WO2000015058A1

WO2000015058A1 - Improved multiple cavity filter

Info

Publication number: WO2000015058A1
Application number: PCT/IT1999/000288
Authority: WO
Inventors: Aldo Gerola
Original assignee: Filtrati S.P.A.
Priority date: 1998-09-14
Filing date: 1999-09-14
Publication date: 2000-03-23
Also published as: AU5884099A; IT1302327B1; ITRM980590A1

Abstract

The invention relates to an improved multiple cavity (4) filter (2) comprising at least a first filter length (3) and a second filter lengths (3), at least a cavity (4) between said first and second filter lengths (3), a first paper (6), partially externally enclosing said first and second filter lengths (3), as well as said cavity (4), leaving an upper filling opening, filling material (5) to be introduced within said cavity (4) through said opening created by said first paper (6), and a second paper (7), outer with respect to said first paper (6), completely wrapping said first inner paper (6) and said first and second filter lenghts (3), and said cavity (4).

Description

IMPROVED MULTIPLE CAVITY FILTER

The present invention relates to an improved multiple cavity filter. More specifically, the invention concerns a cigarette fiiter of the above kind, realised in such a way to obtain an optimum filling of the cavity with the desired substance (activated carbons, etc.).

Before proceeding with the present description, it is wished to point out that for the purposes of the invention, the material by which the filter length, the outer paper are realised, as well as the number of cavities provided in a single filter, does not constitute a limitation of the inventive filter, since the solution according to the present invention provides a filter structure that will be described in the following and that allows to obviate to some drawbacks of some multiple cavity filters already available on the market.

Furthermore, in the specification and claims that will follow a reference to the single filter will be made, and as it will better specified said single filter is manufactured as a filter assembly or rod, but is used as single element in the final product (cigarette). As it is well known, special filters exist for particular kind of cigarettes, which are known as "multiple cavity filters", wherein "multiple" means that they perform different filtering actions, while "cavity" means that they provide at least one cavity within which filtering material (e.g. activated carbons, etc.) or aromatising (e.g. menthol, etc.) is introduced. Said filters are manufactured by standard manufacturing techniques, providing a series of filter lengths made up of cellulose acetate, or other suitable and required material for the specific use, spaced by gaps creating said cavities when the assembly is wrapped by the outer paper. A single filter rod provides a plurality of filters that will be then separated to obtain the single filters.

At present, along the multiple cavity filter manufacturing line, single filter lengths are placed at a suitable distance on the paper, and the outer paper is partially wrapped until closing more the half of the filter length circumference.

Now, the filling of the cavity by the specific substance is carried out. It is evident that the filling can be limited to the volume of the cavity wound by the outer paper, since in case this limit is passed, the risk exists that the material, usually granules, goes out of the cavity, placing between the outer paper and the filter length, so that the final filter rod, after the complete closure of the outer paper, cannot be used, since the filter will have spread granules out of the cavity.

The direct consequence of said limitation is that of being able to fill the cavity at a percentage of its whole volume corresponding to about 50%. This aspect is a limitation to the functionality of the same filter.

Different solutions exist in order to solve the above problem, mainly aimed to modify the step of feeding the substance within the cavity.

Mainly, they are solution requiring important and consequently complicated and expensive modification to the manufacturing line. Therefore, specific object of the present invention is that of providing a solution to the above mentioned drawback, allowing to reach very high filling rate of the cavity volume.

Furthermore, object of the invention is that of providing a solution extremely simple, cheap and that does not require substantial modifications to the manufacturing lines presently employed.

These and other results are obtained according to the present invention by the realisation of a filter providing a first inner paper, partially enclosing the filter lengths and defining an opening of the cavity that will allow the filling of the same cavity, and a second outer paper completely surrounding the filter lengths.

It is therefore specific object of the present invention an improved multiple cavity filter comprising at least a first filter length and a second filter length, at least a cavity between said first and second filter lengths, a first paper, partially externally enclosing said first and second filter lengths, as well as said cavity, leaving an upper filling opening, filling material to be introduced within said cavity through said opening created by said first paper, and a second paper, outer with respect to said first paper, completely wrapping said first inner paper and said first and second filter lengths, and said cavity. Preferably, according to the invention, said at least first and second filter lengths are comprised of cellulose acetate and/or pure cellulose or other suitable materials. Furthermore, according to the invention, said first and second wrapping papers can be comprised of the same material or of different materials.

Always according to the invention, said filter can provide a plurality of cavities between a plurality of filter lengths.

Still according to the invention, said opening created by the first paper partially wrapping the filter lengths can have variable dimensions in function of the specific needing.

Said filling material can be variously granular, having a filtering and/or aromatizing activity and/or having a different activity.

The present invention will be now described, for illustrative but not limitative purposes, according to its preferred embodiments, with particular reference to the figures of the enclosed drawings, wherein: figure 1 is a perspective view of a series of filtering lengths according to the invention, opened to show their inner features; figure 2 is a cross section view along the line ll-ll of figure 1 ; figure 3 is a cross section view along the line Ill-Ill of figure 1 ; and figure 4 is a longitudinal section view of the filter series of figure

1.

Referring now to all the figures of the enclosed drawings, and particularly, at the beginning, at figure 1 , it is shown a rod 1 comprising six multiple cavity filters according to the invention, wherein between the lines A-A and B-B a single filter 2 is individuated as it will be obtained after the cut of the rod 1.

Rod 1 comprising the filters 2 provides a plurality of filter lengths 3, made up of cellulose acetate or of any other suitable material, spaced each other to obtain a cavity 4, for the following filling by the chosen material. Around the spaced lengths 3 a first paper 6 is provided, enclosing the lengths 3 in such a way to leave an upper opening to feed the material 5 up to a height well above the half of the circumference of lengths 3 (see particularly figure 4).

A further outer containment paper 7 is provided externally with respect to the paper 6, said paper 7 being completely closed only after the filling of the cavities 4 by material 5. Along the manufacturing line, it will be sufficient to provide the application of inner paper 6, within paper 7, on which the lengths 3 will be placed, and to completely close said paper 6 about the same lengths 3 in such a way to partially wrap their circumference. The simple adding of the paper 6, that, when it is completely wrapped, must partially surround lengths 3, thus allow to obtain a very high filling of the cavity 4 without requiring substantial modifications and high costs for the manufacturing line.

As already said, the solution suggested according to the present invention is valid independently from the materials employed for lengths 3, papers 6 and 7, the filling material 5, as well as the number of cavities provided in a single filter 2 (in other words, notwithstanding the basic solution provides an assembly comprising length 3 - cavity 4 - length 3, it is also possible to realise filters having a structure of the kind length 3 - cavity 4 - length 3 - cavity 4 - length 3, etc.)

Furthermore, it must be pointed out that the two papers 6 and 7 could be comprised of the same material or of different materials having different features in function of the specific needing.

The present invention has been described for illustrative but not limitative purposes, according to its preferred embodiments, but it is to be understood that modifications and/or changes can be introduced by those skilled in the art without departing from the relevant scope as defined in the enclosed claims.

Claims

1. Multiple cavity filter characterised in that it comprises at least a first filter length and a second filter length, at least a cavity between said first and second filter lengths, a first paper, partially externally enclosing said first and second filter lengths, as well as said cavity, leaving an upper filling opening, filling material to be introduced within said cavity through said opening created by said first paper, and a second paper, outer with respect to said first paper, completely wrapping said first inner paper and said first and second filter lengths, and said cavity.

2. Multiple cavity filter according to claim 1 , characterised in that said at least first and second filter lengths are comprised of cellulose acetate and/or pure cellulose or other suitable materials.

3. Multiple cavity filter according to claim 1 or 2, characterised in that said first and second wrapping papers are comprised of the same material or of different materials.

4. Multiple cavity filter according to claim 1 or 2, characterised in that said first and second wrapping papers are comprised of different materials.

5. Multiple cavity filter according to one of the preceding claims, characterised in that said filter provides a plurality of cavities between a plurality of filter lengths.

6. Multiple cavity filter according to one of the preceding claims, characterised in that said opening created by the first paper partially wrapping the filter lengths has variable dimensions in function of the specific needing.

7. Multiple cavity filter according to one of the preceding claims, characterised in that said filling material is variously granular, having a filtering and/or aromatizing activity and/or having a different activity.

8. Multiple cavity filter according to each one of the preceding claims, substantially as illustrated and described.