Kneader and method for making a plant-based mixture

Abstract

A kneader (100) for making a plant-based mixture (I) is configured to work in batches and comprises a containing frame (101), which internally defines a cylindrical mixing space (V), a motor-driven kneading shaft (104) configured for mixing the mixture (I) and disposed inside the containing frame (101). The kneader (100) comprises a fluid circuit (105) for controlling the temperature, disposed around the mixing space (V) and configured to affect the temperature of the mixing material inside the mixing space (V) at least during an operating step of the kneader (100).

Description

[0001] DESCRIPTION

[0002] KNEADER AND METHOD FOR MAKING A PLANT-BASED MIXTURE

[0003] Technical field

[0004] This invention relates to the smoking article industry and has for an object a kneader, a plant comprising such a kneader and a method for making a plant-based mixture.

[0005] Background art

[0006] In this disclosure, the expression "plant-based" is used to mean that the mixture is obtained by mixing a dry plant component such as, for example, tobacco or non-tobacco (rapeseed, straw or other plant varieties, cellulose or the like) and a liquid component, such as water and / or additives.

[0007] In the field relevant to this invention, the prior art teaches making mixtures using kneaders comprising a containing frame which internally define a cylindrical mixing space provided with a feed opening and a discharge opening. Typically, kneaders of this kind have a containing frame which extends horizontally.

[0008] These kneaders comprise a motor-driven kneading shaft disposed inside the containing frame and rotatable about the axis of extension of the containing frame. Structurally, the kneading shaft is provided with at least one mixing vane or with a screw extending transversely to the kneading shaft. As is known, the kneading shaft is configured to be driven to mix the components to obtain a smooth mixture.

[0009] The Applicant has found that this technology, although well operable, can be improved.

[0010] As a result of the mechanical friction created during mixing (in particular, the friction between the ingredients of the mixture as well as between the ingredients and the wall of the container), combined with the mixing speed, the duration of mixing and / or the composition of the ingredients, undesirable heat is generated inside the mixing space, leading to an increase in the temperature of the mixture.

[0011] Excessive heating may lead to undesirable change in the composition (in particular, the chemical composition) of the mixture, affecting the yield and quality of the final product. Excessively high temperature may also have a negative effect on the consistency and quality of the mixture, impacting adversely on the desired properties of the final product.

[0012] Moreover, there may be situations where, on the contrary, the mixture needs to be mixed at a temperature which is different from ambient temperature.

[0013] Aim of the invention

[0014] The principal aim of this invention is to provide a kneader, a plant comprising such a kneader and a method for making a plant-based mixture, capable of ensuring precise temperature control during the mixing process in order to prevent excessive heating and undesirable changes in the chemical composition of the mixture, or processing at a predetermined temperature. Another aim of this invention is to provide a kneader, a plant comprising such a kneader and a method for making a plant-based mixture, where the aforesaid temperature control does not excessively impact the structure and / or operation of the kneader.

[0015] The technical purpose and aims specified are substantially achieved by a kneader, a plant comprising such a kneader and a method for making a plant-based mixture, comprising the technical features set out in the appended claims 1 , 8 and 9, respectively, and / or in one or more of the claims dependent thereon and / or in the accompanying description.

[0016] The Applicant has found that controlling the temperature using a fluid circuit disposed around the mixing space of the kneader, where the fluid circuit is configured to affect the temperature of the mixing material inside the mixing space at least during an operating stage of the kneader, allows optimum temperature control and management, thus ensuring the production of a high-quality mixture. Brief description of the drawings

[0017] Further features and advantages of this invention are more apparent in the exemplary, hence non-limiting description of an embodiment of a plant comprising such a kneader and a method for making a plant-based mixture, as illustrated in the accompanying drawings, in which:

[0018] - Figure 1 shows a schematic view of an exemplary, non-limiting, preferred embodiment of a plant according to the invention, for making a web of plantbased reconstituted material;

[0019] - Figure 2 shows a detail of an exemplary, non-limiting, preferred embodiment of a kneader according to this invention, the kneader being a part of the plant of Figure 1 .

[0020] Detailed description of preferred embodiments of the invention

[0021] With reference to the accompanying drawings, the reference numeral 1 denotes in its entirety a plant for making a web N of plant-based reconstituted material according to this invention. The expression "plantbased" is used to mean that the web N is obtained by processing at least one dry plant component such as, for example, tobacco or non-tobacco (rapeseed, hemp, straw or other plant varieties, cellulose or cellulose derivates) mixed with at least one liquid component, such as water and / or additives, for example.

[0022] The reference numeral 100, on the other hand, denotes a kneader according to this invention, for making a plant-based mixture I using at least one dry plant component and the at least one liquid component. The kneader 100 is a part of the aforesaid plant 1 .

[0023] The invention also relates to a method for making a plant-based mixture, preferably using the kneader 100. Hereinafter in this description, therefore, the method is described with reference to the kneader 100 used to make it. As may be seen in Figure 1 , the plant 1 comprises a feed unit 2 configured for feeding at least one dry, plant-based material in ground and / or powdered form, and at least one liquid.

[0024] The feed unit 2 is of a conventional type which is well known in the industry relevant to this invention, and it is not therefore described in detail because its structure and functionality are both commonly known and documented in the prior art.

[0025] Preferably, the feed unit 2 comprises one or more feed branches 2a, 2b for feeding respective solid and / or liquid components.

[0026] Downstream of the feed unit 2, the plant 1 comprises the kneader 100, configured for receiving the at least one solid component and the at least one liquid from the feed unit 2 and for making a mixture I by mixing them together.

[0027] According to the invention, the kneader 100 is configured to work in batches. The expression "in batches" is used to mean that the entire process is performed in discrete lots or defined portions. In other words, production occurs in distinct steps and each step involves a specific quantity of raw materials. That translates as specific structural features of the kneader 100, as will become apparent as this description continues.

[0028] Preferably, the kneader 100 is configured for making a mixture I having a moisture content of less than 60% by weight, in particular a dough-like mixture, that is to say, a mixture having a pasty or viscous consistency, more specifically making it malleable.

[0029] Downstream of the kneader 100, the plant 1 comprises a laminating unit 3 comprising at least one pair of rollers configured to receive the mixture I leaving the kneader 100 and to laminate said mixture I into a continuous layer S having a calibrated thickness. Like the feed unit 2, the laminating unit 3 is of a conventional type which is well known in the industry relevant to this invention, and it is not therefore described in detail.

[0030] For example, the laminating unit 3 may comprise a plurality of laminating stages 3a, 3b disposed in succession and configured to first of all form the continuous layer S and then to gradually reduce the thickness of the layer S of material. Each laminating stage 3a, 3b comprises a respective pair of opposing rollers. Depending on the specific requirements of the application or of the product to be made, the laminating stages 3a, 3b may be configured to perform a vertical lamination and / or a horizontal lamination of the product.

[0031] Lastly, downstream of the laminating unit 3, the plant 1 comprises a drying unit 4 configured to dry the layer S to obtain the aforesaid web N of plantbased reconstituted material.

[0032] Hereinafter, with reference to Figures 1 and 2, a preferred embodiment of the kneader 100 is described by way of non-limiting example.

[0033] The kneader 100 comprises a containing frame 101 internally defining a mixing space V, cylindrical in shape and provided with at least one feed opening 102 and at least one discharge opening 103.

[0034] Preferably, the feed opening 102 is made in an upper portion of the containing frame 101 .

[0035] Preferably, the discharge opening 103 is made in a lower portion of the containing frame 101 .

[0036] Preferably, the discharge opening 103 is defined by a bottom hatch, in particular provided with a hinged door and / or having a curvature which exactly matches the curvature of the entire mixing space V.

[0037] Advantageously, such a structure allows discharging all of the mixture all at once, in particular by gravity.

[0038] The containing frame 101 extends along a main axis X preferably having a substantially horizontal orientation.

[0039] The kneader 100 comprises a motor-driven kneading shaft 104 configured for mixing the mixture I. The kneading shaft 104 is disposed inside the containing frame 101 and is rotatable about the main axis X.

[0040] Preferably, the kneading shaft 104 is provided with a plurality of mixing blades 1 10 which extend radially away from the kneading shaft 104 and which are illustrated schematically in Figure 1 . With reference to the conformation of the individual blades 1 10, according to the general nature of the invention, the length, profile and / or inclination of the blades 1 10 are optimized as a function of the specific composition of the mixture to be processed.

[0041] Preferably, each blade 1 10 has a conformation which is elongated along a direction radially away from the kneading shaft 104.

[0042] Preferably, each blade 1 10 is twisted in profile and / or inclined to the main axis X so that the mixture is moved along a direction parallel to the main axis X and / or transverse to the main axis X (that is, towards / away from the kneading shaft 104 itself).

[0043] Each blade 110 may also have a substantially uniform profile or a hammer profile.

[0044] With reference to the distribution of the blades 1 10, according to the general nature of the invention, the blades 1 10 may be distributed individually along the kneading shaft 104 or they may be arranged in groups on the kneading shaft 104 as a function of the specific composition of the mixture to be processed.

[0045] In the example illustrated in Figure 1 , the blades 110 are distributed along the kneading shaft 104 in such a way as to be angularly disposed on the kneading shaft 104 alternately at 180° from each other.

[0046] In an example, the blades 1 10 are grouped together in pairs which are angularly disposed on the kneading shaft 104 at 180° from each other.

[0047] According to the general nature of the invention, other configurations are also contemplated, where the blades 1 10 are arranged on the kneading shaft 104 in groups of different numbers.

[0048] At a functional level, the method according to this invention comprises feeding a first quantity of at least one dry, ground and / or powdered product through at least one feed opening 102 into the mixing space V defined by the containing frame 101 of the kneader 100.

[0049] Next, a second quantity of at least one liquid is fed into the mixing space V through the at least one feed opening 102. The first quantity of dry product is then mixed with the second quantity of liquid by the kneading shaft 104 to obtain the aforesaid mixture I. Preferably, the mixing of the mixture I in the mixing space V is performed by the plurality of mixing blades.

[0050] Lastly, the mixture I is discharged from the kneader 100 through the at least one discharge opening 103. The mixture I is then sent to the processing units downstream.

[0051] According to the invention, the containing frame 101 of the kneader 100 comprises a fluid circuit 105 for controlling the temperature, disposed around the mixing space V and configured to affect the temperature of the mixing material inside the mixing space V at least during an operating step of the kneader 100. In other words, during the step of mixing, there is a step of exchanging heat between the mixture I being processed in the mixing space V and a fluid circuit 105 disposed around the mixing space V.

[0052] Preferably, the fluid circuit 105 is a cooling circuit. That means its main function is to reduce the temperature of the mixture I inside the mixing space V by extracting heat from it. Heat exchange therefore consists in extracting heat by means of the aforesaid fluid circuit 105.

[0053] In a particularly advantageous embodiment, the fluid circuit 105 works using water.

[0054] In other embodiments, the fluid circuit may work using alterative fluids such as, for example, ethylene glycol, propylene glycol, thermal oils or synthetic refrigerant fluids, depending on specific process requirements.

[0055] As shown in Figure 2, the containing frame 101 preferably has an inside wall 106 and an outside wall 107 extending around the main axis X and delimiting, between them, a gap 108 in which the fluid circuit 105 is at least partly disposed. In other words, at a functional level, at least during the step of mixing, the fluid of the fluid circuit 105 flows in the gap 108 so as to perform the aforesaid heat exchange with the mixture I inside the mixing space V. Preferably, the containing frame 101 also comprises at least one insulating layer 109, disposed outside the fluid circuit 105 and at least partly covering the fluid circuit 105, in particular adjacent to said outside wall 107, so as to inhibit or limit heat exchange between the fluid circuit 105 and an external environment E outside the kneader 100.

[0056] Preferably, the at least one insulating layer 109 is made from a heat insulating material, preferably a traditional insulating material, an advanced inorganic insulating material, a thermoplastic foam and / or a composite material.

[0057] Preferably, the kneader 100 comprises at least one temperature sensor (not illustrated), configured to detect a temperature inside the mixing space V and to generate an identifier signal representing the temperature, and a control unit U connected to the at least one sensor and to the fluid circuit 105: the control unit U is configured to receive and process the identifier signal from the at least one sensor and to command the fluid circuit 105 as a function of the identifier signal and of a predetermined temperature value. In other words, at a functional level, the extraction of thermal energy is regulated by the control unit U as a function of an effective value of temperature detected inside the mixing space V via the at least one temperature sensor and as a function of the predetermined temperature value.

[0058] In this description, "predetermined temperature value" can mean an optimum mixing temperature, that is, an ideal temperature at which the dry and liquid ingredients should be mixed to obtain the best organoleptic, structural and consistency properties of the mixture I. In other words, keeping the temperature close to this optimum value ensures as far as possible that the final product has the desired properties.

[0059] Alternatively, "predetermined temperature value" can mean a limit temperature above which the mixture I deteriorates, that is to say, a critical threshold value which, if exceeded, cause the properties of the mixture I to start deteriorating. In this case, the function of the control unit U and of the fluid circuit 105 is to prevent the temperature inside the kneader 100 from exceeding the critical value.

[0060] Preferably, the kneader 100 comprises a user interface device (not illustrated) connected to the control unit U and configured to receive as input the aforesaid predetermined value and to transmit it to the control unit U. According to a first, particularly advantageous (but non-limiting) operating logic, the fluid circuit 105 is configured to maintain a constant effective temperature measured inside the mixing space V. In other words, the fluid circuit 105 may be remain on not only during the active mixing step (that is, while the batches are being produced) but also during the intermediate step between two consecutive batches.

[0061] According to a second, particularly advantageous (but non-limiting) operating logic, the fluid circuit 105 may be configured to operate on an on / off basis. For example, during the active mixing step of one batch, the fluid circuit 105 could be turned on to maintain the desired temperature. When the step of mixing that particular batch is over, the fluid circuit 105 could be turned off until the beginning of the next batch.

[0062] In another example, on completion of each batch, the fluid circuit 105 could be turned on to reduce the effective temperature value inside the mixing space V before the next batch starts so that production of the next batch starts when the temperature has already reached the aforesaid predetermined value.

[0063] In another example, the fluid circuit 105 can be controlled dynamically by the control unit U as a function of the difference between the predetermined temperature value and the effective value of the temperature measured inside the mixing space V.

[0064] Preferably, the mixture being mixed is kept at a temperature between 30° and 60°. In an example embodiment, the mixture being mixed is kept at a temperature between 33° and 45°. In a different example embodiment, the mixture being mixed is kept at a temperature less than or equal to 55°. The invention achieves the preset aims overcoming the drawbacks of the prior art.

[0065] In particular, controlling the temperature using a fluid circuit disposed around the mixing space of the kneader allows optimum control and management of mixture temperature so as to ensure production of a high- quality product. This result is achieved thanks to the possibility of extracting heat from the mixing space using the aforesaid fluid circuit in such a way as to control and manage the temperature of the mixture.

Claims

CLAIMS1. A kneader (100) for making a plant-based mixture (I), configured to work in batches and comprising:- a containing frame (101 ) internally defining a mixing space (V), cylindrical in shape and provided with at least one feed opening (102) and at least one discharge opening (103); said containing frame (101 ) extending along a main axis (X) preferably having a substantially horizontal orientation;- a motor-driven kneading shaft (104) configured for mixing the mixture (I); said kneading shaft (104) being disposed inside the containing frame (101 ) and being rotatable about said main axis (X); characterized in that said containing frame (101 ) comprises a fluid circuit (105) for controlling the temperature, disposed around the mixing space (V) and configured to affect the temperature of the mixing material inside the mixing space (V) at least during an operating step of the kneader (100).

2. The kneader (100) according to claim 1 , wherein said fluid circuit (105) is a cooling circuit.

3. The kneader (100) according to claim 1 or 2, comprising:- at least one temperature sensor, configured to detect a temperature inside the mixing space (V) and to generate an identifier signal representing said temperature;- a control unit (U), connected to said at least one sensor and to said fluid circuit (105), said control unit (U) being configured to receive and process the identifier signal from the at least one sensor and to command the fluid circuit (105) as a function of said identifier signal and of a predetermined temperature value.

4. The kneader (100) according to any one of the preceding claims, wherein said containing frame (101 ) has an inside wall (106) and an outside wall (107) extending around said main axis (X) and delimiting, between them, a gap (108) in which said fluid circuit (105) is at least partly disposed.

5. The kneader (100) according to any one of the preceding claims, wherein the containing frame (101 ) comprises at least one insulating layer (109),disposed outside the fluid circuit (105) and at least partly covering the fluid circuit (105), in particular adjacent to said outside wall (107), so as to inhibit or limit heat exchange between the fluid circuit (105) and an external environment (E) outside the kneader (100); said at least one insulating layer (109) being made from a heat insulating material, preferably a traditional insulating material, an advanced inorganic insulating material, a thermoplastic foam and / or a composite material.

6. The kneader (100) according to any one of the preceding claims, wherein said kneading shaft (104) is provided with a plurality of mixing blades (1 10) which extend radially away from the kneading shaft (104).

7. The kneader (100) according to any one of the preceding claims, configured for working on a plant-based mixture (I) having a moisture content of less than 60% by weight, in particular a dough-like mixture (I).

8. A plant (1 ) for the production of a web (N) of reconstituted plant-based material, comprising:- a feed unit (2) configured for feeding at least one dry, plant-based material in ground and / or powdered form, and at least one liquid;- a kneader (100) according to any one of the preceding claims, configured for receiving said at least one solid component and said at least one liquid from the feed means and making a mixture (I) having a moisture content of less than 60% by weight, in particular a dough-like mixture (I);- a laminating unit (3), located downstream of the kneader (100) and comprising at least one pair of rollers configured to receive the mixture (I) leaving the kneader and to laminate said mixture (I) into a continuous layer (S) having a calibrated thickness;- a drying unit (4) for drying said continuous layer (S).

9. A method for making a batch of a plant-based mixture, in particular made using a kneader (100) according to any one of the preceding claims, comprising the following steps:- feeding a first quantity of at least one dry, ground and / or powdered product through at least one feed opening (102) into a mixing space (V) defined bya containing frame (101 ) of a kneader (100);- feeding a second quantity of at least one liquid into the mixing space (V) of the kneader (100) through said at least one feed opening (102);- mixing the first quantity of dry product with the second quantity of liquid via a kneading shaft (104) to obtain a mixture (I);- discharging said mixture (I) from the kneader (100) through said at least one discharge opening (103); characterized in that it comprises, during the step of mixing, a step of exchanging heat between the mixture (I) being processed in the mixing space (V) and a fluid circuit (105) disposed around the mixing space (V).

10. The method according to claim 9, wherein the fluid circuit (105) is a cooling circuit and wherein said step of exchanging heat is done by extracting heat through said cooling circuit.11 . The method according to claim 9 or 10, wherein the extraction of thermal energy is regulated by a control unit (U) as a function of an effective value of temperature detected inside the mixing space (V) via at least one temperature sensor and as a function of a predetermined temperature value.

12. The method according to any one of claims 9 to 1 1 , wherein, at least during the step of mixing, the fluid in the circuit (105) flows in a gap (108) made in the containing frame (101 ) of the kneader (100) and running around the mixing space (V).

13. The method according to any one of claims 9 to 12, wherein heat exchange between the fluid circuit (105) and an external environment (E) outside the kneader (100) is inhibited or limited by at least one insulating layer (109) disposed outside the fluid circuit (105).

14. The method according to any one of claims 9 to 13, wherein the step of mixing the mixture (I) in the containing space (V) is carried out by a kneading shaft (104) provided with a plurality of mixing blades (110) which extend radially away from the kneading shaft (104).

15. The method according to any one of claims 9 to 14, wherein said mixture(I) has a moisture content of less than 60% by weight and is, in particular, a dough-like mixture (I), the method further comprising, after the step of discharging the mixture (I) from the kneader (100) through the at least one discharge opening (103), the step of laminating said mixture (I) into a continuous layer (S) having a calibrated thickness.

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