WO2018185002A1

WO2018185002A1 - Prefabricated rollable artificial grass surface and method

Info

Publication number: WO2018185002A1
Application number: PCT/EP2018/058151
Authority: WO
Inventors: Lars Andrén
Original assignee: Drivkraft Andrén
Priority date: 2017-04-04
Filing date: 2018-03-29
Publication date: 2018-10-11
Also published as: EP3385449A1

Abstract

A prefabricated rollable artificial grass surface comprising a turf sheet (1) and a plurality of ribbons (3), representing blades of grass, wherein said plurality of ribbons (3) are arranged on a first side (6a) of the turf sheet (1), characterized in that the prefabricated rollable artifial grass surface further comprises a thermal regulating means in the form of a channel system (2) on a second side (6b) of the turf sheet, wherein said second side (6b) is opposite to said first side (6a) of the turf sheet (1). This prefabricated rollable artificial grass surface provides a simplified solution for the laying of artificial grass surfaces with thermal regulating means.

Description

PREFABRICATED ROLLABLE ARTIFICIAL GRASS SURFACE AND METHOD

Technical field of the invention

The invention relates to artificial grass surfaces. More precisely, the invention relates to artificial grass surfaces with thermal regulating means.

5 Background of the invention

Artificial grass surfaces (turf) are widely used for football pitches, parks, and other recreational grass surfaces. Artificial grass may also be employed for more esthetic purposes, e.g. on roofs. In order to increase the utilization of such an artificial turf, heating can be required to prevent snow 0 accumulation and, for an artificial turf situated in warmer climate, cooling of the turf can also be of interest. For these reasons, thermal regulating means are used in combination with artificial grass surfaces.

WO 03/025288 describes an artificial grass surface including widely spaced rows of ribbons projecting from a flexible backing sheet arranged on5 the ground. Thermal regulating means are attached to the backing sheet in the spaces between the rows of ribbons. A relatively thick infill layer is disposed on the top of the backing sheet, thereby burying the thermal regulating means and holding the ribbons upright. The infill layer may include a growing medium for plant growth. In one embodiment, electric cables are0 integrated into the artificial grass surface in order to heat the surface for de- icing or to maintain plant root warmth. In another embodiment, perforated flexible pipes are integrated into the artificial grass surface to moisten the surface, thereby cooling the surface when the moisture evaporates.

A problem with existing artificial grass surfaces with thermal regulation5 require extensive preparation work in the process of laying the artificial grass surface on a pitch. Summary of the invention

It is an object of the present invention to provide an improved and simplified solution for the laying of artificial grass surfaces with thermal regulating means.

According to a first aspect of the invention, this and other objects are achieved by a prefabricated rollable artificial grass surface comprising a turf sheet and a plurality of ribbons, representing straws of grass, wherein the plurality of ribbons are arranged on a first side of the turf sheet, characterized in that the prefabricated rollable artificial grass surface further comprises a thermal regulating means in the form of a channel system on a second side of the turf sheet, wherein the second side is opposite to the first side of the turf sheet.

"Prefabricated" here means that the thermal regulating means are attached to or integrated with the turf sheet already in the manufacturing process of the artificial grass surface. Such prefabrication enables simplified application of artificial grass surface. Application of the prefabricated rollable artificial grass surface according to the invention simply requires rolling out the grass surface with integrated thermal regulating means onto the pitch, thereby avoiding separate arrangement of a channel system to an artificial turf.

By "channel system" is intended a system of interconnected "closed" channels, i.e. channels which may conduct a flow of heat carrying medium, such as ethanol or brine. After the turf sheets have been rolled out on the surface, the channel systems of different strips of turf maybe connected to form a complete turf channel system which in turn may be connected to a thermal regulating system, such as a heat exchanger or heat reservoir. The heat carrying medium circulating in the channel system will then be able to transfer heat to the turf, e.g. ensuring a frost free turf during cold periods, and to transfer heat away from the turf, e.g. cooling the turf during warm periods with significant sun radiation. The turf surface will thus serve as a radiator, emitting heat during cod periods, and absorbing heat during warm periods. The turf channel system may be connected to a heat reservoir, i.e. a heat storage or heat buffer, allowing storage of sun energy collected by the heat carrying medium in the channel system. The heat storage then preferably has a storage channel system which is connected to the turf channel system. A pump, and preferably a circulation control system, may be arranged to circulate a heat carrying medium in the turf channel system and storage channel system, so as to transfer heat energy from the turf to the storage and vice versa.

The heat storage may be provided in layers of matter in or underneath the turf. Energy stored in such a heat storage may be used at another time to heat the artificial turf. It may also be used in a separate heating system, e.g. as energy source for a heat exchanger used for indoor heating.

The channel system of the prefabricated reliable artificial grass surface may be formed in one piece. Furthermore, the channel system may be woven onto the turf sheet or alternatively be glued onto the turf sheet. The channel system and the turf sheet may also be formed in one piece as a single layer.

According to an embodiment of the invention, the channel system comprises a first set of parallel flexible tubes along the length of the prefabricated reliable artificial grass surface. This is a simple form of channel system, which is easy to manufacture, e.g. by extrusion.

The channel system may further comprise a second set of parallel flexible tubes along the width of the prefabricated reliable artificial grass surface, wherein the second set of parallel flexible tubes connects the first set of parallel flexible tubes. Such transversal tubes may serve to equalize pressure in the system, and serve to improve flow through the system.

According to another embodiment of the invention, the channel system comprises a meander shaped flexible tube along the length of the

prefabricated reliable artificial grass surface. This embodiment enables for cutting of the prefabricated reliable artificial grass surface where the tube tangent the side of the prefabricated reliable artificial grass surface without cutting the tube itself, then turning the continuation of the prefabricated reliable artificial grass surface around this side to let the tube continue through the next strip. Alternatively, main tubes along one side or two opposite sides of the laid artificial grass surface can be used to connect the tubes of the strips of prefabricated rollable artificial grass surface.

The prefabricated rollable artificial grass surface may further comprise a supporting base of elastic material on the second side of the turf sheet. The supporting base of elastic material may be sandwiched between the turf sheet and the channel system, or alternatively the channel system may be sandwiched between the turf sheet and the supporting base.

Using a supporting base of elastic material in the prefabricated rollable artificial grass surface helps achieving a desired firmness of the pitch without requiring additional preparation work on the ground. It also helps protecting the channel system, which can be placed in cut-outs in the supporting base and thus not be exposed to excessive forces from the load on the laid artificial grass surface.

According to another aspect of the invention, there is provided a method of laying an artificial grass surface, the method comprising the steps of: providing a prefabricated rollable artificial grass surface according to the first aspect of the invention, arranging strips of the prefabricated rollable artificial grass surface along each other so as to cover said area, and connecting channel systems of each section so as to form one aggregate channel system for the entire area.

The connection of channel systems may be accomplished by

connecting main tubes to a set of parallel flexible tubes of each strip of the artificial grass surface.

If the channel system includes a meander shaped tube, the connection can include separating a section of the meander shaped tube from the channel system, and orienting a subsequent strip next to a preceding strip so that said section bridges the channel systems of each strip.

It is noted that the invention relates to all possible combinations of features in the claims.

Brief description of the drawings The present invention will be described in more detail with reference to the appended drawings, showing currently preferred embodiments of the invention.

Fig. 1 is a partially exploded perspective view of a cross section of the prefabricated rollable artificial surface according to an embodiment of the invention.

Fig. 2 is a cross section of the prefabricated rollable artificial surface according to another embodiment of the invention.

Fig. 3 is a cross section of the prefabricated rollable artificial surface according to yet another embodiment of the invention.

Fig. 4 is a schematic view of covering an area with a prefabricated rollable artificial surface according to an embodiment of the invention.

Fig. 5a - 5b is a schematic view of covering an area with a

prefabricated rollable artificial surface according to another embodiment of the invention.

Fig. 6 schematically illustrates manufacturing of a prefabricated artificial surface according to an embodiment of the invention.

As illustrated in the figures, the sizes of layers and regions may be exaggerated for illustrative purposes and, thus, may be provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout.

Detailed description of the invention

Fig. 1 shows a prefabricated rollable artificial grass surface according to an embodiment of the invention. The prefabricated rollable artificial grass surface according to this embodiment includes an artificial grass layer 7, including a turf sheet 1 , with a plurality of ribbons 3 extending from a first side 6a of the turf sheet 1 . The first side 6 of the turf sheet 1 is to be interpreted as the side facing up when the artificial grass surface is laid. On a second side 6b of the turf sheet 1 , opposite to the first side 6a and consequently also the side facing down when the artificial grass surface is laid, is provided a channel system 2, here including a base layer 4 and a set of flexible tubes 9. It is noted that the channel system 2 alternatively be constructed as a web of tubes 9 without a joining base layer or as individual tubes separated from each other.

The turf sheet 1 is suitably made of such a material, and has such a thickness that it can withstand the force and wear that is to be asserted on the artificial grass surface, for instance from maintenance vehicles and studded shoes, and should furthermore be proof to any ultraviolet light and suited to withstand any temperatures that occur in the local environment. An example of a material that can be used for the turf sheet 1 is polypropylene fabric, and the fabric may further be woven or needle punched to provide good drainage. However, any flexible material that allows for rolling up and rolling out the prefabricated reliable artificial grass surface can be used according to the invention. For instance, ethylene propylene diene monomer rubber or polyvinyl chloride are examples of other materials that can be used.

The ribbons 3 are made from any material that provides suitable softness and abrasion resistance to the ribbons 3, such as for instance, but not limited to, polyethylene or polypropylene. The ends of the ribbons 3 might interweave each other and might be fibrillated, split or frayed to further simulate the appearance of natural grass. The artificial grass layer 7 can for example be a conventional artificial grass surface, such as FieldTurf® 360 XL 42-13.

The channel system is intended to conduct and circulate a suitable heat carrying medium, and should thus be made of an appropriate material for this purpose. A simple example of heat carrying medium is water, but depending on the climate conditions, it may be required to add suitable substances to avoid boiling or freezing. The channel system 2 can for instance be made out of a polymer material that withstands the use of water with ethanol, ethylene glycol, propylene glycol or chlorine. The channel system 2 should also be able to withstand the use of a solution of salt and water, such as for instance brine. The tubes of the channel system 2 should be flexible in order to enable for it to hold for the process of rolling up and rolling out the prefabricated reliable artificial grass surface. Another benefit of having flexible tubes in the tube channel system 2 is that it reduces the risk of frost weathering in the channel system 2.

In one example, the channel system is extruded, in which case the tubes preferably extend in the longitudinal direction of the surface (i.e. along its length). Other examples include more complicated channel systems, e.g. including also tubes extending across the surface, connecting the longitudinal tubes. According to one embodiment, the channel system 2 is of the type used for solar heating of pool water.

The channel system 2 is attached to the artificial grass layer 7 by appropriate means, e.g. adhesive, welding, stitching, etc. As one example, the ribbons 3 are used to stitch the turf sheet 1 to the base layer 4 of the channel system 2.

It is noted that the turf sheet 1 and channel system 2 are here indicated as separate parts which are attached to each other. However, it is possible that the turf sheet is simply formed by the base layer 4 of the channel system

2. In that case, the artificial grass ribbons 3 are attached, e.g. stitched, directly to the base layer 4, e.g. between the channels.

The prefabricated reliable artificial grass surface is laid on the ground

5, where the ground might additionally be prepared with an isolating layer in order to improve the thermal regulation in the prefabricated reliable artificial grass surface. Alternatively, an isolating layer can be attached directly to the prefabricated reliable artificial grass surface in the fabrication process to further simplify the laying of artificial grass surface.

After laying the prefabricated reliable artificial grass surface on the pitch, there might be provided an additional infill layer of particulate material upon the turf sheet 1 . Such an infill layer might for instance consist of sand granules, resilient rubber granules or a mixture thereof. The particulate material used should in this case also provide sufficient heat dissipating for enabling the channel system 2 to thermally regulate the surface of the pitch when the channel system 2 is connected to a suitable thermal regulating system. In Fig. 2 an embodiment is shown where a supporting base 8 is glued to the second side 6b of the turf sheet 1 and the channel system 2 is glued to the side to be facing down of the supporting base 8. The channel system 2 is here attached beneath the supporting base, however the channel system 2 can alternatively lie within the supporting base 8 or be integrated directly into the turf sheet 1 to form a single layer, with or without an underlying supporting base 8. Fig. 3 shows an alternative embodiment where the channel system 2 is attached (e.g. glued) directly to the turf sheet 1 , while the supporting base is attached (e.g. glued) to the other side of the channel system 2. It should be noted that any means of attaching the layers of the prefabricated rollable artificial grass surface can be used according to the invention.

Referring to both Fig. 2 and Fig. 3, the supporting base 8 preferably has cut-outs for receiving the tubes of the channel system 2 when attaching the supporting base 8 and the channel system 2 to each other. The material for the supporting base 8 can be chosen from a wide variety of elastic materials, however it is advantageous to use a material that can hold at least for the life span of the turf sheet 1 . The thickness of the supporting base 8 can be chosen based on the estimated load on the artificial grass surface to be able to properly protect the channel system 2, typically between 8 and 40 mm. Referring to Fig 3, the material of the supporting base 8 should be of sufficient heat conduction for the channel system 2 to be able to regulate the temperature of the turf sheet 1 , when the channel system 2 is connected to a suitable thermal regulating system. In other words, the channel system should allow transfer of heat between a heat carrying medium flowing in the channel system and the turf sheet.

Fig. 4 shows a schematic view of one example of covering an area with strips 10 of a prefabricated rollable artificial grass surface according to an embodiment of the invention. The contours of the strips 10 are here indicated by dashed lines. The prefabricated rollable artificial grass surface here comprises a first set of parallel flexible tubes 12 along the length of the strip 10 and a second set of parallel flexible tubes 1 1 along the width of the strip. When the strips have been arranged on the area to be covered by artificial grass, the open ends of the tubes 12 are connected by main tubes 13 extending along the ends of the strips 10. Hereby, a closed system of connected channels is created (only open at the ends of the main tubes 13), which in turn may be connected to a thermal regulating system such as an heat exchanger (not shown) or a heat storage (not shown) provided with a storage channel system. By connecting a pump to circulate the medium in the turf channel system and storage channel system, heat may be transferred from the turf into a heat storage, and back to the turf from the heat storage. The pump is preferably controlled by a suitable control system, e.g. adapted to maintain a flow rate throughout the channel system based on a required need for cooling/heating of het turf. The control system may be connected to appropriate sensors, for detecting e.g. ambient temperature, turf temperature, etc.

The illustration shows an embodiment where the second set of parallel flexible tubes 12 has two parallel tubes connecting the first set of parallel tubes, however both the first set of parallel flexible tubes 1 1 and the second set of parallel flexible tubes 12 might comprise any plurality of parallel tubes according to the invention.

Fig. 5a - 5b show a schematic view of a further example of covering an area with strips 10 of a prefabricated rollable artificial grass surface according to an embodiment of the invention. The prefabricated surface here has a channel system comprising a meander shaped flexible tube 14 extending back and forth across the artificial grass surface. In this embodiment, the roll is again cut into strips 10a 10b. However, in this case, a section 15 forming a bend of the meander shaped tube 14 is separated from the channel system and left intact. This allows a subsequent strip 10a to be oriented next to a preceding strip 10b with the section 15 bridging the channel systems of each strip 10a, 10b.

Alternatively, main tubes along one side or two opposite sides of the laid artificial grass surface pitch can be used to connect the tubes of the strips of prefabricated rollable artificial grass surface, similar to the main tubes 13 shown in Fig. 4.

In both cases, however, the end result should, just as in figure 4, be a channel system which may be connected to a thermal regulating system such as an heat exchanger (not shown) or a heat reservoir (not shown), in which a heat carrying medium may be circulated by means of a pump.

Referring to Fig. 4 and 5, the distance between the parallel tubes depends on what power is needed from the thermal regulating means (e.g heat exchanger), the dimensions of the channel system and the depth at which the channel system lies. Normally, the distance between the parallel tubes is between 150 and 250 mm.

Fig. 6 illustrates a way of producing a prefabricated rollable artificial grass surface according to one embodiment of the invention. A turf sheet 1 is here attached to a channel system 2 to form one integrated piece using two rollers. The layers may be welded, glued, or attached by any other means, including suitable heat and pressure. In the illustrated case, the ribbons 3 are already attached to the turf sheet 1 . However, the ribbons of the turf sheet may also be attached after the rollers, and possibly used to stitch the turf sheet 1 to the channel system 2.

The person skilled in the art realizes that the present invention by no means is limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the structure of the channel system may be designed in a number of different ways.

Additionally, variations to the disclosed embodiments can be understood and affected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

Claims

C L A I M S

1 . A prefabricated reliable artificial grass surface comprising a turf sheet (1 ) and a plurality of ribbons (3), representing blades of grass, wherein said plurality of ribbons (3) are arranged on a first side (6a) of the turf sheet

(1 ) , characterized in that the prefabricated reliable artificial grass surface further comprises a thermal regulating means in the form of a channel system

(2) on a second side (6b) of the turf sheet (1 ), wherein said second side (6b) is opposite to said first side (6) of the turf sheet (1 ).

2. The prefabricated reliable artificial grass surface according to claim 1 , wherein said channel system (2) is formed in one piece.

3. The prefabricated reliable artificial grass surface according to claim 2, wherein the channel system (2) is extruded.

4. The prefabricated reliable artificial grass surface according to any of the preceding claims, wherein said channel (2) system is woven to said turf sheet (1 ) by the ribbons (3).

5. The prefabricated reliable artificial grass surface according to any of the preceding claims, wherein said channel system (2) is glued to said turf sheet (1 ).

6. The prefabricated reliable artificial grass surface according to any of the preceding claims, wherein the channel system (2) comprises:

a first set of parallel flexible tubes (1 1 ) along the length of the prefabricated reliable artificial grass surface.

7. The prefabricated reliable artificial grass surface according to claim

6, further comprising a second set of parallel flexible tubes (12) along the width of the prefabricated reliable artificial grass surface, wherein the second set of parallel flexible tubes (12) connects the first set of parallel flexible tubes (1 1 ).

8. The prefabricated rollable artificial grass surface according to any of claims 1 -5, wherein the channel system (2) comprises a meander shaped flexible tube (14) along the length of the prefabricated rollable artificial grass surface.

9. The prefabricated rollable artificial grass surface according to any of the preceding claims, further comprising a supporting base (8) of elastic material on the second side (6b) of said turf sheet (1 ).

10. The prefabricated rollable artificial grass surface according to claim 8, wherein said supporting base (8) of elastic material is sandwiched between said turf sheet (1 ) and said channel system (2).

1 1 . The prefabricated rollable artificial grass surface according to claim 8, wherein said channel system (2) is sandwiched between said turf sheet (1 ) and said supporting base (8).

12. An artificial grass turf with integrated heat regulation, comprising: a turf including one or several prefabricated artificial grass surfaces according to one of the preceding claims arranged on a suitable support, wherein the channel systems of each prefabricated artificial grass surface have been interconnected to form one integrated turf channel system,

a heat storage including a storage channel system, which storage channel system is connected to the turf channel system, and

a pump for circulating a heat carrying medium in said turf channel system and said storage channel system, thereby transferring heat between from said turf to said heat storage and/or from said heat storage to said turf.

13. A method of laying an artificial grass surface on an area, the method comprising the steps of:

providing a prefabricated rollable artificial grass surface according to one of the preceding claims;

arranging strips (10; 10a, 10b) of said prefabricated rollable artificial grass surface along each other so as to cover said area; and

connecting channel systems of each strip so as to form one aggregate channel system for the entire area.

14. The method according to claim 13, wherein the prefabricated rollable artificial grass surface is according to claim 6 or 7, and wherein the step of connecting channel systems comprises:

connecting main tubes (13) to the first set of parallel flexible tubes (12) of each strip (10) of the artificial grass surface.

15. The method according to claim 13, wherein the prefabricated rollable artificial grass surface is according to claim 8, and wherein the step of connecting channel systems comprises:

separating a section (15) of the meander shaped tube (14) from the channel system; and

orienting a subsequent strip (10a) next to a preceding strip (10a) so that said section (15) bridges the channel systems of each strip (10a, 10b).