NZ240568A

NZ240568A - Destruction of weeds using hot water or hot water and steam delivered at high pressure

Info

Publication number: NZ240568A
Application number: NZ24056892A
Authority: NZ
Inventors: Graham Leslie Collins; Richard John Newson
Original assignee: Waipuna Systems Ltd Formerly G; Richard John Newson
Priority date: 1992-05-26
Filing date: 1992-05-26
Publication date: 1994-12-22
Also published as: NZ264258A

Description

<div class="application article clearfix" id="description"> 2405fc? Priority Date(s): Complete Specification Filed: Class: J Publication Date: ...2£££C.199$ P.O. Journal. No: . 2 6 MAY 1992 r v o ~ ..«r o <" P I V" -•' Patents Form No. 5 ■Number—240568 PATENTS ACT 1953 !ii 13, 100-1 COMPLETE SPECIFICATION OXIC VEGETATION CONTROL GRAHAM LESLIE COLLINS, of 135 Pinehaven Road, £Iverstream, New Zealand and RICHARD JOHN NEWSON, of 28 Ferry Road, Days Bay, Wellington, New Zealand, both New Zealand citizens do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - 1 - -2- n ^ $4 The invention comprises a method for killing or controlling weeds. Conventionally weed growth is controlled either by use of herbicide chemicals which are applied to the weeds by spraying or in the form of powder or granules which are sprinkled about the weeds, or alternatively by physically uprooting the weeds. Physically removing the weeds is time consuming and labour intensive. Herbicides can be relatively expensive, and there is increasing resistance to the use of such synthetic chemicals in the environment The present invention provides an alternative method for killing or controlling weeds. In broad terms in a first aspect the invention comprises a method of killing or controlling weeds, comprising applying to the weeds pressurised hot water or hot water and steam at a temperature of substantially 75°C or above, by spraying over the foliage of the weeds, and in which the water is delivered to an outlet therefor at a pressure in excess of 200 p.s.i. Preferably the hot water or hot water and steam is at a temperature of substantially 90°C or above and most preferably at a temperature in the range 90°C to 110°C. The invention will be further described with reference to the accompanying drawings, by way of example only and without intending to be limiting. In the drawings: ■v - ' o, 6419C3AM* 194/BS/IM 13 AUG 1094 -3- *«04«g Figure 1 shows a van mounting apparatus of the invention including both a manual hand held applicator and a towed boom applicator. Figure 2 shows a preferred form of manual hand held applicator of the invention, Figure 3 is a three quarter view from below of the head of the applicator of Figure 2, Figure 4 is a view from immediately below of the head of the applicator of Figure 2, Figure 5 is a view of the towed boom applicator from behind with parts removed, and Figure 6 is a close up view of one outlet of the boom applicator of Figure 5. Figure 1 shows apparatus of the invention mounted to a van, within the van are mounted a water tank 1, a boiler 2 arranged to heat smaller volumes of water supplied by the water tank to the desired temperature, a pump 4, and a pump motor 3. The boiler 2 and pump motor 3 are powered from the battery of the van, or alternatively a separate generator with its own prime mover such as a small petrol motor could also be provided within the van to generate power for the pump motor and boiler. The pump 4 supplies the steam or hot water generated by the boiler 2 to the hand held applicator 5 and the towed boom applicator 6 over flexible hoses 7. Any other water heating or steam generation plant could be employed. For example instead of a boiler, a water heater of the instant flow through type could be used. & N ' q\ •.vl 19 AUG 1994 7 !! C419CSAM.I94/BS/1U -4- The hand held applicator 5 and boom applicator 6 will be described in further detail but each provide an outlet for spraying the steam or hot water over weeds. 75°C has been found to be a practical lower limit for hot water application to weeds to substantially limit regrowth. Temperatures in excess of 90'C and most preferably in the range 90*C to 110"C are preferred. At this temperature the spray from the outlet tends to be a mixture of steam and large droplets of hot water, as opposed to fine mist spray. It is also wet, as opposed to dry superheated steam generated at higher temperatures. This wet steam and hot water droplets mixture has been found most effective in spreading over the foliage and killing it and in reducing the strength of the weeds so that they tend to go limp or collapse to the ground. Also, hot water and wet steam in this temperature range have been found to have an effective root penetration effect so that the hot water/steam tends to penetrate into the ground about the weed roots and kill the root system of the weeds, to further enlarge the time until weed regrowth. Preferably water is delivered whether in the form of hot water or steam or a mixture, at a rate in the range 200 to 1000 litres per hour. Figures 2 to 4 show the preferred form hand held applicator 5. It comprises a shaft 8 and handle 9, and preferably a trigger 10 whereby the operator may turn the spray of steam/hot water on and off. The applicator is connected to the flexible hose 7 which may for example pass down inside the interior of the handle 8 to a nozzle 11 as an outlet at the base of the shaft 8, as shown in Figure 4. The nozzle 11 acts to deliver the hot water and steam as a spray. A shroud 12 suitably shaped as shown is provided V S . ' • •"* "c C419C8AM*l94/B8/na 10 AUG 1994 ^ q 5- ?<0Sff8 about the nozzle 11 to contain the steam about the area beneath the applicator being treated at any instant as the applicator is moved over the ground, and to prevent loe^ dissipation of the steam by wind for example. The shroud may suitably by formed of metal or plastics or any other suitable material. It is preferred but not essential to employ some form of shroud. In the applicator shown in the drawings the front and rear edges of the shroud are enlarged at 12a so that they can move easily over weed foliage. Any other suitable arrangement of shroud could be employed. To maintain the nozzle 11 at a substantially constant spacing above the ground, the applicator comprises wheels 13. The wheels 13 are fixed to the shroud 12 or to some other frame at the base of the shaft 8 which also carries the shroud 12, and are so positioned that the nozzle 11 is positioned at the desired height above the ground. It has been found most desirable that the outlet is positioned at not more than 100 millimeters within the ground for most effective operation. The spacing depends on the volume flow rate and pressure of flow through the nozzle selected and by easy experimentation the optimum or effective height may be found. In the preferred form applicator head with a hot water/steam temperature of about 100°C and a water consumption/flow rate of 100 litres per hour, an outlet spacing from the ground of about 50 millimetres has been found to be most effective. Preferably the spray is delivered at a pressure of between 400 and 1000 psi, for best effect. In use, an operator moves the applicator over the ground by rolling it along on the wheels 13, operating the trigger 10 to spray hot water and steam onto weeds over which •j I- > • j , i' o . « **'' O'; .mcMM.m/Bs/.. i:] AbG 1994 " ■ he rolls the applicator. The wheels 13 ensure that the spray is applied to weeds from the constant height. Alternatively to the wheels 13 a single wheel, or one or more skids could be employed, for example, various other configurations of manually, hand held applicator will be apparent from that described. It is also possible that to enhance penetration to the root system of the weeds, the applicator could include one or more wheels with spikes or tines, for example mounted within the shroud 12, to penetrate the soil surface. Figure 5 shows the preferred form of towed boom applicator 6 from behind. The boom applicator comprises a frame 14 having a draw bar 14a (see Figure 1). The frame 14 forms a boom carrying a spray pipe IS extending along the length of the boom as shown. The spray pipe IS is connected to the hose 7 from the high pressure pump via pipe 16. At either end of the frame/boom are provided ground wheels 17 which maintain a constant spacing between the boom and the ground as the boom passes over the ground. A subsidiary wheel 18 may be provided as shown. A number of outlets 19 are provided from the spray pipe 15, with one preferred arrangement being shown in Figure 6. Each outlet 19 comprises a short length of flexible hose 20 connected to the spray pipe and mounting a nozzle 21 at its lower end. In use hot water or steam passes through the spray pipe 15 down through the short flexible hose 20 and is ejected from the spray nozzle 21 over the ground over which the boom moves. The advantage of the flexible mounting arrangement is that each nozzle -l l N /-'s ,/o V 0 f •% * {■ 2 6419CSAM.894/BS/nt 1 \\ »9 AUG 1994 n.i/, I / -7- 5 6g can deflect when hitting taller weeds or other obstructions. A shroud 22 formed of for example, rubber or plastic flaps or even a rigid shroud, may be provided on either side of the boom to shroud the spray outlets 19 along the boom and contain the spray for maximum effect. Any other suitable shroud arrangement could however be employed. In Figure 5 the shroud is shown partly removed so that the outlets 19 along part of the boom can be seen. One or both sides of the boom may be pivotally mounted. In Figure 5, one side of the boom is pivotally mounted at 23 so that it can pivot upwardly, as that side of the boom passes over a slope, or be pivoted upwardly by cylinder 24 to reduce the width of the boom applicator for towing when not in use, as is known for other types of agricultural equipment comprising a boom for applying herbicides or fertilizers etc. Again, it will be clearly apparent that a boom applicator for applying hot water or steam in accordance with the invention could be otherwise arranged. For example, the boom applicator could be mounted to the front of a tractor instead of being towed. The boom could form part of a purpose built vehicle. For example, a purpose built vehicle could instead of employing a boom have a number of spray outlets on its underside between wheels at four corners of the vehicle with shrouds about the sides of the vehicle towards the ground, to spray weeds as the vehicle is driven over them. Again in the case of a handheld applicator the water supply and water heater could be mounted to a frame to form a back pack unit, powered over a long extension cord from a mains supply or a mobile generator or battery. All such variations and modifications as wiU be apparent , " ' C' ■ \ , * ol\ 6419C3AH.I94/B3/mi " * (J jQCJ^ fr,'i ^0 5® o -8- are intended to be incorporated within the scope of the invention, as defined in the following claims. The following table shows results from one test using the method and apparatus in accordance with the invention, as compared to the commonly employed herbicide glyphosate. Application Conditions with Invention Application temperature: Application rate: (water consumption) Application pressure: Outlet nozzle height from ground: Weed types: 100'C 750 litres per hour 500 psi 50mm Annual and established perennial -9- *4 2? 8 Table Condition Invention (time from appln) Glvphosate (time from appln) Wilting & discolouring Immediate Complete brown off 4 days Visible regrowth 60 days Regrowth cover 50% 85 days Regiowth cover 95% 100 days 10 days 25 days 60 days 85 days 100 days 6419C5AM, 194/BJ/mi -10- 24 0 ; 6 8 With the method and apparatus of the invention, weeds may be controlled without the use of synthetic herbicides and thus in a completely environmentally friendly way. The method and apparatus of the invention have found to be surprisingly effective achieving a kill time in which weeds are brown and clearly dead after application in the range of a few days, as opposed to one to three weeks for commonly employed herbicides. Also, the cost of synthetic herbicides is avoided. </div>

Claims

<div class="application article clearfix printTableText" id="claims"> n & *;-11-;24;What We Claim Ts:;1. A method of killing or controlling weeds, comprising applying to the weeds pressurised hot water or hot water and steam at a temperature of substantially 7S°C or above, by spraying over the foliage of the weeds, and in which the water is delivered to an outlet therefor at a pressure in excess of 200 p.s.i.;2. A method as claimed in claim 1, wherein the spray is delivered at a pressure in the range 400 to 1000 p.s.i.;3. A method as claimed in claim 1 or 2 comprising applying to the weeds hot water or hot water and steam at a temperature of substantially 90°C or above.;4. A method as claimed in claim 3, comprising applying to the weeds hot water or hot water and steam at a temperature in the range 90°C to 110°C.;5. A method as claimed in any one of the preceding claims, wherein the spray comprises a mixture of hot water droplets and wet steam.;6. A method as claimed in any one of the preceding claims, wherein the hot water or hot water and steam is applied through the outlet from which the hot water or hot water and steam is sprayed, positioned not more than 100 millimetres from the ground.;•: . ■ • C;* s' 'V 6419CSAM.194/BS/raa •„ TO AUU 1994 -12- 7. A method as claimed in any one of the preceding claims, wherein the temperature is sufficiently high to kill the weeds. 8. A method as claimed in any one of the preceding claims, wherein the hot water or hot water and steam penetrates to kill the root system of the weeds. 9. A method of killing or controlling weeds, substantially as described herein and as shown in the accompanying drawings. JAMES W PIPER & CO Attorneys for: Waipuna Systems Limited 64X9CSAM. 194/Bfl/ftf </div>