conventional and non-conventional, the latter also known as HNB (Heat Not Burn). [Background technology]

[0002] Generally, reconstituted tobacco is obtained using tobacco by-products and waste products (veins, leaf shreds, flour, etc.), which are mostly powdered and suitably ground to be mixed with water, glycerin binder and other liquid additives, making it possible to obtain a very fluid mixture (slurry) with a liquid content of about 70% by weight, which is then poured onto a steel strip, thereby transferring it to drying. Here, evaporation of the liquid fraction of the mixture occurs, so that the solid residue forms a kind of continuous strip of tobacco with approximately the same width as the steel strip. The dried strip of mixture is then separated from the steel strip and cut into strips of various sizes as required. These strips are then transformed into thin filaments, which are suitably mixed and fed into a conventional cigarette packing machine.

[0003] Depending on the raw materials used, and in particular whether shredded tobacco by-products with a particle size between 20 μm and 220 μm at most are used, or ground tobacco leaves with dimensions between 5 and 10 mm, reconstituted tobacco is differentiated as conventional or non-conventional.

[0004] WO 2016 / 050469, WO 2016 / 050470, WO 2016 / 050471 and WO 2016 / 050472 describe known techniques for the production of reconstituted tobacco, but the known techniques require large equipment and involve high energy consumption in bringing the consistency of the slurry to that of a tobacco sheet when the product is rather fluid. It suffices to point out that drying ovens can reach lengths of up to 100 meters.

[0005] Another drawback of the known techniques for producing reconstituted tobacco using by-products is that the formation of the sheet resulting from the slurry film is rather irregular, since the starting product is not homogeneous and its distribution on the steel strip is not uniform. Said drawback results from the inability to regularly roll or cut the reconstituted tobacco sheet.

[0006] WO 2019 / 157576 describes a method for the preparation of reconstituted pieces of plant material, in which a preliminary rolling Stages and Final rolling Between the stages, the preliminary rolling Remixing of the separated sheets is effected inside the mixer to obtain a homogeneous mass, which is then mixed into the final product. rolling For use.

[0007] WO 2020 / 058814 discloses a method for the preparation of reconstituted tobacco, in which a solid component of shredded tobacco is mixture is mixed with water, at least one binder, and at least one material to form an aerosol until the liquid content is about 30 to 50 percent, preferably about 35 to 40 percent.

[0008] WO 2016 / 067226 describes a method for preparing reconstituted tobacco, said reconstituted tobacco comprising a first drying unit, a grinding unit, a mixing unit for a solid component (i.e. tobacco powder with a solid powder of a natural binder), a mixing unit for a liquid component (i.e. a liquid / nanogel containing propylene glycol and glycerin), a unit for mixing the solid mixed component with the liquid mixed component, and one to three units for obtaining a membrane of 0.15 to 0.3 mm. rolling The unit includes a dryer for reducing the moisture content of the membrane. Summary of the Invention

[0009] The object of the present invention is to eliminate these drawbacks and to produce conventional and non-conventional reconstituted tobaccos using smaller equipment.

[0010] Another object of the present invention is to produce reconstituted tobacco while limiting energy consumption.

[0011] Another object of the present invention is to produce reconstituted tobacco using equipment that is already partially available on the market, even if it has never been used in this particular technical field.

[0012] Another object of the present invention is to produce reconstituted tobacco in an alternative manner to conventional methods.

[0013] Another object of the present invention is to produce reconstituted tobacco with suitable properties to meet the demands of various markets.

[0014] Another object of the present invention is to produce reconstituted tobacco by operating at low temperatures, thereby preserving all of the tobacco aroma.

[0015] According to the present invention, all these objects, as well as other objects arising from the following description, are achieved jointly or separately by a method for producing reconstituted tobacco according to claim 1 and by an apparatus according to claim 23.

[0016] Specifically, the method for producing reconstituted tobacco of the present invention comprises the steps of: - the solid components of the tobacco are ground to a particle size of approximately 20 to 220 μm, preferably 80 to 180 μm; the resulting ground material is mixed with water, powdered cellulose, at least one binder and at least one material for forming an aerosol, with a liquid content of about 30-50%, preferably about 35-40%; mixture mixing until - the mixture is subjected to a first process to obtain continuous strips having a thickness of about 1 to 20 mm, preferably about 1 to 10 m. Rolling process receiving the -Already in point 1 above Rolling process The strip is then subjected to a series of further grinding processes until a strip having a very consistent thickness of about 90 to 280 mm, preferably about 140 to 200 mm, is obtained. rolling A process that undergoes a process; - the strips are dried until their liquid content is about 8-15%. The method is characterized by the fact that it includes the steps of: [Brief description of the drawings]

[0017] The invention will be further defined hereinafter in some of its preferred embodiments, reported purely for illustrative and non-limiting purposes with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 shows a general schematic diagram of an apparatus for producing reconstituted tobacco according to the present invention. [Diagram 2] Where the apparatus is intended for the production of conventional reconstituted tobacco, the supply is shown. [Diagram 3] Where the apparatus is intended for the production of non-conventional (HNB) reconstituted tobacco, the supply is indicated. [Figure 4] 1 shows the vein feed portion of the device. [Diagram 5] FIG. 1 shows a partial configuration of an apparatus with two separate lines for pre-processing of leaves and tobacco veins. [Figure 6]Parts of the equipment for grinding, mixing and storage are shown. [Figure 7] FIG. 1 shows a schematic diagram of a refiner having a cylinder. [Figure 8] 1 shows a plan view of the layered parts of the device in different embodiments; [Figure 9] 1 shows a schematic diagram of a hot air dryer of the device. [Figure 10] 1 shows a schematic diagram of a hot air dryer of the apparatus in one different embodiment.

[0018] As can be seen in these figures, an apparatus for producing reconstituted tobacco according to the present invention includes a number of sections designed to operate on the input raw materials until they are transformed into continuous elongated strips of reconstituted tobacco for subsequent tobacco packaging operations. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In particular, the device according to the invention for the production of reconstituted tobacco comprises: - a unit for shredding the solid components of the tobacco to a particle size of approximately 20 to 220 μm, preferably approximately 80 to 180 μm; - mills 20 and / or grinders 24 and / or pin mills 54, a mixer 80 configured to receive the shredded material of the feed, water, at least one binder, and at least one material for forming an aerosol and to form a mixture with a liquid content of about 30-50%, preferably about 35-40%; a first rolling unit 100 for obtaining continuous strips from said mixture having a thickness of about 1 to 20 mm, preferably about 1 to 10 mm; a rolling line 116 located downstream of the first rolling unit for bringing the continuous strip to a thickness of about 90 to 280 μm, preferably about 140 to 200 μm; and a dryer 122 disposed downstream of the rolling line 116 for reducing the liquid content of the rolled strips leaving the rolling line 116 to about 8-15%.

[0020] Conveniently, the apparatus further comprises a mixture forming unit 92 for forming a plurality of portions 97 of said mixture, suitably whereby the first rolling unit 100 is configured to form from said mixture portions 97 continuous strips having a thickness of about 1-20 mm, preferably about 1-10 mm.

[0021] Preferably, the device according to the invention comprises: - Pre-processing of the starting solid product (tobacco leaves, veins, leaf fragments, powder, etc.) in order to prepare it for subsequent milling processing; a grinding section and a storage section, after which mixing with a suitable processing fluid is awaited, said grinding section officially comprising said grinding frame unit; a mixing section for mixing the solid and liquid materials to obtain a homogeneous mixture having a relatively high density; a part for transforming the mixture, and in particular the parts of said mixture, into a continuous band, - a rolling line for reducing the continuous strip to a desired final thickness; - rolling and a drying portion of the web.

[0022] Conveniently, the sections for preparation and pre-processing of the starting solid product are different depending on whether the apparatus is intended to produce conventional (FIG. 2) or non-conventional (FIG. 3) reconstituted tobacco. Moreover, conveniently, a section for preparation and pre-processing of tobacco veins may further be provided for use in the production of both conventional and non-conventional reconstituted tobacco (FIG. 4). Moreover, advantageously, a section for preparation and pre-processing of tobacco veins may also be provided for use in the production of both conventional and non-conventional reconstituted tobacco (FIG. 4).

[0023] Advantageously, if the preparation and pre-processing section is intended to feed a conventional apparatus for the production of reconstituted tobacco (FIG. 2), it includes a tilter 2 of cartons containing the tobacco by-product, the aim of which is to turn their contents over on a feeder 4 of a vibrating conveyor 6 which separates any heavy mass from the product to be processed. The heavy mass is collected in a suitable container 8, while the product to be processed is transferred, via a pneumatic conveyor 10, a cyclone 12, a conveyor belt 14 equipped with a metal detector 16 for the removal of any metal objects, and a pneumatic conveyor 18, to a preferably cold mill 20.

[0024] Advantageously, when the preparation and pre-processing section is provided for the preparation of non-conventional reconstituted tobacco (FIG. 3), it includes a feeding station using benches 22 for unpacking tobacco leaves (typically contained) from cartons of about 200 kg and transferring them to a grinder 24.

[0025] Conveniently, the outlet of the grinder 24 is connected through an air conveyance 26 to a cyclone 28 in which the conveying air separates from the solid product which is then passed to a vibrating sieve 30 for separating the fine fraction from the remainder of the product. The output of the fine fraction is connected directly to the cold mill 20 and the output of the remainder of the product feeds a conventional yarn levelling machine 32 which removes any yarn not previously removed from the tobacco bale.

[0026] The outlet of the yarn levering machine 32 feeds into a classification chamber 34 for separating any heavy foreign matter from the ground tobacco leaves, which is then passed through a pneumatic conveyor 36, a cyclone 38, a conveyor belt 40 equipped with a metal detector 42 for removing any metal objects, a weighing system 43 (standard scales), and a pneumatic conveyor 44, which moves them to storage and mixing silos 45, which can be transported to the cold mill 20 using another method of pneumatic conveyor 44'. These silos 45 are sized to contain the amount of product required to form a batch according to the particular recipe being prepared.

[0027] Advantageously, when the preparation and pre-processing section is provided for the preparation of tobacco vein used in the production of conventional and non-conventional reconstituted tobacco (FIG. 4), it includes a carton tilter 46 containing the tobacco vein, a vein feeder 48 to a vibratory conveyor 50 for separating any weights therefrom, and a pneumatic conveyance 52 for feeding them to a pin mill 54 for crushing.

[0028] The pin mill 54 has an outlet which is in turn connected to one or more storage silos 60 by means of a pneumatic conveying 56 equipped with a cyclone filter 58 .

[0029] The outlet of the silo or silos 60 is connected by means of a screw conveyor 62 to a weighing system 64 (slave scale), which performs the grinding of the veins to the percentage required for the particular recipe being prepared, before sending them via pneumatic conveying 44 to the storage and mixing silo 45.

[0030] As already mentioned, the apparatus according to the invention also includes a mill 20 (FIG. 5), which grinds the various products received until they reach an average particle size of about 20 to 220 μm, preferably about 80 to 180 μm.

[0031] There are various types of mills that can be used, but it is advantageous to use a low temperature pin mill, which allows the product to be maintained at low processing temperatures and therefore retains the tobacco aroma.

[0032] A pin mill is conventional in itself and comprises a fixed and rotating or counter-rotating disc within a closed structure, with opposing and partially penetrating pins. Being a conventional device in itself, it is shown generally at 20 in Figures 5 and 6, but not its internal construction features, nor its mode of operation.

[0033] Preferably, the pin mill 20 is designed to perform cryogenic grinding, i.e., grinding in the presence of liquid nitrogen.

[0034] As mentioned, in a reconstituted tobacco production system, the cold pin mill 20 has some advantages over conventional mills, essentially due to the different ways in which it processes the ground product. Indeed, while grinding at room temperature can result in a poor quality product, grinding in the presence of liquid nitrogen makes it possible to preserve the physical, chemical and organoleptic properties of the product.

[0035] The amount of liquid nitrogen used in the cryogenic grinding process is a key point to consider when investigating the pros and cons of the process and can vary depending on the material being processed. Liquid nitrogen at a temperature of -175°C is injected into the product in the chamber of the screw conveyor 68 that feeds the mill 20 and the residence time in contact with the nitrogen is approximately 2-5 seconds, which is also the travel time of the product inside the screw that feeds the pin mill. The temperature of the product leaving the mill 20 is advantageously less than 10°C, so that the nitrogen vapour released almost instantly on contact with the tobacco being chilled creates the desired pre-cooling effect by flowing back through the entire feed system of the mill. The pre-cooling system, and the flow of liquid nitrogen in the mill, are controlled by thermocouples, making the cryomind process fully automated.

[0036] In summary, the positive factors of cryogenic grinding are: - High yield, - Better quality of the final product without breaking or tearing the molecular structure, - Less energy required, - better quality of the final product, - Reduction of waste from overheating and oxidation, - A more homogeneous and precise end product, - Reduction in the amount of material that needs to be reprocessed in the grinding system.

[0037] Conveniently, the outlet of the cold pin mill 20 is connected to a fluidized bed sieve 70, which serves to separate the milled product exiting the mill itself and inevitably from the larger sizes, generally having an average particle size of about 0-220 μm, preferably about 80-180 μm.

[0038] Conveniently, the fluidized bed sieve 70 thus serves to classify the product and reintroduce it, with the fraction above 220 μm, into the mill 20 after separating the fraction between 20 μm and 220 μm which is sent via pneumatic conveying 72 to one or more mixing and storage silos 74.

[0039] Advantageously, the outlet of the mixing and storage silo 74 is fed, by means of a pneumatic conveying line 76, to a cyclone filter 78, which has the function of breaking down the dusty air, in particular separating the dust which is then recovered and reintroduced into the cycle, from the air which may then be discharged.

[0040] Conveniently, the outlet of the cyclone filter 78 feeds a mixer 80 through a continuous dosing system, preferably using a screw, which may be of many types, for example a horizontal inclined type or a vertical spiral type.

[0041] Mixer 80 is configured to receive metered amounts of ground tobacco, water, at least one binder, and at least one ingredient to form an aerosol, and to obtain a mixture having a liquid content of about 30-50%, preferably about 35-40%.

[0042] More specifically, the liquid or moisture values ​​indicated herein are intended to be determined according to a metering system using a wet weight standard. More specifically, the moisture value is defined as the percentage of water contained in the total mass of the corresponding product, in other words the percentage ratio between the amount of water and the total mass of the assembly. Conveniently, these values ​​are obtained using traditional methods provided in the literature for measuring the amount of water in products (such as those listed in “Tobacco Moisture, Water and Oven Volatiles - A status report of common moisture methods used within the tobacco industry ”By Nils Rose ET AL. in “Analytical and bioanalytical chemistry” (July 1, 2014, pages 1-16)).

[0043] Preferably, at least one duct for the inlet water, the material for the formation of the aerosol (for example glycerin), at least one binder is connected to the mixer 80. Conveniently, one or more inlet ducts can be provided for other additives required by the particular recipe to be prepared.

[0044] More specifically, the apparatus includes one or more storage tanks 68 for aerosol forming substances, and one or more pre-mixers 84 into which the materials for forming the aerosol, preferably multiple additives, can be introduced in the correct ratio to form the liquid that is introduced into the mixer 80.

[0045] In order to increase the resistance of the final product sheet and at the same time the density of the product itself, the final product is preferably introduced into the mixer 80 together with the other components of the mixer and also with powdered cellulose. Conveniently, the cellulose powder used is made of organic fibres obtained from natural cellulose, rather than compounds derived from cellulose. The powdered cellulose thus added preferably has a particle size of 50 to 100 μm, and the powdered cellulose is preferably present in a proportion of between 2 and 10% by weight relative to the ground tobacco.

[0046] The powdered cellulose added is mainly or exclusively of natural origin, more particularly, said powdered cellulose added in this way is not synthetic and is not obtained by chemical processing.

[0047] Advantageously, the powdered cellulose added in this way does not have a binding function, but does have the function of lowering the specific gravity of the final product and reducing the solid content of the tobacco, thereby reducing the cost of the final product, since cellulose is much less expensive than tobacco. Furthermore, the addition of cellulose makes the final product stronger by increasing the tensile strength, so that the final product can be processed more easily, which is particularly useful when the final product is also a pleated sheet.

[0048] The powdered cellulose can be contained in bags or big bags prior to its use and introduced directly into the mixer 80 (FIG. 1), in which case, after being poured into a conventional hopper, it is fed into a cyclone filter 78′ which, via a continuous dosing system, preferably of the screw type, introduces the powdered cellulose in a weighted form into the mixer 80.

[0049] Alternatively, the powdered cellulose can be introduced in the pneumatic conveying line 44', again via a cyclone filter 78' and a continuous dosing system, which feeds the mixing and storage silo, from which the powdered cellulose is then transferred, together with the other components of the mixture present in the line itself, via the pneumatic conveying line 44' to the mill 20 (FIG. 5). From the mill 20, the contents of the mixing and storage silo 45 are conveyed through the conveying line 76 to a metering system arranged at the inlet of the mixer 80.

[0050] Preferred materials for aerosol formation (and more specifically for visible aerosol formation) include, for example, polyhydric alcohols (e.g., glycerin, propylene glycol, triethylene glycol and tetraethylene glycol), aliphatic esters of mono-, di- or polycarboxylic acids (e.g., methyl stearate, dimethyl dodecane and dimethyl tetradecane), and mixtures thereof as well. Suitably, glycerin, propylene glycol, triethylene glycol and tetraethylene glycol can be mixed together to form an aerosol-forming material. Furthermore, the aerosol-forming material can be provided as part of the binder (e.g., when the binder is propylene glycol alginate). Advantageously, a suitable combination of materials for aerosol formation can also be provided.

[0051] Preferably, at least one of the above of The binder is Hide hydroxypropyl cellulose, Hide propyl methylcellulose, Hide hydroxyethyl cellulose, microcrystalline cellulose, methyl cellulose, carboxymethyl cellulose (CMC), corn starch, potato starch, Guar gum , locust bean gum, pectin, and alginates (e.g., ammonium alginate and sodium alginate).

[0052] Preferably, the binder and the added powdered cellulose are defined by different materials.Conveniently, the powdered cellulose mainly serves to form a three-dimensional framework, which has high thickening effect, pseudoplasticity and good ability to hold liquid, while the binder exclusively or mainly serves to bind the various components that are mixed together.

[0053] Conveniently, the outlet of the pre-mixer 84 is connected to the inlet of a hydrator 86 which has other inlets connected to a water supply line 88 and a compressed air supply line 90 .

[0054] Preferably, the outlet of said mixer 80 feeds a unit 92 for forming said mixture, preferably separated from one another in the form of lobes, to obtain a plurality of portions 97. Conveniently, said forming unit 92 comprises a pair of forming cylinders 96, which present grooves, preferably parallel to the axis of said cylinders themselves, intended to pick up said mixture at said inlet and to provide said portions 97 at said outlet. Conveniently, said unit 92 is further adapted to perform a roughening of said mixture, and for this purpose preferably comprises a hopper 94, which is provided with a lump breaker inside and with said pair of forming cylinders 96 at the bottom.

[0055] Conveniently, at the exit of the forming unit 92 a conveyor belt 98 is provided for transporting the portion 97 to a first rolling unit 100 .

[0056] Preferably, the first rolling unit 100 includes a lobe feeder 102 to homogenize the mixture formed by the portions 97 .

[0057] Advantageously, a further metal detector 104 can be provided along the transport path from the forming unit 92 to the lobe feeder 102, the metal detector 104 having the function of removing any metal parts present in the mixture that may damage subsequent processing units. These metal parts are conveyed along a separate path to the inlet of the lobe feeder 102 and collected in a suitable container 106.

[0058] The lobe feeder 102 includes a succession of lobe-type feed rollers between which the portions (exiting from the forming roll 96 of the forming unit 92) are passed 97, thereby mixing and homogenizing them together before being forced between a pair of rolling rolls 108, which are configured to form a continuous strip having a thickness of about 1-20 mm, preferably about 1-10 mm.

[0059] Advantageously, the lobe feeder 102 thus causes homogenization of the product exiting the forming unit 92 and which may have lumps. Advantageously, the lobe feeder 102 further feeds the product into the pair of lobe feeders 102. Rolling Mill Move it forward to push it into the entrance to Room 108.

[0060] Therefore, the first rolling The unit 100 conveniently includes an equalization module, preferably defined by the lobe feeder 102 described above, which includes a rolling It is located immediately upstream of the module and rolling The module consists of at least one pair of Rolling Mill 108, and at least one pair of Rolling mill roll 108 is configured to form a continuous strip having a thickness of approximately 1-20 mm, preferably about 1-10 mm. Advantageously, the strip thus obtained has greater elasticity.

[0061] Conveniently, in a not shown version of the device, the rolling line 116 can be provided directly downstream of the lobe feeder 102. More specifically, in this case, the rolling line receives a continuous strip of material having a thickness of about 1 to 20 mm, preferably about 1 to 10 mm, which material side is fed by the first rolling line 116 provided with the lobe feeder 102. rolling Exit from unit 100. Advantageously, the first rolling Downstream of Unit 100 and below rollingUpstream of the line 116, a lamination unit 110 can be provided. Preferably, the lamination unit 110 is configured to arrange on several layers a continuous strip of a single layer having a thickness of about 1-10 mm, which strip leaves the first rolling unit 100, whereby the strip is transformed into a multi-layer belt having a thickness of about 2-20 mm, which multi-layer belt is then fed to the inlet of the rolling line 116.

[0062] Preferably, the layering unit 110 consists of an upstream conveyor belt 112, which serves to lay the product belt on a lower downstream conveyor belt 114, preferably associated with the rolling line 116, and which arranges the product belt to be layered on the downstream conveyor belt 114, for example by multiple folding on itself. Preferably, the upstream conveyor belt 112 is elevated with respect to the downstream conveyor belt 114, and is provided with a forward movement relative to its support structure and at the same time with a continuous movement of alternating movement with its support structure parallel to its longitudinal axis.

[0063] Conveniently, the lamination unit 110 feeds the subsequent lower layer rolling line 116, and depending on the type of equipment, the upstream conveyor belt 112 of the lamination unit 110 can be arranged parallel or perpendicular to the rolling line 116. More specifically, if the downstream conveyor 114 of the rolling line 116 has a width substantially equal to the width of the product belt leaving the layering unit 110, the upstream conveyor belt 112 is arranged parallel to the downstream conveyor belt 114 of the line 116 (Figure 1), whereas if the downstream conveyor 114 of the rolling line 116 is wider than the product belt present in the lamination unit 110, the upstream conveyor belt 112 is preferably arranged perpendicular to the downstream conveyor belt 114 of the rolling line 116 (Figure 8). This action allows the product strips to be spread over the entire useful width of the rolling line 116.

[0064] Conveniently, in either case, the alternating movement of the support structure of the upstream conveyor belt 112 of the lamination unit 110 results in stratification of the product belt emerging from the first rolling unit 100 onto the underlying first downstream conveyor belt 114 of the rolling line 116 therebelow, and the formation of a stratified belt having a width substantially equal to the useful width of the rolling line itself.

[0065] The rolling line 116 is formed of several rolling stations, each of which includes a pair of cylinders 118, which define narrow paths between them to progressively reduce the thickness of the strips of product being processed. More specifically, the rolling line 116 is configured to progressively result in a continuous strip having a thickness of 90 to 280 μm, preferably about 140 to 200 μm.

[0066] Preferably, between each rolling station there is a conveyor belt 114, preferably having a length of about 1.5-2 m, which has the function of allowing the product to rest before going to the next rolling step.

[0067] Advantageously, the rolling lines 116 then each have a pair of calibration rolling Finished at one or more calibration stations formed by rolls 120.

[0068] rolling It is advantageously considered that the rolling line 118, and possibly the calibration roll 120, can be heated so that a drying stage can already begin during the rolling line 116. Conveniently, downstream of the rolling line 116 there is a dryer 122, preferably with air recirculation (FIG. 7), in order to bring the liquid content of said rolled strip to about 8-15%. Advantageously, the dryer 122 can be divided into two units 124, 126, which are placed in series with each other. More specifically, the upstream unit 124 is provided to carry out a first drying stage and is fitted with a steel belt, or a rolling line. 116, and a downstream unit 126 is provided to carry out a second drying stage and then a cooling stage, and is equipped internally with a network conveyor belt.

[0069] Additionally, the dryer 122 is equipped with sensors 128 at the inlet and outlet to monitor the product along its length, preferably with infrared light.

[0070] The operation of the apparatus just described for the production of conventional reconstituted tobacco (FIG. 2) is as follows.

[0071] Preferably, the tobacco waste bin is placed in a tipper 2 which tips the product onto a feeder 4 which transfers the product to a vibrating conveyor 6. Here, separation of any heavy bodies from the tobacco by-product occurs, the heavy bodies are collected in a bin 8 and the tobacco by-product is transported upwardly by airflow along a pneumatic conveying line to a cyclone 12 which separates the gas and solid product and drops the solid product onto a conveyor for transport through pneumatic line 18 to a cold mill 20.

[0072] Preferably, in the production of non-conventional types of reconstituted cigarettes (FIG. 3), the cartons are instead placed on an undressing bench 22 where individual bales of tobacco leaf containing the tobacco leaves are removed from the cartons and sent to a grinder 24 which reduces the leaves themselves to a substantially uniform size of between approximately 5-10 mm.

[0073] Conveniently, the ground product is then passed along a pneumatic conveyance 26 to a cyclone 28 where it is separated from the air and dropped onto a vibrating sieve 30 .

[0074] Here separation from the remaining fraction takes place, with the fines going directly to the cryo-mill 20 and the remaining fraction passing through a thread-levelling machine 32 before reaching a classifying chamber 34. Here, any heavy bodies are separated from the crushed leaves, which are then exposed to a metal detector 42 so that each step can be seen en masse before being sent to the cryo-mill 20.

[0075] Conveniently, if the recipe requires, shredded tobacco veins can also be sent to the same cold mill 20 that is used to produce both conventional and non-conventional reconstituted tobaccos.

[0076] In this case (Figure 4), the container containing the veins is placed on an overturner 46 which feeds the veins themselves onto a vibrating conveyor 50 for removal of any heavy bodies. The veins are then moved via pneumatic lines 52 to a pin mill 54 which shreds the veins to reduce them to a size of 5-8mm.

[0077] From here, the shredded veins, separated from the conveying air in cyclone 58, are transferred to a storage silo 60, from where different types of veins from different qualities of tobacco are selected and transferred via a screw conveyor 62 to a vein dispenser 64, which mixes the veins according to the recipe to be prepared.

[0078] The crushed and dosed veins are transferred to the cold mill 20 via pneumatic line 66 .

[0079] Advantageously, regardless of the type of reconstituted tobacco produced, and thus regardless of the type of tobacco solids introduced into the shredding unit, the end product is a ground product having an average particle size of about 20-220 μm, preferably about 80-180 μm. Preferably, the ground product obtained from the fluid bed sieve fed by the cryogenic mill 20 has an average particle size of about 20-220 μm, preferably about 80-180 μm.

[0080] Advantageously, the product thus ground is sent to a mixing and storage silo 60, from which it can be removed and transferred to a mixer 80 as required.

[0081] In addition to the ground tobacco and cellulose, and generally, the solid product from the mixing and storage silo 45, water, at least one binder and at least one substance for forming the aerosol are all introduced. Advantageously, compressed air and other additives may also be introduced, including more specifically ground cloves.

[0082] Conveniently, the whole is then mixed and mixed to a liquid (moisture) content of about 30-50%, preferably about 35-40%, by wet weight, i.e. a fairly dense consistency. mixture Form.

[0083] Preferably, the mixture thus obtained is transferred to a forming unit 92 from which a plurality of portions 97, preferably shaped like lobes, are obtained.

[0084] These portions 97 of the mixture obtained from the forming unit 92 are suitably transferred to a first rolling unit 100, which is configured to homogenize the mixture and set at the outlet a continuous strip having a thickness of about 1-20 mm, preferably approximately 1-10 mm. rolling This continuous strip from unit 100 is rolling It is either transferred directly to the line 116 or is layered by a layering unit and deposited in a layered form on the inlet belt 114 of the rolling line 116. 。

[0085] Conveniently, as mentioned above, the layering is obtained by making a continuous belt fall onto the conveyor belt 112, which is advanced with respect to its support structure moved by an alternating movement, so that it is possible to arrange the product belt in several layers on said inlet conveyor belt 114. Depending on the facility and the direction of the alternating movement and the support structure of the conveyor belt 112 immediately downstream of the stacking unit 110, the product belt is arranged in several layers parallel to the longitudinal axis of the rolling line 116 or perpendicular to it.

[0086] Conveniently, at each pass from one station to another in the rolling line 116, the product strip is fed to a power calibration roll The thickness is reduced until it reaches the desired thickness corresponding to 120, which has a significant constant value of about 90 to 280 μm, preferably about 140 to 200 μm. Advantageously, furthermore, at the exit from the rolling line 116, the strip is Rolling Mill When 118 is heated and water removal has already begun during the rolling process, it has a liquid content of less than 20% or even 15%.

[0087] The product web leaving the rolling line 116 is then dried in a dryer 122 where its liquid content is reduced to about 8-15%.

[0088] Preferably, the dryer 122 is air recirculated, which is somewhat advantageous in terms of production complexity, maximum size, and energy consumption compared to dryers traditionally used in reconstituted tobacco production facilities, since the traditional facilities process a very fluid, less stable product (slurry) as opposed to the denser, more stable product processed by the inventive facility. As a result, while facilities processing slurries require traditional irradiation and conduction dryers, the inventive facility may advantageously use a recirculating air dryer 122 with a network conveyor belt or a system combining a steel conveyor belt for the first drying stage and a net conveyor belt for the second drying stage and the cooling stage. In this way, reduced dimensions are obtained (approximately 45 m compared to over 100 m for conventional dryers) while maintaining the same performance, and lower energy consumption is obtained due to the lower amount of water removed (using approximately 1000 kg / hr steam / hour compared to over 5000 kg / hr water vapor from conventional dryers).

[0089] Conveniently, at the exit of the dryer 122, the product is expected to be wound onto reels or cut into yarns of predetermined dimensions for use in cigarette packaging.

[0090] Conveniently, in the method according to the invention, homogenization of the mixture is carried out primarily or exclusively, and in any event always, using the lobe feeder 102, and only upstream, preferably immediately upstream of a pre-rolling module which converts the homogenized mixture in a continuous strip having a thickness of about 1-20 mm, preferably about 1-10 mm, for delivery to the final rolling line 116.

[0091] More specifically, once the homogenized mixture has been converted in continuous strips having a thickness of about 1-20 mm, preferably about 1-10 mm, the latter is no longer remixed but, in strip form, is sent to the rolling line 116 and brought to the desired thickness, which is a significantly constant value of about 90-280 μm, preferably about 140-200 μm. Advantageously, the fact that the rolling line 116 receives strips at its inlet and not out-of-shape mixture guarantees a constant inflow, which increases the accuracy of the thickness of the sheet in the subsequent rolling steps, and allows the same line to be rolled to a desired thickness of about 90-280 μm, preferably about 140-200 μm. Rolling Mill 118, thereby reducing the cost and overall size of the equipment.

[0092] Conveniently, if the installation, in addition to using preparation and processing parts different from those already described, is intended to produce non-traditional types of reconstituted tobacco, it uses, instead of or in addition upstream of the casting unit 92, a cylinder refiner 130 having the task of reducing the solid components of the mixture to a particle size not exceeding 20 μm.

[0093] The refiner (FIG. 7) includes a plurality of cylinders 132 arranged adjacent to one another within a closed vessel to define corresponding grinding slots. The lower cylinder 132' is mounted on an axis outside the plane containing the axes of all the other cylinders 132 and acts as a feeder of the mixture, which is taken from the bottom of the vessel and made to stand upwards in order to pass between the lower cylinder and the one immediately above and follow between all the others. The various pairs of cylinders 132 through which the mixture passes rotate at different speeds, in the sense that the upper cylinder rotates faster than the associated lower cylinder, thus stretching the mixture during the passage between each pair of cylinders 132 and thus reducing the particle size of the mixture itself. In fact, one of the important parameters for the success of the refining process is precisely the different speeds of the various cylinders 132, on which the flow path of the total mass of the mixture passing through the grinding slots depends.

[0094] The pressure between the cylinders is controlled hydraulically.

[0095] All cylinders 132 are cooled by cold water, which circulates inside each cylinder, thus counterbalancing the heat generated by the mixture due to friction both from the movement of the cylinders and from contact with the product. The temperature of the bulk of the product is thus reduced until it reaches 25°C.

[0096] Thanks to the refiner 130 just mentioned, the frictional action exerted on the mixture by the latter cylinders 132 develops a considerable binding action of the tobacco, and more particularly of the cellulose fibers contained in the latter veins, which has the double advantage of developing the aromatic components of the product and of eliminating the need to introduce more fibers into the mixture to obtain the required binding effect.

[0097] The operation of the plant in this variant embodiment is such that the shredded leaves and shredded veins obtained from the preparation and pre-processing station are fed in proportional doses according to the recipe obtained to a cold mill 20, from which a particle size of approximately 20-220 μm, preferably 80-180 μm, is obtained.

[0098] The product is then transferred, in the manner already described, to mixer 80 where a product mixture is formed as described above.

[0099] The mixture thus obtained is then fed to a cylinder refiner 130, which has the task of reducing the particle size of the solid components of the mixture to a particle size not exceeding 20 μm. Thus, the frictional action exerted on the mixture by the cylinders 132 of the refiner 130 develops a considerable binding effect of the tobacco and, more specifically, of the cellulose fibers contained in the veins, which entails a double benefit in terms of the development, on the one hand, of the aromatic components of the product, and, on the other hand, of the need to introduce more fibers into the mixture to obtain the required binding effect.

[0100] FIG. 1 diagrammatically shows the location of refiner 130 between mixer 80 and forming unit 92, however, the present invention describes that refiner 130 can be substituted for forming unit 92, in which case the mixture leaves refiner 130 and is transferred directly to first rolling unit 100 for continuation of the process cycle according to the method already described.

Claims

1. 1. A method for producing reconstituted tobacco, comprising: the tobacco solid component is ground to a particle size of between 20 and 220 μm, preferably between 80 and 180 μm; the grinding material thus obtained is mixed with powdered cellulose, water, at least one binder and at least one material for forming an aerosol until a mixture is obtained with a liquid content of about 30-50% by weight on a wet basis, preferably about 35-40% by weight on a wet basis; - said mixture is subjected to a first rolling step in order to obtain continuous strips having a thickness of about 1 to 20 mm, preferably about 1 to 10 mm; - the strip already subjected to the first rolling step is subjected to a series of further rolling steps until a strip having a very constant thickness of approximately 90 to 280 μm, preferably approximately 140 to 200 μm, is obtained; - the strips are dried until their liquid content is about 8-15% by weight on a wet basis.

2. 2. The method of claim 1, wherein the dried continuous strip is wound or chopped into threads of predetermined dimensions.

3. 3. The method according to claim 1 or 2, characterized in that the solid component is tobacco ground by milling.

4. 4. The method according to claim 1, wherein the solid components of the tobacco are ground using a mill.

5. 5. The method according to any one of claims 1 to 4, characterized in that the solid component is tobacco ground using a cold pin mill (20).

6. The method described in any one of claims 1 to 5, characterized in that the powdered cellulose is made of organic fibers obtained from natural cellulose.

7. 7. The method according to claim 1, wherein the mixture is formed with powdered cellulose having a particle size between 50 and 100 μm.

8. A method according to any one of claims 1 to 7, characterized in that the mixture is formed using powdered cellulose in a proportion comprised between 2% and 10% by mass of the tobacco.

9. 9. The method according to any one of claims 1 to 8, characterized in that crushed cloves are added to the mixture.

10. 10. The method of claim 1, wherein ground tobacco components are mixed with powdered cellulose prior to forming the mixture therewith.

11. 11. The method according to claim 1, characterized in that the mixture formed by the grinding material, the powdered cellulose, the water, the at least one binder and the at least one material for forming an aerosol is subjected to a roughening step by passing it through at least a pair of grooved cylinders (92) and / or a purification step by passing it through at least a pair of refining cylinders (132, 132') until the particle size of the mixture reaches 20 μm.

12. 12. The method according to any one of claims 1 to 11, characterized in that the mixture undergoes a homogenization and / or shaping step before being subjected to the first rolling step.

13. 13. The method according to any one of claims 1 to 12, characterized in that the at least one binder comprises at least one of the following: hydroxypropyl cellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose, microcrystalline cellulose, methylcellulose, carboxymethyl cellulose (CMC), corn starch, potato starch, guar gum, locust bean gum, pectin, and alginates, in particular ammonium alginate and sodium alginate.

14. 14. A method according to any one of claims 1 to 13, characterized in that the mixture is subjected to a homogenization and / or shaping stage in order to be transformed into a continuous strip having a substantially constant width between 100 and 2000 mm and a thickness between 1 and 10 mm, before being subjected to the first rolling step.

15. 15. A method according to any one of claims 1 to 14, characterized in that the mixture undergoes a homogenization and / or shaping step in order to be transformed into a series of parts (97) before being subjected to the first rolling step.

16. 16. The method according to any one of claims 1 to 15, characterized in that the first rolling step of the mixture is carried out using a rolling unit (100) comprising a lobe feeder (102) and at least one pair of rolling rolls (108).

17. A method according to any one of claims 1 to 16, characterized in that the first rolling step includes a homogenization step carried out before obtaining the continuous strips having a thickness of about 1 to 20 mm, preferably about 1 to 10 mm.

18. 18. A method according to any one of the preceding claims, characterized in that the mixture is first subjected to a forming step in order to be transformed into a series of portions (97), followed in succession by a homogenization step of said portions (97) and then a step of obtaining from these said continuous strips having a thickness of about 1 to 20 mm, preferably about 1 to 10 mm.

19. 19. The method according to any one of claims 1 to 18, characterized in that the mixture is homogenized mainly or exclusively by means of a lobe feeder (102) placed at the inlet of at least one pair of mill rolls (108).

20. 20. A method according to any one of the preceding claims, characterized in that a monolayer tape having a thickness of about 1 to 10 mm is obtained at the outlet of the first rolling step.

21. A method according to any one of claims 1 to 20, characterized in that prior to the series of further rolling steps, the strips already subjected to the first rolling step are subjected to layering until a multi-layer strip having a thickness of approximately 2 to 20 mm is obtained.

22. A method according to any one of claims 1 to 21, characterized in that in the series of further rolling steps, the mixture is placed between one rolling station and the next rolling station.

23. 23. The method according to any one of claims 1 to 22, characterized in that the series of further rolling steps is carried out with at least partially heated mating rolls (118).

24. 24. The method according to any one of claims 1 to 23, characterized in that the strips that have been subjected to the series of further rolling steps are dried in order to pass through a dry air recirculation system (122).

25. 1. An apparatus for the production of reconstituted tobacco, comprising: a grinding unit (20, 24, 54) for the solid components of tobacco to a particle size of about 20 to 220 μm, preferably 80 to 180 μm; a mixer (80) configured to receive measured amounts of shredded material, powdered cellulose, water, at least one binder, and at least one material for forming an aerosol and to obtain a mixture with a liquid content of about 30-50% by weight on a wet basis, preferably about 35-40% by weight on a wet basis; - a first rolling unit (100) for obtaining from said mixture continuous strips having a thickness of about 1 to 20 mm, preferably about 1 to 10 mm; - a rolling line (116) arranged downstream of said first rolling unit (100) for bringing said continuous strip to a thickness of between 90 and 280 μm, preferably between 140 and 200 μm; a dryer (122) for bringing the liquid content of the continuous strip to about 8-15% by weight on a wet basis.

26. 26. The installation according to claim 25, characterized in that the dryer provides air circulation.

27. 27. Installation according to claim 25 or 26, characterized in that the grinding unit comprises a mill (20).

28. 28. Installation according to any one of claims 25 to 27, characterized in that the grinding unit comprises a cryogenic pin mill.

29. 29. Installation according to any one of claims 25 to 28, characterized in that it comprises means for feeding cellulose in powder form to the mixer.

30. 28. The installation according to claim 27, characterized in that it comprises at least one silo (45) upstream of the mill (20) for mixing and storing solid materials comprising ground tobacco components and the powdered cellulose.

31. 31. The installation according to any one of claims 25 to 30, characterized in that it comprises a mixture-forming unit (92) downstream of the mixer (80) and upstream of the first rolling unit (100).

32. 32. Installation according to claim 31, characterized in that the mixture-forming unit (92) is also configured to homogenize the mixture.

33. Installation according to claim 31 or 32, characterized in that the mixture forming unit (92) is configured to transform the mixture into a continuous belt having a substantially constant width between 100 and 2000 mm and a thickness between 1 and 4 mm.

34. 34. The installation according to any one of claims 31 to 33, characterized in that the mixture forming unit (92) is configured to divide the mixture into a plurality of portions (97) to be fed to the first rolling unit (100).

35. 35. Installation according to any one of claims 31 to 34, characterized in that the mixture-forming unit (92) comprises a roughening machine equipped with at least a pair of grooved cylinders (96) and / or a refiner having a cylinder (130).

36. 36. The installation according to any one of claims 25 to 35, characterized in that the first rolling unit (100) comprises a pre-rolling module and a mixture homogenization module located immediately upstream with respect to the pre-rolling module, the pre-rolling module being defined by at least a pair of rolling rolls (108), the rolling rolls being configured to form a continuous strip having a thickness of about 1 to 20 mm, preferably about 1 to 10 mm.

37. 37. The installation of claim 36, wherein the homogenization module includes a lobe feeder (102).

38. 38. The installation according to any one of claims 25 to 37, characterized in that the first rolling unit (100) comprises a lobe feeder (102) and at least a pair of rolling rolls (108).

39. 39. Installation according to any one of claims 25 to 38, characterized in that it comprises a lamination unit (110) downstream of the first rolling unit (100).

40. The equipment described in claim 39, characterized in that the stacking unit (110) includes an upstream conveyor belt (112) supplied by the first rolling unit (100) and having continuous motion relative to one of the support structures, the continuous motion being provided together with alternating motion relative to a lower layer downstream conveyor belt (114).

41. 41. Installation according to any one of claims 25 to 40, characterized in that the rolling line (116) comprises a plurality of rolling stations separated from one another by sections of a conveyor belt (114) of sufficient length to allow the placement of the continuous strip between one rolling station and the next.

42. 42. Installation according to any one of claims 25 to 41, characterized in that the rolling line (116) is formed from a plurality of rolling stations, each of which comprises a pair of rolling rolls, at least some of the rolling rolls (118, 120) being heated.

43. An installation as described in any one of claims 25 to 42, wherein the dryer (122) comprises a first unit (124) in which a first drying step is performed on the continuous strip leaving the rolling line (116) and a second unit (126) arranged in series with the first unit, in which a second drying stage is performed, followed by a cooling stage of the already partially dried continuous strip resulting from the first unit (124).

44. An installation as described in any one of claims 25 to 43, characterized in that at least one mesh conveyor is used inside the dryer (122).

45. 45. Installation according to claim 43 or claim 44 when dependent on claim 43, characterized in that the dryer (122) comprises a steel belt or a net conveyor belt inside the first unit (124) and a network conveyor belt inside the second unit (126).

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