Distribution system and method for applying spray liquids for an agricultural field sprayer

Abstract

Distribution system (12) for an agricultural field sprayer (10) for applying spray liquids, with at least one reservoir (22) for providing the respective spray liquid, wherein the spray liquid is conveyed from the reservoir (22) along a liquid line (32) guided on a spray boom mounted on the field sprayer (10) by means of a pump (36) with variably variable pressure and / or by means of pressure regulated to a constant value, thereby supplying spray nozzles (34) with spray liquid, wherein a switching element (38) controlled by means of a variably variable pulse width modulation is assigned to or arranged downstream of the liquid line (32), and in that at least two spray nozzles (34) spaced apart from each other and in fluid communication with it are arranged downstream of the switching element (38), characterized in thatthat the pulse width modulation is varied depending on the lengths of the fluid lines (32) and / or depending on the cross-sectional areas of the fluid lines (32).

Description

[0001] The present invention relates to a distribution system for applying spray liquids for an agricultural field sprayer with the features of independent claim 1. The invention further relates to a method for applying spray liquids with the features of method claim 19.

[0002] Field sprayers are used to distribute liquid and / or solid agricultural pesticides or spray solutions. Each of these field sprayers is equipped with a distribution system to ensure the most precise possible application of the respective spray solution. The spray solution is distributed over a crop or field using a variety of spray nozzles. These nozzles are typically mounted on a nozzle assembly, which can contain one, two, or more nozzles. These nozzles can also have different properties, meaning they can produce different droplet spectra.

[0003] To achieve varying application rates with a single spray nozzle at constant pressure and with a consistent droplet spectrum, systems and spray nozzles are known that are controlled using pulse width modulation (PWM). Each spray nozzle is assigned a valve that switches at a frequency of, for example, 10 Hz (Hertz). This means that the nozzle opens and closes 10 times per second. The valves also have a variable duty cycle, for example, 80%. Based on the frequency and the respective duty cycle, the flow rate of spray fluid through the nozzle can be varied. To further improve this, systems are also known in which the frequency has been increased even further, to, for example, 25 Hz or 50 Hz.

[0004] Such a system, or rather such control of spray nozzles using pulse width modulation, has already been introduced, for example, by the "DynaJet Flex 7120" nozzle control system from the company "TeeJet Technologies". By rapidly opening and closing the nozzle (i.e., by using a correspondingly high frequency) and by adjusting the duty cycle (i.e., by adjusting the opening times), large ranges in the application rate can be achieved with the same spray nozzle.

[0005] A disadvantage of the system known from the prior art is that each spray nozzle requires a separate valve for generating the pulse frequency or pulse width modulation. For example, with a nozzle spacing of 25 cm and a sprayer working width of 30 meters, up to 120 nozzles, each with its own separate valve, are needed.

[0006] If the field sprayer is to be capable of producing further application patterns and droplet spectra, then, for example, two, four, or more spray nozzles can be mounted on a single nozzle assembly. Each of these spray nozzles can, in turn, be assigned a valve for pulse width modulation. Such a design can result in several hundred valves being installed on the field sprayer. These valves are expensive and also require costly controls, wiring, and the like. Costs of up to €900 per meter of working width are therefore quite possible, meaning that the use of such pulse width modulation valves is not recouped solely through savings in pesticides.

[0007] The valves can also be damaged, especially if they come into contact with the respective pesticide or spray solution. This, in turn, can negatively affect the performance of the spray nozzles.

[0008] The aim of the present invention is therefore to provide a distribution system for an agricultural field sprayer for the application of spray liquid, in which the advantages brought about by pulse width modulation in the application of plant protection products are present, but to achieve this with a minimum reduced number of switching elements for generating pulse width modulation without negatively affecting the distribution quality.

[0009] These tasks are solved by a distribution system for applying spray liquids, which is used in particular in agricultural field sprayers, with the features of independent claim 1, and by a method for applying spray liquids with the features of independent claim 19. Advantageous further developments are specified in the dependent claims and the description.

[0010] To solve the aforementioned problems, the invention proposes a distribution system, which is particularly suitable for use on an agricultural distribution machine or similar.

[0011] The field sprayer is used. The field sprayer includes at least one reservoir for supplying the respective spraying fluid, whereby the spraying fluid is pumped from the reservoir along a fluid line attached to a spray boom mounted on the field sprayer by means of a pump with variably adjustable and / or constantly regulated pressure. This supplies spray nozzles attached to the spray boom with spraying fluid.

[0012] In order to provide a distribution system for an agricultural field sprayer for the application of spray liquid, in which the advantages brought about by pulse width modulation in the application of plant protection products are present, but this is achieved with a minimal number of switching elements for generating pulse width modulation without negatively affecting the distribution quality, it is provided that a switching element controlled by means of a variably variable pulse width modulation is assigned to or downstream of the liquid line, and that two spray nozzles spaced apart from each other and in fluid communication with the switching element are downstream of it.In particular, the distribution system according to the invention makes it possible to cover a significantly larger working width with just one switching element with pulse width modulation compared to systems known from the prior art.

[0013] If the switching element, controlled by a variable pulse width modulation, is located within the liquid line, the volume flow along the liquid line can be directly regulated or influenced by the switching element. If the switching element, controlled by a variable pulse width modulation, is located downstream of the liquid line, the volume flow branched off or divided from the liquid line can be regulated or influenced by the switching element, whereby the volume flow along the liquid line can remain largely unaffected by this regulation.

[0014] It should first be noted that pulse width modulation, or a switching element controllable with variable pulse width modulation, refers in particular to switching elements that can be controlled by pulse width modulation (PWM), pulse duration modulation, pulse length modulation, subharmonic modulation, or pulse width modulation. All these control methods are subsequently grouped under the term pulse width modulation or PWM.

[0015] In particular, the pulse-width modulated switching element can be a valve, such as a solenoid valve. It can also be a motor-driven element, such as a stepper motor or similar motorized element. Various actuators, such as cylinders, are also conceivable as switching elements. The switching element is designed in such a way that the respective fluid delivery or volume flow in the distribution system and / or in the spray nozzles can be controlled within defined or definable pulse widths. For this purpose, the switching element can be controlled accordingly by a control and / or regulation device.

[0016] The switching element can be controlled by a control and / or regulating device at a fixed or variable frequency. This frequency can be greater than or equal to 10 Hz, 50 Hz, or 200 Hz. Alternatively, the frequency can be an optimization parameter stored in the control and / or regulating device, which may be defined depending on the specific components of the distribution system. In particular, the frequency can be increased or decreased depending on the individual spray nozzles.

[0017] Pulse width modulation is further defined by a duty cycle. This duty cycle is determined by the ratio between the pulse duration t (time period) and the period T (oscillation period). The pulse duration t can also be referred to as the on-time, i.e., the time during which the switching element is switched on, preferably in the open position.

[0018] The duty cycle is also specified as a percentage (%). The duty cycle is thus defined by t / T. This means that if the ratio t = 0, the switching element is permanently fully closed. Conversely, if the ratio t = T, the switching element is permanently fully open.

[0019] According to the invention, it can be provided that 0 < t / T < 1, whereby the switching element is intermittently opened and closed. The application rate of spray liquid can be decreased or increased by varying the duty cycle, i.e., by varying the ratio t / T. In particular, an increase in the application rate is achieved by increasing the duty cycle, especially by increasing the pulse duration t, and a decrease in the application rate is achieved by decreasing the duty cycle, especially by decreasing the pulse duration t.

[0020] To vary the output quantity or the duty cycle, both the pulse duration t and the period T could be varied using pulse width modulation controlling the switching element. This could be achieved using a control program stored in a control and / or monitoring device. Alternatively, the duty cycle could be varied manually by an operator.

[0021] For example, if the duty cycle is 80% and the frequency is 1 Hz, this means that, based on a frequency of 1 Hz (i.e., 1 second), the switching element is theoretically open for 0.8 seconds and closed for 0.2 seconds. However, since switching elements and their associated spray nozzles typically exhibit inertia, they are generally not completely closed due to the high frequencies. Instead, depending on the frequency and duty cycle, they only close to a corresponding intermediate position between the fully open and fully closed positions. In terms of the spray fluid flow rate, this means that an average value is established between the fully open and fully closed positions of the switching element. Consequently, the spray fluid application rate also adjusts to this intermediate value, which in turn means that the flow rate...The amount of spray fluid dispensed is generally reduced compared to an open switching element.

[0022] Depending on the respective duty cycle and / or frequency, the application rate can therefore be increased or decreased or at least kept largely constant, whereby as a rule the higher the duty cycle, the higher the application rate.

[0023] Furthermore, the lower the frequency, the greater the time required to close the switching element; conversely, the higher the frequency, the shorter the time required to close the switching element, and the greater the resulting average value, and consequently the greater the output quantity.

[0024] Pulse width modulation (PWM) is used to control the switching element with a square wave signal. Due to the inertia of the switching element or spray nozzle, particularly at its closing or opening mechanism, this square wave signal generates a sinusoidal oscillation and / or a triangle wave and / or a sawtooth wave. The type of resulting signal depends on the inertia of the switching element and the frequency.

[0025] A field sprayer used for applying spraying liquid can be either self-propelled or towed by a vehicle. It can also be mounted on a towing and / or transport vehicle, particularly a tractor. Finally, a field sprayer could be an autonomous vehicle.

[0026] Using field sprayers according to the invention, or field sprayers to which the distribution system according to the invention is attached, plant protection products or sprays are distributed over an agricultural field. The plant protection product can be, in particular, a liquid mixed with a carrier liquid (preferably water) and / or granules dissolved in a carrier liquid. The mixtures thus produced can be referred to as spray liquids. Various granules and / or liquids can also be mixed with a carrier liquid to form a spray liquid. Examples of plant protection products include pesticides, herbicides, fungicides, insecticides, and similar substances. Various fertilizers can also be used as plant protection products.

[0027] For carrying and supplying the respective plant protection products or spray solutions, a storage container is assigned to or functionally connected with the field sprayer, or the distribution system includes a corresponding storage container for carrying and supplying the respective spray solution. Two or more storage containers may also be provided, allowing for the transport of different plant protection products or spray solutions, and these storage containers may have different volumes.

[0028] A spray boom is attached to the field sprayer, preferably at its rear. The height of the spray boom can be adjusted by means of actuators, relative to the crop or the frame supporting the sprayer's components. In a working position, the spray boom extends across a wide working width of, for example, 12 meters, 18 meters, 30 meters, or more, perpendicular to the sprayer's direction of travel. The spray boom can also consist of two, three, or more segments. These segments can be pivoted relative to each other around their vertical axis. Furthermore, the spray boom, or its segments, can be pivoted relative to each other around their vertical axes in such a way that a legally required transport width of, for example, 3 meters for road transport is not exceeded.

[0029] To distribute the spray solution, multiple spray nozzles are arranged at intervals along the spray boom. Each nozzle atomizes the spray solution, creating a specific droplet spectrum. This spectrum then determines how the treated field and its plants are covered and wetted with the spray solution.

[0030] In a further development of the invention, the spray nozzles can be mounted on so-called nozzle assemblies. These nozzle assemblies are, in turn, spaced apart from one another on the spray boom. The nozzle assemblies can be single, double, or multiple, meaning that one, two, or more spray nozzles can be mounted on each assembly. In the case of a double or multiple nozzle assembly, spray nozzles with different properties can also be mounted, i.e., nozzles that produce different droplet spectra. It can also be provided that only one of the spray nozzles mounted on a double or multiple nozzle assembly distributes the spraying liquid at any given time, whereby the spray nozzles can be switched on or off automatically, for example, by means of a valve, or manually by an operator.

[0031] Examples of spray nozzles that can be used include injector nozzles, band spray nozzles, flat jet nozzles, double flat jet nozzles, high-pressure nozzles, and similar types. Furthermore, trailing hoses can be attached to at least some of the spray nozzles.

[0032] The at least two spray nozzles and / or nozzle assemblies downstream of the switching element can be mounted at a minimum distance of 10 cm from each other. Specifically, the spray nozzles and / or nozzle assemblies are mounted at distances of 25 cm, 50 cm, and / or 100 cm from each other. Other distances are also possible. In the case of a multi-nozzle assembly, these distances can be measured from its center point. Furthermore, the distances are measured perpendicular to the direction of travel, or in the direction of extension of the spray boom.

[0033] To supply the nozzle bodies or spray nozzles with spray fluid, they are connected to at least one fluid line carrying the spray fluid. The fluid line is also connected to the reservoir.

[0034] The fluid line can also consist of several sections. These sections connect the components of the distribution system. Branches for nozzle holders and / or spray nozzles, for example, can also be installed between the sections.

[0035] In a further training system, the fluid line, together with the reservoir and pump, can form a fluid circuit. This allows the fluid to be pumped from the reservoir to the spray boom or to the associated spray nozzles and / or nozzle holders via the fluid line, and then back to the reservoir. The fluid line can thus form a ring main, within which the spray fluid continuously circulates. This has the advantage that each spray nozzle and / or nozzle holder is supplied with sufficient spray fluid, which is then applied by opening the nozzles and / or nozzle holders. Any unused spray fluid is returned to the reservoir or recirculated.The resulting fluid cycle causes the spray fluid to circulate continuously within the distribution system.

[0036] The distribution system can also provide several such fluid circuits, so that, for example, each section of the spreader has a separate fluid circuit. The two or more fluid circuits can share a common reservoir and a common pump, or they can each have a separate reservoir and / or a separate pump.

[0037] It would also be conceivable that each spray nozzle and / or nozzle assembly is connected to two or more such liquid lines or liquid circuits in order to be able to apply different spray liquids, for example.

[0038] The spray fluid is pumped along the fluid line at variable and / or constant pressure. To adjust the application rate, the fluid line and the fluid circuit are equipped with at least one control valve to vary the flow rate of the spray fluid. This control valve can be, for example, a two-way valve, a flow regulator, or a similar type of valve.

[0039] The pump can be, for example, a centrifugal pump, a piston diaphragm pump, or a similar type. It can also be hydraulically, electrically, and / or pneumatically driven. Furthermore, the pump can regulate the required flow rate, for example, by means of an associated proportional valve. The pump can also be controlled by a control device to generate a defined or variable pressure in the fluid line or distribution system. This control can be automated or manual.

[0040] It can be specifically designed that the pressure remains constant depending on the spray nozzles used and the pulse width modulation, meaning that it is regulated to a largely constant pressure in the liquid line or distribution system. This constant regulation can also allow deviations of, for example, 0.1 bar or 0.2 bar or more.

[0041] The pressure in the liquid line can be varied, for example, by means of the pump, and can be greater than or equal to 0.5 bar and less than or equal to 20 bar, but in particular less than or equal to 10 bar.

[0042] Furthermore, appropriate sensors or monitoring devices can be used to monitor the pressure in the liquid line or distribution system. In particular, this pressure can serve as a control variable for a control program stored in the control unit. Pressure sensors, for example, can be used as sensors or monitoring devices for this purpose.

[0043] To achieve an even more precise reduction or adjustment of the application rate, it can also be provided that the respective pressure in the liquid line is varied according to the pulse width modulation or the duty cycle of the switching element.

[0044] In one embodiment, it can be provided that a switching element controlled by means of a variably variable pulse width modulation is assigned to the liquid line and / or the liquid circuit, i.e. a switching element can be integrated into the liquid line and / or a switching element can be operatively connected to the liquid line in such a way that a pulse width modulation generated by the switching element is transmitted accordingly to the liquid flow through the liquid line or also the liquid circuit.

[0045] In another embodiment, a switching element controlled by a variably variable pulse width modulation can be located downstream of the liquid line. This means, for example, that a branch can be installed in the liquid line, to which a connecting element and / or a nozzle assembly is attached. Thus, the branch, connecting element, and / or nozzle assembly, each located downstream of the liquid line, could also be assigned a switching element or be operatively connected to them in such a way that a pulse width modulation generated by the switching element is transmitted to the liquid flow through the branch, connecting element, and / or nozzle assembly.

[0046] In order to reduce the number of switching elements to a minimum, the invention provides for covering the largest possible working width of the field sprayer with only one switching element, whereby this is achieved according to the invention by having at least two spray nozzles spaced apart from each other arranged downstream of the switching element, which spray nozzles are also in fluid connection with the switching element or with the liquid line whose liquid flow is changed by the switching element and / or the branch and / or the connecting element and / or the nozzle assembly, so that the pulse width modulation acting on them is transmitted to the at least two subsequent spray nozzles.

[0047] At least two spray nozzles can be arranged downstream of the switching element, spaced apart from each other, with a distance of at least 10 cm or more. Preferably, this distance is 25 cm and / or 50 cm and / or 100 cm. Other distances are also conceivable.

[0048] It should be noted that the switching element can in turn be followed by two nozzle manifolds, on each of which at least one spray nozzle is attached, whereby, due to the distance between the nozzle manifolds, at least two spray nozzles spaced apart from each other are again followed by the switching element.

[0049] In a further development of the invention, the distance between the at least two spray nozzles is defined in such a way that the droplet spectra generated by them do not negatively influence each other.

[0050] With such a design or with a distribution system according to the invention, the pulse width modulation generated by means of a switching element is not transmitted, as is known from the prior art, only to one spray nozzle and thus to a very small working width of the spray boom, but to a plurality of spray nozzles and thus to a correspondingly larger working width of the spray boom.

[0051] Further training may include the sensor-based detection of the droplet spectrum generated by the spray nozzles and / or the wetting of the plants caused by the spray liquid. The pulse width modulation is then variably adjusted based on this droplet spectrum and / or wetting by means of a control and / or regulation device or a control program stored within such a device. Manual adjustment by an operator is also possible.

[0052] The pulse width modulation or duty cycle can also be varied based on the flow rate through the spray nozzles downstream of the switching element. For this purpose, a measuring device for recording the application rate can be assigned downstream of the switching element, or at least to one of the at least two spray nozzles downstream of the switching element. The measuring device is specifically positioned downstream of the switching element in such a way that it records the quantity of spray liquid flowing through the switching element or being applied by at least one spray nozzle. The measuring device can, for example, be a flow meter and / or a volumetric flow meter. The application rate recorded by the measuring device can also be evaluated accordingly by a control program stored in a control and / or monitoring device.

[0053] The pulse width modulation and / or the duty cycle can also be varied depending on the height of the spray boom, i.e., depending on the distance between the spray boom and the crop or field. This height or distance can be detected, for example, by distance sensors and / or ultrasonic sensors mounted on the spray boom. In this context, the smaller the distance, the smaller the required amount of spray solution and the lower the duty cycle.

[0054] It is also possible for the pulse width modulation and / or duty cycle to be varied by the control device depending on the pressure level in the liquid line and / or depending on the required application rate. These controlled variables can, in turn, be recorded and monitored using a variety of monitoring devices.

[0055] Furthermore, the pulse width modulation parameters can be entered manually using an input device, or the input device can be connected to a database or similar system. The input device could be, for example, a mobile device and / or a control panel or similar.

[0056] To prevent the spray nozzles from running dry or dripping during periods when the switching element is closed, or when no spray fluid is to be dispensed, a pre-pressure valve can be assigned to, upstream of, or integrated into the spray nozzles, connecting element, nozzle assembly, branch, and / or fluid line. In particular, at least one such pre-pressure valve is assigned to the distribution system. The pre-pressure valve is designed to open only above a defined pressure. As soon as this pressure is no longer present, for example, due to the closing of the switching element, the pre-pressure valve also closes, and no further fluid is dispensed from the spray nozzles or conveyed through the distribution system. Thus, the pre-pressure valve maintains a defined back pressure in the distribution system.

[0057] The pre-tensioning valve can, for example, be a pressure relief valve. In particular, the pre-tensioning valve can be a pressure-switching valve. Furthermore, the pre-tensioning pressure or the opening pressure of the pre-tensioning valve can be greater than or equal to 0 bar, or greater than or equal to 0.2 bar and less than or equal to 5 bar. However, the opening pressure of the pre-tensioning valve can also be 0.5 bar.

[0058] Furthermore, the use of so-called drip-stop valves, which can also be integrated into the spray nozzles, would be conceivable. Such valves typically have a spring-loaded opening mechanism that only opens after a certain opening pressure is applied.

[0059] In a further development of the invention, the pump can, for example, also serve as a switching element for conveying the spray liquid through the liquid line or along the spray boom, so that the pump can convey spray liquid in a defined or definable pulse width modulation or with a variable duty cycle.

[0060] In a further development of the invention, the pulse width modulation can be varied depending on the number of spray nozzles downstream of the switching element. For example, the more spray nozzles downstream of the switching element, the lower the duty cycle. This could mean, for instance, that if the switching element has a duty cycle of 50%, the spray nozzles, due to their distance from both the switching element and each other, will have a duty cycle of 80%. Furthermore, measuring devices or the like can be assigned to at least one of the at least two spray nozzles downstream of the switching element to monitor the duty cycle.

[0061] It could also be provided that the pulse width modulation is varied depending on the embodiment or the type of spray nozzles. For example, each spray nozzle has a fixed flow cross-section, which in turn influences the application rate. Thus, it could be provided that the larger the flow cross-section of the at least two spray nozzles downstream of the switching element, the greater the duty cycle of the pulse width modulation.

[0062] Furthermore, the pulse width modulation could be varied depending on the length of the fluid lines and / or their cross-sections within the distribution system, so that the longer and / or larger the cross-section of the fluid lines, the higher the duty cycle. The spacing of the spray nozzles could also be taken into account accordingly.

[0063] Furthermore, it could be provided that the frequency of the pulse width modulation is varied depending on the number of spray nozzles downstream of the switching element and / or depending on the cross-sections of the spray nozzles and / or depending on the distances between the spray nozzles.

[0064] The at least two spray nozzles downstream of the switching element can be connected, for example, by means of a connecting element. This connecting element can also be connected to the branch of the liquid line. Alternatively, the connecting element can be connected to the nozzle assembly. It is also conceivable that the connecting element is connected to a spray nozzle and / or distribution nozzle mounted on the nozzle assembly. Furthermore, a spray nozzle and / or distribution nozzle could also be attached to the liquid line, to which the connecting element is then connected. The connecting element can also be assigned at least two spray nozzles, spaced apart from each other. The distance between the spray nozzles is greater than or equal to 10 cm and can, in particular, be 25 cm, 50 cm, and / or 100 cm.

[0065] The connecting element is designed, for example, as an L-shaped, T-shaped, V-shaped, or U-shaped element. The connecting element can also be made of one or more parts. Furthermore, the connecting element can be composed of a pipe structure.

[0066] The connection can be force-fit, form-fit, and / or material-fit. Force-fit and / or form-fit connections can include, for example, screw connections, rivet connections, and / or clamp connections, or the like. Material-fit connections can include, for example, weld connections, adhesive connections, and / or solder connections, or the like. Alternatively, combinations of force-fit, form-fit, and / or material-fit connections are conceivable.

[0067] Furthermore, the system can be configured to control the individual spray nozzles based on the overlap of the spray jet or spray cone generated by the distribution nozzles. This overlap is defined by two adjacent spray nozzles. Depending on whether this overlap is sufficient, additional distribution nozzles and / or spray nozzles can be activated. The spray cones can also be detected by sensors and evaluated using a control program stored in a control unit. The overlaps can also be defined based on the height of the spray boom above the crop; the greater the height, the greater the overlap. The distance between the spray nozzles can also be factored into the evaluation.

[0068] In particular, at least a double overlap of the spray jets or spray cones is provided, i.e., each plant or each area of ​​the field is sprayed by means of at least two spray cones.

[0069] It could also be provided that the at least two spray nozzles downstream of the switching element can in turn be switched on and / or off by means of, for example, a valve, so that, for example, only one of the at least two spray nozzles downstream of the switching element distributes the spraying fluid. Furthermore, it would also be conceivable that each of the at least two nozzle assemblies downstream of the switching element is assigned a valve, so that, for example, only the spray nozzles mounted on a nozzle assembly distribute the spraying fluid.

[0070] The spray boom, when fully extended, can have a working width of 18 meters or more. Furthermore, the distribution nozzles and their fluid lines can be divided into two or more sections. In this context, "section" means that the total working width of the spray boom can be divided into two or more segments, each of which can have its own separate fluid line or circuit. This allows, for example, individual sections or segments of the spray boom to be switched on and / or off when driving around corners or edges, preventing overlaps and thus double-treating already sprayed areas.

[0071] In a further embodiment, the spray boom can be divided into at least two or more such sections, or have at least two sections, each of which can apply spray liquids independently of one another. For this purpose, it can be provided, for example, that each section is assigned a separate liquid line and / or a separate liquid circuit. According to the invention, each section can be assigned a switching element by means of which a defined pulse width modulation can be generated at each section. In a further development of the invention, it can again be provided that the pulse width modulation, and thus the application rate, differs at the respective sections.

[0072] In one design variant, it may be provided that a partial width consists of at least one switching element and two spray nozzles and / or nozzle assemblies downstream of it.

[0073] The application rate of spray liquid can be adjusted, for example, based on the plant population; for instance, disease infestation or plant growth density can be detected by sensors, or information can be read from a database into the control unit and the application rate varied accordingly based on this information.

[0074] Furthermore, the application rate can be varied based on the sprayer's driving characteristics, so that, for example, the application rate is increased or decreased taking into account cornering and / or acceleration and / or deceleration. This is achieved by varying the pulse width modulation, or more specifically, its duty cycle.

[0075] Furthermore, according to the invention, the control of the distribution system can be based on at least two spray profiles stored in the control and / or regulation device. Each spray profile comprises or takes into account at least two parameters and / or sensor values, and if at least one parameter or sensor value of a first spray profile deviates, the distribution device is automatically controlled based on the parameters of at least one second spray profile. According to the invention, pulse width modulation, in particular its duty cycle, can also be included as a parameter in the control system. In addition, for example, the vehicle's movement characteristics, its height control, and / or its application rate can serve as further parameters.

[0076] Furthermore, the pulse width modulation parameters can be entered manually using an input device, or the input device can be connected to a database or similar system. The input device could be, for example, a mobile device and / or a control panel or similar.

[0077] Variations in the respective control and / or regulated variables can be automated using a control and / or regulated device. Alternatively, variations in the respective control and / or regulated variables can also be achieved through manual adjustment, for example, by an operator.

[0078] It should be noted that the terms "control device" and "regulation device" can refer to electronic and / or mechanical and / or pneumatic and / or hydraulic controls, which, depending on their design, can perform control and / or regulation tasks. Even though the term "regulate" is used here, it can also appropriately encompass "steer." Likewise, the use of the term "steer" can also imply "regulate."

[0079] The control device can be operatively connected to, or include, a control system and / or circuit based on electrical and / or pneumatic and / or hydraulic and / or a combination of these energy and signal transmission methods. For example, a bus system such as a CAN bus system can be used to control the control elements. Wireless communication interfaces are also conceivable.

[0080] If the distribution system according to the invention has been described previously, it should be expressly emphasized at this point that all aspects and embodiments explained in connection with the distribution system equally relate to, or can be related to, the subsequent method according to the invention. Therefore, whenever the distribution system according to the invention is mentioned in the description or in the definitions of the claims, this applies equally to the method according to the invention. Conversely, the same applies, so that all aspects explained in connection with the method according to the invention can equally be related to the distribution system.

[0081] To solve these problems, the invention also proposes a method for use in an agricultural field sprayer. This method, which is used for applying spray liquids, comprises at least the following steps: - Provision of the respective spraying fluid by means of at least one storage container, - Pumping the spraying fluid and supplying spray nozzles mounted on a spray boom with spraying fluid by means of a pump with variably adjustable pressure from the reservoir along a liquid line guided on a spray boom mounted on the field sprayer, - Atomization of the spray liquid by means of at least two spray nozzles spaced apart from each other, which spray nozzles are in fluid connection, downstream of a switching element controlled by a variably variable pulse width modulation, which switching element is assigned to or downstream of the liquid line.

[0082] The process steps described here can be carried out continuously on the field sprayer.

[0083] The pressure at which the respective spray fluid is conveyed along the fluid line can be variably changed and / or regulated to a largely constant value. In particular, it can be intended that the respective pressure remains constant depending on the spray nozzles used and the respective pulse width modulation, i.e., that it is regulated to a constant pressure in the fluid line or distribution system.

[0084] Furthermore, appropriate sensors or monitoring devices can be present to monitor the respective pressure in the liquid line or distribution system. In particular, this pressure can serve as a control variable for a control program stored in a control and / or regulation device. The method can also provide for the respective pressure in the liquid line to be varied according to the pulse width modulation or the duty cycle of the switching element.

[0085] The pulse width modulation or duty cycle can also be varied based on the flow rate through the spray nozzles downstream of the switching element. For this purpose, a measuring device for recording the application rate is assigned downstream of the switching element, or at least to one of the at least two spray nozzles downstream of the switching element. The measuring device can be, for example, a flow meter and / or a volumetric flow meter. The application rate recorded by the measuring device can also be evaluated accordingly by means of a control program stored in a control and / or monitoring device.

[0086] The pulse width modulation and / or the duty cycle can also be varied depending on the height of the spray boom, i.e., depending on the distance between the spray boom and the crop or field. This height or distance can be detected, for example, by distance sensors and / or ultrasonic sensors mounted on the spray boom. In this context, the smaller the distance, the smaller the required amount of spray solution and the lower the duty cycle.

[0087] It is also possible for the pulse width modulation and / or duty cycle to be varied by the control device depending on the pressure level in the liquid line and / or depending on the required application rate. These controlled variables can, in turn, be recorded and monitored using a variety of measuring instruments or monitoring devices.

[0088] It could also be provided that the at least two spray nozzles downstream of the switching element can be switched on and / or off by means of a valve, so that, for example, spray liquid is distributed only by one of the at least two spray nozzles downstream of the switching element, or that spray liquid is atomized only by one spray nozzle. Furthermore, it would also be conceivable that each of the at least two nozzle bodies downstream of the switching element is assigned a valve, so that, for example, spray liquid is distributed only by the spray nozzles mounted on a single nozzle body.

[0089] In a further embodiment, the spray boom can be divided into at least two or more sections, each of which can apply spray liquids independently of the others. For this purpose, each section can be provided with a separate liquid line and / or a separate liquid circuit. According to the invention, each section can be assigned a switching element by means of which a defined pulse width modulation is generated at each section. In a further development of the invention, the pulse width modulation, and thus the application rate, can again be different at the respective sections.

[0090] The preferred embodiments and features of the invention described above can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying drawings. The relative sizes of the individual elements in the figures do not always correspond to the actual relative sizes, as some shapes are simplified and others are enlarged for better illustration in relation to other elements. The figures show: Fig. 1 A side view of a field sprayer designed as a self-propelled machine. Fig. 2A a schematic view of an embodiment of a distribution system according to the invention with two switching elements connected to a liquid line and two spray nozzles downstream of each switching element. Fig. 2B a schematic view of an embodiment of a distribution system according to the invention with two switching elements connected to a liquid circuit and three spray nozzles downstream of each switching element. Fig. 3 a block diagram of an embodiment of a distribution system according to the invention with control device. Fig. 4 a diagram of pulse width modulation and its relationships.

[0091] The in the Fig. 1, Fig. 2, Fig. 3 to Fig. The four embodiments shown are at least partially identical, so that similar or identical parts are provided with the same reference numerals, and reference is also made to the description of the other embodiments or figures to avoid repetition. The illustrated embodiments merely represent examples of how the distribution system and the method according to the invention can be designed and do not constitute an exhaustive limitation.

[0092] One design variant of a field sprayer 10 designed as a self-propelled machine is shown in the side view of the Fig. 1. The field sprayer 10 shown here can be equipped with the distribution system 12 according to the invention for applying spray liquids and / or the method for applying spray liquids can be carried out. The in Fig. Figure 1 shows a field sprayer 10, which first shows wheels 14 by means of which the field sprayer 10 can be moved across a field or soil surface 14. The field sprayer 10 also includes a drive unit 16, a cab 18, and a frame 20 that supports the components of the field sprayer 10.

[0093] For storing and providing the respective plant protection or spraying liquid, the field sprayer 10 is also equipped with a storage tank 22. For distributing the spraying liquid, the field sprayer is also equipped with a spray boom 28 at the rear, extending transversely to the direction of travel 24 and adjustable in height by means of at least one actuator 26.

[0094] A number of nozzle assemblies (not shown) with distribution nozzles and / or spray nozzles are attached to the spray boom 28. These distribution nozzles and / or spray nozzles each produce a downward spray jet 30 directed towards a stand of plants 28. The spray liquid is atomized by means of the spray nozzles.

[0095] Further details of the distribution system according to the invention can be seen from the schematic views of the Fig. 2A & 2B as well as from the block diagram of the Fig. 3. Whereby the Fig. 2B opposite the Fig. 2A has a liquid circuit 33. The distribution systems 12 shown here can, for example, also be assigned to a partial width of the spray boom 28.

[0096] The distribution systems 12 comprise a storage tank 22, which supplies the spray liquid to be applied. The individual components of the distribution system 12 are connected by one or more liquid lines 32. The liquid line 32 can also form a liquid circuit 33, meaning that the liquid line 32 flows back into the storage tank 22. The respective flow direction of the spray liquid is illustrated by arrows.

[0097] The spray fluid is conveyed from the reservoir 22 to the respective nozzle bodies and / or spray nozzles 34 via the fluid lines 32. A pump 36 is also interposed between the reservoir 22 and the nozzle bodies and / or spray nozzles 34, and the pressure at which the spray fluid is conveyed within the fluid line 32 can be variably changed by means of this pump 36.

[0098] According to the Fig. Two switching elements 38 branch off from liquid line 32, 2A and 2B, for example, by means of a branch integrated into liquid line 32. Two spray nozzles 34, spaced apart from each other, are arranged downstream of or operatively connected to the switching elements 38. The switching elements 38 are also spaced apart from each other. For example, the distance A between the switching elements 38 can be 50 cm or 100 cm, while the distance B between the spray nozzles can be 25 cm or 50 cm. Distance A is dependent on distance B; that is, the greater the distance B, the greater the distance A, and vice versa.

[0099] According to the exemplary embodiments of the Fig. 2A & 2B, the switching elements 38 could also be assigned to a nozzle assembly and / or a connecting element. Such nozzle assemblies are known as single, double, and / or multiple nozzle assemblies, to which one, two, and / or more spray nozzles can be attached. Corresponding connecting elements could also be attached to the nozzle assembly. It could also be provided that the liquid line 32 opens into two nozzle assemblies, to which at least one distribution nozzle is attached, and to which distribution nozzles at least two spaced-apart spray nozzles 34 are arranged for atomizing the spray liquid or for generating a spray pattern 30.

[0100] From the Fig. Figure 3 further illustrates another embodiment of a distribution system 12 in which a switching element 38 is associated with the liquid line 32, and a plurality of spray nozzles 34 are arranged downstream of or operatively connected to this switching element 38. The spray nozzles 34 have, for example, a distance B between them which is greater than or equal to 10 cm and is, for example, 25 cm, 50 cm, and / or 100 cm. The spray nozzles 34 atomize the spray liquid, or rather, they generate a downward-directed spray jet 30.

[0101] The switching elements 38 according to the Fig. 2 & 3 are each controlled with a defined or definable pulse width modulation, i.e., depending on this pulse width modulation, spray fluid is directed to the at least two spray nozzles 34 downstream of the switching element 38. The pulse width modulation of the switching elements 38 is also transmitted to the spray nozzles 34 downstream of the switching element 38 via this operative connection.

[0102] To prevent, in particular, the spray nozzles 34 from running dry or dripping during periods when the switching element 38 is closed, a pre-charge valve 40 can be assigned to, located upstream of, or integrated into the spray nozzles 34 and / or the nozzle assembly and / or the fluid line 32. Each pre-charge valve 40 is designed to open only above a defined pre-charge pressure or opening pressure. In particular, such a pre-charge valve 40 is assigned to the distribution system 12. This pre-charge valve 40 is also located downstream of the switching element 38.

[0103] A pump 36 can be provided to vary the pressure in the liquid line. The pump 36 can be hydraulically and / or pneumatically and / or electrically operated and can be controlled or regulated accordingly by means of a control unit 42. Furthermore, appropriate measuring or monitoring devices 44 can be provided to monitor the respective pressure. In particular, this pressure can serve as a control variable for a control program stored in the control unit 42.

[0104] The variation of the pulse width modulation can be performed, for example, manually by an operator or automatically. In particular, the variation of the pulse width modulation is achieved by means of a control and / or regulation device 42. The control device 42 can be operatively connected to, or include, an electrical and / or pneumatic and / or hydraulic and / or a combination of these energy and signal transmission methods. For example, a bus system such as a CAN bus system can be provided for controlling the control elements 38, whereby, according to the Fig. 3 this connection is schematically represented by dashed lines.

[0105] Pulse width modulation can also be varied, for example, depending on the height of the spray boom and / or the pressure level in the liquid line and / or the required application rate, using the control unit 42. These control variables can also be recorded and monitored using various monitoring devices.

[0106] Furthermore, the pulse width modulation parameters can be entered manually using an input device 46, or the input device 46 can be connected to a database or the like. The input device can be, for example, a mobile device and / or an operator panel or the like.

[0107] Further details of pulse width modulation and its relationships can be found in the diagram of the Fig. 4 stands out.

[0108] Pulse width modulation is performed at a frequency of 1 Hz, although other frequencies are also possible, such as 50 Hz, 100 Hz, 200 Hz, or similar. The frequency can be an optimization parameter stored in the control and / or regulation unit, which may be defined depending on the respective components of the distribution system 12. It is also possible for the frequency to be increased or decreased depending on the individual spray nozzles 34.

[0109] The output rate is increased or decreased based on a duty cycle. This duty cycle is determined by the ratio between the pulse duration t and the period T. The duty cycle is therefore defined as t / T. The duty cycle is also expressed as a percentage (%). In simpler terms, this means that the duty cycle defines the time the switching element is open.

[0110] In the exemplary embodiment, a duty cycle of 80% is assumed for a frequency of 1 Hz, meaning that the switching element 38 is theoretically open for 0.8 s and closed for 0.2 s. However, since switching elements 38 generally exhibit inertia, they are usually not completely closed due to the high frequencies, but rather only to a corresponding intermediate position between the closed and open positions, depending on the frequency and the duty cycle. With regard to the flow rate of spray fluid, this means that an average value MW is established between the open position SO of the switching element 38 and the closed position SG of the switching element 38. Thus, the application rate of spray fluid also settles at this average value MW, which in turn means that the flow rate or...The application rate of spray liquid is reduced compared to the open position SO of switching element 38. As can be seen from the diagram, the application rate can be reduced in particular by increasing the duty cycle or, in particular, by increasing the pulse duration t.

[0111] Furthermore, in Fig. 4. In addition, a signal of the closing or opening mechanism of the switching element 38, which is set by the inertia of the switching element 38, is also shown, which in the exemplary embodiment of the Fig. 4. For example, it forms a so-called sawtooth signal. Other signals would also be conceivable depending on the design of the switching element 38.

[0112] The invention is not limited to the preferred embodiments described above. Rather, a multitude of variants and modifications are possible, which also make use of the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and the features of the dependent claims independently of the referenced claims. In particular, the features of the independent claims are each disclosed independently of one another. In addition, the features of the dependent claims are also disclosed independently of all features of the respective independent claim 1 or of method claim 20. Reference symbol list 10 field sprayers 12 distribution system 14 Soil surface 16 Drive unit 18 cabins 20 frames 22 storage containers 24 Direction of travel 26 Actuator 28 plant population 30 spray jets 32 Liquid line 33 Fluid Cycle 34 Spray nozzle 36 Pump 38 switching element 40 Preload valve 42 Control device / Control device 44 monitoring equipment 46 Input device t pulse duration T Period MW average SO open position switching element SG closed position switching element SZ sawtooth signal

Claims

Distribution system (12) for an agricultural field sprayer (10) for applying spray liquids, with at least one reservoir (22) for providing the respective spray liquid, wherein the spray liquid is conveyed from the reservoir (22) along a liquid line (32) mounted on a spray boom attached to the field sprayer (10) by means of a pump (36) with variably variable pressure and / or by means of pressure regulated to a constant value, thereby supplying spray nozzles (34) with spray liquid, wherein a switching element (38) controlled by means of a variably variable pulse width modulation is assigned to or downstream of the liquid line (32), and that at least two spray nozzles (34) spaced apart from each other and in fluid communication with it are downstream of the switching element (38), characterized in thatthat the pulse width modulation is varied depending on the lengths of the fluid lines (32) and / or depending on the cross-sectional areas of the fluid lines (32). Distribution system (12) according to claim 1, characterized in that the pulse width modulation is defined by a duty cycle resulting from a ratio of pulse duration (t) and a period duration (T) and by a frequency. Distribution system (12) according to claim 1 or 2, characterized in that an increase in the application rate is achieved by increasing the duty cycle, in particular by increasing the pulse duration (t) and that a decrease in the application rate is achieved by decreasing the duty cycle, in particular by decreasing the pulse duration (t) Distribution system (12) according to one of the preceding claims, characterized in that the frequency is increased or decreased depending on the respective distribution nozzle and / or spray nozzle. Distribution system (12) according to one of the preceding claims, characterized in that the frequency of the pulse width modulation is varied according to the number of spray nozzles (34) downstream of the switching element (38) and / or according to the cross-sections of the spray nozzles (34) and / or according to the distances between the spray nozzles (34). Distribution system (12) according to one of the preceding claims, characterized in that the pulse width modulation or the duty cycle is changed on the basis of the flow rate through the spray nozzles (34) downstream of the switching element (38). Distribution system (12) according to one of the preceding claims, characterized in that a monitoring means or measuring means for recording the application rate is assigned downstream of the switching element (38) and / or at least one of the at least two spray nozzles (34) downstream of the switching element (38). Distribution system (12) according to one of the preceding claims, characterized in that a variation of the pulse width modulation and / or the duty cycle is carried out depending on a height guidance of the spray boom and / or depending on the pressure level in the liquid line (32). Distribution system (12) according to one of the preceding claims, characterized in that at least one pre-tensioning valve (40) is assigned to the distribution system (12). Distribution system (12) according to one of the preceding claims, characterized in that the pre-tensioning valve (40) has a pre-tensioning pressure or an opening pressure which is greater than or equal to 0 bar or which is greater than or equal to 0.2 bar and which is less than or equal to 5 bar, but in particular is 0.5 bar. Distribution system (12) according to one of the preceding claims, characterized in that the pulse width modulation is varied depending on the number of spray nozzles (34) downstream of the switching element (38). Distribution system (12) according to one of the preceding claims, characterized in that the pulse width modulation is varied depending on the embodiment or depending on the type of spray nozzles (34). Distribution system (12) according to one of the preceding claims, characterized in that the at least two spray nozzles (34) downstream of the switching element (38) are connected by means of a connecting element. Distribution system (12) according to one of the preceding claims, characterized in that the connecting element is also connected to the branch of the liquid line (32) and / or that the connecting element is connected to the nozzle stock and / or that the connecting element is connected to a spray nozzle (34) and / or distribution nozzle attached to the nozzle stock. Distribution system (12) according to one of the preceding claims, characterized in that the connecting element is designed as an L-shaped, T-shaped, V-shaped or U-shaped element. Distribution system (12) according to one of the preceding claims, characterized in that the at least two spray nozzles (34) downstream of the switching element (38) can be switched on and / or off by means of a valve and / or that the at least two nozzle stacks downstream of the switching element (38) are again assigned a valve. Distribution system (12) according to one of the preceding claims, characterized in that the spray boom has at least two partial widths, each of which partial widths can apply spray liquids independently of one another, wherein each partial width is assigned a switching element (38) by means of which a defined pulse width modulation is generated at each partial width. Distribution system (12) according to one of the preceding claims, characterized in that the at least two spray nozzles (34) and / or nozzle manifolds downstream of the switching element (38) are arranged at a minimum distance from each other of 10cm, but in particular at a distance of 25cm and / or 50cm and / or 100cm from each other. A method for use in an agricultural field sprayer (10) for the application of spray liquids comprising the steps of: - providing the respective spray liquid by means of at least one reservoir (22), - conveying the spray liquid and supplying spray nozzles (34) mounted on a spray boom with spray liquid by means of a pump (36) with variably variable pressure and / or by means of pressure regulated to a constant value from the reservoir (22) along a liquid line (32) guided on a spray boom mounted on the field sprayer (10), - atomizing the spray liquid by means of at least two spray nozzles (34) spaced apart from each other, which spray nozzles (34) are in fluid connection downstream of a switching element (38) controlled by a variably variable pulse width modulation, which switching element (38) is assigned to or downstream of the liquid line (32);characterized in that the pulse width modulation is varied depending on the lengths of the fluid lines (32) and / or depending on the cross-sectional areas of the fluid lines (32). Method according to claim 19, characterized in that a monitoring means or measuring means for recording the application rate is assigned downstream of the switching element (38) and / or at least one of the at least two spray nozzles (34) downstream of the switching element (38). Method according to claim 19 or 20, characterized in that a variation of the pulse width modulation and / or the duty cycle is carried out depending on a height guidance of the spray boom and / or depending on the pressure level in the liquid line (32). Method according to one of claims 19 to 21, characterized in that the at least two spray nozzles (34) downstream of the switching element (38) can be switched on and / or off by means of a valve and / or that the at least two nozzle stacks downstream of the switching element (38) are again assigned a valve. Method according to one of claims 19 to 22, characterized in that the spray boom has at least two partial widths, each of which can independently apply spray liquids, wherein each partial width is assigned a switching element (38) by means of which a defined pulse width modulation is generated at each partial width.

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