Device for silencing extractor hoods and the like

Abstract: A device for silencing extractor hoods and the like comprising a silencing element (3) made of sound-deadening material which is suitable to be associated with a respective intake of the extractor element (2) arranged inside the body (10) of the hood and meant to collect the fumes. The silencing element (3) is shaped like a cap and is provided with an intake which is directed downward in the assembly position.

Description: The present invention relates to a device for silencing extractor (ventilation) hoods and the like. It is known to use extractor hoods designed to eliminate fumes and vapors produced by cookers and the like by conveying such vapors externally through a suitable vent pipe. Extractor hoods generally have a pyramid-shaped body which is meant to collect the fumes and has, in its upper region, an outlet hole which is suitable for connection to a suitable vent pipe. An extractor element, usually constituted by a centrifugal fan, is accommodated inside the pyramid-shaped body of the hood. Commonly used centrifugal fans are rather noisy, and the noise is generated mainly at the intakes of the fans. The noise generated by the fans is an evident factor in the noise pollution of the rooms in which extractor hoods are installed, negatively affecting the well-being of people occupying the rooms. In order to obviate this drawback, it has been suggested to use extractor hoods provided with a silencing chamber upstream of the extractor element. The silencing chambers, however, make extractor hoods more complicated, expensive and bulky. The aim of the present invention is to solve the above problem, by providing a device which allows to effectively silence extractor hoods and the like by means of a structure which is easy to provide and to assemble and does not entail an increase in bulk. Within the scope of this aim, an object of the present invention is to provide a silencing device which is simple in concept, easy to maintain, safely reliable in operation, versatile in use and has a relatively low cost. This aim, this object and others which will become apparent hereinafter are achieved, according to the invention, by a device for silencing extractor hoods and the like which comprise a body designed to collect fumes and provided, in an upper part thereof, with a discharge hole which is meant for connection to a vent pipe for said fumes and is internally provided with an extractor element, characterized in that it comprises at least one silencing element made of sound-deadening material which is shaped like a cap and is provided with an intake which is directed downward in the assembly position, said silencing element being suitable to be associated with a respective intake of said extractor element. Further characteristics and advantages of the invention will become apparent from the following detailed description of a preferred embodiment of the device for silencing extractor hoods and the like, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a schematic sectional view, taken along a vertical plane, of an extractor hood provided with the silencing device according to the invention; Figure 2 is a perspective view of a silencing element of the extractor hood; Figures 3, 4 and 5 are respectively a sectional side view, a front view and a bottom view of the silencing element; Figure 6 is a perspective view of a second embodiment of the silencing element of the extractor hood; Figure 7 is a sectional view, taken along a vertical plane, of a portion of the silencing element of Figure 6; Figure 8 is a corresponding plan view thereof; Figure 9 is a schematic sectional view, taken along a vertical plane, of a third embodiment of the extractor hood provided with the silencing device according to the invention; Figure 10 is a perspective view of a silencing element used in the extractor hood of Figure 9; Figures 11, 12 and 13 are respectively a side view, a front view and a plan view of said silencing element. Initially with reference to Figure 1, the reference numeral 1 generally designates an extractor hood for cookers which is constituted, in a known manner, by a pyramid-shaped body 10 designed to collect the fumes and having, in its upper part, a discharge hole suitable for connection to a cylindrical vent pipe 11. An element 12 for covering the vent pipe 11 is suitable to be applied above the upper base of the body 10. The covering element 12. is preferably constituted by two or more sheet metal profiled elements which are coupled telescopically. An extractor element 2, constituted by a fan of the centrifugal type, is accommodated inside the body 10 of the hood. The fan 2 has two mutually opposite intakes and a discharge outlet which is connected to said vent pipe 11. The intakes and the outlet have a generally circular shape. At least one silencing element 3 and preferably respective silencing elements 3 made of sound-deadening material are associated with the mutually opposite intakes of the fan 2; said silencing elements are shaped like a cap and have a corresponding intake which is directed downward upon assembly. As shown in detail in Figures 2, 3, 4 and 5, the silencing element 3 is constituted by a pair of shells 31 and 32 which are suitable to be associated, at a respective flanged edge 31a and 32a, with a mutual coupling ring 30 by virtue of suitable screw means. A flange 33 is push-fit coupled to the ring 30 to provide a bayonet-like coupling to the corresponding intake of the fan 2. The first shell 31 forms a sort of inclined flap 31b which covers the second shell 32 in a front region; the second shell 32 has a limited extension, so as to form said intake with respect to the first shell 31. If the extractor hood uses activated-charcoal filters 4 mounted on the intakes of the fan 2 (see Figure 1 again), the silencing elements 3 are push-fitted on filters 4 without the bayonet-coupling flange 33. The shells 31 and 32 of the silencing element 3 are provided by means of an internal layer of sound-deadening fibrous material which is enclosed between two films of washable and impermeable plastics. The plastics films are glued to the layer of fibrous material, preferably so that they do not adhere perfectly, at least on the side directed toward the inside of the cap, to said layer of fibrous material, in order to improve the sound-deadening effect. Advantageously, the silencing device further provides for the use of additional silencing elements 5 made of sound-deadening material which are shaped like a cylindrical sleeve and are suitable to be coupled to the cylindrical vent pipe 11 above the upper base of the body 10 of the hood. As shown in detail in Figures 6, 7 and 8, the additional silencing element 5 is constituted by a pair of semicylindrical shells 51 which are suitable to be mutually joined at a respective vertical flanged edge 51a by virtue of suitable screw means. At the lower end, the sleeve which forms the silencing element 5 is internally provided with a seat 51b which has a wider diameter than the remaining portion of the sleeve and by means of which it is suitable to fit on a corresponding portion 6 of the vent pipe 11. Along the upper edge, the sleeve instead has a cylindrical lip 52 which has a smaller diameter than the remaining portion of the sleeve and is suitable to fit in a corresponding seat 51a formed inside a silencing element which has a similar shape and is superimposed thereon. The shells 51 of the silencing element 5 are formed by an internal layer of sound-deadening fibrous material which is enclosed between two films of washable and impermeable plastics, as provided for the cap-shaped elements 3. The operation of the silencing device is easily understandable from the above description. The cap-shaped silencing elements 3 are fitted over the corresponding intakes of the fan 2, after opening the intake grille of the hood or after removing the grease filters. The silencing elements 3 are fitted, with bayonet-like coupling by means of the flange 33, to the corresponding intake of the fan 2. In order to provide better silencing of the hood, the additional sleeve-shaped silencing element 5 is fitted on the discharge of the fan 2 and is coupled to the vent pipe 11. Indeed, according to operating requirements, it is possible to install one or more silencing elements 5 on the vent pipe 11. The silencing elements 3 and 5 fitted at the intake and at the discharge of the fan 2 allow to reduce noise effectively. In practice, noise reduction is equal to approximately 6 dBA, with a perceived noise level which is four times lower. It should be noted that this result is achieved without increasing the dimensions of the extractor hood. Figure 9 illustrates a different embodiment of the extractor hood, provided with a smaller body 10. In this case, in the silencing device silencing elements made of sound-deadening material, constituted by a single shell 34, are fitted onto the outlets of the fan 2. As shown in Figures 10, 11, 12 and 13, the shell 34 forms a sort of inclined flap which forms said intake in a downward region. The shell 34 can be associated, at a respective flanged edge 34a, with the ring 30, to which the flange 33 for bayonet coupling to the corresponding intake of the fan 2 is push-fit coupled. In this case, noise reduction is equal to approximately 5 dBA. In conclusion, the device according to the invention achieves the aim of effectively silencing extractor hoods and the like by means of a structure which can be provided easily, is easy to assemble and does not entail increases in the dimensions or changes to the aesthetic appearance of the hood. The fact is stressed that the above-described silencing elements 3 and 5 are impermeable to grease and are washable. In particular, the caps 3 can be periodically washed with soap and water after removing them from the hood, by virtue of the bayonet coupling. The silencing elements 3 and 5 further have self-extinguishing characteristics which allow their rating in the V0 class. Another advantage offered by the device is that it also allows application to extractor hoods that are already in use by marketing a suitable kit which preferably comprises a pair of cap elements 3 and a cylindrical sleeve element 5. In the practical embodiment of the invention, the materials used, as well as the shapes and the dimensions, may be any according to requirements. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: A device for silencing extractor hoods and the like which comprise a body designed to collect fumes and provided, in an upper part thereof, with a discharge hole which is meant for connection to a vent pipe for said fumes and is internally provided with an extractor element, characterized in that it comprises at least one silencing element made of sound-deadening material which is shaped like a cap and is provided with an intake which is directed downward in the assembly position, said silencing element being suitable to be associated with a respective intake of said extractor element. The device according to claim 1, characterized in that said silencing element is constituted by a pair of shells which are associated at a respective flanged edge with a mutual coupling ring. The device according to claim 2, characterized in that a flange is push-fit coupled to said ring to provide bayonet coupling to a corresponding intake of the extractor element. The device according to claim 2, characterized in that said pair of shells comprises a first shell which forms a sort of inclined flap which is suitable to cover, in a front region, a second shell which has a reduced extension so as to form an intake with respect to said first shell. The device according to claim 2, characterized in that said shells of the silencing element are provided by an internal layer of sound-deadening fibrous material which is enclosed between two films of washable and impermeable plastics. The device according to claim 1, characterized in that it comprises an additional silencing element made of sound-deadening material which is shaped like a cylindrical sleeve and is suitable to be coupled to said vent pipe of said extractor element above the upper base of said body of the hood. The device according to claim 6, characterized in that said additional silencing element is constituted by a pair of semicylindrical shells which are suitable to be mutually joined at a respective vertical flanged edge. The device according to claim 7, characterized in that said additional silencing element has, along its upper edge, a cylindrical lip which has a reduced diameter and is suitable to fit in a corresponding seat formed inside a further silencing element which has a similar shape and is superimposed thereon. The device according to claim 1, characterized in that said silencing element is constituted by a shell which forms a sort of inclined flap suitable to form said intake in a downward region.

Inventors: GALASSI ALVARO, GALASSI, ALVARO
Applicants: FABER SPA, FABER S.P.A.
Application year: 1999
Main classification: F24C15
IPC codes: F24C15