DEVICE FOR SPRAYING A LIQUID ON A CROP

Abstract: A device (1) for spraying a liquid on a crop, comprising a frame (2), at least one liquid spray nozzle (11) connected to the frame (2) and coupled to a line (6) supplying liquid under pressure, and at least one air nozzle (3) arranged close to the liquid spray nozzle (11) and coupled to a line (5) supplying air, which air nozzle (3) has a discharge opening (9) pointing substantially in the same direction as the liquid spray nozzle (11), while a directed air current discharged by the air nozzle (3) can absorb a flow of liquid sprayed by the liquid spray nozzle (11). In addition the air nozzle (3) has a slot-like discharge opening (9) that discharges a flat, directed current of air.

Description: DEVICE FOR SPRAYING A LIQUID ON A CROP The invention relates to a device for spraying a liquid on a crop, comprising a frame, at least one liquid spray nozzle connected to the frame and coupled to a line supplying liquid under pressure, and at least one air nozzle arranged close to the liquid spray nozzle and coupled to a line supplying air, which air nozzle has a discharge opening pointing substantially in the same direction as the liquid spray nozzle, while a directed air current discharged by the air nozzle can absorb a flow of liquid sprayed by the liquid spray nozzle. Such a device having a number of nozzles, whereby each liquid spray nozzle is arranged in the middle of a cylinder shaped air nozzle, is known. Compared to spray devices whereby the liquid is sprayed under pressure directly out of a spray nozzle onto the crop, this known device has the advantage that due to the extra air current supplied the sprayed liquid penetrates better ' between the crop and is applied more evenly. The invention has for its object to further improve such a known device. This is achieved according to the invention because the air nozzle has a slot-like discharge opening that discharges a flat, directed current of air. It has been found that penetration into the crop is greatly improved as a result of this. In a preferred embodiment this has the consequence that the same result can be achieved with a third of the amount of liquid otherwise normally used. As a result, in the case that for example the device comprises a spray boom with a number of spray nozzles arranged behind a tractor, this tractor also carrying a storage tank for the liquid to be sprayed, an area of crop three times as large can be treated per tank filling. This achieves a considerable time saving. - 2 - Trials have also indicated that, per unit of area of the crop to be sprayed, less active substance need be present in the liquid. This active substance is for example a pesticide. This advantage can be attributed to the very 5 good dispersal of the liquid. In this way a direct saving is thus achieved in the cost of the liquid to be sprayed, which can amount to many tens of thousands of guilders per company per year. Furthermore, in the case of pesticides, pollution of the environment is greatly limited. 10. A further developed preferred embodiment is characterized in that the liquid spray nozzle is of the type discharging a flat liquid screen and is arranged such that it discharges a liquid screen directed virtually parallel to the flat air current. As a result the sprayed 15 liquid is discharged evenly over the width of the air current, thus ensuring a very good dispersal. The liquid spray nozzle and the air nozzle can hereby be arranged in a favourable manner at a small distance from each other. The liquid spray nozzle thus remains separately 20 accessible so that in the case it malfunctions no disassembly operation need be performed. It has been found that an embodiment whereby the nozzles are directed slanting downwards and the liquid spray nozzle is arranged beneath the air nozzle produces 25_- particularly good results. Because of the lower pressure in the air current the sprayed liquid is taken up automatically into this air current. Because the air current flowing out above the sprayed liquid forms as it were a "shield" to what is above it, wind has little or no 0 influence on the result of the spray treatment. The invention will be explained further in the following description with reference to embodiments shown in the figures . Fig. 1 shows a perspective view of a device according 5 to the invention. Fig. 2 shows a partly broken away perspective detail view of a nozzle system according to a first embodiment. Fig. 3 shows a view corresponding with fig. 2 of a second embodiment. 5 The spraying device 1 comprises a frame 2 that is connected by means of suitable mountings to the lift apparatus of a tractor 15. Arranged on the frame 2 are a number of nozzles 3 according to the invention. Air is supplied to each of these nozzles via air hoses 5. These 10 hoses are coupled to an air fan 4 which is driven in a manner per se known by the power take-off of the tractor 15. Further coupled to frame 2 is a liquid pump (not shown) which feeds liquid from the storage tank 7 to nozzles 3 via liquid hoses 6. By moving the spray device 1 15 using the tractor 15 in a manner per se known over a piece of land planted with crops, the liquid can be sprayed from the storage tank 7 onto the crops. The spray nozzle 3 comprises an air nozzle and a liquid spray nozzle. The air nozzle is formed by a cap 8 20 having a round inlet connection 14 and a slot-like discharge opening 9. The air hose 5 is coupled by means of a clamp 16 to the inlet connection of cap 8. Cap 8 has a form such that a uniform transition occurs from the round inlet opening 14 to the slot-like discharge opening 9, so 25 that the nozzle can discharge a flat, directed current of air 10. Underneath air nozzle 8 is arranged liquid nozzle 11. The discharge opening of this liquid nozzle 11 has the form of a slot 12, so that this per se known liquid nozzle 11 can discharge the liquid supplied via the line 6 in the 30 form of a screen 13. The liquid spray nozzle 11 is arranged such that it discharges a liquid screen that is directed virtually parallel to the flat air current 10. Due to the lower static pressure in the flowing air, the liquid is absorbed 35 automatically into the air current. The liquid spray nozzle 11 can if required be directed at a small angle to the air nozzle, so that the liquid is sprayed directly into the air current. The same effect is obtained with an upper surface of the air nozzle directed 5 slanting towards the slot. The air current is thereby dir -ct'ed slightly downward, so that the liquid is sprayed Into: t:he air current. The liquid spray nozzle 11 is dire_ct_Ly accessible, so that in the case of malfunction it can he-, reached without further disassembly operations. 10. With the nozzle 20 from fig. 3 the liquid spray nozzle 23 is arranged inside the cap 26 of the air nozzle. The liquid feed hose 21 is guided inwards via an opening 22 in the cap 26. The jet of liquid 24 discharged by nozzle 23 is already mixed in the cap 26 " of 'the air nozzle with the 15 air supplied via the hose 5. The air current 25 flowing out of the slot-like opening 27 of air nozzle 20 to the outside already contains the finely dispersed liquid from nozzle 23. Nozzle 23 can be a so-called slot nozzle, and this, 0 particularly when this liquid spray nozzle is arranged very close to the discharge opening 27, is favourable for good dispersal. If the liquid nozzle is arranged very close to the inlet side of cap 27, it can also take the form of a nozzle that is circular spraying.

Claims: Claims 1. Device for spraying a liquid on a crop, comprising a frame, at least one liquid spray nozzle connected to said frame and coupled to a line supplying liquid under pressure, and at least one air nozzle arranged close to 5 said liquid spray nozzle and coupled to a line supplying air, said air nozzle having a discharge opening pointing substantially In the same direction as said liquid spray nozzle, while a directed air current discharged by said air nozzle can absorb a flow of liquid sprayed by said liquid 10 spray nozzle, characterized in that the air nozzle has a slot-like discharge opening that discharges a flat, directed current of air. 2. Device as claimed in claim 1, characterized in that the liquid spray nozzle is of the type discharging a flat 1-5 liquid screen and is arranged such that it discharges a liquid screen directed virtually parallel to the flat air curren . 3. Device as claimed in claim 2, characterized in that the liquid spray nozzle and the air nozzle are arranged at 20 a small distance from each other. 4. Device as claimed in claim 3, characterized in that the nozzles are pointed slanting downwards and the liquid nozzle is arranged under the air nozzle.

Inventors: HOMBURG FRITS, HOMBURG, FRITS
Applicants: HOMBURG MACHINEHANDEL, HOMBURG MACHINEHANDEL B.V.
Application year: 1986
Main classification: A01M7
IPC codes: A01M7, B05B7