APPARATUS AND METHOD FOR CONTROLLING WEED GROWING ON A GROUND SURFACE

Abstract

An apparatus for controlling weed growing on a ground surface includes a liquid supply system configured to supply hot liquid, and dispensing means are operatively connected to the liquid supply system. The dispensing means are configured to dispense hot liquid to the weed. The liquid supply system includes at least one buffer tank that is configured to store and supply hot liquid, a liquid supply container is connected to the at least one buffer tank, and a direct supply line extends between the supply container and the at least one buffer tank. The direct supply line is configured to supply unheated liquid from the supply container directly to the at least one buffer tank and a hot liquid supply line including heating means for heating liquid supplied from the supply container to the at least one buffer tank. A method for controlling weed growth.

Claims

1. An apparatus for controlling a weed (W) growing on a ground surface (S), the apparatus comprising: a liquid supply system configured to supply hot liquid; and dispensing means operatively connected to the liquid supply system, wherein the dispensing means are configured to dispense the hot liquid to the weed on the ground surface (S); wherein the liquid supply system comprises: at least one buffer tank that is configured to store and supply the hot liquid; a liquid supply container that is connected to the at least one buffer tank; a direct supply line extending between the supply container and the at least one buffer tank, the direct supply line being configured to supply liquid from the supply container directly to the at least one buffer tank; and a hot liquid supply line that includes heating means for heating the liquid supplied from the supply container to the at least one buffer tank.

2. The apparatus according to claim 1, further comprising a drain line that extends between the at least one buffer tank and the supply container and that is configured to discharge liquid from the at least one buffer tank to the supply container.

3. The apparatus according to claim 1, wherein the direct supply line comprises one or more mixing devices.

4. The apparatus according to claim 3, wherein the direct supply line comprises at least one signal-generating temperature sensor, wherein the mixing devices are configured to be controlled based on the signals generated by the at least one temperature sensor.

5. The apparatus according to claim 3, comprising a number of additional signal-generating temperature sensors.

6. The apparatus according to claim 1, wherein one or more of the hot liquid supply line, the direct supply line and/or the drain line are provided with a pump.

7. The apparatus according to claim 2, wherein the liquid supply system is configured to, during use of the apparatus, replenish the at least one buffer tank with hot liquid from the heating means, and to drain any excess liquid from the buffer via the drain line to the supply container in order to avoid overfilling of the buffer tank.

8. The apparatus according to claim 1, wherein the supply container and/or the at least one buffer tank are insulated.

9. The apparatus according to claim 2, wherein the hot liquid supply line is connected to the direct supply line downstream of the one or more mixing devices.

10. The apparatus according to claim 1, wherein the heating means comprise a number of burners and/or a number of electrical heating elements.

11. The apparatus according to claim 1, further comprising a frame that is configured to support the apparatus over the ground surface (S).

12. The apparatus according to claim 1, further comprising a control unit that is configured to control one or more of: hot liquid distribution from the buffer tank to the dispensing means; liquid supply from the supply container to the at least one buffer tank via the direct and/or hot liquid supply line.

13. The apparatus according to claim 1, further comprising search and/or detection means that are configured to search for and/or detect the weed (W), wherein the hot liquid is only dispensed onto or in the direct vicinity of detected weed (W) plants.

14. The apparatus according to claim 1, wherein the at least one buffer tank is a pressure tank that, during use, is pressurized, wherein the pressure is in the range of 0.2-4 bar.

15. A method for controlling weed (W) growing on a ground surface, comprising: providing an apparatus according to claim 1; during operation supplying hot liquid, via the hot liquid supply line, to the at least one buffer tank; dispensing hot liquid, via the dispensing means, to weed on the ground surface that is to be controlled.

16. The method according to claim 15, further comprising the step of via the drain line draining excess liquid from the at least one buffer tank to the supply container to avoid overfilling of the buffer tank.

17. A liquid supply system that is configured to be used in an apparatus for controlling weeds (W) growing on a ground surface (S), the liquid supply system comprising: at least one buffer tank that is configured to store and supply hot liquid; a liquid supply container that is connected to the at least one buffer tank; a direct supply line extending between the supply container and the at least one buffer tank, the direct supply line being configured to supply liquid from the supply container directly to the at least one buffer tank; and a hot liquid supply line that includes heating means for heating the liquid supplied from the supply container to the at least one buffer tank.

18. The apparatus according to claim 3, wherein the one or more mixing devices comprise mixing valves.

19. The apparatus according to claim 3, wherein the one or more mixing devices comprise one or more temperature controlled mixing valves.

20. The apparatus according to claim 1, wherein the at one least buffer tank is a pressure tank that, during use, is pressurized, wherein the pressure is in the range of 1-3 bar.

Description

[0077] Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:

[0078] FIG. 1 shows a schematic example of an apparatus according to the invention;

[0079] FIG. 2 shows a schematic view of an example of a part of the apparatus comprising the control unit; and

[0080] FIG. 3 shows a schematic side view of an example of a vehicle carrying an apparatus according to the invention.

[0081] In an example of apparatus 2 (see FIG. 1), apparatus 2 comprises supply container 4 in which a large quantity of liquid, in this example water, can be stored. Essentially, supply container 4 in this example is water tank 4. Supply container 4 in this example is insulated supply container 4 having insulation layer 6. Due to insulation layer 6 supply container 4 can not only be provided with cold water, yet also with (pre-)heated water having a higher temperature (without incurring heat loss to the environment 8). Supply container 4 further comprises temperature sensor 14, which is used to generate temperature information about the stored water in supply container 4.

[0082] Apparatus 2 further comprises buffer tank 10, which is provided with insulation layer 12. Buffer tank 10 in this example is configured to store hot water, which means water with a temperature in excess of 70? C. Preferably, the amount of insulation in insulation layer 12 is sufficient for storing water at temperatures in the range of 95? C.-110? C., more preferably around 105? C. Providing such elevated temperatures in the buffer tank is required, because the liquid cools during transport to the dispensing means. It has been found that providing the mentioned temperature range in the buffer tank allows the liquid dispensed to the ground surface to be at a (desired) temperature of 99? C. or 100? C.

[0083] Direct supply line 16 extends between supply container 4 and buffer tank 10 and forms a direct connection that allows a flow of water from supply container 4 to buffer tank 10. Direct supply line 16 is in this example provided with supply pump 17, which is used to pump liquid to buffer tank 10. This is especially relevant if buffer tank 10 is a pressure vessel, because pump 17 is than used to provide the required pressure to transport liquid to buffer tank 10. For example, if buffer tank 10 is provided under a pressure of 2 bar, the pressure provided by pump 17 is around 3.5 bar. Direct supply line 16 is in this example provided with a number of mixing valves 18, which are connected to control unit 22 and temperature sensor or sensors 20 and/or temperature sensor 32 (see FIG. 2). This allows water to be provided to buffer tank 10. In this particular case, hot liquid supply line 24 emanates in direct supply line 16 before the joined flow enters buffer tank 10 at inlet 10a. It is of course possible to provide separate connections of direct supply line 16 and hot liquid supply line 24 to buffer tank 10. In this specific example, direct supply line 16 is provided with splitter 26, which is positioned upstream of mixing valves 18. As said, splitter 26 is connected to mixing valves 18 on the one side and to return line 28, which is emanates in hot liquid supply line 24 upstream of heating means 30. This allows at least part of the liquid from the direct supply line to be rerouted to the hot liquid supply line, and more specifically to heating means 30 positioned therein. In this example, return line 28 comprises pump 28a. Temperature sensor 32 is provided near or at splitter 26 to provide temperature data on the flow in direct supply line 16.

[0084] Hot liquid supply line 24 extends from supply container 4 to heating means 30 and onwards from heating means 30 to buffer tank 10. Hot liquid supply line 24 in this example comprises pump 34 to propel the water through supply line 24 towards buffer tank 10. It is noted however that pump 34 in some cases is not necessary. This is for example the case if supply container 4 is filled with warm or hot water from an external source. Heating means 30 in this example is provided as burner 30, yet may also be provided as electrical heater 30. Heating means 30 is provided with temperature sensor 36, which is configured to generate temperature information about the water flowing through heating means 30.

[0085] Apparatus 2 further comprises drain line 38, which connects an outlet of buffer tank 10 to an inlet of supply container 4. In this example, drain line 38 is provided with drain valve 40 or buffer draw valve 40 that allows hot water to be discharged from buffer tank 10 to supply container 4 in case the water level in buffer tank 10 exceeds a predetermined threshold. Drain line 38 therewith allows a supply of hot water through hot liquid supply line 24 without overfilling buffer tank 10. Due to drain line 38, hot water can be provided to supply container 4, which increases the temperature of the water stored in supply container 4. As a result, the energy required to heat the water from supply container 4 to buffer tank 10 (via hot liquid supply line 24) is reduced. Essentially, the heat in the hot water is largely conserved by the recirculation to supply container 4.

[0086] Apparatus 2 is further provided with (schematically shown) dispensing means 44 that are connected to an outlet of buffer tank 10 and to an inlet of buffer tank 10, which allow liquid to be circulated through dispensing means 44 even when no liquid is dispensed (see FIG. 1). Dispensing means 44 may for example comprise at least one ring-shaped line having dispensing openings. In another example, two ring-shaped lines may be provided. Each dispensing opening in may be provided with an associated discharge valve, which can be opened and closed to regulate the outflow of hot water. However, other configurations of dispensing means 44 may be possible as well.

[0087] Apparatus 2 in this example further also comprises (schematically shown) search and/or detection means 52 that are configured to search for and/or detect weed(s) W (see FIG. 2). This allows the hot water from dispensing openings 48 to be only discharged onto or in the direct vicinity of detected weed W plants. This reduces the amount of hot water required to remove weed W, since it is only applied locally.

[0088] In use of apparatus 2, a flow of water F from supply container 4 is provided to hot liquid supply line 24 to heating means 30 in which it is heated to become hot water. The hot water flow from heating means 30 is provided to buffer tank 10. Simultaneously, temperature sensor 20 measures the temperature of the flow of water towards inlet 10a of buffer tank 10. The signals of sensor or sensors 20 are processed by control unit 22, which regulates mixing valves 18 based on the temperature data provided by sensors 20 and, in this example, a predetermined temperature set-point. This means that water U from direct supply line 16 is selectively mixed with water flow F from hot liquid supply line 24 to provide hot water with a desired temperature. In this case, water flow F is mixed into water flow U. If the supply of hot water raises water level L in buffer tank 10 above a predetermined threshold L.sub.max, drain valve 40 in drain line 38 is opened and hot water is discharged to supply container 4. This means that heating means 30 is operated to heat the relatively low volume, low pressure flow F of water in hot liquid supply line 24, allowing heating means 30 to operate at or near optimum capacity. It also allows heating means 30 to have a relatively low heat generating capacity. The regulation/control of the temperature in buffer tank 10 is executed by control unit 22 by regulating the flow U of water from direct supply line 16 to buffer tank 10 and/or the flow F from hot liquid supply line 24. This provides a significant reduction in energy use of apparatus 2.

[0089] Apparatus 2 preferably comprises control unit 22 that is configured to control one or more aspects of apparatus 2. In this example (see FIGS. 1 and 2), control unit 22 is configured to receive temperature signals from temperature sensors 14, 20, 32 and 36, which provide control input for control unit 22. Temperature information provided by the signals from temperature sensor 32 and/or 20 are for example used by control unit 22 to control mixing valves 18 to regulate the amount and/or temperature of the hot water in buffer tank 10. The regulation of the amount of hot water in buffer tank 10 may further also be regulated by control unit 22 by using drain valve 40. The dispensing means 44 are in this example mainly regulated by control unit 22 using input from search and/or detection means 52.

[0090] In a schematic side view (see FIG. 3), an example of apparatus 102 is provided on self-propelled vehicle 100. Vehicle 100 comprises driver cabin 156 being positioned on vehicle frame 158. In this example, vehicle 100 further comprises wheels 160 and an engine (not shown) that are connected to frame 158 to move vehicle 100 and apparatus 102 around. A front end of vehicle 100 is provided with dispensing means 144 and buffer tank 110 of apparatus 102, whereas supply container 104 of apparatus 102 is positioned on the back of vehicle 100 and is in this example enclosed in a separate housing 162 (and therefor only partially visible in FIG. 3). Housing 162 is optional and is not required. Buffer tank 110 is connected to supply container 104 by means of conduit 164. Dispensing means 144 are connected to buffer tank 110 and are used for supplying hot water to and returning (unused) hot water from and to buffer tank 110. It is noted that in the shown example (see FIG. 3), dispensing means 144 and buffer tank 110 are positioned on a separate frame 166 that is (preferably removably) connected to frame 158.

[0091] The present invention is by no means limited to the above described preferred embodiments thereof. The rights sought are defined by the following claims within the scope of which many modifications can be envisaged.