Method and apparatus for drying strips of adhesive material for the manufacture of smoking products

Abstract

A method for drying a strip (6) of a paste-like material for the manufacture of smoking products, comprising the steps of supplying the strip (6) of the paste-like material to a drying chamber (2), and transporting the strip (6) of the paste-like material in the drying chamber between an infeed station (22) and an outfeed station in the drying chamber (2). In particular, the transport step involves rolling the strip of the paste-like material on a plurality of transport surfaces that are continuously arranged along a first transport path extending between the infeed station and the outfeed station.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for drying an elongated strip of a paste-like material for the manufacture of smoking articles.

[0002] Explicitly, this specification relates to a paste-like material including tobacco or a product derived therefrom, and more generally, in the context of smoking articles such as tobacco, to substances capable of generating an aerosol.

Background Art

[0003] International Publication No. 2020 / 058814 describes obtaining a continuous strip of reconstituted tobacco, which is rolled or cut into filamentous strips of a predetermined size and appropriately mixed with each other before being supplied to a conventional tobacco manufacturing machine.

[0004] More generally, the continuous strip from which the strips are obtained is made using tobacco by-products and processing waste (midribs, leaf fragments, dust, etc.). These by-products are appropriately pulverized until they are substantially in powder form and, when mixed with water, glycerin binder and other liquid additives, a mixture with a water content of about 30% to 50%, preferably 35% to 40% can be obtained, and then processed to obtain a strip of substantially constant thickness, for example, 90 to 280 μm, preferably about 100 to 140 μm. This strip is then dried until it reaches the required water content, generally about 7% to 15%, and is used to obtain a product that can be immediately processed, particularly by cutting, or stored on a roll for use at a later stage.

[0005] The drying of the strip is an important part of the process. This is because the product is still soft due to its high water content and can be quickly dried by placing it in a drying chamber on a mesh conveyor and flowing hot air on both sides. On the other hand, since the product is still soft and easily deformed, the trace of the mesh remains on the product.

[0006] This problem can be avoided by using steel belt conveyors instead of mesh conveyors. Steel belts are smooth and do not leave marks on stripped products, even if the product is very wet. However, this not only increases installation and running costs, but also increases drying time because air cannot be blown onto the underside of the stripped products, the large equipment occupies a lot of floor space in the factory, and energy consumption is also high.

[0007] To find a compromise between these two conflicting needs, a two-stage dryer has been proposed. The first stage (main dryer) consists of a steel belt and leaves no marks on the stripped product, resulting in a moisture content higher than the final required value, but significantly reducing the product's plasticity and deformability. The product is then transferred to the second stage (mesh dryer), where it is placed on a mesh conveyor, allowing the moisture content to be reduced to the required final level without leaving any marks.

[0008] However, this solution also requires the use of a steel belt conveyor, which makes the structure quite complex and costly, and since it actually consists of two separate dryers, it also consumes a lot of energy. [Overview of the project]

[0009] The object of the present invention is to propose a method and apparatus for drying strips of the above-described type of adhesive material without causing the drawbacks of prior art methods and equipment.

[0010] In particular, the present invention aims to propose a method and apparatus that can further reduce the size of a dryer, making it substantially equivalent to a conventional mesh dryer.

[0011] Another object of the present invention is to propose a method and apparatus that can significantly reduce energy consumption compared to conventional dryers having the same performance.

[0012] Another object of the present invention is to propose a method and apparatus that can lower installation and running costs compared to conventional drying ovens with the same performance.

[0013] All of the above objectives and other objectives evident from the following description are achieved, depending on the size, by a method and apparatus for drying strips of adhesive material for the manufacture of smoking articles as described in the attached claims.

[0014] In particular, in one aspect, the present invention is a method for drying strips of a paste-like material for the manufacture of smoking products, A process of supplying strips of adhesive material to a drying chamber, The present invention provides a method comprising the step of transporting a strip of adhesive material in a drying chamber between an infeed station and an outfeed station of the drying chamber. In particular, the transport step involves rolling the strip of adhesive material on a plurality of transport surfaces that are continuously arranged along a first transport path extending between the infeed station and the outfeed station.

[0015] An advantage of this process is that it prevents marks from being left on the material strip, which can occur, for example, on a mesh surface.

[0016] In a further aspect of the present invention, the conveying process includes a preliminary step in which the first portion, or end, of the strip is drawn out at an infeed station and transported to an outfeed station along a second conveying path different from the first conveying path. This preliminary step may be fully automated or performed manually or semi-manually, as detailed below.

[0017] In a further aspect of the present invention, during the above preliminary step, the first portion of the strip is placed on at least one support / retraction surface and transported by the support / retraction surface from the infeed station to the outfeed station along a second transport path.

[0018] In a further aspect of the present invention, the first transport path runs linearly between the infeed station and the outfeed station of the drying chamber. This embodiment ensures a high level of simplification of structure and operation.

[0019] In a further aspect of the present invention, the first conveying path runs in a zigzag pattern between the infeed station and the outfeed station of the drying chamber. This configuration allows for the drying of longer strips within the same footprint compared to a linear first conveying path.

[0020] In a further aspect of the present invention, the second transport path runs above the first transport path, across the first transport path. This embodiment ensures a high level of simplification of structure and operation.

[0021] In a further aspect of the present invention, the first and second transport paths are parallel.

[0022] In a further aspect of the present invention, the steps of supplying a strip of adhesive material to a drying chamber and transporting the strip within the drying chamber are coordinated to impart the same longitudinal supply speed to the strip. An advantage of this embodiment is that the supplied strip of material is not damaged and / or subjected to undesirable stresses that could alter its shape and / or cause it to tear.

[0023] In other respects, the present invention relates to an apparatus for drying strips of paste-like material for the manufacture of smoking products, Drying room and A supply means for supplying strips of adhesive material to a drying chamber, The present invention provides a device comprising a conveying means for transporting strips of adhesive material in a drying chamber between an infeed station and an outfeed station in the drying chamber.

[0024] In particular, the conveying means includes a plurality of conveying surfaces that are continuously arranged along a first conveying path extending between the infeed station and the outfeed station of the drying chamber, and that convey the strip of the paste-like material in a rolling transfer manner.

[0025] As an advantage, the plurality of conveying surfaces that perform rolling transfer of the strip can prevent the strip of the material from being marked, such as may occur on a mesh surface.

[0026] In a further aspect of the present invention, the first conveying path runs linearly between the infeed station and the outfeed station of the drying chamber. This aspect enables reliable simplification of the structure and operation at a high level.

[0027] In a further aspect of the present invention, the first conveying path runs in a zigzag manner between the infeed station and the outfeed station of the drying chamber. This aspect enables drying of a longer strip compared to the case where the first conveying path is linear in an apparatus with the same installation area.

[0028] In a further aspect of the present invention, the conveying means includes a roller conveyor having a plurality of rollers that form a plurality of conveying surfaces that are continuously arranged along the first conveying path, and at least one of which is motorized.

[0029] As an advantage, by providing a conveyor having motorized rollers, the strip can be rolled without being rubbed, and damage to the strip can be prevented.

[0030] In a further aspect of the present invention, the supply means for supplying the strip of the paste-like material to the drying chamber and the conveying means for conveying the strip of the paste-like material in the drying chamber are linked to each other so as to give the strip the same longitudinal supply speed. As an advantage, this aspect enables the strip of the supplied material to be free from damage and / or to be free from stress that may cause damage by changing its shape and / or tearing.

[0031] In a further aspect of the present invention, the conveying means comprises at least one support / retraction surface, which is movable along a second conveying path (another independent path) different from the first conveying path, from an infeed station to an outfeed station, and is configured to pull out the first portion of the glue-like material strip at the infeed station and transport it along the second conveying path to the outfeed station. The support / retraction surface allows the first step of the initiation to be performed without the risk of damage occurring as the strip moves through the drying chamber, which could result from contact between the first portion, i.e., the strip with the free end, and the conveying surface. [Brief explanation of the drawing]

[0032] The present invention will become apparent from the following further details with respect to several embodiments described only as non-limiting examples with reference to the accompanying drawings. [Figure 1] This is a schematic side view of a first embodiment of the apparatus according to the present invention, during an intermediate stage of its operation. [Figure 2] This diagram is similar to Figure 1, showing a later stage of the operation of the aforementioned device. [Figure 3] This is a schematic cross-sectional view of the line III-III in Figure 1. [Figure 4] This figure is similar to Figure 1, showing a second embodiment of the apparatus according to the present invention. [Figure 5] This figure is similar to Figure 1, showing a third embodiment of the apparatus according to the present invention. [Figure 6] This figure is similar to Figure 1, showing the first stage of operation of a third embodiment of the apparatus according to the present invention. [Figure 7] Figure 6 shows the apparatus in a later stage of the operation. [Modes for carrying out the invention]

[0033] As shown in the figure, the apparatus or dryer according to the present invention comprises a drying chamber 2 formed, i.e., partitioned by a wall 2A (only partially shown for clarity). The drying chamber has an inlet 4 into which strips 6 of a paste-like material for the manufacture of smoking articles to be dried are supplied.

[0034] Drying chamber 2 partitions the space in which the adhesive material strip 6 is dried, at least partially.

[0035] Strips of the adhesive material 6 are supplied to the inlet 4 and then enter the drying chamber 2.

[0036] It should be noted that the term "smoking products" is used to refer to various types of products, such as "non-combustion heating" type products (products that are only heated and do not burn), or products that burn at least partially, such as traditional cigarettes.

[0037] For example, the water content of the adhesive material strip 6 is 20% or more.

[0038] In particular, the moisture content can be set to 30% to 50%.

[0039] In particular, the moisture content can be set to 35% to 40%.

[0040] The glue-like material strip 6 is obtained, for example, by the method described in International Patent Publication No. 2020 / 058814. In this solution, the glue-like material strip 6 is obtained by a process known as lamination, in which a mixture with a moisture content of less than 50% is compressed between two rollers to form layers.

[0041] In other examples not illustrated, strips can also be obtained using a process known as casting, in which a liquid or semi-liquid material (generally with a water content of 50% or more) is poured onto a conveyor belt, for example, made of a metal material, which is then transported to a first drying chamber where a first drying process takes place, and then to a second drying chamber where drying is completed.

[0042] In the following description, the drying chamber 2 of the adhesive material strip 6, as generally referred to, may be, for example, the drying chamber for the strip 6 obtained by the method described in International Patent Publication No. 2020 / 058814, i.e., lamination, or it may be a second drying chamber for the strip obtained by the casting process.

[0043] The adhesive material of the strip 6 may include tobacco (e.g., reconstituted tobacco) or substances derived therefrom, tobacco or products derived therefrom, more generally, in the context of smoking products, one or more of cellulose, rapeseed, and hemp, in addition to aerosol-generating materials such as water and / or flavorings and / or binders and / or other additives. The drying chamber 2 also has an outlet 8 downstream of the inlet 4 along the conveying direction for discharging the dried strip 10.

[0044] Preferably, the dried strip 10 generally has a moisture content of about 7% to 15% and is prepared for immediate use for further processing (e.g., shredding), or prepared to be wound into a roll 12 for use in a later stage (as illustrated in the attached drawing).

[0045] The drying chamber 2 at least partially houses conveying means 20,14 for transporting strips 6 of the adhesive material.

[0046] These elements can be configured in different ways depending on the embodiment of the apparatus according to the present invention, as will become clear as this description progresses.

[0047] The drying chamber 2 is equipped with a heating system that includes, for example, one or more devices for generating and circulating a hot airflow, an infrared plate, or a microwave generator.

[0048] For example, in the embodiments illustrated in Figures 1 and 2, the heating system in the drying chamber 2 includes devices 28, 28', 30, and 30' for generating and circulating a flow of high-temperature dry air.

[0049] The drying chamber 2 and heating system form an oven in which strips 6 of the paste-like material are dried.

[0050] In the first embodiment illustrated in Figures 1 to 3, the transport means 20,14 for transporting the adhesive material strip 6 comprises a pickup unit 14 consisting of a first conveyor 14 equipped with, for example, a pair of endless chains 16 or other flexible drive elements such as cables, belts, etc. In the case of chains, they are arranged around a transmission sprocket 18, at least one of which is motorized and synchronized with the corresponding sprocket of the other chain. Preferably, the two sprockets 18 of the two chains 16 are rigidly connected to the same shaft to which an electric motor (not shown) that drives them is related.

[0051] The electric motor is controlled by a control unit that controls the operation of the entire device, but further explanation will be omitted.

[0052] The two upper transmission sprockets 18 of each chain 16 are positioned at the same level on the outside of the side wall 2A of the drying chamber 2 in the illustrated example.

[0053] The upper transmission sprocket 18 forms a horizontal stretch of the chain 16, which runs at substantially the same level as the roller conveyor 20. The roller conveyor also constitutes part of the device. The roller conveyor will be described in more detail below.

[0054] More specifically, the linear stretch of the first conveyor 14 travels from the infeed station, or entrance station 22, for the strips 6 of the glue-like material to be dried, to the outfeed station, where the dried strips 10 exit the device, forming a second transport path for the strips 6.

[0055] The linear stretch of the first conveyor 14 extends substantially throughout the interior of the drying chamber 2.

[0056] The remaining stretch of each chain 16 between the two upper sprockets 18 runs below a straight stretch, as can be easily seen from the diagram.

[0057] A bridge structure 24 is provided between the two chains 16 to support the strip 6 of the paste-like material to be dried. The bridge structure can be configured in various ways, but preferably it has multiple openings through which hot drying air flows. For example, the bridge structure 24 may consist of multiple thin sheets of metal, for example, with openings formed across its entire surface and fixed at both ends slightly spaced apart from the two chains 16. Alternatively, the bridge structure 24 may consist of a metal mesh portion with two longitudinal sides fixed to the chains 16, or it may consist of a metal mesh portion.

[0058] The bridge structure 24 constitutes means for receiving the strip 6, in particular, a support and retraction surface 24 for the strip 6.

[0059] The bridge structure 24 does not extend along the entire length of the two chains 16, but only along a portion of it. The bridge structure must be such that it can support the first portion of the glue-like material strip 6 and pull it in by friction, as will be described in detail below. In particular, the length of the bridge structure 24 can be approximately the same as the length of the straight upper stretch of the two chains 16.

[0060] Thus, the bridge structure 24 allows the initial first step of the process to be carried out without the risk of damage occurring as the material strip 6 moves through the drying chamber 2, which may result from contact between the initial portion, i.e., the strip 6 with the free end, and the conveying surface of the roller conveyor 20.

[0061] In the attached drawing, a winding station for winding the dry strip 10 onto a roll 12 is located downstream of the outfeed station. The winding station contributes to the forward movement of the conveyed strip and also has the function of pulling the strip in by winding it onto the roll.

[0062] As described above, the roller conveyor 20 can run at substantially the same level as the linear upward stretch of the chain 16 from the infeed station 22 and extend to the outlet 8 of the drying chamber 2 (as shown in the attached diagram), or it can reach the downstream end (outfeed station) of the linear upward stretch of the chain 16. In either case, the roller conveyor 20 forms the first transport path of the strip 6.

[0063] Preferably, the roller conveyor 20 extends inside the drying chamber 2 between the inlet 4 and the outlet 8.

[0064] The entrance 4 to drying chamber 2 can also be aligned with the infeed station 22.

[0065] The outlet 8 of drying chamber 2 can also be aligned with the outfeed station.

[0066] The axes of the individual rollers 26 of the roller conveyor 20 are perpendicular to the conveying direction of the strip 6 of the adhesive material.

[0067] At least some of the rollers 26, particularly those closest to the infeed station 22, are motorized, but preferably all of the rollers 26 are motorized. An advantage of having (at least some) motorized rollers 26 is that the strip 6 can be conveyed without rubbing against the rollers 26, thereby avoiding damage that may occur to the strip 6 as it moves along the drying chamber 2. In the first embodiment illustrated in Figures 1 to 3, the heating system includes at least one high-temperature dry air generator 28 in the upper portion of the two conveyors 14, 20 within the drying chamber 2. The high-temperature dry air generator flows a stream of hot, dry air over the conveyors 20, 14 via a suitable duct 30, blowing it onto the upper surface of the glue-like material strip 6 as it moves through the drying chamber 2 from inlet 4 to outlet 8.

[0068] In the first embodiment illustrated in Figures 1 to 3, the heating system comprises at least one high-temperature dry air generator 28 located in the lower portion of the two conveyors 14 and 20 within the drying chamber 2. The high-temperature dry air generator flows a stream of hot, dry air over the conveyors 20 and 14 via a suitable duct 30, blowing it onto the underside of the glue-like material strip 6 as it moves through the drying chamber 2 from inlet 4 to outlet 8. In other words, more generally, the heating system is outside the conveyors 20 and 14 and is separate from them. More specifically, the heating system does not coincide with the conveyors 20 and 14 (i.e., it is a separate entity, distinct from the two conveyors 20 and 14).

[0069] The high-temperature dry air generators 28, 28′ can be any known type, and the ducts associated therewith may, advantageously, consist of sheet metal boxes having conduits 32, 32′ with holes through which jets of high-temperature dry air pass and are sprayed onto the upper and lower surfaces of the glue-like material strips 6, extending across the entire width of the bridge conveyor 14 and the roller conveyor 20, with walls facing them.

[0070] The operation of the apparatus described here will be best understood by referring to the initial moment when the leading edge of the strip 6 of the glue-like material to be dried is located at the infeed station 22. In this state, the control unit of the apparatus commands the first conveyor 14 to move its bridge structure 24 so that the leading edge of it is close to the infeed station 22, and then to advance at substantially the same speed as the strip 6 of the glue-like material coming out of the infeed station 22.

[0071] As the first conveyor 14 moves forward, strips 6 of a glue-like material, for example, with a moisture content of approximately 35% to 50%, also move forward at the same speed and are placed on the bridge structure 24 of the first conveyor 14 itself.

[0072] The length of the bridge structure 24 is preferably defined as a function of the viscosity of the glue material strip 6, its weight, and the surface properties of the bridge structure 24, such that the first portion of the glue material strip 6 adheres securely to the surface of the bridge structure, thereby drawing the glue material strip 6 into the drying chamber 2 with the first conveyor 14 as it moves forward, with its first portion remaining completely stationary on the bridge structure 24.

[0073] Due to the viscosity of the glue-like material strip 6, it is virtually inevitable that the initial portion resting on the bridge structure 24 will be "marked" by the bridge structure; however, this is not a problem as the initial portion is a very small, minimal part of the product as a whole and can be discarded.

[0074] When the trailing edge of the bridge structure 24 passes the infeed station 22, the web portion of the adhesive material 6 following the first portion is placed directly on the roller conveyor 20, and in between, it is no longer covered by the bridge structure 24 of the first conveyor 14. Since the strip of adhesive material 6 is continuous, it continues to move forward, partly supported by the first conveyor 14 and partly by the roller conveyor 20.

[0075] As shown in Figure 2, once the bridge structure 24 of the first conveyor 14 completely disengages the cover of the roller conveyor 20 and is positioned underneath it, the first conveyor 14 stops and the drying equipment operates only with the roller conveyor 20.

[0076] The heating system in the drying chamber completes the drying process by reducing the moisture content of the glue-like material strip 6 to a desired value, for example, by an air jet, thereby obtaining a dried strip 10.

[0077] Preferably, when the bridge structure 24 of the first conveyor 14 completely disengages the cover of the roller conveyor 20, the latter (i.e., its rollers) is the sole means of guiding the strip toward the exit 8. Advantageously, in this respect, the present invention has the function of maintaining the material strip in contact with the rollers, while simultaneously distinguishing it from prior art solutions in which the material strip is guided along the roller supply path using a support belt, which significantly complicates the structural and functional aspects of the material drying process.

[0078] The surface of the roller 26 can be made perfectly smooth.

[0079] Alternatively, the surface of the roller 26 can be slightly knurled or embossed.

[0080] In the first case, both sides of the drying strip 10 are smooth, while in the second case, the underside of the drying strip 10 is also slightly knurled or embossed.

[0081] In both cases, the surface finish of the dried strip 10 is determined by the surface finish of the roller 26, and is free from unwanted marks left by the conveyor below, as in the prior art. In all cases, the roller 26 allows the strip 6 to be transported by rolling, but the surface finish of the roller 26 is selected to have a sufficiently high coefficient of friction so that the strip does not rub against the roller.

[0082] Preferably, the roller 26 is not heated. In the apparatus of the present invention, the heat required to dry the adhesive material strip 6 is supplied by the heating system. This aspect allows for a simpler apparatus structure. If the roller were heated, the overall complexity would increase, making uneven drying of the strip more likely and negatively impacting the quality of the final product. In fact, if the strip and the heated roller were in direct contact, parts of the strip would be exposed to higher temperatures than other parts, resulting in considerable thermal shock during the drying process.

[0083] It will be understood that the apparatus according to the illustrated preferred embodiment is a far improvement over conventional dryers. In particular, The required drying chamber 2 is much shorter than currently used drying chambers that provide the same performance, and the drying chamber 2 of the dryer according to the present invention is calculated to occupy approximately 30% less floor space and consume 40% less energy while having the same performance as a conventional dryer having a main dryer and a mesh dryer. Since the size of not only the drying chamber 2 but also the first conveyor belt 14 is reduced, energy consumption can be significantly reduced.

[0084] In particular, the fact that the strip 6 rolls on the second conveyor 20 means that the second conveyor 20 can perform rolling transport, that is, it does not form a flat surface. In this way, the strip 6 moves forward without rubbing against the second conveyor 20.

[0085] Furthermore, referring to the figure, it should be noted that, regardless of the size of the rollers 26, a connecting surface is preferably provided between one roller and the next roller, which functions as a bridge between the conveying surfaces of two consecutive rollers 26. This connecting surface preferably has a plurality of through holes, which allow hot, dry air to be blown through the through holes toward the underside of the strip to be dried.

[0086] The connecting surface can be made of, for example, steel, to facilitate the feeding and movement of the strip.

[0087] In the embodiment illustrated in Figure 4, where the principle of alternating operation between the first conveyor 14 and the roller conveyor 20 continues to apply, the heating system comprises a plurality of infrared plates 34 positioned between the individual rollers 26 of the roller conveyor 20. These infrared plates 34 can be provided in place of or in combination with connecting surfaces.

[0088] In the embodiment illustrated in Figure 5, a cooling chamber 36 is provided downstream of the drying chamber 2. Its function is to cool the dried strip 10, which may have reached a temperature too high to be suitable for subsequent processes after passing through the drying chamber 2, down to ambient temperature.

[0089] Although both the bridge conveyor 14 and the roller conveyor 20 traverse the cooling chamber 36, unlike prior art drying systems that have a cooling chamber, the apparatus according to the present invention enables considerable energy savings. This is because it does not use a single conveyor that passes from a high-temperature environment to a low-temperature environment, which is constantly changing from low to high temperatures. Although a single conveyor is used that moves through two environments of different temperatures, its size is reduced, and as a result its thermal inertia is reduced, so it does not require high energy consumption.

[0090] In the embodiments illustrated in Figures 6 and 7, the apparatus includes a first conveyor 14 within the drying chamber 2, which is substantially the same as the first conveyor 14 of the previously described embodiments, except that the configuration of the two chains 16 that move the bridge structure 24 is slightly different.

[0091] The roller conveyor 20 actually includes a row of lower rollers 26, 26' corresponding to the rollers of the previous embodiment.

[0092] The roller conveyor 20 is comprised of alternating fixed rollers 26 and rollers 26' mounted on a single liftable structure. The single liftable structure causes the rollers 26' to undergo substantially vertical translational movement.

[0093] The fixed roller 26 is motorized, but the roller 26' can be mounted in a driven state on a vertically movable structure, or it can also be motorized itself.

[0094] Furthermore, the roller conveyor 20 is equipped with a second row of rollers 38 mounted on each fixed shaft at a higher level than the fixed rollers 26 and facing the fixed rollers.

[0095] In this embodiment, for example, the heating system may include a single hot air generator 28 having a plurality of hollow protrusions 40 in its duct 30. The plurality of hollow protrusions have a trapezoidal cross-sectional shape that extends vertically to the roller 38 and extends laterally along the entire axial length of the roller itself. In modified examples not shown, there may be multiple hot air generators, or a hot air generator positioned above the roller and different drying means, such as an infrared plate, positioned below and / or to one side of the roller.

[0096] The inclined wall of the protrusion 40 has multiple holes, and a hot air jet is blown from these holes.

[0097] The operation of the apparatus in this embodiment is as follows: The process is the same as in the previous embodiment until the first portion of the strip 6 of the glue-like material to be dried is placed on the bridge structure 24 of the first bridge conveyor 14. After the entire bridge structure 24 passes through the roller conveyor 20 below and the next portion of the strip 6 of the glue-like material is placed on the rollers 26, 26', the structure rises in response to a command issued to the support structure of the roller 26' until the roller 26' substantially reaches the top of the lateral cavity partitioned by the protrusion 40 adjacent to the hot air duct 30.

[0098] As a result, the strips 6 of the adhesive material are arranged in a zigzag pattern (thus following the first zigzag path), their orientation is sequentially changed upward by the roller 38 and downward by the roller 26', and each strip faces the inclined wall of the protrusion 40, and is subjected to a jet of hot, dry air blown out from holes formed in the wall of the protrusion.

[0099] In this embodiment, the length of the drying chamber 2 can be significantly reduced without degrading the performance of the apparatus.

[0100] Generally speaking, the rollers 26 and 26' of roller conveyor 20 have a diameter of 50 to 100 mm.

[0101] The rollers 26, 26', which are arranged in a straight line, can have a center-to-center distance of between 200 and 300 millimeters. In this way, high-temperature dry air generators 28, 28' and / or infrared heating plates 34 can be placed between them.

[0102] In the embodiments shown in Figures 6 and 7, the height of the roller 26' (relative to the surface through which the fixed roller 26 passes) can be 250 to 750 millimeters, depending, for example, on the type of strip to be dried.

[0103] Compared to a conventional dryer having a main dryer and a mesh dryer that provides the same performance, the apparatus according to the fourth embodiment of the present invention is calculated to be able to reduce its longitudinal dimensions by approximately 70% to 80% and reduce energy consumption by approximately 40%.

[0104] Although the present invention has been described in relation to several preferred embodiments, it will be understood that it can be modified in several ways without departing from the scope of protection provided by industrial invention patents. [Prior art documents] [Patent Documents]

[0105] [Patent Document 1] International Patent Publication No. 2020 / 058814

Claims

1. A method for drying strips (6) of a paste-like material for the manufacture of smoking products, A step of supplying a strip (6) of adhesive material to a drying chamber (2), A method comprising the step of transporting the strip (6) of the adhesive material in the drying chamber (2) between the infeed station (22) and the outfeed station of the drying chamber (2), The conveying step is a method of rolling and transferring the strip (6) of the glue-like material on a plurality of conveying surfaces (20) that are continuously arranged along a first conveying path extending between the infeed station (22) and the outfeed station of the drying chamber (2).

2. The method according to claim 1, wherein the transport step is a method of drawing out the first portion of the strip (6) of the adhesive material in the infeed station (22) and transporting the first portion to the outfeed station along a second transport path different from the first transport path.

3. The method according to claim 2, wherein the first portion of the strip (6) of the adhesive material is placed on at least one support / retraction surface (24) and is transported by the support / retraction surface from the infeed station (22) to the outfeed station along the second transport path.

4. The method according to any one of claims 1 to 3, wherein the first transport path travels in a straight line between the infeed station (22) and the outfeed station of the drying chamber (2).

5. The method according to any one of claims 1 to 3, wherein the first transport path travels in a zigzag pattern between the infeed station (22) and the outfeed station of the drying chamber (2).

6. The method according to any one of claims 2 to 4, wherein the second transport path travels above the first transport path and across the first transport path.

7. The method according to claim 6, wherein the first and second transport paths are parallel to each other.

8. A method according to any one of claims 1 to 7, wherein the step of supplying the strip (6) to the drying chamber (2) and the step of transporting the strip (6) of the glue-like material within the drying chamber (2) are coordinated to provide the same longitudinal supply speed to the strip (2) being dried.

9. In the method according to any one of claims 1 to 8, A step of drawing the first portion of the glue-like material strip (6) from the infeed station (22) using a first conveyor (14) to draw it into the drying chamber (2), wherein the first conveyor (14) is configured such that, at one position, it forms a plurality of transport surfaces (20) that are continuously arranged along the first transport path and covers at least the first range of the roller conveyor (20) below the first transport path, and at other different positions it does not cover the roller conveyor (20), The process involves moving the strip (6) of the adhesive material forward on the first conveyor (14) in the drying chamber (2), and gradually releasing the cover of the roller conveyor (20) so that the portion of the strip (6) of the adhesive material following the first portion is placed directly on the roller conveyor (20), A method comprising the steps of stopping the first conveyor (14) when it completely releases the cover of the second roller conveyor (20), and allowing the roller conveyor to continue operating to receive and advance the strip (6) of the glue-like material in the drying chamber (2) so that the strip coming out of the drying chamber (2) becomes a dried strip (10).

10. The method according to claim 9, wherein the first conveyor (14) comprises a structure (24) on which the first portion of the strip (6) of the adhesive material is placed, the structure (24) comprising an opening for the passage of a flow of dry air.

11. A method according to claim 10, wherein the first portion of the strip (6) of the adhesive material is placed on a bridge structure (24).

12. A method according to one or more of the preceding claims, wherein a flow of high-temperature, dry air is blown onto the lower and upper surfaces of the strip (6) of the adhesive material as the strip (6) passes through the drying chamber (2).

13. A method according to one or more of the preceding claims, wherein the strip (6) of the paste-like material drawn out by the infeed station (22) and supplied to the drying chamber (2) has a water content of 20% to 50%, preferably 30% to 50%, and more preferably 35% to 40%.

14. A method according to one or more of the preceding claims, wherein the dried strip (10) coming out of the drying chamber (2) has a moisture content of 7% to 15%.

15. A method according to one or more of the prior claims, wherein the strip of the paste-like material is cooled after drying.

16. An apparatus for drying strips (6) of adhesive material for the manufacture of smoking products, Drying room (2), A supply means for supplying strips of adhesive material to the drying chamber (2), In an apparatus comprising conveying means (20, 14) for conveying the strip (6) of the adhesive material in the drying chamber (2) between the infeed station (22) and the outfeed station of the drying chamber (2), The conveying means (20, 14) is a device comprising a plurality of conveying surfaces (20) that are continuously arranged along a first conveying path extending between the infeed station (22) and the outfeed station, and that convey the glue-like material by rolling in contact with the strip (6).

17. The apparatus according to claim 16, wherein the first transport path is a device that travels in a straight line between the infeed station (22) and the outfeed station of the drying chamber (2).

18. The apparatus according to claim 16, wherein the first transport path is an apparatus that travels in a zigzag pattern between the infeed station (22) and the outfeed station of the drying chamber (2).

19. The apparatus according to any one of claims 16 to 18, wherein the conveying means (20, 14) comprises a roller conveyor (20) having a plurality of rollers that form the plurality of conveying surfaces (20) arranged continuously along the first conveying path, at least one of which is motorized.

20. An apparatus according to any one of claims 16 to 19, wherein the means for supplying the strip (6) of the adhesive material to the drying chamber (2) and the means for transporting the strip (6) within the chamber (2) are motorized and coordinated with each other to provide the same supply speed to the strip (6) of the adhesive material.

21. The apparatus according to any one of claims 16 to 20, wherein the transport means (20, 14) comprises at least one support / retraction surface (24) which is movable along a second transport path different from the first transport path from the infeed station (22) to the outfeed station, and is configured to pull out the first portion of the adhesive material strip (6) at the infeed station (22) and transport it along the second transport path to the outfeed station.

22. In the apparatus according to any one of claims 16 to 21, The conveying means (20, 14) includes a first conveyor (14) for conveying the glue-like material strip (6) along a second conveying path different from the first conveying path, the first conveyor being configured such that at a certain first position it covers at least the first range of the roller conveyor (20) located below the first conveying path, and at other different positions it does not cover the roller conveyor (20). The conveyor (14) is equipped with a receiving and transferring means (24) for receiving and transferring the first portion of the glue-like material strip (6) in the drying chamber (2), thereby gradually releasing the cover of the roller conveyor (20) so that the portion of the glue-like material strip (6) following the first portion is placed directly on the roller conveyor. The device is provided with moving means (16, 18) for moving the first conveyor (14) between the first position and the second position, wherein at the first position, the receiving and transferring means (24) receives the first portion of the glue-like material strip (6) from the supply means (22), and at the second position, the receiving and transferring means (24) completely releases the cover of the roller conveyor (20), and the roller conveyor receives the glue-like material strip (6) in the drying chamber (2) and continues to advance until it leaves the drying chamber (2).

23. The apparatus according to claim 22, wherein the first conveyor (14) comprises a pair of flexible traction elements (16) stretched between a plurality of transmission elements (18), at least one of which is motorized, and a bridge structure (24) connected to the pair of flexible traction elements (16) on which the first portion of the glue-like material strip (6) can be placed.

24. The apparatus according to claim 23, wherein the bridge structure (24) comprises a plurality of thin metal plates having openings for the passage of dry air and having both ends connected to the flexible traction element (16).

25. The apparatus according to claim 23, wherein the bridge structure (24) comprises a metal mesh portion.

26. The apparatus according to one or more of claims 16 to 25, wherein the drying chamber (2) is equipped with at least one hot air generator (28, 28'), the hot air generator is associated with a conveyor (30, 30'), and the hot air generator is configured to blow a jet of hot air onto at least one surface of the strip (6) of the glue-like material as it moves through the drying chamber (2).

27. An apparatus according to one or more of claims 16 to 26, comprising a plurality of infrared heating plates (34) positioned between a plurality of rollers (26) of the roller conveyor (20) and facing the lower surface of the strip (6) of the adhesive material advancing in the drying chamber (2).

28. The apparatus according to claims 18 and 19, wherein the roller conveyor (20) comprises a series of first electric rollers (26), a series of second rollers (38) that cover the first rollers (26) and together form a passage through which the strip (6) of the adhesive material passes, and a series of third rollers (26'), wherein the series of third rollers are arranged alternately with the first rollers (26) and are mounted in a structure that allows them to move vertically between a lower position where they are positioned at substantially the same level as the first rollers (26) and an upper position where they are positioned at a higher level than the second rollers (38).

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