EP2839220B1

EP2839220B1 - Range hood comprising an odour filter

Info

Publication number: EP2839220B1
Application number: EP13727977.4A
Authority: EP
Inventors: Mauro SANTUCCI; Cristina VIOZZI
Original assignee: Whirlpool EMEA SpA
Current assignee: Whirlpool EMEA SpA
Priority date: 2012-04-17
Filing date: 2013-04-09
Publication date: 2021-02-24
Anticipated expiration: 2033-04-09
Also published as: ITTO20120332A1; EP2839220A1; EA201491884A1; EA028025B1; WO2013156897A1

Description

[TECHNICAL FIELD]

The present invention relates to the field of extraction or recirculating hoods, in particular for treating fumes and odours in household environments, e.g. a range hood.

[PRIOR ART]

Aspirating and/or filtering devices are known which are to be installed near places where fumes or odours are generated. For example, such aspirating and/or filtering devices are called "hoods" and are typically installed in household environments, such as a kitchen.
Within the context of the present invention, the term "fumes" designates an aeriform substance, typically air, contaminated by suspended liquid, solid or ethereal particles. As far as range hoods are concerned, the aspirated fumes typically transport suspended greasy particles and odours generated by food being cooked.
Some hoods take in fumes from the environment, discharging the aspirated air into a ventilation duct, which then evacuates both fumes and odours out in the open; such hoods are hence referred to as "extraction hoods".
Some other hoods collect fumes from the environment, filter them, and then reintroduce purified air into the same environment; hoods of this latter type are called "recirculating hoods", and the present invention proves to be especially advantageous for such recirculating hoods.
One example of a hood and an associated filter is known from document DE202009017271U1 , which describes a filter element comprising multiple filtering layers arranged in series, which include odour filtering layers comprising activated carbon.
The hood filters known in the art, however, suffer from the drawback that they cannot fully exploit their filter elements. In fact, activated carbon has a tendency to lose its adsorbing capacity after a certain number of working hours, so that the effectiveness of the filter will progressively decrease Further prior art can be found in the documents DE 198 38 648 A1 and DE 10 2009 023241 A1 .

[OBJECTS AND SUMMARY OF THE INVENTION]

It is the object of the present invention to overcome some of the problems of the prior art.
In particular, it is the object of the present invention to provide a hood comprising a fume collector, in fluidic connection with a chimney, and air circulating means for drawing air through said fume collector and directing it into said chimney and further comprising an odour filter adapted to filter said air.
A further object of the present invention is to provide a hood filter comprising at least two consecutive filtering layers along the direction of flow; the filter has a substantially cylindrical shape, thus defining a lateral filtering surface, wherein the two filtering layers are concentrically arranged on the lateral surface, being placed one inside the other.
In this manner, the filter has a larger filtering surface, the occupied volume being equal, and allows for a better exploitation of the filter elements. These advantages beneficially reflect in the performance of the hood fitted with such a filter in terms of filter efficiency and utilization.
According to the invention, the first filtering layer comprises a pleated textile, and the second filtering layer comprises activated carbon.
Preferably, the filter comprises at least one air flow inlet on a base of the filter, in a position substantially transversal to the lateral filtering surface. This allows to create a compact filter particularly suitable for use in household filtering hoods.
In the filter, the first pleated-textile filtering layer is preferably internal with respect to the second activated-carbon filtering layer, thus being located upstream along the direction of flow. The air flow to be filtered is thus first filtered by the textile and only afterwards by the activated carbon; this improves the filtering effectiveness in terms of odour elimination, while also improving the life of the active elements, such as activated carbon.
Preferably, the pleated-textile filtering layer also comprises activated carbon. In addition, the second filtering layer (402) preferably comprises activated carbon in granular form. This ensures higher effectiveness in terms of odour filtration.
An object, not being part of the invention, provides a filter-housing assembly for use in a hood, i.e. an special element adapted to house the filter of the present invention, which contributes, in synergy with the latter, to the creation of an improved filtering system, in particular suitable for use in a filtering hood. The assembly comprises a filter according to the present invention, and further comprises a housing adapted to receive the filter; the housing comprises at least one bottom aperture that provides a fluidic connection between the hood and the filter, and further comprises at least one aperture for the outflow of filtered air from the filter.
The housing also makes maintenance of the hood simpler, in that it is easier to service and/or replace a filter in the assembly.
Preferably, the housing has a substantially box-like shape for containing the filter, and the outflow aperture is located on at least one of the side faces of the housing. This allows to minimize the overall dimensions of the filter-housing assembly.
Preferably, the housing is made of stainless steel, or any other material suitable for domestic use, which is easy to clean and resistant to agents present in the environment, such as grease and dust.
Preferably, the shape of the filter is adapted to be coupled, in the assembly, to the bottom aperture of the housing, thereby creating a fluidic connection for an air flow within the filter itself. This further improves the compactness of the assembly.
Further objects and advantages of the present invention will become more apparent from the following detailed description and from the annexed drawings.

[BRIEF DESCRIPTION OF THE DRAWINGS]

Some preferred and advantageous embodiments will now be described by way of non-limiting example with reference to the annexed drawings, wherein:

Figure 1 shows an example of embodiment of a hood comprising a filter according to the present invention.
Figure 2 is a sectional view of the hood of Figure 1.
Figure 3 shows in detail a filter housing of the hood of Figure 1.
Figure 4 shows a cross-section of the housing of Figure 3, inside of which a filter according to the present invention is visible.
Figure 5 is a perspective view of a filter according to the present invention.
Figure 6 is a perspective transparency view of a filter according to the present invention.

The drawings show different aspects and embodiments of the present invention and, where appropriate, similar structures, components, materials and/or elements in the various drawings are designated by the same reference numerals.

[DETAILED DESCRIPTION OF THE INVENTION]

Figure 1 shows one example of a range hood 101 of the recirculating type. The hood 101 comprises a fume collector 102, which is typically positioned above a cooking top; the fume collector 102 may comprise further filter elements (not shown) for filtering airborne greasy particles, consisting of filters in accordance with the teachings of the prior art.
The hood 101 further comprises air circulating means (not shown), e.g. a fan, adapted to draw air from the fume collector 102 and convey it through the chimney 104. At the top end of the hood 101 there is a housing 106 for a filter, in particular for an odour filter. The housing 106 comprises a plurality of apertures to allow the air drawn by the hood to flow out into the household environment after having been appropriately filtered. In this way it is possible to purify the air collected by the hood 101 from any ethereal substances transporting unpleasant odours. In the preferred embodiment, the housing 106 has a substantially cubic shape, apertures being provided on the three side faces that look on to the environment. In an alternative embodiment, which is particularly suited for "island-type" hoods, i.e. installed far from the room walls, the housing may comprise aperture on all four side faces.
The apertures of the housing 106 have a reduced section compared to the lateral surface of the housing 106, preferably less than 10% of the total lateral area. In this manner, it is possible to create a hood in which there is a load loss concentrated downstream of the odour filter, thereby improving the filtering action of the latter thanks to an appropriate reduction of the air flow velocity.
The housing 106 also performs an aesthetical function, since it hides the filter from view to any users in the room where the hood 101 is located. In fact, it should be reminded that the hood 101 is of the "recirculating" type, and the air collected by the fume collector 102, once purified, is reintroduced into the same environment; therefore, it is typically visible to the user. The housing 106 is preferably made of a metallic material, such as stainless steel, in particular suitable for use in household conditions, with an aesthetically pleasant surface finish.
Figure 2 shows a sectional side view of the hood 101, where the air circulating means 103 are visible, which deliver the air from the chimney 104 into the duct 107 (between which the air circulating means, e.g. a fan, are interposed), which duct is in fluidic connection with the filter 105, which will be described more in detail below.
Figure 3 shows in more detail the housing 106, separated from the hood 101. In particular, one can appreciate that there is a bottom aperture 301 on the base of the housing 106, through which the air to be filtered, coming from the duct 107, enters the filter. One can also more clearly appreciate the configuration of the lateral surfaces 302 of the housing, which create the small-section apertures described above. Preferably, at least one of the lateral surfaces 302 comprises removable mounting means, so that it can be removed by a user or an operator for servicing the filter housed within.
In particular, the housing comprises a frame adapted to structurally support a plurality of panels constrained to the frame itself and arranged on the faces of the housing in such a way as to create a structure within which the filter is accommodated.
In addition, the panels have such dimensions as to form an interspace between each panel and the frame, thus creating a plurality of apertures for the outflow of the filtered air. Figure 4 is a sectional view along a horizontal plane of the housing 106, which shows a cross-section of the filter 105 housed therein.
The filter 105 comprises a substantially cylindrical structure, which is internally hollow and which matches the aperture 301 so as to allow the air that must be filtered to enter the filter 105. The side walls of the filter 105 are permeable to air and comprise filtering materials as will be described below, so that they can filter the air, e.g. to reduce the odours thereof.
The filter 105 creates a double concentric filter structure, comprising an internal filtering portion 401 comprising a pleated filtering textile, and an external filtering portion 402 comprising activated carbon.
Preferably, the internal filtering portion 401 comprises a pleated textile with pleats substantially longitudinal relative to the filter.
Preferably, the external filtering portion 402 comprises a structure made of perforated microstretched sheet-metal or a reticular structure, which is adapted to create a containment volume for the activated carbon. Preferably, the activated carbon is in granular form, preferably with such characteristics as to have a CCl4 Index ≥80% (calculated with the ASTM3467-89 method) and a surface area >1100 Mq/g (calculated with the BET with Nitrogen method).
Preferably, the pleated textile has a number of pleats between 50 and 100, preferably between 60 and 75, more preferably between 65 and 70.
In a preferred embodiment, the internal aperture of the filter 105 has a diameter of 160 mm to 180 mm. In a preferred embodiment, the internal filtering portion 401 made of pleated textile has a thickness of 35 mm to 50 mm. Preferably, the external filtering portion 402 comprising activated carbon has a thickness of 10 mm to 20 mm.
Preferably, the filter 105 has a total diameter of 280 mm to 320 mm and a height of 270 mm to 300 mm.
Figure 5 shows a general view of the filter 105. The structure of the filter 105 is such that it defines an inlet 501 on the bottom face of the filter 105, which inlet is arranged transversally with respect to the structure with cylindrical symmetry. The inlet 501 is adapted to be coupled to the aperture 301 of the housing 106, so as to allow air to flow through the filter 105 without any leakage. For example, the interface between the aperture 301 and the inlet 501 features a suitable shape coupling. Advantageously, the diameter of the inlet 501 is greater than the diameter of the aperture 301, so as to appropriately slow down the flow immediately upstream of the filtering layers. The top face 502 of the filter 105 is preferably closed, for example, by a plate of a material such as steel. In this manner, air filtering only occurs through the lateral surface 503 of the filter 105. In an alternative embodiment, the top face of the filter 502 may be open, and it may be closed by coupling it to an additional surface of the housing 106. For example, the plate on the top face of the housing 106 may abut on the top face 502 of the filter 105, and a sealing gasket may additionally be used.
Figure 6 shows a transparency view of the filter 105, where one can appreciate the concentric arrangement of the filter elements 401 and 402 of the filter 105. This concentric arrangement maximizes the filtering surface, the outer dimensions being equal, and makes it possible to create a more efficient and compact filter, wherein the activated-carbon filter elements have an extended life. Furthermore, the provision of a lateral filtering surface in the filter 105, when inserted in a hood 101, allows diverting the filtered air flow from the direction of the chimney 104. This improves the fluid-dynamics within the filter 105, resulting in better suction and filtering actions. It is also possible to effectively divert the flow inside the housing 106 to reduce the operating noise of the hood 101 and to prevent the filtered air from directly hitting the walls near the hood 101, e.g. the rear wall or the ceiling. This saves the walls of the household environment from undergoing any fouling.
It is evident that the "substantially cylindrical" shape refers to a solid whose projection onto a plane perpendicular to the axis of symmetry is a closed figure, such as, for example, a circumference or an ellipse. For example, it is understood that a truncated cone or a solid created on an elliptical base or the like should be considered to have a "substantially cylindrical" shape.
It is apparent that the present invention, although it has been described herein with reference to a preferred application thereof to recirculating hoods, may likewise be used in combination with extraction hoods, in particular should this be required by specific environmental regulations.

Claims

A hood (101) comprising a fume collector (102), in fluidic connection with a chimney (104), and air circulating means (103) for drawing air through said fume collector (102) and directing it into said chimney (104) and further comprising an odour filter (105) adapted to filter said air,
characterised in that said odour filter (105) comprises at least two filtering layers (401, 402) arranged consecutively along the direction of flow,
wherein said odour filter (105) has a substantially cylindrical shape, thus defining a lateral filtering surface (503), and said filtering layers (401, 402) are arranged concentrically on said lateral surface (503), being placed one inside the other,
wherein a first filtering layer (401) comprises a pleated textile and a second filtering layer (402) comprises activated carbon,
said odour filter (105) further comprising at least one inlet (501) for an air flow, said inlet (501) being substantially transversal to said lateral filtering surface (503) on a base of said odour filter (105).
Hood (101) according to claim 1, wherein said first filtering layer (401) is internal with respect to said second filtering layer (402) in said odour filter (105), thus being located upstream of said second filtering layer (402) along said direction of flow.