DEVICE AND METHOD FOR KILLING WEEDS BY APPLICATION OF A HIGH TEMPERATURE FLUID

Abstract

A device for killing weeds by application of a high temperature fluid to the weeds includes an elongated applicator chamber having a plurality of fluid discharge openings and an elongated distributing member arranged in the applicator chamber. The distributing member includes at least one fluid inlet and a plurality of distribution openings in fluid communication with the applicator chamber. A method for killing weeds by application of a high temperature fluid to the weeds includes: supplying the high temperature fluid to at least one inlet of an elongated distributing member; distributing the high temperature fluid in a longitudinal direction of the distributing member; transferring the high temperature fluid to an elongated applicator chamber through a plurality of distribution openings; and applying the high temperature fluid to the weeds through a plurality of fluid discharge openings.

Claims

1. A device for killing weeds by application of a high temperature fluid to the weeds, comprising: an elongated applicator chamber having a plurality of fluid discharge openings; and an elongated distributing member arranged in the applicator chamber, wherein the distributing member comprises at least one fluid inlet and a plurality of distribution openings in fluid communication with the applicator chamber.

2. The weed killing device according to claim 1, wherein the distribution openings are spaced apart in a longitudinal direction of the distributing member.

3. The weed killing device according to claim 2, wherein the distribution openings are substantially evenly spaced apart in the longitudinal direction.

4. The weed killing device according to claim 1, wherein the distribution openings are substantially aligned.

5. The weed killing device according to claim 1, wherein the fluid discharge openings define a first fluid flow direction and the distribution openings define a second fluid flow direction which is oriented at an angle with respect to the first fluid flow direction.

6. The weed killing device according to claim 5, wherein the second fluid flow direction is substantially opposite to the first fluid flow direction.

7. The weed killing device according to claim 1, wherein the fluid discharge openings are spaced apart in a longitudinal direction of the applicator chamber.

8. The weed killing device according to claim 7, wherein the fluid discharge openings are substantially evenly spaced apart in the longitudinal direction.

9. The weed killing device according to claim 1, wherein the fluid discharge openings are substantially aligned.

10. The weed killing device according to claim 1, wherein the distribution openings are spaced apart in a longitudinal direction of the distributing member; wherein the fluid discharge openings are spaced apart in a longitudinal direction of the applicator chamber; and wherein the longitudinal direction of the distributing member and the longitudinal direction of the applicator chamber are substantially parallel.

11. The weed killing device according to claim 10, wherein the distributing member extends over substantially the entire length of the applicator chamber.

12. The weed killing device according to claim 10, wherein the distribution openings are spaced further apart than the fluid discharge openings.

13. The weed killing device according to claim 10, wherein the distribution openings and the fluid discharge openings have substantially the same dimensions.

14. The weed killing device according to claim 1, wherein the distributing member has an outer surface which is spaced apart from an inner wall of the applicator chamber.

15. The weed killing device according to claim 1, wherein the distributing member has a smooth cross-sectional shape.

16. The weed killing device according to claim 15, wherein the distributing member is tubular and has a substantially circular cross-section.

17. A method for killing weeds by application of a high temperature fluid to the weeds, comprising: supplying the high temperature fluid to at least one inlet of an elongated distributing member; distributing the high temperature fluid in a longitudinal direction of the distributing member; transferring the high temperature fluid to an elongated applicator chamber through a plurality of distribution openings; and applying the high temperature fluid to the weeds through a plurality of fluid discharge openings.

18. The method according to claim 17, wherein a flow direction of the high temperature fluid is changed between said transferring the high temperature fluid and said applying the high temperature fluid.

19. The method according to claim 18, wherein the flow direction of the high temperature fluid is substantially reversed between said transferring the high temperature fluid and said applying the high temperature fluid.

20. The method according to claim 18, wherein between said transferring and said applying, the high temperature fluid exiting the distribution openings flows around the distributing member to the fluid discharge openings.

21. The method according to claim 18, wherein the flow direction of the high temperature fluid is oriented at an angle with respect to the longitudinal direction of the distributing member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention will now be illustrated by reference to the enclosed drawings, in which:

[0028] FIG. 1 is a general lay out of a system for killing weeds by application of high temperature fluid;

[0029] FIG. 2 is a perspective view of a handheld device for killing weeds in accordance with an embodiment of the invention;

[0030] FIG. 3 is a longitudinal sectional view of the applicator chamber and distributing member of the weed killing device along the line in FIG. 2;

[0031] FIG. 4 is a cross-sectional view of the applicator chamber and distributing member along the line IV-IV in FIG. 3;

[0032] FIG. 5 is a perspective view of the fluid flow around the distributing member, in which the applicator chamber is shown in phantom lines; and

[0033] FIG. 6 is a flow diagram showing the main steps of a method for killing weeds by application of high temperature fluid in accordance with an embodiment of the invention.

[0034] It should be noted that the figures in the drawings are not to scale and that some features may be out of proportion.

DETAILED DESCRIPTION

[0035] A system 1 for killing weeds W by application of a high temperature fluid F comprises a source 2 of high temperature fluid, a weed killing device 3 and a conduit 4 connecting the weed killing device 3 with the source 2 (FIG. 1). In the present embodiment the source 2 comprises a first reservoir or buffer 5 which is filled with high temperature fluid, e.g. hot water, as well as a second reservoir or buffer 6 which is filled with cold fluid, e.g. cold water. A line 7 connects the second buffer 6 with a heater 8, which may be any suitable type of heater, such as a burner, an electric heater, a microwave or an infrared radiator. Instead of a second buffer 6, the heater 7 may also be connected with a water mains 16 (indicated in phantom lines). A line 9 connects the heater 8 to a switching valve 10. The first buffer 5 is connected with the switching valve 10 by a line 11. The switching valve 10 connects either the first buffer 5 or the second buffer 6 and heater 8 with the conduit 4. The source 2 of high temperature fluid may be carried by a user of the system 1, or it may be mounted on e.g. a vehicle, which may be a towed vehicle or a self-propelled vehicle.

[0036] The source 2 supplies fluid to the weed killing device 3 at a temperature which may be in the range of 80-120 C. In particular, the fluid is usually supplied at a temperature between 98 C. and 110 C. In actual practice the supply temperature is in the narrow range of 98-102 C. The weed killing device 3 is arranged to apply the high temperature fluid to the weeds at relatively low pressures of e.g. 0-2 bar over ambient pressure, i.e. substantially pressureless. The source 2 may be configured to supply the high temperature liquid at a flow rate between 3 and 40 l/min, depending on the dimensions of the system and its intended use. In actual practice the flow rate requirements may be in the range of 5 to 20 l/min.

[0037] In the present embodiment the conduit 4 comprises a flexible part or hose 12 and a rigid part or tube 13 (FIG. 2). This tube 13 forms part of a shaft which connects a handle 14 with the weed killing device 3. The handle 14 may include a movable control member 15, like e.g. a trigger.

[0038] The weed killing device 3 comprises an elongated applicator chamber 17 which is closed on all sides but has a plurality of fluid discharge openings 18 arranged in its bottom wall 19 (FIG. 3). An elongated distributing member 20 is arranged within the applicator chamber 17. The distributing member 20, which is also closed on all sides, has an inlet 21 which extends through an opening 22 in a top wall 23 of the applicator chamber 17 and which is connected to the tube 13. The connection may be established in any desired way, e.g. by screwing a threaded connector over the inlet 21 or by means of a bayonet connector. A restriction (not shown) may be arranged either in the tube 13 or in the inlet 21. An outer end of the inlet 21 may be bent to allow a more ergonomic tilted position of the shaft and tube 13. The distributing member 20 further has a plurality of distribution openings 24 which are aligned in a row that extends in a longitudinal direction Ldm of the distributing member. The distribution openings 24 are spaced apart in the longitudinal direction Ldm. In the illustrated embodiment the distribution openings 24 are equidistant and have a spacing Sdm.

[0039] In the illustrated embodiment the fluid discharge openings 18 in the bottom wall 19 of the applicator chamber 17 are also aligned in a longitudinal direction Lac of the applicator chamberwhich is shown to be parallel to the longitudinal direction Ldm of the distributing member 20. The fluid discharge openings 18 are spaced apart in the longitudinal direction Lac. In the illustrated embodiment the fluid discharge openings 18 are equidistant and have a spacing Sac. In this embodiment the spacing Sac of the fluid discharge openings 18 is smaller than the spacing Sdm of the distribution openings 24. Since the distributing member 20 is shown to extend from the inlet 21 to opposite sidewalls 25, i.e. over substantially the entire length of the applicator chamber 17, this means that the number of fluid discharge openings 18 is greater than the number of distribution openings 24. In this embodiment each fluid discharge opening 18 has a diameter Dac that is smaller than a diameter Ddm of each of the distribution openings 24, which compensates for the greater number of fluid discharge openings 18. The total surface area of the two sets of openings 17, 24 may be substantially equal, so that pressure fluctuations are prevented.

[0040] The spacing Sdm of the distributing openings 24 may vary between approximately 25 mm and 80 mm, depending on the intended use of the weed killing device 3. More in particular, the spacing Sdm may be between 40 mm and 50 mm. The spacing Sac of the fluid discharge openings 17 may be between 5 mm and 20 mm, more in particular between 5 mm and 15 mm Again depending on the intended use, the distribution openings 24 may have a diameter Ddm of between 1.0 mm and 3.0 mm, more in particular between 1.5 mm and 2.5 mm. In the illustrated embodiment the diameter Ddm of the distribution openings 24 is approximately 2 mm. The fluid discharge openings 18 may have a diameter Dac of between 1.0 mm and 2.5 mm, more in particular between 1.5 mm and 2.0 mm. The diameters Ddm and Dac on one hand and the spacings Sdm and Sac on the other are selected such that specific pressures may be established inside the distributing member 20 and inside the applicator chamber 17. While the fluid may exit from the applicator chamber 17 almost pressureless, the pressure in the distributing member may be somewhat higher, in the range of 1-5 bar.

[0041] The number of distribution openings 24 and fluid discharge openings 18 obviously depends on the length of the distributing member 20 and the length of the applicator chamber 17, respectively. Depending on the intended use of the weed killing device 3 this length may vary between 20 cm and 100 cm or more. The cross-sectional dimensions of the applicator chamber 17 and distributing member 20 can be selected as a function of the fluid flow rate for which the device 3 is designed. In the illustrated embodiment the applicator chamber 17 has a square cross-section of 2525 mm, while the distributing member 20 has a diameter of 15 mm, but these dimensions may vary within broad ranges.

[0042] Whereas the fluid discharge openings 18 are arranged in the bottom wall 19 of the applicator chamber 17, the distributing openings 24 are not arranged in the bottom of the distributing member 20, but rather near the top of that member. Consequently, fluid flowing into the distributing member 20 from the inlet 21 is not just deflected over a substantially right angle to spread out in the longitudinal direction Ldm, but is further deflected upwardly to reach the distributing openings 24. In this way two opposite swirling fluid flows are established in the distributing member 20, each directed at an end 26 thereof. These ends 26 are both closed off, so that the fluid can only exit the distributing member 20 through the distribution openings 24.

[0043] After leaving the distribution openings 24, the fluid flows into the applicator chamber 17. In this embodiment the applicator chamber 17 has a substantially square cross-sectional shape, and the distribution openings 24 are substantially directed at a corner 27 between the top wall 23 and a front wall 28 of the applicator chamber 17 (FIG. 4). As a result, a fluid flow direction which is defined by the distribution openings is mainly upward, and is almost opposite to a fluid flow direction which is defined by the fluid discharge openings 18 in the bottom wall 19 of the applicator chamber 17. The distributing member 20 is arranged in the applicator chamber 17 in such a way that its outer surface is spaced apart from all inner walls of the chamber. To this end a spacer 30 is arranged around a part of the inlet 21 inside the chamber. The distributing member 20 is fixed in the applicator chamber 17 by means of a nut 31 which is screwed onto a threaded outer segment of the inlet 21. Thus, the fluid flowing out of the distribution openings 24 can flow around the distributing member 20 in the direction of the fluid discharge openings 18. In order to facilitate such fluid flow, the distributing member 20 has a smooth cross-sectional shape, in this embodiment a circular shape, so that the distributing member 20 is a tube.

[0044] Since the spacing Sdm of the distribution openings 24 differs from that of the fluid discharge openings 18, the fluid flow will not be parallel to the inlet 21, but will necessarily have a component in the longitudinal direction Ldm, Lac. Therefore, the fluid flow in the applicator chamber 17 will spiral around the distributing member 20 in opposite directions (FIG. 5), thus leading to intimate mixing of all parts of the fluid, so that a uniform fluid temperate and fluid pressure are established throughout the applicator chamber 17. This in turn leads to a uniform fluid flow out of all fluid discharge openings 18, so that all the weeds W will be subject to treatment with fluid at the same temperature and the same pressure, and in the same stateliquid or vapour. In this way the weeds W can be effectively and efficiently killed.

[0045] The weed killing device 3 described above allows the user to perform a method for killing weeds by application of a high temperature fluid to the weeds, which method 100 comprises the following steps. In a first step 101 (FIG. 6) the high temperature fluid F is supplied to at the inlet 21 of the elongated distributing member 20. In a subsequent step 102 the high temperature fluid is distributed in the longitudinal direction Ldm of the distributing member 20. The next step 103 of the method involves transferring the high temperature fluid to the elongated applicator chamber 17 through the plurality of distribution openings 24. And in the final step 105 the high temperature fluid is applied to the weeds W through the plurality of fluid discharge openings 18. As shown in FIGS. 4 and 5, the method may include an additional step 104 between the transferring step 103 and the applying step 105. This additional step 104 involves changing the flow direction of the fluid between the moment the flow exits the distributing openings 24 and the moment the flow enters the fluid discharge openings 18. In fact, in step 104 the flow direction is almost reversed from upwardly directed under an angle of some 45 to directed straight down onto the weeds W.

[0046] Although the invention has been illustrated by reference to an exemplary embodiment thereof, it will be clear that it is not limited to this embodiment.

[0047] In fact, the weed killing device 3, which has been described as being handheld, could equally well be mounted on a frame that forms part of a vehicle or is towed thereby. To alleviate the workload of a user, the handheld device could be provided with support wheels mounted on the applicator chamber. The advantages of a more uniform distribution of the high temperature fluid are not limited to handheld devices. In fact, these advantages are actually more pronounced when the length of the applicator chamberand thus the distance from the inlet to the outermost fluid discharge openingsbecomes greater.

[0048] The number of distribution openings and the number of fluid discharge openings can be varied, as can be their spacing and their dimensions. In general, lower fluid flow rates require smaller openings and/or smaller numbers of openings in order to maintain sufficiently high pressures within the distributing member and the applicator chamber to ensure a uniform distribution. The shape of the various openings can also be adapted. And although both the distribution openings and the fluid discharge openings are shown to be equidistant in the illustrated embodiment, their spacing could also vary as a function of their distance to the inlet, so as to compensate for pressure losses as a result of drag. The same effect could be achieved by varying the size of the openings.

[0049] The position of the distribution openings in the distributing member could be varied as well. In the shown embodiment they are oriented towards an upper corner of the applicator chamber, but they could also be oriented vertically upward. The orientation should be selected such that the fluid exiting the distribution openings is always forced to flow around the distributing member to reach the fluid discharge openings.

[0050] Although the inlet has been shown to be connected to the distribution member at a central location and perpendicular to the longitudinal direction, it could also be arranged in-line with the distributing member and connected to one of the opposite ends of that member.

[0051] And finally, although in the illustrated embodiment a tubular distributing member is shown to be arranged in a square beam applicator chamber, these two parts could have identical or at least similar cross-sectional shapes. This may be useful for ease of manufacturing. The dispensing member could be a square beam as well, or the applicator chamber could be a tube. Other shapes are conceivable as well.

[0052] The scope of the invention is defined solely by the following claims.