A SPRAYER BOOM

Abstract: A sprayer boom (1) used for sending an atomised flow of liquid crop protecting agent by means of a pump from a storage container (5) over a crop (11) via a number of liquid jets (9) distributed along the boom (1). The boom (1) furthermore includes a blower (7) for, via a number of air orifices in a flexible hose (6) extending along the boom, sending out an airflow for protecting the atomised liquid against wind drifting. A nozzle (8) is fitted around each of the air orifices of the flexible hose. Thereby, the boom (1) is in operation able to create an optimally effective air curtain. Another advantage is that the exhaust ports of the flexible air hose (6) can be adapted to a given task quickly and easily.

Description: A Sprayer Boom The invention relates to a sprayer boom comprising at least one pump for, via a number of liquid jets distributed along the boom, sending an atomised flow of liquid crop protecting agent from a storage container over a crop, and at least one blower for, via a number of air orifices in a flexible air hose extending along the boom, sending out an airflow for protecting the atomised liquid against wind drifting. Crop protecting agents in form of spray liquids are largely used for protecting crops against attack of e.g. fungi and insects. However, crop protecting agents are in themselves polluting to the environment, and the applied volumes per unit area therefore must be reduced to an absolute minimum. For this reason, the spray liquid is today sent out through the liquid jets under high pressure in a cloud of finely atomised liquid. The extraordinarily fine liquid drops are deposited in an extremely thin layer on the crop surface so that the amount of spray liquid used can be reduced to the required quantity. However, the cloud of finely atomised spray liquid is extremely sensitive to wind drifting, and the wind can therefore relatively easily blow the cloud more or less away from the sprayed area. Thereby, the spraying becomes uneven, and damage can be made to adjoining areas. From Danish patent no. 156806 is known a field sprayer having a sprayer boom that besides liquid jets also has air jets for sending a flow of air in form of an air curtain down towards the crop in order to thereby protect the liquid cloud against wind drifting. The airflow furthermore opens the crop to the liquid cloud which therefore can penetrate into every part of the crop surfaces more easily and produce the desired effect. The air jets are fixed flat jets extending in the longitudinal direction of the boom. Patent application PCT/DK97/00325 describes a sprayer boom having round air jets disposed on a lattice boom. In this case, each air jet is designed in such a way that it in operation sends out a whirling airflow. On the sprayer boom known from Danish patent DK 167104, the air jets are disposed on a fixed, flexible air hose which during operation is inflated by the positive pressure that is necessary to force the air through the air jets at the desired velocity. Each of these jets are formed by oblong, rigid plate parts around an oblong exhaust port extending in the longitudinal direction of the boom. This design is simple and inexpensive. However, the air flows out via a relatively sharp- edged orifice in close proximity to the wall of the flexible hose whereby the air cannot obtain optimum conditions in order to be able to create an effective air curtain to protect the finely atomised spray liquid against wind drifting. The object of the invention is to provide a sprayer boom of the kind mentioned in the opening paragraph, the flexible air hose of which is arranged in such a way that the air blown out through the air hose during operation is made to create an optimally effective air curtain. A second object of the invention is to arrange the flexible air hose in such a way that its exhaust ports can be adapted to a given task quickly and easily. The novel and unique features according to the invention, whereby this is achieved, is the fact that a nozzle is fitted around at least one of the air orifices of the flexible hose. Thereby, the outflow of the air will advantageously take place at a distance from the wall of the flexible hose. In an advantageous embodiment, the nozzle can be shaped as a connection piece which is made of rubber or plastic and welded or glued onto the flexible hose. When a connection piece is made of a relatively flexible rubber or plastic, it cooperates easily with the flexible hose during operation without any risk of this hose being damaged during this . It is expedient to provide the connection pieces with internal and/or external thread so that they can be furnished with other detachably exchangeable nozzles. Thereby, the sprayer boom can be adapted to a given task quickly and easily. The thread can e.g. be round thread. The nozzle can also be a conic jet mounted directly on the flexible hose or screwed onto a threaded connection piece on the hose. By shortening such a conic jet with e.g. a pair of scissors or a knife, the size of the jet orifice can be adjusted as required. The nozzle can moreover be shaped in many different ways. The nozzle can in this way e.g. have a flat outlet extending in the longitudinal direction of the boom. Thereby, the air is spread evenly along the boom. In a second embodiment, a flow body can be disposed in the nozzle for optimally regulating the flow of the air through the nozzle. In an especially expedient embodiment, the nozzle can be shaped as a flexible pipe having louvers on each of the sides that are facing in the longitudinal direction of the boom. The louvers are in this case shaped in such a way that the air advantageously is blown down towards the crop and obliquely to the sides. Thereby, an advantage is obtained in that a dense and compact air curtain is created that has great ability to protect the finely atomised spray liquid against wind drifting. The invention will be explained in greater detail below, describing only exemplary embodiments with reference to the drawing, in which Fig. 1 is a perspective view of a sprayer boom according to the invention mounted on a tractor, Fig. 2 is a diagrammatic sectional view through the sprayer boom in fig. 1 during spraying of a crop, Fig. 3 is on a larger scale a fractional, axial sectional view of a threaded connection piece on a flexible air hose for the sprayer boom in figs. 1 and 2, Fig. 4 is an axial sectional view of an air jet screwed into the threaded connection piece in fig. 3, Fig. 5 is an axial sectional view of a conic jet mounted directly on the flexible air hose, Fig. 6 is an axial sectional view of a plain connection piece mounted directly on the flexible air hose and a flow body disposed in the connection piece, Fig. 7 is an axial sectional view of a plain connection piece mounted directly on the flexible air hose and inclined shovels disposed in the connection piece and serving for bringing the air flowing through into rotational motion, Fig. 8 is an axial sectional view of a flexible pipe screwed onto the connection piece in fig. 3 and provided with louvers along two diametrically opposite sides, and Fig. 9 shows the pipe in fig. 8 but rotated 90°. Fig. 1 shows a sprayer boom according to the invention designated generally by the reference numeral 1. The sprayer boom is mounted on a tractor 2 by means of a frame 3 with a backwards facing console 4. On the frame is mounted a storage container 5 for a liquid crop protecting agent. As shown, the sprayer boom is extending to both sides of the tractor. In the figure is furthermore shown a mainly horizontal flexible air hose 6 and a blower set 7 for during operation inflating the air hose and forcing the air out through the air jets. Fig. 2 is a diagrammatic sectional view through the main components of the sprayer boom, said components comprising partly the flexible air hose 6 having nozzles 8, partly liquid jets 9 disposed on a liquid manifold 10. The sprayer boom is used for treating a crop 11 with the crop protecting agent in the storage container 5. When the sprayer boom is in operation, the crop protecting agent is by means of a pump (not shown) forced out of the liquid jets under pressure in finely atomised form down towards the crop 11. At the same time, the blower set 7 is sending a strong airflow down towards the crop. The airflow sucks the finely atomised spray liquid along with it and leads the liquid, as indicated by the arrows, down into the crop. This phenomenon is illustrated in the figure, in which it can be seen that the liquid stream and the airflow respectively are expanding in the shape of a fan after having left the respective jets. Thereby, the liquid stream and the airflow are mixed under the jets, and the crop protecting agent is spread evenly into the crop that during this is opened by the airflow. Fig. 3 shows a first embodiment of the nozzle 8 in figs. 1 and 2 in form of a threaded connection piece 12 having internal and external round threads 13. In this case, the connection piece has a flange 14 which by means of welding or gluing (not shown) is joined with the wall 15 of the flexible air hose 6, only a fractional view of said wall is shown in the figure. By means of the connection piece 12, the air is made to flow out freely at a distance from the wall 15 of the flexible air hose. Another advantage is that the sprayer boom as required now can be provided with other nozzles suited for a given task easily and conveniently. Fig. 4 shows an example of such a second nozzle which in this case is an air jet 16. Depending on the spraying task to be performed, jets having large or small jet orifices can be inserted. In fig. 5, a plain conic jet 17 is mounted directly on the wall 15 of the flexible air hose 6. The jet orifice can be adapted by shortening the conical jet by a big or small bit. Fig. 6 shows a plain, cylindrical connection piece 18 which is also mounted directly on the wall 15 of the flexible air hose 6. In the connection piece, there is by means of flat transverse sections 20 disposed a drop-shaped flow body 19 for ensuring the air a mainly laminar flow through the connection piece and a simultaneously advantageous acceleration of the flow velocity. Fig. 7 shows a second plain, cylindrical connection piece 21 mounted directly on the wall 15 of the flexible air hose 6. In the connection piece are disposed inclined shovels 22 for bringing the air flowing through into whirling motion. A nozzle is shown in fig. 8 and in fraction in fig. 9 in form of an air pipe 23 screwed onto the threaded connection piece 12 in fig. 3. In the case shown, the pipe is closed by means of a bottom 24. On diametrically opposite sides, seen in the longitudinal direction of the sprayer boom, the pipe is provided with a number of louvers 25 that guide the airflow downwards and to the sides along the boom. Thereby, an advantageously dense, continuous and compact air curtain is obtained that has a small extent in the direction of motion. In a variant of this embodiment, the air pipe 23 can besides the louvers 25 also have one or more jets (not shown) disposed on its bottom 24. The pipe can furthermore be bent expediently in relation to the configuration of the discharged liquid cloud. The invention is described above and shown in the drawing on the assumption that the nozzles were round. Within the scope of the invention, the nozzles can however have any other suitable cross sectional shape. They can in this way be e.g. elliptical, rectangular, or flat. The connection pieces do not have to have the same cross sectional shape in their entire longitudinal extension. They can e.g. be round at the joint with the flexible hose and flat at the outlet. In the examples shown and described, the threaded connection pieces are provided with round thread. In other cases, they can be provided with other kinds of threads or with other means for detachable mounting of other nozzles. The material the nozzles are made of can be rubber or plastic, as mentioned. But for the manufacture, other suitable materials can also be used, e.g. metal.

Claims: Claims 1. A sprayer boom (1) comprising at least one pump for, via a number of liquid jets (9) distributed along the boom, sending an atomised flow of liquid crop protecting agent from a storage container (5) over a crop (11), and at least one blower (7) for, via a number of air orifices in a flexible air hose (6) extending along the boom, sending out an airflow for protecting the atomised liquid against wind drifting, characterised in that a nozzle (8) is fitted around at least one of the air orifices of the flexible hose. 2. A sprayer boom according to claim 1, characterised in that the nozzle is a connection piece (12) . 3. A sprayer boom according to claim 1 or 2 , characterised in that the nozzle is welded or glued onto the hose (6) . 4. A sprayer boom according to claim 1, 2 or 3, characterised in that the nozzle is made of rubber or plastic. 5. A sprayer boom according to any one of the claims 1 - 4, characterised in that the nozzle is shaped as a jet (16) . 6. A sprayer boom according to any one of the claims 1 - 5, characterised in that the nozzle (17) is conic. 7. A sprayer boom according to any one of the claims 1 - 6, characterised in that the nozzle (23) has louvers (25) on each of the sides that are facing in the longitudinal direction of the boom (6) . 8. A sprayer boom according to any one of the claims 1 - 7, characterised in that the nozzle (8) has a flat outlet extending in the longitudinal direction of the boom (6) 9. A sprayer boom according to any one of the claims 1 - 8, characterised in that the nozzle is a threaded connection piece (12) . 10. A sprayer boom according to any one of the claims 1 - 4, characterised in that the nozzle is a tubular connection piece 18, and that a flow body (19) is disposed in this connection piece. AMENDED CLAIMS [received by the International Bureau on 02 June 2000 (02.06.00); original claims 1 to 10 replaced by new claims 1 to 10 (2 pages)] 1. A sprayer boom (1) comprising at least one pump for, via a number of liquid jets (9) distributed along the boom, sending an atomised flow of liquid crop protecting agent from a storage container (5) over a crop (11), and at least one blower (7) for, via a number of air orifices in a flexible air hose (6) extending along the boom, sending out an airflow for protecting the atomised liquid against wind drifting, characterised in that a connecting piece (12) is fitted around at least one of the air orifices of the flexible hose. 2. A sprayer boom according to claim 1 , characterised in that the connection piece is a threaded connection piece (12) . 3. A sprayer boom according to claim 1 or 2 , characterised in that a nozzle (16; 24) is mounted upon the connection piece (12) . 4. A sprayer boom according to claim 3, characterised in that the nozzle is shaped as a jet (16) . 5. A sprayer boom according to claim 3, characterised in that the nozzle is conic. 6. A sprayer boom according to claim 3, characterised in that the nozzle (23) has louvers (25) on each of the sides that are facing in the longitudinal direction of the boom (6) . A sprayer boom according to any one of the claims 1 - 4, characterised in that a flow body (19) is disposed in the connection piece and/or the nozzle. 8. A sprayer boom according to any one of the claims 2 - 7, characterised in that the nozzle has a flat outlet extending in the longitudinal direction of the boom (6) 9. A sprayer boom according to claim 3 , characterised in that the connecting piece itself is formed as a nozzle. 10. A sprayer boom according to any of the claims 1 - 9, characterised in that the connection piece (12) is made of rubber or plastic and is welded or glued onto the hose (6) .

Inventors: HEDEGAARD ALBERT, HEDEGAARD, ALBERT
Applicants: HEDEGAARD ALBERT, HEDEGAARD, ALBERT
Application year: 2000
Main classification: A01M7
IPC codes: A01M7, B05B7