FR2806515A1 - ACOUSTIC SCREEN AND ITS CONSTITUENT ELEMENTS - Google Patents

Abstract

The invention relates to an acoustic screen intended to combat noise pollution near roads, railways or other sources of noise pollution. The aim of the invention is to provide a noise barrier that is easy to assemble, adaptable to multiple configurations, economical, easy to manufacture and maintain, little mess, aesthetic and efficient in terms of sound insulation.This goal is achieved by the claimed screen which comprises a plurality of elementary curvilinear panels juxtaposed and supported by posts (3). Each panel (2) and each post (3) has a base extended by a convex upper part. Each panel (2) comprises a hollow structure in thermoplastic polymer and an acoustic absorbent material disposed on the internal face of the panel. The invention also relates to the panels and the posts taken individually.

Description

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  ACOUSTIC SCREEN AND ITS CONSTITUENT ELEMENTS

  The field of the invention is that of acoustic or noise barriers that are intended to interrupt the propagation of acoustic waves between a sound source, for example a road, a railway, an airport, a factory, a construction site and a receiver, for example riparian dwellings victims of nuisances

  noise caused by the sources mentioned above.

  The present invention thus relates to a new acoustic screen formed of a plurality of panels

  elementary, joined and supported by poles.

  It is known that the factors limiting the effectiveness of acoustic screens include the residual transmission of sound waves and the diffraction thereof

  by the vertices or sides of these screens.

  Regarding the transmission it is clear that acoustic screens known to date are unable to block the absolute sound waves. The residual transmission, which is comparable to the insulating power of an acoustic screen, can be characterized by the transmission loss index (R) expressing

in decibels (dB (A)).

  The acoustic screen necessarily has a limited perimeter, so that some of the sound waves that propagate in all directions collide with the edges, particularly the top of the screen. The latter thus diffract the sound waves and behaves

  as a secondary source re-emitting in half

  space behind the screen (the shadow area). These sound waves from the secondary diffraction source arrive at the receiver and thereby affect the acoustic gain provided by the screen. This diffraction phenomenon depends on the frequency of the sound waves considered, but also on the position of the source-receiver pair with respect to the screen, as well as the

dimensions of the latter.

  Another physical phenomenon that affects the effectiveness of an acoustic screen is the reflection of sound waves. According to its ability to transmit or absorb the incident acoustic energy, a screen will cause more or less parasitic reflections, which can propagate not to the primary receivers that the screen considered protects, but to receivers located at the opposite of these in relation to the sound source. In the particular case of a road or rail road, these secondary receptors are the residents located in the vicinity of the side opposite to that comprising

the screen in question.

  Acoustic reflection is therefore to be considered in the specifications of an acoustic screen. It is also worth mentioning the acoustic diffusion, as a physical phenomenon involved in the effectiveness of an acoustic screen. Depending on their surface state or the relief, the acoustic screens have a certain diffusion or dispersion of the acoustic energy,

  variable depending on the frequency of the sound waves involved.

  Other elements to consider in the design or production of an acoustic screen include: topography and the nature of the terrain between the screen and the receiver, the dimensions of the screen must be relatively consistent to ensure reasonable efficiency, type and size of sound sources, position of receivers, etc. Other aspects not to be neglected are the cost and the more or less heavy nature of civil engineering operations intended for the installation of acoustic screens, with a view to protecting a site from sources

polluting acoustics.

  The visual impact and integration of acoustic screens in urban or rural landscapes are other specifications in their own right. To complete this specification required for acoustic screens, for example road or rail type, we can mention the following specifications: - durability of acoustic performance - lower maintenance cost - resistance to damage, stability of structure and performance aspect in time - possibility of after-accident repairs or possible displacement in case of widening of track including sound sources - simplicity of associated civil engineering works - ease of assembly of repair or maintenance, especially without interruption Traffic

  - resistance to weather conditions.

  To date, two types of acoustic screens are known: reflective screens and absorbent screens. The most common reflective screens are products made of wood, concrete, glass and polycarbonate panels, these panels being installed between support and joining posts, fixed directly in the ground or on concrete parapets. These different constituent materials can be

associated for the same screen.

  To avoid spurious reflections due to the lack of absorption, these reflective screens can have a

  inclined or curved profile with respect to the ground.

  Figure 1 attached shows an example of this type of known reflective screen formed by panels (a) glass or polycarbonate installed between posts (D) support and junction. These are made for example of metal are fixed via a base or (8) on a parapet (y) made of concrete on the edge

of a road (ú).

  These known reflective acoustic screens do not satisfy the expected specifications for acoustic screens, for example of the road or rail type. First, they are not the most acoustically efficient. The phenomenon of reflection is embarrassing for residents on the opposite side. In addition, their aesthetic characteristics leave something to be desired and they do not integrate well with the landscape,

  street furniture or in rural areas.

  Absorbent screens; they may consist of elements: - of wood concrete (often architected), - formed by perforated metal trays or by lattice containing an absorbent mineral wool, - formed by panels of wood or composite openwork material containing a mineral wool absorbent, - formed by resonator bricks having mineral wool-type absorbent perforations and padding, - of clay foam or expanded clay concrete,

- or plastic.

  Absorbent screens can also be made in the form of vegetated stiffened slopes.

armed earth, for example.

  There are also absorbent screens made

  from combination of the aforementioned elements.

  Absorbent screens generally have satisfactory acoustic performances that are nevertheless perfectible. It should be noted, however, that these absorbent screens suffer in terms of the durability of acoustic performances, their difficulties of assembly and disassembly, the complexity of associated civil engineering works, their sensitivity to frost, rain, wind or

other bad weather.

  The integration of some of these known absorbent screens into urban or rural sites, could it

also, be improved.

  It should also be observed that the known screens that they are reflecting or absorbing only partially take into account the problem of acoustic diffraction on their contours, in particular,

on their summits.

  In such a state of the art, one of the essential objectives of the present invention is to provide a new acoustic or noise-canceling screen which is in particular: easy to mount, adaptable to multiple configurations of sources of noise pollution (roads, railways, industrial sites, airports ...), * reasonable cost price, * easy to manufacture and maintain, * little messy, * aesthetic and well integrated into the landscape, * and above all efficient in terms of acoustic insulation, in terms of reduction of the sound transmission loss index, in terms of limiting the diffraction of sound waves and in terms of limiting reflection and diffusion thanks to a good

absorption power.

  Another essential objective of the invention is to provide a road or rail acoustic screen which is stable over time, in terms of structures,

  acoustic performance and weather resistance.

  Another essential objective of the invention is to provide constituent elements (panels / posts junction and support) for the realization of acoustic screens with the advantageous properties mentioned

above.

  These objectives, among others, are achieved by the present invention, which firstly concerns an acoustic screen comprising a plurality of elementary panels of curvilinear profile, juxtaposed and supported by connecting posts arranged between these panels, characterized in that: that each panel and each post have a base extended by a convex upper part, this base breaking with the convexity of the latter; - and in that each panel comprises:

  * on the one hand, a structure - preferably hollow -

  in thermoplastic polymer material, * and secondly, at least one material (10) acoustic absorbent, preferably disposed on the inner face of the panel and more preferably still in at least one compartment arranged in

the polymer structure.

  The acoustic screen according to the invention is distinguished from the prior art by geometrical characteristics and

  by composition characteristics.

  The combination of a rather reflective thermoplastic polymer and an acoustic absorbent nested in the polymer structure achieves acoustic performance in accordance with the required specifications. In particular, the attenuation index R can be

  advantageously 2 dB (A), preferably 2 dB (A).

  Geometrically, the combination of a substantially rectilinear base (or even preferably slightly concave in its upper part), and a convex shape for the panels and the support and junction posts, gives the screen a original appearance and technically efficient. This form that could be described as "tulip petal" fills a double

aesthetic and technical function.

  Advantageously, each constituent panel of the screen has a substantially rectangular shape in plan view. This preference is not exclusive of other geometric shapes for each quadrilateral panel, triangle, etc. According to an essential characteristic of the invention, the structure of each panel is obtained by rotational molding and consists of a thermoplastic polymer chosen from the group comprising: polyolefins, preferably polyethylenes (PE), polypropylenes (PP), polychrome vinyls (PVC), polystyrenes (PE), polyacrylonitrile-butadiene-styrene (ABS), polyaceto-butyrate cellulose (CAB), poly (meth) acrylates, in particular, polymethacrylates (PMMA), ethylene vinyl polyacetates (EVA) * polyamides (PA) * polycarbonates (PC) * copolymers * and mixtures thereof; * High density PE (HDPE), low density PE (LDPE) and PVC being particularly preferred The fact that the screen according to the invention is made of thermoplastic material, preferably by rotational molding, offers many possibilities in terms of coloring, which can only compete

to its aesthetic qualities.

  Its maintenance is easy. Cleaning using

  pressurized water, as well as

  graffiti are conceivable. This screen offers, moreover, all the required qualities in terms of mechanical strength. It satisfies without any problem

the ten-year guarantee requirement.

  In terms of mounting the panels can be installed either laterally or from above according to the

site constraints.

  Preferably, the acoustic absorbing material is selected from the group consisting of: * rockwool, * lignocellulosic materials, * textile materials,

* composites.

  Advantageously, the compartment or compartments of the polymeric structure intended to contain or containing the acoustic absorbent and are covered with at least one perforated plate thus forming at least a portion of the internal face of each elementary panel, the perforations advantageously representing at least 25%, preferably at least 30% of the surface of the inner face of a panel In terms of absorption, the rate of perforation of the lining and containment plates of the absorbent material is chosen so as to give an area

sufficient absorption.

  The invention will be better understood on reading the

  following description of a non-limiting example of a mode

  preferred embodiment of the acoustic screen that she

  concerned. This detailed description will also

  highlight all the advantages and alternative embodiments of the screen according to the invention. This

  description is made with reference to the accompanying drawing in

  which: - Figure 1 shows a schematic perspective view of a reflecting screen according to the prior art. FIG. 2 is a general perspective view of the noise barrier according to the invention mounted on the edges of a road in order to protect the residents of the

noise.

  FIG. 3a is a perspective view showing an acoustic screen panel according to the invention, one of the two support and joining posts with which this panel cooperates and the base of the base on

which is fixed said post.

  FIG. 3b is a longitudinal partial sectional view from above along plane III-III of FIG. 3a; FIG. 4 is a vertical section along the plane;

vertical II-II of Figure 2.

  FIG. 5a is a perspective view of a panel and a connecting pole according to an alternative embodiment of the invention in which the lateral edge of the panel is of the male type designed for

  cooperate with a H-pole of the female type.

  FIG. 5b is a detail view in longitudinal partial section from above along the V-V plane shown in FIG.

Figure 5a.

  FIG. 2 shows an acoustic screen (1) formed by a plurality of elementary panels (2), two of which are represented in solid lines and one in phantom on the drawing. These elementary panels are joined to each other by their lateral edges (15) designed to cooperate with posts (3) support and junction, fixed to the ground on the pads or foundation plates (4). This modular noise screen (1) is arranged between on the one hand, a sound source which can be constituted for example by motor vehicles, trains, aircraft or a noisy industrial site ...... and d on the other hand sound receivers likely to be hindered by the noise emitted by the sources, these receivers being able to be for example, residents living near these noise nuisances. In this case, the acoustic screen (1) is disposed on the shoulder on either side of a road or carriageway designated by the general reference (5), or on the central ground of

  roads or structures.

  As shown in Figures 2, 3a and 4, the elementary panels (2) and the connecting posts (3) have, at least partially, substantially the same curvilinear profile. It is more apparent from Figure 4 showing a panel (2) that this curvilinear profile can be decomposed into at least two sections, preferably 3 (ABC). Thus, each elementary panel (2) and each pole (3) comprises a base formed by a lower section (A) and a median section (B), this base (AB) being extended by a convex upper portion corresponding to the section (C). This base (AB) breaks with the convexity of the convex upper part (C). FIGS. 2 and 3a show that the convex upper part (C) of the posts (3) is not as long, in this example, as

  that of the elementary panels (2) that they support.

  This generates a gap between the top of the post 3 and the upper ends of the respective side edges of the related panels 2. To fill this empty space, there is therefore provided a cover (18) consisting of a plate e.g. curved rectangular thermoplastic polymer. This cover (18) is fixed on the upper ends of the lateral edges 15, or on the top of the post 2 by

  any known and appropriate means, for example screws.

  It could be considered to extend the post (3), the latter may even have substantially the same length as the side edges (15) of the panels

elementary (2).

  Preferably, the upper edge (6) of each panel (2) has a rounded shape, which has appeared to be particularly suitable for limiting

  parasitic sound phenomena of diffraction.

  Advantageously, the radius of curvature of the upper section convex portion (C) is chosen so as to be the most versatile possible given the dimensions (width of the space to be phonically insulated: width of the

  roadway, railway, etc.).

  Furthermore, as already indicated above, the base (AB) of each panel (2) and of each post (3) has a straight lower section (A) extending by a median portion or section (B) formed by a concave curvature, the latter ending or extending by

  the convex upper part or section (C). See Fig. 4.

  It is understood within the meaning of the invention that the terms convexity and concavity refer to an interior constituted by the space comprising the sound sources (eg the roadway 5) and with respect to an exterior consisting of the space comprising the receivers (eg

  residents) to protect against noise pollution.

  With regard more particularly to the elementary panels (2), it should be noted that they advantageously but without limitation, a thickness which decreases from the base section (A) to the top (6) of the

convex upper part (C).

  According to another preferred geometrical characteristic of the invention, the radius of curvature RC (in meters) of the upper convex part (C) of each panel or of each post is such that:

* 1.0 .. <RC <.3,0

  * preferably 1.5 .. <RC <.2.5 RC is given here only as an example, knowing that we must also take into account the height of the elementary panels (2) which can be included, for example, between 1 and 10 meters, preferably between 2 and 5 meters, and even more preferably between 2 and 4

  meters, measured from the summit (6) to the ground.

  To fix the ideas, it can be specified that each elementary panel (2) or each post (3) has a general shape in view of assimilable profile

  roughly to that of a "tulip petal".

  With regard to the structural arrangements of the elementary panels (2), it should be noted that each panel consists of a structure or hollow shell (7) made of thermoplastic polymer material, one of the essential properties of which is to be reflective

vis-à-vis sound waves.

  On the inner face (8) of each elementary panel (2) are formed one or more compartments (9), in this case six, as shown in Figures 2, 3a and 4. Each compartment (9) advantageously having a general rectangular shape in order to

  face and intended to receive at least one- in this case one-

  sound absorbing material designated by reference (10). This absorbent material or mattress (10) is covered with at least one sheet or perforated plate (11) fixed on the

  structure (10) and closing the compartments (9).

  Advantageously, the compartments (9) of the inner face (8) of the panels (2) are arranged in the section

upper convex (C).

  Advantageously, each elementary panel (2) has a substantially rectangular shape in front view. According to variants, and without sacrificing the characteristic curvilinear profile, it is perfectly conceivable that the elementary panels (2) have other shapes in front view. For example, each panel (2) could consist of several sub-triangular elements in front view, arranged head to tail and forming a rectangle together. According to a preferred embodiment of the invention, each elementary panel (2) consists of at least two parts (7H) (top) and (7B) (bottom) assembled together by any known joining means and

  appropriate, such as bolts.

  The fact of having elementary panels (2) consisting of two pieces assemblable (7H and 7B) makes it possible to

  simply modulate the height of the screen (1).

  Advantageously, the compartments (9) of the inner face (8) of the panels (2) are arranged in the section

upper convex (C).

  Preferably, each elementary panel (2) and more particularly each constituent part (7H, 7B) of the panels (2) is obtained by rotational molding and consists of a thermoplastic polymer chosen from the group comprising: polyolefins, preferably polyethylenes ( PE), polypropylenes (PP), vinyl polychromes (PVC), polystyrenes (PE), polyacrylonitrile-butadiene-styrene (ABS), cellulose polyaceto-butyrate (CAB), poly (meth) acrylates, in particular, polymethacrylates (PMMA), ethylene vinyl polyacetates (EVA) * polyamides (PA) * polycarbonates (PC) * copolymers * and mixtures of all of these; high density PE (HDPE), low density PE (LDPE) and PVC being particularly preferred. Indeed, as shown in FIG. 4, each panel (2) or each constituent part (7H, 7B) of panel (2) is a hollow part delimited by a plastic polymer wall defining the curvilinear profile as well as on the internal face ( 8) the compartments (9) for accommodating the absorbent material (10) and, according to a preferred feature of the invention, integrated trays (13) provided on the outer face (11) intended in particular for growing plants, so to confer) this outer face (12) a "landscape" type appearance pleasing to the eye. Indeed, according to a preferred embodiment of the invention, at least a portion of the panels (2) forming the screen has on their outer faces (12) integrated trays (13) intended in particular for the cultivation of plants so as to achieve an external (12) landscape face.

Figure 4).

  The plants that can be planted in the tanks (13) of the outer face (12) of all or some of the panels (2) appear in FIG. 4 and are designated

by the reference (14).

  Rotational molding is a process for producing hollow bodies from powdered or liquid thermoplastic resin. These resins are introduced in measured quantities into a mold which is then closed. Then the mold is heated and rotated at a slow speed around two perpendicular axes. Thus, it is preferable to manufacture the hollow bodies that are the constituent parts (7H, 7B) of the elementary panel (2) or even the panel itself, in the

  where it would be in one piece.

  Conventionally, the rotational molding process comprises four main phases, namely: 1) mold loading 2) heating and rotation cycle 3) rotation and cooling cycle

4) demoulding.

  Rotomolding from thermoplastic powder requires a very fine particle size between 200 and 1200 microns. The most widely used materials are polyvinyl chloride (PVC), low density polyethylene (LDPE) high density polyethylene (HDPE) polyethylene

retified or crosslinked.

  Advantageously, the thermoplastic rotomoulding compositions comprise additives such as

  destabilizing to ultraviolet radiation.

  According to an advantageous arrangement of the invention,

  the thickness of the wall of the hollow structure (7) -

  obtained preferably by rotational molding - is included

  between 0.1 and 50 mm, preferably between 0.5 and 15 mm.

  Regarding the absorbent material (10) intended to fill the compartments (9) of the skeleton or the rotomolded hollow polymer structure (7), it is preferably made of rockwool or composites comprising recycled textile materials (eg saddlery fabric automotive) and possibly polymers

plastics and / or resins.

  This acoustic absorbent (10) can be in the form of parallelepiped plates of dimensions corresponding to those compartments (9) they fill. Without this being limiting and for fixing the ideas, it can be indicated that the thickness of absorbent material (10) is between 50 and 500 mm, preferably between 50 and 150 and more preferably

still is of the order of 100 mm.

  The density of the acoustic absorbent material (10) employed is between 50 and 500 kg / m 3, preferably between 100 and 200 kg / m 3 and more preferably between

the order of 100 kg / m3.

  According to a characteristic arrangement of the preferred embodiment, the compartment or compartments (9) of the polymer structure intended to contain or containing the acoustic absorbent (15) and are covered with at least one perforated plate (11) thus forming at least a part of the inner face (8) of each elementary panel (2), the perforations advantageously representing at least 25%, preferably at least 30% of the surface of the internal face

a sign (2,20).

  In terms of absorption, the perforation rate of the packing and containment plates of the absorbent material (10) is chosen so as to give a sufficient absorption area. In the present example, a plate is provided

  perforated (11) for each compartment (9).

  These perforated plates (11) constitute an advantageous covering protecting the absorbent material (10) against soiling. These plates may consist for example of plastic sheets or perforated metal, produced by boring or stamping or thermoforming

  to obtain protrusions, which are then topped.

  Preferably, the degree of perforation, expressed in% by surface area relative to the total surface of the inner face (8) of the panels (2) forming a screen, is 2 25%, preferably 2 30% and more preferably still

between 30 and 35%.

  To further improve the acoustic performance of the screen (1) it is advantageous, as shown in Figure 4, that the upper edge or the top (6) of each panel (2) is rounded and preferably comprises at least one acoustic absorbing material, in this case the absorbent material (10), so as to limit the phenomenon of

acoustic diffraction.

  It should also be noted that each elementary panel (2) of the screen (1) comprises two lateral edges (15), each of which cooperates with a junction and support pole (3). To this end, this lateral edge (15) has, relative to said post (3), either a male conformation or a female conformation, the latter being preferred since it allows

  at least partially mask the male pole element (3).

  In the preferred embodiment shown in FIGS. 2 to 4, each lateral edge (15) has a female configuration of generally "U" -shaped shape in right cross-section. Such a "U" shape exists on at least a portion of each lateral edge

(15) concerned.

  With regard to the junction and support poles (3), it is provided according to a preferred characteristic of the screen according to the invention that each support and joining post (3) is preferably made of metal and has a substantially general form of "H" in

cross section right.

  These junction posts (3), which are preferably made of metal and which are obtained according to the PRS technique (welded reconstituted profile), offer, thanks to their "H" shape, two symmetrical housings in which the lateral edges (15) of the contiguous panels (2) are intended for

to be nested.

  These posts (3) for support and maintenance, curvilinear profile similar to that of the panels (2), each comprise at their base a plate (16) preferably metal, for anchoring on the base plates (4) preferably of concrete. The plates (16) are secured to these concrete bases (4) by screwing, pegging or pegging, e.g. In the example shown in FIG.

  (1) consists of panels (2) aligned or coplanar.

  But it goes without saying that the screen according to the invention can adapt to the curvilinear forms (bends) of the site on which it is installed. To this end, the panels (2) contiguous can be angularly offset the eye relative to the others. In this case, the posts (3) in "H" put

  between these panels (2), have wings -

  no longer coplanar - but angularly shifted, so as to define an angular sector corresponding to that which one wishes to put in place between the 2

party signs considered.

  Advantageously, at least one O-ring (17) is disposed between each support and joining pole (3) and the parts of the two adjacent panels (2) supported by

this post (3).

  The elementary panels (2) and the supporting and connecting posts (3) have a shape and a constitution designed and selected so as to mechanically withstand the normal stresses to which the screen (1) can normally be subjected on the sites of use. In particular, the screen (1) has good resistance to

  wind, shocks, erosion, corrosion (strong winds).

  This acoustic screen (1) also has the advantage of being easily maintained. the cleaning of the hollow plastic structure is relatively easy to perform. Similarly, the absorbent material (10) protected can also be washed easily. To further facilitate its maintenance, it can be planned to apply anti-graffiti treatment while

actually compatible.

  Mounting this screen is easy to do. First, the civil engineering works are limited since they simply consist of manufacturing concrete bases (4) on which are fixed the posts (3). In addition, it is possible to engage the elementary panels (2) either from above or laterally in the complementary housing of the posts (3). This gives some adaptability to the topography of the site of

screen construction.

  The nature of the materials preferably implemented

  work is not a source of ecological problems.

  Furthermore, the screen (1) according to the invention has an aesthetic and original exterior appearance. In this respect, since thermoplastic polymers are used for the hollow structure (7), it is quite easy to carry out various colorations in the mass at will. This can only enrich the aesthetic advantages already provided by the shape and the

  possibility to realize an external face (12) landscape.

  Finally and above all, the acoustic performance of the screen (1) according to the invention are quite satisfactory. Indeed, it seems possible to reach

  attenuation indices R 2 35 dB (A).

  Expressed otherwise, the screen (1) according to the invention has an acoustic absorption capacity which can rise

at least up to 0.90.

  This screen is therefore quite effective as regards the protection of the receivers with respect to polluting sound sources, automotive, railway,

  aerial, industrial or other.

  Another asset to credit to the screen according to

  the invention is due to its reasonable cost price.

It is also can messy.

  In addition, it is adaptable to multiple

  lane configurations.

  FIGS. 5a and 5b, correspond to an alternative embodiment in which the lateral edges 150 of the elementary panels (20) constituting the screen (10) according to the invention, have a male-type conformation, whereas the poles (30) ) of support and junction are

of the female type.

  In these FIGS. 5a and 5b, the elements common with those represented in FIGS. 2 to 4 have been designated by the same references to which the numeral 0 has been added. It therefore appears that the posts (30) always have an "H" conformation. in the right cross section as in the preferred embodiment, but in this variant, the crossbar of the "H" has a dimension greater than the thickness of the side edge (150) of the elementary panel (20). Hence it follows that this side edge (150) can be engaged and housed in one of two gutters formed by half of the pole (30). The other symmetrical gutter of the same pole (30) is intended to receive the lateral edge (150) of the adjacent elementary panel (20). An O-ring (170) seals

  between the side edge (150) and the post (30).

  Each side edge (150) and separated from the rest of the panel (20) by a shoulder (16) on each inner (10) and outer (120). The thickness of each shoulder (16) substantially corresponds to the thickness of the wings of the post (30) at "H", so that the external faces of said post (30) are substantially in the same plane as the

  inner (80) and outer (120) faces respectively.

  The panel (20) comprises the same elements as the panel (2) including the perforated plates (110) disposed on the inner face (80), the top (60) and the outer face (120). The post (30) comprises a plate (160) for fixing it to a foundation base

not shown.

  According to another of its objects, the present invention relates to an elementary panel 5, 20) and / or a post (3, 30) of support and junction, in particular of the type of those described above, and intended to be used for the

  mounting of an acoustic screen (1) as defined above.

  According to one variant, the modular panels (2, 20) forming the noise barrier (1,10) of the "tulip" type may comprise photovoltaic cells intended to

  supply signal lamps.

  It goes without saying that any other signaling element that does not require power supply can also equip the panels forming the screen according to the invention. By way of example, mention may be made of bands

  reflective to light (reflex reflectors).

  According to another variant, the screen can be mounted

on a concrete parapet.

Claims (10)

  An acoustic screen (1,10) comprising a plurality of elementary panels (2, 20) of curvilinear profile, juxtaposed and supported by connecting posts (3, 30) arranged between these panels (2, 20), characterized: each panel (2, 20) and each post (3, 30) having a base (AB) extended by a convex upper part (C), this base (AB) breaking with the convexity of the latter (C); and in that each panel (2, 20) comprises: on the one hand, a structure (7, 70), preferably hollow, of thermoplastic polymer material, and, on the other hand, at least one material (10); ) acoustic absorbent, preferably disposed on the inner face (8,80) of the panel and more preferably still in at least one compartment (9) arranged in the polymer structure (7.70).   2 - Screen according to claim 1 characterized in that each panel (2,20) has a shape substantially rectangular in plan view.   3 - Screen according to claim 1 or claim 2 characterized in that the structure - preferably hollow - each panel (2,20) is obtained by rotational molding and is constituted by a thermoplastic polymer selected from the group comprising: * polyolefins , preferably polyethylenes (PE), polypropylenes (PP), polychrome vinyls   (PVC), polystyrenes (PE), polyacrylonitrile   butadiene-styrene (ABS), cellulose polyaceto-butyrate (CAB), poly (meth) acrylates, in particular, polymethacrylates (PMMA), ethylene vinyl polyacetates (EVA) * polyamides (PA) * polycarbonates (PC) * copolymers * and mixtures thereof; High density PE (HDPE), low density PE (LDPE) and PVC being particularly preferred   4 - Screen according to any one of the claims   1 to 3 characterized in that the acoustic absorbing material is selected from the group consisting of: * rock wool, * lignocellulosic materials, * textile materials, * composites.   Screen according to any one of the claims   1 to 4 characterized in that the compartment or compartments (9) of the polymeric structure are intended to contain or contain the acoustic absorbent and are covered with at least one perforated plate (11, 110) thereby forming at least part of the face internal portion (8, 80) of each elementary panel (2, 20), the perforations advantageously representing at least 25%, preferably at least 30% of the surface of the inner face of a panel (2,20).   6 - Screen according to any one of the claims   1 to 5 characterized in that each panel (2, 20) consists of at least two assembled parts (7H, 7B) between they.   7 - Screen according to any one of the claims   1 to 6 characterized in that each lateral edge (15, 150) of a panel cooperating with a pole, has, relative to said post, a male conformation, a female conformation, the latter being preferred so as to mask at least partially the male pole element (3), the female configuration of the lateral edges (15) substantially "U" in right cross section being particularly preferred.   8 - Screen according to any one of the claims   1 to 7 characterized in that each supporting and joining post is preferably of metal and has substantially a shape of "H" in right cross section (3, 30)   9 - Screen according to any one of the claims   1 to 8 characterized in that the radius of curvature (RC) of the convex part of each panel or of each post is such that: * 1.0 <RC <3.0   * Preferably 1.5 <RC <2.5 10 - Screen according to any one of   Claims 1 to 9, characterized in that the base (AB) of   each panel (2, 20) and each post (3, 30) has an inner right-angled section extending through a medial portion (or section) B formed by a concave curvature, the latter being extended by the convex upper part (or section) C. 11 - Screen according to any of the   Claims 1 to 10 characterized in that at least one   seal is disposed between each support and joint post and the portions of the two adjacent panels (2, 20) supported by this post (3,30).   12 - Screen according to any one of   Claims 1 to 11 characterized in that the edge   upper (6,60) of each panel (2,20) is rounded and, preferably, comprises at least one acoustic absorbing material so as to limit the acoustic diffraction phenomenon. 13 - Screen according to any one of   Claims 1 to 12, characterized in that at least one   part of the panels (2, 20) has on their outer face (12, 120) integrated trays (13) intended in particular for growing plants (14) so as to produce a face external "landscape".   14 - elementary panel and / or support and joining pole, intended to be used for mounting an acoustic screen (1,10) as defined in at least   one of the preceding claims.