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TEXT OF THE DESCRIPTION

Field of the invention

The present invention relates to modular elements for constructions. The invention has been developed with particular reference to modular elements for erecting structures, such as transparent coverings, for example geodesic domes or the like.

Prior art and general technical problem

In the construction of transparent structures, i.e., ones that allow passage of light rays coming from outside, one of the most recurrent problems that designers find themselves having to tackle is the reduction of heat exchange (whether of a conductive, convective, or radiant type) between the structure and the external environment, the purpose being to guarantee more favourable climatic conditions within the structure, especially in the case of buildings that are to house people in order to enable less stringent requirements of performance for the air-conditioning system inside the structure.

Currently known solutions are generally characterized by a considerable constructional complexity that is liable to require first of all highly specialized staff for installation and, clearly, is liable to result in a decidedly high final cost of erection of the structure. Furthermore, the efficiency of known solutions as regards containment of heat exchange certainly leaves room for improvement, above all in the light of recent dispositions in the sector of energy efficiency for new buildings.

Object of the invention

The object of the invention is to solve the technical problems mentioned previously. In particular, the object of the invention is to provide a modular element for constructions, in particular for erecting structures such as transparent coverings, that will present a high degree of constructional simplicity and high capacity of thermal insulation in regard to the external environment.

Summary of the invention

The object of the invention is achieved by a modular element for constructions having the characteristics forming the subject of one or more of the ensuing claims, which form an integral part of the technical disclosure provided herein in relation to the invention .

In particular, the object of the invention is achieved by a modular element for constructions including :

- a perimeter frame;

- a mesh structure coupled to said perimeter frame; and

- a covering sheath, which covers said perimeter frame and said mesh structure,

wherein vacuum is applied within said covering sheath.

Brief description of the drawings

The invention will now be described with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:

Figure 1 is a perspective view of a preferred embodiment of the invention;

Figure 2 is a cross-sectional view according to the trace II-II of Figure 1;

Figure 3 includes a first portion A consisting of a top plan view according to the arrow III of Figure 1 and a second portion B illustrating a top schematic plan view corresponding to that of the portion A but representing an advantageous aspect of the invention;

Figures 4 and 5 are similar to Figure 3 but refer to second and third preferred embodiments;

Figure 6 is a cross-sectional view of a different implementation of the embodiments represented in the previous figures;

Figures 7, 8, and 9 are schematic views (in cross section as regards Figures 7 and 8 and exploded as regards Figure 9) regarding advantageous constructional variants of the embodiments represented in the previous figures;

Figure 10 is a top plan view of yet a further embodiment of the invention; and

Figures 11 and 12 are cross-sectional views according to the lines XI-XI and XII-XII, respectively, of a component of the modular element of Figure 10 and of the complete modular element of Figure 10.

Detailed description of preferred embodiments

In Figure 1 the reference number 1 designates a modular element for constructions according to a first preferred embodiment of the invention. The modular element 1 includes a perimeter frame 2, a mesh structure 4 coupled to the perimeter frame 2 and extending therein, and a covering sheath 6 (in what follows, for brevity, frequently referred to merely as "sheath"), which covers it completely; i.e., it covers the perimeter frame and the mesh structure.

In greater detail, the perimeter frame 2 has a preferably polygonal shape, which in the preferred embodiment illustrated herein corresponds to a triangle and includes a first side 8, a second side 10, and a third side 12 of identical length (the shape is hence that of an equilateral triangle) . Of course, the length of the sides can be varied according to the needs (so that it will be possible to have isosceles or scalene triangular geometries), in particular, according to the geometry of the structure that is to be obtained.

With reference to Figures 1 and 2, each side includes a pair of metal profiles 8A, 10A, 12A, set between which is an insert 14 made of insulating material (for example, plastic material or ceramic material) that develops throughout the length of each side and consequently substantially along the entire perimeter of the frame 2, providing a thermal interruption in the perimeter frame 2 that is designed to limit conductive heat exchange.

The sides of the perimeter frame 2 are preferentially joined together by means of corner joining elements designated by the reference number 16. In some variants, it is possible to provide a direct connection between the metal profiles 8A, 10A, 12A constituting each side, for example a weld. In this case, the insert 14 can be obtained as a continuous element on the three sides of the perimeter frame 2.

With reference to Figures 1, 2, and 3A, in a preferred embodiment the mesh structure 4 includes a pair of nets 4' of wire-like elements, preferentially made of metal material or of plastic material, tensioned between the sides of the perimeter frame 2 in the region corresponding to the opening identified by the perimeter frame itself. In the preferred embodiment represented in Figures 1 to 3, each net 4' of the aforementioned pair of nets is set at opposite axial ends of the perimeter frame 2, i.e., at the opposite ends of the opening defined by the perimeter frame itself. The axis XI of Figures 1, 2, and 3 will be assumed as a reference axis.

Each net 4' is obtained in a way at least roughly resembling a tennis racket: each net includes a plurality of wire-like elements that are passed through the walls of the perimeter frame (see, for example, Figure 2) according to a generally serpentine (or fret ^¬ like) path. In greater detail, with reference to Figure 3A, the net 4' is defined by wire-like elements tensioned between two sides and parallel to the remaining side of the perimeter frame 2 so as to define a plurality of triangular meshes 4B. This result can be achieved in various ways.

In some variants, it is possible to provide a single wire-like element 4A of considerable length that is passed through the walls of the frame sequentially following paths parallel to each side (for example, a first serpentine path is imparted with orientation of the rectilinear stretches parallel to the side 8, a second serpentine path is imparted with orientation of the rectilinear stretches parallel to the side 10, and a third serpentine path is imparted with orientation of the rectilinear stretches parallel to the side 12) .

In other variants, it is possible to use three distinct wire-like elements 4A, each associated to a serpentine path with rectilinear stretches parallel to a single side.

In yet further variants, it is possible to provide a greater number of wire-like elements: in this case, each wire-like element tensioned between two sides of the perimeter frame 2 with orientation parallel to the remaining side will preferentially be an independent wire-like element.

The sheath 6 is preferentially provided as an envelope made of strong polymeric material, for example ETFE (ethylene tetrafluoro ethylene), and transparent. In the preferred embodiment illustrated herein the shape of the sheath 6 at least roughly resembles that of a bag housed in which is the perimeter frame 2 with the pair of nets defining the mesh structure 4. Vacuum is applied inside the sheath 6 in such a way that this adheres tigthly to the frame 2 and to the nets 4' of the mesh structure 4. It should be noted that application of vacuum enables a stable shape to be bestowed on the structure: the various profiles of the perimeter frame and the layer of insulating material are fixed in position by contraction of the sheath 6 on account of the vacuum applied therein, which prevents, among other things, the need to provide mechanical connections between the metal profiles and the layer of insulating material that would inevitably come to form a thermal bridge.

For this purpose, the sheath 6 may be provided with a valve 18 (represented schematically in Figure 3A) that can be connected to a vacuum pump for creating vacuum therein. For this purpose, it is clearly necessary for the sheath 6 to be impermeable to air or, in the case where the material of which it is made is not impermeable, for this material to be rendered such.

Further advantageous aspects of the modular element according to the invention will now be illustrated .

With reference to Figure 1, a perimeter sheath 20 of flexible material (for example, an elastomer) is applied to the perimeter frame 2 on top of the sheath 6 so as to protect the latter from any possible tears that might jeopardize the vacuum-tightness capacity thereof. In the embodiment illustrated in Figures 1 and 2, the perimeter sheath 20 has a substantially C-shaped cross section so as to fit on the perimeter frame and be anchored firmly thereto, exploiting the fact that the nets 4' constituting the mesh structure 4 are preferably set in a position slightly underneath the surface defined by the perimeter frame 2.

With reference to Figure 3B, advantageously the modular element 1 includes one or more reinforcement elements configured for maintaining the geometry of the frame 2 unaltered under load. In the preferred embodiment represented in Figures 1 to 3, the modular element 1 includes three reinforcement elements designated by the reference numbers 22, 24, 26, each basically configured as a strut. Each of the reinforcement elements 22, 24, 26 is connected to the perimeter frame 2 substantially at the midpoint of two adjacent sides, between which it extends. Deriving from this is the fact that the arrangement of the reinforcement elements 22, 24, 26 is itself triangular and moreover, in this embodiment in which an equilateral perimeter frame is provided, also defines an equilateral triangle.

With reference to Figure 2, a layer 28 of reflecting material is moreover advantageously applied within the frame 2, here in particular on the reinforcement elements 22, 24, 26 (but could be simply fixed to the frame 2 without the support of the reinforcement elements 22, 24, 26) . Preferentially, the layer 28 is constituted by a material having the capability of reflecting visible, ultraviolet, and infrared light of a fixed type or else a variable type that can be modulated as desired, for example by applying of a variable voltage at its ends.

In some variants, it is finally possible to provide the insert of insulating material 14 as a basically discontinuous structure, for example by means of a plurality of inserts of plastic or ceramic material set between the profiles 8A, 10A, 12A alternating with which are free spaces. It should moreover be noted that the performance in terms of insulation with respect to conductive heat exchange is in any case kept at a satisfactory level since at the moment of application of vacuum within the sheath 6 also in the free spaces vacuum is set up, which inhibits at least conductive and convective heat exchange .

Operation of the modular element 1 is described in what follows.

The modular element 1 is configured for the creation, precisely according to criteria of modularity, of whatever shell structure the shape of which is suited, so to speak, to discretization by means of a plurality of structural elements corresponding to the element 1.

A plurality of elements 1 is joined to form the aforesaid structure: for this purpose, for mutual connection it is possible to envisage, in the case of structures of modest dimensions, joining elements to be used together with the elements 1 that can be installed astride of a pair of adjacent sides of the perimeter frames of two contiguous elements 1 so as to fix the position thereof. In this case, the elements 1 are assigned a load-bearing function.

For structures of larger size, there may be envisaged creation of a skeleton with lattice structure positioned in the meshes of which are the modular elements 1. Of course, the dimensions of the modular elements 1 may be adapted and modulated according to the specific needs. In these other cases, the elements 1 are assigned a semi-load-bearing or non-load-bearing function, according to the design.

Whatever the construction system chosen, it should be noted how the provision of the perimeter sheath 20 will prevent tearing of the sheath 6 and consequent loss of vacuum inside it. Maintenance of vacuum is in fact essential in order to limit as much as possible convective heat exchange, and in particular entry of a massive flow of heat, in conditions of exposure to sunlight, that heats the air inside the structure. This considerably contributes to raising the efficiency of the structure obtained with the elements 1, in so far as it enables, given the same external climatic conditions, a milder temperature of the air inside. This, in ultimate analysis, generally enables a less stringent sizing of the air-treatment and conditioning system possibly present in the structure.

The conductive heat exchange between the side of the elements 1 directly exposed to solar radiation and the side facing the inside of the structure is moreover limited by the presence of the inserts 14 made of insulating material, which function as thermal interruption in the element 1, in the first place limiting conductive heat exchange.

The person skilled in the art will appreciate, however, that, in presence of the external atmospheric pressure, maintenance without alterations of the geometry of the elements 1 is an extremely burdensome task: the presence of vacuum within the sheath 6 constitutes a natural predisposition to collapse of the element 1. For this purpose, the mesh structure 4, in particular the pair of nets 4' that constitute it, performs a very important role. In the first place, each of the nets 4' offers an abutment surface to the sheath 6 when vacuum is applied thereto. This provides first of all a certain regularity on the structure of the element 1 itself in so far as it prevents the sheath 6 from assuming a conformation with creases and folds of every kind, as instead would happen if the sheath 6 extended over the perimeter frame 20 without any support at the opening defined therein.

By so doing, as may be seen on the other hand in Figure 2, a very regular configuration is obtained defined in which is a sufficiently regular volume comprised between the two nets within which vacuum is obtained .

In the second place, each net 4' operates substantially as a tensile structure: the stress that is set up in the wire-like elements 4A contains deformation of the sheath 6 caused by application of vacuum, but tends to subject the perimeter frame to deformation like a beam loaded from outside inwards. It should moreover be noted that preferably the wire-like elements 4A are tensioned between the sides of the perimeter frame by imparting thereon a non-zero value of axial tensile stress so as to pre-tension the net 4' limiting inflection thereof in the midpoint, but increasing the load on the frame.

Given moreover that generally the deformation of each side of the triangle has a maximum at the midpoint of each side, the provision of the reinforcement elements 22, 24, 26, the ends of which - as has already been said - are precisely positioned at the midpoint of two adjacent sides, will likewise make a decidedly significant contribution in maintaining the shape of the perimeter frame 2 under load.

The aspect of maintenance of the geometry of the elements 1 under load is hence important at least for two reasons :

in the first place, and this applies in particular for the structures in which the elements 1 are load-bearing, i.e., are not inserted within a supporting lattice structure, maintenance of the shape of the structural elements 1 renders more unlikely the event of a structural collapse caused by onset of excessive stresses within the structure;

- in the second place, irrespective of the type of construction and of the size of the structure, maintenance of the shape set down in the design stage ensures minimization of the area of the gaps between contiguous elements 1 into which there may penetrate air from outside giving rise to a heat exchange of a convective type with the structure constituted by the elements 1 themselves. For this purpose, as will be seen in what follows, it is possible to limit the width of the gaps between the frames by applying perimeter shells (SHL in Figures 13 and 14), which are brought into contact when a number of modular elements are set side by side and installed with sealing of the gaps between them. The shells can moreover function as "thermal-expansion joints", remaining undeformed and hence acting as a seal, whereas the frame covered therewith may even undergo deformation with an acceptable inflection.

Provision of the layer 28 is finally very interesting for all those applications where there is the need to vary the brightness of the environments inside the structure constituted by the elements 1 without resorting to mobile elements such as roller shutters or blinds.

Application of a variable voltage at the ends of the layer of material 28 results in a modulation of the refractive index of the layer 28, which consequently will determine the amount of light rays that will be refracted or reflected by the layer 28 itself.

For example, in structures located in environments continuously exposed to sunlight and characterized by a high irradiated energy, modulation of the properties of transmission of sunlight of the elements 1 through the layer 28 enables radiant heat exchange (i.e., heat exchange by irradiation) to be kept under control, which otherwise would not be controllable in any other way. In fact, if setting-up of vacuum within the sheath 6 massively limits convective heat exchange, as is known radiant heat exchange is irrespective of the presence of a medium for carrying the thermal flow and can consequently take place also in vacuum. Only an effective action of shielding such as the one exerted via the element 28 enables limitation of the thermal flow entering the structure by irradiation.

The layer 28 (or possibly a second layer parallel thereto) can be configured in addition or as an alternative for modifying the spectrum of the incident light radiation; i.e., in this case the layer would enable spectral concentration in frequency bands of particular importance for the elements contained within a structure of which it forms a modular element (as will emerge more clearly from what follows) . For example, in the case of plants that carry out photosynthesis, the layer 28 can be configured for selecting the frequencies of visible light corresponding to the colours blue and red, in so far as, for example, it is demonstrated that the frequencies corresponding to green are less used by plants in the process of photosynthesis.

In the case where both of the properties are to coexist (spectral modification and variable reflection) it is preferable to double the layer 28, as already mentioned, into a first layer with variable properties of reflection of visible, ultraviolet, and infrared light, and a second layer that is able to make a spectral modification.

Finally, it is preferable for some of the elements

1 that make up the structure to be installed so as to enable oscillation thereof about an axis in order to render the structure itself openable at one of the elements 1, favouring natural circulation of the air. This is desirable in all the conditions in which a rapid air change is necessary within the structure itself .

A second embodiment of a modular element for constructions is designated by the reference number 100 in Figure 4A. The element 100 is substantially identical to the element 1, except for some constructional peculiarities and as regards the shape of the perimeter frame 2, once again polygonal, but hexagonal .

The modular element 100 includes a perimeter frame

102, a mesh structure 104 coupled to the perimeter frame 102 and extending inside it, and a sheath 106 that covers it completely, i.e., covers the perimeter frame and the mesh structure.

In greater detail, the perimeter frame 102 has a regular hexagonal shape, i.e., including six sides of identical length. The structure of each side is preferably identical to the one illustrated in Figure 2 for the sides 8, 10, 12.

The profiles constituting each side of the perimeter frame 102 are preferentially joined together by means of corner joining elements similar to the elements 16 (not visible in Figure 4A) . In some variants, it is possible to provide a direct connection between the profiles constituting each side, for example a weld.

In the preferred embodiment represented in Figure 4A the mesh structure 104 is obtained as a pair of nets 104' of wire-like elements 104A, preferentially made of metal material or plastic material, tensioned between the sides of the perimeter frame 102 in the region corresponding to the opening identified by the perimeter frame itself.

In this embodiment, each net 104' of the aforementioned pair is set at opposite axial ends of the perimeter frame 102, i.e., at the opposite ends of the opening defined by the perimeter frame itself. The axis X100 of Figure 4 is assumed as reference axis. The modalities of creation of the nets 104', where not manifestly incompatible, are the same as those already described in detail as regards the element 1. However, in this case there is a co-presence of meshes 104B shaped like equilateral triangles, rhomboidal meshes 104C, trapezoidal meshes 104D, and even meshes shaped like right triangles. The reason for this is that the wire-like elements 104A are not tensioned extendning between contiguous sides of the perimeter frame 102 but are tensioned extendning between pairs of parallel sides .

The sheath 106 is made in a way similar to the sheath 6 and also this is provided with a valve 118 for connection to a vacuum pump. In this way, it is possible to set up vacuum therein, so that the sheath can adhere tigthly to the frame 102 and to the nets 104' of the mesh structure 104, fixing the geometry of the element 100, as described previously as regards the element 1

Further advantageous aspects of the modular element 100 according to the invention will now be illustrated.

Like the element 1, a perimeter sheath 120 of flexible material (for example an elastomer) is applied to the perimeter frame 102 on top of the sheath 106 so as to protect the latter from any possible tears that might jeopardize the vacuum-tightness capacity thereof.

With reference to Figure 4B, advantageously the modular element 100 includes one or more reinforcement elements configured for maintaining the geometry of the frame 102 unaltered under load.

In the preferred embodiment represented in Figure 4, the modular element 100 includes three reinforcement elements designated by the reference numbers 122, 124, 126, each basically configured as a strut. Each of the reinforcement elements 122, 124, 126 is connected to the perimeter frame 102 substantially at the midpoint of two parallel sides, between which it extends.

Furthermore, inside the sheath 106 there can be set a layer of reflecting material similar to the layer 28, with the same modalities and the same function.

Operation of the modular element 100 is substantially identical to what has already been described as regards the element 1.

A third embodiment of a modular element for constructions is designated by the reference number 200 in Figure 5A. The element 200 is substantially identical to the elements 1 and 100, but for some constructional peculiarities and for the shape of the perimeter frame, once again polygonal, but rectangular.

The modular element 200 includes a perimeter frame 202, a mesh structure 204 coupled to the perimeter frame 202 and extending therein, and a sheath 206 that covers it completely; i.e., it covers the perimeter frame and the mesh structure. The structure of each side is preferably identical to that illustrated in Figure 2 for the sides 8, 10, 12.

The profiles constituting each side of the perimeter frame 202 are preferentially connected together by means of corner joining elements similar to the elements 16 (not visible in Figure 4A) . In some variants, it is possible to provide a direct connection between the profiles constituting each side, for example a weld.

In the preferred embodiment represented in Figure 5A, the mesh structure 204 is obtained as a pair of nets 204' of wire-like elements, preferentially made of metal material or plastic material, tensioned between the sides of the perimeter frame 202 in the region corresponding to the opening identified by the perimeter frame itself.

In the above embodiment, each net of the aforementioned pair is set at opposite axial ends of the perimeter frame 202, i.e., at the opposite ends of the opening defined by the perimeter frame itself. The axis X200 of Figure 5 is assumed as reference axis. The modalities of creation of the nets 204', where not manifestly incompatible, are the same as those already described in detail as regards the element 1. However, in this case the meshes (designated by the reference number 204B) have a quadrangular shape. Like the element 100, the wire-like elements 204A are tensioned extendning between pairs of parallel sides of the perimeter frame 202.

The sheath 206 is made in a way similar to the sheath 6 and also this is provided with a valve 218 for connection to a vacuum pump. In this way, it is possible to set up vacuum therein so that it can adhere tightly to the frame 202 and to the nets 204' of the mesh structure 204 fixing the geometry of the element 200 as described previously as regards the element 1.

Further advantageous aspects of the modular element 200 according to the invention will now be illustrated .

Like the elements 1 and 100, a perimeter sheath 220 made of flexible material (for example, an elastomer) is applied to the perimeter frame 202 on top of the sheath 206 so as to protect the latter from possible tears that might jeopardize the vacuum- tightness capacity thereof.

With reference to Figure 5B, advantageously the modular element 200 includes one or more reinforcement elements configured for maintaining the geometry of the frame 202 unaltered under load.

In the preferred embodiment represented in Figure 4, the modular element 200 includes two reinforcement elements designated by the reference numbers 222, 224, each basically configured as a strut. Each of the reinforcement elements 222, 224 is connected to the perimeter frame 202 substantially at the midpoint of two parallel sides, between which it extends.

Furthermore, within the sheath 206 there can be set a layer of reflecting material similar to the layer 28, with the same modalities and the same function.

Operation of the modular element 200 is substantially identical to what has already been described as regards the element 1 and the element 100.

Of course, it is possible to envisage other polygonal shapes for the perimeter frame, for example a pentagonal shape. However, it is possible also to make the perimeter frame of a circular shape or with rectilinear stretches alternating with circular stretches. In this case any structure made up of the elements according to the invention will have to include modular elements of different shapes joined together in order to provide a coupling that makes it possible to follow the shape desired for the structure.

Further advantageous variants as regards design and construction of the elements 1, 100, 200 according to the invention are represented in Figures 6 to 8.

With reference to Figure 6, which moreover illustrates the sheath 6 prior to application of vacuum, the mesh structure 4, 104, 204 can be obtained using, instead of the wire-like elements tensioned extendning between two sides of the perimeter frame, prefabricated nets 4*, 104*, 204* (for example, but not necessarily, electro-welded metal nets or nets of polymeric material), in order to render the manufacturing of the modular element forming the subject of the invention yet faster, and even more economically advantageous. As may be seen in Figure 6, in some variants a small auxiliary frame may be provided, for example obtained with extruded profiles of plastic material or profiles of bent sheet metal, designated by the reference number 4''. The prefabricated net can be applied on the auxiliary frame 4'', which can then be applied on the perimeter frame 2, 102, 202. It is also possible to use the auxiliary frame 4'' in combination with the wire-like elements described previously. The net constituting the mesh structure would be tensioned and interwoven directly on the frame 4'' and then applied on the perimeter frame 2, 102, 202.

With reference to Figure 7, the modalities of construction of the perimeter frame may moreover even envisage, so to speak, reversal of the arrangement of layers already illustrated. In particular, instead of the insert 14, a core 14B of each side of the perimeter frame 2, 102, 202 may be obtained with a profile of metal material, which among other things favours ease of coupling with the possible reinforcement elements (the element 22 is illustrated by way of example in the figure) , which may likewise be made of metal material and welded or connected in some other way to the core itself .

At the opposite axial ends of the perimeter frame, where the nets constituting the mesh structure 4, 104, 204 are applied, each side of the perimeter frame may be constituted by a profile of thermally insulating material 14A coupled to the metal core 14B to define the side itself.

In this variant the wire-like elements that provide the mesh structure can traverse the perimeter frame (top portion of Figure 7) or, in the case where they are made of plastic material, be thermally welded to the insulating material of the perimeter frame 2 (or again be made integrally therewith) .

With reference to Figure 8, the cross section of the sides of the perimeter frame may be varied with respect to the rectangular shape illustrated. It is possible, for example, to bestow on the cross section a substantially oval or ovoidal shape, irrespective of whether it is chosen to make the perimeter frame with a layered structure of the metal-insulator-metal type (Figure 8A, similar to the one represented in Figures 1 to 6) or insulator-metal-insulator type (Figure 8B, similar to the one represented in Figure 7) .

With reference to Figure 9, in the case where the construction chosen for the sides of the perimeter frame 2 is of the metal-insulator-metal type (thus using a definition already introduced previously) a set of reinforcement elements 22, 24, 26 may be provided for each metal layer. In other words, for each set of profiles 8A, 10A, 12A a set of reinforcement elements 22, 24, 26 may be provided, in this way leaving the insert of insulating material 14 (here shown of a continuous type; of course, a segmented embodiment is possible with inserts of ceramic or plastic material as described previously) without them. The nets constituting the mesh structure 4 may either be of the type tensioned on the profiles 8A, 10A, 12A (set of profiles arranged on top in Figure 9) or of the prefabricated type coupled to the auxiliary frame 4'' (set of profiles arranged at the bottom in Figure 9) . What is illustrated in Figure 9 of course also applies to any geometry of the modular element represented in the disclosure, hence including the elements 100, 200. As further variants, even though this may entail a slight increase in costs, the perimeter frame may entirely be made of composite material (i.e., without the layered structure represented in the foregoing description) , which may be chosen so as to satisfy both the requirements of performance in terms of thermal insulation and the requirements of structural strength. A preferred choice in this sense is that of composite materials with polymeric matrix or ceramic matrix.

As regards a possible method of construction of the modular elements 1, 100, 200 reference may be made, by way of example, to the brief ensuing description.

Each of the modular elements 1, 100, 200 can be produced by starting the assembly thereof from the innermost layer. In the case of metal-insulator-metal layering, the starting point is the insulator layer, in the case of insulator-metal-insulator layering the starting point is the metal layer. In either case, except in the event where an embodiment of the type illustrated in Figure 9 is adopted, also the ensemble of the reinforcement elements must be provided. Next, the further layers of the perimeter frame are assembled, taking care to provide an additional constraint at the interface with the reinforcement elements so as to enable transmission of forces between the latter and the layers that surround the central layer of the perimeter frame (in the case of an embodiment of the type illustrated in Figure 9 it will be necessary to do the same so as to ensure transmission of forces with the intermediate layer) .

The next step is assembly of the nets 4*, 104*, 204* carried by the auxiliary frames 4'', in the case where these have not already been provided by means of wire-like elements tensioned over the profiles 8A, 10A, 12A. Then, the sheath 6, 106, 206 may be provided in situ by welding together along a path that depends upon the geometry of the modular element that it is intended to obtain (polygonal, number of sides, etc.) by means of a welder for plastic materials. In this step, it will be necessary to pay attention to creation of a receptacle for the valve 18 118, 218 and to the possible creation of passages for the air in the profiles of the perimeter frame that will enable evacuation of the air that remains trapped within the narrower gaps (this applies in particular to the case where the profiles 8A, 10A, 12A are made with a hollow section, as an alternative to the full cross section represented in the figures annexed to the present description) .

The next step consists in application of the perimeter sheath 20, 120, 220 and in application of vacuum within the sheath 6, 106, 206, which will then have to be sealed so as to prevent any intrusion of air therein. In preparation of this step, it is moreover possible to apply one or more layers of insulating tape in selected areas of the perimeter frame 2, 102, 202 during assemblage of the various layers that make it up so as to fix preliminarily the geometry of the element, which is then completed in a definitive way with application of vacuum within the sheath 6, 106, 206.

Finally, it should be noted, as yet a further variant, that it is possible to make the auxiliary frames 4'' (where used) with a certain deformability and with non-pretensioned wire-like elements. In this way, the auxiliary frames 4'' could be themselves "fitted" on the perimeter frame 2, 102, 202, and tensioning of the wire-like elements 4A, 104A, 204A could be carried out at the moment of fitting of the frames 4'' on the perimeter frame 2, 102, 202, or at the moment of coupling of the perimeter sheath 20, 120, 220, or at the moment of application of vacuum in the sheath 6, 106, 206, or again in a distributed way in one or more of the aforementioned steps.

When the structure made up of modular elements according to the invention has been erected, any possible air infiltration can be locally compensated for by temporarily connecting the modular element involved in the phenomenon to a vacuum pump. In the case where, instead, it is envisaged that, for example, on account of particularly burdensome weather or operating conditions, a number of modular elements can be involved in phenomena of air infiltration, a network of small pipes can be provided that reach the various modular elements (in particular, the valves of each of them) and branch off from a header, which is in turn connected to a vacuum pump of large dimensions, for example supplied by means of electrical energy converted by photovoltaic panels arranged on the structure itself.

Of course, the details of construction and the embodiments may vary widely with respect to what has been described and illustrated herein, without thereby departing from the sphere of protection of the present invention, as defined by the annexed claims.

In this connection, with reference to Figures 10 to 12, a further embodiment of the modular element according to the invention is designated by the reference number 300.

The modular element 300 includes a perimeter frame

302, a mesh structure 304 coupled to the perimeter frame 2 and extending therein, and a covering sheath 306 (which in what follows will be simply referred to as "sheath") that covers it completely, i.e., that covers the perimeter frame and the mesh structure. In greater detail, the perimeter frame 302 in this embodiment is square-shaped, but the person skilled in the art will appreciate that the element 300 may be obtained with any polygonal shape.

In the preferred embodiment illustrated herein, the perimeter frame 302 includes a first side 308, a second side 310, a third side 312, and a fourth side 314 of identical length. Of course, the length of the sides may be varied according to the geometry of the structure that is to be obtained.

With reference to Figures 10 and 11, each side of the modular element 300 includes a pair of square frames 300F, each including four metal profiles 308A, 310A, 312A, 314A, joined together, for example by welding.

Each metal profile 308A, 310A, 312A, 314A has a hollow rectangular cross section and is traversed by rectilinear arrays of through holes H. The through holes H traverse each profile entirely; i.e., they are present on two opposite walls thereof.

The holes H provided on opposite sides of each frame 300F are moreover in corresponding and aligned positions so as to define a rectilinear passage, passed through which is a plurality of metal cables 304A, which are pre-tensioned and blocked in the condition that corresponds to pre-tensioning by means, for example, of conical elements.

In particular, fixing by means of conical elements is obtained as follows: the blocking device includes a first conical element and a second conical element, designed to penetrate into one another. A first of the two conical elements is housed directly in the perimeter frame of the modular element (both on the outer wall of the rectangular profile of the frame and on the inner wall), being jammed therein. It will preferentially be necessary to provide holes of slightly different size to take into account the different abutment diameter of the conical element on the inner and outer walls.

A second conical element, which is configured for being fitted into the first conical element, is in turn divided into two parts along the axis, and has a slightly larger aperture than the first conical element .

The two parts are then arranged around the cable

304A to be tensioned, which, for assembly, is chosen slightly longer in such a way that it sticks out of the frame so that it can be engaged by a jack that pre ^¬ tensions it.

When the jack is released, the cable will exert an action in the sense of co-penetration of the second conical element into the first, thus blocking the two parts of the second element in position on the cable 304A, which is consequently forced and blocked in the tensioning position.

Alternatively, it is possible to wind the cable 304A at each end round an eyelet element (which may possibly be embedded in the cable itself) , the diameter of which, which is much greater than that of the holes through which the cable 304A is passed, blocks the (pre-tensioned) position thereof with respect to the frame 302.

In greater detail, a first plurality of metal cables 304A is passed through the arrays of through holes H located on the opposite sides 308 and 312, meaning by this that on each frame 300F the cables 304A are tensioned between the profiles 308A and 312A. A second plurality of metal cables 304A is passed through the arrays of through holes H located on the opposite sides 308 and 312, meaning by this that on each frame 300F the cables 304A are tensioned between the profiles 310A and 314A.

The person skilled in the branch will appreciate that, on account of the geometry of the frames 300F and of the arrangement of the holes H, passage of the cables 304A within the arrays of holes H defines a mesh structure 304 consisting of a pair of tensile- structural nets 304' with quadrangular mesh (each tensioned on a corresponding frame) Preferentially, each cable is positioned and tensioned individually, without interweaving with other orthogonal (or in general non-parallel) cables. Alternatively, to simplify the modular element 300 and reduce the number of blocking elements necessary for tensioning the mesh structure 304, it is possible to pass one or more cables (in a number lower than the number of individual cables necessary) following one or more fret-like paths .

Preferentially, the centre-to-centre distance between holes H on opposite sides - designated by the letters A and B in Figure 12 - are chosen identical so that the mesh of the tenso-structural net has a square geometry. Preferentially, the value chosen for the centre-to-centre distance A and the centre-to-centre distance B is 100 mm.

The two frames 300F with the corresponding tenso- structural nets 304' already tensioned are coupled to one another by being set on top of one another with interposition of four angular inserts 315 of insulating material (which are substantially L-shaped) . In a preferred embodiment, the insulating material is cellular glass. The shape and arrangement of the angular inserts 315 (at the corners of the perimeter frame 302) are more clearly visible in Figure 12, where they are represented with dashed line. The ensemble of the frames 300F set on top of one another and of the angular inserts 315 set in between defines the perimeter frame 302, which has been mentioned at the outset of the description of the modular element 300.

Moreover arranged at each corner of the perimeter frame 302 are an inner corner plate 316 and an outer corner plate 317, which in this embodiment are L-shaped on account of the square shape of the frame 302. The corner plates 316 and 317 provide greater local strength to the frame 302 and stiffen the joint between the profiles of the frame that converge thereon (with gain/benefit in terms of span) , and moreover function as edge protection for subsequent application of the sheath 306, which, as in the case of the other embodiments described herein, is preferentially obtained as an envelope made of strong polymeric material, for example ETFE (ethylene tetrafluoro ethylene), and transparent.

The sheath 306 may be obtained, alternatively, from a single layer of plastic film of the necessary thickness, or else by superimposing a number of plastic films of a commercially available thickness until the total thickness is reached necessary for the multilayer sheath to limit deformation thereof under stress.

Vacuum is applied within the sheath 306 in such a way that the latter adheres tigthly to the frame 302 and to the tensile-structural nets defining the mesh structure 304.

For this purpose, the sheath 6 may be provided with a valve 318 (represented schematically in Figure 11) that can be connected to a vacuum pump for creating vacuum therein. For this purpose, it is clearly necessary for the sheath 306 to be impermeable to air or, in the case where the material of which it is made is not impermeable, it is necessary for the aforesaid material to be rendered such.

The valve 318, of the commercially available type for vacuum circuits, such as those used in refrigerating systems, must be connected to the sheath using a method that will preserve hermetic sealing of the sheath/valve ensemble, which acts as an envelope provided for the ensemble constituted by the frame 302, the mesh structure 304, and the cellular glass. An example consists in carrying out heat sealing or applying a flange with gaskets.

The valve 318 may be positioned, for example, as illustrated in Figures 13 and 14, i.e., in the top side of the rectangular profile of the frame, after having made a hole therein in which to insert the tube of the valve. By creating vacuum in the panel, the compressive force of the sheath 306 stabilises also the valve 318 by compressing the latter against the frame 302.

The tensile-structural nets 304' and the frames 300F are sized so as to counter the action of vacuum within the element 300, an action that would otherwise lead to structural collapse of the element itself. The inventor has noted how, as a possible example of optimal sizing of the element 300, namely, a sizing that represents an excellent compromise between constructional simplicity, structural strength, mass per unit area of the structure resulting from assembly of a number of elements 300, available refractive surface, and production costs, consists in a perimeter frame 302 having a square shape with a side of 1 m.

The wall thickness of each profile 308A, 310A, 312A, 314A, in the case where the material selected is steel (for example, S355 steel), is chosen of 5 mm for a preferential geometry of the (rectangular) cross section of dimensions 150 mm x 50 mm (base x height) . This results in a total weight of the two frames of approximately 100 kg. Alternatively, it is possible to resort to aluminium alloys (for example, Al 7075-T651, the so-called "Ergal") in order to reduce the total weight of the frame 302.

The material preferentially chosen for the cables 304A is spring steel for geotechnical purposes or prestressing techniques, characterized by a tensile strength of approximately 1.9 GPa (in this case, once again preferentially, seven (7) wires are used for an overall diameter of 9.6 mm) . Alternatively, it is possible to make the cables 304A using Spectra® fibres manufactured by Honeywell International Inc. This is, in particular, a polymer characterized by extremely high tensile strength (approximately 2 GPa) and high elastic modulus (approximately 171 GPa) . In the case of use of Spectra® fibres the individual wires are aligned parallel in the necessary number, typically ten (10) or twelve (12) to form the cable. In the case of use of twelve (12) cables, the diameter of each cable is chosen with a value of 1.295 mm.

On top of the sheath 306 there may moreover be applied a perimeter sheath of rigid material SHL - a so-called "shell" - (for example, an elastomer or a rigid polymer with good mechanical properties and low coefficient of thermal transmissivity) similar to the sheath 20 so as to protect the sheath 306 from any possible tears that might jeopardize the vacuum- tightness capacity thereof.

In various embodiments illustrated in Figures 13 and 14, the rigid shell SHL has a shape that performs also the function of anchorage to a rail RL1 installed on an existing load-bearing structure STR or on a structure that is under design, for example like the one illustrated in Figures 15 and 16 (the latter representing a slope A where there are provided a plurality of rails RL1 constituted by the stringers, and a vertical facade where the load-bearing rails RL1 are constituted by just the circular vertical pillars PL) .

In another example of installation, illustrated in Figure 15, the modules 300 have an elongated rectangular shape and cover the top part of the structure STR.

It is sufficient to have available load-bearing structures (the rails RL1) oriented parallel to just one of the sides of the modular element. In ordinary cases, the sole constraint is represented by the pitch of the main structures, which must be compatible with the geometry of the modular element 300.

It is to be noted, moreover, how the shell SHL also provides a hermetic connection between the various modular elements set side by side, accommodating the deformations of the perimeter frame contained therein.

In another example of assembly, illustrated in

Figure 15, the modular elements are anchored to the load-bearing structure via "Y"-shaped fixing elements (similar to those widely used for providing glazed facades) designated by the reference RL2, each having a first shape-fit element and a second shape-fit element RB at the free ends of the bifurcation that defines the Y geometry, which fit into compartments G2 of a complementary geometry obtained in the shell SHL.

It is to be noted that both of the connection elements RL1 and RL2 can be used indifferently for covering one or more facades of the structure STR as illustrated in Figures 15 and 16.

In this connection, the modular element 300 is preferentially conceived for construction of refractive coverings with high thermal insulation (in the case of Figure 16 the covering involves also one of the facades), and is suited for installation on a load- bearing structure such as, for example, the framework of a sloped roof (see again Figure 16) .

In this situation, provision of a network of headers and/or pneumatic connectors is envisaged, which connect the various valves 318 for application of vacuum according to a predetermined distribution pattern .