WO2003011022A1

WO2003011022A1 - System for spraying pesticide or similar fluids on agricultural fields, sprraying nozzle, method of spraying and use thereof

Info

Publication number: WO2003011022A1
Application number: PCT/DK2001/000524
Authority: WO
Inventors: Bo Leander Gylling
Original assignee: Bo Leander Gylling
Priority date: 2001-08-01
Filing date: 2001-08-01
Publication date: 2003-02-13

Abstract

The invention relates to a system for spraying pesticide on agricultural fields. The system comprises at least one container () containing pesticide, at least one set () of spraying nozzles () said at least one set comprising at least two spraying nozzles () and said at least one set having connections so said at least one container. The system further comprises control means controlling the flow of pesticide through said connections to said at least one set of spraying nozzles, and the spraying parts () of said at least two spraying nozzles () being angled towards each other and spraying simultaneously. The invention also relates to a set of nozzles, a method of spraying pesticide on agricultural fields and use of a set of nozzles.

Description

SYSTEM FOR SPRAYING PESTICIDE OR SIMILAR FLUIDS ON AGRICULTURAL FIELDS, SPRAYING NOZZLE, METHOD OF SPRAYING AND USE THEREOF

Background of the invention

The present invention relates to a system for spraying pesticide or similar fluids on agricultural fields, a spraying nozzle, a method of spraying and use thereof.

Known systems within the area often comprise a number of nozzles positioned on a boom and spaced apart at a distance of e.g. 50 cm (an example is shown in fig. 1). The boom with the tank containing pesticide may be on wheels and is usually moved over a field by a tractor while the nozzles spray pesticide on the agricultural products being produced.

A variety of different nozzle types may be used. However, the basic functionality of the various nozzle types is the same (an example is shown in fig. 2). The nozzle is connected with a reservoir of fluid that is pressed through an opening in the nozzle to the exterior by a force F. When the fluid leaves the opening, it first expands into a thin film which subsequently turns into separate drops in a wide jet. The shape of the jet is usually triangular with the spraying nozzle determining the angle of the triangle. Further, the depth of the jet can be quite narrow or more round depending of the nozzle type with the angle and depth of the jet having significant impact on the resulting spraying characteristics.

The variation in drop size will be quite large from droplets with a diameter less than 100 μm to drops in excess of 350 μm. The different drop sizes are a serious problem since the smallest droplets are carried away by the wind or vaporise before they hit the agricultural products or the field. Meanwhile, the largest drops in the jet are spread so far apart that the risk of missing several of the insects is excessive. Further, the largest drops may slide off the agricultural products being sprayed. The normal solution to these problems is to overdose pesticide to ensure a certain coverage. A further problem is the fact that the nozzle size, the force F and the speed of the boom determine the amount of pesticide being sprayed. Neither of these factors is easily changed during use and changes e.g. in the weather or field conditions all require that spraying is stopped before any modifications can be made.

In a known system, the nozzle is replaced by a roundel containing three nozzles with different nozzle size. During a stop, the roundel may be turned and another nozzle used. Hereby, it is possible to change the amount of pesticide being sprayed which is not possible during use since this will result in unsprayed areas.

In total, the known systems are inefficient in use and less precise in deliverance of the substance which leads to increased pollution of the surroundings.

The purpose of the invention is to create a spraying system that sprays the pesticide on the agricultural products in an optimal way and hereby decreases the total amount of pesticide used.

Especially, it is an object of the invention to create a spraying system that sprays a jet of drops with only limited variation in size. Especially, drops of medium size within a range of 150 to 250 μm are preferable since adherence to the agricultural products is higher.

Further, it is an object of the invention to create a spraying system that allows changes in the amount of pesticide being sprayed during spraying.

The invention

The objects of the invention are achieved by the spraying parts of said at least two spraying nozzles being angled towards each other and spraying simultaneously.

By simultaneous use of more than one nozzle and the spraying nozzles being angled towards each other, a common jet is established. The common jet is established by the jets from the nozzles hitting each other at a certain distance from the spraying part of the nozzles.

With the establishment of the common jet, homogenous drop speed is achieved and the average drop speed will be quite high. A usual speed range may be between 1 and 4 meters per second. Further, the smallest drops will merge into larger drops upon impact and the largest drops will split into smaller drops. Hereby, a more homogenous jet is established with a drop size in the area of 150 to 250 μm and a variation in medium drop size as little as 20 μm.

Further, the farmer's pesticide expenses can be minimized which is important since the price of pesticides is soaring primarily due to taxes intended to reduce the use of pesticides.

Taxes on pesticides are a reaction to the increasing amounts of pesticides in the surrounding environments e.g. the groundwater, rainwater or lakes and streams.

In a second aspect of the invention, the number of spraying nozzles is three which allows a compact and symmetrical construction to be established around a centre nozzle. Especially, the possibility of the side jets targeting the centre jet from an equal distance will prevent or at least limit splashing and hereby the amount of pesticide being used.

It should be emphasised that the terms "pesticide or similar fluids" represent insecticide, fungicides, herbicide as well as growth control means or combinations hereof.

Other fluids, such as fertiliser, may be sprayed with the invention but with minor advantages as the drop size is less important. In a third aspect of the invention, the set of nozzles is positioned with a centre nozzle and at least one nozzle on each side, the side nozzles being angled towards the centre nozzle. Hereby, a set of nozzle with a homogenous jet may be established.

In a fourth aspect of the invention, the angle of a set of two nozzles is less than 180 degrees (parallel nozzles) and preferably between 176 and 145 degrees such as between 174 and 165 degrees.

In a fifth aspect of the invention, the sets of spraying nozzles are positioned on a horizontal boom. In a preferred embodiment of the invention, the sets of nozzles are units for supplementary mounting.

Usually, each set of spraying nozzles is angled at a few degrees in relation to the boom and to the moving direction of the boom. Hereby, the corners of the substantially triangular jet are positioned on each side of the boom. This means that the jet of each set is allowed to overlap without interfering with the others and it will usually extend almost to the middle of the next jet.

In a sixth aspect of the invention, said boom is movable in a vertical direction which allows further control of the spraying pattern.

In a seventh aspect of the invention, said control means includes on off control of said valve means. Hereby, it is possible to control the amount of pesticide being sprayed in an uncomplicated manner with a simple and low-cost control system.

The functionality of the valve means is that of opening and closing within a defined range of pressure which allows for the use of pre-pressure. With the use of pre- pressure, the valve means only needs a slight change in pressure to change position which creates a very fast reacting valve. In an eighth aspect of the invention, said control means includes continuous control of said valve means. Hereby, it is possible to control the amount of pesticide being sprayed in a very precise manner.

In a ninth aspect of the invention, the control means controls the valves on the basis of the speed of the sprayer and measurements of the pesticide flow in the system. Hereby, it is possible to control the jets in manner which ensures that optimal medium drop size can be optanined.

Further, it is possible with the computer means to control selected nozzles or sets of nozzles and hereby establish spraying patterns designed to a given situation such as variations in a field or a change in the weather conditions.

In a tenth aspect of the invention, the spraying parts of said at least two spraying nozzles are angled towards each other and said valve means controls the simultaneous spraying of the nozzles. Hereby, an advantageous embodiment has been obtained. Especially the possibility of creating a spraying system that allows changes in the amount of pesticide being sprayed during use is advantageous.

In a further aspect of the invention, said set of spraying nozzles is integrated in a casing, and the angling, between the spraying parts is fixed. This is advantageous since it prevents vibrations from causing unintended changes of the angling during use of the system.

In an even further aspect of the invention, the spraying nozzles are separate units of a set which makes for a system that is simple and easy to produce.

In another aspect of the invention, the spraying nozzles comprise a main body, a spraying part and a nozzle head. Hereby, it is possible to cast a nozzle by means of only a few very simple casting moulds instead of one complicated mould. In yet another aspect of the invention, the nozzle head comprises at least one groove which is clamped onto at least one elevation in the main body which creates an easy way of mounting the nozzle head and the spraying part on the main body.

In an additional aspect of the invention, said nozzle head comprises a wing-like projection on the side of the nozzle head, making it possible to mount the nozzle head without the use of tools. Further, reparations on the system or replacements of nozzle components can be carried out without tool use.

In an extra aspect of the invention, said at least one nozzle is a flat spray nozzle. With a flat spray nozzle, it is possible to create uniform drop distribution and a nozzle spray angle which is less dependent on pressure variations. Further, the nozzle type establishes smooth overlaps between the jets from the sets of nozzles.

Even further, the flat spray nozzle may be fitted with a hole plate whereby the drop size may be increased. The divided spraying part will be smaller as will the pressure and the use of pesticide.

The flat spray nozzle is very uncomplicated in its construction and is therefore very easy to produce in e.g. plastic.

In a last aspect of the invention, said nozzles are partially or totally made of plastic such as POM (PolyOxy-Methylen) which allows for low-weight nozzles. This is very important since too much weight can cause vibrations or resonance in the boom.

Further, the weight influences the fuel consumption of the self-propelled vehicle or the tractor trailing the boom.

The use of plastic also means that the nozzles may be quite low-priced compared to standard nozzles in other materials. It should be emphasised that the valve means may be integrated in the nozzles or be separate units connected to the nozzles.

Figures

The invention will be described in the following with reference to the figures in which

fig. 1 shows a number of nozzles placed on a boom,

fig. 2 shows the functionality of a nozzle,

fig. 3 shows a set of nozzles in a preferred embodiment of the invention,

fig. 4 shows a cross section of a jet from a set of nozzles,

fig. 5 shows the components of a nozzle according to a second embodiment of the invention,

fig. 6 shows a system for spraying pesticide,

figs. 7a to 7d show preferred embodiments of a control system,

fig. 8 shows details of the control system, and

fig. 9 shows a block diagram of the control system.

Detailed description

In a preferred embodiment, the invention relates to a system for spraying pesticide on agricultural fields and to sets of spraying nozzles to be used in the system. Fig. 1 shows a sprayer 1 comprising a number of nozzles 4a-4c placed on a boom 2 connected with a tank 6 containing pesticide. The sprayer 1 with the boom 2 and the tank 6 can be a self-propelled vehicle or trailed by a tractor.

The boom has a lifting means 7 with a lifting frame 5 for the boom 2 or sections 3a- 3c of the boom 2. The height of the boom 2 above the field may be changed by means of the lifting means 7 and since the boom is dived into sections (side and centre sections 2a, 2c and 2b, respectively), the side sections 2a, 2c can be raised to vertical position e.g. during transport to the fields.

Fig. 2 shows the functionality of a nozzle 16 spraying a jet 14, 15 of drops D. The nozzle comprises an interior space 12 of a container 11 filled with a liquid L which is pushed out through a hole 13 by a force F acting on a plate 10. The hole functions as the spraying part of the nozzle 16.

In a first phase, the liquid leaves the spraying part of the nozzle and expands into a liquid film 14. Later, the liquid enters the second phase in which it is converted into a cloud of drops 15 of different sizes. Characteristically, the cloud 15 will be composed in such a manner that the largest drops are positioned at the periphery and the smallest at centre of the jet.

Fig. 3 shows a set of nozzles 30 including three nozzles 16a- 16c in a preferred embodiment of the invention. Each of the three nozzles is fed with pesticide from a tank 31 through connections 29 such as pipes. The connections to a nozzle may preferably be through two connection branches 23 positioned on each side of the nozzle 16a- 16c. The connection branches 23 may connect with the connections 29 through press fits, threads or other mechanical methods of joining parts such as welding or soldering.

The nozzles are further connected to control means 20 with connections. The nozzles may also be fed with water and concentrated pesticide in separate connections from separate tanks. The mixing of the water and pesticide will then take place in the nozzles prior to spraying.

The connections between the nozzles on a boom may be established by a pipe connecting the first nozzle in a first set with the tank containing pesticide. The first nozzle in the first set is connected with the first nozzle in the second set by a pipe section and so forth.

The second nozzle in the first set is then connected with the tank and the second nozzle in the second set in the same manner and so forth.

The connection between the tank and the first nozzles by pipe sections establishes a single path for the pesticide in which the pressure on the fluid in the path is kept stable by pumping means. In the same manner, the second and third nozzles with pipe sections establish a second and third path. If more than three nozzles are used in each set, further paths must be established. However, an embodiment with several nozzles in a set being supplied from the same path is also possible.

In a preferred embodiment of the invention, the sets of nozzles are units for supplementary mounting on an existing boom in a spraying system. By using a number of sets of nozzles and connecting the sets with pipe sections as described above, it is possible to establish a spraying system by means of standardized components. The pipe sections between the nozzle sets are all of the same length and the nozzle sets are equally spaced apart on the boom. The length of the pipe sections may usually be in the range of 40 to 60 centimeters e.g. 50 centimeters.

In another embodiment of the invention, the three nozzles may be integrated in a housing including three spraying parts that are directed towards each other.

Fig. 4 shows the set of nozzles 30 with spraying parts 27 in a direction towards each other i.e. in positions where the spraying parts are not parallel but positioned at an angle of less than 180 degrees (parallel) and more than 90 degrees (perpendicular). In a preferred embodiment, the angle is between 165 and 174 degrees and the nozzles 16a- 16c are positioned less than 10 centimetres apart. Each of the three nozzles sprays a triangular jet 43, 44 with a thin depth and these jets 43, 44 meet in a position just beneath the nozzles 16a- 16c which creates a common jet 40. A cross section of the common jet 40 illustrates that the jet is uniform with a drop size varying from the centre and out but with less difference in regard to size. The varying of drop size is illustrated in the cross section of the common jet 40 with an inner section 41 and outer section 42 where the varying in drop size between the sections are uniform to a higher degree than usual.

Fig. 5 shows an embodiment of the nozzle in an exploded view (with further reference to fig. 3). The nozzle 16 includes a nozzle head 25 with an opening 54, a spraying part 27, a main body 21 with pipe branches 23, a needle valve 50 and an end cap 22. The figure does not show any seal rings between the components.

The nozzle head 25 and the spraying part 27 are fastened to the main body 21 by means of a groove 26 in the nozzle head 25 which is clamped onto an elevation 28 in the main body 21. With the clamping of the nozzle head 25 onto the main body 21, the spraying part 27 is pressed against the main body 21 and the nozzle head 25 allowing firm securing of the spraying part 27. The fastening of the nozzle head 25 is aided by a wing-like projection for a thumb 24 on the side of the nozzle head.

The end cap 22 is connected to the main body 21 by snap-locks or thread incorporated in the main body.

The nozzles are connected to one or more pipes following the boom in its entire length. Hereby, the pipes serve as suspension for the nozzles as well as the connection 29 to the tank 31 containing pesticide.

The needle valve 50 works as an on/off valve directing pesticide from the pipes to the spraying part. The needle valve includes a plate 51 which opens and closes the pesticide conduit in the main part 21 by e.g. 3 millimetres. The second plate 52 of the needle valve 50 is the contact face together with the end cap 22 for a spring (not shown in the figure) holding the needle valve 50 in a closed position when no force is applied. The two plates 51, 52 are connected by a central rod 53.

If the needle valve is in open position, fluid force is applied to the second plate 52 squeezing the spring together and moving the plate.

The functionality of the needle valve 50 is that the valve closes if the fluid pressure is less than a certain value in the pipes and opens when the pressure exceeds that value. By keeping a certain minimum of pressure in the pipes, the reaction time of the valve is decreased significantly.

Fig. 6 shows a preferred embodiment of a control system for spraying pesticide from a tank 70 containing pesticide. The system is divided into a tractor and a sprayer section (where the sections are divided on the figure by the dotted line 62).

The control system receives a number of measured values from different sensors such as Hall-sensors 64-66 measuring the speed of the tractor and flow sensors 70 measuring the amount of pesticide being sprayed. The Hall sensor 65 may measure the tractor speed by detecting the number of rotations of the tractor wheel by means of e.g. a magnet 66 mounted thereupon.

The tractor includes a computer 60 generally controlling the tractor and the farm machine being trailed. The person using the tractor may instruct the computer 60 by using an interface of the computer, e.g. a graphical user interface.

To control the functionality of the sprayer, and especially the state of each of the valves 71 in the nozzles 72 of the spraying system, the sprayer is provided with a job computer 68. The job computer 68 has connections 61, 63, 67 to the tractor computer 60 as well as to the sensors 64-66 and the valves 71. Some or all of the connections to and from the job computer may be data bus connections, such as a controlled area network CAN bus system, using two-cored cables. The CAN bus system allows easy on/off hooking of the sprayer and tractor.

The job computer 68 comprises software controlling the valves 71 on the basis of e.g. measured values and/or instructions from the tractor computer 60. Other parameters used in the job computer may be parameters defining the number of valves or the valve type. Further, GPS values from a satellite may be used. By changing the parameters of the software, it will be possible to design the control system for any type of spraying system.

Figs. 7a-d show preferred embodiments of a fluid system with an on/off control system of the valves.

The on/off control may be established in a number of ways so that each valve controls a single nozzle or a selection of nozzles. The on/off control includes throttle valves 81, on/off valves 82, drip preventing means 89 and nozzles 90 in nozzle sets 91. The throttle valves control the on/off valves 82 on the basis of an electric control signal 80.

In the first embodiment, each first nozzle of a set is included in a first part, each second nozzle of a set is included in a second part and each third nozzle of a set is included in a third part. As shown in fig. 1, the boom is divided into three sections 85, 86, 88 (3a-3c in fig. 1) and each section is controlled separately with a total of nine valves controlling the three parts in each of the three sections. Each of the nozzles is equipped with drip preventing means by means of the connections 83, 84, 87 to the on/off valves.

A second embodiment involves the use of a common throttle valve 81 for the nine on/off valves 82.

A third embodiment involves an on/off valve 82 for each nozzle 90 and a common throttle valve 81 without drip preventing means. A fourth embodiment involves a throttle valve 81 for each nozzle 90 and an on/off valve 82 for each section without drip preventing means.

Fig. 8 shows another preferred embodiment of a control system of the valves by means of which the position of each valve is controlled continuously.

The control system involves a hydraulic fluid circuit comprising a fluid tank or container 104 connected with a connection 105 to a cylinder 106 through a pump 103 and a throttle valve 101. The throttle valve receives an electric control signal from the rest of the control system 100 and hereby controls the cylinder position by the amount of fluid/pesticide pumped from the tank or container 104 to the cylinder 106. The cylinder position then controls the nozzles 107 or set of nozzles allowing for continuous change of the amount of pesticide being sprayed.

A continuously controlled valve system may also be achieved in an electric manner by replacing the hydraulic system with electric motors, such as step motors or linear motors, e.g. a solenoid which controls the nozzles mechanically.

Fig. 9 shows a block diagram 110-116 of an embodiment of the control system of a continuously controlled valve system. The resulting parameter Q (of block 115) represents the amount of pesticide sprayed on the fields and is established as the sum of a reference value defining the desired amount of pesticide Qref (block 110) in relation to the speed of the tractor and the actual flow amount of measured pesticide Q as the feedback value (block 116).

The result of the summing of Q and Qref is lead to a PID controller (block 111) which controls a motor (block 112) controlling a valve (block 113 and 114) with an integrated integral effect. The valve controls a nozzle in accordance with a performance curve for the nozzle (block 115). List

1. Sprayer

2. Boom

3a. First section of the boom (side section)

3b. Second section of the boom (centre section)

3c. Third section of the boom (side section)

4a. First nozzle on first section of the boom

4b. First nozzle on second section of the boom

4c. First nozzle on third section of the boom

5. Lifting frame for the boom

6. Tank containing pesticide

7. Lifting means

10 Plate

11 Container

12 Interior space

13 Hole

14 Liquid film

15 Cloud of drops

16, 16a- 16c. Nozzle

20 Control Means

21 Main body of a nozzle

22 End cap of a nozzle

23 Connection branch

24 Wing-like projection for a thumb

25 Nozzle head

26 Groove

27 Spraying part

28 Elevation

29. Connections such as pipes

30 Set of nozzles

31. Tank containing liquid such as pesticide 0 Common jet 1 Inner section of a common jet

42 Outer section of a common jet

43 Side jets 4 Centre jet

50 Needle valve

51 First plate

52 Second plate

53 Central rod connecting the plates

54 Opening in a nozzle head

60 Computer

61 Connection from computer to through joint

62 Dotted line dividing a tractor and a sprayer section

63 Through joint

64 Connection from computer to sensor

65 Hall sensor

66 Magnet in a Hall sensor

67 Connection to the job computer from through joint

68 Job computer

69 Connections to nozzles

70 Tank containing pesticide

71 Valves

72 Nozzles

80 Electric control signal

81 Throttle valves

82 On/off valves

83 , 84, 87. Connection

85 86, 88. Nozzle sections of a boom

89 Drip preventing means

90 Nozzles

91 Set of nozzles

10 0. Control system 101. Throttle valve

102.

103. Pump

104. Fluid tank or container

105. Connection

106. Cylinder

107. Nozzle or set of nozzles

110-116. Blocks in block diagram

D Drops or droplets

F Force

L Liquid or fluid

Claims

Patent Claims

1. System for spraying pesticide or similar fluids on agricultural fields, said system comprising

at least one container (6, 31) containing pesticide or similar fluids,

at least one set of spraying nozzles (30) said at least one set comprising at least two spraying nozzles (16, 16a, 16b, 16c) and said at least one set having connections (29) to said at least one container (6, 31),

characterized in that

said system further comprises control means (20) controlling the flow of pesticide through said connections (29) to said at least one set of spraying nozzles (30), and

the spraying parts (27) of said at least two spraying nozzles (16, 16a, 16b, 16c) are angled towards each other and spray simultaneously.

2. System for spraying pesticide on agricultural fields according to claim 1 characterized in that the number of spraying nozzles (16, 16a, 16b, 16c) in a set (30) is three.

3. System for spraying pesticide on agricultural fields according to claim 1 or 2 characterized in that the set of nozzles (30) is positioned with a centre nozzle (16b) and at least one nozzle on each side (16a, 16c), the side nozzles being angled towards the centre nozzle.

4. System for spraying pesticide on agricultural fields according to any of claims lto3 characterized in that the angle between a set of two nozzles (16, 16a, 16b, 16c) is less than 180 degrees and preferably between 176 and 145 degrees such as between 174 and 165 degrees.

5. System for spraying pesticide on agricultural fields according to any of claims l to 4 characterize d in that the sets of spraying nozzles (30) are positioned on a horizontal boom (2, 3a-3c).

6. System for spraying pesticide on agricultural fields according to claim 5 characterize d in that said boom (2, 3a-3c) is movable in a vertical direction.

7. System for spraying pesticide on agricultural fields according to claim 5 or 6 characteriz e d in that the nozzles (16, 16a, 16b, 16c) of a set (30) are positioned in a line, preferably substantially in parallel with said boom (2, 3a-3c).

8. System for spraying pesticide on agricultural fields according to claim 5, 6 or 7 chara c teri z ed i n that said boom (2, 3a-3c) is self- propelled or moved by a tractor or a similar farm machine.

9. System for spraying pesticide on agricultural fields according to any of claims l to 8 char acteri zed in that said nozzles (16, 16a, 16b, 16c) include valve means (50, 71, 82).

10. System for spraying pesticide on agricultural fields according to any of claims lto9 char acteriz ed in that the first nozzle in a set of nozzles is connected to the first nozzle of the next set of nozzles and so on by means of standardised connection means such as a pipe section of a given length.

11. System for spraying pesticide on agricultural fields according to any of claims ltolO characterized in that said control means (20) includes on/off control of said valve means (50, 71, 82).

12. System for spraying pesticide on agricultural fields according to any of claims ltolO characterized in that said control means (20) includes continuous control of said valve means (50, 71, 82).

13. System for spraying pesticide on agricultural fields according to claim 11 or 12 characterized in that the control means (20) controls the valves (50, 71, 82) on the basis of the speed of the sprayer and measurements of the pesticide flow in the system.

14. Set of spraying nozzles (30) used in a system for spraying pesticide on agricultural fields, said set comprising

valve means (50, 71, 82),

at least two spraying nozzles (16, 16a, 16b, 16c) with spraying parts (27),

characterized in that

the spraying parts (27) of said at least two spraying nozzles (16, 16a, 16b, 16c) are angled towards each other and said valve means (50, 71, 82) controls the simultaneous spraying of the nozzles.

15. Set of spraying nozzles according to claim 14 characterized i n that said set of spraying nozzles (30) is integrated in one casing.

16. Set of spraying nozzles according to claim 14 or 15 characterized in that the spraying nozzles are separate units of a set (30).

17. Set of spraying nozzles according to any of claims 14 to 16 charact e rize d in that said spraying nozzles (16, 16a, 16b, 16c) comprise a main body (21), a spraying part (27) and a nozzle head (25).

18. Set of spraying nozzles according to claim 17 c h ara c teriz e d i n that the nozzle head (25) comprises at least one groove (26) which is clamped onto at least one elevation (28) in the main body (21).

19. Set of spraying nozzles according to claim 17 or 18 characte ri ze d in that said nozzle head (25) comprises a wing-like projection (24) on the side of the nozzle head.

20. Set of spraying nozzles according to any of claims 14 to 19 characterize d in that said at least one nozzle is a flat spray nozzle.

21. Set of spraying nozzles according to any of claims 14 to 20 charact e rize d in that said nozzles are partially or totally made of plastic such as POM (PolyOxy-Methylen).

22. Method of spraying pesticide on agricultural fields, said method comprising the steps of:

feeding pesticide to at least two nozzles from at least one container,

controlling the amount of pesticide reaching each of the nozzles,

discharging said pesticide through a spraying part in each nozzles, and

spraying simultaneously in a direction towards each other.

3. Use of a set of spraying nozzles according to any of claims 14 to 21 and method according to claim 22 as a unit for supplementary mounting on an existing pesticide spraying system such as a boom.