The present invention relates to the sector of aeration and air-conditioning systems.

As is known, said systems comprise ducts for conveying air that start or terminate in normally parallelepipedal containers called "plenum boxes".

There are intermediate distribution boxes or plenum boxes and terminal plenum boxes (for delivery) , to which mouths or grills for outlet- of air are usually applied. The ducts are the channels that connect the apparatuses for treatment of the air to the intermediate plenum boxes and/or to the terminal plenum boxes.

Currently, traditional intermediate plenum boxes and terminal plenum boxes are made of galvanized sheet ^l steel or panels made of foamed polyurethane .

In either cases, machining of the plenum boxes and their assembly is carried out in purposely equipped workshops, and the finished product is delivered to the distributor or to the installer complete with all of its parts.

A problem of the currently known plenum boxes, is represented by the fact that they present considerable costs both for their transport and for their subsequent warehousing. This is due to the fact that, even though they have a low weight, thanks to the fact that they are evidently empty, they occupy a large space both during transport and in the warehouse.

Their dimensions range from several centimetres per side (e.g., 25x23x17 cm) for the smallest up to the order of metres (e.g., 200x200x100 cm) for the largest. Normally, they vary according to the size of the diffusor or of the mouth and to the size of the ductwork associated thereto.

From what has been said so far, it emerges clearly that a product of the sort can have very different dimensions irrespective of the manufacturer and is difficult to store precisely on account of its volume: it will suffice to consider that a small commercial plenum box of dimensions 25x23x17 cm occupies a space with a volume of 9.775 cm ³ (equal to 0.009775 m ³ ) whilst a medium-to-large one can even reach

200x200x100 cm occupying 4.0 m ³ (equal to

4 000 000 cm ³ !) of warehouse.

The above considerations should be made taking into account that the manufacturers of aeraulic systems store on average approximately 20 000 plenum boxes of various size per year. Consequently, the encumbrance involved in their storage can be readily understood.

Some manufacturers of air-delivery mouths produce them by replacing the traditional galvanized steel or aluminium with plastic materials, enhancing what are the technical characteristics of plastic products, but then propose plenum boxes made of metal material.

The purpose of the present invention is to overcome the problems described so far by providing plenum boxes that can be warehoused with an extremely low encumbrance, as well as a process for their production.

This has been obtained, according to the invention, by envisaging production of terminal plenum boxes or intermediate plenum boxes or ductwork that can be assembled at the moment of their installation, which are designed to be stored in a plane configuration in a single non-assembled piece, occupying a thickness equal to that of the material of which they are made and a surface equal to the plane development of the total surface of the product to be assembled.

A better understanding of the invention will emerge from the ensuing description and with reference to the annexed figures, which illustrate, purely by way of non-limiting example, some preferred embodiments of the invention.

In the drawings :

Figures IA and IB show an intermediate plenum box and a terminal plenum box according to the known art;

Figure 2 is a 3D view of a first embodiment of the invention, for a terminal plenum box in a plane configuration;

Figure 3 is a 3D view corresponding to the embodiment illustrated in Figure 2, which shows an intermediate step of bending for assembly; Figure 4 is a 3D view showing a step of bending for assembly following that of Figure 3;

Figure 5 shows the terminal plenum box of Figure 2 fully assembled;

Figures 6 and 7, which correspond to Figure 2, are, respectively, a top plan view and a cross- sectional view according to the plane of trace A-A' of Figure 6;

Figures 8A and 8B, which are similar to Figure 6 and 7, regard a variant of Figure 2 in which the perimetral slotting means are constituted by just one male/female slotting element for each side;

Figures 9 to 12, which are similar to Figures 2 to 5, regard a duct with rectangular cross section;

Figures 13 to 16, which are similar to Figures 2 to 5, regard a second embodiment of a terminal plenum box, in which the hole for the air is on the bottom instead of on the side;

Figures 17 and 18 are 3D views of a collar for fixing the ductwork to the terminal plenum boxes or intermediate plenum boxes; and Figures 20 and 21 are, respectively, a top plan view and a cross-sectional view according to a diametral plane of the collar of Figures 17 and 18.

In what follows, reference will be made, for simplicity of exposition, to the production of terminal plenum boxes (Figure 2-5, 6-7, 8A-8B and 13-16), but what will be described can be applied directly and without modifications also to the production of intermediate plenum boxes and/or ductwork (Figures 9- 12). The terminal plenum boxes according to the invention can be made of any material of appropriate thickness, such as for example PVC, polycarbonate, sandwich material comprising at least one inner layer of plastic material and at least one outer layer of preferably metal coating, such as for example copper, stainless steel, painted or anodized aluminium. According to a peculiar characteristic of the invention, each terminal plenum box is made of a single sheet which can be assembled in five moves on site without the use of tools. Advantageously, since it is made of plastic material or multilayer material comprising at least one layer of plastic material, the terminal plenum box does not need to be thermally insulated in so far as the material of which it is made possesses insulating characteristics.

According to the invention, said single sheet has purposely provided predefined bending lines S, and the edges of the parts to be joined are provided with slotting engagement means A similar to those of the pieces of a jigsaw puzzle.

Said slotting engagement means comprise at least one male/female element A on the edge of each side to be joined, to which there corresponds a female/male element A having a shape that mates with the previous one, which is appropriately provided on the edge of the side to be joined to obtain assembly.

As illustrated clearly in Figures 2 to 5, which regard an example of embodiment of a terminal plenum box suitable for air-delivery diffusors provided with a side hole F for the air, according to the present invention it is assembled in a very simple and immediate way by bending the plane sheet back on itself along the bending lines S, just using one's hands and without the aid of particular implements. In particular, the bending lines are constituted by purposely prearranged grooves S that involve approximately one half of the thickness of the material of which the starting plane sheet is made.

In the example illustrated, all the bends are at right angles and consequently, the cross section of said grooves is substantially V-shaped with an angle at the vertex of 90° .

It should be noted that if the bends need to have an angle greater than 90° (i.e., an obtuse angle), the shape of the grooves S will be appropriately modified: if, for example, it is necessary to produce a terminal plenum box with a hexagonal cross section, the corresponding grooves will have an angle at the vertex substantially equal to 60°.

A second peculiar characteristic of the invention, regards the particular shape of the perimetral slotting means A that are provided along the edges of the parts that are to be fixed together to for the body of the terminal plenum box.

The process according to the invention substantially comprises the following steps:

• Study and definition of the plane development of the terminal plenum box to be made;

• Study of the trace of the bending lines S necessary for its assembly; • Study and choice of the shape for the perimetral slotting means A arranged along the edges of the plane development of the terminal plenum box;

• Formation of the grooves S along the trace of the bending lines; • Cutting of the sheet of starting material according to the perimeter defined by the plane development and by the shape of the perimetral slotting means .

From what has been said so far it emerges clearly that, by stacking the plenum boxes in a plane configuration instead of assembled in a three- dimensional configuration, the space occupied is represented by the volume defined by the total height of the pile of plenum boxes multiplied by the area of the polygon circumscribed to the plane development of the plenum box itself.

Consequently, the space occupied by a given number of plenum boxes stored in a plane configuration according to the present invention is drastically reduced with respect to the space that would be occupied by the same number of plenum boxes if they were stored in an assembled three-dimensional configuration .

The thickness of the plastic or sandwich material that can be used for the production of the terminal plenum boxes described so far is preferably equal to or greater than approximately 3 mm.

In the preferred embodiment that is described, said thickness is equal to 4 mm.

It should be noted that the higher the precision with which the edges of the shape of the plane development of the plenum boxes and of the perimetral slotting means A are cut, the greater the tightness of the products that are assembled.

In any case, it is expedient that, during assembly, along the bending lines S and along the edges of the slotting means A there should be distributed an appropriate sealant and/or adhesive of a known type.

From what has been said, it is evident that in addition to having a product of extremely high quality and tightness, the present invention advantageously enables an enormous saving thanks to the extremely high optimization of the spaces for transport and warehousing of the plenum boxes prior to their effective installation.

It is to be recalled that what has been said so far for the terminal plenum boxes is applicable, without modifications and with the same advantages, also to the production of intermediate plenum boxes and/or of ductwork for the air.

Figures 8A and 8B show a variant of the first embodiment in which just one male/female or female/male slotting element A is provided on each side to be joined.

Figures 9 to 12 show a second embodiment of the invention, regarding a ductwork with quadrangular cross section. In this case, the bending lines S are only longitudinal, but by increasing their number it is advantageously possible to produce ducts with polygonal cross section, with any number of sides up to ducts with substantially circular cross section. Figures 13 to 1'6 show a third embodiment of the invention, regarding a terminal plenum box in which the hole F for the ductwork is on the bottom.

Purely by way of example, it will suffice to consider that 10.000 standard steel plenum boxes of dimensions 25x23x17 cm occupy ^' approximately 120 m ³ of warehouse space, whilst 10.000 plenum boxes made of any material produced according to the present invention occupy approximately 2 m ³ of warehouse space.

In this connection, it should be noted that the comparison set forth above regards to the worst of cases: in fact, the larger the terminal plenum box or intermediate plenum box or ductwork, the greater the saving of space in the warehouse as compared to current solutions .

Evidently, given the minimum occupation of space, the plenum boxes according to the invention can be transported with fairly small-sized means, thus optimizing the transport costs.

Advantageously, the present invention provides an operative technical solution capable of satisfying the needs of:

• MANUFACTURERS;

• DISTRIBUTORS;

• INSTALLERS .

According to the present invention, it is expedient to use a purposely provided collar for connection of flexible tubes to the intermediate plenum boxes or terminal plenum boxes, which has outer circumferential grooves designed to define a seat for the edge of the hole provided in the plenum box and for fixing the flexible tube on the collar itself, thus facilitating assembly of the parts.