A unit for laminating a continuous plant-based layer, in particular of the smoking articles industry

Abstract

A unit (1) for laminating a continuous plant-based layer (S), in particular of the smoking articles industry, comprising at least two laminating stages (10, 20, 30, 40), each comprising a pair of opposed laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b), mutually defining a passage gap and 5 configured to perform a lamination of a material thus obtaining a continuous layer (S). The unit (1) further comprises a thermostating system (100) operating by means of a heat transfer fluid and configured to regulate the temperature of the laminating stages (10, 20, 30, 40). The thermostating system (100) comprises at least one thermostating circuit 10 (200, 300) connected to each laminating stage (10, 20, 30, 40) and a single thermostating control unit (C), connected to the at least one thermostating circuit (200, 300) and configured to control the thermostating system (100).

Description

[0001] DESCRIPTION

[0002] A UNIT FOR LAMINATING A CONTINUOUS PLANT-BASED LAYER, IN PARTICULAR OF THE SMOKING ARTICLES INDUSTRY

[0003] Technical field

[0004] The present invention relates to a unit for laminating a continuous plantbased layer, in particular of the smoking articles industry.

[0005] Background art

[0006] In the relevant field of the present invention, laminating a continuous plantbased layer is known, where the expression "plant-based" is intended to mean a material (tobacco or non-tobacco) obtained by grinding or other similar procedure in order to modify the grain size thereof in order to promote subsequent mixing treatments. In particular, the continuous layer is intended to be a semi-finished product obtained from the mixing and processing of at least one dry plant-based component made of fibers and / or powder, such as, for example, tobacco or non-tobacco (cellulose or cellulose derivatives, rapeseed, hemp, straw or other varieties, hemp, aromatic leaves or other) with a moist component, such as, for example, water and one or more additives according to the generality of the invention. In particular, lamination is an essential process for producing continuous layers. This process is carried out through a unit comprising at least one laminating stage, each provided with a pair of opposing laminating rollers, mutually defining a passage gap, through which the material is passed so as to be processed in the form of a continuous layer having calibrated (laminated) thickness. The laminating stages may be vertical laminating stages or horizontal laminating stages.

[0007] In the field relating to the present invention, the need is strongly felt to ensure uniformity in the thickness of the continuous plant-based layer. However, a problem known in the laminating process concerns the change in temperature caused by friction between the surfaces of the rollers and the laminated material. This friction generates heat, which may result in temperature changes during the laminating process. Since the laminating rollers are conventionally made of metal material, they are subject to thermal expansion. Therefore, the temperature change may cause a size change of the rollers, affecting the thickness of the laminated material, making it irregular.

[0008] Furthermore, it has been observed that a different temperature of the rollers with respect to an optimal value causes an alteration of the physical properties of the material and, consequently, inadequate lamination.

[0009] In this context, the technical task of the present invention is thus to provide a unit for laminating a continuous plant-based layer, in particular of the smoking articles industry, which overcomes the drawbacks of the prior art.

[0010] Object of the invention

[0011] It is therefore the object of the present invention to provide a unit for laminating a continuous plant-based layer, in particular of the smoking articles industry capable of obtaining a qualitatively satisfactory finished product, with particular reference to the thickness, which is efficient and structurally optimized.

[0012] The specified technical task and the specified object are substantially achieved by a unit for laminating a continuous plant-based layer, in particular of the smoking articles industry, according to the present invention.

[0013] In particular, the unit comprises at least two laminating stages, each provided with a pair of opposite laminating rollers, mutually defining a passage gap and configured to laminate a material, obtaining a continuous layer. The at least two laminating stages are arranged in succession along a processing path of the continuous layer.

[0014] In one embodiment, the laminating stages comprise respective different, separate pairs of rollers, e.g. mounted on respective support frames, which are mutually spaced apart. In this configuration, the web exiting the first stage is detached from the rollers of the first stage and transferred, suspended or resting on a support member (e.g. a conveyor belt) to the pair of rollers of the subsequent stage.

[0015] In a different embodiment, two or more laminating stages are integrated with each other into a single train of rollers (e.g. formed by three tangent rollers) where successive tangency zones define successive laminations. In this configuration, the web is not detached from the rollers but remains stuck to at least one of the rollers, common to two adjacent laminating stages.

[0016] The unit comprises a thermostating system operating by means of a heat transfer fluid and configured to regulate the temperature of the laminating stages: the system comprises at least one thermostating circuit connected to each laminating stage and a single thermostating control unit, connected to the at least one thermostating circuit and configured to control the thermostating system.

[0017] The Applicant has observed that the aforesaid laminating system, which implements a single thermostating control unit, ensures a reduction in costs and structural simplification, as well as simultaneously ensuring an efficient and reliable process in order to obtain a qualitatively satisfactory product.

[0018] First, the thermostating allows controlling the temperature of the rollers, with consequent optimization of the laminating process.

[0019] Furthermore, management by means of a single thermostating control unit is structurally and financially advantageous. This simplifies the system control and maintenance operations. Furthermore, by using a single control unit, the purchase and installation costs are optimized. Furthermore, maintenance and calibration are concentrated on a single unit, thus contributing to a great saving in terms of time and resources. In summary, therefore, the adoption of a single thermostating control unit for the entire laminating system not only simplifies control and reduces costs, but it also ensures optimal overall efficiency and reliability. The unit according to the present invention may further comprise one or more of the technical aspects that will be outlined below.

[0020] According to an aspect, the expression “at least two laminating stages” is intended to mean that the unit comprises a plurality of laminating stages in succession, where each stage operates on the material laminated by the preceding stage. The laminating unit preferably comprises three or more stages. According to a preferred exemplary and therefore non-limiting embodiment, the unit comprises four laminating stages arranged in succession along the aforesaid processing path of the continuous layer. Advantageously, said technical feature allows a progressive reduction in the thickness of the continuous layer, thus improving the quality and consistency of the final continuous layer. Each pair of rollers may be regulated to apply a specific and optimal pressure for the process phase, minimizing mechanical stress on the material and reducing the risk of flaws or imperfections.

[0021] According to an aspect, independently of the number of laminating stages, the laminating stages may be vertical laminating stages and / or horizontal laminating stages. In other words, the laminating stages of the unit may be exclusively of the vertical type, exclusively of the horizontal type, or combined, as a function of specific design requirements. For example, the laminating unit could be configured so that the first laminating stages are vertical laminating stages while the subsequent laminating stages are horizontal laminating stages. According to a preferred exemplary and therefore non-limiting embodiment, the laminating stages are exclusively of the horizontal type. In particular, each laminating stage comprises a lower laminating roller and an upper laminating roller, which are mutually opposite to each other to define the aforesaid passage gap of the continuous layer.

[0022] According to an aspect, independently of the number and type of lamination, the thermostating system may comprise a thermostating circuit of the rollers configured to regulate a surface temperature of the laminating rollers.

[0023] In other words, the thermostating circuit is associated with each laminating roller of the unit and serves to keep the surface temperature of the laminating rollers at a desired and constant level. This may involve heating or cooling the laminating rollers depending on the requirements of the laminating process, ensuring that the temperature remains optimal in order to obtain the best properties of the laminated material, such as uniformity, consistency and quality, as well as keeping the size of the laminating rollers constant.

[0024] The thermostating circuit of the rollers may comprise a heater or a cooler, for example, configured to regulate the temperature of the heat transfer fluid.

[0025] The thermostating circuit of the rollers is preferably configured to feed the heat transfer fluid to the laminating rollers at a temperature between 10°C and 50°C. Even more preferably, the thermostating circuit of the rollers is configured to feed the heat transfer fluid to the laminating rollers at a temperature between 15°C and 35°C.

[0026] The thermostating circuit of the rollers is preferably configured to keep the work surface of the laminating rollers at a temperature between 10°C and 50°C. Even more preferably, the thermostating circuit of the rollers is configured to keep the work surface of the laminating rollers at a temperature between 15°C and 35°C.

[0027] In other words, the heat-transfer fluid of the thermostating circuit of the rollers preferably has the same operating temperature as the work surface of the laminating rollers.

[0028] To this end, each laminating roller may comprise an internal cavity, preferably extending over the entire length of the roller, adapted to receive the heat transfer fluid: according to said embodiment, the thermostating circuit of the rollers is connected to the internal cavities of the laminating rollers. Each inner cavity defines a respective path for the heat transfer fluid inside the laminating roller. In particular, the internal cavity has at least one feed mouth and at least one discharging mouth for the heat transfer fluid.

[0029] The at least one feed mouth and the at least one discharging mouth are preferably made close to at least one end of the respective laminating roller. Even more preferably, the at least one feed mouth and the at least one discharging mouth are made close to the same end of the respective laminating roller.

[0030] Functionally, the thermostating circuit of the rollers feeds the heat-transfer fluid inside the internal cavity of the laminating rollers through the at least one feed mouth, the heat transfer fluid is circulated inside the cavity and then discharged from the at least one discharging mouth to return to the thermostating circuit of the rollers.

[0031] According to an aspect, the thermostating circuit of the rollers may be a closed circuit. In other words, the heat transfer fluid circulates continuously without being exposed to the external environment. In particular, the heat transfer fluid is heated or cooled to a specific temperature and then circulated through the laminating rollers. After releasing or absorbing heat from the laminating rollers, the fluid returns to the thermostating control unit to be regulated again to the desired temperature and recirculated. However a feed branch and / or a discharging branch may be provided to feed / discharge the transfer fluid inside the thermostating circuit of the rollers. However, during normal operation of the thermostating circuit of the rollers 200, it preferably operates as a closed circuit.

[0032] According to an aspect, the at least one thermostating circuit of the rollers may be configured so as to connect, in parallel, at least two laminating stages. In other words, the parallel connection of the laminating rollers with respect to the thermostating control unit means that the heat transfer fluid is distributed simultaneously to multiple laminating stages directly from the thermostating control unit.

[0033] According to an aspect, the thermostating circuit of the rollers may be configured so as to connect, in series, at least two laminating stages. In other words, this means that the heat transfer fluid, regulated by the thermostating control unit, sequentially flows through the laminating stages.

[0034] When the stages are preferably connected in series, the thermostating circuit of the rollers is configured so that the circulation of said heat transfer fluid between said laminating stages is opposite the processing path of the continuous layer. In other words, the countercurrent flow of the heat transfer fluid with respect to the feed direction of the laminated material. Advantageously, with the countercurrent flow, the temperature of the heat transfer fluid and the laminating stages tends to stabilize along the path, reducing thermal fluctuations. This also helps to keep a more uniform temperature across the entire continuous layer, improving the quality of the final product.

[0035] According to a particularly advantageous embodiment, the thermostating circuit of the rollers is configured so as to connect, in parallel, the last laminating stage and the penultimate laminating stage to said thermostating control unit, and in which said thermostating circuit of the rollers is configured so as to connect to one another, in series, the remaining laminating stages arranged upstream of said penultimate laminating stage.

[0036] By connecting, in parallel, the last laminating stage and the penultimate laminating stage to the thermostating control unit, a more precise control of the temperature in the final laminating stages is achieved, directly influencing the quality of the continuous layer. This allows an independent and optimized regulation of the laminating conditions to improve the consistency of the final product. Furthermore, by connecting the remaining stages, in series, arranged upstream of the penultimate stage, the sequential flow of the heat transfer fluid helps to stabilize the thermal gradient along the processing path, improving the overall thermal efficiency and reducing the risk of thermal and mechanical stress on the laminated material. This configuration increases the operational flexibility and capacity to adapt to different materials and production conditions, promoting greater quality and uniformity of the continuous layer in the industrial process. Furthermore, advantageously, the benefits of this configuration are amplified considering that the final stages are decisive for the quality of the final product, making optimal regulation of the temperature essential in these steps.

[0037] According to an aspect, independently of how the laminating stages are connected to one another, the thermostating circuit of the rollers may be configured so as to connect, in series, the laminating rollers of a same pair of laminating rollers. Advantageously, said technical feature reduces the complexity of the laminating unit, minimizing the number of connections and components required to manage and control the heat transfer fluid flow.

[0038] According to the embodiment in which the laminating stages are of the horizontal laminating type, the thermostating circuit of the rollers is configured so that the upper roller is connected, in series, downstream of the lower roller.

[0039] According to an aspect, independently of the presence or configuration of the thermostating circuit of the rollers, at least one roller of each laminating stage may be a motorized roller associated with a respective engine. Each engine preferably comprises a motor, configured to provide the power needed for the rotation of the respective laminating roller, and a reducer, interposed between the motor and the respective roller and configured to reduce the rotation speed with respect to the motor and increase the available torque. All the laminating rollers of the unit are preferably motorized rollers equipped with a respective engine.

[0040] According to said embodiments, the thermostating system may comprise a thermostating circuit of the engine of the laminating rollers: the thermostating circuit of the engine is configured to regulate a temperature of the motors and / or the reducers of the respective engines.

[0041] The thermostating circuit of the engine may be configured to regulate the temperature of the motors and / or reducers of the laminating rollers of all the laminating stages, or only some.

[0042] According to a preferred exemplary and therefore non-limiting embodiment, the thermostating circuit of the engine is configured to regulate the temperature of the motors and / or reducers of the laminating rollers of the last two laminating stages.

[0043] According to an aspect, the thermostating circuit of the engine of the laminating rollers may be an open circuit. In particular, the circuit may be connected to an external source of heat transfer fluid configured to feed supply heat transfer fluid into the thermostating circuit of the engine of the laminating rollers, and to an external heat transfer fluid discharge configured to discharge used heat transfer fluid from the thermostating circuit of the engine of the laminating rollers.

[0044] The thermostating circuit of the engine of the rollers is preferably configured to feed the heat-transfer fluid to the engines at a temperature between 5°C and 30°C, preferably between 5°C and 20°C.

[0045] According to an aspect, the thermostating circuit of the engine of the laminating rollers may be configured so as to connect the laminating stages in parallel. In other words, the connection in parallel with respect to the thermostating control unit means that the heat-transfer fluid is distributed simultaneously to multiple laminating stages, directly from the thermostating control unit.

[0046] According to an aspect, in the embodiment in which the laminating rollers of each laminating stage are both motorized, the thermostating circuit of the engine of the rollers may be configured so as to connect in parallel the engines of the same pair of laminating rollers.

[0047] According to a preferred embodiment, when the thermostating circuit of the rollers is a closed circuit and the thermostating circuit of the engine of the rollers is an open circuit, the thermostating control unit may comprise a heat-transfer device configured to transfer heat between the thermostating circuit of the rollers and the thermostating circuit of the roller engine. Advantageously, said technical feature ensures a significant advantage in energy recovery. During operation, the heat dissipated by the engines of the rollers may be recovered and transferred to the laminating rollers, improving the overall efficiency of the plant. This reduces the overall energy consumption of the unit and optimizes the operation thereof, since the rollers are operated at a controlled temperature without undergoing the drawback of cooling caused by contact with the material being laminated. As will become more apparent in the following present description, the heat-transfer device may be a simple heat exchanger, such as for example a plate heat exchanger, or a system of the heat pump or refrigeration-cycle type.

[0048] According to a particularly advantageous embodiment, the thermostating circuit of the engine of the rollers comprises a first branch, configured to convey the heat-transfer fluid through the engines, and a second branch, parallel to the first branch, configured to convey the heat-transfer fluid through the aforesaid heat-transfer device: in this embodiment, the first and the second branch have at least one common dividing point arranged upstream of the engines and the transfer device, respectively, and at least one common connecting point arranged downstream of the engines and the transfer device, respectively. In other words, the thermostating control unit and the engines are arranged in parallel. In particular, the transfer fluid coming from the external source of heat transfer fluid is split between the first branch and the second branch so as to reach the engines and the exchanger of the thermostating control unit, respectively. Said splitting takes place close to the at least one common dividing point. Subsequently, the first branch and the second branch, returning from the engines and from the transfer device, respectively, are joined at the common connecting point so that the heat transfer fluid coming from the engine and the heat transfer fluid coming from the transfer device join up again to be sent to the external discharge.

[0049] According to an embodiment, the thermostating circuit of the rollers is configured to heat the laminating rollers so as to keep the surface temperature thereof constant, while the thermostating circuit of the engine of the rollers is configured to cool the aforesaid engines of the rollers so as to keep the temperature thereof constant. Therefore, in said embodiment, the heat transfer fluid coming from the external source is conveyed partly to the first branch to cool the engines and partly to the second branch to enter the thermostating control unit. Inside the thermostating unit, the heat transfer fluid of the thermostating circuit of the engine of the rollers is cooled by means of the aforesaid heat transfer device, which simultaneously heats the heat transfer fluid present in the thermostating circuit of the rollers. Therefore, the heat transfer fluid cooled by the thermostating control unit present in the second branch joins the heat transfer fluid again present in the first branch, which has been heated by the engines of the rollers. The heat transfer fluid is therefore discharged to the external discharge at a temperature substantially equal to the inlet temperature. In this exemplary embodiment, the heat transfer device is a heat pump or a refrigeration cycle.

[0050] According to an aspect, independently of the presence and / or configuration of the thermostating circuit of the rollers and the thermostating circuit of the engine of the rollers, the thermostating system comprises a plurality of pumping devices of the heat transfer fluid and flow control devices of the heat transfer fluid, such as, for example control valves, and a control unit, connected to the control devices and configured to regulate the control devices. Thus, advantageously, it is possible to control the recirculation of the heat transfer fluid inside the system.

[0051] According to an aspect, the thermostating system may comprise a plurality of temperature measuring sensors for the laminating rollers and / or engine of the laminating rollers, connected to the control unit and configured to detect respective temperature values of the laminating rollers or the engine of the laminating rollers: in said embodiment, the control unit is configured to command the pumping devices and the heat transfer fluid flow control devices as a function of the measurements. Alternatively or simultaneously, the thermostating system may comprise a plurality of temperature measuring sensors of the heat transfer fluid, connected to the control unit and configured to detect respective temperature values of the heat transfer fluid inside the branches of the thermostating circuit: in this embodiment, the control unit is configured to command the pumping devices and heat transfer fluid flow control devices as a function of the measurements.

[0052] Advantageously, the integration of temperature sensors offers several significant advantages in the thermostating process. These sensors allow continuous, accurate monitoring of critical temperatures inside the laminating unit: the control unit uses this information to dynamically regulate the pumping devices and the flow control devices of the heat transfer fluid. This not only optimizes thermal efficiency and heat transfer along the laminating rollers, but also protects the components from excessive heating or cooling. Furthermore, the sensor based control contributes to keeping stable, uniform operating conditions, improving the quality and consistency of the finished product and reducing the overall energy consumption of the system.

[0053] According to an aspect, the thermostating system comprises tubes for conveying the heat transfer fluid from the thermostating control unit to the laminating stages and vice versa, which are preferably overhead with respect to the laminating stages. Advantageously, this technical feature facilitates control of the flow of the heat transfer fluid, allowing a more efficient and direct movement between the thermostating control unit and the laminating stages. Furthermore, the overhead tubes may contribute to safer and more accessible management of operations of maintenance and inspection, facilitating access for preventive or corrective maintenance interventions.

[0054] Further features and advantages of the present invention will become more apparent from the exemplary, and therefore non-limiting description of an embodiment of a unit for laminating a continuous plant-based layer, in particular of the smoking articles industry, according to the invention.

[0055] Brief description of the drawings

[0056] Said description will be set out below with reference to the accompanying drawings, purely provided for indicative and thus non-limiting purposes, showing:

[0057] - figure 1 shows a diagrammatic view of a unit for laminating a continuous plant-based layer, in particular of the smoking articles industry, according to the present invention;

[0058] - figure 2 shows a diagrammatic view of a first part of the thermostating system of the unit in figure 1 ;

[0059] - figure 3 shows a diagrammatic view of a second part of the thermostating system of the unit in figure 1 .

[0060] Detailed description of preferred embodiments of the invention

[0061] With reference to the appended figures, reference numeral 1 denotes a preferred embodiment of a unit for laminating a continuous plant-based layer “S”, in particular of the smoking articles industry.

[0062] The continuous layer "S" according to the present invention is a layer based on material of plant origin. In the present description, the expression "plant origin" is intended to mean a plant-based material (tobacco or non-tobacco) processed by grinding or another similar procedure to modify the grain size thereof in order to promote subsequent mixture treatments. In particular, it is intended to mean that the continuous layer is a semi-finished product obtained from the mixing and processing of at least one dry plant component, such as, for example tobacco or nontobacco (rapeseed, hemp, straw or other varieties, cellulose or cellulose derivatives, hemp, aromatic leaves or others) with a moist component, such as water, for example and one or more additives, according to the generality of the invention. In particular, the material is in the form of a paste having a pasty consistency (“dough”), with a water content of less than 65% by weight, preferably less than 60%, even more preferably comprised between 15% and 50% by weight, in particular comprised between 20% and 35% by weight.

[0063] As visible from figure 1 , the unit 1 comprises four laminating stages 10, 20, 30, 40, each provided with a respective pair of opposite laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b mutually defining a passage gap and configured to perform a lamination of a material, obtaining the continuous layer “S”. In particular, the four laminating stages 10, 20, 30, 40 are arranged in succession along a processing path “L” of the continuous layer “S”.

[0064] The laminating stages 10, 20, 30, 40 are all of the horizontal laminating type: each pair of rollers comprises a respective lower roller 10a, 20a, 30a, 40a and a respective upper roller 10b, 20b, 30b, 40b.

[0065] Each laminating roller 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b of the unit 1 is a motorized roller associated with a respective engine “M”. Each engine “M” comprises a motor, configured to supply the power needed for the rotation of the respective laminating roller, and a reducer, configured to reduce the speed of rotation with respect to the motor and increase the torque available for the efficient lamination of the tobacco.

[0066] According to a different embodiment, not shown but encompassed in the invention, two or more laminating stages, preferably all the laminating stages, are integrated with one another in a single train of rollers (e.g. formed by three tangent rollers) where successive tangency zones define successive laminations. In this configuration, the web is not detached from the rollers but remains stuck to at least one of the rollers, common to two adjacent laminating stages.

[0067] The unit 1 further comprises a thermostating system 100, operating by means of a heat transfer fluid and configured to regulate the temperature of the laminating stages 10, 20, 30, 40: the thermostating system 100 comprises at least one thermostating circuit 200, 300, connected to each laminating stage 10, 20, 30, 40, and a single thermostating control unit “C”, connected to the at least one thermostating circuit 200, 300 and configured to control the thermostating system 100.

[0068] As can be seen from figures 2 and 3, and as will be more apparent in the present description below, the thermostating system 100 comprises two thermostating circuits 200, 300: a thermostating circuit of the rollers 200 and a thermostating circuit of the engine of the rollers 300.

[0069] The attached figure 2 shows the preferred embodiment of the thermostating circuit of the rollers 200.

[0070] The thermostating circuit of the rollers 200 is a closed circuit. The thermostating circuit of the rollers 200 is configured to regulate the surface temperature of the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b.

[0071] A feed branch and / or a discharging branch (not shown) may be provided to feed / discharge the transfer fluid into the thermostating circuit of the rollers 200. However, during normal operation of the thermostating circuit of the rollers 200, it preferably operates as a closed circuit.

[0072] Structurally, each laminating roller 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b has a respective internal cavity (not shown), preferably extending over the entire length of the laminating roller 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b, adapted to receive the heat transfer fluid: the thermostating circuit of the rollers 200 is connected to the internal cavities of the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b. In particular, the thermostating circuit of the rollers 200 is configured to heat or cool the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b by means of the heat transfer fluid so as to regulate the surface temperature of the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b.

[0073] The thermostating circuit of the rollers 200 is preferably configured to feed the heat transfer fluid to the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b at a temperature between 10°C and 50°C. Even more preferably, the thermostating circuit of the rollers 200 is configured to feed the heat transfer fluid to the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b at a temperature between 15°C and 35°C.

[0074] In other words, the heat transfer fluid of the thermostating circuit of the rollers 200 preferably has the same operating temperature as the work surface of the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b.

[0075] In the illustrated embodiment, the thermostating circuit of the rollers 200 is configured to connect, in parallel, the third laminating stage 30 and the fourth laminating stage 40. Furthermore, the thermostating circuit of the rollers 200 is configured so as to connect, in series, the remaining two laminating stages 10, 20 to the third laminating stage 30: the circulation of the heat transfer fluid between the laminating stages 10, 20, 30 is opposite the processing path “L” of the continuous layer. In other words, the second laminating stage 20 is connected, in series, downstream of the third laminating stage 30 and the first laminating stage 10 is connected, in series, downstream of the second laminating stage 20.

[0076] In the illustrated embodiment, the thermostating circuit of the rollers 200 is configured so as to connect, in series, the laminating rollers of one same pair of laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b. The thermostating circuit of the rollers 200 is preferably configured so that the upper roller 10b, 20b, 30b, 40b is connected, in series, downstream of the lower roller 10a, 20a, 30a, 40a.

[0077] The thermostating circuit of the rollers 200 may further comprise a heater or a cooler (not shown).

[0078] The attached figure 3 shows the preferred embodiment of the thermostating circuit of the engine of the rollers 300.

[0079] The thermostating circuit of the engine of the rollers 300 is configured to regulate a temperature of the motors and / or reducers of the engines “M”. The thermostating circuit of the engine of the rollers 300 is preferably configured to extract heat from the motors and / or reducers of the engine “M” of the rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b so as to cool them and keep the temperature constant. The thermostating circuit of the engine of the rollers 300 is configured to feed the heat transfer fluid to the engines “M” at a temperature between 5°C and 30°C, preferably between 5°C and 20°C.

[0080] The thermostating circuit of the engine of the rollers 300 is an open circuit. In particular, the thermostating circuit of the engine of the rollers 300 is connected to an external source “A” of heat transfer fluid configured to feed supply heat transfer fluid into the thermostating circuit of the engine of the rollers 300, and to an external heat-transfer fluid discharge “B” configured to discharge used heat transfer fluid from the thermostating circuit of the engine of the rollers 300.

[0081] In the illustrated embodiment, the thermostating circuit of the engine of the rollers 300 is configured so as to connect the rolling stages 10, 20, 30, 40 in parallel.

[0082] Furthermore, in the illustrated embodiment, the thermostating circuit of the engine of the rollers 300 is configured so as to connect, in parallel, the engines “M” of the same pair of laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b.

[0083] As shown in figure 1 , the thermostating control unit “C” comprises a heat transfer device configured to transfer heat between the thermostating circuit of the rollers 200 and the thermostating circuit of the engine of the rollers 300. In the described embodiment, the heat transfer device may preferably be a heat pump or a refrigeration cycle configured to transfer heat from the thermostating circuit of the engine of the rollers 300 to the thermostating circuit of the rollers 200.

[0084] In this embodiment, the thermostating circuit of the rollers 300 comprises at least one first branch 301 , configured to convey the heat transfer fluid through the engines “M”, and a second branch 302, parallel to the at least one first branch 301 , configured to convey the heat transfer fluid through the heat transfer device, and thus into the thermostating control unit “C”. The at least one first branch 301 and the second branch 302 have at least one common dividing point 303 arranged upstream of the engines “M” and of the heat transfer device, respectively and at least one common connecting point 304 located downstream of the engines “M” and of the heat-transfer device, respectively.

[0085] According to an aspect, the thermostating system 100 comprises a plurality of heat transfer fluid pumping devices (not shown) and heat transfer fluid flow control devices (not shown), such as, for example, control valves, and a “U”-shaped control unit, connected to the control devices and configured to regulate said control devices.

[0086] The heat transfer fluid flow control devices are preferably arranged upstream of the laminating stages 10, 20, 30, 40 and / or of the respective engines “M”, so as to be selectively activatable / deactivatable, so as to convey, or not convey, the heat transfer fluid inside those laminating stages 10, 20, 30, 40.

[0087] The thermostating system 100 further comprises a plurality of temperature measuring sensors (not shown) of the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b and / or of the engine “M” of the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b, connected to the aforesaid “LT- shaped control unit and configured to detect respective temperature values of the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b or of the engine “M” of the laminating rollers 10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b: the “U”-shaped control unit is configured to command the pumping devices and the heat transfer fluid flow control devices as a function of the aforesaid measurements.

[0088] Alternatively or simultaneously, the thermostating system 100 may include a plurality of temperature measuring sensors (not shown) of the heat transfer fluid, connected to the control unit and configured to detect respective temperature values of the heat transfer fluid inside the branches of the thermostating circuit: in this embodiment, the control unit is configured to command heat transfer fluid flow pumping and control devices, as a function of the measurements. As shown in figure 1 , the thermostating system 100 comprises tubes for conveying the heat transfer fluid from the thermostating control unit “C” to the laminating stages 10, 20, 30, 40 and vice versa, which are arranged and / or configured to be overhead with respect to the same laminating stages 10, 20, 30, 40.

[0089] The present invention achieves the set objects by eliminating the drawbacks highlighted in the prior art.

[0090] It should be noted that unit 1 , as described and / or claimed, is capable of ensuring a reduction in costs and a structural simplification of the unit and, at the same time, it is capable of ensuring a qualitatively satisfactory finished product.

[0091] First and foremost, said result is achieved by virtue of the use of a thermostating system 100 provided with a single thermostating control unit “C”. First of all, the structural simplicity represents a considerable advantage, since a single thermostating control unit “C” allows reducing the complexity of the entire system, simplifying installation, maintenance and operational management. This also leads to a reduction in costs, both in terms of the initial investment and operating expenses, since it eliminates the need for a plurality of thermostating control units and relative wiring. Furthermore, a single thermostating control unit “C” allows optimal management of the heat transfer fluid and temperature regulation, allowing a precise and uniform control of the thermal parameters through the various laminating stages 10, 20, 30, 40. This means greater energy efficiency and improved quality of the final product, since the temperatures may be kept constant and uniform along the entire processing path “L”. Finally, centralization of control facilitates monitoring and diagnosis operations, making it easier to identify and resolve any anomalies or malfunctioning of the unit 1 .

[0092] Furthermore, heat exchange operation between the thermostating circuit of the engine of the rollers and the thermostating circuit of the laminating rollers allows obtaining a thermally inert system, which (in case of an open circuit for the thermostating of the engine of the rollers) may discharge the heat transfer fluid at a temperature substantially identical to the temperature of the heat transfer fluid at the inlet. In fact, the excess heat is transferred to the thermostating circuit of the rollers to keep the optimal temperature of the surface of the rollers.

Claims

CLAIMS1. A unit (1 ) for laminating a continuous (S) plant-based layer, in particular of the smoking articles industry, comprising:- at least two laminating stages (10, 20, 30, 40), each comprising a pair of opposite laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b), mutually defining a passage space and configured to laminate a material obtaining a continuous layer (S); said at least two laminating stages (10, 20, 30, 40) being arranged in succession along a processing path (L) of the continuous layer (S);- a thermostating system (100) operating by means of a heat transfer fluid and configured to regulate the temperature of said laminating stages (10, 20, 30 40), said thermostating system (100) comprising at least one thermostating circuit (200, 300) connected to each laminating stage (10, 20, 30, 40) and a single thermostating control unit (C), connected to the at least one thermostating circuit (200, 300) and configured to control said thermostating system (100).

2. A unit (1 ) according to claim 1 , comprising three or more laminating stages (10, 20, 30, 40).

3. A unit (1 ) according to claim 1 or 2, wherein each laminating roller (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b) has an internal cavity, preferably extending for the entire length of the laminating roller (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b), adapted to receive said heat transfer fluid and wherein said at least one thermostating circuit is a thermostating circuit of the rollers (200) connected to the internal cavities of the laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b) and configured to regulate a surface temperature of said laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b).

4. A unit (1 ) according to claim 3, wherein said thermostating circuit of the rollers (200) is configured to feed the heat transfer fluid to the laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b) at a temperature from 10°C to 50°C, preferably at a temperature from 15°C to 35°C.

5. A unit (1 ) according to any one of the preceding claims, wherein said thermostating circuit of the rollers (200) is configured so as to connect, in parallel, at least two laminating stages (10, 20, 30, 40).

6. A unit (1 ) according to any one of the preceding claims, wherein said thermostating circuit of the rollers (200) is configured so that it connects, in series, at least two laminating stages (10, 20, 30 40), preferably said thermostating circuit of the rollers (200) being configured so that the circulation of said heat transfer fluid between said laminating stages (10, 20, 30, 40) is opposite to the processing path (L) of the continuous layer (S).

7. A unit (1 ) according to claim 6, when dependent on claim 5, wherein said thermostating circuit of the rollers (200) is configured so as to connect, in parallel, the last laminating stage (40) and the penultimate laminating stage (30) to said thermostating control unit (C), and wherein said thermostating circuit of the rollers (200) is configured so as to mutually connect, in series, the remaining laminating stages (10, 20) arranged upstream of said penultimate laminating stage (30).

8. A unit (1 ) according to any one of the preceding claims 3 to 7, wherein the thermostating circuit of the rollers (200) is configured so as to connect, in series, the laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b) of a same pair of laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b).

9. A unit (1 ) according to claim 8, wherein at least one of the laminating stages (10, 20, 30, 40), preferably all the laminating stages (10, 20, 30, 40), is a horizontal laminating stage comprising a lower roller (10a, 20a, 30a, 40a) and an upper roller (10b, 20b, 30b, 40b); and wherein the thermostating circuit of the rollers (200) is configured so that the upper roller (10b, 20b, 30b, 40b) is connected, in series, downstream of the lower roller (10a, 20a, 30a, 40a).

10. A unit (1 ) according to any one of the preceding claims 3 to 9, wherein said thermostating circuit of the rollers (200) is a closed circuit.

11. A unit (1 ) according to any one of the preceding claims, wherein atleast one laminating roller (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b) of each laminating stage (10, 20, 30, 40) is a motorized laminating roller associated with a respective engine (M) and wherein said thermostating system (100) comprises a thermostating circuit of the engine of the rollers (300); said thermostating circuit of the engine of the rollers (300) being configured to regulate a temperature of the motors and / or reducers of said engines (M).

12. A unit (1 ) according to claim 11 , wherein said thermostating circuit of the engine of the rollers (300) is configured to feed the heat transfer fluid to the engines (M) at a temperature comprised between 5°C and 30°C, preferably comprised between 5°C and 20°C.

13. A unit (1 ) according to claim 11 or 12, wherein said thermostating circuit of the engine of the rollers (300) is configured so as to connect, in parallel, the laminating stages (10, 20, 30, 40).

14. A unit (1 ) according to any one of the preceding claims 11 to 13, wherein each laminating roller (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b) of each pair of laminating rollers is a motorized laminating roller provided with a respective engine (M) and wherein said thermostating circuit of the engine of the rollers (300) is configured so as to connect, in parallel, the engines (M) of the same pair of laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b).

15. A unit (1 ) according to any one of the preceding claims 11 to 14, wherein said thermostating circuit of the engine of the rollers (300) is an open circuit; said thermostating circuit of the engine of the rollers (300) being connected to an external source (A) of heat transfer fluid configured to feed heat transfer fluid into the thermostating circuit of the engine of the rollers (300), and to an external heat transfer fluid discharge (B) configured to discharge used heat transfer fluid from the thermostating circuit of the engine of the rollers (300).

16. A unit (1 ) according to any one of claims 11 to 15, when dependent on claim 3, wherein said thermostating control unit (C) comprises a heattransfer device (101 ) configured to transfer heat between the thermostating circuit of the rollers (200) and the thermostating circuit of the engine of the rollers (300).

17. A unit (1 ) according to claim 16, when dependent on 15, wherein said thermostating circuit of the engine of the rollers (300) comprises at least a first branch (301 ), configured to convey said heat transfer fluid through said engines (M), and at least a second branch (302), parallel to said at least one first branch (301 ), configured to convey said heat transfer fluid through said heat transfer device (101 ); said at least one first branch (301 ) and said second branch (302) having at least one common dividing point (303) arranged upstream of said engines (M) and said heat transfer device (101 ), respectively, and at least one common connecting point (304) located downstream of said engines (M) and said heat transfer device (101 ), respectively.

18. A unit (1 ) according to any one of the preceding claims, wherein said thermostating system (100) comprises a plurality of heat transfer fluid pumping devices and heat transfer fluid flow control devices, such as, for example control valves, and a control unit (U), connected to said control devices and configured to regulate said control devices.

19. A unit (1 ) according to claim 18, wherein said thermostating system comprises a plurality of temperature measuring sensors for the laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b) and / or for the engine (M) of the laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b), connected to said control unit (U) and configured to detect respective temperature values of said laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b) or of the engine (M) of the laminating rollers (10a, 10b, 20a, 20b, 30a, 30b, 40a, 40b); said control unit (U) being configured to command said pumping devices and heat transfer fluid flow control devices as a function of said measurements.

20. A unit (1 ) according to any one of the preceding claims, wherein said thermostating system (100) comprises tubes for conveying the heattransfer fluid from the thermostating control unit (C) to the laminating stages (10, 20, 30, 40) and vice versa, which are arranged and / or configured to be overhead with respect to said laminating stages (10, 20, 30, 40).

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