WO2009130672A1

WO2009130672A1 - Multi - functional carpet for sport fields

Info

Publication number: WO2009130672A1
Application number: PCT/IB2009/051651
Authority: WO
Inventors: Renzo Poduti
Original assignee: Principi, Adalberto
Priority date: 2008-04-24
Filing date: 2009-04-22
Publication date: 2009-10-29
Also published as: ITRM20080223A1; EP2297403A1

Abstract

The present invention refers to an innovative carpet to be placed under a synthetic turf for sport fields or the like, in order to perform drainage functions, give elasticity to the playground and allow ventilation of the turf itself in order to be able to rapidly dry up following, e.g., any precipitation.

Description

MULTI-FUNCTIONAL CARPET FOR SPORT FIELDS DESCRIPTION

The present invention refers to an innovative carpet to be placed under a synthetic turf for sport fields or the like, in order to perform drainage functions, give elasticity to the playground and allow ventilation of the turf itself in order to be able to rapidly dry up following, e.g., any precipitation. History of the technology

Sport fields made with synthetic turf, in particular those made with synthetic turf of the so-called "last-generation" type, have attained enormous success and diffusion in the last years, thanks above all to the scarce maintenance they need, in comparison with sport fields made with natural turf.

In fact, as is known to those skilled in the art, natural turf sport fields suffer from the problem related to the need to make an effective water drainage system for waters which can incidentally accumulate thereon, e.g. due to precipitation. The first fields were made with a substantially leveled surface and, having therefore scarce draining properties, water tended to accumulate thereon. Sporting activity carried out under such conditions caused field deterioration, which made it difficult to carry out the activity itself. The ever more frequent implementation of synthetic turf for the making of sport fields contributed, at least partially, to solve the difficult problem of field drainage, needed in case the field itself is exposed, as mentioned, to precipitation. Description of the prior art

To date, for the making of synthetic turf sport fields first of all an excavation work has to be performed over all the surface of the field to be made, for a depth that usually is in the neighborhood of 30 cm. Subsequently, on the bottom surface rectilinear excavations are carried out, made transversally with respect to the sides of the field surface, which is usually rectangular. Draining pipes, known to those skilled in the art as "drain pipes" are positioned inside the rectilinear excavations, after having laid over the entire bottom surface, and therefore also inside said rectilinear excavations, a geotextile fabric in order to stabilize the field plane. Crushed aggregate is interposed between each draining pipe and the respective rectilinear excavation, in order to fix the draining pipe within the excavation. Then, the inside of the excavation is filled with inert material having a progressively decreasing grain size, from the excavation bottom to the playing surface. Therefore, the inert material has a first "ballast" bottom layer, then a layer of crushed aggregate, a next layer of grit until reaching the texture of sand, on which the artificial turf is positioned. The field surface is leveled so as to have four slopes and therefore have a respective inclination both toward each of its two long sides and each of its two short sides; for this reason, the field surface, along its entire peripheral development, water-collecting conduits. Water, collected by both the above-described drain pipes and the peripheral conduits, reaches sump pits, them also positioned peripherally to the field, and is subsequently disposed of.

As a person skilled in the art will surely appreciate, the described process entails remarkable drawbacks as it is particularly burdensome and complex. In the current state of the art, for the making of suchlike works other two methodologies have been introduced that, at least partly, simplify and improve playing field making, with specific reference to the water drainage system. A first methodology relates to the use of a geocomposite, called "geodrain", consisting of a geonet made of high density polyethylene (HDPE) having a structure of corrugated type, interposed in a sandwich-like fashion between two sheets of "nonwoven fabric".

"Nonwoven fabric" (also referred to as NWF) is a general term denoting an industrial product, similar to a fabric but obtained by processes other than weaving. In the applications described in the present patent application, such a nonwoven fabric is obtained by resins and nonwoven synthetic fibers, which undergo complex processes. When geodrain is used, the field is leveled with two slopes facing the two long sides,

^* according to^~a typically roof-like configuration. Therefore, the collecting conduits are positioned only along the two long sides of the field. On the ground thus leveled a polypropylene sheet is laid, thereon the geodrain is positioned and finally the artificial turf is placed. Rainwater pouring on the field and crossing the turf is conveyed to the collecting conduits by combined action of the geodrain and the polyethylene sheet lying therebelow.

A second methodology relates to the use of another system, with the difference that between the two sheets of nonwoven fabric it is interposed, instead of the corrugated geonet, a layer made of SBR (Styrene Butadiene Rubber)-type rubber granules mixed with polyurethane resins. Mixing takes place so as to manufacture a resilient and porous structure. The layer of rubber and mixed resins has a density such as to give draining properties to the layer itself. At the bottom of said system, as in the preceding one, an HPDE polyethylene sheet is arranged. In this case as well, water crossing the turf is conveyed to the collecting conduits by combined action of the layer of rubber and mixed resins and the polypropylene sheet.

With respect to the geodrain-using system, said second system carries out an anti- shock or dampening function, i.e., it gives to the field surface specific elastic properties that are needed to the ends of a correct playing and, at the same time, crucial in order to guarantee athlete safety. In fact, recent regulations set precisely what should be the impact strength the playing field has to offer, making reference to the energy portion absorbed by a deformation of the field during the bouncing of a ball on its surface. With the geodrain system such an impact strength feature is obtained by tamping a layer of elastomeric granules into the turf, or even by the aid of a porous rubber mat underlying the geodrain, which is to give impact strength properties to the field without having any function related to water drainage. The two systems described above entail advantages with respect to the process providing the use of aggregates of various grain sizes and drainage making by means of drain pipes. In fact, they allow to eliminate the ground-excavating, step, and therefore the transport of debris, with great benefits for the environment since otherwise debris are brought to a public dumping ground. Moreover, it is not necessary anymore to provide the works with remarkable amounts of inert materials, washed and having different grain sizes, for filling the excavation as described above, thereby obviating to the ever more difficult availability of the same nearby the worksite, and avoiding an extraction of such inert materials from the environment (generally from quarries). As is evident, by said systems there are avoided: the making of transversal and peripheral drainage by excavation; the laying of drain pipes; the use of geotextile ^~ Over the- entire surface of the laying plane of the foundation required-for ground" soil stabilization; the making of the four slopes, and therefore the laying of collecting conduits along the two short sides of the field. Drawbacks of the prior art Despite the fact that the two systems of the known art, based on the use of the geodrain and of the subcarpet made with rubber granules held together by two NFW sheets, provide remarkable advantages with respect to the classic process, they do not solve the problem once and for all. In fact, even the above-mentioned drainage systems entail evident drawbacks. Referring to the geodrain, the high-density corrugated geonet, besides from having no anti-shock effect, is characterized by having a certain deformability depending on the operating temperature, and a scarce suitability for vehicles. In particular, the material composing the geonet, as well as its corrugated structure, is scarcely suited to endure loads greater than those envisaged, which occur during standard sport activities. E.g., should it be necessary to transit on the playing field with a vehicle for carrying out maintenance activities, the underlying geodrain would surely be damaged by it, thereby undermining its planarity draining properties.

In addition, geodrain use dictates HDPE sheet laying for water canalization, thereby requiring further work and entailed higher costs. Finally, geodrain is produced in sheets that have to be laid on the ground and secured thereamong on-site, e.g. by gluing. 5 The system based on subcarpet use instead offers the anti-shock function, but requires it also the preventive laying of an HDPE sheet on the ground, with the entailed further work and greater making costs. In this case as well, the system is made of modules of reduced dimensions that have to be assembled on-site. Moreover, with this system a turf aeration - fundamental in order to allow turf drying - may occur only from

10 the outside of the field, therefore taking considerable time. Objects of the invention

Object of the present invention is to solve the above-mentioned drawbacks by providing a carpet as substantially described in claim 1 , a sport field as substantially described in claim 17 and a method for making a sport field as substantially described

15 in claim 21.

Further features of the process are defined in the corresponding dependent claims thereof.

Advantages of the invention

The present invention, by overcoming the mentioned problems of the known

20 art, entails several evident advantages.

— .- .-r ^"The-carpet sϋbj^"ect-matfer of the^'present

very high ability to drain field water, as will be described in detail hereinafter, with no need to add further supports, like e.g. the polypropylene sheet, to its bottom. Moreover, the carpet subject-matter of the present invention gives to the field surface

25 the required anti-shock properties, fundamental for athlete safety and the attainment of the various approvals by the controlling bodies in charge.

The carpet subject-matter of the present invention, thanks to its constructive features, undergoes no appreciable deformation both at high temperatures (about 100 °C) and at low temperatures (about -40 ⁰C) and is able to endure high loads without

30 undergoing deformations, allowing, if necessary, playing field suitability for vehicles, even vehicles weighing over 50 tons.

The field equipped with the carpet subject-matter of the present invention obviously does not need all the working related to the classic-type process (foundation with aggregates), and is positioned directly on the leveled ground, with two slopes facing

35 each a respective long side of the field ending on a respective collecting conduit.

The innovative carpet may be produced by a special continuous process, with a length depending on the specific dimensions of the field to be made.

Another important advantage of the carpet lies in its extreme longevity. As the old turf is removed and the new one is laid, for known draining systems it is necessary to carry out restoration and or replacement works, as over time their physical and performance 5 features fail. Thanks to its physical features, the carpet subject-matter of the present invention remains unaltered over time, allowing to remove the worn turf and re-lay the new one without further working and with remarkable economic and execution time savings. In addition, since carpet properties do not alter over time, in case the sport field is to be used no longer it could be removed and entirely recycled. 10 The carpet subject-matter of the present invention is manufactured in compliance with DIN 18035 Standard, used by European Federations to determine toxicity of anti-shock materials used in synthetic turf sport fields, which determines release limits of noxious substances, such as aromatic polycyclic materials, aromatic amines and heavy metals, from said materials.

15 The carpet, thanks to its innovative features that will be described in detail hereinafter, allows aeration below the synthetic turf, speeding up drying time following precipitations and thereby improving durability of the turf itself. Brief description of the drawings

Still further advantages, as well as the features and the operation modes of the 20 present invention will be made apparent in the following detailed description of a

^■-^{■ '}preferred ^"embodiment thereof, given by way of ^"example -^:and ^"not for limitative^' purposes. Reference will be made to the figures of the annexed drawings, wherein:

Figures 1 , 2A and 2B respectively show a playing field in perspective and two water drainage systems in a side view according to the known art;

25 Figure 3 shows in perspective a playing field according to the present invention;

Figure 3A shows in a side view a detail of Figure 3; Figure 4 shows in a perspective view the detail of Figure 3; Figure 5 shows in a perspective view a carpet according to the present invention;

30 Figures 6A, 6B, 6C show in a front view a section of the carpet of Figure 5 along line A-A;

Figures 8A and 8B depict a sectional view of two carpets according to the present invention connected therebetween;

Figures 7, 8, 9 and 10 illustrate the steps of a method for making a sport field 35 according to the present invention. Detailed description of the drawings

Referring to Figure 1 , a playing field 100 made according to the known art is shown, of which for simplicity's sake only one half is depicted. In particular, it can be seen how the playing field 100, of rectangular shape, has two slopes (whose inclination is obviously exaggerated in the figure in order to make it appreciable) symmetrical with respect to a center line 31 aligned with a long side thereof. Each slope converges on a respective water collecting conduit 300, 300'.

Referring to Figure 2A, it is illustrated in a sectional side view a detail indicated in Figure 1. In particular, there can be seen an artificial turf 2 and a bottom ground 400, between which a geodrain layer 201 is interposed; a polyethylene sheet 202 is positioned at the bottom of layer 201. As indicated by arrows in the Figure, water precipitating on the turf (e.g., due to precipitations) is drained via a combined action of the geodrain layer and the polyethylene sheet, thanks to the inclination (it also exaggerated in the figure) of the slope toward the collecting conduit 300. In a wholly analogous manner, Figure 2B depicts the detail of Figure 1 when a subcarpet (denoted by reference 210) is used, interposed between the artificial turf 2 and the polyethylene sheet 202.

Referring to next Figure 3, a sport field 3 according to the present invention is shown in a perspective view. By way of example and not for limitative purposes, the sport field 3 is a soccer field having a playing surface 6 and of which, for simplicity's sake, only one half is depicted. The sport field-3,-in the same manner of the field made according to the known art, has a rectangular shape having due long sides 18 and 18', two short sides (only one of which is visible in figure and denoted by reference 118), and two slopes, respectively denoted by number references 9 and 9'. The slopes 9 and 9' converge each on a respective collecting conduit 300, 300' and are symmetrical with respect to a center line 31 aligned with the long sides 18 and 18' of the field 3. It is understood that the choice of making a pair of slopes symmetrical with respect to the center line of the field is described herein merely by way of example and not for limitative purposes, it being understood that there could be adopted, in a wholly equivalent manner, other ways to make the slopes.

Referring now to Figure 3A, a side section of the field 3 is shown. In particular, there can be seen the artificial turf 2, in all similar to that used for known-art fields, this time overlapped to a carpet 1 according to the present invention. The carpet 1 has a laying bottom surface 14 for laying into contact with the bottom ground 400. The carpet 1 according to the present invention, by being placed on the bottom ground 400 at the slope 9, is such as to drain a fluid (denoted in Figure by arrows f) to the respective collecting conduit 300 by effect of gravity. In particular, the fluid to be drained usually is, as a non-limiting exemplary case, rainwater.

Referring to Figure 4, a carpet 1 according to the present invention is shown in perspective, positioned below the artificial turf 2. In figure, the turf 2 is only partially

5 depicted, merely to show the carpet 1 placed therebelow and illustrate its operation principle. It is understood that the turf 2 entirely covers the carpet 1 down to one end thereof, substantially at the collecting conduit 300.

Always referring to Figure 4, the carpet 1 has a draining top surface 4 opposite to the laying bottom surface, the latter being not visible as into contact with the bottom0 ground 400. The carpet 1 comprises a plurality of canalizations, of which the canalizations 8 and 8' obtained on the draining top surface 4 are indicated by way of example. The canalizations 8, 8' are adapted to convey and drain water, whose motion is indicated in the figure by arrows f, received from the playing surface and arrived on the draining top surface 4 through the artificial turf 2. Water conveyed inside the5 canalizations is moved by gravity, by means of the slope on which the carpet 1 is positioned, discharged into the collecting conduit 300 and subsequently disposed of. It is understood that there could be other ways to provide canalizations with an inclination, in a manner such as to move by gravity water conveyed therein. For instance, the carpet 1 could be made in a manner such that said canalizations0 themselves have an inclination with respect to the laying bottom surface, and

'^•- ^{■ ■} consequently the carpet 1-^{^}could ^L be positioned on a substantially leveled field.

Alternatively, in order to increase the inclinations and therefore the water draining rate, a combination of the two above-described solutions could be exploited.

Moreover, the canalizations 8, 8' are clearly communicating with an outside5 environment, substantially in correspondence of the side 18 of the sport field 3. Thus, air circulation denoted in figure by arrows F is allowed between the artificial turf 2 and the carpet 1 subject-matter of the present invention. Air circulation, occurring also below the turf 2, contributes to decrease turf drying times, following e.g. any precipitation, improving its longevity. 0 Referring to Figure 5, a carpet 1 according to the present invention is shown in a perspective view. Preferably, the canalizations 8, 8' are substantially rectilinear and parallel therebetween, in order to minimize the path of the water conveyed therein and therefore optimize the drainage times. Moreover, the carpet 1 is preferably arranged on one of the field slopes, so that canalizations are aligned with the short side of the5 field.

Referring to Figure 6A, it is depicted a front view of the carpet along a section line A-A, indicated in Figure 5.

The canalizations 8, 8' obtained on the draining surface 4 have a squared and substantially C-shaped profile. Preferably, to decrease friction caused by onset of vorticity between water and carpet, and thereby improve drainage efficiency, said 5 profile is rounded and substantially U-shaped, as shown in the next figure 6B. Finally, the canalizations are preferably obtained along a longitudinal development on the draining surface 4, with a pair of substantially flared draft angles. In Figure 6C it is indicated, by way of example, the U-shaped rounded profile related to the canalization 8 having two substantially flared draft angles 80 and 80'. Angle flaring improves

10 canalization reaching by water from the artificial turf (not illustrated in Figure).

It will be appreciated that there could be provided a carpet with mixed-type canalizations, i.e., some with a C-shaped squared profile, others with U-shaped rounded profiles and others having substantially flared draft angles. The canalizations will be obtained on the draining top surface, e.g. by milling, or equivalent process. The

15 milling process is well known to the state of the art; therefore it will not be further described.

The carpet 1 is manufactured with a specialized continuous production process, by a mixing of SBR (Styrene Butadiene Rubber) rubber granules and polyurethane resins. In particular, rubber granules and polyurethane resins are selected in a manner such

20 as to give to the carpet water repellence properties, in order to perform the draining

- ^~" — functionf. ancl -impact strength "properties, in order to give to the playing -surface- the- necessary and required elasticity, i.e. the afore-discussed anti-shock effect.

The carpet has a thickness approximately comprised in a range of between 1 mm and

100 mm, and preferably in a range comprised between 2 mm and 50 mm. It is evident

25 that rubber and resin percentages should vary proportionally, depending on the required thickness, in a manner such as to guarantee the required water repellence and elasticity properties of the carpet produced.

The carpet subject-matter of the present invention is produced, as mentioned, by a specialized continuous production process, such that it can be manufactured with

30 dimensions varying according to needs and the specific application scenario.

Preferably, in the example shown herein by way of a non-limiting example, the carpet is made of modules having a first dimension equal to one half of the short side of the field, and a second dimension, i.e. the width, which could range from 1 to 2 meters. Each carpet module has, on at least one side thereof, connecting means adapted to

35 connect it with a module consecutive thereto, in a manner such as to form a modular structure. For instance, referring to Figure 8A, said connecting means could comprise, for a carpet 1 , a portion 35 to be overlapped to a portion 35' of a carpet 1' consecutive thereto. To improve adherence, the portions 35 and 35' could preferably be glued therebetween by, e.g., a resin.

Alternatively, the modular structure could be made simply by laterally arranging 5 side-by-side carpets consecutive therebetween, in the example considered the carpets 1 and 1', as indicated in next Figure 8B. Preferably, should there be less than perfect adherences between the two carpets side-by-side, resin could be applied on their top draining surfaces at an interface 500, in a manner such as to prevent any water leakage.

10 Hereinafter it is described, referring specifically to Figures 7, 8, 9 and 10, a method for making a sport field according to the present invention.

Referring to Figure 7, the method subject-matter of the present invention provides a first step of preparing a bottom surface 66. The bottom surface 66 has, in case the sport field is, e.g., a soccer field, a substantially rectangular plan shape. The

15 step of preparing the bottom surface comprises a step of making thereon at least one slope. In particular, in the example described herein by way of a non-limiting example, two slopes are made, substantially symmetrical with respect to the field center line 31 aligned with the long sides 18 and 18'. Alternatively, the bottom surface could be completely leveled.

20 Referring to Figure 8, the method subject-matter of the present invention

-^■,^;. — rcomprises^'therefore-a "step- of'arranging on theτeadied^~surface-66 a1rleastrσrτe carpet ^• 1 subject-matter of the present invention. In case the bottom surface has been leveled, necessarily the carpet used will have canalizations having an inclination with respect to the laying bottom surface, in order to convey and drain water by gravity.

25 Should there be produced plural carpet modules in the above-highlighted dimensions, they will be arranged on the bottom surface substantially as highlighted in the Figure. The various modules will be connected therebetween in order to form the modular structure as described above. It will be appreciated that the modules arranged on the slope 9 will be arranged so that

30 canalizations obtained thereon converge on the collecting conduit 300, whereas the modules arranged on the slope 9' will be arranged so that canalizations obtained thereon converge on the collecting conduit 300'.

Finally, the method subject-matter of the present invention provides a last step of laying on the modular structure thus formed an artificial turf 2, as shown in Figure 9,

35 until completing the sport field 3, depicted in the last figure 10.

The present invention has been hereto described with reference to a preferred embodiment thereof. It is understood that other embodiments might exist, all falling within the concept of the same invention, and all comprised within the protective scope of the claims hereinafter.

Claims

CLAlMS

1. A carpet (1) adapted to be positioned below an artificial turf (2) of a sport field (3) having a playing surface (6), said carpet (1) having a laying bottom surface (14) for laying and a draining top surface (4) opposite thereto, and being characterized in that it

5 comprises one or more canalizations (8, 8') obtained on said draining surface (4), adapted to convey and drain a fluid received from the playing surface (6) and arrived on said draining surface (4) through said artificial turf (2).

2. The carpet (1) according to the preceding claim, wherein said one or more canalizations (8, 8') have an inclination with respect to the laying bottom surface (14), io in a manner such as to drain said fluid by gravity.

3. The carpet (1) according to claim 1 or 2, adapted to be positioned substantially at a slope (9) of said sport field (3), in a manner such as to drain said fluid by gravity.

4. The carpet (1) according to one of the claims 1 to 3, wherein each canalization (8, 8') of said one or more canalizations (8, 8') is substantially rectilinear.

15 5. The carpet (1) according to any one of the preceding claims, wherein at least one of said one or more canalizations (8, 8') has a substantially C-shaped squared profile.

6. The carpet (1) according to any one of the claims 1 to 5, wherein at least one of said one or more canalizations (8, 8') has a substantially U-shaped rounded profile".

7. The carpet (1) according to one of the preceding claims, wherein each canalization 20 (8, 8¹) of said one or more canalizations (8, 8¹) is obtained on said draining top surface ~ ^{' '} (4) along a longitudinal development thereof with^" a pair of substantially^" flared^" draft angles (80, 80').

8. The carpet (1) according to one of the preceding claims, said one or more canalizations (8, 8') being communicating with an outside environment substantially in

25 correspondence of at least one side (18) of the sport field (3), in a manner such as to allow air circulation between the turf (2) and the carpet (1).

9. The carpet (1) according to one of the preceding claims, manufactured by a mixing of rubber granules and polyurethane resins.

10. The carpet (1) according to the preceding claim, wherein said rubber granules are 30 of SBR type.

11. The carpet (1) according to claims 9 or 10, wherein said rubber granules and said polyurethane resins are selected in amounts such as to give to said carpet (1) water repellence properties.

12. The carpet (1) according to claims 9 to 11 , wherein said rubber granules and said 35 polyurethane resins are selected in amounts such as to give to said carpet (1) impact strength properties.

13. The carpet (1) according to one of the preceding claims, having a thickness substantially comprised between 1 mm and 100 mm.

14. The carpet (1) according to the preceding claim, wherein said thickness ranges substantially between 2 mm and 50 mm.

15. The carpet (1) according to one of the preceding claims, wherein said fluid is water.

16. The carpet (1) according to any one of the preceding claims, further comprising in correspondence of at least one side thereof connecting means (35) adapted to connect it to a carpet (1 ') consecutive thereto, in a manner such as to form a modular structure.

17. A sport field (3) having on a surface (6) thereof an artificial turf (2), said sport field (3) being characterized in that it comprises below said artificial turf (2) at least one carpet (1) according to any one of the preceding claims.

18. The sport field (3) according to the preceding claim, having at least one slope (9) at which it is positioned said at least one carpet (1) according to one of the claims 1 to 16, said slope (9) converging on a respective collecting conduit (300).

19. The sport field (3) according to the preceding claim, having a substantially rectangular plan view and a pair of slopes (9, 9') symmetrical with respect to a center line (31) aligned with a long side (18) of said rectangle.

20. The sport field (3) according to the preceding claim, wherein on each slope (9, 9') of ^"said^* pair of slots (9, 9') it is^~positioned-at least one carpet (1) according to any one of the claims 1 to 16.

21. A method for making a sport field (3), characterized in that it comprises the following steps: • preparing a bottom surface (66); arranging on said bottom surface (66) at least one carpet (1) according to one of the claims 1 to 16; laying on said at least one carpet (1) an artificial turf (2).

22. The method for making a sport field (3) according to the preceding claim, wherein said bottom surface (66) has a substantially rectangular plan shape.

23. The method for making a sport field (3) according to claims 21 or 22, wherein said step of preparing comprises a step of leveling said bottom surface (66).

24. The method for making a sport field (3) according to claims 21 or 22, wherein said step of preparing comprises a step of making at least one slope on said bottom surface (66).