WO1993009660A1

WO1993009660A1 - Method and apparatus for weeding rows of utility plants

Info

Publication number: WO1993009660A1
Application number: PCT/DK1992/000346
Authority: WO
Inventors: Jan Moerk Hansen
Original assignee: Jan Moerk Hansen
Priority date: 1991-11-21
Filing date: 1992-11-20
Publication date: 1993-05-27
Also published as: DK190191A; AU3081692A; DK190191D0

Abstract

A method and an apparatus for use during weed control in a growthof utility plants and where the control is carried out by using a water jet which under high pressure cuts the stem of the weed on a level with the surface of the ground. The method and the apparatus also comprise means for detecting plants, in such a way that utility plants can be distinguished from weeds, and that the water jet may be interrupted and established when passing a utility plant and a weed, respectively.

Description

METHOD AND APPARATUS FOR WEEDING ROWS OF UTILITY PLANTS. Background of the Invention.

The present invention relates to a method for cutting parts of plants, preferably on weeds, in a row of utility plants.

The invention also relates to an apparatus for use in the method, which apparatus is characterized in that it comprises a supply of liquid, a pump for working up a fluid pressure, a nozzle, one or seve- ral intensifiers, and a jet breaker or a stop valve.

In the agricultural industries weeders have been used for a long time for weeding rows of beets, potatoes, or other geophytes for undesired plants, so-called weeds. In this connection and in the following, inter-row cultivation should be taken to mean that a weeding between the rows is carried out. This is carried out with apparatuses fixed to a hauling machine, normally a tractor, and which is provided with dis- ques, rollers, teeth, or the like. The weeder processes the upper layer of earth between the rows in such a way that the weed is either torn up from the ground with roots or that the part of the weed being above the surface of the ground is cut from the roots. Thus, a tearing up or a cutting of the weed occurs by means of stationary mechanical means.

These weeders are connected with drawbacks in that they may only be used for removal of weeds between the rows in the longitudinal direc¬ tion thereof, but they cannot remove the weeds between the utility plants in the direction transversal to the single rows. It has been attempted to weed mechanically as close to the rows as possible. In practice this is very difficult. Due to the size and the less precise control of known mechanical weeders there is a great risk of affecting the utility plants in the rows which results in a high percentage of loss.

Consequently, chemical weeding methods are used for the removal or extirpation of the weeds which are situated in the rows. Due to the risk of damaging the environment, in particular the ground water, and due to increasing prices of these chemical weed control agents, it is desired to avoid this method of weed control. Accordingly, it is the object of the present invention to provide a method and an apparatus which may be used for weed control. It is the object of the invention to control primarily the weeds which are situ¬ ated in the rows between the utility plants and secondarily the weeds which are situated between the rows without damaging the utility plants. Moreover, it is the object of the invention to provide a method which does not damage the environment in the same way as the chemical agents do.

This is obtained by a method according to the invention, characterized in that a liquid, preferably water, under high pressure is led towards the part of the plant which is situated in the immediate vicinity of the surface of the ground, that the part of the plant is struck by the jet of liquid and is thereby cut in two.

The invention is based on the technique described as water jet cut¬ ting. To a certain extent this technique is used in the industry for cutting plastic sheets, metal, and other materials. The advantage by this rather than the mechanical control of undesi ed vegetation is that the method according to the invention is more careful with utili¬ ty plants which are undesired to control. The cutting is concentrated on a small area which does not affect the surrounding area and accord¬ ingly, there is no risk that the processing in one area gives an unde¬ sired processing in another area, which could involve risk of damaging the utility plants.

The method is primarily intended for controlling undesired vegetation, i.e. weeds, among utility plants. Accordingly, it is necessary that the method gives the possibility of interrupting the water jet when this passes a utility plant, so that the latter is not cut too. This may be complied with if the apparatus is provided with devices which may interrupt or block the water jet when passing the utility plant. For example the device may be a valve which is inserted in the liquid supply pipe, preferably after the pump and before the jet. The device may also be a sheet or the like, which is inserted in front of the jet, and thereby blocking the jet.

In order to make it possible to use the method according to the inven¬ tion for controll ng weeds among utility plants, it is necessary that the method also comprises means for detecting utility plants or for detecting weeds. This detecting may be carried out in several widely different, known ways, e.g. by continuous measuring of the height of the plant either by means of light or sound reflectors, by photo recognition, by some kind of continuous biological or visual plant analysis, or in another way.

The method may be carried out by using one or several nozzles and the control therewith may very precisely be carried out by using a detec- tor which continuously registers whether there is a plant or not. By using the recognition technique the detector may also register the type of plant. This registration is used for controlling the nozzle, so that the jet of liquid may selectively be interrupted when passing a utility plant. Alternatively, the jet of liquid may only be estab- lished by detecting a plant which is to be controlled.

The advantage of the method according to the invention rather than the chemical weed control is that the environment is damaged in a very less degree, and simultaneously avoiding the current expenses for weed control agents for different types of weeds. Some initial expense has to be defrayed for the purchase of an apparatus for use in the method, but this expense makes up for the reduced expenses for the control agents. Moreover, as mentioned, a substantial advantage exists in that the surrounding environment is not damaged by using water jet cut- ting, whereas chemical control may cause pollution of the ground water and destruction of insects and other animals which are important for preserving a natural ecological balance.

The advantages mentioned of the method according to the invention result in a more natural way of controlling undesired vegetation among utility plants, and simultaneously reducing the percentage of loss among the utility plants, caused by the control. Moreover, it is pos¬ sible to add fertilizing subtances, hormones, or other substances to the liquid.

The invention may be used in all kinds of plantations in rows, where undesired vegetation, in a row, of some type is to be removed in order to make room, let in light and air for the utility plants. A further feature of the method according to the invention is that the jet of liquid is directed towards a part of a plant which is situated immediately below the surface of the ground.

The method may be carried out with an apparatus according to another aspect of the invention, and which is characterized in that the weed is detected in the row of utility plants, and that the jet of liquid is established when passing the weed.

The apparatus according to the invention is advantageously provided with one or several means for detecting plants or parts of plants.

According to a preferred embodiment the apparatus is also provided with shielding means which at least shield the detecting means rela- tive to the surroundings so that impurities are prevented from having access to the means.

According to a further preferred embodiment means are provided in con¬ nection with the apparatus for determining the distance between the surface of the ground and the detecting means, respectively the noz¬ zle.

Brief description of the drawing.

The invention will now be further explained with reference to the accompanying drawing, wherein

Fig. 1 shows a schematic view of an apparatus for use in the method, Fig. 2 shows a schematic view of a section through an embodiment for an apparatus for use in connection with the method according to the invention, Fig. 3 shows a possible embodiment for a mean for determining the distance between the surface of the ground and the detecting mean/nozzle, and Fig. 4 shows a further embodiment which substantially corresponds to the embodiment shown in Fig. 3, but seen from the rear.

Fig. 1 shows the individual component elements in a fundamental embo¬ diment for an apparatus for carrying out the method according to the invention. A reservoir 1 supplies a pump 2 with water. The pump for working up a water pressure which if desired is intensified by an intensifier (not shown), and leads the water under pressure to the nozzle 3, through which the water jet 4 is led. The atmospheric pres- sure of the water will be between 400 and 2000. The nozzle 3 is inclined relative to the surface J of the ground at an angle a of between 0° and 45°, preferably of between 0° and 30°.

When the water jet 4 strikes a part of a plant on a plant P, this part of the plant will be cut due to the high pressure of the water jet. The cut part of the plant will preferably be a part close to or just below the surface of the ground, which in most cases will be the stem. However, a cutting of other parts of the plants may also be carried out, said parts being situated above the surface of the ground, such as offshoots, florets, or fruit bodies.

A valve 5 and/or a sheet 6 may be used for interrupting, respectively blocking the water jet 4.

The method, shown by means of the apparatus in the schematic view in Figure 1, may also comprise means for detecting plants and/or parts of the plants in connection with an advantageous use. Either a detecting of the utility plant may be carried out so that the water jet is interrupted when passing the utility plant. Alternatively, the weed may be detected and the water jet is established when passing the weed. The two methods, on which a detecting may be carried out, fulfil the same purposes, viz. to protect the utility plant, however, the methods take starting point in their respective criteria, respectively whether the water jet should be interrupted when detecting a utility plant, or whether the water jet should be established when detecting the weed.

Fig. 2 shows a partial view of a possible embodiment for an apparatus according to the invention comprising a nozzle 3, a detecting mean 7, and a shield 8.

The shield 8 reduces the risk of impurities 9 getting access to the nozzle 3 and the detecting mean 7, respectively. The detecting mean 7 which will be most sensitive to impurities may furthermore be protec- ted by air being blown past the mean 7 through a pipe 10 which sur¬ rounds the mean. This air will blow smaller impurities, e.g. dust par¬ ticles and the like, away from the "field of vision" of the detecting mean. In this way a clean area around the detecting mean is maintained so that operation stop resulting from a smudged mean is avoided.

As the nozzle 3 is not as sensitive to impurities as the detecting mean 7, it is sufficient to shield these means 7 and refrain from shielding the nozzle 3. This may be desirable owing to the availabi- lity of servicing or the like around the nozzle.

As shown, the detecting mean 7 is located naturally in front of the nozzle 3 seen in the direction of travelling, shown with the arrow. If the travelling speed and the distance between the detecting mean and the jet, respectively, is known, it may be determined how long a time after the detecting of the utility plant/weed the water jet should be interrupted/established. Alternatively, it will be possible to locate the detecting mean 7 in a separate part of the apparatus which is not built integral with the nozzle 3. Hereby, the risk of functional errors in the detecting mean is reduced. Such functional errors may frequently be caused by smudging of sensors, optics, and the like, of which the detecting mean 7 is built up.

Fig. 3 shows a principle for how the distance between the surface J of the ground and the detecting mean 7, respectively the nozzle 3, may be determined and kept more or less constant while operating.

A wheel 11 is fixed to a shield 8, in which the detecting mean 7 and the nozzle 3 are located. The whole system 12 consisting of the wheel 11, the shield 8, the detecting mean 7, and the nozzle 3 are suspended to a hauling machine 13. t

The suspension may ensure that the system can be vertically displaced in order to follow the surface of the ground. As shown, the suspension may be carried out by means of lever arms 14, in which the individual bearings 15 form part of hinged bearings, or the suspensions may also be provided with bearings of which the suspension parts are transla- tory displaced relative to each other. In order to ensure that the system 12 follows the surface J of the ground all the time and does not jump when passing the lumps of soil or the like unevenness, the system may be muted with, e.g. a hydraulic cylinder and/or be induced a downward directed force, e.g. in the form of a flat spring.

In Fig. 4 corresponding or identical parts are indicated with the same references as in the above-mentioned Figures. From this, it appears that the nozzle 3 and the detecting mean 7 should be located in the immediate vicinity of the wheel 11, and that the wheel 11 is situated in the immediate vicinity of the row and thereby the plant P. Hereby, a reliable cutting is obtained even though the surface J of the ground is irregular.

Practical tests with an apparatus according to the invention have shown most satisfying results. At the tests plants were cut having a height of approximately 70 mm and a stem diameter of approximately 2 mm. The distance between the nozzle 3 and the plants P was approxi¬ mately 60 mm and the nozzle 3 was located at an angle of approximately 15". A water pressure of 700 bar and a nozzle diameter of 0.5 mm were used. This causes a power consumption of approximately 4 kW and a water consumption of approximately 850 1/hectar at a speed of 5 km/h. With speeds of up to approximately 6 km/h, which is the maximum reali¬ stic speed in connection with inter-row cultivation, it has shown that the remainder of plants which remained standing was under approxi¬ mately 7 per cent. This per cent is acceptable as cutting of certain plants can be prevented by rocks which interrupt the water jet. Fur¬ thermore, the apparatus used was a prototype which was not optimized against locating the wheel 11, the nozzle 3 and the detecting mean 7 in the immediate vicinity of each other, and in the immediate vicinity of a row. Thus, complete consideration to the irregularity of the ground was not fully taken during the tests, and therefore, the water jet has not been adjusted correctly relative to all the plants P.

The illustrated embodiments of apparatuses for use in the method and parts hereto serve only as schematic views for describing how the method may be worked. Furthermore, they serve as an explanation of how practical ways of presenting the problems in connection with the work in growths may be solved in principle, such as establishing or inter- rupting the water jet, detecting plants and parts of the plants, pre¬ venting impurities getting access to sensitive parts of the apparatus and securing of a given relation between the surface of the ground and the system.

Claims

CLAIMS.

1. A method for cutting parts of plants, preferably on weeds, in a row of utility plants, c h a r a c t e r i z e d in that a liquid, prefer- ably water, under high pressure is led towards the part of the plant which is situated in the immediate vicinity of the surface of the ground, that the part of the plant is struck by the jet of liquid and is thereby cut in two.

2. A method according to claim 1, c h a r a c t e r i z e d in that the jet of liquid is directed towards a part of a plant situated imme¬ diately below the surface of the ground.

3. A method according to claim 1 or 2, c h a r a c t e r i z e d in that utility plants are detected among the weeds, and that the jet of liquid is interrupted or blocked when passing the utility plant.

4. A method according to claim 1 or 2, c h a r a c t e r i z e d in that the weed is detected in the row of utility plants, and that the jet of liquid is established when passing the weed.

5. A method according to any one of the preceding claims, c h a r a c - t e r i z e d in that the jet of liquid forms an angle of between 0° and 45°, preferably of between 0° and 30°, with the plane of the sur- face of the ground.

6. A method according to any one of the preceding claims, c h a r a c - t e r i z e d in that the jet of liquid has an atmospheric pressure of between 400 and 2000 (4.05.10⁷ and 20.26.10⁷ N/m²).

7. An apparatus for use in the method according to any one of the pre¬ ceding claims, c h a r a c t e r i z e d in that it comprises a supply of liquid, a pump for working up a fluid pressure, a nozzle, one or several intensifiers, and a jet breaker or a stop valve.

8. An apparatus according to claim 7, c h a r a c t e r i z e d in that it comprises one or several means for detecting plants and/or parts of plants.

9. An apparatus according to claim 7 or 8, c h a r a c t e r i z e d in that shields are provided at least around the detecting means.

10. An apparatus according to claim 7, 8 or 9, c h a r a c t e r - i z e d in that it comprises means for determining the distance between the surface of the ground and the detecting means, respective¬ ly the nozzle.