The present invention relates to a nasal cavity filter and to a filter assembly.

More specifically, the invention concerns a filter of the above kind, particularly studied and realised to block impurities present in the air and entering within human nasal cavities, and a filter assembly comprising at least two filters coupled each other.

The specification will be, in the following, addressed to the structure of a filter for purifying air entering within nasal cavities , but it is well evident that the same must not be considered limited to said specific use .

Devices are known suitable to purify air entering within nasal cavities, said devices having a structure as described in the patent application WO 2008/139499, wherein a filter having a cylindrical shape, particularly a frusto-conical shape, is disclosed, comprising four fins suitable to create turbulences in air entering there through. Inner surface of filter and fin surface are covered by a gelatinous substance withholding impurities present in the entering air.

However, a drawback of known filter is represented by shape of outer surface subjecting nasal cavities to a high mechanical stress.

A further drawback of known solution is represented by the shape of fins not permitting an efficient exchange with entering air.

In view of the above, it is therefore object of the present invention that of realising a filter overcoming drawbacks of known solutions.

Particularly, an object of the invention is that of realising a filter with an outer surface having a geometry suitable to ensure a yielding permitting to easily conform to the nasal cavity of a human being, thus reducing mechanical stress due to contact between filter and nasal cavity. Further object of the present invention is that of realising a filter having an inner surface increasing turbulences in entering air to promote withholding of almost all impurities contained therein.

These and other results are obtained according to the invention by a nasal cavity filter comprising a helicoidal element within the inner cavity and a gelatinous substance covering the whole inner surface of the filter.

It is therefore specific object of the present invention a nasal cavity filter comprising

- a substantially cylindrical support wall, an outer surface of said support wall being suitable to adhere to the nasal cavity walls, and an inner surface of said support wall being suitable to define a cavity for passage of air from inside to outside, and vice versa; and

- a layer comprised of a gelatinous substance suitable to cover said inner surface;

said filter being characterized in that said inner surface of said wall comprises at least an element, said element preferably having a helicoidal shape, suitable to generate turbulences through air flow passing through said cavity.

Preferably, according to the invention, said helicoidal shape element is integral with said inner surface of said wall, or it is coupled with said inner surface of said wall.

Still according to the invention, said outer surface of said wall comprises projecting circular rings.

Furthermore, according to the invention, said filter is comprised of 20 shorts medical PVC material.

In a particularly preferred embodiment of the filter according to the invention, said gelling substance comprises a reticulated dextran polymer and a gelling polymer, particularly said reticulated dextran comprises glucose molecules bond by a glycosidic bond. Always according to the invention, said gelatinous substance is an aqueous anionic gel based on a cross- bond dextran polysaccharide, wherein glucose molecules are linearly bond each other with glycosidic bond al- >6, while cross bonding is due to glycosidic bonds al- >4 (sometimes also al->2 and al->3) and wherein functional group R, diethyl-2 -hydroxipropilamminoethil (a quaternary ammine) makes it behaving as a string exchanger within a wide pH range.

Always according to the invention, said wall has a frusto-conical shape.

The invention further relates to a filter assembly comprising a first nasal cavity filter and a second nasal cavity filter, each one of said filters being as described in the above, and a coupling element suitable to couple said first and said second filters.

The present invention will be now described or illustrative but not limitative purposes according to its preferred embodiments, with particular reference to the figures of the enclosed drawings, wherein:

figure 1 shows a front perspective view of nasal filter cavity;

figure 2 shows a lateral view of helicoidal element; figure 3 shows a front perspective view of a preferred embodiment of filter of figure 1;

figure 4 shows a lateral section view of the filter of figure 1 coupled with another filter in a filter assembly;

figure 5 shows a lateral view of assembly of figure 4; and

figure 6 shows a top view of assembly of figure 4.

The same reference will be used in the different view to indicate similar parts.

Making reference to figure 1, it is described a filter 1 suitable to be inserted within a nasal cavity.

Said filter 1 comprises a cylindrically shaped support wall 2, particularly having a frusto-conical shape. Said wall 2 comprises an outer surface 3 and an inner surface 4 within which air can slide from inside toward outside and vice versa.

As shown in figures 1 and 2, said filter 1 further comprises a helicoidal element 5, suitable to be inserted within said inner surface 5 of said wall 2. Said helicoidal element 5 can be realised integral with said inner surface 4.

As an alternative, said helicoidal element 5 can be integrally coupled with said inner surface 4.

Said helicoidal element 5 is suitable to create turbulences within air flow flowing within the cavity generated by inner surface 4 of said wall 2.

Said inner surface 4 and said helicoidal element 5 are covered by a gelatinous substance or gel, not shown in the figures.

Said substance comprises a crossbond dextran polymer and a jellifying polymer.

Particularly, said crossbond dextran polymer comprises glucose molecules linearly bond each other by a glycosidic bond.

Said substance is suitable to absorb impurities present in air flow entering within the cavity denied by said inner surface 4, particularly about 82% of polluting particles having a diameter between 0 and 10 Dm.

Turbulences generated by helicoidal element 5 create a high kinetic force on said polluting particles, that are so captured by gel substance .

All surface of said helicoidal element 5 is covered by gel substance. The above permits air filtering also when exiting from nasal cavities thus making filter suitable to be used also in health field.

In an embodiment, as shown in figure 3, said outer surface 3 of said wall 2 can comprise a plurality of concentric projecting circular rings 3', 3" and 3"', reducing stress on inner mucous of nasal cavities, thus promoting stability of filter 1 within the same nasal cavity.

All the structure of filter 1 can be comprised of PVC of medical grade such as TPE translucent or transparent unloaded compound having high performances and low deformation index with respect to original shape, also known as compression set. Said material is substantially comprised of saturated block styrene copolymers suitable for injection molding, also known as 20 shore PVC, i.e. a biocompatible material.

As shown in figures 4 and 5, said filter 1 can be coupled with another filter 6 by a coupling element 7. Said filter 6 has the same structure described for filter 1.

Said coupling element 7 is a not rigid bridge easing introduction and removal of filters 1 and 6 within two cavities of a human nose.

Configuration of filter 1 according to the invention, i.e. combination of its height, angle, thickness, helicoidal pitch, is such to work only within a specific range of "air flow", between 12 and 332 litres per minute, substantially corresponding to breathing: breathing of a child of breathing of an adult making a short run (3.2 km/h) with an average physical efficiency.

Further, geometry of filter 1 is such to create a precise turbulence of air flow. Particulate material (PM) with large dimensions (PM 10) hits lower part of device, where helicoids base is provided; smaller PM (PM 2.5 or less, up to sub micron PM of 0.09 or less), even entering within the helicoids, is violently thrown on filter cavity, and captured by bio gel by viscosity action; remaining substances not touching filter 1 wall or helicoids, always providing gel on its surface, is attracted by electrostaticity of the same gel. By this solution, capture of PM up to 82% and prevention of loss of pressure while breathing are obtained.

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