WO2018172235A1

WO2018172235A1 - Apparatus and method for producing a wrapped, rod-shaped article

Info

Publication number: WO2018172235A1
Application number: PCT/EP2018/056791
Authority: WO
Inventors: Stefano Malossi; Alberto Monzoni; Antonella Giannini
Original assignee: Philip Morris Products S.A.
Priority date: 2017-03-20
Filing date: 2018-03-19
Publication date: 2018-09-27

Abstract

The apparatus for producing a wrapped, rod-shaped article, includes a concentrically arranged array (20) of ring-shaped elements (30a, 30b, 30c), and a wrapping unit. The ring-shaped elements have differing inner diameters and the ring-shaped elements have an inner surface that in use of the apparatus is in contact with a sheet of material to be formed into the rod-shaped article. In the method a sheet of material (22) is inserted into the first ring-shaped element (30a) provided at an upstream end of the array. The sheet of material is pulled through the array of ring-shaped elements and is output at a downstream end of the array in rod-shaped form. The material is then wrapped with wrapping material in a wrapping unit to form the wrapped, rod-shaped article.

Description

APPARATUS AND METHOD FOR PRODUCING A WRAPPED, ROD-SHAPED ARTICLE

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

Some aerosol generating devices 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 so as to form a continuous tubular rod. This continuous tubular rod is then cut in small rods which are used in the manufacture of aerosol generating articles.

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 polylactic 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 foldings 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 variabilities 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 could be affected by the heat created by the friction due to the high speed contact of the foil material having mechanical resistance to 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 variabilities 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 wrapped, rod-shaped article, said apparatus including a concentrically arranged array of ring- shaped elements and a wrapping unit. The ring-shaped elements have differing inner diameters and the ring-shaped elements have an inner surface that in use of the apparatus is in contact with a sheet of material to be formed into the rod-shaped article.

The apparatus of the present invention allows to progressively compress or fold a continuous sheet of material and to eventually form the material into a wrapped rod-shaped article having desired product properties. The overall contact surface between the sheet of material and the array of ring-shaped elements is reduced as compared with conventional funnel shaped elements, such that less is friction and, thus, less heat is generated. Further, between consecutive ring-shaped elements, the sheet material is free to rearrange itself to decrease stress and to decrease its resistance to compression.

Said inner surface may be realized in ceramic material. The ring-shaped elements may also comprise an inner ring element that is mounted to an outer ring element. The inner ring element may be made from ceramic material.

The ceramic material used for the inner surface of the ring-shaped element or the inner ring element may be a thermally conductive ceramic material. The ceramic material used for the inner surface of the ring-shaped element or the inner ring element may comprise zirconia or alumina.

Ceramic materials have a plurality of desirable properties that can advantageously be utilized in the apparatus of the present invention. These desirable properties include low friction, low thermal expansion, high rigidity and high corrosion resistance. Each of these properties beneficially influences the manufacturing process of forming flat sheet material into a cylindrical rod-shaped article. For example due to its thermal conductivity the frictional heat generated upon pulling and compressing the sheet of material through the ring-shaped elements can be readily dissipated, such that heat damage of the sheet material is substantially prevented.

The inner ring element may be mounted to the outer ring element by any suitable connection technique. In an embodiment the outer diameter of the inner ceramic ring element may correspond to the inner diameter of the outer metal ring element, such that there is a form- fit connection between these ring elements. The ceramic ring may further be held in place by blocking screws. The blocking screws may extend radially through the metal ring and may be provided equidistantly at the outer peripheral diameter of each metal ring.

In an embodiment the blocking screws are not screwed into the inner ceramic ring element, but only contact the downstream side surface of the ceramic ring element. In this configuration the blocking screws prevent displacement of the inner ceramic rings due to friction with the moving sheet of material in use of the apparatus. This configuration has the additional benefit that the ceramic ring structure remains intact, reducing the risk of breach, chip or fissure of the ceramic rings.

The surfaces of the ceramic material in particular the inner surfaces that come into physical contact with the sheet of material, may be round and smooth so as to further decrease friction and to avoid generation of excess heat. The term "smooth" specifies configuring the inner surfaces such that the coefficient of friction between the inner surfaces and the sheet of material is minimized. The coefficient of friction, particularly the sliding/kinetic friction μ_κ, between the inner surfaces of the ceramic material and the sheet of material is preferably lower than 0.1 , more preferably lower than 0.01 . By providing a smooth material, less heat is generated when the sheet of material runs through the ring-shaped elements. Also, the smooth material is less prone to material defects and abrasive wear.

In order to further promote heat dissipation, the material of the outer ring element may also be made from thermally conductive material. Suitable materials for the outer ring element include metallic materials, such as aluminum and copper. These materials are not only good heat conductors, but are at the same time well machinable such that ring-shaped elements can be readily mounted to the remainder of the apparatus.

The ring-shaped elements may be adjustably mounted to a rail which extends in parallel to the processing direction of the sheet of material through the apparatus. The ring-shaped elements may be mounted to the rail via a screw connection. The ring-shaped elements may comprise a threaded pin. The threaded pin may be mounted in a corresponding bore provided in the rail. The skilled person may equally employ other suitable fixing means in order to mount the ring-shaped elements to the guide rail.

The size and the number of ring-shaped elements implemented in the array may be adapted to the individual manufacturing requirements. The array may comprise at least two ring- shaped elements. The array may comprise at least three ring-shaped elements. The array may comprise two, three, four, five or more ring-shaped elements. The width of all ring-shaped elements may be identical and may be below 30 millimeters. The width of the ring-shaped elements may amount to between 5 and 20 millimeters. The width of the ring-shaped elements may amount to about 12 millimeters. The width of the ring-shaped elements is defined along a longitudinal axis of the ring-shaped elements, wherein the longitudinal axis extends through the center of the elements along the processing direction of the sheet of material.

If the ring-shaped elements comprise an inner ceramic ring and an outer metallic ring, the above mentioned width dimensions may equally apply to the width of the outer ring elements. The ceramic inner ring elements may have the same width as the outer ring elements. Alternatively the ceramic inner ring elements may have a smaller width as the outer ring elements such as to decrease the contact surface between the inner ring elements and the sheet of material.

The inner diameter of the ring-shaped elements may decrease from the upstream end of the array towards the downstream end of the array. The decrease of the inner diameter may follow any other desired profile, which is considered to be most suitable for the specific material to be processed. The inner diameter may decrease linearly from the upstream end to the downstream end of the array.

The inner diameter of the smallest ring-shaped element of the array corresponds to the desired diameter of the rod-shaped article, which typically amounts to between 5 and 15 millimeters. The inner diameter of the largest ring-shaped element provided at the upstream end of the array may range between 20 and 150 millimeters, between 40 and 100 millimeters or between 50 and 80 millimeters.

The inner diameters of any intermediate ring-shaped elements may therefore also vary between 5 and 150 millimeters. In an embodiment of the invention array may consist of three ring-shaped elements with the upstream ring-shaped element having an inner diameter of between 40 and 60 millimeters, the intermediate ring-shaped element having an inner diameter of between 25 and 35 millimeters, and the downstream ring-shaped element having an inner diameter of between 8 and 12 millimeters.

The overall length of the array along the longitudinal axis of the array may amount to between 10 millimeters and 300 millimeters. The length depends on the number of and the distance between the ring-shaped elements.

The distance between the ring-shaped elements along the longitudinal axis of the array may be adjusted to amount to between 30 millimeters and 100 millimeters, and may be adjusted to amount to between 50 millimeters and 80 millimeters. The distance between the ring-shaped elements may be equal, but may also be unequal. In order to adjust the distance between the ring-shaped elements, the longitudinal rail may comprise a plurality of bores to which the ring- shaped elements may be fixed. Alternatively, the longitudinal rail may also comprise one or more longitudinal slots. The ring-shaped elements may be fixed at any desired positions along the longitudinal slot of the rail.

The number and size of and the distance between the ring-shaped elements may be adapted to the specifics of the material to be processed or depending on any desired effects of the manufacturing method. For example these parameters may influence the folding and compression pattern of the sheet material to be processed and may therefore be used for adjusting key parameters of the resulting product such as the resistance to draw (RTD).

One advantage of the present invention with respect to the conventionally used funnel shaped rod forming devices is that the sum of the surfaces that are in contact with the sheet material is reduced. A measure for the reduction of the contact surfaces is the ratio between the width of the ring-shaped elements and the distance between the ring-shaped elements. This ratio between the width of the ring-shaped elements and the distance between the ring-shaped elements may be larger than 1 :1 , may amount to between 1 :1 and 1 :5, and may amount to about 1 :3.

The apparatus may comprise a cooling system. The cooling system may be a liquid cooling system. The liquid cooling system may be provided to the longitudinal rail to which the ring-shaped elements are mounted. The cooling system may also be provided directly to the ring-shaped elements. The cooling system may support heat dissipation and may therefore prevent or reduce any detrimental effects on the final rod-shaped product caused by application of excessive heat.

According to a second aspect, the invention also relates to a method for producing a wrapped, rod-shaped article. The method includes the steps of providing a sheet of material and providing a concentrically arranged array of ring-shaped elements defining a passageway for the sheet of material. The ring-shaped elements have differing inner diameters. The method further comprises the steps of inserting the sheet of material into the first ring-shaped element provided at the upstream end of the array, outputting the rod-shaped article from the last ring- shaped element provided at the downstream end of the array and wrapping the rod-shaped article in a wrapping unit.

Features described in context of one aspect of the invention may equally be applied to other aspects of the invention.

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

Fig. 1 shows a prior art filter rod forming device;

Fig. 2 shows an array of ring-shaped elements in accordance with the present invention; Fig. 3 shows the array of Fig.2 from a different angle and provided with a PLA sheet;

Fig. 1 shows a conventional filter rod forming device comprising a filter material converging device 1 which compresses filter material into a rod form. The converging device 1 comprises a funnel shaped portion 1 1 with an inlet 10 and an outlet 1 1 1 , and further comprises a garniture tongue, which guides the filter material in the final stage before it forms a rod at the outlet of the garniture tongue. Filter material such as cellulose acetate tow may be drawn from a bale. The filter material may be bloomed, for example, where the filter material is cellulose acetate tow. Alternatively, where the filter material is a flat web material, for example a paper or plastic web, such as polylactic acid, the filter material may be first crimped to allow transversal gathering of the web. Then, the filter material is converged in the converging device and is fluffed by the injection of compressed air supplied to the converging device. Excess air can exit the converging device via openings 1 10. After the filter material has passed the converging device, it enters the garniture tongue, where it is further compressed and formed into the desired rod shape. Additionally, a liquid introduction device 2 is integrated into the funnel shaped portion 1 1 of the converging device 1 . The liquid introduction device may provide flavored liquid via needle portion 15 to the rod of filter material. For the above mentioned reasons conventional devices may not be suitable for processing materials having a relative high mechanical resistance to compression or for processing heat sensitive materials.

Figs. 2 and 3 show an array 20 of ring-shaped elements 30 a,b,c to be used in an apparatus of the present invention. A sheet of material 22, which may be made from polylactic acid, is pulled through array 20 along the processing direction indicated by arrow 24 in Fig. 2. As the sheet of material 22 is pulled through the ring-shaped elements 30 a,b,c with continuously decreasing diameters, the sheet of material 22 is compressed and formed into the desired rod shape. Downstream from array 20 a wrapping unit (wrapping unit not shown) is provided. In the wrapping unit wrapping material is applied to the rod-shaped material 22.

The array 20 of ring-shaped elements 30 a,b,c comprises three ring-shaped elements 30 a,b,c which are concentrically arranged and have continuously decreasing inner diameters with respect to the processing direction. Each ring-shaped element 30 a,b,c comprises an inner ceramic ring 32 a,b,c. Each ceramic ring 32 a,b,c is mounted to an outer metal ring 34 a,b,c. The outer diameter of the ceramic rings corresponds to the inner diameter of the outer metal rings, such that there is a form-fit connection between these rings. Each ceramic ring 32 a,b,c is held within the corresponding metal ring 34 a,b,c by three blocking screws 36. The blocking screws 36 extend radially through the metal rings 34 a,b,c and are provided equidistantly at the outer peripheral diameter of each metal ring 34 a,b,c.

In the embodiment depicted in Fig. 2 and 3 the blocking screws 36 are not screwed into the ceramic rings 32 a,b,c, but only contact the peripheral surfaces of the ceramic rings 32 a,b,c. In this way it is ensured that the ceramic ring structure remains intact, reducing the risk of breach, chip or fissure of the ceramic rings 32 a,b,c.

The inner surfaces of the ceramic rings 32 a,b,c, which are the surfaces that come into contact with the foil material, are round and smooth so as to decrease friction between the ceramic rings 32 a,b,c and the sheet material 22.

Each metal ring 34 a,b,c is mounted to a metallic rail 40 via an adjustable screw connection. The metallic rail 40 comprises a series of slots 42 which extend in parallel to the processing direction 24 of the sheet material 22 to be processed. In this way it is possible to align the ring-shaped elements 30 a,b,c concentrically along the rail. Further, the slots 42 allow to vary and to adjust the distance between the ring-shaped elements 30 a,b,c as desired or demanded by the respective processual needs.

The ceramic material used for the inner ceramic rings 32 a,b,c is a thermally conductive alumina ceramic which helps the sheet material 22 to dissipate the heat of the compression and prevents heat damage on the sheet material 22. The metal rings 34 a,b,c and the rail 40 are made from aluminum, which is also a good thermal conductor.

In the depicted embodiment the ceramic rings 32 a,b,c are assembled so that the ceramic rings 32 a,b,c are aligned concentrically and in a sequence that, with respect to the processing direction 24 of the sheet material 22, goes progressively from a larger inner diameter to a smaller inner diameter. In the specific example shown in Figs. 2 and 3, the rings 30 a,b,c are provided equidistantly with a separation of 60 millimeters along the metal rail 40. The inner diameter of the largest ceramic ring 32a provided at the upstream end of the array 20 amounts to 50 millimeters, the inner diameter of the intermediate ceramic ring 32b amounts to 30 millimeters and the inner diameter of the smallest ceramic ring 32c provided at the downstream end of the array 20 amounts to 10 millimeters. Thus the resulting rod-shaped element that is output from the array 20 of ring-shaped elements 30 a,b,c has also a diameter of 10 millimeters, which corresponds to the inner diameter of the smallest ceramic ring 32c of the array 20.

The rod-shaped element is then provided to a conventional wrapping unit (not shown in the figures) in which a wrapping material, typically a wrapping paper is wrapped around the rod- shaped element. In further processing steps, the wrapped rod-shaped element may be cut in smaller elements and may be used as components in an aerosol generating article.

Claims

1 . Apparatus for producing a wrapped, rod-shaped article, said apparatus including:

- a concentrically arranged array of ring-shaped elements, and

- a wrapping unit

wherein the ring-shaped elements have differing inner diameters, and wherein the ring- shaped elements have an inner surface that in use of the apparatus is in contact with a sheet of material to be formed into the rod-shaped article.

2. Apparatus according to claim 1 , wherein the inner diameter of the smallest ring- shaped element of the array corresponds to the desired diameter of the rod-shaped article.

3. Apparatus according to any of the preceding claims, wherein said inner surface of each of the ring-shaped elements is realized in ceramic material.

4. Apparatus according to claim 3, wherein each of said ring-shaped elements comprises an inner ring element made from ceramic material which is mounted to an outer ring element made from metallic material.

5. Apparatus according to any of claims 3 or 4, wherein the ceramic material is a thermally conductive material such as zirconia or alumina.

6. Apparatus according to any of claims 3 to 5, wherein the inner surfaces of the ceramic material are round and smooth so as to decrease friction.

7. Apparatus according to any of the preceding claims, wherein each of said ring-shaped elements is adjustably mounted to a rail and wherein the rail extends parallel to a processing direction of wrapping unit

8. Apparatus according to any of the preceding claims, wherein the ratio between the width of the ring-shaped elements and the distance between the ring-shaped elements is larger than 1 :1 , amounts to between 1 :1 and 1 :5, or amounts to about 1 :3.

9. Apparatus according to any of the preceding claims, wherein the array consists of three concentrically arranged ring-shaped elements and wherein the inner diameter of the ring- shaped elements decreases linearly from the upstream end to the downstream end of the array.

10. Apparatus according to any of the preceding claims, wherein the distance between the ring-shaped elements along the longitudinal axis of the array may be adjusted to amount to between 50 millimeters and 80 millimeters.

1 1 . Apparatus according to any of the preceding claims, wherein the array consists of three ring-shaped elements.

12. Apparatus according to claim 1 1 , wherein

the first ring-shaped element has an inner diameter of between 40 and 60 millimeters, the second first ring-shaped element has an inner diameter of between 25 and 30 millimeters, and

the third ring-shaped element has an inner diameter of between 8 and 12 millimeters.

13. Apparatus according to any of the preceding claims, wherein the metallic outer ring elements are liquid cooled.

14. Method to produce a wrapped, rod-shaped article, said method including:

providing a sheet of material,

providing a concentrically arranged array of ring-shaped elements defining a passageway for the sheet of material,

inserting the sheet of material into the first ring-shaped element provided at the upstream end of the array,

outputting the rod-shaped element from the last ring-shaped element provided at the downstream end of the array,

wrapping the rod-shaped element in a wrapping unit to form a wrapped rod-shaped article,

wherein the ring-shaped elements have differing inner diameters.

15. Method according to claim 14,

wherein the diameters of the ring-shaped elements continuously decrease from the upstream end towards the downstream end of the array.