AU2021238641A1 - Method for spreading slurry and sprayer suitable for implementing same - Google Patents

Abstract

The subject of the present invention is a method for spraying slurry with the aid of a sprayer having a tank (1) containing either slurry or a carrier liquid (1a), a spray bar (2) provided with spray nozzles (2a), a feed circuit (3) having a main pipe (3a) forming, in the spray bar (2), a spray loop (30a) on which are mounted said nozzles (2a), a pump (3b), a regulator (4), a control device that is able to manage the different use modes of the sprayer and a measurement system (4b), if necessary a direct injection system (5). It consists, in a step of initiating spraying that is carried out prior to the spraying step and with the aid of said sprayer, which also comprises an air vent valve (7) mounted on the spray loop (30a), in expelling the air present in the spray bar (2), the nozzles of which are closed, with the slurry or the carrier liquid (1a) and in evacuating the air with the aid of the air vent valve(s) (7). A further subject of the present invention is a sprayer suitable for implementing said method.

Description

Description Title of the invention: Method for spreading a mixture and sprayer suitable for implementing same

[0001][The present invention relates to the field of agricultural machinery and in particular of spraying equipment for spreading, and its subject is a method for spreading a mixture and a sprayer suitable for implementing the method.

[0002] The sprayer is the equipment for spreading over the ground or over the plants fertilizer or plant protection products sprayed in the form of droplets. Spraying is that operation whereby a certain quantity of product(s) is spread as droplets and distributed evenly over the ground or the plants by means of a sprayer.

[0003] Preparing a mixture to be sprayed by mixing active substances with a carrier liquid such as fresh water is known in the agricultural field. After the sprayer tank has been filled with a carrier liquid such as fresh water, the active substance(s) is (are) added in the tank, on a suitable area on the farm, to obtain the mixture. This operation requires the user to wear suitable protective clothing so as not to come into contact with the active product while it is being mixed in. The mixture is transported in the sprayer tank to the field for spraying on the targets (ground or plants) in more-or-less fine droplets depending on the purpose of the treatment.

[0004] The tank is fitted on a chassis mounted on or towed by a vehicle such as a tractor, or mounted on a self-propelled chassis. The sprayer comprises a chassis, a tank, a spray boom fitted with spray nozzles and which can be made of one or more articulated arms. Each spray nozzle or section of spray nozzles has a closing element that can be instructed to open or close.

[0005] The sprayer also comprises a spray circuit comprising a main pipe to convey the mixture from the tank to the spray boom, i.e. to the spray nozzles. The sprayer also comprises a pump and a pressure and/or flow regulator that make it possible to convey the pressurized mixture to the spraying nozzles. The main pipe ends in the spray boom with a spray loop in which the spray nozzles are mounted.

[0006] The user is obliged to keep to the procedures required by regulations. For example, rinsing the sprayer tank is an essential and systematic operation after each spraying step. At the end of the spraying operation, mixture remaining at the bottom of the tank is diluted with fresh water. This diluted volume circulates throughout the spray boom and is sprayed onto the field. This operation must be requires a rinsing tank to be present. Furthermore, to keep the volume of mixture remaining in the tank to a minimum, the user must prepare the exact volume of mixture. In practice however, this is not necessarily simple, as an amount sufficient to treat the entire area of the field must be prepared, without the remaining volume of mixture being too large at the end of the treatment.

[0007] The direct injection spraying technique, using a direct-injection system that the sprayer also comprises, makes it possible to overcome these drawbacks. In this direct injection principle, the sprayer tank only ever contains carrier liquid e.g. fresh water, never any mixture. The mixture is made outside the tank. The active product(s) is/are stored in one or more distinct containers and injected in quasi real time using the direct-injection system, i.e. during the movement of the sprayer over the area to be treated, into the main pipe to be mixed with the carrier liquid coming from the tank. The active product(s) is (are) injected downstream from the pump and upstream from the pipe loop such as to supply the latter with mixture made in this way outside the tank and resulting from mixing the carrier liquid and the injected active product(s).

[0008] In these two sprayer variants, i.e. with or without a direct-injection system, the boom must also be primed to be able to start spraying immediately (or with no time out). On a conventional boom, priming is not instantaneous; therefore spraying mixture across the width of the boom only starts after travelling several metres. Another problem concerns preventing the risks of clogging the nozzles and the spray loop in the spray boom. To achieve this, it is known to eliminate the deposit areas where the mixture may stagnate, especially when spraying has stopped. This is the case, for example, for a U-turn, where spraying is momentarily stopped while the U-turn is being completed. When the mixture is at a standstill in the spray boom, the particles in suspension in the water tend to sediment and cause clogging of the nozzles.

[0009] To solve these problems when spraying has stopped (closing every nozzle), in sprayers without direct injection, the mixture is made to circulate continuously. A system for returning to the tank comprising a back pipe located at the end of the boom makes it possible to make the mixture circulate permanently. The back pipe also makes it possible to prime the boom to be able to start spraying with no time out.

[0010] The direct injection spraying technique does not make it possible to add such a back Dine to the tank. since the tank contains carrier liquid. such as fresh water.

and not mixture. To overcome this drawback, a known solution, such as the one that is the subject of document W02014200896, consists of using an additional tank located between the tank containing the carrier liquid and the spray boom. The additional tank is intended to contain the mixture and to return the mixture at the end of the boom to the additional tank. Adding a tank so that the mixture is not at a standstill in the boom on one hand involves recycling the mixture present in the additional tank into the boom during the spraying operation and on the other hand, increases the dead volumes at the end of the treatment, since the volume of mixture to be diluted at the rinsing step is larger.

[0011] The present invention aims to overcome these drawbacks by proposing a method for spreading a mixture from a sprayer that makes it possible to start spreading immediately and at the right concentration, while keeping down the risks of the active products sedimenting in the spray boom.

[0012] Method for spreading a mixture according to the present invention, using a sprayer, the said mixture resulting from mixing active product(s) with a carrier liquid, the said sprayer comprising:

[0013] - a tank containing either the mixture to be sprayed, or a carrier liquid intended to form the mixture to be sprayed;

[0014] - a spray boom fitted with spray nozzles;

[0015] - a supply circuit comprising a main pipe forming a spray loop in the spray boom, in which spray loop the said nozzles are mounted, as well as a pump able to deliver, in a spraying step, a quantity of carrier liquid or of mixture defined per time unit and/or at a defined pressure to supply the spray loop;

[0016] - a regulator for adjusting, controlling and/or keeping constant the application of the mixture thus sprayer per unit of surface area;

[0017] - a control device able to manage the sprayer's various methods of use; and

[0018] - a metering system.

[0019] Where applicable, in the case that the tank contains the carrier liquid intended to form the mixture to be sprayed, the sprayer also comprises a direct-injection system able and intended to inject at least one active product into the main pipe to mix it with the carrier liquid and form the mixture to be sprayed downstream from the tank and upstream from the spray loop.

[0020] The said method is essentially characterized in that it consists, from the said flushing out, during a spraying priming step, the air present in the spray boom with the mixture or the carrier liquid, and evacuating the air using the air purge(s), the said priming step being carried out before the spraying step and in which priming step the nozzles are closed.

[0021] The subject of the present invention is also a sprayer for spreading a mixture, the said mixture resulting from a mix of active product(s) with a carrier liquid, the said sprayer comprising:

[0022] - a tank able and intended to contain either the mixture or a carrier liquid intended to form the said mixture;

[0023] - a spray boom fitted with spray nozzles;

[0024] - a supply circuit comprising a main pipe forming in the spray boom a spray loop, in which are mounted the said nozzles and a pump able to deliver, in a spraying step, a quantity of carrier liquid or of mixture determined per time unit and at a defined pressure to supply the spray loop;

[0025] - a regulator making it possible to adjust, control and/or keep constant the application per unit of surface area of the mixture.

[0026] - a control device able to manage the sprayer's various methods of use; and

[0027] - a metering system.

[0028] Where applicable, in the case that the tank is intended to contain carrier liquid intended to form the mixture to be sprayed, the said sprayer also comprises a direct-injection system able and intended to inject at least one active product into the main pipe to mix it with the carrier liquid to form the mixture to be sprayed downstream from the tank and upstream from the spray loop,

[0029] the sprayer being characterized in that it also comprises at least one air purge mounted in the spray loop to be able to exhaust the air present in the said spray loop.

[0030] The invention will be better understood from the following description, which refers to a preferred embodiment given as a non-limiting example and explained with reference to the attached schematic drawings, in which:

[0031] [Fig. 1] shows a schematic view of the sprayer according to the present invention in an embodiment comprising a direct-injection system for active product(s) during the spraying priming step of the spray boom;

[0032] [Fig. 2] shows the sprayer shown in figure 1 with in addition the control device, in the spraying step that follows the priming step;

[0033] [Fig. 3] shows the sprayer shown in figure 1 in the anti-clogging step allowing the mixture to be made to circulate while the spraying step is temporarily stopped/interrupted;

[0034] [Fig. 4] shows a schematic view of the sprayer shown in figure 1 at the start of the step of draining the air from the spray boom, following the spraying step.

[0035] [Fig. 5] shows the sprayer shown in figure 4 at the end of the step of draining the air with the nozzles gradually closing;

[0036] [Fig. 6] shows the sprayer shown in figure 1 in a step of rinsing the spray boom with water, following the draining step.

[0037] [Fig. 7] schematically shows the division into sections of a lateral portion of a spray boom of a sprayer according to the present invention;

[0038] [Fig. 8] is a flowchart showing the various steps in the method according to the present invention.

[0039] The attached figures show the steps of the method according to the present invention for spreading a mixture using a sprayer, which is also the subject of the present invention and suitable for implementing the said method.

[0040] The said sprayed mixture is the result of mixing active product(s) and a carrier liquid 1a. Preferably, the carrier liquid 1a is fresh water, but could be another liquid or liquid solution, preferably without active product(s) but possibly containing other products and/or one or more active product(s)

[0041] Such a sprayer according to the present invention comprises a tank 1 configured to contain either the mixture to be sprayed or a carrier liquid 1a intended to make the mixture lb to be sprayed (by mixing, downstream from the tank 1 of the said carrier liquid 1a with one or more active product(s)), a spray boom 2 fitted with spray nozzles 2a and a supply circuit 3 comprising a main pipe 3a, forming in the spray boom 2 a spray loop 30a, in which the nozzles 2a are mounted. The sprayer also comprises a pump 3b to convey the carrier liquid 1a or the mixture 1b from the tank 1 to the said nozzles 2a and a regulator 4. This is a pressure and/or flow regulator such as valves. The pump 3b makes it possible to ensure the displacement of the carrier liquid 1a and the regulator 4 makes it possible to adjust the spraying pressure or flow rate. The adjustment may be carried out continuously. The regulator 4 causes a larger or smaller portion of the flow rate of the pump 3b to return into the tank in order to ensure a regular throughput at the spray boom 2.

[0042] The nozzle 2a is a critical element of the sprayer: much of the efficiency of the treatments depend on it. "Nozzle 2a" refers to any device that transforms a flow of liquid into a lot of drops that make up the jet. The nozzle's role is to calibrate and direct the mixture in droplets for the most uniform spraying possible. The nozzles 2a are removable and interchangeable parts fastened on nozzle supports. Each nozzle 2a can be fitted on a single nozzle support. It is usual to use a nozzle support with multiple heads of the rotary type that carries at least two nozzles and makes it possible to switch quickly from one nozzle type to another, depending on the kind of spraying. Advantageously, the nozzle support is used with an anti-drop element that prevents leakage and waste of mixture lb at the nozzles 2a when spraying is temporarily interrupted or at the end of the treatment. The anti-drop element is a mechanical, electrical, or pneumatic means. Closing each nozzle 2a can be done with a membrane or flap type anti-drip valve. For multiple-head nozzle supports, each nozzle 2a can be switched off/closed to stop it emitting liquid, making it easier to change and clean thanks to the membrane anti-drip.

[0043] One will understand that, where the tank 1 is intended to contain the mixture 1b to be sprayed, the latter is made by filling the tank 1 with carrier liquid 1a, then by adding, manually for example, one or more active product(s) in the tank 1 to mix them with the carrier liquid 1a. Where the tank 1 is intended to contain the carrier liquid 1a, i.e. without addition of any active product(s) in the tank 1, then the said mixture 1b is made outside the tank 1 by using a direct-injection system 5 to inject active product(s) into the main pipe 3a conveying the carrier liquid 1a coming from the tank 1 to mix it (them) with the latter and make the mixture 1b downstream from the tank 1 and upstream from the spray loop 30a.

[0044] The sprayer also has a control device 9, shown in figure 2, able to manage the sprayer's various methods of use, such as filling, spraying, rinsing, and mixing in, where applicable. A position of the supply circuit 3 valves and/or taps can correspond to each method of use of the sprayer. The sprayer, and especially the supply circuit 3, can also be fitted with a metering system 4b, as shown in the attached figures, at the location of the spray loop 30a. The metering system 4b makes it possible to adjust the spraying pressure and/or flow rate. The user may be advised, through the control device 9, of the pressure and/or flow rate in the spray loop 30a, thanks to the metering systems 4b. The various steps of the method for spreading a mixture lb from a sprayer are shown in the flowchart of figure 8. The key steps are: filling the tank 1; priming the spraying; spreading the additional step, between the filling and spreading steps, of adding the active products. The priming step is scheduled before the spraying or spreading step, so that spraying is carried out without delay when the nozzles 2a open. During the spraying step, when all the spray nozzles 2a are closed, it is usual to provide a circulation or anti-clogging step for the mixture 1b inside the spray loop 30a. A step of draining the air from the spray boom 2 can be performed after the spraying step. This step of draining the air is optional; its benefit is to reduce the number of rinses. A new step of draining the air from the spray boom 2 with air can be performed after the rinsing step. For the draining and the rinsing steps, the spray nozzles 2a are open to remove air and diluted volume. During the filling, priming and anti clogging steps, the nozzles 2a are closed so as not to spread any mixture 1b and not pollute the environment. Optional steps are shown in dotted lines on the flowchart.

[0045] In the embodiment shown in the figures, the sprayer may also be fitted with a direct-injection system 5 when the tank 1 is provided to contain a carrier liquid la and not mixture 1b. This direct-injection system 5 is able to be controlled to inject one or more active product(s) into the main pipe 3a and to mix it (them) with the carrier liquid 1a contained in and coming from the tank 1. It is possible, for example, to carry out localized treatments and to dose three to four products simultaneously. With this direct-injection system, the tank 1 is filled with carrier liquid 1a, e.g. fresh water, and the active product(s) is/are stored separately, for example in an original tank or container (canister). Mixing of the carrier liquid 1a and the active product(s) is done directly in the supply circuit 3 and more specifically in the main pipe 3a. This is a delayed-mixing spraying system able to use two distinct circuits: one circuit for carrier liquid 1a, e.g. fresh water, supplied from the tank 1; and one circuit for mixture 1b resulting from the injection of the active product(s) mixed with the carrier liquid 1a. This principle makes it possible to stop the treatment even if the tank 1 of carrier liquid la is not empty, to adjust the dose during the treatment, to easily change the active product(s) between plots, and to recover the unsprayed volume of active product(s). Furthermore, there is no risk of pollution by overflow when filling the tank 1, and the risk of the operator coming into contact with active product is lower, since there is no manual preparation of mixture 1b.

[0046] The direct-injection system 5 is able to be controlled by the control device 9 during the spraying step. In addition, the direct-injection system 5 is able to manage the concentration of the mixture 1b. Its function is to provide uniform mixing of the of spraying. One interesting specificity of the direct-injection system 5 is the possibility of injecting one or more active product(s) right from the priming phase of the spray boom 2. In this way, the treatment of the targets can begin as soon as the nozzles 2a open. Such a system is more respectful of the environment, since the tank 1 contains only carrier liquid 1a, e.g. water, which is not contaminated and therefore requires no rinsing. The original canister(s) contain only active product(s), and can simply be collected at the end of the treatment.

[0047] One of the methods of use is spraying, consisting in spreading a certain quantity of mixture 1b in small droplets and distributing it evenly over the ground or plants. In this method of use, the pump 3b is able to deliver a quantity of carrier liquid 1a or of mixture 1b specified per time unit and at a defined pressure. The pump 3b sucks the carrier liquid 1a or the mixture 1b in and draws it towards the spray boom 2 and the nozzles 2a. The pump 3b may have two unpriming thresholds, namely a first threshold corresponding to the moment when the pump 3b starts to suck the air in and when the amount of mixture 1b applied per hectare is no longer known; and a second unpriming threshold corresponding to the moment when the flow rate at the nozzles 2a becomes very low. The volume of mixture lb in the tank 1 is checked with a gauge. This gauge also makes it possible to define the volume remaining in the tank The volume remaining in the tank 1 can also be defined by the second unpriming threshold of the pump 3b. A non-return valve 3c and a flowmeter 3d are arranged on the main pipe 3a. The non-return valve 3c stops the mixture returning into the tank 1; it is located just upstream of the direct-injection system 5 where applicable. The flowmeter 3d controls the flow rate in the main pipe 3a. It is positioned between the pump 3b and the non-return valve 3c.

[0048] The pressure regulator 4 makes it possible to pre-set, control and/or keep constant the application of the carrier liquid la or mixture lb per unit of surface area. The control device 9 may also comprise the flowmeter 3d, able to control the quantity of mixture lb spread.

[0049] The spray boom 2 may comprise at least one spray arm and the or each spray arm comprises the or at least one of the air purge(s) 7.

[0050] A sprayer according to the present invention can be a mounted, towed, or self propelled sprayer, not shown in the attached figures. For a mounted sprayer, all the elements making up the sprayer are carried by a tractor. It is connected to the tractor by a three-point hitch. A sprayer is said to be towed when the sprayer or its chassis has an axle that allows for a support point on theground, and the tractor's hitch only bears a portion of the load. For self-propelled sprayers, the vehicle or machine is able to move using its own means. The chassis can carry the tank 1 and a support frame, on which the spray boom 2 can be fixed. The spray boom 2 can be made up of several portions, for example three portions, namely a middle portion and two side portions, which, once folded, facilitate the sprayer's movement on the road. These portions operate independently from one another, such that the spreading width can be adjusted as needed by means of a dispenser. The three portions of the spray boom 2 can be connected to a dispenser, and one or two portions can be closed off when the width to be treated is smaller than the size of the spray boom 2. The support frame can also be split into three portions, and fitted with mechanisms allowing opening/deploying and folding of the spray boom 2. Advantageously, the two side portions can be further subdivided into sections, for example three sections T1, T2, T3, as can be seen in figure 7, made up of a middle arm, an outer arm, and a safety arm. The safety arm is positioned outermost; it is able to fold when encountering an obstacle. Figure 7 shows the middle portion, and only one side portion of the spray boom 2.

[0051] The sprayer may also comprise a compressed air system 6 able and intended to inject compressed air into the spray loop 30a of the spray boom 2.

[0052] In accordance with the invention, the method for spreading a mixture lb consists, based on the said sprayer according to the present invention also comprising at least one air purge 7 mounted in the spray loop 30a, during a spraying priming step (figure 1) carried out before the spraying step and in which priming step the nozzles 2a are closed, of exhausting the air from the spray boom 2 with the carrier liquid 1a or mixture 1b and removing the air using the air purge(s) 7. The air that is exhausted from the spray loop 30a is at atmospheric pressure.

[0053] Thanks to the air purge(s) 7, priming the spray boom 2 can thus be achieved simply and with no need for a back pipe between the spray loop 30a and the tank 1. The spray boom 2 is primed with carrier liquid 1a and/or mixture 1b to exhaust all the air in the spray boom 2. When the spray boom 2 is primed, it has no air in it.

[0054] Preferably, the air purge 7 is an automatic air purge able to automatically exhaust the air in the spray loop 30a. It is able to close automatically as soon as all, or practically all, the air has been exhausted from the spray loop 30a. Preferably, the air purge 7 may be positioned in the middle of the spray loop 30a, as can be seen in figures 1, 2, 4, 5, 6, 7. Alternatively, the air purge 7 may be Positioned close to the middle of the snrav loon 30a. Several airnuraes 7. for example three air purges 7, preferably automatic air purges, may be mounted on the spray loop 30a, as can be seen in figure 2, preferably distributed along the branch of the spray loop 30a comprising the nozzles 2a. As soon as the air has been exhausted from the spray loop 30a, the or each air purge 7 closes automatically and the pressure increases. The spray loop 30a also comprises a valve 2b intended to be open or closed. This valve 2b is in the open state during the priming step. This valve 2b is also open during the spraying step; it makes it possible to apply the mixture into the spray loop 30a at three points. The valve 2b is located towards the centre of the spray loop 30a. The valve 2b is closed during the anti-clogging step or the continuous circulation step.

[0055] When the pressure measured in the spray loop 30a by the metering system 4b has reached a predefined value, after the priming step, the method may consist of starting the spraying step immediately after the priming step. Indeed, once the priming step has been completed, the spraying step can start immediately, since the spray loop 30a, especially the nozzles 2a, is supplied with mixture 1b. The pressure metering system may be, for example a pressure-gauge. In practice, at the end of the priming step, the start of the spraying step is controlled by the operator. In an alternative, the spraying step can trigger automatically once the spray boom 2 is fully primed.

[0056] The number of air purges 7 can vary depending on the width of the boom 2. Preferably, the present invention may provide at least one air purge 7 per boom section. Installing several air purges 7 per portion makes it possible to reduce the priming time, as the air is exhausted more quickly outside the spray loop 30a. In this way, the air purge(s) 7 make(s) it possible to prime the spray boom 2 immediately and with the right product concentration on exit from the nozzles 2a. Preferably, one air purge 7 may be mounted on the middle portion of the spray boom 2 and one air purge 7 may be mounted on each side portion of the latter.

[0057] With reference to figures 1, 2, 3, 4, 5, 6 and 7, it can be seen that the or each air purge 7 can be positioned between two adjacent nozzles 2a (figure 1). The or one of the air purge(s) 7 may be placed in the middle.

[0058] According to the method of the invention, the spraying step follows the priming step; its purpose is to spread a predefined dose of the mixture 1b on the ground or plants. During this spraying step, the adjustment device makes it possible to spread the mixture lb constantly per unit of surface area, regardless of variations in the sMraver's seed. The accuracy of thelonaitudinal distribution. i.e. the dose beina regular over the entire width of the sprayer, also depends on this adjustment device. During application of the product in a field, it is common to stop spraying for U-turns at the end-of-field, to prevent doubling the dose applied. Spraying is then momentarily stopped by closing the nozzles 2a. The control device 9 can control the closing and opening of the nozzles 2a automatically, using a geolocation system known in the prior art. The user may also control the closing and opening of the nozzles 2a manually.

[0059] With reference to figure 3, it can be seen that the method according to the present invention may consist, in the spraying step, based on the sprayer also comprising a turbine system 8 mounted in the spray loop 30a, in an anti-clogging step, of closing the nozzles 2a to momentarily stop spraying and of activating the turbine system 8 to put in motion the mixture 1b present in the spray loop 30a and make it circulate continuously (arrows in the spray loop 30a in figure 3), by means of the said turbine system 8 in the said spray loop 30a. The turbine system 8 is mounted in the spray loop 30a. The continuous movement of the mixture 1b in the spray loop 30a makes it possible to prevent the particles in suspension, coming from the active product(s), depositing in the spray loop 30a by sedimentation and leading to clogging of the nozzles 2a. In addition, the continuous circulation of the mixture 1b in the spray loop 30a makes it possible to stir and preserve the dosage. Spraying resumes as soon as the nozzles 2a open and the turbine system 8 is stopped/deactivated.

[0060] As can be seen in figure 4, according to one feature of the invention, the method according to the present invention may consist, based on the sprayer also comprising a pressurized air injection system 6, following the spraying step, of a step of draining the air from the spray boom 2 and, more specifically the spray loop 30a, of instructing the air injection system 6 to be activated and to inject pressurized air into the main pipe 3a so as to evacuate the mixture 1b from the spray boom 2 through the nozzles 2a. This step makes it possible to evacuate the mixture lb remaining in the spray loop 30a as soon as the pump 3b is unprimed. Where applicable, this step of draining with pressurized air makes it possible to reduce the number of rinses or the quantity of rinsing liquid. The pressurized air is injected into the main pipe 3a downstream from the pump 3b. A valve may be arranged downstream from the pump 3b to avoid the pressurized air reaching the pump 3b. In this way, the pressurized air injection system 6 able to inject pressurized air into the main pipe 3a makes it possible to perform a full drainage of the spray boom 2,

Preferably it may comprise an air compressor 6a, an air reserve 6b and a solenoid valve 6c. The solenoid valve 6c is preferably positioned in the main pipe 3a, upstream of the spray loop 30a and downstream from the pump 3b.

[0061] The method may consist, following the step of draining the air, in a rinsing step of rinsing the spray loop 30a and possibly the tank 1, and of evacuating the diluted volume through the nozzles 2.

[0062] The aim is to have the smallest possible amount of mixture 1b remaining in the sprayer at the end of the treatment. If the amount of mixture lb prepared or contained in the tank 1a is properly calculated, there will be only a little mixture 1b to be evacuated from the bottom of the tank 1, and the rinsing step that follows the spraying step will be shorter. It is usual to dilute the remnants in the tank 1 with a large volume of water to rinse the tank 1. This diluted volume (mixture + carrier liquid) also circulates throughout the spray boom and is evacuated onto the field by means of the nozzles 2a. This operation makes it possible to remove the spraying residues before they dry to lower the clogging risk at the tank 1 and the spray boom 2a. Rinsing is done using mainly the carrier liquid 1a from the tank 1, if it contains the carrier liquid la without active product(s), otherwise from an additional tank, not shown on the attached figures, dedicated to rinsing and then containing fresh water or an appropriate rinsing liquid. The additional rinsing tank may be connected to the main pipe 3a by means of an additional valve system able to be controlled to supply rinsing liquid to the main pipe 3a.

[0063] Therefore, according to a particular form of the method according to the present invention, the method may consist, after the step of draining the air, in a rinsing step of exhausting the pressurized air present in the spray loop 30a either with the carrier liquid 1a contained in the tank 1, or with a rinsing liquid contained in an additional tank, not shown in the attached figures, that the sprayer may also comprise, and of exhausting the pressurized air using the air purge(s) 7.

[0064] The method may also consist, after the rinsing step, of performing another step of draining the air from the spray boom 2 with air, using the air injection system 6 by controlling the activation of the air injection system 6 to inject pressurized air into the main pipe 3a so as to evacuate the carrier liquid 1a or the diluted volume of mixture in the spray loop 30a, through the nozzles 2a. This other step of draining the air also dries the spray loop 30a.

[0065] To optimize draining the air of the spray boom 2, the method may consist, based on a sprayer according to the present invention, whose nozzles 2a are arranged along at least one row, to control, using the control device 9, the gradual closing of the nozzles 2a or their supply from one to another, preferably starting from the ends (figure 5) of each row of nozzles 2a.

[0066] Preferably, in the sequence of gradually closing the nozzles 2a, the method according to the present invention may provide for controlling, firstly, the closing of the first nozzle 2a located at each end of the row, then, secondly (figure 5), the closing of the first nozzle 2a and the second nozzle 2a located at each end of the row, and so on, until all the nozzles 2a of the row, or of the concerned row of the spray boom 2 are closed.

[0067] Of course, the invention is not limited to the example embodiment described and shown in the attached drawings. Modifications remain possible, in particular concerning the composition of the various elements or the substitution with technical equivalents without departing from the scope of protection of the invention.

Claims (12)

1. Claims

   [Claim 1] Method for spreading a mixture (1b) using a sprayer, the said mixture (1b) resulting from mixing active product(s) with a carrier liquid (1a), the said sprayer comprising: - a tank (1) containing either the mixture (1b) to be sprayed, or a carrier liquid (1a) intended to make the mixture (1b) to be sprayed; - a spray boom (2) fitted with spraying nozzles (2a); - a supply circuit (3) comprising a main pipe (3a) forming in the spray boom (2) a spray loop (30a), in which are mounted the said nozzles (2a) and a pump (3b) able to deliver, in a spraying step, a quantity of carrier liquid (1a) or of mixture (1b) defined per time unit and at a defined pressure to supply the spray loop (3a); - a regulator (4) for adjusting, controlling and/or keeping constant the application per unit of surface area of the mixture (1b); - a control device (9) able to manage the sprayer's various methods of use; and - a metering system (4b), where applicable, in the case in which the tank (1) contains carrier liquid (1a) intended to make the mixture (1b) to be sprayed, the said sprayer also comprises a direct-injection system (5) able and intended to inject at least one active product into the main pipe (3a) to mix it with the carrier liquid (1a) in order to form the mixture (1b) to be sprayed downstream of the tank (1) and upstream from the spray loop (30a), the method characterized in that it consists, based on the said sprayer also comprising at least one air purge (7) mounted in the spray loop (30a), of exhausting, during a spraying priming step, the air present in the spray boom (2) with the mixture (1b) or the carrier liquid (1a), and exhausting the air using the air purge(s) (7), the said priming step being carried out before the spraying step and in which priming step the nozzles (2a) are closed.
2. [Claim 2] Method according to claim 1, characterized in that it consists, when the pressure measured in the spray loop (30a) by the metering system (4b) has reached a predefined value, after the priming step, of starting the spraying step immediately.
3. [Claim 3] Method according to claim 1 or claim 2, characterized in that it consists in the spraying step, based on the sprayer also comprising a turbine system (8) mounted in the spray loop (30a), in an anti-clogging step, of activation of the turbine system (8) to put in motion the mixture (1b) present in the spray loop (30a) and make it circulate continuously, by means of the said turbine system (8) in the said spray loop (30a).
4. [Claim 4] Method according to any one of claims 1 to 3, characterized in that it consists, based on the sprayer also comprising an air injection system (6), following the spraying step, in a step of draining the air from the spray boom (2) with air, of controlling the activation of the air injection system (6) to inject pressurized air into the main pipe (3a) so as to evacuate the mixture (1b) present in the spray boom (2) through the nozzles (2a).
5. [Claim 5] Method according to claim 4, characterized in that it consists, following the step of draining the air, in a rinsing step, of rinsing the spray loop (30a) and where applicable the tank (1), and of evacuating the diluted volume through the nozzles (2a).
6. [Claim 6] Method according to claim 5, characterized in that it consists, following the rinsing step, of performing another step of draining the air from the spray boom 2, by controlling the activation of the air injection system (6) to inject pressurized air into the main pipe (3a) so as to evacuate the diluted volume present in the spray boom (2) through the nozzles (2a).
7. [Claim 7] Method according to any one of claims 1 to 6, characterized in that the nozzles (2a) are arranged along at least one row, and it consists of controlling the gradual closing of the said nozzles (2a) or their supply, from one nozzle to another, preferably starting from the ends towards the centre of the row of nozzles (2a).
8. [Claim 8] Sprayer for spreading a mixture (1b), the said mixture (1b) resulting from mixing an active product(s) with a carrier liquid (1a), the said sprayer comprising: - a tank (1) able and intended to contain either the mixture (1b) to be sprayed, or a carrier liquid (1a) intended to make the mixture (1b) to be sprayed; - a spray boom (2) fitted with spraying nozzles (2a); - a supply circuit (3) comprising a main pipe (3a) forming in the spray boom (2) a spray loop (30a), in which are mounted the said nozzles (2a) and a pump (3b) able to deliver, in a spraying step, a quantity of carrier liquid (1a) or of mixture (1b) defined per time unit and at a defined pressure; - a regulator (4) making it possible to pre-set, control and/or keep constant the application per unit of surface area of the mixture (1b); - qrnntrnl rvin (q) qhIn tnmannan thn snrqvnr's varinii mthnris f i jsRnri

   - a metering system (4b), where applicable, in the case in which the tank (1) is designed to contain carrier liquid intended to make the mixture (1b) to be sprayed, the said sprayer also comprising a direct-injection system 5 able and intended to inject at least one active product into the main pipe (3a) to mix it with the carrier liquid 1a in order to make the mixture (1b) to be sprayed downstream from the tank (1) and upstream from the spray loop (30a), the sprayer characterized in that it also comprises at least one air purge (7) mounted in the spray loop (30a) to be able to exhaust the air present in the latter.
9. [Claim 9] Sprayer according to claim 8, characterized in that the or one of the air purge(s) (7) is located at the middle of the spray loop (30a) or of a row of nozzles (2a).
10. [Claim 10] Sprayer according to claim 8 or 9, characterized in that it also comprises a turbine system (8) mounted in the spray loop (30a) so as to make the mixture (1b) present in the spray boom (2) circulate continuously.
11. [Claim 11] Sprayer according to any one of claims 8 to 10, characterized in that it also comprises a compressed air system (6) able and intended to inject compressed air into the spray loop (30a) of the spray boom (2).
12. [Claim 12] Sprayer according to any one of claims 8 to 11, characterized in that the spray boom (2) comprises at least one spray arm and in that the or each spray arm comprises the or at least one of the air purge(s) (7).

    1a 6 4 3b 3d 6a 3c 5 3 6c 6b 4b 3a 2b 30a

    7

    2

    Fig. 1 2a

    1a 4 6 3b 3 6a 3d 6b 3c 5 9 6c

    3a 30a

    4b 2b 7 7 7 2

    2a 1b Fig. 2

    1a

    4 3b 6 3d 6a 3c 5 3 6b 6c 3a 30b 4b 8 30a

    2b 7 2

    2a Fig. 3

    1a

    4 6 3b 3 6a 3d 3c 5 6c 6b 3a

    4b 30a

    2b 7 2

    2a Fig. 4 1b

    1a

    4 3b 6 3d 3 6a 3c 5 6b 6c 3a

    4b 30a

    2b 7

    2

    2a 1b 2a Fig. 5

    1a

    4 6 3b 3d 3 6a 5 3c 6b 6c 3a 4b 30a 302a

    2b 7 2

    2a

    Fig. 6

    1a 4 6 3b 3 6a 3d 5 3c 6b 6c 3a 2 4b 2b 7

    30a

    1b 2 a Fig. 7

    Filling Blending in

    Priming

    Circulation Spraying 8/8

    Draining

    Rinsing

    Draining

    Fig. 8