Homogenized tobacco material production line and method for inline production of homogenized tobacco material
10834956 ยท 2020-11-17
Assignee
Inventors
Cpc classification
A24B15/167
HUMAN NECESSITIES
A24B3/14
HUMAN NECESSITIES
A24B15/14
HUMAN NECESSITIES
B65H2220/01
PERFORMING OPERATIONS; TRANSPORTING
B65H2220/01
PERFORMING OPERATIONS; TRANSPORTING
B65H2511/14
PERFORMING OPERATIONS; TRANSPORTING
B65H19/26
PERFORMING OPERATIONS; TRANSPORTING
B65H2511/14
PERFORMING OPERATIONS; TRANSPORTING
B65H18/106
PERFORMING OPERATIONS; TRANSPORTING
International classification
A24B3/14
HUMAN NECESSITIES
B65H35/02
PERFORMING OPERATIONS; TRANSPORTING
A24B15/14
HUMAN NECESSITIES
B65H19/26
PERFORMING OPERATIONS; TRANSPORTING
A24B15/167
HUMAN NECESSITIES
B65H18/10
PERFORMING OPERATIONS; TRANSPORTING
Abstract
The invention relates to a homogenized tobacco sheet production line comprising: A tank (501) adapted to contain a slurry formed by a tobacco powder blend, a binder and an aerosol former in an aqueous medium; A cast apparatus (600) adapted to receive slurry from the tank and to cast the slurry so as to form a homogenized tobacco material; A movable transporting support (606) on which said slurry is casted and adapted to transport the homogenized tobacco material along a transport direction; A slitter (611) located downstream the cast apparatus adapted to slit the homogenized tobacco material along the transport direction so as to form portioned homogenized tobacco sheets; and A winding station (613) located downstream the slitter adapted to receive the portioned homogenized tobacco sheets from the slitter and to wind at least one of the portioned homogenized tobacco sheets in a bobbin. It also relates to a method for inline production of a homogenized tobacco sheet.
Claims
1. A homogenized tobacco sheet production line comprising: a tank adapted to contain a slurry formed by a tobacco powder blend, a binder and an aerosol former in an aqueous medium; a cast apparatus adapted to receive slurry from the tank and to cast the slurry so as to form a homogenized tobacco material; a movable transporting support on which said slurry is casted and adapted to transport the homogenized tobacco material along a transport direction; a slitter located downstream the cast apparatus adapted to slit the homogenized tobacco material along the transport direction so as to form portioned homogenized tobacco sheets, wherein the said slitter comprises at least two blades, so as to form at least three portioned homogenized tobacco sheets; and a winding station located downstream the slitter adapted to receive the portioned homogenized tobacco sheets from the slitter and to wind at least one of the portioned homogenized tobacco sheets in a bobbin, wherein the winding station comprises a number of bobbin holders equal to the number of portioned homogenized tobacco sheets in which the homogenized tobacco sheet is cut by the slitter, wherein the winding station includes: a sensor adapted to detect a size of the bobbin or an amount of portioned homogenized tobacco sheet wound in the bobbin and to send a signal if the size or amount exceeds a given threshold; and a wound bobbin cutting element, to automatically transversally cut the portioned homogenized tobacco sheet in the bobbin so that the bobbin can be exchanged in response to the sensor signal.
2. The homogenized tobacco sheet production line according to claim 1, comprising: a drying station located downstream the cast apparatus and upstream said slitter adapted to dry the homogenized tobacco sheet.
3. The homogenized tobacco sheet production line according to claim 2, wherein the slitter is located directly downstream the drying station.
4. The homogenized tobacco sheet production line according to claim 1, wherein the winding station is located directly downstream the slitter.
5. The homogenized tobacco sheet production line according to claim 1, wherein the movable transporting support includes a single continuous moving support transporting said homogenized tobacco sheet from the cast apparatus to the slitter.
6. A method for inline production of homogenized tobacco material, said method comprising: preparing a slurry comprising tobacco powder blend, a binder and an aerosol former in an aqueous medium; casting the slurry in a support movable along a transport direction to form a homogenized tobacco sheet; slitting the homogenized tobacco sheet along said transport direction in at least three portioned homogenized tobacco sheets while the homogenized tobacco sheet is moved along the transport direction so as to form portioned homogenized tobacco sheets; winding each portioned homogenized tobacco sheet in a bobbin; checking an amount of portioned homogenized tobacco sheet wound in the bobbin or a size of the bobbin; and automatically changing the bobbin if said amount or said size is above a given threshold.
7. The method according to claim 6, including: drying the portioned homogenized tobacco sheet.
8. The method according to claim 6, wherein the step of preparing a slurry comprises: suspending a binder in an aerosol-former to form a suspension; creating a cellulose pulp from cellulose fibers and water; providing a tobacco powder blend; and combining the suspension of binder in aerosol-former, the cellulose pulp and the tobacco powder blend to form the slurry.
9. The method according to claim 6, wherein the step of preparing a slurry comprises: pulping and refining cellulose fibres to obtain fibres having a mean size comprised between about 0.2 millimetres and about 4 millimetres; grinding a blend of tobacco of one or more tobacco types to a tobacco powder having a mean size comprised between about 0.03 millimetres and about 0.12 millimetres; combining the pulp with the tobacco powder blend of different tobacco types and with a binder in an amount comprised between about 1 percent and about 5 percent in dry weight basis of the total weight of the homogenized tobacco material, so as to form a slurry; and homogenizing the slurry.
Description
(1) Specific embodiments will be further described, by way of example only, with reference to the accompanying drawings in which:
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(10) With initial reference to
(11) Only the selected tobacco types and tobacco grades intended to be production of the used for the homogenized tobacco material undergo the processing according to following steps of the method of the invention.
(12) The method includes a further step 101 in which the selected tobacco is laid down. This step may comprise checking the tobacco integrity, such as grade and quantity, which can be for example verified by a bar code reader for product tracking and traceability. After harvesting and curing, the leaf of tobacco is given a grade, which describes for example the stalk position, quality, and colour.
(13) Further, the lay down step 101 might also include, in case the tobacco is shipped to the manufacturing premises for the production of the homogenized tobacco material, de-boxing or case opening of the tobacco boxes. The de-boxed tobacco is then preferably fed to a weighing station in order to weight the same.
(14) Moreover, the tobacco lay down step 101 may include bale slicing, if needed, as the tobacco leaves are normally compressed into bales in shipping boxes for shipping.
(15) The following steps are performed for each tobacco type, as detailed below. These steps may be performed subsequently per grade such that only one production line is required. Alternatively, the different tobacco types may be processed in separate lines. This may be advantageous where the processing steps for some of the tobacco types are different. For example, in conventional primary tobacco processes bright tobaccos and dark tobaccos are processed at least partially in separate processes, as the dark tobacco often receives an additional casing. However, according to the present invention, preferably, no casing is added to the blended tobacco powder before formation of the homogenized tobacco web.
(16) Further, the method of the invention includes a step 102 of coarse grinding of the tobacco leaves.
(17) According to a variant of the method of the invention, after the tobacco lay down step 101 and before the tobacco coarse grinding step 102, a further shredding step 103 is performed, as depicted in
(18) Preferably, after the shredding step 103, a step of removal of non-tobacco material from the strips is performed (not depicted in
(19) Subsequently, the shredded tobacco is transported towards the coarse grinding step 102. The flow rate of tobacco into a mill to coarse grind the strips of tobacco leaf is preferably controlled and measured.
(20) In the coarse grinding step 102, the tobacco strips are reduced to a mean particle size of between about 0.25 millimetres and about 2 millimetres. At this stage, the tobacco particles are still with their cells substantially intact and the resulting particles do not pose relevant transport issues.
(21) Preferably, after the coarse grinding step 102, the tobacco particles are transported, for example by pneumatic transfer, to a blending step 104. Alternatively, the step of blending 104 could be performed before the step of coarse grinding 102, or where present, before the step of shredding 103, or, alternatively, between the step of shredding 103 and the step of coarse grinding 102.
(22) In the blending step 104, all the coarse grinded tobacco particles of the different tobacco types selected for the tobacco blend are blended. The blending step 104 therefore is a single step for all the selected tobacco types. This means that after the step of blending there is only need for a single process line for all of the different tobacco types.
(23) In the blending step 104, preferably mixing of the various tobacco types in particles is performed. Preferably a step of measuring and controlling one or more of the properties of the tobacco blend is performed. According to the invention, the flow of tobacco may be controlled such that the desired blend according to a pre-set target value or pre-set target values is obtained. For example, it may be desirable that the blend includes bright tobacco 1 at least for about 30 percent in dry weight of the total tobacco in the blend, and that dark tobacco 2 and aromatic tobacco 3 are comprised each in a percentage between about 0 percent and about 40 percent in dry weight basis of the total tobacco in the blend, for example about 35 percent. More preferably, also filler tobacco 4 is introduced in a percentage between about 0 percent and about 20 percent in dry weight basis of the total tobacco in the blend. The flow rate of the different tobacco types is therefore controlled so that this ratio of the various tobacco types is obtained. Alternatively, where the coarse grinding step 102 is done subsequently for the different tobacco leafs used, the weighing step at the beginning of the step 102 determines the amount of tobacco used per tobacco type and grade instead of controlling its flow rate.
(24) In
(25) It is to be understood that each tobacco type could be itself a sub-blend, in other words, the bright tobacco type could be for example a blend of Virginia tobacco and Brazil flue-cured tobacco of different grades.
(26) After the blending step 104, a fine grinding step 105, to a tobacco powder mean size of between about 0.03 millimetres and about 0.12 millimetres is performed. This fine grinding step 105 reduces the size of the tobacco down to a powder size suitable for the slurry preparation. After this fine grinding step 105, the cells of the tobacco are at least partially destroyed and the tobacco powder may become sticky.
(27) The so obtained tobacco powder can be immediately used to form the tobacco slurry. Alternatively, a further step of storage of the tobacco powder, for example in suitable containers may be inserted (not shown).
(28) The steps of tobacco blending and grinding tobacco for the formation of a homogenized tobacco material according to
(29) In
(30) Mill 204 is adapted to coarse grind the tobacco strips up to a size of between about 0.25 millimetres and about 2 millimetres. The rotor speed of the mill can be controlled and changed on the basis of the tobacco shreds flow rate.
(31) Preferably, a buffer silo 206 for uniform mass flow control, is located after the coarse grinder mill 204. Furthermore, preferably mill 204 is equipped with spark detectors and safety shut down system 207 for safety reasons.
(32) From the mill 204, the tobacco particles are transported, for example by means of a pneumatic transport 208, to a blender 210. Blender 210 preferably includes a silo in which an appropriate valve control system is present. In the blender, all tobacco particles of all the different types of tobacco which have been selected for the predetermined blend are introduced. In the blender 210, the tobacco particles are mixed to a uniform blend. From the blender 210, the blend of tobacco particles is transported to a fine grinding station 211.
(33) Fine grinding station 211 is for example an impact classifying mill with suitable designed ancillary equipment to produce fine tobacco powder to the right specifications, that is, to a tobacco powder between about 0.03 millimetres and about 0.12 millimetres. After the fine grinding station 211, a pneumatic transfer line 212 is adapted to transporting the fine tobacco powder to a buffer powder silo 213 for continuous feed to a downstream slurry batch mixing tank where the slurry preparation process takes place.
(34) The method for the production of a homogenized tobacco material of
(35) The step of forming a suspension 106 of binder in aerosol-former includes the steps of loading the aerosol-former 5 and the binder 6 in a container and mixing the two. Preferably, the resulting suspension is then stored before being introduced in the slurry. Preferably, the glycerol is added to the guar in two steps, a first amount of glycerol is mixed with guar and a second amount of glycerol is then injected in the transport pipes, so that glycerol is used to clean the processing line, avoiding hard-to-clean points within the line.
(36) A slurry preparation line 300 adapted to perform the suspension of binder in aerosol-former as per step 106 of the invention is depicted in
(37) The slurry preparation line 300 includes an aerosol-former, such as glycerol, bulk tank 301 and a pipe transfer system 302 having a mass flow control system 303 adapted to transfer the aerosol-former 5 from the tank 301 and to control its flow rate. Further, the slurry preparation line 300 comprises a binder handling station 304 and a pneumatic transport and dosing system 305 to transport and weight the binder 6 received at the station 304.
(38) Aerosol-former 5 and binder 6 from tank 301 and handling station 304, respectively, are transported to a mixing tank, or more than a mixing tank, 306, part of the slurry preparation line 300, designed to mix binder 6 and aerosol-former 5 uniformly.
(39) The method to realize the homogenized tobacco material includes a step of preparing a cellulose pulp 107. The pulp preparation step 107 preferably comprises mixing cellulose fibres 7 and water 8 in a concentrated form, optionally storing the pulp so obtained and then diluting the concentrated pulp before forming the slurry. The cellulose fibres, for example in boards or bags, are loaded in a pulper and then liquefied with water. The resulting water-cellulose solution may be stored at different densities, however preferably the pulp which is the result of the step 107 is concentrate. Preferably, concentrate means that the total amount in the cellulose fibres in the pulp is between about 3 percent and 5 percent of the total pulp weight before dilution. Preferred cellulose fibres are soft wood fibres. Preferably, the total amount of cellulose fibres in the slurry in dry weight is between about 1 percent and about 3 percent, preferably, between about 1.2 percent and about 2.4 percent in dry weight of the slurry.
(40) Preferably, the step of mixing of water and cellulose fibres lasts between about 20 and about 60 minutes, advantageously at a temperature comprised between about 15 degrees Celsius and about 40 degrees Celsius.
(41) The storage time, if storage of the pulp is performed, may preferably vary between about 0.1 day and about 7 days.
(42) Advantageously, water dilution takes place after the step of storing of the concentrated pulp. Water is added to the concentrated pulp in such an amount that the cellulose fibres are less than about 1 percent of the total weight of the pulp. For example a dilution of a factor comprised between about 3 and about 20 can take place.
(43) Further, an additional step of mixing may take place, which comprises mixing the concentrated pulp and the added water. The additional mixing step preferably lasts between about 120 minutes and about 180 minutes at a temperature between about 15 degrees Celsius and about 40 degrees Celsius, more preferably at a temperature of between about 18 degrees Celsius and about 25 degrees Celsius.
(44) All tanks and transfer pipes for cellulose fiber, guar and glycerol are preferably designed to be as optimally short as possible to reduce transfer time, minimize waste, avoid cross contamination and facilitate ease of cleaning. Further, preferably, the transfer pipes for cellulose fiber, guar and glycerol are as straight as possible, to allow a swift and uninterrupted flow. In particular for the suspension of binder in the aerosol-former, turns in the transfer pipe could otherwise result in areas of low flow rate or even standstill, which in turn can be areas where gelling can occur and with that potentially blockages within the transfer pipes. As mentioned before, those blockages can lead to the need for cleaning and standstill of the entire manufacturing process.
(45) Preferably, after the step of pulp preparation 107, an optional step of fibres' fibrillation is performed (not depicted in
(46) An apparatus 400 to perform the method step 107 of the pulp formation is depicted in
(47) The pulper 402 includes a temperature control unit 401a so that the temperature in the pulper is kept within a given temperature interval, and a rotational speed control unit 401b, so that the speed of an impeller (not shown) present in the pulper 402 is controlled and kept preferably comprised between about 5 rpm and about 35 rpm.
(48) The cellulose fibre feeding and preparation line 400 further comprises a water line 404 adapted to introduce water 8 in the pulper 402. A flow rate controller 405 to control the flow rate of water introduced in pulper 402 is preferably added in the water line 404.
(49) The cellulose fibre feeding and preparation line 400 may also further comprise a fibre refiner system 403 to treat and fibrillate fibres, so that long fibres and nested fibres are removed, and a uniform fibre distribution is obtained.
(50) Preferably, the mean size of the cellulose fibres at the end of the pulping and refining step is comprised between about 0.2 millimetres and about 4 millimetres, more preferably between about 1 millimetre and about 3 millimetres.
(51) The mean size is considered to be the mean length. Each length of the fibre is calculated following the framework of the fibre, therefore it is the real developed length of the fibre. The mean fibre length is calculated per number of fibres, for example it may be calculated on 5.000 fibers.
(52) Measured objects are considered as fibres if their length and width are comprised within:
200 m<length<10.000 m
5 m<width<75 m
(53) In order to calculate the mean fibre length, the MorFi Compact fibre analyzer on fibers produced by Tech Pap SAS can be used.
(54) The analysis is performed for example putting the fibres in a solution, so as to form an aqueous fibrous suspension. Preferably, deionized water is used and no mechanical mixing is applied during sample preparation. Mixing is performed by the fibre analyzer. Preferably, measurements are performed on fibres which have stayed at least 24 hours at about 22 degrees Celsius and about 50 percent relative humidity.
(55) Downstream the fibre refiner system 403, the cellulose fibre feeding and preparation line 400 may comprise a cellulose buffer tank 407 connected to the fibre refiner system 403 to store the high consistency fibre solution coming out of the system 403.
(56) At the end of cellulose fibre feeding and preparation line 400, a cellulose dilution tank 408 in which pulp is diluted is preferably present and connected to cellulose buffer tank 407. The cellulose dilution tank 408 is adapted to batch out cellulose fibres of right consistency for subsequent slurry mixing. Water for dilution is introduced in tank 408 via a second water line 410.
(57) The method to form a slurry according to the invention further comprises a step of slurry formation 108, where the suspension 9 of binder in aerosol-former obtained in step 106, the pulp 10 obtained in step 107 and the tobacco powder blend 11 obtained in step 104 are combined together.
(58) Preferably, the step of slurry formation 108 comprises first a step of introduction in a tank of the suspension 9 of binder in aerosol-former and of the cellulose pulp 10. Afterwards, the tobacco powder blend 11 is introduced as well. Preferably, the suspension 9, the pulp 10 and the tobacco powder blend 11 are suitably dosed in order to control the amount of each of them introduced in the tank. The slurry is prepared according to specific proportion among its ingredients. Optionally, also water 8 is added as well.
(59) Preferably, the step of slurry formation 108 also comprises a mixing step, where all the slurry ingredients are mixed together for a fixed amount of time. In a further step of the method according to the invention, the slurry is then transferred to a following casting step 109 and drying step 110.
(60) An apparatus 500 for the slurry formation adapted to realize step 108 of the method of the invention is schematically depicted in
(61) For example, the tobacco powder blend 11 may be contained in a tobacco fine powder buffer storage silo to ensure continuous upstream powder operation and meeting demand of slurry mixing process. Tobacco powder is transferred to the mixing tank 501 preferably by means of a pneumatic transfer system (not shown).
(62) The apparatus 500 further comprises preferably a powder dosing/weighing system (also not shown) to dose required amount of the slurry's ingredients. For example, the tobacco powder may be weighted by a scale (not shown) or weighting belt (not shown) for precise dosing. The mixing tank 501 is specially designed to mix the dry and liquid ingredients to form a homogenous slurry. The slurry mixing tank preferably comprises a cooler (not shown), such as water jacket wall to allow water cooled on the external walls of the mixing tank 501. The slurry mixing tank 501 is further equipped with one or more sensors (not shown) such as a level sensor, a temperature probe and a sampling port for control and monitoring purpose. Mixing tank 501 has an impeller 502 adapted to ensure uniform mixing of the slurry, in particular adapted to transfer slurry form the external walls of the tank to the internal part of the tank or vice-versa. The speed of the impeller can be preferably controlled by means of a dedicated controlling unit. Mixing tank 501 also includes a water line for the introduction of water 8 at a controlled flow rate.
(63) Preferably, mixing tank 501 includes two separated tanks, one downstream to the other in the flow of slurry, one tank for preparing the slurry and the second tank with slurry for transfer to provide continuous slurry supply to a casting station.
(64) The method of the invention to produce a homogenized tobacco web includes further a casting step 109 in which the slurry prepared in step 108 is cast in a continuous tobacco web onto a support. The casting step 109 includes transferring the slurry from the mixing tank 501 to a casting box. Further, it preferably includes monitoring the level of slurry in the casting box and the moisture of the slurry. Then, the casting step 109 includes casting, preferably by means of a casting blade, the slurry onto a support, such as a steel conveyor. Further, in order to obtain a final homogenized tobacco web for the use in an aerosol-formed article, the method of the invention includes a drying step 110 in which the cast web of homogenized tobacco material is preferably dried. The drying step 110 includes drying the cast web, by means of steam and heated air. Preferably the drying with steam is performed on the side of the cast web in contact with the support, while the drying with heated air is performed on the free side of the cast web.
(65) An apparatus for performing the steps of casting 109 and drying 110 is schematically depicted in
(66) A support, such as a stainless steel belt conveyor 606, receives the slurry cast by the casting blade 604. The width of the slurry at casting forming a cast web is of about 1.93 meters.
(67) Casting and drying apparatus 600 also includes a drying station 608 to dry the cast web of slurry. Drying station 608 comprises a steam heating 609 and top air drying 610.
(68) The cast web goes preferably through a secondary drying process to remove further moisture content of the web to reach moisture target or specification. The width of the cast web after drying is preferably of about 1.8 meters.
(69) After the drying step 110, the cast web is preferably cut in one or more portioned homogenized tobacco sheets in a slitting step 111, for example to form three portioned parallel webs 612, as shown in
(70) Preferably, the width of the portioned cast webs 612 after slitting is comprised between about 0.05 meters and about 0.5 meters, more preferably the width is of about 0.125 meters.
(71) After the slitting step 111, the portioned webs 612 are each wound in a bobbin, in a winding step 112 which takes place at a winding station 613. Each portioned web 612 is preferably wound in a different bobbin, such as the three bobbins 614 shown in
(72) The bobbins 614 may then be used for the production of an aerosol-generating article (not shown).