Patent Description:
Extractor hoods have been known for some time, which can be placed above hobs and are provided with a filter for the grease, the filter conventionally being defined by a metal body with slots which can retain the grease aspirated by the hood with vapours (or fumes) which are generated on the hob during the preparation of food. These hoods comprise a structure containing a fan which can aspirate said vapours through an opening of the hood which is placed above the hob. On said opening there is conventionally placed a filtering unit which can retain the grease associated with these vapours, said filtering unit comprising said filter for the grease.

The filter can be placed directly at this opening, or it can be associated with one or more frames of the filter, according to the width of the hood (for example a hood with a width of <NUM>, <NUM>, <NUM>, etc.) with slots which can permit the passage of the vapour towards the filter, the filter being further to the inside of the structure of the hood than the frame(s).

A problem with the filters for the grease of the extractor hoods, in particular those filters which are made of metal, is that this grease condenses on the filter, and can drip onto the hob below, with obvious consequences of a hygienic and aesthetic nature.

<CIT> faces the problem of dripping of the condensed grease onto the hob. This prior text describes a hob comprising an aspiration region (the opening of the structure of the hood), where there are placed at least two adjacent filters for the grease which are supported by a container for the filters. At least two adjacent (flat) filtering screens are placed at the filters for the grease, and are further to the outside of the aspiration region than these filters. In other words, the filters for the grease are further to the inside of the corresponding screens than the structure of the hood.

Between the filters there is present a space or distance placed corresponding to a similar space for aspiration of the vapour, which space is present between the filtering screens, the aspiration space between these screens being smaller than the distance which is present between the filters, such that the screens cover the active filtering surfaces of said filters.

The filters are placed at a distance from the screens, and between them there is thus present a passage which can receive the vapour aspirated, and give rise to a centrifugal effect thereon, such as to assist the aspiration and filtering thereof.

Between each pair of filters, above the space for aspiration of the vapour of the filtering screens, there is placed an element for collection and guiding of the condensate which collects the condensate of the vapour aspirated, and makes the condensate fall onto the filtering screens. This element for collection and guiding of the condensate comprises at least one dripping edge which is placed at a distance above a corresponding filtering screen; said element has an inclined or rounded form along which the condensate runs as far as each dripping edge. Preferably this element has the form of an isosceles or even scalene triangle.

However, the known solution collects the condensate inside the passage between each filtering screen and the corresponding filter for the grease, said condensate thus accumulating on the surface of this screen and limiting the dimension of the passage in which the aspirated vapour moves. Furthermore, the condensate is always affected by this aspirated vapour, and, because of the temperature of the vapour, it can dissolve once more (or not condense completely), and can exit from the aspiration space which is present between the adjacent filtering screens, transported by the vapour aspirated.

<CIT> discloses a grease filter comprising a repeating series of individual convoluted first baffle walls and a repeating series of individual convoluted second baffle walls.

<CIT> discloses a separator filter and a flame protection filter. Both filters have an outer metal frame which is filled with metal wool and a plurality of individual metal profile rails, respectively, which rails are arranged in the metal frame in two planes parallel and at respective distances from one another.

<CIT> discloses an extractor hood with at least one grease filter, the filter body of which consists of several layers of expanded aluminium metal or nonwoven.

<CIT> discloses a reusable grease filter having a plurality of individual louvers held in place by a surrounding frame.

<CIT> discloses a range hood with a double absorption filter, which filter is formed by a parallel integration of a plurality of longitudinal hollow bodies each made of thick paper.

The objective of the present invention is to provide an extractor hood for hobs with a filter for the grease, which hood operates efficiently and in a manner which is improved compared with the prior art in retaining the condensate of the vapours aspirated, and in particular of the grease present therein, while being of simple and thus inexpensive design.

Another objective of the invention is to provide a hood of the aforementioned type which permits recuperation of said condensate of the vapours from the hood.

A further objective is to provide a hood of the aforementioned type which makes possible optimal filtering performance.

Another objective is to provide an extractor hood of the aforementioned type which is simple to produce.

These objectives and others, which will become apparent to persons skilled in the art, are achieved by an extractor hood according to the appended claims.

For better understanding of the present invention, and purely by way of non-limiting example, the following drawings are appended, in which:.

With reference to the aforementioned <FIG>, an extractor hood is generally indicated as <NUM>, and comprises a structure <NUM> containing a fan <NUM> which can aspirate through an opening of the hood <NUM> vapours which are generated by food being prepared on a hob above which the hood <NUM> is placed. The substance aspirated is filtered by a filtering unit <NUM> placed at the opening of the hood <NUM>, and is discharged outside the hood <NUM> from an outlet of the hood <NUM>. In a known manner, the vapours aspirated and filtered can be readmitted into the environment where the hob is located, or they can be ejected outside said environment.

The filtering unit <NUM> is placed in the structure <NUM>, and is supported in any known manner therein, such as to be able to be removed from the opening <NUM> in order for it to be cleaned. This filtering unit <NUM> comprises a filter <NUM> for the grease, which is generally made of metal plate (stainless steel or aluminium alloy), associated with a frame <NUM> of the filter. This frame has a plurality of slots <NUM> through which the vapours emitted by the food being prepared can be aspirated by the fan <NUM>. The width of the slots <NUM> can be between <NUM> and <NUM>, advantageously between <NUM> and <NUM>.

These vapours contain water, grease, and possibly small particles which are released from the food and are filtered by the filter <NUM> for the grease before reaching the fan <NUM> and being ejected from the hood <NUM>.

The filter <NUM> for the grease is further to the inside of the structure of the hood <NUM> than the frame <NUM> of the filter is.

The filter is thus placed on the outside of the opening <NUM> (see <FIG> and <FIG>, for example).

The filter <NUM> for the grease comprises a body <NUM> of the folded or pleated type, and has a plurality of filtering elements <NUM> with a triangular cross-section (without a base) and in the form of an inverted "V" relative to the frame <NUM> of the filter, which elements are connected to one another at the ends <NUM> of their adjacent lateral portions or inclined sides <NUM>, said body being in a single piece (as in the figures). In a comparative example not part of the invention, said body could be defined by a plurality of modular elements brought towards one another and in contact with one another by means of the ends <NUM> of the inclined sides <NUM> of their end lateral filtering elements <NUM>. As an alternative to the triangular cross-section in the form of an inverted "V", the filtering elements <NUM> can have a form with a curved profile, but are connected to one another by means of the adjacent ends <NUM> of their lateral portions <NUM>, which in this case are curved.

In the case of elements <NUM> in the form of an inverted "V", each of them has an angle at the base (α or β) formed with the frame <NUM> which is preferably between <NUM>° and <NUM>°, and is advantageously <NUM>°, and a height h which is preferably between <NUM> and <NUM>, and is advantageously between <NUM> or <NUM> (see <FIG>).

These filtering elements <NUM> are in contact with the frame <NUM> of the filter, and are supported by their ends <NUM> on this frame at areas <NUM> thereof which are present between the slots <NUM>. By this means, a vertex part <NUM>, or part for joining of the sides <NUM> (i.e. the part <NUM> of each filtering element <NUM> which is further from the frame <NUM> of the filter) is placed within a corresponding slot <NUM>.

Within each side <NUM> of the filtering elements <NUM> there are present passages <NUM> for the vapours (shown only partly on the sides <NUM> of the filter), which passages penetrate into the filtering unit <NUM> via the corresponding slot <NUM> of the frame <NUM> of the filter <NUM>. These passages <NUM> comprise an opening <NUM> superimposed at a distance by a cover <NUM> which is integral with said side <NUM>, and is obtained therefrom by mechanical deformation of the side itself.

As previously stated, the vapours pass through the slot <NUM> and reach the passages <NUM> of the filter <NUM>. They then penetrate inside the openings <NUM>, but come into contact with the corresponding covers <NUM>. When they meet the covers, they are deflected onto an internal surface 18A of the side <NUM> (internal relative to the structure <NUM>, i.e. facing towards the fan <NUM>), and condense, falling towards the frame <NUM> of the filter (see the arrows F in <FIG>), i.e. they fall onto a collection or "downstream" position <NUM> of the filter <NUM> for the grease, where they converge and join together or come into contact with the ends <NUM> of two adjacent filtering elements <NUM>. It will be appreciated that, in the case of filtering elements of terminal lateral ends of the filter <NUM> for the grease, the condensed vapours fall directly onto an inner side 11A of the frame <NUM> of the filter.

It should be noted that the filtering unit <NUM> (and thus the filter <NUM> for the grease and the frame <NUM> of the filter) is arranged inclined at the opening <NUM>. This is obtained for example thanks to the triangular lateral supports <NUM> of said frame <NUM>, which are supported on a perimeter frame <NUM> of the hood <NUM>, delimiting the opening <NUM>.

It will be appreciated that other means can be provided for maintaining the filtering unit <NUM> inclined relative to a plane of the opening <NUM>. The inclination faces towards the rear part <NUM> of the hood <NUM>, which is distant from the front side <NUM> close to a user who approaches the hub below (not shown).

The inclination of the filtering unit <NUM> relative to a plane of the unit <NUM> can be between <NUM>° and <NUM>°, and preferably between <NUM>° and <NUM>°.

Thanks to the inclination of the filtering unit <NUM>, the condensate thereon is collected by a collection element <NUM> placed in the vicinity of the rear part <NUM> of the hood, from where it can be removed. The removal can take place by removing the condensate collection element <NUM>. An alternative for the elimination of the water which is present in the collection unit can be constituted by a hole <NUM> provided in the lowest area of the collection element <NUM>, which hole is normally closed, and is opened by the user by means of a conventional mechanism which permits the discharge thereof.

Thanks to the form of an inverted "V" of the filtering element <NUM>, the flow of the condensed vapours (or "condensate") is facilitated towards the collection areas (downstream portions <NUM> of the filter <NUM> or inner side 11A of the frame <NUM>), which condensate then descends towards the rear part <NUM> of the hood. The passages <NUM> (in the form of "blind slats" or "louvres") have a geometry and arrangement such that the drops of condensate which form on the inner surfaces 18A of the sides <NUM> of the filtering elements <NUM> do not fall onto the hub below through the slots <NUM> of the frame of the filter.

The suction pressure created by the aspiration of the hood facilitates the removal of the drops of condensate which form on the surfaces 18A, simultaneously removing them from the openings <NUM> of the passages <NUM> of the filtering element <NUM>.

It will be appreciated that the passages <NUM> can also be produced with forms and/or embodiments which are different from those described in relation with the figures, which represent only a non-limiting embodiment of the invention.

<FIG> show two variants of the invention. In these figures, parts which correspond to, or are identical to, those already described in relation with <FIG> are indicated with the same numerical references.

According to the two variants (<FIG> and <FIG>), between the filter <NUM> for the grease and the frame <NUM> of the filter a further, drawn (flat) filtering layer <NUM> is present, supported on the inner side 11A of the frame <NUM>. It will be appreciated that this further filtering layer <NUM> is also provided with passages <NUM> similar to those <NUM> of the filtering element <NUM> of the filter <NUM> for the grease, i.e. the passages each have an opening <NUM> and a corresponding cover <NUM> which is placed at a distance from the opening, and is integral with the filtering layer <NUM>.

In the variants in <FIG> and <FIG>, the flat filtering layer has the passages <NUM> also at the areas <NUM> of the frame <NUM> of the filter, whereas in the variant in <FIG> and <FIG>, these passages <NUM> are not provided at said areas <NUM>.

In given conditions of aspiration or speed of passage of the air aspirated, these variants produce a type of controlled condensation on the filter <NUM>, thus contributing towards reducing the excess condensate which can form in the metal areas of the frame <NUM> of the filter.

The figures show filters <NUM> for the grease with filtering elements which have passages <NUM> for the vapour with a particular configuration. As previously stated, the passages can also have different forms, such as the one shown in <FIG>, with the form of a rhombus or polygon. This is a possible variant of the passages <NUM> which are present on the filter <NUM>, produced by drawing the metal plate which defines the filter, without drawing machining, which is also more economical. This version is also represented in <FIG>, which show at least one further metal filtering layer <NUM> (in the figures there are two of them, superimposed) added on top of the pleated filter <NUM>. These filtering layers <NUM> placed above the filter <NUM> serve the purpose of retaining the particles of grease and oil more efficiently.

In addition, the thickness of the filter <NUM>, the material from which it is obtained, and the geometry and dimensions of the openings <NUM> of the passages <NUM>, can be different.

For example, with reference to <FIG>, the thickness S can be between <NUM> and <NUM>, and advantageously between <NUM> and <NUM>. The width D of the openings <NUM> can be between <NUM> and <NUM>, preferably between <NUM> and <NUM>, and advantageously between <NUM> and <NUM>. The other dimension D1 of the rhombus of the openings <NUM> can be between <NUM> and <NUM>, and preferably between <NUM> and <NUM>.

The materials used can be stainless steel, or metal alloys, preferably aluminium alloys.

Finally, the filter <NUM> for the grease can be coated with a non-absorbent or absorbent coating such as to improve the effect of non-dripping through the slots <NUM> of the frame <NUM> for the filter. It should be understood that the filter can also be used to filter in general vapours and fumes which generate on a hob during the preparation of food. These treatments also serve the purpose of modifying the adhesion capacity of the surfaces of the filtering layers <NUM> and <NUM> and of the filter <NUM>, and of facilitating the removal of dirt which accumulates therein during cooking, and advantageously have an antibacterial effect in the case of the absorbent treatment.

Claim 1:
Extractor hood (<NUM>) for a hob which can aspirate vapours or fumes generated during the preparation of food on said hob, the hood (<NUM>) comprising a structure (<NUM>) containing a fan (<NUM>) for the aspiration of said vapours or fumes through an opening (<NUM>) of the hood (<NUM>), at said opening (<NUM>) there being provided a filtering unit (<NUM>) comprising at least one metal filter, namely a filter (<NUM>) for the grease, associated with a frame (<NUM>) of the filter which has slots (<NUM>) for the passage of said vapours or fumes towards the metal filter (<NUM>), said slots (<NUM>) being separated by flat areas (<NUM>), said filtering unit (<NUM>) being supported by said structure (<NUM>) of the hood, said metal filter being further to the inside of said structure than the frame (<NUM>) of the filter, wherein said filtering unit (<NUM>) is inclined relative to the opening of the hood (<NUM>) where it is positioned, the metal filter (<NUM>) being pleated and being supported on said frame for the filter, said metal filter (<NUM>) having a plurality of adjacent filtering elements (<NUM>) which are distant from said frame (<NUM>) for the filter, with a vertex part (<NUM>), and are connected to one another at ends (<NUM>) of their lateral portions (<NUM>) which are at least close to said frame (<NUM>) for the filter, said lateral portions (<NUM>) having a plurality of distributed passages (<NUM>) which can deflect the vapours or fumes aspirated onto a surface (18A) of said lateral portions (<NUM>) inside the hood (<NUM>) where said vapours or fumes condense, the condensate then being collected inside the hood (<NUM>) such as to prevent dripping onto the hob, wherein the filter (<NUM>) for the grease comprises a body (<NUM>) of the pleated type, which body has said plurality of filtering elements (<NUM>), said body (<NUM>) being in a single piece.