EP3509445B1

EP3509445B1 - A method and apparatus for producing a filter rod for smoking articles

Info

Publication number: EP3509445B1
Application number: EP17772116.4A
Authority: EP
Inventors: Antonella Giannini; Alberto Monzoni
Original assignee: Montrade SpA
Current assignee: Montrade SpA
Priority date: 2016-09-08
Filing date: 2017-09-06
Publication date: 2021-10-06
Anticipated expiration: 2037-09-06
Also published as: US20190246689A1; EP3509445A1; CN109936985A; EA201990545A1; IT201600090857A1; WO2018047075A1

Description

Field of the invention

The present invention relates to methods and apparatus for continuous production of filter rods for smoking articles, of the type in which a belt conveyor system is provided for advancing a rod of filter material along a forming path, and in which said belt conveyor system comprises at least one endless belt, having an upper conveying run for conveying the filter rod.

Prior art

Since long, apparatus of the aforementioned type have been known, which are for producing filter rods consisting of a filter material (typically cellulose acetate) and having no outer wrapping sheet. These filter rods are to be divided into sections of predetermined lengths to form non-wrapped cellulose acetate or "NWA" filter segments.
A machine of the aforementioned type is described and illustrated in European Patent EP 2 636 321 B1 of the same Applicant. In apparatus of this type, the filter rod is advanced along the forming path by means of a belt conveyor system including a single endless belt, the upper run of which is in direct contact with the filter rod.
The use of a transport system has also been proposed in the past ( US 6,932,752 B2 ) that includes two endless conveyor belts, arranged one downstream of the other, in an apparatus for producing multi-component filter rods, in which a succession of filter segments is wrapped within an outer wrapping sheet. In this known solution, the provision of two conveyor belts has been proposed simply to avoid the elongation and side movement to which a single conveyor belt is subjected to, and to enable control of the tension state of the wrapping sheet that is interposed between the transport belts and the filter segments.
A solution with more conveyor belts is also known from documents EP 1 872 673 A1 and US 4 291 711 .

Object of the invention

Starting from the above-mentioned known solutions, the Applicant has been faced with the problem of producing an apparatus and a method for producing filter rods that provides an improved control on the quality and characteristics of the finally obtained product.

Summary of the invention

In view of achieving the aforesaid object, the invention relates to a method of the type indicated at the beginning of this description and according to Claim 1. Further examples include a drying operation or providing an additive material, such as a dye or flavoring material, for example in the form of microcapsules, or an outer coating material.
"Forming path" in this description, and in the following claims, means the path that starts from the inlet of the filter rod forming channel and terminates with a cutting device that is conventionally used along the production line to divide the filter rod into pieces of pre-determined lengths.
In a preferred embodiment, the material constituting the filter rod (M) is without an outer wrapping sheet. In the case of this application, a further aspect of the invention, is directed to a method of the type indicated at the beginning of this description, in which a rod of filter material is advanced along a forming path, characterized in that the aforesaid belt conveyor system comprises at least two separate conveyor belts, having respective upper conveying runs arranged one downstream of the other along said forming path, and in that that the movement speeds of said conveyor belts are controlled according to a predetermined ratio, said predetermined ratio being selected so as to obtain a controlled axial stretching effect or a controlled axial compacting effect on the material of the filter rod, as a result of the transition from one conveyor belt to theother, so as to influence the characteristics of the obtained filter rod in the required manner.
The Applicant has, for the first time, found that applying a double-belt conveyor system to a method for producing filter rods with no outer wrapping sheet allows control of the configuration and quality of the final product to be obtained with extremely simple and effective means.
Control of the ratio between the movement speeds of the two conveyor belts is exploited to modify the configuration and/or structure of the filter rod. If the downstream belt is driven at a greater speed than the upstream belt, elongation of the product is obtained. If the downstream belt is driven at a lower speed than the speed of the upstream belt, compaction of the product is obtained.
As already mentioned above, in the prior art, the provision of two conveyor belts was proposed solely with reference to multi-component filter rods including a succession of filter segments wrapped in a wrapping sheet. In these known solutions, the control of the speed of the conveyor belts had, at most, only the benefit of controlling the tension of the tape of wrapping material of the filter segments. In the case of the present invention, instead, controlling the speeds of the conveyor belts allows, for the first time, the characteristics of the final product to be influenced as desired, producing the required axial stretching or required axial compacting on the filter rod that advances along the forming path.
In a further embodiment, in the area between the upper runs of said at least two conveyor belts, an operation is performed that modifies the configuration and/or the structure of the filter rod, such as shaping of the filter rod cross-section and/or embossing and/or marking of the filter rod surface and/or feeding of filter material to form an outer layer of the filter rod.
More generally, the transition area from one conveyor belt to the other is used to carry out any further operation on the filter rod material without having any hindrance due to the presence of the conveyor belt.
In a further embodiment, the product quality is influenced by controlling the ratio between the speeds of the two conveyor belts and by operating on the rod material in the area interposed between the upper runs of the two conveyor belts.
In the case in which the intermediate station between the two conveyor belts involves feeding a layer of material, it is also possible to envisage that the rod fed along the upstream conveyor belt is provided with a wrapping sheet, and that, conversely, the downstream belt is not associated with any wrapping sheet, so that the final rod obtained is, however, without any outer wrapping sheet.
The method according to the invention can also be used, in particular, for producing a filter rod with a coaxial configuration structure, comprising an outer layer of filter material, without an outer wrapping sheet, and an inner body in the form of a paper or cardboard tube, or an inner body of filter material.
The present invention also relates to the apparatus used to implement the method of the invention, according to that indicated in attached claim 5.
Naturally, although the embodiments described herein refer to two conveyor belts, there is nothing to exclude that the apparatus and the method according to the invention can provide more than two conveyor belts, according to the needs of each specific application. In addition, along the upper run of each conveyor belt, all necessary operations to which the filter rod material is to be subjected can be carried out, such as vapor insufflation operations, in order to activate a hardening agent (typically triacetin) previously added to the material constituting the filter rod, and/or drying operations, to cause subsequent hardening of the filter rod, or any subsequent operation, such as the addition of flavoring material.

Description of preferred embodiments of the invention

Further characteristics and advantages of the invention will become apparent from the description that follows with reference to the attached drawings, provided purely by way of non-limiting example, wherein:

Figure 1 is a diagrammatic side view of an apparatus according to the prior art known from document US 6,932,752 B2 ,
Figure 2 is a diagrammatic perspective view of a first embodiment of the apparatus according to the invention,
Figure 3 is a diagrammatic perspective view of a second embodiment of the apparatus according to the invention,
Figure 4 shows an example of a filter rod with a coaxial configuration, which can also be obtained by the method and the apparatus according to the invention, and
Figure 5 is a diagram of the two successive operating steps provided in an embodiment of the method according to the invention, in order to produce the product of Figure 4.

As indicated above, Figure 1 illustrates a diagrammatic side view of an apparatus according to the prior art known from document US 6,932,752 B2 . This document shows an apparatus usable for producing multi-component filter rods, in which a plurality of filter segments 24 are fed in succession above a tape of wrapping paper 18, which is unwound by a reel 16 and is fed above a belt conveyor system, including a first conveyor belt 56 and a second conveyor belt 58 arranged one downstream of the other. The upper runs of the two endless conveyor belts 56, 58 are engaged by means of guide devices 52, 54, which wrap the upper runs of the belts and the paper sheet 18 fed above them so as to give them a U-shaped cross-section (at the guide device 52) and then a closed circular cross-section (in the second guide device 54). In this known solution, the speed of the downstream belt 58 is expected to be slightly higher than that of the upstream belt 56 in order to ensure the correct tensioning of the paper tape 18 which wraps around the filter segments 24.
As has already been indicated above, the present invention has been originated from finding that the application of a double-belt conveyor system (known only in the field of equipment for producing multi-component filter rods, of the type illustrated in Figure 1) to the production of filter rods with no outer wrapping sheet, opens the doors to conceiving an invention that allows, for the first time, the characteristics and the quality of the final product obtained to be influenced in an extremely simple and effective way.
However, the invention can also be applied to filter rods with which a wrapping sheet is associated, in which case the solution idea described herein is used, for example, to obtain a required shaping of the wrapping sheet (for example, a tubular shape with circular cross-section of a relatively rigid crimped sheet).
A first example of the apparatus according to the invention is shown in Figure 2. This figure essentially refers to an apparatus of the type that was the subject of prior European patent EP 2 636 321 B1 by the same Applicant, the main difference being that, in this case, the belt conveyor system includes, instead of a single endless conveyor belt, two endless conveyor belts 1, 2 arranged one downstream of the other. In particular, the two conveyor belts 1, 2 have their upper runs aligned and arranged one downstream of the other, along the forming path F of a filter rod M. The material constituting the filter rod M is fed to the inlet of the forming channel F by means (not shown) of any known type.
According to a conventional technique (see, for example, EP 2 636 321 B1 ), the material constituting the filter rod M is advanced through successive processing stations, which may include, for example, a station S1 for vapor insufflation, having the function of activating the hardening agent (triacetin) that was previously added to the filter material M, and subsequent stations S2, S3 for stabilizing the filter rod, of any known type.
The details of construction of the stations S1, S2, S3 are not provided here, since, as already indicated, these stations can be made according to any known art, and as they do not fall, taken alone, within the scope of the present invention. Furthermore, eliminating these details from the drawings makes them more readily and easily understandable.
According to the prior art, when crossing each station, the upper tape of each belt meets a guide device that is configured so as to force the belt to deform laterally, in order to assume a U or O cross-section. However, the case is not excluded that this is implemented only for the upstream belt, which forms the filter rod, while the downstream belt can be left undeformed, with a planar configuration.
Each endless belt is engaged on a plurality of idler rollers R and on a driving wheel P, which actuates the movement of the respective conveyor belt by means of direct frictional contact with it. In the example illustrated in Figure 2, the two driving wheels P are controlled in rotation by respective electric motors M1, M2 (shown only diagrammatically in the drawings, and optionally including respective gear reducing units), said electric motors being, in turn, controlled by an electronic control unit E.
It is, however, evident that the driving system for moving the conveyor belts can be completely different from that illustrated in Figure 2 purely by way of example. For example, a single electric drive motor could be provided with transmission devices that connect the single drive motor to the two conveyor belts, and which can be controlled by the electronic control unit.
In the first embodiment of the present invention illustrated herein, the rotation speeds of the motor wheels P are controlled according to a predetermined ratio, which can be different from 1. This predetermined ratio is selected so as to influence the characteristics of the filter rod M in the required manner. In particular, the speed of the downstream belt 2 can be increased or decreased with respect to the speed of the upstream belt 1, in order to obtain a controlled axial stretching or a controlled axial compacting of the material M constituting the filter rod. In fact, since the upper runs of the two conveyor belts 1, 2 are in frictional contact with the material M constituting the filter rod, they are able to influence the axial elongation or compacting of the rod during transition from one belt to the other, through the programmed control of the respective transport speeds.
This result is completely unreachable in known devices of the type shown in Figure 1, where control of the speed of the conveyor belts can, at most, influence the degree of tensioning of the wrapping tape of the filter segments in a multi-component filter rod.
Naturally, the friction between the filter rod material and the conveyor belts depends, in particular, on the area of the contact surface between the rod and each belt, and on the roughness of the contact surfaces. The contact area is more extended in the case in which the belt is forced to wrap partially or completely around the rod when crossing the processing stations S1, S2, S3. The belt surface can be prepared with a texture that increases friction. The skilled technician can then take advantage of these arrangements to achieve the desired result.
Figure 3 shows an embodiment where the transition area from one conveyor belt to the other can be exploited to carry out any further operation on the filter rod material that requires the absence of the obstacle due to the presence of a conveyor belt. In the case illustrated in Figure 3, in the transition area from the conveyor belt 1 to the conveyor belt 2, embossing rollers 3 are provided, which give an embossed configuration to the surface of the filter rod. Of course, the presence of two separate conveyor belts makes it possible to take advantage of the transition area from one belt to the other, in order to carry out any kind of further processing, for example, shaping of the filter rod cross-section, or a marking operation, or adding flavoring material, or adding an outer layer of filter material around the filter rod. The provision of two separate conveyor belts, therefore, also provides the possibility to influence the configuration and structure of the product by arranging product processing stations in the transition area between the upper runs of the conveyor belts.
In the case in which the intermediate station between the two conveyor belts is for feeding a layer of material, it is also possible to envisage that the rod fed along the upstream conveyor belt is provided with a wrapping sheet, as long as the downstream belt is, however, not associated with any wrapping sheet, so that the final rod obtained is, in any case, without any outer wrapping sheet.
The method according to the invention can also be used, in particular, for producing a filter rod with a coaxial configuration structure, comprising an outer layer of filter material, without an outer wrapping sheet, and an inner body in the form of a paper or cardboard tube, or an inner body of filter material.
Figure 4 of the attached drawings shows an example of a filter rod M of this type, with a hollow inner tube T made of paper or cardboard, and an outer layer R1 of filter material, without an outer wrapping sheet.
Figure 5 diagrammatically shows two successive steps of the forming method of the rod M of Figure 4. In a first step, a wrapping tape W of paper or cardboard is carried by a reel RE, and guided and wrapped around a core C to form the tube T. In a second step, produced downstream in the line, filter material is fed around the tube T to produce the outer layer R1, without an outer wrapping sheet. In the illustrated example, the filter material is fed around the tube T by means of two conventional-type feed devices or jets J, which are configured to receive a cord of filter material (illustrated as a cross-section in the drawing) and to feed it with the aid of a flow of compressed air around the tube T. In Figure 5, for simplicity and clarity, neither the forming channel nor the conveyor belts are illustrated.
In an embodiment of the method according to the invention, the operational steps illustrated in Figure 5 are implemented by arranging the two conveyor belts 1 and 2 in association with the two sections indicated with B1 and B2, respectively, in Figure 5. Therefore, in this case, the upstream conveyor belt 1 has its upper run that receives the tape W above it and advances it through the conventional guide device (not shown), which wraps it in order to form the tube T. The station with feed devices J for the filter material is arranged in the area interposed between the upper runs of the two conveyor belts 1 and 2 (similar to the one shown in Figure 3). The upper run of the downstream conveyor belt 2 comes into direct contact with the outer layer R1 of filter material, and advances the filter rod thus formed through the forming channel and towards the cutting station.
The same solution could be adopted by replacing the tube T with an inner body of filter material, fed at the inlet of the forming channel and above the upper run of the conveyor belt arranged further upstream. The inner body of filter material may or may not have a wrapping sheet, but it is understood that this sheet is, however, covered by the outer layer of filter material.
Also included in the present invention are a method and an apparatus which only rely on the provision of one or more product processing stations in the transition area between the upper runs of the conveyor belts, with equal speeds of the two conveyor belts.
The electronic control unit E is programmed in any predetermined mode, depending on the characteristics of the final product to be obtained. The apparatus according to the invention thus enables a modification of the characteristics of the final product obtained with extremely simple, effective and inexpensive means.
Naturally, without prejudice to the principle of the invention, the details of construction and the embodiments may vary widely with respect to those described and illustrated purely by way of example, without departing from the scope of the present invention as defined by the appended claims.

Claims

A method for the continuous production of a filter rod (M) for smoking articles, said method comprising
providing a belt conveyor system (1, 2) for advancing a rod (M) of filter material along a forming path (F), wherein said belt conveyor system comprises at least one endless belt (1) having an upper conveying run for conveying the filter rod (M),

wherein said belt conveyor system comprises at least two separate conveyor belts (1, 2), having respective upper conveying runs arranged one downstream of the other along said forming path (F), and wherein

in the transition area between the upper runs of said at least two separate conveyor belts (1, 2), an operation is carried out that modifies the configuration and/or structure of the filter rod (M), such as shaping of the filter rod (M) cross-section and/or embossing and/or marking of the surface of the filter rod and/or supplying filter material to form an outer layer of the filter rod and/or shaping a wrapping sheet of the filter rod;

characterized in that

the speeds of movement of said conveyor belts (1, 2) are controlled according to a predetermined ratio, said predetermined ratio being selected so as to obtain a controlled axial stretching effect or a controlled axial compacting effect on the material of the filter rod (M) as a result of the transition from one conveyor belt to the other, so as to influence the characteristics of the produced filter rod (M) in the required manner.
A method according to claim 1, characterized in that the material forming the filter rod (M) has no outer wrapping sheet.
A method according to claim 1, wherein a relatively rigid wrapping sheet is associated with said filter rod, for example a crimped sheet, and characterized in that the required shaping is imparted to said wrapping sheet, for example, a circular cross-sectional tube shape in the aforesaid transition area.
A method according to claim 1, for producing a filter rod having a structure with a coaxial configuration, comprising an outer layer of filter material, which has no wrapping sheet, and an inner body in the form of a tube (T) of paper or cardboard, or an inner body of filter material, characterized in that in the transition area between the upper runs of said at least two conveyor belts (1, 2), an outer layer (R1) of filter material is supplied, in that the downstream conveyor belt (2) is in contact with said outer layer of filter material (R1), and in that the upstream conveyor belt (1) feeds the inner body consisting of said tube (T) of paper or cardboard, or of said inner body of filter material.
An apparatus for the continuous production of a filter rod (M) for smoking articles, comprising a belt conveyor system (1, 2) for advancing a rod (M) of filter material along a forming path (F), wherein said belt conveyor system comprises at least one endless belt (1) having an upper conveying run of the filter rod (M),
wherein said belt conveyor system comprises:
- at least two separate conveyor belts (1, 2), having respective upper conveying runs arranged one downstream of the other along said forming path (F), and wherein

- between the upper runs of said at least two conveyor belts (1, 2), a filter rod (M) processing station is interposed for carrying out an operation that changes the configuration and/or the structure of the filter rod (M), such as shaping of the filter rod (M) and/or marking the surface of the filter rod (M) and/or feeding of filter material to form an outer layer of the filter rod (M) and/or shaping an outer wrapping sheet of the filter rod;

characterized in that
- motor means (M1, M2) associated with said conveyor belts (1, 2), to control the movement of each conveyor belt, and

- an electronic control unit (E) for controlling said motor means (M1, M2), and configured in order to implement a predetermined ratio between the speeds of movement of said conveyor belts (1, 2), said predetermined ratio being selected so as to obtain a controlled axial stretching effect or a controlled axial compacting effect on the material of the filter rod (M) as a result of the transition from one conveyor belt to the other, so as to influence the characteristics of the produced filter rod in the required manner.
An apparatus according to claim 5, characterized in that the material forming the filter rod (M) has no outer wrapping sheet,
An apparatus according to claim 5, for producing a filter rod having a structure with a coaxial configuration, comprising an outer layer (R1) of filter material, which has no wrapping sheet, and an inner body in the form of a tube (T) of paper or cardboard, or an inner body of filter material, characterized in that between the upper runs of said at least two conveyor belts (1, 2) a processing station for feeding filter material is interposed, to form said outer layer (R1) of filter material, in that the downstream conveyor belt (2) is in contact with said outer layer (R1) of filter material, and in that the upstream conveyor belt (1) is arranged to advance said inner body consisting of said tube (T) of paper or cardboard, or said inner body of filter material.