Acoustic attenuation device

Abstract

Acoustic attenuation device configured to be mounted on a motor vehicle air intake, this device comprising a set of walls defining a flow duct for an air flow arranged for the flow of an air flow generated by the air intake, characterized in that at least one of the walls of the flow duct comprises at least one acoustic attenuation member, said acoustic attenuation member comprising at least one cavity and a neck connecting the cavity to the duct, characterized in that the acoustic attenuation member comprises: a barrier element arranged to prevent the passage of a foreign body into the cavity of the acoustic attenuation member, and / ora foreign body evacuation path in communication with an inclined bottom of the cavity to allow a foreign body present in the cavity to be evacuated from the cavity via this evacuation path. Abstract figure: Fig. 4

Description

Title of the invention: Acoustic attenuation device

[0001] The subject of the invention is an acoustic attenuation device for an air intake of a motor vehicle, a ventilation, heating and / or air conditioning installation of a motor vehicle which comprises such an acoustic attenuation device, as well as a front end module of a motor vehicle which comprises said acoustic attenuation device.

[0002] Generally, a motor vehicle comprises an air inlet in the form of an opening located on the front face of said motor vehicle. The incoming air is used to enable heat exchange between it and the cooling system of the motor vehicle, said cooling system being located near the front face of said vehicle. More specifically, the air entering the engine compartment of the motor vehicle is guided by conduits towards the cooling system of said motor vehicle to enable heat exchange between the incoming air and the heat exchanger of the cooling system. It is important to minimize losses of air flow between the air inlet and the heat exchanger.Indeed, any air flow entering the interior of the vehicle, and escaping towards the engine compartment before having contributed to the heat exchange inside the motor vehicle, negatively influences the air resistance coefficient of said motor vehicle.

[0003] It is known to use air guides in the form of a duct generally made of plastic or other flexible material connecting the air inlet to the cooling system. When air circulates within this duct, in particular when the motor-fan unit of the cooling system is activated to ensure the cooling of the batteries in the case of an electric vehicle, noise pollution is generated. Such a duct ensures the flow and distribution of an air flow. Noise pollution is generated in such ducts, in fact, the acoustic waves generated by the motor-fan unit propagate along the air duct and radiate towards the front of the vehicle.

[0004] To overcome this, it is known to equip these air circulation ducts with at least one acoustic attenuation member in order to reduce the acoustic energy which is propagated and thus reduce the noise radiated at the outlet of these ducts, in particular when charging an electric vehicle. To enable a reduction in acoustic waves, this type of acoustic attenuation member comprises a Helmholtz resonator making it possible to reduce the acoustic energy radiated at the front of the vehicle at a given frequency.

[0005] A Helmholtz resonator comprises in a known manner a cavity and a neck connecting the cavity to an airflow duct. There is therefore a risk that dust, mud or water may enter the resonator cavity. Such intrusion has the effect of altering the attenuation performance of Helmholtz resonators and rendering them ineffective.

[0006] In this context, the present invention proposes a solution for preventing the intrusion of water, mud or dust into at least one acoustic attenuation member of the Helmholtz resonator type arranged on an air flow duct, in particular on the front panel module of a motor vehicle, so as to preserve its effectiveness.

[0007] The invention relates to an acoustic attenuation device configured to be mounted on a motor vehicle air intake, this device comprising a set of walls defining a flow duct for an air flow arranged for the flow of an air flow generated by the air intake, characterized in that at least one of the walls of the flow duct comprises at least one acoustic attenuation member, said acoustic attenuation member comprising at least one cavity and a neck connecting the cavity to the duct, characterized in that the acoustic attenuation member comprises: - a barrier element arranged to prevent the passage of a foreign body into the cavity of the acoustic attenuation member, and / or - a foreign body evacuation path in communication with an inclined bottom of the cavity to allow a foreign body present in the cavity to be evacuated from the cavity by this evacuation path.

[0008] Thus, the device according to the invention makes it possible to prevent the entry of foreign bodies into the cavity of the acoustic attenuation members, or when bodies have entered to facilitate their evacuation, so that the acoustic attenuation members remain clean and thus retain all their effectiveness.

[0009] By foreign body, it is understood here in a non-limiting manner water, mud or even dust.

[0010] According to one aspect of the invention, the acoustic attenuation member is a Helmholtz resonator.

[0011] According to one aspect of the invention, the neck of the acoustic attenuation member opens into the air flow duct, forming an opening in said duct.

[0012] According to one aspect of the invention, the neck has a circular section.

[0013] According to one aspect of the invention, the diameter of the neck is between two millimeters and a half and thirty millimeters.

[0014] According to one aspect of the invention, the neck has a height measured along a main extension axis of the neck, the height of the neck being between one millimeter and twenty-five millimeters.

[0015] According to another aspect of the invention, the neck may have an oval or rectangular section whose width is measured in the direction of flow of the air flow in the duct and the length is measured in a direction perpendicular to the width.

[0016] According to one aspect of the invention, the cavity comprises at least four faces, the neck being arranged on one of the faces.

[0017] According to one aspect of the invention, one of the faces of the cavity forms the inclined bottom.

[0018] According to one aspect of the invention, at least one cavity of the network of organs acoustic attenuation has a parallelepiped shape.

[0019] According to one aspect of the invention, the cavity of the acoustic attenuation member has a rectangular section

[0020] According to one aspect of the invention, the device comprises a network of acoustic attenuation members arranged on at least one wall of the air flow duct, the acoustic attenuation members of the network being distributed at least parallel to the direction of air flow.

[0021] According to one aspect of the invention, the network of acoustic attenuation members comprises a first row of substantially similar acoustic attenuation members extending along a first direction perpendicular to the airflow direction, the network of acoustic attenuation members comprising at least a second row of substantially similar acoustic attenuation members extending along a second direction perpendicular to the first direction and to the airflow direction.

[0022] Alternatively, the second row of acoustic attenuation members extending along a second direction perpendicular to the first direction and to the air flow direction comprises acoustic attenuation members whose cavity volume and / or neck diameter, and / or neck height are different from those of the first row.

[0023] According to one aspect of the invention, the network of acoustic attenuation members is organized in the form of a matrix comprising at least two rows of acoustic attenuation members, and where the acoustic attenuation members of the at least two rows are respectively aligned along the direction of air flow. It is understood that each acoustic attenuation member of one of the two rows of acoustic attenuation members is aligned with at least one acoustic attenuation member of the other of the two rows of acoustic attenuation members, along a direction perpendicular to the direction of air flow.

[0024] According to another optional characteristic of the invention, the network of acoustic attenuation members extends over at least two, preferably at least three, preferably at least four walls of the air flow duct.

[0025] According to one aspect of the invention, the barrier element is impermeable to water and / or dust.

[0026] According to one aspect of the invention, the barrier element is chosen from a membrane or a hydrophobic felt.

[0027] According to one aspect of the invention, the barrier element at least partially covers the opening formed by the neck opening into the conduit. Preferably, the barrier element covers the entire opening formed by the neck opening into the conduit.

[0028] According to one aspect of the invention, when the device comprises a network of acoustic attenuation members, the neck of each attenuation member opens onto the conduit, forming an opening.

[0029] According to one aspect of the invention, the barrier element has low resistivity to the passage of air and acoustic waves.

[0030] According to one aspect of the invention, the neck has an end section adjacent to the opening formed by the neck opening into the conduit.

[0031] According to one aspect of the invention, the barrier element is arranged between said end section of the neck and the opening formed by the neck opening into the conduit.

[0032] According to one aspect of the invention, the barrier element is fixed to the end section of the neck by gluing to said end section.

[0033] Alternatively, the barrier element is arranged on the conduit so as to cover the opening formed by the neck opening into the conduit.

[0034] According to one aspect of the invention, the barrier element is arranged to cover only one opening. In this case, the device may comprise as many barrier elements as it comprises openings formed by necks opening into the air flow duct.

[0035] Alternatively, the barrier element is arranged to cover a plurality of openings formed by the necks of a plurality of gold opening into the air flow duct. In this case, the barrier element may be arranged to cover all of the openings of the air regulation device, or all of the openings of the same row.

[0036] According to one aspect of the invention, the acoustic attenuation device comprises a single barrier element common to all the openings formed by the necks opening into the air flow duct.

[0037] According to one aspect of the invention, the barrier element is fixed to the wall of the air flow duct comprising the openings by gluing.

[0038] According to one aspect of the invention, the evacuation path is formed at least in part by at least a part of the inclined bottom.

[0039] According to one aspect of the invention, the inclined bottom in communication with the evacuation path is arranged to orient the foreign body out of the cavity of the acoustic attenuation member.

[0040] According to one aspect of the invention, the inclined bottom comprises at least one inclination relative to a transverse plane of the device, the bottom thus having a so-called high region and a so-called low region, the high region being above the low region when the transverse plane of the device is parallel to a horizontal plane.

[0041] According to one aspect of the invention, the angle of inclination of the inclined bottom relative to the transverse plane is between 1° and 20°

[0042] According to one aspect of the invention, the inclined bottom comprises at least two inclinations, preferably 4 inclinations, relative to the transverse plane such that the inclined bottom has a convex shape comprising a so-called high region and a so-called low region. In this case, the high region is for example arranged at the periphery of the inclined bottom and the low region is for example arranged in a central zone of the inclined bottom. The angles of inclination of each of the inclinations may be identical or different.

[0043] According to one aspect of the invention, the inclined bottom has a single inclination relative to the transverse plane such that the high region is disposed on one side of the inclined bottom and the low region is disposed on the opposite side of the inclined bottom.

[0044] According to one aspect of the invention, the evacuation path is formed at least in part by a foreign body evacuation orifice, said evacuation orifice being in communication with the lower region of the inclined bottom.

[0045] According to one aspect of the invention, the lower region of the inclined bottom and the discharge orifice are connected by a drain.

[0046] According to one aspect of the invention, when the acoustic attenuation member is arranged in the duct such that the cavity is arranged above the neck, the inclined bottom corresponds to the face of the cavity on which the neck is arranged. This is for example the case when the acoustic attenuation member is arranged on a so-called upper wall of the duct.

[0047] According to one aspect of the invention, when the acoustic attenuation member is arranged in the duct such that the cavity is arranged above the neck, the discharge orifice is formed by the opening formed by the neck opening into the flow duct of an air flow, and the drain is formed by said neck. In other words, the opening formed by the neck opening into the flow duct acts as a discharge orifice and the neck acts as a drain. In this case, the neck is arranged on the lower region of the inclined bottom.

[0048] According to one aspect of the invention, when the acoustic attenuation member is arranged in the duct such that the cavity is arranged below the neck, the inclined bottom corresponds to a face of the cavity opposite that on which the neck is arranged. This is for example the case when the acoustic attenuation member is arranged on a so-called lower wall of the duct.

[0049] According to one aspect of the invention, when the acoustic attenuation member is arranged in the duct such that the cavity is arranged below the neck, the drain is distinct from the neck and the discharge orifice is distinct from the opening formed by the neck opening into the duct.

[0050] According to one aspect of the invention, when the acoustic attenuation member is arranged in the duct such that the cavity is arranged next to the neck, the neck opens onto one side of the inclined bottom. This is for example the case when the acoustic attenuation member is arranged on a so-called side wall of the duct.

[0051] According to one aspect of the invention, when the acoustic attenuation member is arranged in the duct such that the cavity is arranged next to the neck, said neck is arranged on the lowest region of the inclined bottom.

[0052] According to one aspect of the invention, when the acoustic attenuation member is arranged in the duct such that the cavity is arranged next to the neck, the discharge orifice is formed by the opening formed by the neck opening into the duct for the flow of an air flow, and the drain is formed by said neck.

[0053] According to one aspect of the invention, when a foreign body enters the cavity, in particular through the opening formed by the neck opening into the air flow duct, it moves towards the inclined bottom, said inclined bottom being arranged to direct this foreign body towards the drain then towards the evacuation orifice by the action of gravity.

[0054] The present invention also relates to a ventilation, heating and / or air conditioning installation for a motor vehicle which comprises an acoustic attenuation device as described in the present document and an air inlet, the acoustic attenuation device being installed in the air inlet of the ventilation, heating and / or air conditioning installation.

[0055] The present invention also relates to a front panel module of a motor vehicle which comprises an acoustic attenuation device as described in the present document and an air inlet, the acoustic attenuation device being installed in the air inlet on the front panel of the motor vehicle.

[0056] Other characteristics and advantages of the present invention will appear more clearly on reading the following description, provided for illustrative and non-limiting purposes, and the appended drawings in which:

[0057] [Fig-1] [Fig.l] is a schematic representation of an attenuation device acoustic,

[0058] [Fig.2] [Fig.2] is a schematic representation of an acoustic attenuation member included in the acoustic attenuation device according to a first embodiment and configured to be arranged on the upper wall of an air flow duct,

[0059] [Fig.3] [Fig.3] is a schematic representation of an attenuation member acoustic included in the acoustic attenuation device according to a first embodiment and configured to be arranged on a side wall of an air flow duct,

[0060] [Fig.4] [Fig.4] is a schematic representation of an attenuation member acoustic included in the acoustic attenuation device according to a first embodiment and configured to be arranged on the lower wall of an air flow duct,

[0061] [Fig.5] [Fig.5] is a schematic representation of an organ variant acoustic attenuation as described in [Fig.4],

[0062] [Fig.6] [Fig.6] is a schematic representation of an attenuation member acoustics included in the acoustic attenuation device according to a second embodiment,

[0063] [Fig.7] [Fig.7] is a schematic representation of a variant of an organ acoustic attenuation according to [Fig.6],

[0064] [Fig.8] [Fig.8] is a schematic representation of an attenuation device acoustics comprising acoustic attenuation members according to figures 6 or 7.

[0065] [Fig.l] represents an acoustic attenuation device 1 comprising a set of walls 2 defining a flow duct 3 for an air flow F arranged for the flow of an air flow F generated by the air inlet 5. The walls 2 of the flow duct 3 here comprise a plurality of acoustic attenuation members 4 arranged to reduce the noise generated by the air inlet. The acoustic attenuation members 4 are described in more detail in Figures 2 to 6. In the embodiment of [Fig.l], each wall 2 of the device 1 comprises several acoustic attenuation members 4. In an embodiment not shown here, the acoustic attenuation device 1 could comprise a network of acoustic attenuation members 4 arranged on at least one wall 2 of the air flow duct 3, the acoustic attenuation members of the network being distributed at least parallel to the direction of air flow.

[0066] Figures 2 to 7 represent an acoustic attenuation member of the acoustic attenuation device represented for example in [Fig.l]. The acoustic attenuation members represented are Helmholtz resonators. In all the figures, the acoustic attenuation member 4 is arranged on a wall 2 of the air flow duct 3. The acoustic attenuation member 4 comprises a cavity 6 and a neck 7 connecting the cavity 6 to the duct 3. The neck 7 of the acoustic attenuation member 4 opens into the air flow duct by forming an opening 9 in said duct 3, and more precisely in the wall 2 of the duct on which it is arranged. The neck 7 has a circular section. In an embodiment not shown here, the neck 7 could have a section of another shape, for example oval, rectangular... The diameter of the neck 7 is between 2.5mm and 30mm. The neck 7 has a height measured along a main extension axis X of the neck 7 and the neck 7 generally measures between 1mm and 25mm. The cavity 6 comprises four faces delimiting a volume, and the neck 7 is carried by one of the faces. The cavity 6 has in the embodiments of figures 2 to 7 a parallelepiped shape whose section is rectangular. In another embodiment not shown here, the cavity could have another shape.

[0067] In Figures 2 to 5, the acoustic attenuation member comprises an inclined bottom 8. This inclined bottom 8 is formed by one of the faces of the cavity. The acoustic attenuation member comprises a foreign body evacuation path in communication with an inclined bottom 8 of the cavity 6 to allow said foreign body present in the cavity 6 to be evacuated from the cavity 6 via this evacuation path. The foreign body may for example be mud, dust or even water. The evacuation path is formed in part by the inclined bottom 8. The evacuation path is arranged to direct the foreign body out of the cavity 6 of the acoustic attenuation member. This evacuation path has the function of easily evacuating a foreign body which would have entered the cavity of the acoustic attenuation member for example via the neck 7. The acoustic attenuation member thus remains clean and retains its effectiveness.The inclined bottom comprises at least one inclination relative to a transverse plane P of the device, the angle of inclination of the inclined bottom relative to the transverse plane P being between 1° and 20°. The acoustic attenuation member 4 further comprises an evacuation orifice 12 which is in communication with the inclined bottom 8. The evacuation path is partly formed by the evacuation orifice 12. Thus, a foreign body which has entered the cavity 6 can be evacuated by circulating in the evacuation path formed in particular by the inclined bottom 8 and the outlet orifice 12. The foreign body is evacuated by being oriented towards the outside by the inclined bottom 8 then by the evacuation orifice 12 thanks to gravity.

[0068] In [Fig.2], the inclined bottom 8 has four inclinations of an angle alpha relative to the transverse plane P such that the inclined bottom 8 has a convex shape comprising a high region 10 arranged above a low region 11. The foreign body can be evacuated by the evacuation path by moving from the high region 10 to the low region 11 of the inclined bottom 8. The high region 10 is here arranged on the periphery of the inclined bottom, and the low region 11 is arranged on a central zone of the inclined bottom 8. In this example, the inclinations have the same angle alpha.

[0069] In the embodiment of [Fig.2], the acoustic attenuation member is arranged on the air flow duct 3 in such a way that the cavity 6 is arranged above the neck 7. In this way, the acoustic attenuation member 4 can be arranged on a so-called upper wall of the duct 3. The acoustic attenuation member comprises four faces including the inclined bottom 8 which is in communion with the neck 7 and an opposite face 13 to said neck 7. The discharge orifice 12 is formed by the opening 9 formed by the neck 7 opening into the duct 3 for the flow of an air flow. The neck 7 then forms a drain 13 participating in the evacuation of a foreign body. In other words, the opening formed by the neck opening into the flow duct acts as a discharge orifice and the neck acts as a drain. In this case, the neck is arranged on the lower region of the inclined bottom.

[0070] The foreign body which is in the cavity 6 will thus circulate via the evacuation path by circulating first on the inclined bottom 8, in particular from the upper region 10 to the lower region 11 of the inclined bottom 8, then will be directed towards a drain 13 formed by the neck 7 of the acoustic attenuation member 4 and towards an evacuation orifice 12 formed by the inlet 9 to be evacuated towards the outside.

[0071] The acoustic attenuation member 4 shown in [Fig. 3] comprises an inclined bottom 8 having a single inclination relative to a plane P. The inclined bottom 8 is inclined by an angle alpha of between 1° and 20°. The inclined bottom has a high region 10 and a low region 11, the high region being located on one side of the inclined bottom and the low region 11 being located on the opposite side of the inclined bottom 8.

[0072] The neck 7 is in communication with the inclined bottom 8, and more precisely with the lower region 11 of the inclined plane. The neck 7 extends along a main axis X of the neck substantially parallel to a face 14 of the cavity 6 opposite the inclined bottom 8.

[0073] In [Fig. 3], the acoustic attenuation member 4 is arranged in the duct 3 in such a way that the cavity 6 is arranged next to the neck 7, the neck 7 opening onto one side of the inclined bottom 8. More precisely, the neck 7 is arranged on the lower region 11 of the inclined bottom 8. The acoustic attenuation member 4 shown in [Fig. 3] is for example arranged to be arranged on a side wall of the duct 3 for the flow of an air stream.

[0074] The discharge orifice 12 is here formed by the opening formed by the neck 7 opening into the air flow duct, and the drain 13 is formed by said neck 7.

[0075] In [Fig.4] and in [Fig.5], the acoustic attenuation member is arranged in the duct such that the cavity 6 is arranged below the neck 7, the neck 7 is arranged on a face of the cavity opposite the inclined bottom. The inclined bottom 8 is inclined at an angle alpha relative to a transverse plane P. The inclined bottom 8 has a high region 10 and a low region 11 with which the discharge orifice 12 is in communication. More precisely, the discharge orifice 13 is in communication with the low region 11 of the inclined bottom 8 via a drain 13. Thus, the discharge path here comprises a discharge orifice 12 for the foreign body, said discharge orifice 12 being in communication with the low region 11 of the inclined bottom 7. The drain 13 is here distinct from the neck 7 and the evacuation orifice 12 is distinct from the opening 9 formed by the neck 7 opening into the conduit 3.

[0076] The acoustic attenuation member 4 is arranged in the duct 3 such that the cavity 6 is arranged below the neck 7. Such an attenuation member may be arranged on a lower wall of an air flow duct.

[0077] In [Fig. 4], the inclined bottom 8 comprises only an inclination of an angle alpha between the transverse plane P and the bottom 8. Thus, the inclined bottom has a high region 10 arranged on one side of the inclined bottom 8 and a low region 11 arranged on the opposite side of the inclined bottom 8. The drain 13 and the discharge orifice 12 are arranged on one side of the inclined bottom 8, the side on which the low region 11 is located. The discharge path is formed here in particular of the inclined bottom 8 which guides the foreign body from the high region 10 to the low region 11, as well as the drain 13 and the discharge orifice 12 which lead the foreign body to the outside of the cavity 6.

[0078] In [Fig.5], the inclined bottom 8 has several inclinations of an angle alpha so as to form a cavity 6 of convex shape. The high region 10 is arranged on the periphery of the inclined bottom 6 and the low region 11 is arranged in a central zone of the inclined bottom 8. Thus the foreign body is guided from the peripheral high region 10 towards the central low region 11 and is then evacuated by passing through the drain 13 and the evacuation orifice 12 which are in communication with the central low region 11.

[0079] In all of these embodiments, when a foreign body enters the cavity 6, in particular through the opening 9 formed by the neck 7 opening into the air flow conduit 3, it moves towards the inclined bottom 8, said inclined bottom 8 being arranged to direct this foreign body towards the drain 13 then towards the evacuation orifice 12 by the action of gravity.

[0080] [Fig. 6] represents an acoustic attenuation member 6 comprising a barrier element 15 arranged to prevent the passage of a foreign body into the cavity 6, in particular the passage of water and / or dust. The barrier element 15 may be a membrane or felt impermeable to water and / or dust, having hydrophobic properties and allowing the passage of air. The bottom 8 of the cavity 6 of such an acoustic attenuation member 4 may be straight, in other words not have an inclination.

[0081] In [Fig.6], the barrier element 15 covers the entirety of the opening 9. In another embodiment not shown here, the barrier element could only partially cover the opening 9. More precisely, the barrier element 9 is arranged between the conduit 3 and an end section 16 of the neck 7 which is adjacent to the opening 9 formed by the neck 7 opening into the conduit 3.

[0082] In this example, the acoustic attenuation member is such that the cavity 6 is arranged above the neck 7. The acoustic attenuation member 4 comprising such a barrier element could be arranged differently, in particular by having a cavity arranged below the neck, or next to the neck as is the case in figures 3, 4 and 5.

[0083] [Fig. 7] represents an acoustic attenuation member 4 comprising a barrier element 15 arranged to prevent the passage of a foreign body into the cavity 6 of the acoustic attenuation member 4 as described in particular in [Fig. 6], and a foreign body evacuation path in communication with an inclined bottom 8 of the cavity 6 to allow a foreign body present in the cavity 6 to be evacuated from the cavity 6 via this evacuation path as described in FIGS. 2 to 5.

[0084] [Fig.8] represents an acoustic attenuation device 1 comprising a barrier element 15 which covers all of the openings 9 of all of the acoustic attenuation members 4 which are on the wall 2 of the duct 3.

Claims

Claims

1. Acoustic attenuation device (1) configured to be mounted on an air intake (5) of a motor vehicle, this device (1) comprising a set of walls (2) defining a duct (3) for the flow of an air flow (F) arranged for the flow of an air flow generated by the air intake (5), characterized in that at least one of the walls (2) of the flow duct (3) comprises at least one acoustic attenuation member (4), said acoustic attenuation member (4) comprising at least one cavity (6) and a neck (7) connecting the cavity (6) to the duct (3), characterized in that the acoustic attenuation member (4) comprises: - a barrier element (15) arranged to prevent the passage of a foreign body into the cavity (6) of the acoustic attenuation member (4),and / or - a foreign body evacuation path in communication with an inclined bottom (8) of the cavity (6) to allow a foreign body present in the cavity (6) to be evacuated from the cavity (6) via this evacuation path.,

2. Device according to claim 1, characterized in that the cavity (6) comprises at least four faces, the neck (7) being arranged on one of the faces, one of the faces of the cavity forming the inclined bottom (8).

3. Device according to one of claims 1 or 2, characterized in that the evacuation path is formed at least in part by at least one part of the inclined bottom (8).

4. Device according to one of the preceding claims, characterized in that the inclined bottom (8) comprises at least one inclination relative to a transverse plane (P) of the device, the bottom (8) thus having a so-called high region (10) and a so-called low region (11), the high region (10) being above the low region (11) when the transverse plane (P) of the device is parallel to a horizontal plane.

5. Device according to one of claims 1 to 4, characterized in that the evacuation path is formed at least in part by an evacuation orifice (12) for the foreign body, said evacuation orifice (12) being in communication with the lower region (10) of the inclined bottom (8).

6. Device according to the preceding claim, characterized in that the lower region (11) of the inclined bottom (8) and the discharge orifice (12) are connected by a drain (13).

7. Device according to one of the preceding claims, characterized in that when the acoustic attenuation member (4) is arranged in the conduit (3) in such a way that the cavity (6) is arranged below the neck (5), the drain (13) is separate from the neck (7) and the discharge orifice (12) is separate from the opening (9) formed by the neck (7) opening into the conduit (3).

8. Device according to one of the preceding claims, characterized in that the barrier element (15) is impermeable to water and / or dust.

9. Device according to one of the preceding claims, characterized in that the barrier element (15) is chosen from a membrane or a hydrophobic felt.

10. Device according to one of the preceding claims, characterized in that the barrier element (15) at least partially covers the opening (9) formed by the neck (7) opening into the conduit (3).

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