Spray unit

Abstract

The present invention relates to a spray unit including a shaft (10), a disk (20), a liquid applicator (40), and a spray directing assembly (50). The disk is configured to rotate about the shaft centered on the center of the disk. The liquid applicator is configured to apply liquid to a surface of the disk. The spray directing assembly partially surrounds the disk. The inner surface of the spray directing assembly is configured to change the trajectory of any liquid leaving the outer edge of the disk.

Description

[Technical Field]

[0001] The present invention relates to a spray unit and to a vehicle equipped with such a spray unit. [Background technology]

[0002] The general background of this invention is the application of pesticides to crops. The spray liquid must be atomized. This is typically done using hydraulic nozzles. A more sophisticated approach is to use a rotating disk. When the vehicle spraying the pesticide is a drone or unmanned aerial vehicle (UAV), dedicated spraying technology must be carefully considered due to the added weight and energy requirements. Therefore, rotating disks have potential as atomization systems for drone applications because the energy requirements for generating the droplets are generally small and the other components are compatible with battery-powered drones.

[0003] However, rotating disks are characterized by a horizontal spray sheet emerging within the plane of the disk, necessitating a method for directing the spray sheet toward the target crop. This can be achieved by tilting the disk sideways or by adding a shield to block unwanted spray. However, this adds complexity to designing a device to recover and reuse the blocked spray (see Micron Herbiflex 4, http: / / www.microngroup.com / agricultural / herbiflex-4). Furthermore, the output from the rotating disk is significantly reduced, requiring an additional atomization unit to compensate.

[0004] In unmanned aerial vehicles (UAVs), this can be achieved by placing a rotating disk below the rotor so that the so-called downdraft effect (wind generated by the rotor) directs the spray sheet downward toward the target crop. Similar air assist for directing the spray sheet can also be applied to land-based vehicles, such as tractors and unmanned ground vehicle guided vehicles (UGVs), equipped with spray booms or individual atomizing units. However, the combination of a rotating disk and a rotor or similar air assist produces a cone-shaped spray pattern, which results in non-uniform deposition on the target crop as the spraying vehicle travels across the target field. The deposition is higher at the edges and lower in the center, resulting in an M-shaped deposition. Because the deposition must be uniform across the swath, there is a need for a rotating-disk atomizing device that can produce a spray sheet oriented so that the deposition is uniform across the entire operating width, regardless of the number of spray units mounted on the sprayer. Summary of the Invention

[0005] It would be advantageous to have an improved means for spraying liquids, such as those containing chemical and / or biological agriculturally active ingredients.

[0006] The object of the present invention is solved by the subject matter of the independent claims, further embodiments are incorporated in the dependent claims. It should be noted that the aspects and examples described below with respect to the present invention apply both to a spray unit and to a vehicle having one or more spray units.

[0007] In a first aspect, a spray unit is provided. The spray unit includes a shaft, a disk, a liquid applicator, and a spray directing assembly. The disk is configured to rotate about the shaft centered on the center of the disk. The liquid applicator is configured to apply liquid to a surface of the disk. The spray directing assembly partially surrounds the disk. An inner surface of the spray directing assembly is configured to change the trajectory of any liquid leaving the outer edge of the disk.

[0008] In other words, a spray unit with a rotating disk containing a specially shaped stationary hood orients the spray sheet into a fan shape instead of a hollow cone shape. The stationary hood surrounds the rotating disk in a configuration that can capture the atomized droplets from the rotating disk and direct them in the desired direction.

[0009] In this way, an appropriate application of active ingredient per plant per unit area of ​​land can be provided.

[0010] In one example, the spray directing assembly has a hemispherical shape with opposite depending sidewalls, an opening at the top region, and an opening at the bottom region.

[0011] In one example, the shaft extends vertically through a central location of the opening in the top region of the spray directing assembly.

[0012] In this way, the spray directing assembly can be optimally positioned relative to the spray shaft and relative to the rotating disc to maximize its effect on the trajectory of any liquid leaving the outer edge of the disc.

[0013] In one example, the diameter of the opening in the bottom region of the spray directing assembly is larger than the diameter of the opening in the top region of the spray directing assembly.

[0014] In one example, the edge of the disk is positioned proximate to an inner surface of the spray directing assembly and proximate to a top region of the spray directing assembly.

[0015] In this way, the spray directing assembly directly influences the trajectory of all liquid leaving the disk without potentially causing any adverse effects on, for example, droplet size structure or distribution.

[0016] In one example, the shortest distance between the edge of the disc and the inner surface of the spray directing assembly is between 100 microns and 1 mm.

[0017] In one example, the inner surface of the spray directing assembly adjacent the opening in the bottom region, where the liquid leaves the spray directing assembly, is disposed at an angle relative to the plane of the surface of the disk.

[0018] In this way, the rotating disc can be operated in a horizontal position, making optimal use of the effects of centrifugal force to atomize the liquid, yet the spray directing assembly can be used to direct the atomized liquid towards the target area and / or crop to be sprayed, which is typically positioned at an angle relative to the horizontal position of the rotating disc.

[0019] In one example, the inner surface of the spray directing assembly includes a plurality of walls, the direction of the plurality of walls extending in a plane substantially perpendicular to the side of the disk, and further, the plane(s) of the plurality of walls is substantially perpendicular to the plane formed by the surface of the disk.

[0020] In this manner, channels or grooves are formed as part of the spray directing assembly that aid in the targeted distribution of spray droplets.

[0021] In one example, the walls are radially arranged around the disc, and preferably are equally spaced from one another around the disc.

[0022] In one example, the spray directing assembly has a circular opening in the top region and an oval opening in the bottom region.

[0023] In other words, the oval shaped opening in the bottom region of the spray directing assembly aids in obtaining a flat, fan-shaped spray pattern.

[0024] In one example, the interior surface of the spray directing assembly has a low friction surface.

[0025] In this way, the individual droplets formed from the rotating disk roll on the inner surface of the spray directing assembly without significant adhesion.

[0026] In one example, the ratio between the diameter of the disc and the maximum diameter of the opening in the bottom region of the spray directing assembly is between 1:2 and 1:20.

[0027] In one example, the spray directing assembly is double-walled, with the space between the two walls of the spray directing assembly configured to direct air flow in the spray direction.

[0028] In other words, the air curtain in the fixed hood assists in transporting the spray sheet to the target area and / or crop and penetration into the leaf cover. This is particularly appropriate at small spray rates (e.g., less than 50 l / ha) where the low momentum of the spray droplets and the cloud reduce droplet penetration into the crop cover. Air curtains can also be used to mitigate potential problems with wind drift.

[0029] In a second aspect, there is provided a spraying vehicle comprising at least one spraying unit according to the first aspect.

[0030] In one example, a spraying vehicle includes a liquid tank, a spraying unit having a spray directing assembly configured to flow air in a spray direction, at least one actuator, a plurality of sensors, and a processing unit. The liquid tank is configured to contain a liquid. The at least one spraying unit is configured to spray the liquid. The at least one actuator is configured to control airflow through a space in the spray directing assembly in the spray direction. At least one sensor in the plurality of sensors is configured to measure a speed of the spraying vehicle relative to the ground. At least one sensor in the plurality of sensors is configured to measure an air movement direction relative to the spraying vehicle relative to a longitudinal axis of the spraying vehicle. At least one sensor in the plurality of sensors is configured to measure an air movement velocity relative to the spraying vehicle. The processing unit is configured to determine an air movement direction relative to a projection of the longitudinal axis onto the ground and an air movement velocity relative to the ground, the determination including utilizing the speed of the spraying vehicle, the air movement direction relative to the spraying vehicle relative to the longitudinal axis of the spraying vehicle, and the air movement velocity relative to the spraying vehicle. The processing unit is configured to control at least one actuator, and determining at least one command for controlling the at least one actuator includes utilizing the determined direction of air movement relative to a projection of the longitudinal axis onto the ground and the determined speed of air movement relative to the ground.

[0031] In other words, the air curtain is designed to adjust the air flow to accommodate varying wind conditions over the area to be sprayed, for example to mitigate potential drift.

[0032] Advantageously, any advantage provided by any of the above aspects applies equally to all other aspects, and vice versa.

[0033] The above aspects and examples will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0034] Exemplary embodiments are described below with reference to the following drawings: [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is a side view showing a schematic configuration of an example of a newly developed spray unit. [Figure 2] FIG. 2 illustrates an example of a spray unit according to FIG. 1 in another side view. [Figure 3] FIG. 3 illustrates in side view an example of a spray unit according to FIG. 1 having multiple walls on the inner surface of the spray directing assembly. [Figure 4] FIG. 4 illustrates in a bottom view an example of a spray unit according to FIG. 3 having multiple walls on the inner surface of the spray directing assembly. [Figure 5] FIG. 5 illustrates an example of a spray unit according to FIG. 1 in a bottom view. [Figure 6] FIG. 6 illustrates an example of a spray unit according to FIG. 1 with an air flow path within the spray directing assembly. [Figure 7] FIG. 7 shows an example of a spray unit according to FIG. 1 with a cone-shaped disc. [Figure 8] FIG. 8 illustrates a schematic example of a spray vehicle including a spray unit. [Figure 9] FIG. 9 shows a schematic example of a spray vehicle with different spray units each with a corresponding spray swath. [Figure 10] FIG. 10 illustrates a schematic example of a spray vehicle having a spray unit and a control element for airflow through the spray directing assembly. [Figure 11A]FIG. 11A illustrates a schematic example of a spray vehicle with a spray unit and a control element for the airflow through the spray directing assembly as a function of different wind conditions. [Figure 11B] FIG. 11B illustrates a schematic example of a spray vehicle with a spray unit and a control element for the airflow through the spray directing assembly as a function of different wind conditions. DETAILED DESCRIPTION OF THE INVENTION

[0036] FIG. 1 illustrates an example spray unit 10 in side view. The spray unit includes a shaft 20, a disk 30, a liquid applicator 40, and a spray directing assembly 50. The disk is configured to rotate about the shaft centered on the center of the disk. The liquid applicator is configured to apply liquid to a surface of the disk. The spray directing assembly partially surrounds the disk. An inner surface 51 of the spray directing assembly is configured to change the trajectory of any liquid leaving the outer edge of the disk.

[0037] In this way, the spray directing assembly of the spray unit directs the spray sheet into a fan shape instead of a hollow cone shape. The fixed hood surrounds the rotating disk in a configuration that can capture and direct the atomized droplets from the rotating disk in the desired direction. As a result, it is easier to provide an appropriate application of active ingredient per unit area of ​​land per plant.

[0038] In one example, the term "disc" refers to a flat disc, but also includes a cone-shaped disc.

[0039] In one example, the disc includes a plurality of sets of teeth or sawtooth within the periphery of the disc.

[0040] In one example, the term "partially surrounding" refers to the spray directing assembly having a design and shape that alters the trajectory of at least all of the liquid that leaves the outer edge of the disk, however, the spray directing assembly only partially surrounds the disk due to the presence of an opening in the spray directing assembly.

[0041] In one example, the spray directing assembly does not rotate about an axis centered on the center of the disk, in other words, the spray assembly is in a fixed position relative to a disk that is configured to rotate about an axis centered on the center of the disk.

[0042] In one example, the liquid applicator includes at least one supply pipe configured to transport liquid from a liquid reservoir to the disk and to supply the liquid onto the disk.

[0043] In one example, the liquid applicator includes at least one liquid tank and at least one supply pipe.

[0044] In one example, the spray directing assembly has an exterior surface (54).

[0045] In one example, the term "liquid(s)" refers to one or more liquids containing chemical-based and / or biological-based agriculturally active ingredients, such as, for example, herbicides, insecticides, fungicides, crop nutrients, biostimulants, plant growth regulators, etc.

[0046] In one example, an arrow near the shaft indicates a potential direction of rotation for the shaft and disc. The rotation can also be clockwise.

[0047] In one example, arrows on the plane of the disc represent directions for centrifugal force and atomization of the liquid.

[0048] According to one example, the spray directing assembly has a hemispherical shape with opposite depending side walls, an opening 52 in a top region, and an opening 53 in a bottom region.

[0049] The term "hemisphere" is intended to include shapes other than true spheres, illustratively including hemispherical shapes, or semi-ellipsoidal shapes, such as semi-spheroidal or semi-ellipsoidal shapes. For example, a shape may include multiple surfaces with different degrees of rounding. In such embodiments, small discontinuities may exist where two or more such surfaces join.

[0050] In one example, the spray directing assembly has a hemispherical shape.

[0051] In one example, the terms "top region" and "bottom region" refer to geographic locations relative to the ground, with the "bottom region" being closer to the ground than the "top region."

[0052] According to one example, the shaft extends vertically through a central location of the opening in the top region of the spray directing assembly.

[0053] In one example, the supply pipe of the liquid applicator extends through an opening in the top region of the spray directing assembly.

[0054] According to one example, the diameter of the opening at the bottom region of the spray directing assembly is larger than the diameter of the opening at the top region of the spray directing assembly.

[0055] In one example, the openings in the bottom region have a cross-section that is circular or elliptical, and the spray swath of atomized liquid leaving the openings in the bottom region toward the target crop and / or toward the target region has the same or a similar cross-section (and therefore is also circular or elliptical) as the openings in the bottom region.

[0056] According to one example, the edge of the disk is positioned proximate to an inner surface of the spray directing assembly and proximate to a top region of the spray directing assembly.

[0057] In one example, the ratio of the distance between the disc and the opening in the top region of the spray directing assembly to the distance between the disc and the opening in the bottom region of the spray directing assembly is 1:2 to 1:20, preferably 1:3:1:10.

[0058] According to one example, the shortest distance between the edge of the disc and the inner surface of the spray directing assembly is between 100 microns and 1 mm, more preferably between 150 microns and 500 microns.

[0059] According to one example, the inner surface of the spray directing assembly adjacent the opening in the bottom region, where the liquid leaves the spray directing assembly, is disposed at an angle relative to the plane of the surface of the disk.

[0060] In other words, the liquid leaving the disk impinges on the inner surface of the spray directing assembly. At the opening in the bottom region, the atomized liquid leaves the spray directing assembly after tilting the inner surface of the spray directing assembly downward. The direction of the atomized liquid is controlled by the spatial design of the inner surface at the bottom of the spray directing assembly. The departure direction of the atomized liquid toward the target crop and / or toward the target area is arranged at an angle relative to the plane of the disk surface.

[0061] In one example, the spray directing assembly is oriented at a substantially perpendicular angle relative to the plane of the surface of the disk, where the term "substantially perpendicular" in this context refers to 90°±50°, preferably 90°±30°, more preferably 90°±20°, and most preferably 90°±10°.

[0062] As an example, the arrow adjacent to the atomized liquid leaving the spray directing assembly in FIG. 1 represents one possible direction of the leaving atomized liquid relative to the horizontal surface of the disk.

[0063] In one example, an arrow near the shaft indicates a possible direction of rotation about the shaft, which can also be clockwise.

[0064] In one example, an arrow above the disk represents the direction of the disk's centrifugal force and the direction of liquid atomization.

[0065] It should be noted that "atomization" does not mean individual atoms, but rather, in reference to the standard use of this term in relation to spray systems, means a fine mist of particles that may range in size.

[0066] Figure 2 illustrates another side view of the example spray unit 10 according to Figure 1. The spray directing assembly 50 partially surrounds the disk 30 and has an opening 52 in its top region for the shaft 20 and liquid applicator 40. The spray directing assembly 50 also has an opening 53 in its bottom region through which the atomized liquid leaves the spray unit. The arrow in Figure 2 near the shaft indicates a possible rotation direction for the shaft. The rotation can also be clockwise.

[0067] 3 illustrates an example of the spray unit 10 according to FIG. 1 having a plurality of walls 70 on the inner surface of the spray directing assembly 50. The inner surface 51 (numbering not shown in the figure) of the spray directing assembly includes a plurality of walls, the direction of the plurality of walls extending in a plane substantially perpendicular to the side of the disk, and the plane of the plurality of walls is substantially perpendicular to the plane of the surface of the disk 30.

[0068] In one example, in this context, the term "substantially perpendicular" to the side of the disc refers to an angle of 90°±40°, preferably 90°±30°, and more preferably 90°±20°.

[0069] In one example, the term "substantially perpendicular" of the plane(s) of the walls to the plane of the surface of the disk refers to an angle of 90°±30°, preferably an angle of 90°±20°, and more preferably an angle of 90°±10°.

[0070] According to one example, the walls are radially (circumferentially) arranged around the disc, and preferably are equally spaced from one another around the disc.

[0071] The arrows in Figure 3 indicate the possible directions of rotation about the shaft. The rotation can also be clockwise.

[0072] 4 illustrates, in a bottom view, an example of the spray unit 10 according to FIG. 3 having multiple walls 70 on the inner surface of the spray directing assembly 50. The disk 30 is shown from the bottom through an opening 53 (number not shown in the figure). The disk is partially surrounded by the spray directing assembly. The inner surface 51 of the spray directing assembly includes multiple walls that extend in a plane substantially perpendicular to the side of the disk, and the plane of the multiple walls is substantially perpendicular to the plane of the surface of the disk.

[0073] In one example, the planar surface of the disk refers to the circular portion where liquid from the liquid applicator impinges on the disk, where the liquid is atomized by the centrifugal force of the rotating disk, and where the atomized liquid ultimately leaves the disk at the periphery of the planar surface.

[0074] In one example, the arrows represent potential rotation directions for a rotating disk, which can also be clockwise.

[0075] Figure 5 illustrates an example of a spray unit 10 according to Figure 1 in a bottom view. The disk 30 (dotted line) is shown from the bottom side through an opening 53. The disk is partially surrounded by a spray directing assembly 50. The spray directing assembly has a circular opening 52 in the top region and an oval-shaped opening 53 in the bottom region.

[0076] In one example, the arrows represent potential rotation directions for a rotating disk, which can also be clockwise.

[0077] According to one example, the inner surface 51 of the spray directing assembly 50 has a low friction surface.

[0078] In one example, the inner surface of the spray directing assembly is hydrophobic.

[0079] The surface chemistry of the inner surface can be modified. In the case of smooth surfaces, the surface adhesion of the sprayed liquid (either as a film, ligaments, or droplets) can be modified in this way. In the case of aqueous liquids, hydrophilic surfaces will be less slippery and have greater adhesive forces, while hydrophobic surfaces will be more slippery and have less adhesive forces (and vice versa for oils). However, in the case of smooth surfaces, the range of accessible adhesive forces is not large (as evidenced by the narrow range of contact angles).

[0080] In one example, the inner surface of the spray directing assembly is textured.

[0081] The inner surface may, for example, include a comb-like structure. As an example, 3D printing may be used to create textured surface structures.

[0082] In one example, the size of the texture feature is between 10 nm and 100 microns, preferably between 1 micron and 80 microns.

[0083] In the case of microtextured surfaces, the range of adhesion forces (and contact angles) is significantly increased (further details are given in the paper by Bico et al., Wetting of textured surfaces, Colloids and Surfaces A 206 (2002) 41-16).

[0084] In one example, the inner surface of the spray directing assembly has a contact angle with water of greater than 110°, preferably greater than 120°.

[0085] In one example, the inner surface of the spray directing assembly is superhydrophobic, preferably having a contact angle with water of greater than 150°.

[0086] Those skilled in the art know that the larger the angle, the lower the adhesion force.

[0087] In one example, the interior surface of the spray directing assembly is configured to emit an air cushion that prevents droplets from contacting the interior surface.

[0088] Recent advances in wetting textured surfaces have resulted in surfaces that are non-wetting for a wide range of liquids. (Further details are provided in A Tuteja et al, Robust omniphobic surfaces, PNAS 105 (2008) 18200-18205; U.S. Patent Application Publication Nos. 2019 / 0077968(A1); 2019 / 0039796(A1); 2015 / 0273518(A1); https: / / en.wikipedia.org / wiki / LiquiGlide.) Such surfaces can also be used for the interior surfaces of spray directing assemblies.

[0089] According to one example, the ratio between the diameter of the disc 30 and the maximum diameter of the opening 53 in the bottom region of the spray directing assembly 50 is between 1:2 and 1:20, preferably between 1:4 and 1:10.

[0090] Figure 6 illustrates an example of a spray unit 10 according to Figure 1 with an air flow path in the spray directing assembly. The spray unit 10 is similar to the spray unit described in Figure 1, except that the spray directing assembly is double-walled. A space 60 between the two walls of the spray directing assembly is configured to direct air flow in the spray direction.

[0091] In one example, the space 60 between the two walls is also referred to as one (or more) "air flow passages."

[0092] In one example, the airflow is driven by a fan and flows through space 60 from the top to the bottom region of the spray directing assembly.

[0093] In one example, the fan may be a propeller, such as on a UAV. Downward airflow from the propeller is directed through space 60 to a bottom region of the spray directing assembly. For example, an actuator controls the volumetric airflow per unit time through space 60.

[0094] It should be noted that the air volume flow rate per unit time can be calculated for an air flow path by multiplying the air flow velocity by the space cross-sectional area for a particular unit of time.

[0095] In one example, the interior surface of the spray directing assembly preferably includes substantially uniformly distributed voids that allow air to flow toward the interior surface and create an air cushion that prevents droplets leaving the disk from contacting the interior surface.

[0096] In one example, the arrows shown in FIG. 6 have similar meanings as those described in the context of FIG. 1, except that the arrow near space 60 represents the flow direction of the airflow from the top region of the spray directing assembly to the bottom region and further toward the spray direction.

[0097] 7 illustrates an example of the spray unit 10 according to FIG. 1 having a cone-shaped disc 30. The spray unit 10 includes a shaft 20, a cone-shaped disc 30, a liquid applicator 40, and a spray directing assembly 50.

[0098] In one example, the arrows shown in FIG. 7 have the same meaning as those described in the context of FIG.

[0099] In one example, the spraying unit may be used on boom sprayers, unmanned aerial vehicles (UAVs), unmanned ground vehicles (UGVs), robotic platforms, and backpack sprayers.

[0100] FIG. 8 shows a schematic example of a spraying vehicle 100 having the spraying unit 10 described with reference to FIG.

[0101] In one example, the vehicle is a drone or UAV.

[0102] In one example, the vehicle is a land vehicle, such as an unmanned ground vehicle (UGV), a robotic platform, a tractor, or the like.

[0103] FIG. 9 illustrates a schematic example of a spray vehicle with different spray units and corresponding spray swaths. In example a), the spray vehicle includes a spray unit with a rotating disk 30 but no spray directing assembly. The resulting spray swath, shown on the right, has an M-shape with a large distance across the spray swath. In example b), the spray vehicle includes a rotating disk 30 and a spray directing assembly 50 with a circular opening 53 in its bottom region. A more uniform spray swath is obtained when sprayed by such a spray vehicle compared to the spray swath shown in example a). In example c), the spray vehicle includes a rotating disk 30 and a spray directing assembly 50 with an oval opening 53 in its bottom region and multiple walls 70 on its inner surface. The spray swath is uniform across the entire spray swath distance. The arrows on the disk 30 in examples a) to c) indicate the direction of disk rotation, which may also be clockwise.

[0104] FIG. 10 illustrates a schematic example of a spray vehicle 100 including a liquid tank 110, a spray directing assembly 50 having a space (air flow path) 60 configured to direct air in a spray direction, at least one actuator 120, a plurality of sensors 130, and a processing unit 140. The liquid tank is configured to contain a liquid. The at least one spray unit is configured to spray the liquid. The at least one actuator is configured to control airflow through the space 60 of the spray directing assembly in a spray direction. At least one sensor 131 of the plurality of sensors is configured to measure the speed of the spray vehicle relative to the ground. At least one sensor 132 of the plurality of sensors is configured to measure the direction of air movement relative to the spray vehicle with respect to the longitudinal axis of the spray vehicle. At least one sensor 133 of the plurality of sensors is configured to measure the speed of air movement relative to the spray vehicle. The processing unit is configured to determine an air movement direction relative to a projection of the longitudinal axis on the ground and to determine an air movement speed relative to the ground, the determining including utilizing a speed of the spraying vehicle, an air movement direction relative to the spraying vehicle with respect to the longitudinal axis of the spraying vehicle, and an air movement speed relative to the spraying vehicle. The processing unit is configured to control at least one actuator, and the determining of at least one command for controlling the at least one actuator includes utilizing the determined air movement direction relative to the projection of the longitudinal axis on the ground and the determined air movement speed relative to the ground.

[0105] In one example, the at least one sensor 131 configured to measure the speed of the spray vehicle relative to the ground includes a GPS system.

[0106] In one example, the at least one sensor 131 configured to measure the speed of the spraying vehicle relative to the ground includes a laser reflectance-based system.

[0107] In one example, the at least one sensor 132 configured to measure the direction of air movement relative to the spraying vehicle includes a wind vane.

[0108] In one example, the at least one sensor 133 configured to measure air movement speed relative to the spraying vehicle includes an anemometer.

[0109] In one example, the at least one sensor 133 configured to measure air movement velocity relative to the spraying vehicle includes a Pitot tube.

[0110] In one example, at least one sensor 132 and 133 configured to measure air movement direction, speed (and distance) relative to the spraying vehicle includes a LIDAR sensor, preferably a Doppler LIDAR sensor.

[0111] In one example, "at least one actuator" refers to at least one mechanical device that converts energy into movement. The energy source may be, for example, an electric current, hydraulic fluid pressure, air pressure, mechanical energy, thermal energy, or magnetic energy. For example, an electric motor assembly may be a type of actuator that converts electric current into rotational movement and may further convert the rotational movement into linear movement to perform actuation. As such, an actuator may include a motor, gears, links, wheels, screws, pumps, pistons, switches, servos, or other components for converting some form of energy into movement.

[0112] In one example, "at least one actuator" refers to at least one mechanical device that controls airflow through space 60, where the volumetric airflow is generated by a propeller of the UAV.

[0113] 11A and 11B each illustrate a schematic example of a spray vehicle 100 having a spray unit 10 and a control element for controlling airflow through the spray directing assembly 50 as a function of different wind conditions. In this example, the spray vehicle is a UAV and includes at least one spray unit disposed below the UAV's propeller unit. The spray unit includes a spray directing assembly 50 configured to direct airflow in a spray direction, and the spray directing assembly has a space 60 between two walls of the spray directing assembly. Multiple sensors 130 sense, among other things, the direction and speed of air movement (wind). A processing unit (not shown) uses the sensed information to command at least one actuator (not shown) to control airflow through the space of the spray directing assembly in the spray direction. In the example of FIG. 11A, the wind has a low wind speed, so a small amount of airflow flows through the space of the spray directing assembly in the spray direction. In the example of FIG. 11B, the wind has a high wind speed, causing a large amount of airflow through the space of the spray directing assembly in the spray direction.

[0114] It should be noted that embodiments of the present invention are described with reference to different subject matters. In particular, some embodiments are described with reference to spray unit type claims, while other embodiments are described with reference to spray vehicle type claims. However, a person skilled in the art will infer from the above and following descriptions that, unless otherwise specified, any combination of features belonging to one type of subject matter, as well as any combination of features related to different subject matters, is considered to be disclosed by the present application. However, all features can be combined and can provide synergistic effects that exceed the mere sum of the features.

[0115] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the dependent claims.

[0116] In the claims, the word "comprising" does not exclude other elements or other steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting their scope.

Claims

1. A spray unit (10), comprising: - a shaft (20), a disk (30), a liquid applicator (40), a spray directing assembly (50), the disc is flat or conical in shape and is configured to rotate about the shaft centered on the center of the disc; the liquid applicator is configured to apply a liquid to a surface of the disc; The spray directing assembly partially surrounds the disc, and an inner surface of the spray directing assembly is configured to change the trajectory of any liquid that leaves the outer edge of the disc.

2. 2. The spray unit of claim 1, wherein the spray directing assembly has a hemispherical shape with opposite depending side walls, an opening (52) in a top region, and an opening (53) in a bottom region.

3. 3. The spray unit of claim 2, wherein the shaft extends vertically through a central location of the opening in the top region of the spray directing assembly.

4. 4. A spray unit according to claim 2 or 3, wherein the diameter of the opening at the bottom region of the spray directing assembly is greater than the diameter of the opening at the top region of the spray directing assembly.

5. A spray unit as described in any one of claims 1 to 4, wherein the edge of the disk is positioned in close proximity to the inner surface of the spray directing assembly and in close proximity to the top region of the spray directing assembly.

6. A spray unit according to any preceding claim, wherein the shortest distance between the edge of the disc and the inner surface of the spray directing assembly is between 100 microns and 1 mm.

7. A spray unit as described in any one of claims 1 to 6, wherein the inner surface adjacent to the opening in the bottom region of the spray directing assembly, from which liquid leaves the spray directing assembly, is positioned at an angle relative to the plane of the surface of the disk.

8. A spray unit as described in any one of claims 1 to 7, wherein the inner surface of the spray directing assembly includes a plurality of walls (70), the direction of the plurality of walls extending in a plane substantially perpendicular to the side of the disc, and further, the plurality of walls are substantially perpendicular to the plane defined by the surface of the disc.

9. 9. A spray unit according to claim 8, wherein the walls are arranged radially around the disc, and preferably equally spaced from one another around the disc.

10. A spray unit according to any one of the preceding claims, wherein the spray directing assembly has a circular opening in the top region and an oval opening in the bottom region.

11. A spray unit according to any preceding claim, wherein the inner surface of the spray directing assembly has a low friction surface.

12. A spray unit according to any one of the preceding claims, wherein the ratio between the diameter of the disc and the maximum diameter of the opening in the bottom region of the spray directing assembly is between 1:2 and 1:

20.

13. 13. A spray unit according to any one of claims 1 to 12, wherein the spray directing assembly is double-walled and the space (60) between the two walls of the spray directing assembly is configured to direct air flow in the spray direction.

14. A spraying vehicle (100) comprising at least one spraying unit (10) according to any one of claims 1 to 13.

15. a liquid tank (110), at least one actuator (120); a plurality of sensors (130); a processing unit (140), The liquid tank is configured to contain a liquid; the at least one spray unit is configured to spray a liquid; the at least one actuator is configured to control airflow through the space (60) of the spray directing assembly in a spray direction; At least one sensor (131) in the plurality of sensors is configured to measure the speed of the spray vehicle relative to the ground; At least one sensor (132) in the plurality of sensors is configured to measure a direction of air movement relative to the spraying vehicle with respect to a longitudinal axis of the spraying vehicle; At least one sensor (133) in the plurality of sensors is configured to measure air movement velocity relative to the spraying vehicle; the processing unit is configured to determine an air movement direction relative to a projection of the longitudinal axis onto the ground and to determine an air movement speed relative to the ground, the determination including utilizing the speed of the spraying vehicle, the air movement direction relative to the spraying vehicle with respect to the longitudinal axis of the spraying vehicle, and the air movement speed relative to the spraying vehicle; The spray vehicle (100) of claim 14, wherein the processing unit is configured to control the at least one actuator, and determining at least one command for controlling the at least one actuator includes utilizing the determined direction of air movement relative to a projection of the longitudinal axis onto the ground and the determined speed of air movement relative to the ground.

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