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Title:
APPARATUS FOR MAKING BENTONITIC NEEDLED GEOCOMPOSITE PRODUCTS
Document Type and Number:
WIPO Patent Application WO/2008/146074
Kind Code:
A1
Abstract:
Apparatus (1) for making needled geocomposite products comprising a plurality of rollers (21a-21f) that convey a geotextile support layer (11), for example unwound from a coil (10), in a first feeding direction (101). The geotextile support layer (11) arrives thus at a distributor (30) that spreads a swellable clay (31), for example bentonite on it. The apparatus comprises, furthermore, rollers (22a-22d) that convey a geotextile cover layer (13), unwound frora a coil (12), in a second feeding direction (102), of opposite direction, or coincident, with that (101) of the geotextile support layer (11). In particular, the geotextile cover layer (13) is conveyed by the rollers (22a-22d) in a laying area at which are provided three rollers (24, 25 and 26) adapted on one hand to keep stretched the geotextile layers (12, 13) and on the other hand to provide level the layer of bentonite 31 between them arranged. The three rollers (24- 26) supply the geotextile layers (11, 13) with the layer of bentonite sandwiched between them at a needling machine (50) that ne achieves the mutual connection by means of needling. More in detail, the needling machine (50) has a plate (51) , equipped with a plurality of needles (52), which is moved by actuating means in a reciprocation along a needling direction substantially orthogonal to the feeding direction (103) of the geotextile layers (11, 13).

Inventors:
DELLA PORTA CINZIA (IT)
STARITA PIETRO (IT)
Application Number:
PCT/IB2007/001445
Publication Date:
December 04, 2008
Filing Date:
June 01, 2007
Export Citation:
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Assignee:
LAVIOSA CHIMICA MINERARIA S P (IT)
DELLA PORTA CINZIA (IT)
STARITA PIETRO (IT)
International Classes:
B32B19/04; E02D31/00
Domestic Patent References:
WO2007030671A22007-03-15
WO2005056286A12005-06-23
Foreign References:
US5970893A1999-10-26
EP0278419A21988-08-17
EP0491453A11992-06-24
EP0491454A11992-06-24
Attorney, Agent or Firm:
CELESTINO, Marco (Viale Giovanni Pisano 31, Pisa, IT)
Download PDF:
Claims:
CLAIMS

1. Process for making needled geocomposite products, comprising the steps of:

— moving a geotextile support layer in a first feeding direction/

— spreading a swellable clay having measured granulometry on said geotextile support layer,,

— moving a geotextile cover layer in a second feeding direction, — laying the geotextile cover layer on said swellable clay,

— feeding an assembly consisting of said geotextile support layer, of said geotextile cover layer and of said swellable clay sandwiched between the two layers in a needling area,

— connecting said geotextile support layer, of said geotextile cover layer and of said swellable clay sandwiched between the two layers by means of a needling step obtaining a semifinished product, — dividing the semifinished product into a plurality of mat pieces obtaining a final product, characterised in that said needling step is effected by a plate equipped with a plurality of needles, said plate being reciprocated along a needling direction substantially orthogonal to the feeding direction of the geotextile layers.

2. Process for making needled geocomposite products, according to claim 1, wherein said reciprocation of the needling plate is assisted by lateral guiding means adapted to avoid a lateral shifting movement

during the needling step of the geotextile layers with the sandwiched swellable clay.

3. Process for making needled geocomposite products, according to claim 1, wherein said division of said semifinished product in said plurality of mat pieces is made through cutting means adapted to carry out a transversal cut on said semifinished product .

4. Process for making needled geocomposite products, according to claim 2, wherein during said transversal cut, said cutting means translate with said semifinished product performing therefore a cut during movement, said transversal cutting means running from a starting cutting configuration at which it cuts said semifinished product and translates in the same direction of said semifinished product, to a final cutting configuration at which it is external to said semifinished product and slide in an opposite direction returning to said starting cutting configuration. 5. Process for making needled geocomposite products, according to claim 2, wherein after said transversal cut, said semifinished product is subject to a longitudinal cut by a second cutting means.

6. Process for making needled geocomposite products, according to claim 1, wherein after said cut of said semifinished product into a plurality of mat pieces a winding step is provided of each of said parts about a core, obtaining corresponding coils of final product.

7. Process for making needled geocomposite products, according to claim 1, wherein after said winding step

a step of packaging said coils is provided coating it with a film of plastic material.

8. Process for making needled geocomposite products, according to claim 1, wherein said first feeding direction and said second feeding direction are substantially parallel.

9. Process for making needled geocomposite products, according to claim 1, wherein said swellable clay used is bentonite. 10. Process for making needled geocomposite products, according to claim 2, wherein a step is provided of changing the inclination of said lateral guiding means during said reciprocation of said plate.

11. Production process for making needled geocomposite products, according to claim 10, wherein said step of changing said inclination is lubricated by grease.

12. Apparatus for making needled geocomposite products comprising: — means for moving a geotextile support layer in a first feeding direction,

— means for spreading a swellable clay having measured granulometry on said geotextile support layer, said means for spreading being arranged at a loading station,

— means for moving a geotextile cover layer in a second feeding direction,

— means for laying the assembly consisting of said geotextile cover layer on said swellable clay, said means for laying being provided at a laying station,

— means for feeding the assembly consisting of said geotextile support layer, of said geotextile cover layer and of said swellable clay sandwiched between the two layers in a needling area, — means for binding said geotextile support layer, said geotextile cover layer and said swellable clay sandwiched between them, said means for binding needling said geotextile and said clay arranged among them obtaining a semifinished product, — cutting means adapted to carry out a division of said semifinished product into a plurality of parts, characterised, in that said means for binding comprise a plate equipped with a plurality of needles and moved by actuating means in a reciprocating motion along a needling direction that remains substantially orthogonal to the conveying direction said geotextile layers.

13. Apparatus for making geocomposite products, according to claim 12, wherein said actuating means are associated with suction means from the needling area of said clay.

14. Apparatus for making geocomposite products, according to claim 12, wherein lateral guiding means are provided for said plate adapted to avoid a lateral shifting movement during the needling step of said geotextile with said sandwiched swellable clay.

15. Apparatus for making geocomposite products, according to claim 12, wherein feeding comprise:

— a first roller adapted to rotate in a first direction for causing the movement of said geotextile support layer towards a clay spreading zone;

— a " second roller counter rotating with respect to said first roller adapted to cause the arrangement the assembly consisting of said geotextile cover layer on said powder; — a third roller counter rotating with respect to said second roller and adapted to bring said geotextile support layer, said powder and said geotextile cover layer at said plate.

16. Apparatus for making geocomposite products, according to claim 12, wherein, furthermore, means are provided for removing said powder.

17. Apparatus for making geocomposite products, according to claim 12, wherein said cutting means comprises: — longitudinal cutting means,

— transversal cutting means,

— a combination thereof.

18. Apparatus for making geocomposite products, according to claim 12, wherein said transversal cutting means are mounted on a carriage sliding along a direction substantially parallel to the conveying direction of said semifinished product, said carriage being moved along said conveying direction at the same speed of said semifinished product. 19. Apparatus for making geocomposite products, according to claim 12, wherein said means for removing the powder comprise at least one nozzle connected to a slightly pressurized air system, or alternatively a vacuum system, in order to remove the powder of swellable clay from the working area by means of an air blow, or by suction.

20. Apparatus for ' making geocomposite products, according to claim 12, wherein said means for moving said geotextile support layer and said means for moving said geotextile cover layer comprise a plurality of rollers associated with means for controlling the tension of said geotextile layer, suitable to ensure a fixed and controlled tension during the work.

21. Apparatus for making geocomposite products, according to claim 18, wherein said means for controlling the tension comprise a plurality of dancing rollers.

22. Apparatus for making geocomposite products, according to claim 12, wherein said means for actuating said plate into said reciprocating motion provide a connecting rod/crank system comprising a first and a second connecting rod having an end pivotally connected to the needling plate and to a lateral guiding bar, said lateral guiding bar having, moreover, the other end hinged to a fixed frame in order to form with it an angle of variable amplitude during the reciprocation.

23. Apparatus for making geocomposite products, according to claim 12, wherein said plate has a plurality of needles corresponding to a concentration set between 1000 needles/m 2 and 10.000 needles/m 2 .

24. Apparatus for making geocomposite products, according to claim 14, wherein transmission means are provided that allow to adjust the inclination of said lateral guiding means during the reciprocation of said plate.

25. Apparatus for making geocomposite products, according to claim 24, wherein means are provided for a grease lubrication of said transmission means.

26. Bentonitic needled product comprising a support layer of a geotextile material, a cover layer, which are also of geotextile material and a measured amount of a swellable clay in powder sandwiched between them, said support layer, said cover layer and said powder being connected through a plurality of points characterised in that they are made according to the process described in claims from 1 to 8.

27. Bentonitic needled product according to claim 26, wherin bentonite used is in the form of a powder having the following granulometry: - 90% by weight smaller than 70 μm, 50% by weight smaller than 30 μm,

10% by weight smaller than 9 μm.

28. Bentonitic needled product according to claim 26, where bentonite used is in the form of granules having the following granulometry:

- 90% by weight larger than 70 um,

- 50% by weight larger than 0.6 mm,

- 10% by weight larger than 1.5 mm.

Description:

TITLE APPARATUS FOR MAKING BENTONITIC NEEDLED GEOCOMPOSITE PRODUCTS

DESCRIPTION Field of the invention The present invention relates to an apparatus for making bentonitic needled geocomposite products used for waterproofing applications in geotechnical engineering, for example as coating barrier for retaining structures, reservoirs, bank protection, etc. The invention relates also to a method for making bentonitic needled geocomposite products .

Background of the invention

Normally bentonitic geocomposites are made sandwiching layer of bentonite between two geotextile layers, and precisely a support layer and a cover layer.

In particular, bentonite is a waterproofing matrix whereas the geotextile layers act as a protecting wrapper that gives the system manoeuvrability and mechanical resistance. During hydration water molecules are blocked both in the bentonite clay particles, and in interspaces between the particles, so that bentonite swells preventing water from draining. Owing to the remarkable waterproofing features, the bentonitic geocomposites can be used for geotechnical application, like environment protection, to coat the bottom of dumps, for waterproofing sites, for example before casting concrete foundations, to assist the construction of water reservoirs and channels, to protect the groundwater tables, etc.

Geocomposites can be classified according to the type of connection used for fastening the layer of bentonite to the geotextiles. A first type of connection provides special bonding materials that ensure the connection between the geotextile layers and bentonite, without affecting its functionality. Another type of connection provides thermo-gluing, made for thermal coupling of the geotextile layers, owing to free fibres present in one of the two geotextile layers. A further process provides the connection of the three layers by means of mechanical systems such as by needling, seaming, or quilting. This bonding system increases resistance against inner friction.

The needling process provides, in particular, the use of plates having special hooked needles that quickly reciprocate causing part of the fibres of the upper geotextile cover layer to pass through the central bentonite layer and fix them to the lower geotextile support layer. In particular, this type of fastening gives to a bentonitiσ geocomposite material a high steadiness.

However, the machines presently used in the production of needled geocomposite products have many drawbacks.

Firstly, such machines provide a lubrication of the mechanical parts normally made through oil dipping. Therefore, the risk is high of polluting the final product with lubrication oil owing to losses or leakings.

In particular, the lubrication oil besides polluting the final product can mix with the clay powder forming a mixture that penetrates in the mechanical parts and can cause jammings, causing the machines to stop for cleaning.

In addition to the above, the known processes for making needled geocomposite products provide a succession of operations alternated to waiting times to allow the different machines of the production line to synchronize. In other words, the automatic production lines of needled geocomposite products have dancing times that slow down the overall process.

Summary of the invention

It is a feature of the present invention to provide an apparatus for making bentonitic needled geocomposite products capable of providing needled geocomposite products in a completely automatic way.

It is another feature of the present invention to provide an apparatus for making bentonitic needled geocomposite products capable of making easier the maintenance steps with respect to the machines of the prior art.

It is a particular feature of the invention to provide an apparatus for making bentonitic needled geocomposite products with improved features, in particular, concenring waterproofing capacity, with respect to the products of the prior art.

It is also a feature of the present invention to provide an apparatus for making bentonitic needled geocomposite products that avoids a possible contamination of the final product, in particular, by lubrication oil by means of losses, or leaks.

These and other features are accomplished with one exemplary production process for making needled geocomposite products, comprising the steps of:

— moving a geotextile support layer in a first feeding direction;

— spreading a swellable clay having measured granulometry on said geotextile support layer, — moving a geotextile cover layer in a second feeding direction,

— laying the geotextile cover layer on said swellable clay,

— feeding the assembly consisting of said geotextile support layer, of said geotextile cover layer and of said swellable clay sandwiched between the two layers in a needling area,

— connecting said geotextile support layer, said geotextile cover layer and said swellable clay sandwiched between the two layers by means of a needling step obtaining a semifinished product,

— dividing the semifinished product into a plurality of mat pieces obtaining a final product, whose main feature is that said needling step is effected by a plate equipped with a plurality of needles, said plate being reciprocated along a needling direction substantially orthogonal to the feeding direction of the geotextile layers.

Advantageously, the reciprocation of the needling plate is assisted by lateral guiding means adapted to avoid a lateral shifting movement during the needling step of the geotextile layers with the sandwiched swellable clay.

In particular, the division of the semifinished product into a plurality of mat pieces is made through

cutting means adapted to carry out a transversal cut of the semifinished product.

Preferably, during the transversal cut, the cutting means translate with the semifinished product obtaining therefore a cut during movement. More in detail, the transversal cutting means moves from a starting cutting configuration at which they begin the cutting stroke of the semifinished product and translate in its same direction, to an ended cutting configuration at which it is external to the semifinished product and slide in an opposite direction returning to the starting cutting configuration.

Advantageously, after the transversal cut the final product can be subject to a longitudinal cut by a second cutting means, said longitudinal cut being made at the sole side portions of the semifinished product, or alternatively, also at a central portion.

After cutting the semifinished product into a plurality of mat pieces a winding step is provided of each mat piece about a. core, for example of cardboard, obtaining corresponding coils of needled geocomposite product.

At the end of the winding step, a following packaging step can be furthermore provided of the coils that are coated with a film of plastic material.

Advantageously, the first feeding direction and the second feeding direction are substantially parallel.

Preferably, the swellable clay used is bentonite.

Advantageously a step of changing the inclination of said lateral guiding means is provided during the reciprocation of said plate. In particular, said step of

changing the inclination is lubricated by grease. This way, besides having a higher seal from powder a contamination is also avoided of the final product by oil drops generated by possible and frequent leakings, which are a problem in the prior art.

According to another aspect of the invention, an apparatus for making needled geocomposite products comprises:

— means for moving a geotextile support layer in a first feeding direction,

— means for spreading a swellable clay having measured granulometry on said geotextile support layer, said means for spreading being arranged at a loading station, — means for moving a geotextile cover layer in a second feeding direction,

— means for laying the geotextile cover layer on said swellable clay, said means for laying being provided at a laying station, — means for feeding the assembly consisting of said geotextile support layer, of said geotextile cover layer and of said swellable clay sandwiched between the two layers in a needling area,

— means for binding said geotextile support layer, said geotextile cover layer and said swellable clay sandwiched between them, said means for binding needling said geotextile layers and said swellable clay sandwiched between the two layers obtaining a semifinished product,

— cutting means adapted to carry out a division of the semifinished product into a plurality of mat pieces obtaining a final product, whose main feature is that said means for binding comprise a plate equipped with a plurality of needles moved by actuating means in a reciprocation along a needling direction that remains substantially orthogonal to the feeding direction of the geotextile layers.

In particular, the reciprocation of the needling plate is assisted by lateral guiding means that avoid a lateral shifting movement during the feeding movement.

Furthermore, means can also be provided for removing from the needling area, and at other zones of the apparatus, the powder and/or the granules of swellable clay. This way, it is avoided that the powder and the granules of the swellable clay can penetrate in the mechanical parts of the apparatus jeopardizing the correct operation of the same.

Advantageously, the feeding means comprise: — a first roller adapted to rotate in a first direction of rotation for causing the motion of the first geotextile towards a spreading zone;

— a second roller counter rotating with respect to the first roller adapted to cause the second geotextile to move parallel over the first geotextile layer;

— a third roller counter rotating with respect to the second roller and adapted to convey the geotextile support layer, the swellable clay and the geotextile cover layer in a feeding direction towards the needling plate.

In particular, the above described three rollers stretch the geotextile layers and level the layer of swellable clay located between them in order to avoid the production of wrinkles. Advantageously the cutting means comprises:

— longitudinal cutting means,

— transversal cutting means,

— a combination thereof.

In particular, the longitudinal cutting means can be arranged exclusively at the side portions of the finished products, or alternatively, also at one or more central portions in order to increase the production flexibility of the apparatus.

Advantageously, the transversal cutting means are mounted on a carriage sliding along a direction substantially parallel to the conveying direction of the semifinished product. More in detail, the carriage is moved along the conveying direction at the same speed of the semifinished product. This way, the production is made continuously without the need of stopping the apparatus-

Advantageously, the means for removing the clay comprise at least one nozzle connected to a slightly pressurized air system, or alternatively a vacuum system, in order to remove the powder of swellable clay from the working area by means of an air blow, or by suction.

Advantageously, the means for moving the geotextile support layer and the means for moving the geotextile cover layer are associated with means for controlling the tension of the geotextile layers suitable to ensure a fixed and controlled tension during the production

process. Preferably, the means for controlling the tension comprise a plurality of dancing rollers.

In particular, the means for actuating the needling plate reciprocation provide a connecting rod/crank system comprising a first and a second connecting rod having an end pivotally connected to the needling plate and to a lateral guiding bar, said lateral guiding bar having, moreover, the other end hinged to a fixed frame in order to form with it an angle of variable amplitude during the reciprocation.

Advantageously, the concentration of needles on the surface of the needling plate is set between 1000 needles/m 2 and 10.000 needles/m 2 .

Advantageously transmission means are provided that allow to adjust the inclination of said lateral guiding means during the reciprocation of the needling plate. In particular, means are provided for grease lubrication of said transmission means. This way, besides having a higher seal from powder and contamination it is also avoided for the final product that oil drops fall generated by possible and frequent leaks.

According to a further aspect of the invention, a bentonitic needled product comprises:

— a support layer of a geotextile material, — a cover layer, which is also of a geotextile material,

— a measured amount of a. swellable clay in powder arranged between the geotextile support layer and the geotextile cover layer,

wherein the support layer, the cover layer and the powder are connected by means of a needling step using the apparatus above described.

Preferably, the used bentonite is in the form of a powder having the following granulometry:

- 90% by weight sized less than 70 um,

50% by weight sized less than 30 um,

- 10% by weight sized less than 9 um. Alternatively, the used bentonite is in the form of granules having the following granulometry:

90% by weight larger than 70 um,

- 50% by weight larger than 0.6 mm,

- 10% by weight larger than 1.5 mm.

In particular, the use of bentonite in granules allows reducing remarkably the environmental impact of the used materials both in the application both in the production, with respect to the use of the powder which is much easier to scatter. The use of bentonite in granules is possible owing to the improved intrinsic features of the bentonite used.

In particular, the geotextile support layer and the geotextile cover layer are fed at a speed set between 0.1 m/min and 15 m/min.

In particular, the support layer and the cover layer are made of a material selected from the group comprised of:

- fabric;

- non-woven fabric; knitted fabric;

- plastic sheets.

Brief description of the drawings

The invention will be now shown with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings wherein:

Figure 1 shows diagrammatically an apparatus for making needled geocomposite products, according to the invention,

- Figure 2 shows diagrammatically an exemplary embodiment of the apparatus of figure 1,

- Figure 3 shows in detail a perspective view of the laying station provided in the apparatus of figure 1,

- Figure 4 shows diagrammatically the main parts of the needling machine provided in the apparatus of figure 1, - Figures 5 and 6 show diagrammatically the transversal cutting means, provided in an exemplary embodiment of the apparatus of figure 1, in two different working configurations,

- Figure 7 shows diagrammatically the packaging station provided in an exemplary embodiment of the apparatus of figure 1.

Description of a preferred exemplary embodiment Figure 1 shows diagrammatically a possible apparatus 1 capable of carrying out the process for making needled geocomposite products, according to the invention. It provides a plurality of rollers 21a-21f that convey a geotextile support layer 11, for example unwound from a coil 10, in a first feeding direction 101.

Geotextile support layer 11 arrives thus at a distributor 30 that spreads a swellable clay 31, for example bentonite on it. The distributor 30 can provide, for example, a roller 35 with a resilient belt having

randomized pointed pins to ensure an homogeneous distribution of bentonite 31 on geotextile support layer 11.

The apparatus comprises, furthermore, rollers 22a- 22d that convey a geotextile cover layer 13, unwound from a coil 12, in a second feeding direction 102, in an opposite direction, or a coincident direction, with respect to direction 101 of geotextile support layer 11. Rollers 21a-21f and rollers 22a-22d can be dancing rollers in order to ensure unwinding geotextile layers 11 and 13 with a fixed and controlled tension.

In particular, geotextile cover layer 13 is conveyed by rollers 22a-22d in a laying area at which three rollers 24, 25 and 26 are provided adapted on one hand to keep the geotextile layers 12 and 13 stretched and on the other hand to level the layer of bentonite 31 between them arranged. This way, the production is avoided of wrinkles on geotextile layers 11 and 13 that would jeopardize a correct unwinding in the next steps. In particular,, geotextile layers 11 and 13 with the layer of bentonite sandwiched between them are fed by the system three rollers system 24-26 above described to a needling machine 50 that effects a mutual connection by means of needling. More in detail, needling machine 50 has a plate 51, equipped with a plurality of needles 52, which is moved by actuating means to reciprocate along a needling direction substantially orthogonal to the feeding direction 103 of geotextile layers 11 and 13.

In a possible exemplary embodiment of the invention, and shown in figure 4, the means for actuating the needling plate 51 in the reciprocating movement provide a

connecting rod/crank system 60 comprising a first connecting rod 61 and a second connecting rod 61' having respective end 62 pivotally connected to the needling plate 51 and to ends 71, or 71' , of respective lateral guiding bars 70 and 70' . More in detail, each lateral guiding bar 70, or 70', has another end 72, or 72', hinged to a fixed frame 75 in order to form with it an angle α having a variable amplitude during the reciprocation. In particular, the connecting rod/crank system 60 assisted by the lateral guiding bars 70 and 70' allows actuating the •needling plate 51 through a succession of positions in planes parallel to each other.

The lubrication of the mechanical parts contained in a carter of protection 76 that allow to adjust the inclination of the lateral guiding bars 70 and 70' is, in particular, made by grease, differently from the traditional systems that instead provide a lubrication by dipping it in oil. This way, besides having a higher seal from powder and contamination, it is also avoided that in the final product oil drops fall generated by possible and frequent leaks.

At the outlet of the needling machine 50, a semifinished product 15 thus obtained is subject to a transversal cutting step in order to obtain a plurality of mat pieces of desired length.

Ks diagrammaticalIy shown in figures 5 and β, the transversal cutting means, for example having a single blade 45, can be mounted on a support 44 integral to a carriage 17 sliding on a rail 18 arranged parallel to the conveying direction of the semifinished product 15. In particular, by operating the carriage 17 at the same speed

of semifinished product 15 it is possible to carry out the cut during movement of the semifinished product. More in detail, the transversal cutting means 45 moves from a starting cutting configuration (figure 5) at which they begin the cutting stroke of the semifinished product 15 and translate in its same direction, to a final cutting configuration (figure 6) at which they are external to the semifinished product 15 and slide in an opposite direction returning to the starting cutting configuration. The cut during movement above described avoids stopping the apparatus 1 to separate two following mat pieces to provide therefore a continuous process.

After the transversal cut above described of semifinished product 15 can be, furthermore, subject even at a longitudinal cut by a second cutting means, for example to cutter. More in detail, the longitudinal cutting means can be arranged only at the side borders, for trimπuαing laterally the semifinished product 150, or also at the central portion to obtain boards of desired size.

After the cutting operations, the final product 150 can be subject to an in line packaging step. For example, the packaging step can provide winding the product 150 about a stiff core 82 made by means of two counter rotating rollers 83 and 84. More in detail, each core 82 can be supplied by a lifting device 85 in a winding area 87 where the rollers 83 and 84 are arranged that carry out the growth of a coil 155 up to a desired diameter. Once achieved the desired diameter for coil 155, about it a film of plastic protection material is wound.

The production plant above described allows then to optimize the process for preparing products bentonitic needled causing it to be integrally automatic and speeding it up then remarkably with respect to apparatus of the prior art.

Furthermore, parameters important for evaluating the quality of the bentonitic needled geocomposite products, are shown by the mass ratio (g/m 2 ) and by the effective mesh spacing (mm) of the used materials for the geotextile cover layer and support layer. From such parameters, in fact, the efficiency depends of the cohesion of perforation of the needles and the containing capacity of the clay particles. The needled geocomposite product obtained with the process above described is in particular, improved with respect to the products of the prior art, since it has values of mass ratio set between 150 and 350 g/m 2 and mesh spacing set between 0.02 and 1.5 um.

The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.