EP3473111A1

EP3473111A1 - Crimping unit

Info

Publication number: EP3473111A1
Application number: EP18200609.8A
Authority: EP
Inventors: Nicola Baldanza; Massimo Sartoni; Luca Federici
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 2017-10-18
Filing date: 2018-10-16
Publication date: 2019-04-24
Anticipated expiration: 2038-10-16
Also published as: EP3473111B1; PL3473111T3; IT201700117804A1

Abstract

This invention relates to a crimping unit (1) for crimping a web (100) of material used to make tobacco industry products, comprising: - a crimping station (20) having a first crimping roller (21) and a second crimping roller (22) operatively coupled to make a plurality of longitudinal easy folding lines on the web of material (100); - a gathering station (30) comprising a shaping duct (32a) configured to receive the web of material (100) and progressively gather it in order to give it a substantially cylindrical shape. The crimping unit (1) also comprises pneumatic, conveying and cooling means associated with the shaping duct (32a) to convey and cool the web of material (100) as it traverses the shaping duct (32a) through flows of a pressurized fluid which act on the shaping duct (32a) in between its inside surface and the web (100). [Figure 1]

Description

This invention relates to a machine for crimping a web of material used to make tobacco industry products. In particular, this web can be used in the tobacco industry to make traditional filter cigarettes, that is, cigarettes which can be smoked by burning the end of the cigarette opposite the filter, or electronic cigarettes such as, for example: heat not burn, electronic-cig, mixed electronic-cig and tobacco.
Known in the art are crimping systems, as described in document WO 2016/071267 A1 , designed to create corrugations on the web which can subsequently be compacted to create a longitudinal stream containing the crimped web; it was found, however, that the articles made according to this solution are not uniformly compacted but tend to become loose.
The Applicant has found that the articles obtained according to the teachings of the prior art are not optimally compacted and tend to loosen up when subjected to subsequent processes. As a result, the end products may also be non-uniform and of poor quality.
This problem is felt particularly strongly in cases where processing includes reducing the diameter size of the web of material which is used to make the tobacco industry products and which is fed to the different stations along the processing line.
For example in all those processes where the web of material is crimped and then reduced in size until it forms a stream of material with a substantially cylindrical or tubular shape.
In effect, during such processes, the web of material, may be subjected to mechanical stresses which tend to raise its temperature, creating the risk of structurally damaging the web and thus negatively affecting the tobacco industry product to be made.
In this context, the technical purpose which forms the basis of the present invention is to propose a crimping unit which overcomes at least some of the above mentioned disadvantages of the prior art.
More specifically, this invention has for an aim to provide a crimping unit capable of maintaining the operating temperature within acceptable limits during the process of gathering a web of material.
The technical purpose indicated and the aims specified are substantially achieved by a crimping unit comprising the technical features described in one or more of the accompanying claims.
This invention discloses a crimping unit for crimping a web of material used to make tobacco industry products, comprising:

a crimping station having a first crimping roller and a second crimping roller operatively coupled to make a plurality of longitudinal easy folding lines on the web of material;
a gathering station comprising a shaping duct configured to receive the web of material and progressively gather it in order to give it a substantially cylindrical shape.

The crimping unit also comprises pneumatic, conveying and cooling means associated with the shaping duct to convey and cool the web of material as it traverses the shaping duct through flows of a pressurized fluid which act on the shaping duct in between its inside surface and the web.
This feature allows keeping the temperature inside the shaping duct at an ideal level, thus preventing the temperature from reaching excessively high levels which would damage the web of material.
The dependent claims, which are incorporated herein by reference, correspond to different embodiments of the invention.
Further features and advantages of the present invention are more apparent in the detailed description below, with reference to a preferred, but non-exclusive, embodiment of a crimping unit, as illustrated in the accompanying drawings, in which:

Figure 1 is a perspective view of the crimping unit according to this invention;
Figure 2 is a detail view showing a part of the gathering station;
Figure 3 is a cross-section of the part shown in Figure 2;
Figure 3a shows a detail from Figure 3;
Figure 4 is a perspective view of some components of the gathering unit.

With reference to the accompanying drawings, the numeral 1 denotes a crimping unit in its entirety, hereinafter referred to simply as unit 1.
The unit 1 comprises a feed station 10 configured to feed to the crimping unit 1 a web 100 of material of the tobacco industry, a crimping station 20 equipped with crimping rollers 21, 22 and a gathering station 30 located downstream of the crimping station 20.
The unit 1 comprises feed means 11 for feeding the web 100 of material for the tobacco industry, for example of tobacco based material, filter paper or PLA.
The web 100 is adapted to be unwound along a longitudinal feed direction, indicated by the arrow "A" in Figure 1.
Together with the feed means 11, the machine 1 preferably also comprises one or more systems for adjusting the tension of the web 100 (for example, an unwinding feedback sensor) and/or one or more systems for centring the web 100.
To ensure the web 100 is correctly transferred to the further processing stations of the unit 1, the feed means 11, too, are equipped with tensioning devices 12 for tensioning the web 100, embodied for example by dancer rollers.
The feed station 10 comprises at least one infeed diverting roller 13 mounted on a movable supporting device 13a.
The movable supporting device 13a is configured to move the infeed diverting roller 13 along a predetermined path "B" in such a way as to vary the infeed position of the web in the crimping station 20, specifically varying the orientation of the web being fed to the crimping rollers 21, 22.
The path "B" is preferably straight and the movable supporting device 13a comprises a carriage which mounts the diverting roller 13 and which is movable along a respective straight guide, for example disposed vertically in such a way as to define a substantially vertical path "B".
The presence of the at least one diverting roller 13 thus makes it possible, also in use, to modulate the angular portion of the crimping rollers 21, 22 intercepted by the web 100, in particular when entering the crimping station 20, thus helping to lengthen/shorten the stretch of path which the web 100 travels in contact with the surface of the crimping rollers 21, 22.
The crimping station 20 comprises a first crimping roller 21 and a second crimping roller 22 operatively coupled to make a plurality of longitudinal easy folding lines on the web 100 in transit between the two crimping rollers 21, 22.
The crimping rollers 21, 22 have a wavy profile, with respective protrusions and recesses, configured to condition the material in such a way as to make easy folding lines at each interface between protrusion and recess of the two crimping rollers 21, 22.
Advantageously, the crimping station comprises a supporting element 23 for supporting the crimping rollers 21, 22 and configured to adopt variable position and/or orientation in such a way as to vary the geometry of the path followed by the web 100 in the crimping station 20; the supporting element 23 thus comprises motor means 23b acting on the supporting element 23 to vary the position and/or orientation of the supporting element 23.
In other words, the supporting element is movable in such a way as to be able to modify the arrangement of the crimping rollers 21, 22 associated therewith, changing their arrangement within the crimping unit 1 so as to make the web 100 follow a different path defined by the specific arrangement adopted by the crimping rollers 21, 22.
In a preferred embodiment, the supporting element 23 is rotatable about an axis of adjustment "X" to allow turning the crimping station 20 in such a way as to modify, by increasing or decreasing, the winding angle of the web 100 on the first and/or the second crimping roller 21, 22.
Preferably, the supporting element 23 is embodied by a vertical plate 23a which is supported rotatably about the axis of adjustment "X".
Also in this preferred embodiment, the first crimping roller 21 is supported by the supporting element 23 and is connected thereto at its centre of rotation, while the second crimping roller 22 is supported by the supporting element 23 and connected thereto in a zone outside its centre of rotation.
In other words, the axis of rotation of the first crimping roller 21 is coaxial with the axis of adjustment "X", while the axis of rotation "Y" of the second crimping roller 22 is eccentric relative to the axis of adjustment "X".
Thus, during rotation of the supporting element 23, the position of the first crimping roller 21 remains substantially unchanged, while the second crimping roller 22 performs a movement of revolution around the first crimping roller 21.
The supporting element 23 is rotatably supported at a peripheral portion by means of a curved guide which extends around at least one stretch of a circle concentric with the axis of adjustment "X".
The curved guide can define a closed path or, alternatively, an open stretch, depending on the range of angular adjustment around the axis of adjustment "X".
The supporting element 23 also comprises guide means, such as, for example, roller pairs, sliders or other, which are slidably engaged on the curved guide.
The supporting element 23 also comprises motor means, preferably embodied by a rack and pinion drive mechanism disposed in proximity to the curved guide and associated therewith in such a way as to allow it to perform a movement, specifically a rotation, about the axis of adjustment "X".
Preferably, the second crimping roller 22 is adjustably mounted on the supporting element 23 in such a way as to allow varying its position relative to the first crimping roller 21.
This technical feature allows moving the second crimping roller 22 towards/away from the first crimping roller 21 in such a way as, for example, to allow inserting the web 100, facilitate maintenance and repairs on the crimping station 20 or allow adapting the distance between the crimping rollers 21 and 22 as a function of the height or other features of the web 100 to be crimped.
More specifically, the second crimping roller 22 is mounted on the supporting element 23 by means of an eccentric, rotatable roller bracket 22a.
The roller bracket 22a is configured to rotate about a respective axis of rotation "Y" parallel to the axis of adjustment "X" and the second crimping roller 22 is mounted on the roller bracket 22a rotatably about a respective axis of rotation "Z" parallel and eccentric relative to the axis of rotation "Y" of the roller bracket 22a.
That way, the rotation of the roller bracket 22a about its axis of rotation "Y" causes displacement of the axis of rotation "Z" of the second crimping roller 22 and hence, displacement of the crimping rollers 21, 22 relative to each other.
The roller bracket 22a is associated with an actuator configured to rotate the roller bracket 22a by a fine adjustment movement about the respective axis of rotation "Y".
In other words, the supporting element 23 comprises an actuator which allows rotating the roller bracket 22a in such a way as to cause the second crimping roller 22 mounted thereon to rotate eccentrically, thereby moving it towards/away from the first crimping roller 21.
In order to optimize adjustment of the rotational movement of the roller bracket 22a, the supporting element 23 comprises a limit stop device which defines a limit to the rotational movement of the roller bracket.
The limit stop device may be embodied, for example, by an adjustment screw or a rotary lead nut and screw coupling, so as to allow the angular stroke of the roller bracket 22a to be adjusted very precisely.
Preferably upstream of the crimping rollers 21, 22 relative to the feed direction "A" of the web 100, the crimping station 20 also comprises a guide roller 24 mounted on the supporting element 23 eccentrically relative to the axis of adjustment "X".
More specifically, the guide roller 24 is associated with the supporting element 23 in such a way as to intercept and divert the stretch of the web 100 between the exit of the infeed station 10, specifically from the diverting roller 13, and the crimping rollers 21, 22 when the supporting element 23 is in a first position interval, and so as not to intercept the web 100 when the supporting element 23 is in a second position interval, different from the first interval, thus moving to a non-operating position.
In particular, in the preferred embodiment where the supporting element 23 is a plate rotatable about the axis of adjustment "X", the first position interval is a first interval of angular positions, while the second position interval is a second interval of angular positions.
In other words, the supporting element 23 is configured to rotate between a plurality of possible positions where the guide roller 24 intercepts or does not intercept the web 100.
In use, therefore, as it passes from the feed station 10 to the crimping station 20 and before it engages the crimping rollers 21, 22, the web may or may not intercept the guide roller 24.
When the web 100 engages the guide roller 24, the latter provides a reference point which determines the point of engagement of the web 100 with the crimping rollers 21, 22 independently of the diverting roller 13, if any, of the feed station 10, and thus allowing stably fixing the geometry of the path followed by the web 100 entering the crimping station 20 and at the same time keeping the possibility of modifying the path at the exit by moving the supporting element 23.
Advantageously, the guide roller 24 is selectively engageable in such a way as to allow fixing or not fixing the geometry of the path followed by the web 100 entering the crimping station 20 depending on whether or not it is necessary to modulate only the path of the web 100 at the exit of the crimping station 20.
Preferably, the guide roller 24 is rotationally at a fixed position on the supporting element 23.
The crimping unit 1 also comprises a gathering station 30 configured to receive the web 100 and progressively gather it in order to give the web a substantially cylindrical shape.
More specifically, along the feed direction "A" of the web 100, the gathering station 30 comprises a pre-shaping member 31 whose cross-sectional shape transverse to the feed direction "A" is curved and shaped to give the web 100 a shape substantially like that of a U.
In other words, the shape of the pre-shaping member 31 is such as to allow the web 100 from the crimping station 20 to be deformed by simultaneously closing the web on itself to obtain an at least partly cylindrical shape of the web 100, preferably according to the above mentioned substantially U shaped form, and folding the web on at least some of the longitudinal fold lines.
The gathering station 30 also comprises a shaping device 32 configured to receive the pre-shaped web 100 from the pre-shaping member 31.
The shaping device has a shaping duct 32a, described in more detail below, whose function is to reduce the web 100 by forcing it to pass through a tubular duct in such a way as to give the web 100 the substantially cylindrical shape.
More specifically, the outside surface 31a has a general shape which, in transverse cross-section, is at least partly annular or tubular, to give the web 100 a substantially cylindrical shape, and, along it, the outside surface 31a is provided with a succession of protrusions and recesses adapted to engage the web 100 at respective longitudinal easy folding lines in such a way as to pre-fold the web 100 simultaneously along the longitudinal easy folding lines.
Preferably, the protrusions and recesses are distributed along the entire outside surface 31a of the pre-shaping member 31.
Still more preferably, the protrusions and recesses are distributed non-uniformly along the outside surface 31a of the pre-shaping member 31.
More specifically, the spacing between adjacent protrusions for engaging a portion of the edge of the web 100 is greater than the spacing between adjacent protrusions intended to engage a central portion of the web 100.
This structure allows obtaining a particularly functional distribution of the pressure on the web 100, transferring the latter in optimum manner to the shaping device 32 in such a way as to improve the structural quality of the continuous stream resulting from the step of gathering the web 100.
The outside surface 31a of the pre-shaping member 31 extends along an open line joined by a supporting portion 31b configured to keep the pre-shaping member 31 suspended at a predetermined position.
In other words, the pre-shaping member 31 comprises a supporting portion 31b which supports and connects it to the body of the crimping unit 1 in such way that it can, in use, remain in the correct position to engage the web 100.
The crimping unit also comprises adjustment means 31c, associated with the supporting portion 31b, for adjusting the position and/or orientation of the pre-shaping member 31.
The presence of the adjustment means 31c allows moving the pre-shaping member 31 to dynamically modify its position and/or orientation, in particular relative to the web 100.
This movement is accomplished preferably by a translation in a direction perpendicular to the feed direction of the web 100 around the pre-shaping member 32 and may adopt a vertical orientation when the web 100 passes horizontally over the pre-shaping member 32.
This movement may also be accomplished by a rotation about an axis of rotation "K" transverse to the feed direction of the web 100 and preferably horizontal. This rotation can therefore be added to the aforementioned translational movement and is preferably controllable independently thereof.
That way, it is possible to vary both the force applied by the pre-shaping member 31 on the web 100 and the extent of the outside surface of it 31a which comes into contact with the web.
In a preferred embodiment shown in the accompanying drawings, the pre-shaping device 31 is configured to be positioned above the web 100 and to tension it by applying a downwardly directed force.
In other words, the outside surface 31a of the pre-shaping member 31 has an upward facing concavity and the adjustment means 31c are configured to lower the pre-shaping member 31 to engage the web 100 by pushing it downwards or to lift the pre-shaping member 31 to reduce the force it applies on the web 100 until it is disengaged from the web.
It is stressed, therefore, that the adjustment means 31c might also be configured to perform only the rotational movement about the axis "K" without necessarily being structured to perform the translational movement, and vice versa.
The gathering station 30 also comprises a shaping duct 32a and an inserting device 33 configured to insert an additional component "C" into the stream formed by the gathered web 100.
More specifically, the inserting device 33 comprises an inserting duct 34 for inserting the additional component "C" placed inside the shaping duct 32a, preferably coaxially therewith.
That way, the additional component "C" is positioned centrally in the rod formed by gathering the web 100.
Advantageously, the shaping duct 32a is convergent in shape along the feed direction of the additional component "C" which substantially coincides with the feed direction "A" of the web 100, at least in the stretch of path through the gathering station 30.
In a preferred embodiment, the shaping duct 32a has a frustoconical profile.
More specifically, as illustrated in Figures 3 and 3a, the shaping duct 32a comprises a tubular element 37 with a longitudinal axis "L" and has an outside wall 38 and an inside wall 39.
The tubular element 37 has an inlet opening 40, where the pre-shaped web 100 enters, and an outlet opening 41 through which the web 100 exits with a substantially cylindrical shape.
The tubular element 37 comprises a plurality of sections disposed in sequence along its longitudinal axis L.
More precisely, the sections are disposed one after the other and are connected to each other. The sections of the tubular element 37 are connected to one another and their respective transverse tubular inside dimensions vary along the longitudinal axis "L".
In other words, the transverse dimensions of the respective inside walls of the aforesaid sections can increase, decrease or remain constant along their extension along the longitudinal axis L.
Taking as references the longitudinal axis "L" and the feed direction of the web 100, indicated by the arrow F, which, in Figures 3 and 3a, is directed from right to left, the tubular element comprises an inlet section 42, a first intermediate section 43, a second intermediate section 44 and an outlet section 45. The different sections are disposed one after the other and are connected to each other.
More specifically, at the inlet section 42, the inside wall 39 has a portion 39a which has a frustoconical shape, convergent towards the longitudinal axis L. At the first intermediate section 43, the inside wall 39 has a portion 39b which is frustoconical in shape, divergent towards the feed direction F and which, at its outlet end, connects with the second intermediate section 44 which has an inside wall portion 39c that is substantially ring-shaped, with a constant diameter along its entire length.
Lastly, the inside wall portion 39d of the outlet section 45 is frustoconical in shape, convergent towards the outlet opening 41.
It should be noted that during the shaping process, specifically during the passage of the web 100 through the tubular element 37 of the shaping duct 32a, strong friction is created between the inside wall 39 and the fibres of the web 100 sliding against it.
As a result, both the tubular element 37 and the web 100, especially the outermost fibres thereof, are heated.
To prevent heating resulting in poor quality end products, the gathering station, specifically the shaping duct 32a, comprises pneumatic conveying means associated with the shaping duct 32a to convey and cool the web of material 100 as it traverses the shaping duct 32a through flows of a pressurized fluid which act on the shaping duct 32a in between the web 100 and the inside surface of the shaping duct 32a itself.
The pneumatic, conveying and cooling means are defined by flows of a pressurized fluid acting on the shaping duct 32a.
The pneumatic, conveying and cooling means constitute lubricating means distributed along the inside wall 39 of the tubular element 37 and capable of flowing between the two surfaces which come into contact with each other as the web 100 moves forward through the shaping duct 32a.
More specifically, the surface of the web 100 slides against the inside wall of the tubular element 37.
More specifically, the pneumatic, conveying and cooling means comprise a plurality of ducts 46 extending from an annular chamber, converging axially towards the longitudinal axis "L" of the tubular element 37 and leading into respective openings 46a made in the tubular element 37
Preferably, the ducts 46 of the plurality of ducts 46 are angularly distributed round the longitudinal axis L.
In the embodiment illustrated in Figures 3 and 3a, the openings 46a are made at the inlet end of the first intermediate section.
The openings 46a are connected at their inlet ends to a source of pressurized fluid and lead into the tubular element 37.
The pressurized fluid, usually air, reaches the openings 46a by way of a chamber defined by a tubular liner 48. More specifically, the liner is not provided at the outlet end of the element 37.
The outlets of the openings 46a preferably have the shape of an isosceles triangle with the vertex directed towards the aforementioned outlet opening 41. They are angularly distributed over the entire surface of revolution of the inside wall 39 at the inlet end of the first intermediate section.
The pressurized fluid, or rather, the multiple flows of fluid, emitted by the openings 46a, is distributed in a substantially uniform manner over the entire inside surface of the wall 39, following a feed direction towards the outlet opening 41 of the tubular element 37.
The flows of fluid form an uninterrupted layer of pressurized fluid which is distributed over the entire surface of the inside wall 39 and which creates a layer of pneumatic "lubricant" between the web of material 100 and the wall 39. The web of material 100 moving towards the outlet opening 41 tends to not stick to the inside wall 39 and is thus prevented from rubbing against the latter.
The pressurized fluid, besides creating the layer of "lubricant", also constitutes a coolant which cools the tubular element 37.
In effect, the flow of cold fluid along the chamber defined by the tubular liner 48 also has the effect of cooling the tubular element 37.
Obviously, cooling the tubular element 37 means that its inside wall 39 is cooled which in turn cools the web 100 that is being progressively reduced.
Returning now to the additional component "C", this is preferably a flavouring component which allows giving the web 100 a specific aroma to modify the flavour of the smoke produced by the end product made using the web 100. More specifically, the flavouring component may comprise a thread made of or impregnated with a flavouring material. To ensure the flavouring thread is correctly transferred into the web 100, the inserting device 33 comprises tensioning members 33a adapted to keep the flavouring thread under tension.
The inserting device may further comprises a roll holder 35 configured to support a plurality of rolls of additional component "C" and to adopt variable positions and/or orientations in such a way as to change the position of the rolls.
The presence of the roll holder 35 optimizes the production process of the rod from the web 100 comprising the additional component "C" because it allows automating the switch from one roll to another in such a way as to allow replacing depleted rolls with new rolls without interrupting the production process of the crimping unit 1.
In other words, this ensures that there is at least one roll of additional material "C" present at all times for use in the production of the end product. More specifically, the roll holder 35 comprises a plurality of supports 36 associable with respective rolls of additional material "C" and rotatable to move the respective rolls towards or away from the forming duct 32a.
The roll holder 35 is thus configured to move a single support 36 containing a roll of additional material "C" to the forming duct 32a and, when the roll is nearly depleted, to move it away from the forming duct 32a and to automatically replace it with a new roll on another support 36.
Advantageously, the openings 46a and the flows of pressurized fluid constitute an effective means of cooling the shaping duct and effective lubricating means interposed between the web and the inside wall of the tubular element 37. Also advantageously, the inserting device provides a particularly efficient and functional solution for precisely and effectively inserting an additional component "C" inside the rod obtainable from the web 100.
In the light of the above, this invention achieves the preset aims and overcomes the abovementioned disadvantages of the prior art by providing a crimping unit which allows optimizing the process of crimping the web 100 and making a continuous rod from that web of material for the tobacco industry.

Claims

A crimping unit for crimping a web of material (100) used to make tobacco industry products, comprising:
- a crimping station (20) having a first crimping roller (21) and a second crimping roller (22) operatively coupled to make a plurality of longitudinal easy folding lines on the web of material (100) in transit between the crimping rollers (21, 22);

- a gathering station (30), located downstream of the crimping station (20) and comprising a shaping duct (32a) configured to receive the web of material (100) and progressively gather it in order to give the web of material (100) a substantially cylindrical shape.
the crimping unit being characterized in that it comprises pneumatic, conveying and cooling means associated with the shaping duct (32a) to convey and cool the web of material (100) as it traverses the shaping duct (32a) through flows of a pressurized fluid which act on the shaping duct (32a) in between the web (100) and the inside surface of the shaping duct (32a) itself.
The crimping unit according to claim 1, wherein the pneumatic, conveying and cooling means are defined by flows of a pressurized fluid acting on the shaping duct (32a) and capable of flowing between the two surfaces which come into contact with each other as the web (100) moves forward through the shaping duct (32a) itself.
The crimping unit according to claim 1 or 2, wherein the pneumatic, conveying and cooling means comprise a plurality of ducts (46) extending from an annular chamber, converging axially towards a longitudinal axis (L) of the tubular element (37) and leading into respective openings (46a) made in the tubular element (37).
The crimping unit according to claim 3, wherein the ducts (46) of the plurality of ducts (46) are angularly distributed round the longitudinal axis (L).
The crimping unit according to one or more of the preceding claims, wherein the tubular element (37) comprises a chamber defined by a tubular liner (48) at least partly surrounding the outer wall (39) of the tubular element (37), the pneumatic, conveying and cooling means comprising a pressurized fluid capable of passing through the chamber and cooling the tubular element (37) itself.
The crimping unit according to one or more of the preceding claims, wherein the gathering station (30) comprises an inserting device (33) configured to insert an additional component (C) into the stream formed by the gathered web (100).
The crimping unit according to one or more of the preceding claims, wherein the inserting device (33) comprises an inserting duct (34) for inserting the additional component (C) placed inside the shaping duct (32a), preferably coaxially therewith.
The unit according to claim 6, wherein the shaping duct (32a) is convergent in shape along the feed direction of the additional component (C), the shaping duct (32a) preferably having a frustoconical profile.
The unit according to one or more of claims 6 to 8, wherein the additional component (C) is a flavouring component.
The unit according to claim 9, wherein the flavouring component comprises a thread made of or impregnated with a flavouring material.
The unit according to claim 10, wherein the inserting device (33) comprises tensioning members (33a) adapted to keep the flavouring thread under tension.
The unit according to one or more of claims 6 to 11, wherein the inserting device (33) comprises a roll holder (35) configured to support a plurality of rolls of additional component (C) and to adopt a variable positions and/or orientations in such a way as to change the position of the rolls.
The unit according to claim 12, wherein the roll holder (35) comprises a plurality of supports (36) associable with respective rolls and rotatable to move the respective rolls towards or away from the transfer duct (34).