EP1843107A1

EP1843107A1 - Sound-proofing device and method for constructing it

Info

Publication number: EP1843107A1
Application number: EP06126434A
Authority: EP
Inventors: Gianluca Menozzi
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-04-04
Filing date: 2006-12-18
Publication date: 2007-10-10
Anticipated expiration: 2026-12-18
Also published as: EP1843107B1; ES2317449T3; ITPR20060030A1; DE602006003629D1; ATE414244T1; PT1843107E

Abstract

A sound-proofing device applicable to an air passage conduit (2) comprises a compact / single block sound-absorbing body (3), defining a passage for air and able to be inserted inside the conduit (2); the body (3) defines at least one baffle (5) facing the interior of said passage. An apparatus for sound-proofing an indoor space, communicating with the exterior through an air passage conduit (2) situated inside a vertical wall (6), comprises a sound-proofing device (1) inserted within the conduit (2), the sound-proofing device (1) having longitudinal development along an axis lying in a plane defined by said wall (6).
In the prior art, devices for sound-proofing air passage conduits have a structure comprising a pair of coaxial metal shields, defining within them a hollow space containing sound-absorbing material in crumbled form.

Description

The present invention relates to a sound-proofing device, applicable to an air passage conduit, and to a method for constructing it.
In other words, the present invention relates to a silencer for ventilation and air passage holes.
In the field of sound proofing, the use is known of sound-absorbing materials, i.e. materials able to absorb the sound waves that come in contact therewith. In particular, the absorption effect consists of a transformation into thermal energy of the acoustic energy associated with the sound waves that propagate in a fluid (e.g., air), because of the "rubbing" of the fluid with the sound-absorbing material. Said phenomenon is exploited in different technical solutions, e.g. motorway sound barriers, sound-proof booths and sound-absorbing shields.
The present invention pertains, in particular, to air passage silencers, i.e. sound-proofing devices, based on the sound absorption principle, able to be inserted in conduits through which flows air (or other gaseous fluids channelled within said conduits).
In this field, there are known technical solutions, prevalently used in industrial settings, whereby, within the conduit to be insulated from the acoustic viewpoint, is placed a pair of coaxial metallic shields, defining a hollow space in their interior. Said hollow space is filled with sound-absorbing material in crumbled or thermoformed form; moreover, the whole shield, lapped by the air passing through the conduit, is holed through, so that the air comes in contact with the sound-absorbing material contained in the hollow space.
However, said solutions have some drawbacks. In particular, said silencers are poorly effective, in relation to their length. It is well known that the absorption of the sound associated with a flow of fluid travelling through a conduit is the greater, the more extensive the surface of sound-absorbing material lapped by the fluid itself; in this light, the presence of the shield, albeit holed, reduces the useful surface area for absorption purposes, thus making it necessary to employ longer (and hence bulkier and costlier) silencers.
Moreover, it should be considered that, when the diameter of the conduit is relatively large (e.g. greater than 10 - 11 cm or with cross section greater than 80 - 100 cm²), the absorption capacity of the silencer is reduced, especially with respect to high frequency sound components (e.g. 1000 ÷ 2000 Hz). This limitation is particular relevant if it is necessary to insulate acoustically a conduit having its development in a dividing wall, such as a wall separating an interior space from the outside. In such situations, typically, conduits have a limited length and a diameter set by specific standards (e.g., one can consider the passages made in kitchens to place them in communication with the exterior, for safety reasons, which must necessarily have sections of no less than 100 cm²).
An object of the present invention is to eliminate the aforesaid drawbacks and to make available a sound-proofing device, together with a method for constructing it, that is efficient and economical, also in relation to its length.
Said object is fully achieved by the device and by the method of the present invention, which are characterised by the content of the claims set out below.
This and other characteristics shall become more readily apparent from the following description of a preferred embodiment, illustrated purely by way of non limiting example in the accompanying drawing tables, in which:

Figure 1 shows a top open view of a device according to the present invention, inserted in a wall;
Figure 2 shows a cross section view of the device of Figure 1;
Figure 3 shows the device of Figure 2, according to a different embodiment;
Figure 4 shows a perspective view of the device of Figure 1.

In the figures, the numeral 1 designates a sound-proofing device applicable to an air passage conduit 2, according to the present invention. The device 1 originally comprises a compact / single block sound-absorbing body 3, defining a passage for air and able to be inserted inside the conduit 2.
Moreover, the device 1 comprises a layer 4 for coating the outer surface of the body 3, serving a mechanical protection function; said layer is preferably, but not necessarily, made of PVC or, more preferably, of Polypropylene.
The body 3 is preferably made of rock wool. Alternatively, the body 3 can be made of other materials having sound-absorbing properties, e.g. PP (polypropylene) or PET (polyethylene terephthalate), open-cell polyurethane, polyester or polyethylene tetraphthalate, melamine resin. It should be noted that sound-absorbing materials such as PP and PET have the advantage of being antiseptic, but, with respect to rock wool, they have the disadvantage of being flammable. In particular, with regard to the sound-absorbing material used, preferably bio-soluble rock wool, non combustible in Euroclass A1 according to the EN 13501 Standard, is employed. It should be noted that the thermo-chemical characteristics of the natural rocks, that are used as a raw material to produce bio-soluble rock wool, advantageously enable to obtain a mineral fibre that is acid-proof, cannot putrefy and is water-repellent. Therefore, the rock wool preferably used as sound-proofing material within the device 1 is a material that does not contain hazardous components, is not harmful to human health and has been tested as a bio-soluble material in accordance with note Q of European directive 97/69/EC.
It should be noted that the body 3 defines in its interior a passage having, preferably, cylindrical shape, i.e. with substantially circular cross section. It should be noted that the body 3 and the passage defined by the body 3 may also have different shapes, e.g. shapes providing for an oval, square, rectangular or other cross section. More preferably, the body 3 internally defines a passage having oval or elliptical section.
Moreover, in the preferred embodiment illustrated herein, the body 3 defines at least one baffle 5 facing the interior of said passage. Said at least one baffle has the function of increasing, advantageously, the surface of the body 3 made of sound-proofing material lapped by the fluid flowing through the passage. It should be noted that the baffle 5 is a part of the body 3, which constitutes a single compact block.
The present invention also makes available a method for obtaining a sound-proofing device 1 applicable to a conduit 2 for the passage of air (or of other gaseous fluids).
Said method comprises the following steps:

preparing a compact block of sound-proofing material;
extracting, from said block, a compact / single block body 3 defining a passage for air and able to be inserted inside the conduit 2.

Said compact block is preferably constituted by rock wool, but it can also be constituted by other materials, e.g. PP or PET. It should be noted that, if PP or PET is used as sound-absorbing material, said compact block is obtained by compacting portions of PP or PET in crumbled form with heat, according to a substantially known technique.
The step of extracting the body 3 from said compact block preferably comprises a treatment with rotating abrasive wire. In particular, said step of extracting the body 3 from the compact block originally comprises forming at least one baffle 5, defined by the body 3 and facing the interior of the passage defined internally by the body 3 itself.
The present invention also makes available an apparatus for sound-proofing an interior space communicating with the exterior through an air passage conduit 2 situated inside a vertical wall 6.
Said apparatus comprises a sound-proofing device 1 inserted inside the conduit 5. Said device 1 is a device as described above, i.e. obtained according to a method of the kind described above.
In particular, the apparatus originally provides for the sound-proofing device to have a longitudinal development along an axis lying in a plane defined by said wall 6. This entails that the conduit 2 in turn has a longitudinal development according to an axis lying in the plane defined by the wall 6. In this way, it is possible to obtain a conduit 2 (and hence a sound-proofing device 1) of greater length than the thickness of the wall 6. This entails that the conduit 2 has an inlet and an outlet that are not aligned, i.e. distanced by a quantity equal to the development of the conduit 2 along said axis (lying in the plane defined by the vertical wall 6).
In this regard, it should be noted that the apparatus also originally comprises a first and a second junction element 7, connected to a first and to a second end of the sound-proofing device 1, respectively. Moreover, said junction elements 7 define variations in the section of the conduit 2. This advantageously enables to maintain constant along the conduit 2 the section useful for the passage of air, in spite of the presence of the sound-proofing device 1, inserted within a portion of the conduit 2. In the preferred embodiment illustrated herein, the junction elements 7 are so shaped as to place in communication portions of conduit 2 arranged substantially at right angles to each other.
It should also be noted that, in the preferred embodiment illustrated herein, the conduit 2 has an inlet and an outlet that are mutually distanced by a quantity substantially equal to the length of the sound-proofing device 1. In other words, the sound-proofing device 1 has a length that is substantially equal to the development of the conduit 2 along said axis lying in the plane defined by the vertical wall 6. This advantageously enables to optimise the efficiency of the sound-proofing device 1 with respect to the length of the conduit 2.
Therefore, the present invention enables to obtain the following advantages.
In the first place, the sound-proofing device 1 of the invention enables to sound-proof an air passage conduit in particularly efficient and economical fashion, even if the conduit (or the portion of conduit exploitable for the insertion of the sound-proofing device) has limited length. This advantage is originally obtained thanks to the fact that the device 1 comprises a body 3 made of single-block sound-proofing material, having an inner surface in contact with the air passing through the conduit that is entirely constituted by sound-absorbing material, with no need to interpose sound-reflecting surfaces or grids.
Moreover, the sound-proofing device is particularly effective, from the viewpoint of sound attenuation, also for high-frequency sound components, whilst assuring a sizeable section for the passage of air (e.g. greater than 100 cm²), thanks to the fact that the body 3 made of single-block sound-proofing material defines at least one baffle 5, also made of sound-absorbing material, facing the interior of the air passage internal to the body 3.
The method of the invention advantageously enables to obtain a sound-proofing device 1 having said characteristics in particularly efficient and economical fashion, obtaining a muffler (constituted by a body made of sound-absorbing material) from a single compact block of sound-absorbing material.
Said method, exploiting a work technique with rotating abrasive wire, enables in simple and economical fashion to obtain a body 3 made of sound-absorbing material defining a baffle 5 (facing the interior of the air passage internal to the body 3), said baffle 5 being obtained together with the rest of the body 3 in a single work process. This advantageously enables to avoid having sound-reflecting parts inside the device 1.
The sound-proofing device of the invention advantageously enables effectively to sound-proof spaces such as apartment kitchens, which are mandatorily placed in communication with the exterior through conduits with pre-set section obtained within vertical walls. Said result is originally obtained thanks to the constructive features of the sound-proofing device 1 which make it particularly efficient, even if the device 1 has a relatively reduced length and a relatively large air passage section (in accordance with safety standards).
Figure 3 shows a particularly effective and advantageous embodiment of the present invention.
According to said embodiment, the sound-proofing device 1 comprises a body 3 made of sound-absorbing material having oval or elliptical section and defining a baffle 5 with oval or elliptical section.
The fact that the body 3 and the baffle 5 have oval or elliptical shaped sections is particularly advantageous, because it allows, for equal net air passage section, a particularly sizeable sound level reduction, especially at determined frequencies.
Thanks to the use of a body 3 and a baffle 5 with oval or elliptical shape, an acoustic insulation of about 49 dB is assured.
Moreover, said oval or elliptical shape of the baffle 5 and of the body 3 enables to best exploit space inside the wall in which the device 1 is inserted (since the wall extend to a far greater extent in height / width, rather than thickness).

Claims

Sound-proofing device (1) applicable to an air passage conduit (2), characterised in that it comprises a compact / single block sound-absorbing body (3), defining a passage for air and able to be inserted inside the conduit (2).
Device as claimed in claim 1, characterised in that it comprises a layer (4) made of PVC for coating the outer surface of the body.
Device as claimed in claim 1 or 2, characterised in that it said body (3) is made of rock wool.
Device as claimed in claim 1 or 2, characterised in that it said body (3) is made of PP.
Device as claimed in claim 1 or 2, characterised in that it said body (3) is made of PET.
Device as claimed in any of the previous claims, characterised in that said passage has circular or oval/elliptical cross section.
Device as claimed in any of the previous claims, characterised in that the body (3) defines at least one baffle (5) facing the interior of said passage.
Method for obtaining a sound-proofing device (1) applicable to an air passage conduit (2),
characterised in that it comprises the following steps:
- preparing a compact block of sound-proofing material;

- extracting, from said block, a compact / single block body (3) defining a passage for air and able to be inserted inside the conduit (2).
Method as claimed in claim 8, wherein said sound-absorbing material is rock wool.
Method as claimed in claim 8 or 9, characterised in that the extraction step comprises a treatment by means of rotating abrasive wire.
Method as claimed in any of the claims 8 through 10, characterised in that the step of extracting said body (10) comprises the formation of at least one baffle (5), defined by the body (3) and facing the interior of said passage.
Apparatus for sound-proofing an interior space communicating with the exterior through an air passage conduit (2) situated inside a vertical wall (6),
characterised in that it comprises a sound-proofing device (1) inserted inside the conduit (2), said device 1 being a device as claimed in any of the claims 1 through 7, or obtained by a method as claimed in one of the claims 8 through 11.
Apparatus as claimed in claim 12, characterised in that the sound-proofing device (1) has a longitudinal development along an axis lying in a plane defined by said wall (6).
Apparatus as claimed in claim 12 or 13, characterised in that it comprises a first and a second junction element (7), connected to a first and to a second end of the sound-proofing device (1), respectively.
Apparatus as claimed in claim 14, characterised in that said junction elements (7) define variations in the section of the conduit (2).
Apparatus as claimed in claim 14 or 15, characterised in that said junction elements (7) are able to place in communication portions of conduit (2) that are arranged substantially at right angles to each other.
Apparatus as claimed in any of the claims 12 through 16, characterised in that said conduit (2) has an inlet and an outlet that are mutually distanced by a quantity substantially equal to the length of the sound-proofing device (1).