ARTIFICIAL TURF INFILL MATERIAL

Abstract

This invention provides an artificial turf infill material including a microporous zeolite mineral having a selected gain size smaller than 5 mm and a porosity between 15% and 30%, where the microporous zeolite mineral has a grain size distribution as follows: 90% to 100% of the grains have a size in the range 0.4 mm to 5.0 mm.

Claims

1. An artificial turf infill material comprising a microporous zeolite mineral having a selected gain size smaller than 5 mm and a porosity between 15% and 30%, wherein the microporous zeolite mineral has a grain size distribution as follows: 90% to 100% of the grains have a size in the range 0.4 mm to 5 mm.

2. The infill material of claim 1, wherein 0.6% of the mineral at most is not retainable on a 100 mesh screen.

3. The infill material of claim 1, the microporous zeolite mineral having a hardness between 3 and 4 on the Mohs scale.

4. The infill material of claim 1, wherein the moisture level in the mineral is smaller than 6%.

5. An artificial turf infill material comprising a microporous zeolite mineral having a selected grain size between 0.15 mm and 19 mm and a maximum specific surface area between 15 m.sup.2/g and 30 m.sup.2/g.

6. An artificial turf including the material, according to claim 1, as an artificial turf infill.

7. A method for forming an artificial turf infill material, the method comprising: providing a zeolite ore; reducing the zeolite ore into smaller zeolite fractions; selecting from the zeolite fractions a microporous zeolite mineral having a grain size between 0.15 mm and 19 mm and a maximum specific surface area between 15 m.sup.2/g and 30 m.sup.2/g, thereby providing the artificial turf infill material.

8. An artificial turf comprising an artificial turf carpet with a pile and artificial turf infill, wherein the artificial turf carpet comprises a backing; wherein the artificial turf carpet further comprises artificial grass fibers, wherein the artificial grass fibers are tufted into the backing, wherein the artificial grass fibers form the pile, wherein the artificial grass fibers are secured to the backing, wherein the artificial turf infill comprises the artificial turf infill material according to claim 1.

9. The artificial turf of claim 8, wherein the artificial turf further comprises a sprinkler system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In the following embodiments of the invention are explained in greater detail, by way of example only, making reference to the drawings in which:

[0047] FIG. 1 is a flowchart of a method for forming an artificial turf infill material

[0048] FIG. 2 is a flowchart of an example method for selecting a microporous zeolite mineral from the zeolite ore;

[0049] FIG. 3 is a flowchart of another example method for selecting a microporous zeolite mineral from the zeolite ore;

[0050] FIG. 4A illustrates an example of an artificial turf;

[0051] FIG. 4B illustrates a further example of an artificial turf;

[0052] FIG. 4C illustrates a further example of an artificial turf; and

[0053] FIG. 5 illustrates an example of an artificial turf which incorporates a sprinkler system.

DETAILED DESCRIPTION

[0054] Like numbered elements in these figures are either equivalent elements or perform the same function. Elements which have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.

[0055] FIG. 1 is a flowchart of a method for forming an artificial turf infill material. The infill material may be included in artificial turfs as described with reference to FIGS. 4A-5.

[0056] In step 101, a zeolite ore may be provided. The zeolite ore is a naturally occurring solid material. The zeolite ore has a porosity between of 15% and 20%. The term “porosity” refers to the volume fraction of void space in a porous article. The zeolite phase of the zeolite ore may comprise one or more of the group consisting of clinoptilolite, mordenite, or other naturally occurring zeolite minerals.

[0057] The zeolite ore may be provided for example as follows. A zeolite deposit is stripped of overburden and stockpiled for use in subsequent mine reclamation. The resulting exposed ore body is drilled to depths between 12 and 14 feet. The drill holes are loaded with an explosive charge that degenerates upon use, leaving no residue in the zeolite ore. From the mine pit, the zeolite ore is hauled by dump truck to the crude ore stockpile at a processing mill.

[0058] In step 103, a microporous zeolite mineral may be selected from the zeolite ore. The selection may be performed using a selection criterion involving the specific surface area of the mineral. The selection criterion may refer to one or more rules on the specific surface area. The selected microporous zeolite mineral has for example a porosity between 15% and 20%.

[0059] For example, the selection of step 103 comprises a selective recovering or obtaining of the microporous zeolite mineral having a predefined specific surface area from the zeolite ore. The specific surface area constitutes an important criterion that is involved in the determination of the quality of a zeolite mineral since the nature of the specific surface area enables a decisive characteristic for the overall usage of zeolite in numerous technical components and products. For example, a specific surface area which is too high may render the release of water under ambient temperature very slow or inexistent.

[0060] In one example, the selection criterion requires that the specific surface area is smaller than a predetermined maximum specific surface area. The maximum specific surface area of the mineral may for example be determined as the surface specific area that enables the water in the mineral to release, under an ambient temperature, at a predefined minimum rate. For example, for a specific surface area equal or higher than 40 m.sup.2/g the water may only release under temperatures which are higher than the maximum ambient temperatures. Those high temperatures require the use of an oven. The present method may be advantageous as the maximum surface specific area that is selected enables the water to release under ambient temperatures e.g., between 40 and 60 F. The selected specific surface area may for example be 20 m.sup.2/g for a porosity of 15% to 20%.

[0061] In another example, the maximum specific surface area is chosen such that at most 0.6% of the mineral is not retainable on a 100 mesh screen e.g., 99.4% of the mineral has a grain size higher than 0.15 mm. This may have the advantage of reducing the amount of dust in addition to enabling a progressive release of the water for an optimal cooling of the artificial turf. Reducing the amount of dust may be beneficial for improving the safety of the product as regards the protection of the respiratory system of users of the artificial turf.

[0062] The selected microporous zeolite mineral may be used as the artificial infill material. In on example, the artificial infill material may consist of the selected microporous zeolite mineral. In another example, the artificial infill material may comprise the selected microporous zeolite mineral in addition to other infill materials.

[0063] FIG. 2 is a flowchart of an example method for selecting a microporous zeolite mineral from the zeolite ore (e.g., the zeolite ore provided in step 101) using a grinding unit. The grinding unit is configured for performing the grinding and screening of zeolite materials. The grinding unit may have parameters for controlling its function. The parameters may for example comprise the reduction ratio of the grinding unit, the number of times the screening is to be repeated in the screening step; the exciting force causing the vibration of the screening unit; inclined and/or horizontal screening.

[0064] In step 201, a zeolite grain size that corresponds to the maximum surface specific area may be determined. The grain size of the microporous zeolite mineral is determined such that the resulting specific surface area of the mineral is smaller than the maximum specific surface area.

[0065] Naturally, the specific surface area of the microporous zeolite mineral varies with its structure. For example, the finer the mineral is, the larger the specific surface area is (i.e., the smaller the grain size is, the larger the specific surface area is).

[0066] For example, the specific surface area of the microporous zeolite mineral may not exceed a minimum specific surface area. The minimum specific surface area may be the smallest possible specific surface area. In this case, the determined grain size may be the lower limit of a range of sizes, wherein the upper limit of the range may be determined using the minimum specific surface area. The microporous zeolite mineral may for example have a grain size between 0.5 mm and 1.2 mm or between 0.9 mm and 1.2 mm, for a maximum surface specific surface area of 21 m.sup.2/g (e.g., the selected specific surface area may be 20 m.sup.2/g).

[0067] In step 203, the zeolite ore may be reduced into smaller zeolite fractions. FIG. 3 shows an example method for reducing the zeolite ore into smaller fractions. The zeolite fractions may for example have a maximum size of ⅝ inch. In order to obtain that maximum size for the fractions, the reducing of the zeolite ore may comprise in addition to crushing the zeolite ore, a sieving or screening step, wherein in the screening step the crushed zeolite ores are screened with series of sieves. For example, the series of sieves may comprise sieves having sieve sizes ranging from about a minus 14 mesh (1.41 mm) to about a plus 40 mesh (0.42 mm).

[0068] In step 205, parameters of the grinding unit may be set in accordance with the determined grain size of step 201. For example, the reduction ratio of the grinding unit may be set such that the grinding unit may provide or output the zeolite fractions grains having as a maximum size the determined grain size.

[0069] In one example, before performing the grinding step 207, the zeolite fractions resulting from step 203 may be dried in a dryer. This may have the advantage of reducing the amount of dust in the resulting microporous zeolite mineral.

[0070] In step 207, the zeolite fractions may be ground in the grinding unit. The term “grinding” encompasses processes like cutting, chopping, crushing, milling, pulverizing, and the like.

[0071] After grinding the zeolite fractions, the resulting zeolite material may be screened in step 208, resulting in groups of zeolite grains, wherein each group has a respective minimum grain size. The screening may for example be performed using series of sieves having sieve sizes ranging from about a minus 14 mesh (1.41 mm) to about a plus 40 mesh (0.42 mm). The screening may be a vibratory-type screening.

[0072] In one example, up to six or more different fractions can be separated in one screening process. This may for example be done using multiple sieve decks positioned on top of each other in a classification range such as a range of 0.1 mm to 1.5 mm or alternatively in a classification range such as a range of 0.1 mm to 3.0 mm, or alternatively in a classification range such as a range of 0.1 mm to 4.0 mm, or alternatively in a classification range such as a range of 0.1 mm to 5.0 mm.

[0073] The maximum grain size of each group of the groups may be compared with the determined grain size of step 201. In case (inquiry 209) the minimum grain size of a group of the groups is higher than the determined grain size, step 208 or steps 207-208 may be repeated. Otherwise, the group may be selected and stored in step 211 as part of the selected microporous zeolite mineral.

[0074] For example, the method may end if the selected microporous zeolite mineral reaches a predefined amount or if the input ore is completed.

[0075] FIG. 3 illustrates the process of selecting a microporous zeolite mineral from a zeolite ore (e.g., zeolite ore of step 101) in accordance with another example of the present disclosure. FIG. 3 shows a crushing unit 301 and a grinding unit 302, wherein the zeolite ore is first processed at the crushing unit 301 and the resulting material is input to the grinding unit 302 for further processing.

[0076] Before processing the zeolite ore in the crushing unit 301, the zeolite ore may for example be obtained as follows. A zeolite deposit is stripped of overburden and stockpiled for use in subsequent mine reclamation. The resulting exposed ore body is drilled to depths between 12 and 14 feet. The drill holes are loaded with an explosive charge that degenerates upon use, leaving no residue in the zeolite ore. From the mine pit, the zeolite ore is hauled by dump truck to the crude ore stockpile at a processing mill.

[0077] The zeolite ore is fed in step 31 through a grizzly 303 with 16″×16″ opening, the output ore of the grizzly 303 travels in step 32 via a first conveyer into a jaw crusher 305 where the output ore of the grizzly 303 is reduced to a 4 inch size resulting in 4 inch ore. The 4 inch ore travels in step 33 via a second conveyor to a double deck Nordberg screen 307 with a ⅝ inch screen on the top deck. The resulting output of the double deck Nordberg screen 307 is a minus ⅝ inch material and plus ⅝ inch material.

[0078] The minus ⅝ inch material travels in step 34 to a third conveyor toward the grinding unit 302 via a dryer 311. The plus ⅝ inch material travels back in step 35 via a fourth conveyor to a cone crusher 309 which reduces the plus ⅝ inch material to at least ½ inch material. The ½ inch material then returns in step 37 to the Nordberg screen 307 via the second conveyor.

[0079] From the third conveyor, the zeolite material output of the Nordberg screen 307 travels in step 34 to a propane fueled rotary kiln dryer 311 where it is heated at 250° C., reducing moisture to 5%, and fed in step 38 to the grinding unit 302.

[0080] The zeolite material is conveyed in step 38 from the dryer 311 via a fifth conveyor to an impact crusher 313 and five-decked Midwestern screens 315. From the screens 315 the zeolite is sized and conveyed in step 39 to a sixth conveyor for packaging e.g. in super sacks 320 ready to ship or the zeolite is returned in step 40 via a seventh conveyor to the impact crusher 313 and which is returned to the Midwestern Screens 315. At the Midwestern screens 315, the products are sized according to customer specifications and either sent to finished product handling.

In the finished product handling process: a. the material is either sent to bulk storage silos for direct truck loading or b. The material is sent to packaging silos where it is packaged in customer specified bags and palletized, wrapped, and stored in warehouse for truck pick up.

[0081] The following table gives example properties of the selected microporous zeolite mineral of the present method.

TABLE-US-00001 Parameter Values Granulometry 14 × 40 mesh (0.42-1.39 mm) Particle size distribution 14 mesh (1.39 mm)  0.9% 20 mesh (0.84 mm) 39.0% 30 mesh (0.59 mm) 27.0% 40 mesh (0.42 mm) 21.0% 100 mesh (0.15 mm) 10.0% <100 mesh  0.6% color/Brighthness White/85 Hardness 3 Porosity 15-20% Arsenic total <4 mg/kg sec Level of humidity   ≤6%

[0082] The values of the parameters, particle size or grain size, color, hardness, arsenic total and level of humidity, listed in the table are central values. However, each parameter of these parameters may have a value in the range defined by the central value, ±10%, ±5% or ±3% of the central value. These values may for example enable us to obtain a specific surface area of 20 m.sup.2/g.

[0083] FIG. 4A shows an example of an artificial turf 400A. The artificial turf 400A comprises an artificial turf carpet 402. The artificial turf carpet comprises a backing 404 and also artificial grass fibers 406. The artificial grass fibers 406 are tufted into the backing 404 and are secured 408 to the backing 404. The artificial turf fibers 406 form a pile 403. The artificial turf carpet 402 is resting on a ground 410 or surface. Between and distributed between the artificial grass fibers 406 and within the pile 403 is an artificial turf infill 412. The infill artificial turf infill 412 is shown as having a cylindrical shape; however it may have other shapes. For example, the shape of the microporous zeolite mineral may be a spherical shape. In this example the artificial turf infill 412 is made from at least the selected microporous zeolite mineral 414. In on example, the artificial infill material may consist of the selected microporous zeolite mineral. In another example, the artificial infill material may comprise the selected microporous zeolite mineral in addition to other infill materials.

[0084] FIG. 4B shows a further example of an artificial turf 400B. The artificial turf 400B is similar to the artificial turf 400A shown in FIG. 4A except there is additionally a sand layer 420 between the artificial turf infill 412 and the backing 404. The use of the sand layer 420 may be advantageous because it may help to hold the artificial turf carpet 402 in place. It may also have the technical benefit that the sand layer 430 works in conjunction with the artificial turf infill 412 to regulate the amount of water on the surface of the artificial turf 400B. For example if it rains or if water is sprayed onto the surface of the artificial turf 400B the composite infill components 414 may rapidly absorb and saturate with water. The sand layer 420 may then aid in draining away excess water and preventing it from standing on the surface of the artificial turf 400B.

[0085] FIG. 4C shows a further example of an artificial turf 400C. The artificial turf 400C is similar to the artificial turf 400B shown in FIG. 4B with the addition of several additional layers. Directly underneath the backing 404 is an elastic layer 432. The elastic layer 432 may for example be a mat or other material such as sand and elastomeric granulate or a mixture thereof that readily absorbs shock. The elastic layer 432 is optional. The backing 404 and/or the elastic layer 432 may have holes or may be porous so that water that is standing on the artificial turf 400C can be drained away. The elastic layer 432 is directly sitting on a drainage system 430. The drainage system 430 may comprise granulate material, drainage tiles, drainage pipes or other system for rapidly draining water off the surface of the artificial turf 400C. The artificial turf depicted in FIG. 4C may have superior qualities when water is used to cool or improve sliding properties. Water that initially goes on the surface may readily be absorbed by the composite infill components 414 that make up the artificial turf infill 412. When they have filled with water excess water may then go into and possibly be stored in the sand layer 420. When the sand layer 420 is saturated it may drain through the backing 404 and/or the elastic layer 432 into the drainage system 430.

[0086] FIG. 5 shows a further example of the artificial turf e.g., 400A. In this example an automatic sprinkler system 500 has been integrated into the artificial turf 400A. The sprinkler 500 is depicted as spraying water 502 on an upper surface of the artificial turf 400A. The use of the sprinkler may be beneficial in combination with the artificial turf as it may provide an integrated watering system for an optimal watering of the artificial turf.

LIST OF REFERENCE NUMERALS

[0087] 31-40 method steps [0088] 101-103 method steps [0089] 201-211 method steps [0090] 301 crushing unit [0091] 302 grinding unit [0092] 303 grizzly [0093] 305 jaw crusher [0094] 307 Nordberg screen [0095] 309 cone crusher [0096] 311 dryer [0097] 313 impact crusher [0098] 315 Midwestern screens [0099] 320 sack [0100] 400A artificial turf [0101] 402 artificial turf carpet [0102] 403 pile [0103] 404 backing [0104] 406 artificial grass fibers [0105] 408 secured to backing [0106] 410 ground [0107] 412 artificial turf infill [0108] 414 composite infill component [0109] 400B artificial turf [0110] 420 sand layer [0111] 400C artificial turf infill [0112] 432 elastic layer [0113] 430 drainage system [0114] 500 sprinkler system [0115] 502 spraying water.