METHOD AND APPARATUS FOR SEPARATING SYNTHETIC TURF INFILL MATERIAL

Abstract

A method of separating infill material (105) of synthetic turf is disclosed. The infill material (105) comprises sand (155), rubber (165) and fibres (135). The method comprises combining the infill material (105) with water (106) to form an infill slurry (110), and separating one or more of the sand (155), rubber (165) and fibres (135) from the infill slurry (105). A hydrocyclone (104) may be used to separate the infill slurry (105) into a fibre slurry (107) and a sand/rubber slurry (111). An separation unit (200) for carrying out the method is also disclosed.

Claims

1. A method of separating infill material of synthetic turf, the infill material comprising sand, rubber and fibres, the method comprising combining the infill material with water to form an infill slurry, and separating one or more of the sand, rubber and fibres from the infill slurry.

2. The method according to claim 1, wherein a hydrocyclone is used to separate the infill slurry into a fibre slurry and a sand/rubber slurry.

3. The method according to claim 2, wherein a density separator is used to separate sand and rubber from the sand/rubber slurry; and wherein said density separator is selected from the group consisting of a fluidised bed separator, a spiral separator, an upflow classifier, and a separation jig.

4. The method according to claim 3, further comprising the step of adding water to the sand/rubber slurry after it has left the hydrocyclone and before it has entered the density separator.

5. The method according to claim 2, wherein the majority of the water which enters the hydrocyclone leaves the hydrocyclone in the fibre slurry.

6. The method according to claim 1, wherein the water component of the fibre slurry is recycled for use elsewhere in the method.

7. The method according to claim 1, further comprising the step of feeding the infill material into a trash screen to separate debris from the infill material before combining the infill material with water.

8. The method according to claim 1, wherein the infill material is loaded into a hopper and the infill material is fed from the hopper to the trash screen.

9. The method according to claim 1, wherein the infill material is removed from a synthetic turf pitch prior to being combined with the water.

10. The method according to claim 9, wherein the method takes place on the site of the synthetic turf pitch.

11. An apparatus for separating sand and rubber from synthetic turf infill material comprising sand, rubber and fibres, the apparatus comprising a compartment for receiving infill material and combining the infill material with water to produce an infill slurry, and a separator configured to separate one or more of (i) sand, (ii) rubber and/or (iii) fibres from the infill slurry.

12. The apparatus according to claim 11, comprising a first separator configured to separate the infill slurry into a fibre slurry and a sand/rubber slurry and a second separator configured to separate the sand/rubber slurry into produce a sand slurry and a rubber slurry.

13. The apparatus according to claim 12, wherein the first separator is a hydrocyclone.

14. The apparatus according to claim 12, wherein the second separator is a density separator.

15. The apparatus according to claim 14, wherein the density separator is a spiral separator.

16. The apparatus according to claim 12, wherein the apparatus comprises a trash screen for removing debris from the infill material and infill material passes through the trash screen and into the compartment.

17. The apparatus according to claim 11, wherein the apparatus is provided in a single unit.

18. The apparatus according to claim 17, wherein the unit further comprises a hopper, a sand screen, a rubber screen, a pump, and/or piping.

19. The apparatus according to claim 11, wherein the apparatus is contained within the footprint of a standard 20 ft shipping container.

20. The method according to claim 1, further comprising using an apparatus having a compartment for receiving infill material and combining the infill material with water to produce an infill slurry, and a separator configured to separate one or more of (i) sand, (ii) rubber and/or (iii) fibres from the infill slurry; and transporting said apparatus to a site of a synthetic turf surface.

Description

DESCRIPTION OF THE DRAWINGS

[0067] Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which:

[0068] FIG. 1 shows a process flow diagram of an example method according to the invention.

[0069] FIG. 2 shows a schematic side view of the separation unit according to a first example embodiment of the invention, when in a stowed configuration;

[0070] FIG. 3 shows a side view of the separation unit of FIG. 2, when in an operational configuration;

[0071] FIG. 4 shows a plan view of the separation unit of FIG. 2, when in the stowed configuration;

[0072] FIG. 5 shows an end view of the separation unit of FIG. 2, when in the stowed configuration;

[0073] FIG. 6 shows a side view of the separation unit of FIG. 2, when in the operational configuration;

[0074] FIG. 7 shows a side end view of the separation unit of FIG. 2, when in the operational configuration;

[0075] FIG. 8 shows a plan view of the separation unit of FIG. 2, when in the operational configuration;

DETAILED DESCRIPTION

[0076] FIG. 1 shows an example system for separating synthetic turf infill material in accordance with an embodiment of the present invention. Infill material 105 is fed from a hopper 120 into a tank 101, in which the infill material 105 mixes with water 106. Infill material 105 may be released into the tank at a constant rate, from the hopper 120.

[0077] Optionally, infill material 105 is fed from the hopper 120 via trash screen 124, which separates trash 126 from the infill material 105. The trash screen prevents trash (e.g. debris, which is not sand, rubber or synthetic grass) from passing into the tank 101. Trash is discharged from the screen 124 to a bag or container (not shown) or the like, located adjacent the trash screen. In some embodiments the trash screen prevents particles larger than 5 mm from passing through the screen. Trash 126 is discharged from the top side of the trash screen 124. In other embodiments, different methods of removing debris from the infill material prior to mixing may be employed.

[0078] Optionally, the method takes place at the site of a synthetic turf surface and includes steps of transporting the apparatus to the site and removing the infill material from the synthetic turf surface (not shown).

[0079] Optionally, water 106 is fed into the trash screen 124 from a water recycling unit 116 at the same time as infill material 105 is fed to the trash screen 124, which helps to pass the infill material 105 through the trash screen 124 and separate the infill material 105 from the trash 126. The water 106 and the infill material 105 mix in the tank 101 to form infill slurry 110. In some embodiments the tank 101 is a sump of the trash screen, in other embodiments it may be a separate compartment or part of a hopper. The infill slurry 110 is then pumped from the tank 101 to a hydrocyclone 104. Hydrocyclones are usually used for separating water from heavier particles. In this usage, the synthetic fibres which make up a part of the infill slurry 110 also leave the hydrocyclone in the overflow, with the water. Thus, the hydrocyclone 104 is used to separate synthetic fibres and water (fibre slurry 107) from the infill slurry 110. The synthetic fibre slurry 107 is fed to a fibre screen 130, which separates the synthetic fibres 135 from the water 140. The heavy component which leaves the hydrocyclone in the underflow is a sand and rubber slurry (sand/rubber slurry 111), comprising sand, rubber and water. Water 106 can be injected or otherwise combined with the sand/rubber slurry 111 to ensure the optimum feed consistency of the sand/rubber slurry 111 which is fed to a spiral separator 108. The spiral separator 108 splits sand/rubber slurry 111 into sand slurry 109, rubber slurry 112 and a left-over sand/rubber slurry 128. The sand slurry 109 is fed to a sand screen 150, which separates the sand 155 from the water 141. The rubber slurry 112 is fed to a rubber screen 160 which separates the rubber 165 from the water 142. In the embodiment of FIG. 1 the sand/rubber slurry 128 is recirculated to mix with infill slurry 110 upstream of the hydrocyclone 104. In the same or yet further embodiments, the sand/rubber slurry may, additionally or alternatively be returned into the infill slurry 110 in the tank 101 and/or into the sand/rubber slurry 111. The water 141, 142, 140, which passes through the sand screen 150, rubber screen 160 and synthetic fibre screen 130 is collected below the screens in a hopper or container or sump or the like, and pumped to the separate water recycling unit 116 which comprises a clarifier (not shown) and water storage compartment (not shown), for example a bund or a tank, or water may be fed back into the process at the trash screen and/or into the sand/rubber slurry. The water 141, 142, 140 is treated in the clarifier, and is then stored in the water storage compartment. Water 106 pumped from the water storage compartment of the water recycling unit 116 can be used wherever water is introduced into the process.

[0080] The sand 155, rubber 165, synthetic fibres 135 and trash 126 which are separated in the method may be collected separately by any suitable means, for example in piles, tanks, hoppers, containers, bags or construction sacks. Synthetic fibre 135 and trash 126 may be handled together for disposal. Sand 155 and rubber 165 may be reused in any new synthetic fibre surface laid at the site.

[0081] Optionally, a sand drying unit (not shown) configured to dry the sand 155 separated by the separation unit is also provided.

[0082] Mixing the infill material 105 with water 106, facilitates the use of wet separation processes (separation processes which include water). For an equivalent volume of infill material, wet separation processes can be carried out using more compact and lighter equipment than dry separation processes (where water is not used) such as the one disclosed in WO 2015/059094. Accordingly the system in accordance with the present invention may reduce the overall size of the equipment needed to separate the infill material 105 from one another. Further, the reduction in size may facilitate the separation of infill material on site.

[0083] Additionally or alternatively, use of wet separation processes may lead to improved separation for example sand may appear clear following wet separation in contrast to prior art dry separation processes.

[0084] Additionally or alternatively, by having a water recycling capability, the amount of water required for the separation may be reduced, as, after start-up, the only fresh water that needs to be added to the process is water which replaces that lost through being present with the sand 155, rubber 165, synthetic fibre 135 and debris 126 which exits the system.

[0085] While the system described above uses a spiral separator as a density separator, other types of density separators may be used, for example fluidized bed separators, upflow classifiers and/or separations jigs.

[0086] In the description of FIGS. 2 to 6, reference numerals correspond to those of similar elements in FIG. 1 but incremented by one hundred, for example spiral separator 108 of FIG. 1 corresponds to spiral separator 208.

[0087] FIGS. 2 to 6 show an example separation unit 200 in accordance with an embodiment of the invention. Arranged along one of the long sides of the unit are (in order): A water-collection hopper 269, and a slurry hopper 227. A feed hopper 220 is located at one end of the unit 200, adjacent the slurry hopper 227. The feed hopper 220 is located at the opposite end of the unit to the water-collection hopper 269. A sand screen 257 is located above and toward one end of the water-collection hopper 269. A rubber screen 267 is located above and to the other end of the water-collection hopper 269 and a trash screen 224 is located above the slurry hopper 227. It will be appreciated that in other embodiments the hoppers and screens may be laid out in other, different, configurations or that the hoppers may be replaced with other appropriate containers. Each of the screens 257, 267 and 224 is inclined and vibrated by two motors 209 mounted atop the screen. A bag or sack (not shown) is located adjacent the screen to collect particles retained by the screen

[0088] A dosing unit (not shown) is located within a water recycling unit (not shown) to chemically dose the water to prevent bacterial growth and/or reduce levels of pathogens in the water.

[0089] In FIG. 2, a spiral separator 208 is arranged in a stowed position (suitable for transport or storage) with the longitudinal axis of the spiral separator 208 extending horizontally along the length of the unit above the water-collection hopper 269 and slurry hopper 227. The spiral separator 208 comprises two helical troughs 208a (see FIG. 5) extending along the longitudinal axis of the spiral separator 208. A hydrocyclone and flow distribution chamber, hereafter referred to as hydrocyclone 204, is connected to the distal end of the spiral separator 208 (the end located above the slurry hopper 227 in FIG. 2).

[0090] In FIG. 3, the spiral separator 208 is arranged in an operational position, with the longitudinal axis of the spiral separator 208 extending vertically upwards. In the operative position the spiral separator 208 is located above the water-collection hopper 269.

[0091] The feed-hopper 220 has a conveyor belt/auger 221 which extends between a position adjacent the short edge of the unit and the bottom of the feed hopper 220 to a position above the trash screen 224 and slurry hopper 227. A feed line (not shown) extends from the slurry hopper 227 to the hydrocyclone 204. When shown in the operative position of FIG. 3 the bottom of the hydrocyclone 204 is connected to the top of the spiral separator 208. A first water line (not shown) provides water to the trash screen 224, for example from a separate water recycling unit (not shown). A second water line (not shown) provides water from the water recycling unit to a point between the hydrocyclone 204 and the spiral separator 208. A return line (not shown) connects the hydrocyclone overflow to a water recycling unit, optionally via a fibre screen (not shown). The water recycling unit is contained in a separate unit, and is connected to the separation unit 200 to provide water thereto. Output lines (not shown) connect the bottom of the spiral separator 208 to each of the sand screen 257 and the rubber screen 267.

[0092] The present embodiment comprises two separators: a hydrocyclone 204 and a spiral separator 208. In other embodiments, a different density separator may be used in place of the spiral separator 208, for example a fluidised bed separator, upflow classifier or a hydraulic pulsating separation jig. In the same or yet further embodiments, the hydrocyclone 204 may be absent.

[0093] The arrangement shown in FIGS. 2 to 6 also includes various pumps and piping (not shown for the sake of clarity) which pump/transport the slurries/water in the system.

[0094] The separation unit 200 can fit into the footprint of a standard 20 ft shipping container. In the transport configuration (shown in FIG. 2) the separation unit can fit within the dimensions of a standard 20 ft shipping container (including the height). In the operation configuration (shown in FIG. 3) the spiral separator 208 and hydrocyclone 204 extend above the height of a standard shipping container.

[0095] In use, infill material is removed from the synthetic turf surface and deposited in the feed hopper 220 of the separation unit 200 located at the site of the synthetic turf surface. Debris is removed from the infill material as it passes through the trash screen 224 and the infill material mixes with water to produce infill slurry which is collected in slurry hopper 227. Trash captured by the trash screen 224 is collected separately. The infill slurry from hopper 227 is pumped to the top of the hydrocyclone 204 where it is separated into a fibre slurry and sand/rubber slurry. The sand/rubber slurry passes from the bottom of the hydrocyclone 204 to the top of the spiral separator 208. The fibre slurry passes from the top of the hydrocyclone 204 to the water recycling unit, via a fibre screen (not shown). Optionally, water is mixed with the sand/rubber slurry between the bottom of the hydrocyclone 204 and the top of the spiral separator 208. The sand/rubber slurry passes through the spiral separator which separates the sand/rubber slurry into (i) sand slurry, (ii) rubber slurry and (iii) sand/rubber slurry. The sand slurry flows from the spiral separator 208 to the sand screen 257 where sand is separated from the sand slurry and deposited in a pile or receptacle. Water passes through the sand screen 257 to water-collection hopper 269. The rubber slurry flows from the spiral separator 208 to the rubber screen 267 where rubber is separated from the rubber slurry and deposited in a pile or receptacle. Water passes through the rubber screen 267 to water-collection hopper 269. Thus, the water-collection hopper 269 collects water which has been screened for sand and rubber respectively. Water is pumped from the water-collection hopper 269 to the water recycling unit and/or the water is recirculated back onto the trash screen/into the rubber/sand slurry. Thus, apparatus in accordance with the present example embodiment may effectively separate sand, rubber and fibre from infill material. Additionally or alternatively, apparatus in accordance with the present invention may allow separation to take place on site, thereby reducing transportation costs and/or allowing for reuse of the infill materials in any new synthetic turf surface at that site. Additionally or alternatively, recirculation and recycling of water within the apparatus may reduce the amount of water used during the separation process.

[0096] While a hydrocyclone and spiral separator have been described above it will be appreciated that different forms of density separator may be used, including fluidized bed separators, upflow clarifiers and separation jigs.

[0097] Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein.

[0098] Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.