WO2018122301A1

WO2018122301A1 - Apparatus and method for producing a rod shaped article

Info

Publication number: WO2018122301A1
Application number: PCT/EP2017/084703
Authority: WO
Inventors: Roberto GHERARDINI
Original assignee: Philip Morris Products S.A.
Priority date: 2016-12-29
Filing date: 2017-12-28
Publication date: 2018-07-05

Abstract

The invention relates to an apparatus and a method for producing a rod-shaped article from a sheet of material (2), said apparatus including: - a first tubular element (11) defining a longitudinal axis and having a first inlet (14) to introduce the sheet and a first outlet (15) to output the rod-shaped article (1), said first inlet and first outlet being connected by a first passageway (16), wherein said first passageway has a non-circular constant cross section; - a twisting device adapted to rotate the first tubular element around said longitudinal axis at a first speed; - wherein the twisting device is adapted so that rotation thereof causes compression of the sheet of material into the rod shaped article.

Description

APPARATUS AND METHOD FOR PRODUCING A ROD SHAPED ARTICLE

The present invention relates to a method and an apparatus for producing a rod shaped article, for example a component of an aerosol-generating device.

Some smoking articles have at least one part made by filling a continuous band of wrapping paper with a material, then by closing the wrapping paper around the material to form a continuous tubular rod . This continuous tubular rod is then cut in "small" rods, which are the indicated smoking articles parts.

Prior to the stage where the material is put on the wrapping paper, the material overall shape has to be transformed from a raw material usually handled at the beginning of the manufacturing process in a foil shape, to a material that can fit into a tubular rod, generally of less than about 1 centimeter in diameter.

To do so, the foil material usually goes though different stages, among which a critical "compression" step is included, where the foil material enters at high speed into a funnel-shaped device that compresses the foil material into a compressed rod having a diameter close to the one of the final tubular rod .

Some materials, for instance Poly Lactic Acid (PLA), are difficult to handle in such process because they have relative high mechanical resistant to compression . Due to this, the compression of the material inside the funnel- shaped device is not a controlled process. The result of the increasing pressure of the funnel-shaped device on the PLA foil running freely at high speed inside it could create chaotic folding and turbulences in the material. Accordingly, the compression inside the funnel-shaped device of the foil material creates compressed rods the internal structure of which can greatly change substantially in an unpredictable manner. This may affect the characteristics of the smoking part and may introduce variability in different properties of the smoking part, including in the resistance to draw (RTD), as well as in the rod geometry, such as the presence of ovality or changes in diameter, and so affect the product consistency or may create products that lay outside the desired specifications.

Furthermore, some material, for instance PLA again, could be quite sensitive to heat and so it could be affected by the heat created by the friction due to the high speed contact of the foil material having mechanical resistance to

l compression with the material of the funnel-like device, along the length of the funnel-like device which is usually between about 15 centimeters and about 30 centimeters long. Such problem could result in constraints to the maximum speed of the production line or variability of the properties of the end product. It would be desirable to have an apparatus and a method with which it is possible to have more control on the final result in the compressing step even when using materials that are sensible to heat or have strong mechanical resistances.

According to a first aspect, the invention relates to an apparatus for producing a rod-shaped article from a sheet of material, said apparatus including : a first tubular element defining a longitudinal axis and having a first inlet to introduce the sheet and a first outlet to output the rod-shaped article, said first inlet and first outlet being connected by a first passageway, wherein said first passageway has a non-circular constant cross section; and a twisting device adapted to rotate the first tubular element around said longitudinal axis at a first speed.

Preferably, the invention refers to an apparatus for producing a rod-shaped article from a sheet of material, said apparatus including : a first tubular element defining a longitudinal axis and having a first inlet to introduce the sheet and a first outlet to output the rod-shaped article, said first inlet and first outlet being connected by a first passageway, wherein said first passageway has a non- circular constant cross section; a twisting device adapted to rotate the first tubular element around said longitudinal axis at a first speed; wherein the twisting device is adapted so that rotation thereof causes compression of the sheet of material into the rod shaped article. The apparatus of the invention includes a tubular element which functions as twisting device, turning around a longitudinal axis, which preferably is the same as the direction of transport of the material to be compressed, so that the material entering into the devices as a sheet is twisted by the devices to a twisted rod-shaped article. Twisting a material to make it fits into a tubular element is a better controlled process than a process in which the material is compress it through a funnel-shaped device. Furthermore, rotating the sheet of material in a tubular device which might have a relatively small length, decreases the friction effects between the sheet and the tubular element. Due to the above, by using the apparatus of the invention, a stable process may be obtained, reaching a more consistent final product, such as an aerosol generating article including a part of the rod shaped article obtained using the invention . A more consistent final product may lead to a repeatable smoking experiences and to a related stability and repeatability of deliveries, for example nicotine delivery, as well as stability of resistance to draw (RTD) and overall repeatability of the sensorial experience during the aerosol generating article consumption. Further, during the twisting, that is, during rotation around an axis, also compression of the material is obtained, so that the material is compressed into a rod without the need of a further funnel to compress the twisted material. Less components and steps are therefore needed to obtain the final product.

Preferably, the rod shaped article is a component of an aerosol-generating article.

In the following, with "rod" a substantially rod shaped element is indicated, however its cross section does not need to be circular, any cross section is possible.

Further, the rod shaped article defines a longitudinal axis, meaning that one of its dimension is longer than the other two. The longitudinal axis is the axis along the longer dimension. Preferably, cross sections taken perpendicularly to the longitudinal axis are substantially identical in area, however different configurations can be present as well.

In the following, with the term "components" any element which may be included in an aerosol-generating article is meant. Such elements are known in the art and not further detailed below. For example, such component might include a plug of a filter, a heat source, a menthol capsule, a charcoal element, and so on.

As used herein, aerosol-generating article is any article that generates an inhalable aerosol when an aerosol-forming substrate is heated . The term includes articles that comprise an aerosol-forming substrate that is heated by and external heat source, such as an electric heating element. An aerosol- generating article may be a non-combustible aerosol-generating article, which is an article that releases volatile compounds without the combustion of the aerosol-forming substrate. An aerosol-generating article may be a heated aerosol-generating article, which is an aerosol-generating article comprising an aerosol-forming substrate that is intended to be heated rather than combusted in order to release volatile compounds that can form an aerosol. The term includes articles that comprise an aerosol forming substrate and an integral heat source, for example a combustible heat source. An aerosol-generating article may be a smoking article that generates an aerosol that is directly inhalable into a user's lungs through the user's mouth. An aerosol-generating article may resemble a conventional smoking article, such as a cigarette and may comprise tobacco. An aerosol-generating article may be disposable. An aerosol-generating article may alternatively be partially- reusable and comprise a replenishable or replaceable aerosol-forming substrate.

In preferred embodiments, the aerosol-generating article may be substantially cylindrical in shape. The aerosol-generating article may be substantially elongate. The aerosol-generating article may have a length and a circumference substantially perpendicular to the length. The aerosol-generating article may have a total length between approximately 30 mm and approximately 100 mm. The aerosol-generating article may have an external diameter between approximately 5 mm and approximately 12 mm.

As used herein, the term "sheet" denotes a laminar element having a width and length substantially greater than the thickness thereof. The width of a sheet is preferably greater than 10 millimeters, more preferably greater than 20 millimeters or 30 millimeters. Even more preferably, the width of the sheet is comprised between about 100 millimeters and 500 millimeters. Preferably, the thickness of the sheet is comprised between about 20 micrometers and about 50 micrometers. The sheet of material used in forming the rod shaped article maybe any material common in the industry of aerosol generating articles. For example, it might be a plastic material sheet, such as poly lactic acid (PLA), a polyester sheet, a tobacco sheet, a paper sheet, an aluminium sheet or a cellulose acetate sheet. Preferably, the sheet is a poly lactic acid sheet.

The apparatus includes a first tubular element including an inlet where the sheet is inserted and an outlet, the inlet and the outlet being connected by a passageway. The first tubular element, preferably the passageway, is defining a longitudinal axis, connecting inlet and outlet. Preferably, the longitudinal axis is parallel to and even more preferably coincides to the direction of transport of the sheet. For example, the apparatus might also include a transport device apt to transport the sheet along a first direction, which is parallel to the longitudinal axis of the tubular element. The inlet and the outlet of the tubular device have a non-circular shape. The shape of the inlet and the outlet remains identical through the whole length of the passageway. Taking a cross section of the tubular element along a plane perpendicular to its longitudinal axis gives as a result an opening having the same shape regardless of where the plane cuts the tubular element, as long as parallel cutting planes are considered. This opening has the same shape as the inlet or the outlet. Preferably, an inner surface of the passageway connecting the inlet and the outlet is such that all its generatrices are perpendicular to an edge curve defining the shape of the inlet or outlet. Further, the apparatus includes a twisting device which rotates the first tubular element at a first speed. This speed may be constant or changeable. Further, the direction of rotation may be changeable as well. The rotation takes place around the longitudinal axis of the tubular device.

At the outlet of the first tubular device, the rod shaped article exits, in order to be further processed .

The non-circular shape of the cross section of the passageway of the tubular device combined with the rotation of the tubular device allow to have a good grip on the material forming the sheet so that turning the first tubular device efficiently twists the material. A good control of the process to form the rod from a sheet of material is achieved . Preferably, the apparatus includes a wrapping unit located downstream the tubular element to wrap the rod-shaped article in a wrapping sheet. Often, components for aerosol forming articles are wrapped in a wrapping sheet such as wrapping paper. Preferably, the rod shaped article becomes a component of an aerosol generating article and therefore it is preferably wrapped .

During the twisting of the twisting device, compression takes place. That is, the twisting device is configured to compress the sheet of material . Therefore, preferably no further compression steps are needed, for example there is no funnel at the outlet of the compression device. Preferably, the apparatus comprises a second tubular element located downstream the first tubular element, the second tubular element having a second longitudinal axis and having a second inlet to introduce the rod shaped article exiting the first tubular element and a second outlet to output the rod- shaped article, said second inlet and second outlet being connected by a second passageway, wherein said second passageway has a non-circular constant cross section. Preferably, more tubular elements may be introduced in order to progressively twist the sheet, in order to obtain a better twisting or to obtain the twisting in a less "aggressive" manner. The cross section of the first tubular element and of the second tubular element may be the same or different. Preferably, the longitudinal axis of the first and the second tubular element are parallel and more preferably they coincide. Even more preferably, the longitudinal axes of the first and second tubular element are parallel to the direction of transport of the sheet.

More preferably, an area of the cross section of the second passageway is smaller than an area of the cross section of the first passageway. In this way, a twisting in steps of the sheet of material is obtained, reducing the stress withstand by the sheet. The final twisting to obtain the rod shaped article having a desired diameter is made only after an intermediate twisting to obtain an intermediate rod shaped article having an intermediate diameter. More preferably, the apparatus includes a second twisting device adapted to rotate the second tubular element around said longitudinal axis at a second speed, different from the first speed. For example, considering the second tubular element downstream the first tubular element in the direction of transport of the sheet, the speed of rotation may increase from the first tubular element in which the sheet enters to the second tubular element from which the rod shaped article exits. The rotational or angular speed of the second tubular element is thus higher than the rotational or angular speed of the first tubular element. A progressive and less aggressive twisting is thus achieved .

Preferably, said passageway has an inner surface and said inner surface is realized in ceramic material . The parts of the apparatus in contact with the high speed running sheet are preferably chosen so as to decrease the effect of the friction.

Preferably, said twisting device is turnable so that it rotates the first tubular element with a changeable first speed or changeable direction of rotation. The speed or the direction of rotation may be changed depending on the desired final product. Preferably, said cross section of said first passageway includes a polygon.

Preferably, said cross section of said first passageway includes a protrusion.

Many shapes are possible as cross sections of the passageway as long as they are non-circular. The cross section may define an elongate shape, such as an S-shape or a parenthesis-shape, an eight shape, or a wider shape such as a rectangular shape, a triangle, etc.

Preferably, a length along the longitudinal axis of the first tubular element is comprised between about 5 millimeters and about 300 millimeters. Preferably, due to the fact that the compression is made by twisting the sheet and not by progressively pressing on the sheet, the length of the tubular element (either first or second) of the invention could be as small as possible, which will also decrease the friction experienced by the sheet.

According to a second aspect, the invention relates to a method to produce a rod-shaped article from a sheet of material, said method including : inserting a sheet into an inlet of a first tubular element; transporting said sheet in a first passageway of the first tubular element, wherein said first passageway has a non-circular constant cross section, so as to form a rod-shaped article; rotating first the tubular element while transporting the sheet into the first passageway; and outputting the rod-shaped article from an outlet of the first tubular element.

Preferably, the invention also refers to a method to produce a rod-shaped article from a sheet of material, said method including : inserting a sheet into an inlet of a first tubular element; transporting said sheet in a first passageway of the first tubular element, wherein said first passageway has a non-circular constant cross section, so as to form a rod-shaped article; rotating first the tubular element while transporting the sheet into the first passageway; compressing the sheet of material into the rod shaped article while rotating; and outputting the rod-shaped article from an outlet of the first tubular element.

The advantages of the second aspect of the invention have been already listed with respect to the first aspect and therefore are not repeated herein.

Preferably, the method includes providing a second tubular element in series downstream the first tubular element along a direction of transport, an area of a cross section of a second passageway of the second tubular element being smaller than an area of the cross section of the first tubular element.

Preferably, the method includes wrapping the rod shaped article in a wrapping sheet.

More preferably, the method includes setting a rotational speed of the first tubular element or a direction of rotation of the first tubular element depending on a distance between the first tubular element and a wrapping unit. Several tubular elements could be used one after the other, each connected to the same motor or each having an independent motor, so that each motor is allowed to have a specific rotating speed or turn in a specific direction independently from the other motors. The operator could adjust these parameters (e.g. speed, direction of rotation) and so, according to the speed of the sheet as well as the distance from the wrapping unit, can determine the number of twists the sheet will have.

Preferably, the method includes pre-tensioning the foil upstream the first tubular element. Because the inlet of the first tubular element is much smaller than the width of the sheet, the sheet is preferably pushed or folded to pass through the opening entering the first tubular element at the start of the process. So as to prevent the foil to retroactively refold up before the first tubular element, and so modifying the nature of the sheet before the first tubular element and possibly impacting the rod-shaped article outputted, a pre- tensioning of the sheet is preferred upstream the first tubular element. The pre- tensioning can be obtained for example by a roller.

Preferably, the method includes pulling or pushing the sheet in the first tubular element. Preferably, in order to enter the first tubular element, the sheet needs to be either pulled out of it, for example from the outlet side, or pushed in. This action can be performed for example by means of one or more rollers.

The invention will be further described, by way of example only, with reference to the accompanying drawings in which :

Figure 1 is a perspective view of an apparatus realized according to the present invention; - Figure 2 is a perspective view of an additional embodiment of the apparatus of Figure 1 ;

Figure 3 is a side view in section of a detail of the apparatus of Figure 1 or 2;

Figure 4 is a perspective view of an embodiment of the detail of the apparatus of Figure 3; and

Figures 5 - 16 are front views of additional embodiments of the detail of Figure 3 or 4.

In figure 1 and 2, an apparatus for the production of rod shaped articles is depicted and globally indicated with 10. The apparatus 10 is adapted to obtain a rod-shaped article 1, such as a filter component, from a sheet 2 or foil of material, such as PLA.

The apparatus 10 includes a first tubular element 11 which is rotatable by a motor 12 connected to the tubular element via a belt 13. The speed and the direction of rotation can be tunable. The first tubular element 11 includes an inlet 14 and an outlet 15 and a passageway 16 (see figure 3) connecting the inlet and the outlet. The passageway 16 defines a longitudinal axis X which is preferably the same as a direction of transport of the sheet 2 inside the tubular element. The direction of transport is indicated with an arrow 19 in figure 3. The passageway has a constant cross section, as depicted in figure 3. Cross sections taken along planes perpendicular to the longitudinal axis X and taken in different positions lead to shapes one identical to the other. The lines forming an inner surface 17 of the passageway 16 are perpendicular to the inlet 14 and outlet 15. An outer surface 18 of the tubular element can have any shape.

Examples of shapes of cross sections of the passageway 16 along a plane perpendicular to the longitudinal axis X, which is the same as the shape of the inlet or of the outlet, are given in figures 4 - 16. The shape of the cross section can be any, as long as it is not circular. Two groups of cross sections can be identified : in a first group of figures 4 - 10 the area defined by the passageway in a neighbourhood of its center, where the center is defined as the location of the longitudinal axis, is "small", and a second group (figures 11- 16) where the size of such an area is "large". The area of a neighbourhood is defined as the area of the biggest circle centered in the longitudinal axis which can be housed in the passageway. In the first group, the cross section has a rather elongated shape. The shape of the cross section can be a slit (Figs. 6,5), a rhombus (Fig . 7), an S (Fig. 8), a star (Fig. 9) or an eight (Fig. 10). Preferably, the length of the first tubular element of the first group is comprised between about 50 millimeters and about 220 millimeters. In the second group, the shape can be a star (Figs. 11, 12, 13, 15), a triangle (Fig. 14), a square (Fig . 16). Preferably, the length of the first tubular element of the second group is comprised between about 65 millimeters and about 250 millimeters. With shape of the cross section it is meant the shape formed by an edge of the opening identifying the passageway and defined in the cross section. As shown in Figure 2, two or more different tubular elements, such as a first tubular element 11 and a second tubular element 21 can be positioned in series along the direction of travel 19 of the sheet 2. Each tubular element 11, 21 is connected to a different motor, therefore its direction of rotation and speed can be independently controlled . The first and second tubular elements 11, 21 can have the same cross section or different ones.

In operation, the sheet of material 2 is inserted in the first tubular element 11, for example pushing or pulling the same. The first tubular element 11 is rotated at a desired first speed and thus the sheet 2 becomes twisted, thanks to the non-circular cross section of the passageway.

In case of more than a tubular element, the twisting can be performed in steps, properly choosing the cross section of the tubular elements and their speed .

Compression of the sheet of material 2 takes place during the twisting, No additional compression steps or a compression element, like a funnel, is needed in the method or apparatus of the invention. The correct amount of compression takes place thanks to the twisting device.

The outputted rod shaped article 1 can be then for example wrapped in a wrapping unit 30and possibly cut in smaller elements to be used as components in an aerosol generating article (not shown in the drawings). The speed of rotation may be dependent on the distance between the tubular element and the wrapping unit 30.

Claims

Apparatus for producing a rod-shaped article from a sheet of material, said apparatus including :

- a first tubular element defining a longitudinal axis and having a first inlet to introduce the sheet and a first outlet to output the rod-shaped article, said first inlet and first outlet being connected by a first passageway, wherein said first passageway has a non-circular constant cross section;

- a twisting device adapted to rotate the first tubular element around said longitudinal axis at a first speed;

- wherein the twisting device is adapted so that rotation thereof causes compression of the sheet of material into the rod shaped article.

Apparatus according to claim 1, including a wrapping unit located downstream the tubular element to wrap the rod-shaped article in a wrapping sheet.

Apparatus according to claim 1 or 2, including a second tubular element located downstream the first tubular element, the second tubular element having a second longitudinal axis and having a second inlet to introduce the rod shaped article exiting the first tubular element and a second outlet to output the rod-shaped article, said second inlet and second outlet being connected by a second passageway, wherein said second passageway has a non-circular constant cross section .

Apparatus according to claim 3, wherein an area of the cross section of the second passageway is smaller than an area of the cross section of the first passageway.

Apparatus according to claim 3 or 4, including a second twisting device adapted to rotate the second tubular element around said longitudinal axis at a second speed, different from the first speed .

Apparatus according to any of the preceding claims, wherein said passageway has an inner surface and said inner surface is realized in ceramic material .

7. Apparatus according to any of the preceding claims, wherein said twisting device is tunable so that it rotates the first tubular element with a changeable first speed or changeable direction of rotation.

8. Apparatus according to any of the preceding claims, wherein said cross section of said first passageway includes a polygon.

9. Apparatus according to any of the preceding claims, wherein said cross section of said first passageway includes a protrusion.

10. Apparatus according to any of the preceding claims, wherein a length along the longitudinal axis of the first tubular element is comprised between about 5 millimeters and about 300 millimeters.

11. Method to produce a rod-shaped article from a sheet of material, said method including :

inserting a sheet into an inlet of a first tubular element;

- transporting said sheet in a first passageway of the first tubular element, wherein said first passageway has a non-circular constant cross section, so as to form a rod-shaped article;

rotating first the tubular element while transporting the sheet into the first passageway;

- compressing the sheet of material into the rod shaped article while rotating; and

- outputting the rod-shaped article from an outlet of the first tubular element.

12. The method according to claim 11, including :

providing a second tubular element in series downstream the first tubular element along a direction of transport, an area of a cross section of a second passageway of the second tubular element being smaller than an area of the cross section of the first tubular element.

13. The method according to claim 11 or 12, including :

- wrapping the rod shaped article in a wrapping sheet.

14. The method according to claim 13, including :

- setting a rotational speed of the first tubular element or a direction of rotation of the first tubular element depending on a distance between the first tubular element and a wrapping unit.

15. The method according to one or more of claims 11 - 14, including : pre-tensioning the foil upstream the first tubular element.

16. The method according to one or more claims 11 - 15, including the step of:

Pulling or pushing the sheet in the first tubular element.