Apparatus for applying a liquid substance to at least one belt in a machine for making tobacco products

Abstract

 Described is an apparatus (12) for applying a liquid substance to at least one belt (1) in a machine (7) for making tobacco products (5), comprising feed means (11') designed to feed the belt (1) longitudinally along a predetermined path, and a drum (13) for applying coatings (4) of liquid substance on a surface of the belt (1); the applicator drum (13) is rotatable about its own axis (A), has a substantially cylindrical peripheral wall (19) running partly alongside the belt (1) which advances resting against the peripheral wall (19), and is provided on the peripheral wall (19) with a plurality of openings (20) which place in communication the inside of the applicator drum (13) with the portion of belt (1) running alongside the peripheral wall (19); and inside the applicator drum (13) there is at least one spraying unit (23) designed to direct nebulised liquid substance towards the openings (20) adjacent to the belt (1).

Description

[0001] This invention relates to an apparatus for applying a liquid substance to at least one belt in a machine for making tobacco products.

[0002] More specifically, the invention relates to an apparatus which can be used for applying to at least one belt of paper for cigarettes coatings of liquid substance, comprising for example an aromatising substance or a substance with a low propensity to combustion.

[0003] Hereinafter in this description reference is made, by way of an example and for simplicity, to the application of coatings of substance with a low propensity to combustion to paper for cigarettes without thereby restricting the scope of the invention.

[0004] In the prior art additives which are able to control combustion characteristics are added to a belt of paper for cigarettes and in particular to relative predetermined zones. This operation is most frequently performed during production of the belt, but is sometimes performed on board the machines for the production of cigarettes.

[0005] The additives are usually applied to the machine in such a way that, in the continuous rod of tobacco which will be wrapped in the belt, the zones for controlling the combustion have an annular shape and are spaced from each other along the longitudinal direction of extension of the belt.

[0006] The aim of the additives described above is that the cigarettes in which the tobacco has been wrapped by the paper with additives behave in a perfectly normal manner when the smoker inhales at normal intervals, but that they have a propensity to reduced combustion when the lit cigarette has not been inhaled for a certain time. Cigarettes made using paper treated in the above-mentioned manner have the advantage of going out after a short time when the smoker stops smoking them, and they are unlikely to start fires if they are left in contact with combustible materials.

[0007] Many techniques have been proposed and used for applying the above-mentioned additives to belts of paper for cigarettes, based in particular on printing methods, or coating the belt by "spreading " using bladed elements, or the depositing of additives using applicator rollers or by screen printing.

[0008] The apparatuses operating according to these concepts have shown a considerable propensity to a getting dirty, over time, with the additive substances manipulated by them, and the soiling of the elements for applying the additives results in a poor quality of shape and irregularities in the quantities of additive coatings applied to the belts of paper for cigarettes.

[0009] Moreover, the use of this apparatus on board machines for the production of cigarettes has been found to be somewhat problematic due to the extremely high operating speed of the machines, which speeds up the occurrence of the cleaning problems and makes it necessary to frequently stop the machine to remove the soiling.

[0010] The aim of this invention is to provide an apparatus for applying a liquid substance to at least one belt in a machine for making tobacco products which overcomes the above-mentioned drawbacks with reference to the prior art.

[0011] The invention accordingly provides an apparatus for applying a liquid substance to at least one belt in a machine for making tobacco products as described in the appended claims.

[0012] This invention is described below with reference to the accompanying drawings, which illustrate a non-limiting embodiment, and in which:

• Figure 1 shows a portion of paper belt for cigarettes manipulated by an apparatus made according to this invention;
• Figure 2 is a perspective view of a cigarette made using a portion of the belt of Figure 1;
• Figure 3 is a schematic front view of a portion of a machine for the production of cigarettes incorporating the apparatus according to this invention;
• Figure 4 is a schematic cross section of the apparatus according to the invention; and
• Figures 5 and 6 are respective schematic cross sections of a portion of the apparatus according to this invention.

[0013] With reference to Figure 1 the numeral 1 denotes a paper belt for cigarettes. The belt 1 has been shown, by way of an example, in the form commonly used in double line machines for the production of cigarettes, and therefore has twice the width of that which can be used in single line machines as it is designed to be subdivided longitudinally into two halves along a longitudinal centre line 2. However, this invention can also be validly used for manipulating single belts which can be used in single line machines for the production of cigarettes, or for the simultaneous manipulating of two or more different belts.

[0014] The belt 1, after having been manipulated by the apparatus according to this invention, has its two halves, positioned on opposite sides of the longitudinal centre line 2, provided with respective rows 3 of rectangular (for example) coatings 4 of additive. The deposits 4 comprise a substance with a low propensity to combustion, are preferably and by way of an example arranged perpendicular to the line 2, have been applied on the belt 1 in a liquid form and have then been immediately dried. Each coating 4 has a length and a position such as to not touch a side edge zone adjacent to it and the central zone of the belt 1.

[0015] As shown in Figure 2, the cigarettes 5 obtained wrapping tobacco inside the belt 1 have a plurality of coatings 4 distanced from each other and distributed along the cigarettes 5 in such a way as to not be present on their end portions opposite the filter 6 (when present). The coatings 4, in the cigarettes 5, have adopted an annular shape following the wrapping of the belt 1 in a cylindrical shape about the tobacco.

[0016] Figure 3 shows a schematic and partial view of a machine 7 for the production of cigarettes 5.

[0017] The machine 7 comprises a section 8 for feeding a continuous flow 9 of tobacco, designed to continuously pour the continuous flow 9 on a horizontal section of a belt 1 of paper (in a machine with one production line) or on two horizontal sections positioned side by side of respective belts made by cutting longitudinally in half the belt 1 in a machine with two production lines. Each belt 1 is wound with a tube shape about the tobacco, to form a continuous cigarette rod using a forming beam, labelled 11 in its entirety. Upstream of the forming beam 11 there are feed means 11' designed to feed the belt 1 longitudinally along a predetermined path.

[0018] Each belt 1 reaches the forming beam 11 after passing through an apparatus 12, according to this invention, for applying on the belt 1 a liquid substance. The liquid substance can comprise, for example, an aromatising material, or a substance with a low propensity to combustion. The apparatus 12, as shown in Figures 4 to 6, comprises a drum 13 for applying the above-mentioned liquid substance, which revolves continuously, in a clockwise direction in Figures 4 and 6, about a horizontal axis under the action of motor means not illustrated.

[0019] The drum 13 is supported in a rotatable fashion by a vertical wall 14 (Figure 5), using a sleeve 16 coaxial with the drum 13 and integral with the wall 14, and it is rotated by a shaft 17 connected to it and contained coaxially inside the sleeve 16. The drum 13 is closed, by walls 18, at its two axially opposite circular sides, and it is defined, at the relative surface portion of cylindrical shape, by a wall or shell 19 with a substantially circular annular shape coaxial with the shaft 17. The wall 19 has a small thickness, preferably between 0.3 and 5 mm, and is equipped (Figures 4 and 5) with a plurality of openings 20 having exactly the arrangement and shape as the coatings 4 to be applied on the belt 1 according to the above-mentioned Figure 1. More specifically, in the embodiment shown by way of an example the openings 20 are positioned on two annular rows 21 side by side, alongside each other in a direction parallel to the axis A of the shaft 17, with an arrangement equal to that of the coatings 4 shown in Figure 1.

[0020] It should be noted that in that embodiment there are two rows 21 as the drum 13 shown is provided for use in a machine 7 with two lines for the production of cigarettes 5, wherein the two belts for wrapping the tobacco are made, by longitudinal cutting in the middle zone, from a single belt 1 on which two rows 3 of coatings 4 are applied alongside each other. If the drum 13 is designed for use in a machine 7 for the production of cigarettes 5 equipped with a different number of production lines, the number of rows 21 of openings 20 should be kept preferably equal to the number of rows of coatings 4 to be applied, and therefore, for example in the presence of one production line, there would preferably be a singe row 21 of openings 20 (there could, however, be more rows, in the case in which every coating 4 is replaced by a plurality of coatings side by side with each other parallel to the axis A of rotation of the drum 13).

[0021] Inside the drum 13 there is at least one unit 23 for spraying the above-mentioned liquid substance towards the openings 20 of the wall 19. In the embodiments of the apparatus 12 shown in Figures 4 and 6 there are three spraying units 23, angularly equispaced from each other about the shaft 17 and able to spray the liquid substance (preferably) radially relative to the drum 13.

[0022] Each spraying unit 23 comprises two spray guns 24 placed side by side according to a direction parallel to that of the axis A of rotation of the drum 13, having a direction of action substantially radial relative to the drum 13 and supported in a fixed position.

[0023] Each of the spray guns 24 is equipped with at least one dispensing nozzle 25, located alongside the inner surface of the wall 19 and positioned in such a way as to run alongside in succession the openings 20 of a row 21 as the drum 13 rotates.

[0024] The two spray guns 24 of each spraying unit 23 could be replaced by a single spray gun (not illustrated) equipped with two dispensing nozzles located in the same position as the dispensing nozzles 25.

[0025] The spray guns 24 are connected, by conduits 26, to a unit for dispensing the above-mentioned liquid substance represented as a block 27.

[0026] Inside the drum 13, downstream of the spraying unit 23 with reference to the direction of rotation of the drum 13, there are scraping means comprising at least one scraping device 28 (two in the example shown) designed to remove from the inner surface of the wall 19 the coatings of liquid substance present. Each scraping device 28 comprises a blade 29 positioned in contact with the wall 19, supported by a supporting element 30 which, together with the blade 19 and the wall 19, defines a substantially closed chamber 31 communicating, by a conduit 32, with a suction source schematically represented as a block 32'. Preferably, at least one scraping device 28 is positioned between the spraying units 23 and the area in which the belt 1 detaches from the drum 13, and at least one further scraping device 28 is positioned downstream of the area in which the belt 1 detaches from the drum 13 with reference to the direction of rotation of the drum 13.

[0027] In use, the liquid substance removed from the blades 29 of the scraping devices 28 is extracted from the drum 13 by the suction source 32'.

[0028] As shown in particular in Figure 4, the above-mentioned belt 1, when passing through the apparatus 12 for applying the above-mentioned liquid substance, runs alongside the cylindrical wall 19 of the drum 13 along an arc having an amplitude substantially equal to 180°, as it comes into contact with the drum 13 moving forward horizontally coming from the right, and loses contact with the upper zone of the drum 13 to run alongside, along an arch having an amplitude also substantially equal to 180°, a further roller 33 positioned above the drum 13. The roller 33 is rotatable about an axis B parallel to the axis A of rotation of the drum 13, with a direction of rotation opposite to that of the drum 13, and is supported by the above-mentioned wall 14 close to the drum 13.

[0029] Heating means 34 designed to heat the belt 1 coming from the drum 13 are associated with the peripheral cylindrical surface of the roller 33. Further heating means 34', of per se known type, can be positioned along the trajectory travelled by the belt 1 downstream of the drum 13, in addition or as an alternative to the heating means 34, to heat the belt 1 coming from the drum 13 and favour a fast evaporation of the solvent (usually water) present in the liquid substance applied to the belt 1.

[0030] A scraping device 35 runs alongside the outer surface 19 of the drum 13 immediately downstream (with reference to the direction of rotation of the drum 13) of the zone of substantial tangency between the drum 13 and the roller 33. The scraping device 35 comprises a box-shaped body 36, having a relative inner chamber 37 positioned adjacent to, and substantially airtight with, the outer surface of the wall 19 and housing inside a blade 38 positioned in contact with the wall 19. The chamber 37 communicates, by a conduit 39, with a suction source schematically represented as a block 40. In use, the liquid substance removed from the blade 38 of the scraping device 35 is extracted from the chamber 37 by the suction source 40.

[0031] If deemed necessary, the inner cavity 13' of the drum 13 can be positioned in communication with a suction source schematically represented as a block 41 for constantly removing the vapours and the droplets of liquid substance present inside the inner cavity 13'.

[0032] As shown in Figure 6, the portion of the above-mentioned belt 1 which, when passing through the apparatus 12 for applying the above-mentioned liquid substance, adheres to the cylindrical wall 19 of the drum 13 is run alongside by three suction devices 41' angularly equispaced from each other in pairs about the shaft 17. Each suction device 41' comprises a chamber 42 positioned side by side in a sealed manner with a portion of belt 1, communicating with a suction source 43, and is able to exert suction on the surface of the belt 1 opposite to that on which the above-mentioned liquid substance is applied, for facilitating the entrance of the substance into the inner fibres of the belt 1 due to the negative pressure to which the substance is subjected through the porosity of the paper of which the belt 1 is comprised.

[0033] If desired, the suction devices 41 described above could be absent or there may be a different number from that mentioned above.

[0034] In use, during rotation of the drum 13, the spray guns 24 are actuated, preferably intermittently and in synchrony with the passage of the openings 20 of the wall 19 in their radius of action, for directing towards the belt 1, through the openings 20 adjacent to the belt 1, coatings 4 of predetermined shape (that of the openings 20) comprising the above-mentioned liquid substance.

[0035] The action of the above-mentioned heating means 34 and 34' favours a fast evaporation of the solvent present in the liquid substance applied to the belt 1.

[0036] It should be noted that the roller 33 also has the purpose of modifying the alignment of the belt 1 which has just left the drum 13, in such a way that the coatings 4 of liquid substance, at the forming beam 11, are facing upwards in such a way that, in the finished cigarettes 5, they are located inside the cigarettes 5.

Claims

1. An apparatus for applying a liquid substance to at least one belt in a machine for making tobacco products, characterised in that it comprises feed means (11') feeding the belt (1) longitudinally along a predetermined path, and a drum (13) for applying coatings (4) of liquid substance on a surface of the belt (1); the applicator drum (13) being rotatable about its own axis (A), having a substantially cylindrical peripheral wall (19) running partly alongside the belt (1) which advances, in use, resting against the peripheral wall (19), and being provided on the peripheral wall (19) with a plurality of openings (20) placing in communication the inside of the applicator drum (13) with the portion of belt (1) running alongside the peripheral wall (19); and there being inside the applicator drum (13) at least one spraying unit (23) designed to direct, in use, nebulised liquid substance towards the openings (20) adjacent to the belt (1).

2. The apparatus according to claim 1, characterised in that each spraying unit (23) comprises at least one spray gun (24) to direct the coatings (4) of liquid substance towards the belt (1) through the openings (20) of the peripheral wall (19).

3. The apparatus according to claim 2, characterised in that each spray gun (24) is actuated intermittently to direct the coatings (4) of liquid substance towards the belt (1) through the openings (20) of the peripheral wall (19).

4. The apparatus according to claim 3, characterised in that each spray gun (24) is actuated in synchrony with the passage of the openings (20) of the peripheral wall (19) in its radius of action.

5. The apparatus according to any one of claims 1 to 4, characterised in that it comprises heating means (34, 34') for heating the belt (1) coming from the applicator drum (13) so as to favour a fast evaporation of the solvent present in the liquid substance applied to the belt (1).

6. The apparatus according to claim 5, characterised in that the heating means (34) are associated with a roller (33) counter rotating with respect to the applicator drum (13) and run alongside by the belt (1) coming from the applicator drum (13).

7. The apparatus according to claim 6, characterised in that it comprises further heating means (34') positioned, with reference to the direction of feed of the belt (1), downstream of the roller (33) counter rotating with respect to the applicator drum (13).

8. The apparatus according to any one of claims 1 to 7, characterised in that it comprises first scraping means (35) associated with the outer surface of the peripheral wall (19) of the applicator drum (13) for removing any liquid substance present on that surface.

9. The apparatus according to claim 8, characterised in that it comprises first suction means (40) for removing from the first scraping means (35) the liquid substance removed from the peripheral wall (19) of the applicator drum (13).

10. The apparatus according to any one of claims 1 to 9, characterised in that it comprises second scraping means (28) associated with the inner surface of the peripheral wall (19) of the applicator drum (13) for removing any liquid substance present on that surface.

11. The apparatus according to claim 10, characterised in that it comprises second suction means (32') for removing from the second scraping means (28) the liquid substance removed from the peripheral wall (19) of the applicator drum (13).

12. The apparatus according to claim 10 or 11, characterised in that the second scraping means comprise at least one scraping device (28) positioned between the spraying units (23) and the area in which the belt (1) detaches from the applicator drum (13), and at least one further scraping device (28) positioned downstream of the area in which the belt (1) detaches from the applicator drum (13) with reference to the direction of rotation of the applicator drum (13).

13. The apparatus according to any one of claims 1 to 12, characterised in that it comprises further suction means (41) for removing from the inner cavity (13') of the applicator drum (13) the vapours and the droplets of liquid substance present inside the inner cavity (13').

14. The apparatus according to any one of claims 1 to 13, characterised in that it comprises at least one suction device (41'), comprising a chamber (42) positioned side by side in a sealed manner with a portion of the belt (1) running alongside the peripheral wall (19) of the applicator drum (13).

Drawing