WO2019151850A1

WO2019151850A1 - Device and method for spreading a liquid over a field

Info

Publication number: WO2019151850A1
Application number: PCT/NL2019/000003
Authority: WO
Inventors: Hendrikus Hermanus VOSSEBELD
Original assignee: Vossebeld Hendrikus Hermanus
Priority date: 2018-02-05
Filing date: 2019-01-30
Publication date: 2019-08-08
Also published as: NL1043136B1; NL1043136A

Abstract

Device for spreading a liquid over a field, comprising a vehicle and a spraying device mounted on the vehicle and comprising a spray boom provided with spray nozzles, characterized in that at least a part of the spray boom is able to rotate relative to the vehicle in a horizontal plane about a vertical rotation axis through a relatively large angle of at least 30°. Also method for spreading a liquid over a field by means of such a device, characterized in that, during a pass, the at least one part of the spray boom rotates relative to the vehicle within the relatively large angle such that the horizontal rotational position of the at least one part of the spray boom relative to the field remains substantially constant. Therein the at least one part of the spray boom can rotate relative to the vehicle within the relatively large angle under the influence of the mass inertia of the at least one part of the spray boom and/or can be rotated within the relatively large angle by means of first means provided for this purpose. The horizontal speeds of the spray heads relative to the field thus remain equal relative to each other and constant, at least as long as an end stop is not come up against and within determined limits, and a uniform spreading of the liquid over the field can be achieved within strict limits. The forces on the spray boom and the other parts can thus also remain limited, so that it is possible to suffice with a relatively light and simple embodiment of the spray boom and mounting thereof.

Description

Device and method for spreading a liquid over a field

Field of the invention

The invention relates to a device for spreading a liquid over a field, comprising a vehicle and a spraying device mounted on the vehicle and comprising a spray boom provided with spray nozzles. The invention also relates to a method for spreading a liquid over a field by means of such a device.

Background of the invention

Such devices, generally referred to as field sprayers, are known in agriculture in diverse embodiments, self-propelling or drawn. A field sprayer comprises a spray boom provided with spray nozzles, generally referred to as spray heads, whereby a spraying agent, for instance liquid fertilizer, a crop protection agent such as a herbicide or pesticide, or earth foam, can be distributed over a field. During spraying the spray boom is folded out and then extends transversely of the direction of travel of the vehicle.

The spraying agent has to be distributed over the field uniformly and in a desired quantity per unit area, within determined limits. It is important here for the horizontal speeds of the spray heads relative to the field to remain equal relative to each other and constant, within determined limits. This is impossible or at least increasingly difficult to comply with with known field sprayers due to the ever increasing operating widths and the increasingly strict requirements in respect of the quantity of spraying agent spread per unit area and the uniform distribution thereof.

Bends in a pass result in speed differences between the spray heads. The quantity of spraying agent spread per unit area is inversely proportional to the speed of a spray head. It is possible that too little spraying agent is then spread in an outside bend, and conversely too much in an inside bend. When the vehicle takes a bend with a radius equal to the length of the spray boom, the speed of a spray head in the outside bend is for instance roughly 3 times greater than the speed of a spray head in the inside bend. Because additional course corrections are furthermore usually necessary in bends, the relative differences in speed become even greater there.

Uneven terrain results in all sorts of movements and forces which can be transmitted from the vehicle to the spray boom. Known field sprayers have all sorts of provisions for absorbing undesired movements and forces in vertical direction, such that they are not transmitted, or are at least transmitted to limited extent, to the spray boom. In known field sprayers however, movements and forces in horizontal direction are transmitted, or at least transmitted to a great extent, from the vehicle to the spray boom. This in turn results in changes and relative differences in the horizontal speeds of the spray heads relative to the ground surface, and in non-uniform spreading of the spraying agent.

In known field sprayers it is attempted with systems varying from simple to advanced to always return a horizontally rotated spray boom to a horizontal right-angled position relative to the vehicle as quickly as possible, wherein great relative differences in the horizontal speeds of the spray heads relative to the ground surface result. In known field sprayers the avoiding of obstacles, passes along plot boundaries which are not straight, and course corrections also cause relatively great changes and relative differences in the horizontal speeds of the spray heads relative to the ground surface, this resulting in a spreading of the spraying agent with a relatively high degree of non-uniformity.

A spray boom can generally be folded in wholly or partially, for instance for transport by road or if a smaller operating width is desired. The extremities of the spray boom can usually also pivot in resilient manner relative to the other part of the spray boom. When an extremity runs into an obstacle, this extremity can yield and swing away, whereby damage can be prevented or at least reduced, which is referred to as‘obstacle guard’. If work is however being performed with a partially folded-in spray boom and an obstacle is run into, this obstacle guard does not work, and great damage can still be caused. When a plot is being worked, a substantial portion of the time is used to keep manoeuvring the field sprayer back into a correct position before a pass can be started, in the corners of the plot and while turning on the headlands. This turning and manoeuvring has to be done with the necessary caution, since excessive forces can otherwise occur on the spray boom and the other parts. A comer of a plot with an inner angle smaller than 90° is difficult to spray, and cannot be sprayed uniformly, with known field sprayers, resulting in overdosing and/or underdosing and additional wheel tracks at this location, and additional loss of time.

In order to be able to absorb movements and forces in horizontal direction a spray boom and mounting thereof with a relatively heavy form are opted for in a number of known field sprayers. This however results in more undesired track formation and higher costs. Furthermore, although undesired movements of the spray boom in the horizontal plane are reduced by the relatively great mass inertia of the heavier construction, they will continue to occur. A spring-mounted and/or damped mounting of the spray boom, for instance by means of gas springs with built-in damping, a rubber-like material or mechanical springs with hydraulic damping, is usually opted for. When the spray boom rotates in the horizontal plane from a neutral position, a counterforce follows immediately, which increases the bigger the rotation of the spray boom relative to the neutral position is. Rotation of the spray boom back to the neutral position is damped to greater or lesser extent.

The maximum horizontal rotation angle of the spray boom of such field sprayers is relatively small, with a hard end stop. The counter- force in horizontal rotation of the spray boom from the neutral position has to be relatively great in order to quickly return the spray boom to the neutral position, and to prevent the spray boom coming up against the hard end stop. All of this results in undesired, relatively great forces on the spray boom and the other parts.

DE10314686A1 for instance describes the controlling of horizontal movements of a spray boom by means of hydraulic cylinders and accumulators. When the spray boom rotates in a horizontal plane from a neutral position, a counterforce follows immediately. This behaviour is very similar to that of a system with damped gas springs. Also known in addition to such a passively controlled system are actively controlled systems. EP2064948A2 thus describes the use of hydraulic cylinders, wherein horizontal movements of the spray boom are damped hydraulically and corrected by an oil flow running through a conduit system and adjustable choke valves. Choke valve-based systems have the drawback that, in the case of more rapid horizontal movements of the spray boom, the counterforces required increase exponentially. DE102015113721A1 and EP2837285A1 describe systems wherein the horizontal rotation of the spray boom from a neutral position is measured with sensitive sensors, after which an electronic control unit calculates a matching signal which is transmitted to control valves and/or adjusting motors and/or electrically controllable dampers. This measuring, calculating and controlling has to take place continuously, rapidly and with great accuracy, for which purpose durable and expensive equipment is required.

In summary, in known field sprayers with a relatively small maximum horizontal rotation angle of the spray boom and a hard end stop, horizontal rotation of the spray boom from a neutral position relative to the vehicle is reacted to rapidly and with relatively great counterforces, which results in great forces on the spray boom and the other parts, necessitates a spray boom and mounting thereof with a relatively heavy form and/or demands and/or requires a less or a more complex spring system and/or damping and/or requires an expensive electronic control, wherein a uniform spreading of a spraying agent within strict limits is, nevertheless or precisely for this reason, not achieved.

The invention now provides a solution which does not have said drawbacks, or at least does so to lesser extent, and in addition has a number of advantages of its own.

Summary of the invention

The invention provides a device for spreading a liquid over a field, comprising a vehicle and a spraying device mounted on the vehicle and comprising a spray boom provided with spray nozzles, characterized in that at least a part of the spray boom is able to rotate relative to the vehicle in a horizontal plane about a vertical rotation axis through a relatively large angle of at least 30°. The invention also provides a method for spreading a liquid over a field by means of such a device, characterized in that, during a pass, the at least one part of the spray boom rotates relative to the vehicle within the relatively large angle such that the horizontal rotational position of the at least one part of the spray boom relative to the field remains substantially constant. The horizontal speeds of the spray heads relative to the field thus remain equal relative to each other and constant, at least as long as an end stop is not come up against and within determined limits, and a uniform spreading of the liquid over the field can be achieved within strict limits. The forces on the spray boom and the other parts can thus also remain limited, so that it is possible to suffice with a relatively light and simple embodiment of the spray boom and mounting thereof.

‘Horizontal’ and‘vertical’ are always understood in the context of the invention to mean respectively‘in a position of use at least substantially horizontal, or at least substantially parallel to the field’ and‘in a position of use at least substantially vertical, or at least substantially perpendicularly of the field’.

Brief description of the drawings

The invention is elucidated hereinbelow on the basis of non-limitative exemplary embodiments.

In the drawings:

figure 1 shows the spreading of a spraying agent in a non-straight pass by means of a prior art field sprayer;

figure 2 shows the spreading of a spraying agent in a non-straight pass by means of a field sprayer according to the invention;

figure 3 shows a top view of the field sprayer according to the invention with outer spray boom parts in a neutral horizontal rotational position and a top view of the field sprayer according to the invention with the outer spray boom parts rotated relative to the neutral horizontal rotational position; and

figure 4 shows a partial top view of the field sprayer according to the invention with the outer spray boom parts rotated relative to the neutral horizontal rotational position. Exemplary embodiments

The device (1) according to the invention shown in the drawings comprises a vehicle (3) and a spraying device mounted on the vehicle (3). The vehicle (3) is here drawn by a tractor (not shown). In other embodiments the vehicle can also be self-propelling. The spraying device comprises a spray boom (4) provided with spray nozzles (5). The spray boom (4) comprises here two outer parts (6, 6’) which can each rotate relative to the vehicle (3) in a horizontal plane about a vertical rotation axis (8, 8’) through relatively large angles (a, a’), here each 60°, and an inner part (7) with a fixed horizontal rotational position relative to the vehicle (3). In a simpler embodiment the spray boom can also consist of a single part which can rotate about a single vertical rotation axis.

The device (1) here also comprises first means (9) for rotating the two outer parts (6, 6’) of the spray boom (4) relative to the vehicle (3) in the horizontal plane about the vertical rotation axes (8, 8’). The device (1) here also comprises second means (not shown) for determining the horizontal rotational positions of the two outer parts (6, 6’) of the spray boom (4) relative to the vehicle (3), and also third means for determining the horizontal rotational positions of the two outer parts (6, 6’) of the spray boom (4) relative to the field (2).

Figure 1 shows a method for spreading a spraying agent in a non-straight pass by means of a prior art field sprayer. When taking the bends, the horizontal rotational position of the whole spray boom relative to the vehicle always remains at least substantially constant, this being at least substantially equal to a neutral, right-angled position relative to the main axis of the vehicle. Because of the considerable relative differences in speed of the spray heads which occur, the spraying agent is here by no means spread uniformly. Relatively great forces also result on the spray boom and the other parts of the field sprayer when the bends are taken due to the mass inertia of the spray boom.

Figure 2 shows a method for spreading a spraying agent in a non-straight pass (10) according to the invention. When taking the bends, the two outer parts (6, 6’) of the spray boom (4) rotate relative to the vehicle (3) in the horizontal plane about the vertical rotation axes (8, 8’), such that the horizontal rotational positions of the two outer parts (6, 6’) of the spray boom (4) relative to the field (2) remain at least substantially constant. At least substantially no relative differences in speed of the spray nozzles (5) thus occur, and the spraying agent is here spread at least substantially uniformly.

In order to keep the horizontal rotational positions of the two outer parts (6, 6’) of the spray boom (4) relative to the field (2) at least substantially constant, according to the invention use is now conversely made of the mass inertia of the outer parts (6, 6’) of the spray boom (4). It is precisely this mass inertia which contributes here to keeping the rotational positions of the two outer parts (6, 6’) relative to the field (2) constant. If the outer parts (6, 6’) are able to rotate relative to the vehicle (3) without friction and an end stop is not come up against, it is also the case here that, in principle, no horizontal forces on the spray boom (4) and the other parts of the device (1) result when a bend is taken.

In order to correct small variations from the desired horizontal rotational positions relative to the field (2) use can be made of the first means (9) for the purpose of cautiously rotating the two outer parts (6, 6’) to these desired horizontal rotational positions relative to the field (2), wherein only small forces occur on the spray boom (4) and the other parts. Use can be made here of the third means for the purpose of determining these small variations from the horizontal rotational positions of the two outer parts (6, 6’) relative to the field (2).

When the rotation angles become large and there is a risk of the end stops being come up against, use can be made of the first means (9) for, once again cautiously, rotating the second outer parts (6, 6’) back to more right-angled rotational positions relative to the vehicle (3), wherein once again only small forces occur on the spray boom (4) and the other parts of the device (1). Use can be made here of the second means for the purpose of determining the horizontal rotational positions of the two outer parts (6, 6’) relative to the vehicle (3).

During straight passes the horizontal rotational positions of the two outer parts (6, 6’) relative to the vehicle (3) can always remain at least substantially constant, this generally being at least substantially equal to neutral, right-angled positions relative to the main axis (11) of the vehicle (3), see left-hand part of figure 3. In a bend with the two outer parts (6, 6’) in the extreme rotational positions, see right-hand part of figure 3 and figure 4, the working width of the device (1) varies only a few percent from the working width with the two second outer parts (6, 6’) in the neutral, right-angled rotational positions. After taking a bend and returning to a straight part of a pass, the two outer parts (6, 6’) can be slowly moved back to the neutral, right-angled rotational positions by means of the first means (9), such that the relative speed differences of the spray nozzles (5) remain relatively small and within given limits.

When an obstacle is run into with a (partially) folded-in spray boom (4), the outer part (6, 6’) of the spray boom (4) in question can swing away about the vertical rotation axis (8, 8’) in question, whereby damage can be prevented or at least reduced. An additional obstacle guard is thus formed by the vertical rotation axes (8, 8’) lying close to the vehicle (3).

During the turning and manoeuvring, before a pass can be started, in the comers of the field, and while turning on the headlands the two outer parts (6, 6’) of the spray boom (4) can be rotated relative to the vehicle (3) by means of the first means (9) through the relatively large angles (a, a’) of 60° each. It is thus possible to manoeuvre much more quickly compared to known field sprayers with a relatively small maximum horizontal rotation angle of the spray boom. A corner of a field with an inner angle smaller than 90° can thus for instance also be sprayed more uniformly, with less overdosing and/or underdosing.

Claims

1. Device (1) for spreading a liquid over a field (2), comprising a vehicle (3) and a spraying device mounted on the vehicle and comprising a spray boom (4) provided with spray nozzles (5), characterized in that at least a part (6, 6’) of the spray boom is able to rotate relative to the vehicle in a horizontal plane about a vertical rotation axis (8, 8’) through a relatively large angle (a, a’) of at least 30°.

2. Device as claimed in claim 1, characterized in that the at least one part (6, 6’) of the spray boom is able to rotate through the relatively large angle (a, a’) at least substantially without friction.

3. Device as claimed in claim 1 or 2, characterized in that the device also comprises first means (9) for rotating the at least one part (6, 6’) of the spray boom (4) relative to the vehicle (3) through the relatively large angle (a, a’).

4. Device as claimed in any one of the claims 1-3, characterized in that the device also comprises second means for determining the horizontal rotational position of the at least one part (6, 6’) of the spray boom relative to the vehicle (3).

5. Device as claimed in any one of the claims 1-4, characterized in that the device also comprises third means for determining the horizontal rotational position of the at least one part (6, 6’) of the spray boom (4) relative to the field (2).

6. Method for spreading a liquid over a field (2) by means of a device (1) comprising a vehicle (3) and a spraying device mounted on the vehicle and comprising a spray boom (4) provided with spray nozzles (5), wherein at least a part (6, 6’) of the spray boom is able to rotate relative to the vehicle in a horizontal plane about a vertical rotation axis (8, 8’) through a relatively large angle (a, a’) of at least 30°, characterized in that, during a pass (10), the at least one part (6, 6’) of the spray boom rotates relative to the vehicle (3) within the relatively large angle (a, a’) such that the horizontal rotational position of the at least one part (6, 6’) of the spray boom relative to the field (2) remains at least substantially constant.

7. Method as claimed in claim 6, characterized in that the at least one part (6, 6’) of the spray boom rotates relative to the vehicle (3) within the relatively large angle (a, a’) under the influence of the mass inertia of the at least one part (6, 6’) of the spray boom.

8. Method as claimed in claim 6 or 7, characterized in that the at least one part (6, 6’) of the spray boom is rotated relative to the vehicle (3) within the relatively large angle (a, a’) by means of first means (9) provided for this purpose.

9. Method as claimed in any one of the claims 6-8, characterized in that the method also comprises of determining the horizontal rotational position of the at least one part (6,

6’) of the spray boom relative to the vehicle (3) by means of second means provided for this purpose.

10. Method as claimed in any one of the claims 6-9, characterized in that the method also comprises of determining the horizontal rotational position of the at least one part (6, 6’) of the spray boom relative to the field (2) by means of third means provided for this purpose.

11. Method as claimed in any one of the claims 6-10, characterized in that the method also comprises of rotating the at least one part (6, 6’) of the spray boom relative to the vehicle (3) within the relatively large angle (a, a’) to a desired horizontal rotational position relative to the vehicle (3).

12. Method as claimed in any one of the claims 6-11, characterized in that the method also comprises of rotating the at least one part (6, 6’) of the spray boom relative to the vehicle (3) within the relatively large angle (a, a’) to a desired horizontal rotational position relative to the field (2).