Mixer and method for making a plant-based mixture in a continuous process

Abstract

A mixer (1) for making a plant-based mixture in a continuous process, comprising a containing frame (2) internally defining a mixing space (V), cylindrical in shape and provided with at least one feed opening (3) and at least one discharge opening (4). The containing frame (2) extends along a main axis (X) having preferably substantially horizontal orientation. The mixer (1) comprises a motor-driven mixing shaft (5), located inside the containing frame (2) and rotatable about the main axis (X) and provided with a plurality of mixing vanes (6) which extend radially away from the mixing shaft (5) and configured so that, in use, they cause the mass of the mixture to be mixed and at the same time progressively to be advanced in one direction from the at least one feed opening (3) towards said at least one discharge opening (4).

Description

[0001] MIXER AND METHOD FOR MAKING A PLANT-BASED MIXTURE IN A CONTINUOUS PROCESS

[0002] Technical field

[0003] The present invention relates to the field of semi-finished products for making smoking articles or for generating aerosols, and the object thereof is a mixer and a method for making a plant-based mixture, in particular dough-like, in a continuous process.

[0004] Background art

[0005] In the present description, the term “plant-based” means that the mixture is obtained from mixing a dry component, such as, for example tobacco or non-tobacco (rapeseed, straw or other varieties, cellulose, or the like), with a liquid component, such as, for example water and / or additives.

[0006] Likewise, the term “dough-like” means a mixture having increased viscosity and a dense and pasty consistency. In particular, this term generally means a mixture with a moisture content of less than 60%.

[0007] In the relevant field of the present invention, it is known to make dough- like mixtures continuously implementing operating mixers.

[0008] Structurally, such a type of mixers comprises a containing frame internally defining a mixing space, cylindrical in shape and having a feed opening and a discharge opening.

[0009] Such a type of mixers comprises a motor-driven mixing shaft located inside the containing frame and rotatable about a main rotation axis. The mixing shaft is provided with a mixing auger configured to cause the mass of mixture to be mixed and at the same time progressively advanced in one direction from the feed opening towards the discharge opening.

[0010] Mixers of such a type are configured to cause the mixture to be extruded from the discharge opening. In particular, under the provided operating conditions, the structure of the mixer (discharge opening, auger) creates a continuous emission of an extruded mixture. Such an extrudate is further processed (rolled, pressed) to make a continuous sheet.

[0011] Although it is operable, the Applicant has found that such a technology has some functional and structural disadvantages and is therefore improvable.

[0012] Firstly, extruding the mixture can cause excessive stress to the mixture itself, especially if the mixture is particularly viscous or contains solid particles. This may result in a loss of quality of the end product or structural imperfections. Further, auger mixers also extruding the mixture are less performing than conventional “batch” vane mixers (i.e., suitable for mixing discrete quantities of mixture) due to the dual extrusion-mixing function requiring a structural compromise on the structure of the auger which, being mainly suitable for the axial thrust, does not allow optimal mixing.

[0013] In such a context, the technical task of the present invention is therefore providing a mixer and a method for making a plant-based mixture, in particular dough-like, in a continuous process which do not have the drawbacks present in the prior art.

[0014] Disclosure of the invention

[0015] It is the object of the present invention to provide a mixer and a method for making a plant-based mixture, in particular dough-like, in a continuous process capable of preserving the properties of the mixture.

[0016] It is the further object of the present invention to provide a mixture and a method for making a plant-based dough-like mixture in a continuous process which allows optimal mixing of the components.

[0017] The above objects are substantially achieved by a mixer and a method according to the features set forth in claims 1 and 10 and / or in one or more of the claims dependent thereon.

[0018] In particular, the Applicant has found that by continuously mixing without extrusion, in particular by means of a mixer provided with mixing vanes, benefits of a conventional mixing process are obtained without the compromises introduced by implementing a mixing auger. The mixing vanes, being configured so as to perform, simultaneously to the mixing, a thrust in one direction of the mixture from the inlet opening to the outlet opening, define also the movement of the mixture simultaneously to the mixing.

[0019] Brief description of drawings

[0020] Further features and advantages of the present invention will become more apparent from the indicative and therefore non-limiting description of a preferred, but not exclusive, embodiment of a method for making a plantbased mixture, in particular dough-like, in a continuous process, as shown in accompanying Figure 1 , which shows a diagrammatic front view of a preferred, exemplary and non-limiting embodiment of a mixer for making a plant-based mixture, in particular dough-like, according to the invention.

[0021] Detailed description of preferred embodiments of the invention

[0022] With reference to the accompanying drawings, reference numeral “1 ” indicates a mixer for implementing a method for making a plant-based mixture, in particular dough-like, according to the invention. Therefore, the method is described below in an embodiment thereof with reference to mixer 1 used for implementing it.

[0023] As will be more apparent in the continuation of the present description, the term “plant-based” means that the mixture is obtained from mixing at least one dry component, such as, for example tobacco or non-tobacco (rapeseed, straw or other varieties, cellulose, or the like), with a liquid component, such as water and / or additives, for example.

[0024] Likewise, the term “dough-like” means a mixture having increased viscosity and a dense and pasty consistency.

[0025] In particular, this term generally means a mixture with a moisture content of less than 60%. Preferably, the mixture is subsequently processed to make a filling material for making smoking articles or for generating aerosols.

[0026] For example, according to a preferred, exemplary and therefore nonlimiting embodiment of the mixture, the mixture comprises a quantity of dry plant material between 40% and 80% of the total weight of the mixture.

[0027] The dry plant material comprises an amount of binding agent comprised between 1% and 20%, preferably between 1% and 10%. Preferably, the binding agent is CMC.

[0028] The dry plant material comprises a quantity of agent for the formation of aerosols between 1% and 30%, preferably between 15% and 25%. The agent for the formation of aerosols may be glycerin-based, preferably it is glycerin or propylene glycol.

[0029] According to the present invention, mixer 1 comprises a containing frame 2 internally defining a cylindrical-shaped mixing space “V”. In particular, the containing frame 2 extends along a main extension axis “X” having substantially horizontal orientation.

[0030] According to an aspect of the present invention, the mixing space “V” has preferably a length / width ratio between 1 .6 and 2.3. Thereby, enough time is ensured for the mixture to remain in the mixing space “V” while the mixture is being continuously mixed.

[0031] The containing frame 2 is provided with at least one feed opening 3 and at least one discharge opening 4.

[0032] According to an aspect of the present invention, the at least one feed opening 3 and the at least one discharge opening 4 are located at opposite ends of the mixing space “V”.

[0033] Preferably, the at least one feed opening 3 is located in an upper region of the containing frame 2 so as to load the components into the mixing space “V” by gravity.

[0034] Further, the at least one discharge opening 4 is preferably located in a lower region of the containing frame 2 and / or on an end wall of the containing frame 2, oriented transversely to the main axis “X”. Figure 1 shows only the case of discharge opening 4 on the lower region of the containing frame 2.

[0035] According to an aspect of the present invention, the discharge opening 4 is configured to define an egress of the mass of the mixture by gravity, in particular without extrusion. In other words, the discharge opening 4 is designed so that the mixture egresses the containing space “V” by means of the simple effect of gravity, without the need to apply an additional mechanical force for pushing or compressing the mixture through the discharge opening 4. This outlet process occurs mainly by gravity without involving extrusion actions which would require an additional pressure or force for pushing the mixture out of mixer 1 . Thereby, it is avoided to use complex components or extrusion systems and a simpler and more controlled egress of the mixture from mixer 1 is allowed.

[0036] In particular, in the case in Figure 1 , the fall by gravity occurs in the instant in which the mixture reaches the discharge opening 4. In the case of discharge opening 4 located on an end wall of the containing frame 2, the mixture could in any case egress frontally without extrusion, for example by simple axial thrust, keeping the irregular shape thereof or the shape in “portions” which are periodically detached from the mixture in the mixing space V .

[0037] Mixer 1 comprises a motor-driven mixing shaft 5 located inside the containing frame 2 and rotatable about the main extension axis “X” of the containing frame 2 itself.

[0038] To this end, the mixer comprises a motor 7 connected to the mixing shaft 5 and a control unit “U” connected to motor 7. Structurally, the mixing shaft 5 is provided with a plurality of mixing vanes 6, separate from one another and connected to the mixing shaft 5, which extend radially away from the mixing shaft 5 and are configured so that, in use, the mixing vanes 6 cause the mass of the mixture to be mixed and at the same time progressively advanced in one direction from the at least one feed opening 3 towards the at least one discharge opening 4. In other words, the mixing vanes 6 are designed so that during operation, they perform two main actions simultaneously: firstly, they uniformly mix the mixture, ensuring all the ingredients are well combined. Secondly, they progressively push the mixture forwards along the mixing space “V” of the containing frame 2, gradually moving from the at least one feed opening 3 towards the discharge opening 4.

[0039] Preferably, mixer 1 comprises between 4 and 8 mixing vanes 6.

[0040] According to an aspect of the present invention, at least one of the mixing vanes 6, preferably each of the mixing vanes 6, makes, with the main axis “X”, an inclination angle different from 90° so that, in use, the mass of the mixture is made to move at least along a direction parallel to the main axis “X”. In other words, the inclination angle of the vanes 6 with respect to the main axis “X” of mixer 1 creates a thrust component along the main axis “X”, thus contributing to moving the mass of the mixture in a direction parallel to the main axis “X” while the mixing process occurs. This feature optimizes the mixing and moving process of the mixture in mixer 1 .

[0041] According to an aspect of the present invention, at least one of the mixing vanes 6, preferably each of the mixing vanes 6, is positioned at a distance from the containing frame 2 such as to create, in use, a mechanical action for scraping the mass of the mixture off the containing frame 2. In other words, the mixing vanes 6 are configured so as to cause a detachment of the mixture adhering to the inner surfaces of the containing frame 2 so as to move it radially towards the main axis “X” of mixer 1 and mix it with the remaining mass of the mixture.

[0042] According to an aspect of the present invention, the mixing vanes 6 are distributed axially along the mixing shaft 5, preferably helically distributed or distributed according to two or more rows parallel to the main axis “X”. This arrangement of the vanes 6 contributes to ensuring an effective and uniform mixing of the mixture since the vanes 6 work synergistically during the rotation of the mixing shaft 5, contributing to efficiently moving and mixing the mixture along the mixing space “V” of mixer 1 . Figure 1 shows a solution in which the mixing shaft 5 has three mixing vanes 6 distributed in diametrically opposite position from one another and in successive positions along the main axis “X”. However, it is apparent that the number and distribution of the vanes 6 can be different.

[0043] The containing frame 2 can comprise a stratified cooling jacket (not shown in the accompanying drawings) configured to keep the mixing space “V” at a predetermined temperature during the operating steps of mixer 1. In particular, with reference to a radial direction with respect to the aforesaid main extension axis “X” (in particular, from the inside of the containing frame 2 towards the outside of the containing frame 2), the containing frame has inner walls (delimiting and defining the aforesaid mixing space “V”), an insulating gap and outer containing walls. Preferably, the insulating gap comprises at least one insulation layer, for example rock wool and / or a fluid cooling circuit, a water cooling circuit for example.

[0044] The aforesaid method for making a plant-based mixture, in particular dough-like, according to the present invention is implementable by means of mixer 1 described.

[0045] The method provides feeding a first quantity of at least one dry, ground and / or powdered product into the mixing space “V” of mixer 1 through the feed opening 3 continuously or in successive steps. In other words, the method provides introducing a first quantity of at least one dry, ground and / or powdered material into the mixing space “V” of mixer 1 continuously or in successive steps using the specific feed opening 3. The definition of “first quantity” means that it is possible to introduce into the mixing space “V” a specific dry, ground and / or powdered material, a premixed mixture of different dry, ground and / or powdered materials, or several dry, ground and / or powdered materials which were not previously mixed with one another.

[0046] The method provides feeding a second quantity of at least one liquid into the mixing space “V” of mixer 1 through said at least one feed opening 3, in particular through the same feed opening used for the dry step or through a separate feed opening, continuously or in successive steps. In other words, the process provides introducing a second quantity of at least one liquid into the mixing space “V” of the mixer using at least one of the specific feed openings 3, continuously or in successive steps. The definition of “second quantity” means that it is possible to add into the mixing space “V” a single liquid, a mixture of liquids, or several different liquids which were not previously mixed with one another.

[0047] The method then provides mixing the first quantity of dry product with the second quantity of liquid to obtain a mixture: the mixing step is operated by means of the mixing shaft 5, and in particular, by means of the mechanical action of the plurality of mixing vanes 6. In particular, during the mixing step, the mass of the mixture is conveyed progressively and in one direction towards the at least one discharge opening 4 of mixer 1 .

[0048] According to an aspect of the present invention, during the mixing, the mixing vanes 6 create a scraping action whereby the mass of the mixture is scraped off the containing frame 2. In other words, the vanes 6 detach the mass of the mixture adhering to the walls of the containing frame 2 and remix it with the remaining mass of the mixture. The scraping ensures the mixture is continuously mixed and that all the ingredients are involved in the mixing process, thus contributing to obtaining uniform results in the production of food products.

[0049] The method then provides a step in which the mixture is discharged by means of the at least one discharge opening 4.

[0050] According to an aspect of the present invention, the step of discharging the mixture is performed without extruding the mixture. Preferably, the mixture is discharged by gravity (below and / or frontally) from the at least one discharge opening 4.

[0051] The present invention achieves the intended purposes by eliminating the drawbacks highlighted in the prior art.

[0052] In this regard, it is worth noting that mixer 1 thus described and / or claimed has a structure capable of preserving the physical properties of the mixture. Such a result is achieved by implementing mixing vanes 6 in synergy with discharging the mixture without extruding the mixture.

[0053] The implementation of a discharge without extruding, as the implementation of the aforesaid mixing vanes 6, further allows mixer 1 to be highly effective by optimally mixing the components. The vane structure indeed can be optimized for mixing components and its further function of axial thrust in one direction of the mixture towards the discharge opening is a contrivance that does not alter the mixing efficiency. Further, with a discharge by gravity, there is no need to have a mixture with specific physical properties (such as consistency, elasticity, viscosity or hydration, for example) for the extrusion or to have specific operating conditions (such as the discharge speed or discharge pressure, for example) for the extrusion. In the same way, the vanes 6 require a range of specific physical properties of the mixture and / or a less stringent range of the operating conditions.

[0054] Lastly, the implementation of a discharge without extruding, as well as the implementation of the aforesaid mixing vanes 6, allows the operating and management costs of the system to be reduced. Indeed, the discharge opening, being configured to define an egress of the mass of the mixture by gravity, tends to be less subject to wear and more easily serviceable.

Claims

CLAIMS1. A mixer (1 ) for making a plant-based mixture in a continuous process, configured to operate continuously and comprising:- a containing frame (2) internally defining a mixing space (V), cylindrical in shape and provided with at least one feed opening (3) and at least one discharge opening (4); said containing frame (2) extending along a main axis (X) preferably having a substantially horizontal orientation;- a motor-driven mixing shaft (5), located inside the containing frame (2) and rotatable about said main axis (X); said mixing shaft (5) being provided with a plurality of mixing vanes (6) which extend radially away from the mixing shaft (5) and are configured so that, in use, said mixing vanes (6) cause the mass of the mixture to be mixed and at the same time progressively advanced in one direction from the at least one feed opening (3) towards said at least one discharge opening (4).

2. The mixer (1 ) according to claim 1 , wherein at least one of said mixing vanes (6), preferably each of said mixing vanes (6), makes with said main axis (X) an inclination angle different from 90° so that, in use, the mass of the mixture is made to move at least along a direction parallel to the main axis (X).

3. The mixer (1 ) according to claim 1 or 2, wherein at least one of said mixing vanes (6), preferably each of said mixing vanes (6), is positioned at a distance from the containing frame (2) such as to create, in use, a mechanical action for scraping the mass of the mixture off the containing frame (2).

4. The mixer (1 ) according to any one of the preceding claims, wherein said mixing vanes (6) are distributed axially along said mixing shaft (5), preferably helically distributed.

5. The mixer (1 ) according to any one of the preceding claims, wherein said mixing shaft (5) has two or more aggregates of mixing vanes (6), said aggregates distributed angularly around the main axis (X); each aggregate comprising two or more mixing vanes (6) distributed axially along saidmain axis (X).

6. The mixer (1 ) according to any one of the preceding claims, wherein said discharge opening (4) is configured to define an egress of the mass of the mixture by gravity, in particular without extrusion.

7. The mixer (1 ) according to any one of the preceding claims, wherein said mixing space (V) has a length / width ratio between 1 .6 and 2.3.

8. The mixer (1 ) according to any one of the preceding claims, wherein said at least one feed opening (3) and said at least one discharge opening (4) are located at opposite ends of the mixing space (V), preferably the at least one feed opening (3) being located in an upper region of the containing frame (2), and the at least one discharge opening (4) being located in a lower region of the containing frame (2) and / or on an end wall of the containing frame (2), oriented transversely to the main axis (X).

9. The mixer (1 ) according to any one of the preceding claims, configured for working on a plant-based mixture having a moisture content of less than 60% by weight, in particular a dough-like mixture.

10. A method for making a plant-based mixture continuously in a continuous process, in particular implemented by a mixer (1 ) 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 into the mixing space (V) of a mixer (1 ) through at least one feed opening (3), continuously or in successive steps;- feeding a second quantity of at least one liquid into the mixing space (V) of the mixer (1 ) through said at least one feed opening (3), continuously or in successive steps;- mixing the first quantity of dry product with the second quantity of liquid to obtain a mixture via a mixing shaft (5) provided with a plurality of mixing vanes (6) which extend radially away from the mixing shaft (5); wherein, in said step of mixing, the mass of the mixture is conveyed by said vanes (6) progressively and in one direction towards the at least one discharge opening (4) of the mixer (1 );- discharging said mixture from the mixer (1 ) through said at least one discharge opening (4).

11. The method according to claim 10, wherein said step of discharging the mixture is carried out without extruding the mixture.

12. The method according to claim 10 or 11 , wherein said mixture is discharged from said at least one discharge opening (4) by gravity.

13. The method according to any one of preceding claims 10 to 12, wherein, in said step of mixing, said mixing vanes (6) create a scraping action whereby the mass of the mixture is scraped off the containing frame (2).

14. The method according to any one of preceding claims 11 to 13, wherein said mixture has a moisture content of less than 60% by weight and is, in particular, a dough-like mixture.

15. The method according to any one of preceding claims 11 to 14, wherein the mixture is subsequently processed to make a filling material for making smoking articles or for generating aerosols.

16. The method according to claim 15, wherein the dry and / or powdered product is selected among tobacco, rapeseed, straw, cellulose and / or another non-tobacco material for making smoking articles or for generating aerosols.

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