Direct injection spray assembly including direct dosing interface

Abstract

The present invention relates to a spraying assembly comprising an injection device, a first hydraulic circuit (21) for conveying the carrier liquid to a spray nozzle (3), the first hydraulic circuit (21) comprising, upstream of the spray nozzle (3), an injection section (2), a second hydraulic circuit (22) for conveying the active product to the injection device, under an injection pressure greater than the circulation pressure of the carrier liquid, the injection device comprising a direct metering interface (1) comprising at least one through-orifice opening into the injection section (2) of the first hydraulic circuit (21), and the injection device further comprising at least one corresponding actuator (4) configured to open or close each through-orifice so as to allow a determined dosage of active product to pass through the at least one orifice to be injected into the flow of carrier liquid.Abstract Figure: Figure 1.

Description

Title of the invention: Direct injection spray assembly comprising a direct dosing interface Technical field

[0001] The present invention relates to the field of agricultural spraying and more specifically relates to a direct injection spraying assembly. More particularly, the spraying assembly according to the invention comprises a direct dosing interface for active product upstream of at least one spray nozzle. STATE OF THE ART

[0002] A well-known problem in the field of agricultural spraying concerns the dosage of the active product sprayed, which must be adapted to the need. We are constantly looking for the best match between the need of a crop for phytosanitary product and the quantity of product sprayed. To this end, direct injection techniques have been developed.

[0003] Direct injection consists of injecting an active product into a continuous jet of water, directly upstream of the spray nozzle.

[0004] Document FR 2964047 A1 describes an example of a direct injection spray assembly. In this document, the presence of injectors directly upstream of the spray nozzles of a spray assembly is described. Each injector is capable of being closed by a valve in order to avoid any overdosing or underdosing. Thanks to this document, the principle of actively adjusting the flow rate of active product at each spray nozzle is known. Thus, a direct injection spray assembly is known, adapted to deliver an active product injected into a carrier liquid via a set of nozzles with a variable flow rate of active product adjusted directly at the spray nozzles.

[0005] In a known manner, in this type of known spray assembly, injectors are thus configured to inject the active product into the flow of carrier liquid, according to a desired flow rate. The injectors comprise orifices which can be opened or closed by means of actuators such as solenoid valves. The injectors are placed directly upstream of the spray nozzles.

[0006] In the state of the art relating to direct injection spray assemblies, the flow rate of active product injected into a flow of carrier liquid directly upstream of the spray nozzles is thus modulated. By controlling the flow rate of injected active product, thanks to suitable control of the injectors, it is possible to improve the prevention of overdosing or underdosing.

[0007] However, the dosage cannot be precisely, directly and continuously controlled. of active product injected into the carrier liquid flow.

[0008] There is therefore a need for a spray assembly making it possible to precisely and continuously dose the active product injected into a flow of carrier liquid, in a direct injection spray assembly.

[0009] A fortiori, there is a need for such a spray assembly which also makes it possible to have a wide range of dosages of active product in a flow of carrier liquid.

[0010] To meet at least part of this need, the invention proposes the use, in a direct injection spray assembly, of a direct dosing interface comprising a plurality of orifices, in particular nano-orifices and / or micro-orifices, in particular of different sizes, the orifices being coupled to actuators controlled so as to open or close them. This achieves precise and continuous dosing of one or more active products in a flow of carrier liquid.

[0011] The metered active products are injected into a flow of carrier liquid directly upstream of spray nozzles. PRESENTATION OF THE INVENTION

[0012] More specifically, the subject of the invention is a spray assembly comprising a first reservoir configured to contain a carrier liquid, for example water, and a second reservoir configured to contain an active product, at least one spray nozzle, at least one injection device, a first hydraulic circuit for conveying the carrier liquid from the first reservoir to the spray nozzle, under a carrier liquid circulation pressure, the first hydraulic circuit comprising, upstream of the spray nozzle, an injection section, a second hydraulic circuit for conveying the active product from the second reservoir to the injection device, under an injection pressure greater than the carrier liquid circulation pressure,the active product injection device being connected to the injection section of the first hydraulic circuit and being configured to inject the active product into a flow of carrier liquid circulating in the first hydraulic circuit, the injection device comprising, at the end of the second hydraulic circuit opposite the second reservoir, a direct metering interface comprising at least one through-orifice, preferably a plurality of through-orifices, opening into the injection section of the first hydraulic circuit, and the injection device comprising at least one actuator corresponding to the at least one orifice, configured to open or close the at least one through-orifice, so as to allow a determined dosage of active product to pass through the at least one open through-orifice of the direct metering interface to be injected into the flow of carrier liquid,so as to form a mixture composed of carrier liquid and dosed active product intended to be, sprayed via the at least one spray nozzle, for the purpose of treating crops.

[0013] Thanks to the invention, it is possible to benefit from a large dosage range of active product(s) in a carrier liquid, directly upstream of the nozzles of a spraying system. In addition, the invention makes it possible to ensure constant dosage regardless of the speed of movement of the spraying system or that of the nozzle relative to the terrain.

[0014] For example, the at least one actuator is a piezoelectric actuator.

[0015] For example, the at least one actuator is a pneumatic actuator and the assembly spraying includes a compressed air circuit to enable the actuation of pneumatic actuators.

[0016] In particular, the at least one actuator is a pneumatic actuator with piezoelectric actuation.

[0017] For example, the at least one actuator is a solenoid valve.

[0018] Advantageously, the at least one actuator is controlled in opening and closing by a pulse width modulation generator.

[0019] Advantageously, the injection pressure is at least one bar higher than the carrier liquid circulation pressure.

[0020] In practice, the difference between the injection pressure and the circulation pressure depends in particular on the viscosity of the active product compared to that of the carrier liquid.

[0021] In particular, the assembly comprises a plurality of orifices and the orifices do not all have the same diameter, the different diameters of the orifices being in particular between 50 μm and 300 μm.

[0022] According to one embodiment, the spray assembly comprises a plurality of orifices and a set of corresponding actuators, and further comprises a calculation unit for determining, from a dosing instruction, the quantity of active product to be injected into the flow of carrier liquid and for controlling the opening and closing of the corresponding number of orifices of the direct dosing interface.

[0023] According to one embodiment, the calculation unit determines an opening and closing frequency for each orifice of a set of orifices among the orifices of the direct metering interface, as a function of a flow rate of carrier liquid in the first hydraulic circuit. The opening and closing frequency may in particular vary from one orifice to another, for greater precision of the metering at the nozzle.

[0024] According to one embodiment, the active product circulates in an injection direction and the carrier liquid circulates in a circulation direction during the injection of the active product into the carrier liquid, the injection direction of the active product being substantially parallel to the circulation direction of the carrier liquid, or forming with it an angle of between 0° and 90°.

[0025] Advantageously, the at least one spray nozzle comprises a nozzle head forming a chamber directly upstream of an outlet of the spray nozzle, and the injection section forms a circular portion housed in the chamber, and the spray assembly comprises a plurality of orifices distributed in a star shape on the injection section so as to inject active product into the nozzle head.

[0026] In this case, the mixing of the active product in the carrier liquid is even better and carried out directly in the nozzle head.

[0027] Advantageously, the spray assembly comprises a plurality of spray nozzles and one or more dosing interfaces dedicated to a spray nozzle or to a plurality of spray nozzles.

[0028] According to one embodiment, the spray assembly comprises an active product recirculation line extending between the at least one spray nozzle and the second reservoir to ensure continuous circulation of the active product in the spray assembly.

[0029] Advantageously, the spraying assembly comprises at least two second active product reservoirs connected respectively to corresponding second hydraulic circuits each having a direct dosing interface with the first hydraulic circuit. PRESENTATION OF FIGURES

[0030] The invention will be better understood on reading the following description, given solely by way of example, and referring to the appended drawings given by way of non-limiting examples, in which identical references are given to similar objects and in which:

[0031] [Fig.l] is a schematic representation of the spray assembly according to a first embodiment of the invention;

[0032] [Fig. 2] is a schematic representation of the spray assembly according to a first embodiment of the invention. It should be noted that the figures set out the invention in detail to enable the invention to be implemented, said figures of course being able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0033] The invention relates to a direct injection spray assembly. Such a spray assembly is shown schematically in [Fig. 1] and, according to another embodiment, in [Fig. 2].

[0034] The spraying assembly comprises a first tank comprising a carrier liquid, in particular water, and a second tank containing an active product, in particular a herbicide, a fungicide, an insecticide or a fertilizer. According to one embodiment, the spraying assembly comprises several second tanks. may contain different active products. In this case, said different active products can be dosed simultaneously in the carrier liquid.

[0035] The spray assembly according to the invention also comprises at least one spray nozzle 3, preferably a plurality of spray nozzles 3 distributed along a spray bar. For example, the spray bar is arranged in sections each comprising a set of spray nozzles 3 intended to be controlled in an identical manner.

[0036] Each of the first and second reservoirs is connected to the spray nozzles 3 via, respectively, a first hydraulic circuit 21 and a second hydraulic circuit 22. When there are several second reservoirs, in particular containing different active products, there are also several second hydraulic circuits 22, having a respective interface with the first hydraulic circuit 21.

[0037] Preferably, the first and second hydraulic circuits 21, 22 are closed circuits by means of recirculation lines, the first hydraulic circuit 21 looping back into the first reservoir and the second hydraulic circuit 22 looping back into the second reservoir.

[0038] The spraying assembly comprises in particular an injection device connected between the second hydraulic circuit 22 and an injection section 2 forming part of the first hydraulic circuit 21 and located directly upstream of the spraying nozzles 3.

[0039] The injection device is configured to inject active product into a flow of carrier liquid circulating in the first hydraulic circuit 21 from the first reservoir to the spray nozzles 3. To this end, the injection device comprises a direct metering interface 1 comprising one or more orifices to allow the injection of active product into the flow of carrier liquid circulating in the injection section 2 of the first hydraulic circuit 21.

[0040] The active product circulates in the second hydraulic circuit 22 under an injection pressure while the carrier liquid circulates in the first hydraulic circuit 21 under a circulation pressure lower than the injection pressure. Preferably, the injection pressure is at least one bar higher than the circulation pressure. For example, the injection pressure is 6 bars and the circulation pressure is 3 bars. In practice, the injection pressure is chosen according to the physicochemical properties of the product, in particular its viscosity.

[0041] According to the embodiment of [Fig. 1], the direction of circulation of the active product at the direct dosing interface 1 is substantially orthogonal to the direction of circulation of the carrier liquid. In this case, for the mixing to be most effective, the pressure difference between the injection pressure and the circulation pressure is preferably high, in particular greater than two bars, preferably greater than three bars.

[0042] According to the embodiment of [Fig. 2], the direction of circulation of the active product at the direct dosing interface 1 is substantially parallel to the direction of circulation of the carrier liquid. In this case, the pressure difference between the injection pressure and the circulation pressure may be lower, in particular of the order of one bar.

[0043] Thus, the angle formed between the main axis along which the active product circulates and the main axis along which the carrier liquid circulates, at the direct dosing interface, may in particular be between 0° and 90°. The closer the angle is to 0°, that is to say the direction of circulation of the active product at the direct dosing interface is substantially parallel to the direction of circulation of the carrier liquid, the easier it will be to inject active product into the carrier liquid.

[0044] The orifice(s) of the direct dosing interface 1 are holes, in particular substantially circular and capable of having a diameter of between 50 μm and 300 μm. According to one embodiment, if there are several orifices, the latter may have different diameters.

[0045] Each orifice is coupled to an actuator 4 controlled to open or close the passage of active product through said orifice. Preferably, an actuator 4 is coupled to a single orifice. Alternatively, an actuator 4 may be coupled to a group of orifices, simultaneously closing or opening all of the orifices of said group of orifices. In particular, each actuator is controlled in opening and closing by means of a pulse width modulation (PWM) generator so as to open and close each orifice at an opening and closing frequency.

[0046] According to one embodiment, a control unit 10 is configured to control the opening or closing of a number of orifices corresponding to a dosage instruction. Thus, depending on a desired dosage of active product corresponding to said dosage instruction, for example determined by a calculation unit configured for this purpose, the control unit 10 determines the number of orifices to be opened, the other orifices to be closed, so as to inject the desired quantity of active product into the carrier liquid, as well as the frequency of opening and closing of each orifice.

[0047] In particular, the dosage instruction may depend on various parameters that may vary individually or concomitantly, including the speed of the spraying system, the speed of the spraying nozzle in particular. The dosage instruction may be determined based on a modulation map of doses of active products to be applied, or based on calculations carried out on a recognition of the plants to be treated.

[0048] Depending moreover on the flow rate of active product requested in the second hydraulic circuit 22 and the flow rate of carrier liquid circulating in the first hydraulic circuit 21, the calculation unit 10 can determine a set of control signals for: alternately opening and closing a set of orifices among the orifices of the direct metering interface, the duration of the opening and the duration of the closing are variable for each spray nozzle 3.

[0049] For example, the control unit 10 determines a set of orifices and a frequency of alternating opening and closing of the orifices of the set of orifices. The desired quantity of active product is thus injected into the flow of carrier liquid, directly upstream of the spray nozzles 3.

[0050] Thus, by way of illustration, according to the invention, a calculation unit 10 can determine a dosage of active product to be sprayed, corresponding to a desired flow rate of active product at the outlet of the spray nozzle 3, in 1 / min. The desired flow rate of active product at the outlet of the nozzle corresponds to the dosage instruction.

[0051] Depending on the flow rate of carrier liquid conveyed to the spray nozzles 3, and depending, for example, on the speed of movement of the spray assembly, the control unit 10 determines the quantity of active product to be injected into the carrier liquid at the injection section 2, as a function of time.

[0052] For example, the control unit determines, as a function of the quantity of active product to be injected as a function of time, the number of orifices to be opened and / or the frequency of opening and closing of a set of orifices among the orifices of the direct dosing interface 1 and the duration of opening of the orifices. The control unit 10 then generates and transmits corresponding control signals to the actuators.

[0053] According to one embodiment, the direct dosing interface comprises at least 1 orifice, for example 32 orifices, in particular substantially circular and respectively having at least two different diameters from among the following diameters: 50 μm, 80 μm, 100 μm, 150 μm; 180 μm; 200 μm; 300 μm.

[0054] An advantage of having different sized orifices is the possibility of having a wider dosage range.

[0055] According to a particular embodiment, the spray nozzle(s) 3 of the spray assembly comprise a nozzle head forming a chamber directly upstream of an outlet of the spray nozzle 3 and the injection section 2 forms a circular portion housed in the chamber. Then, the orifices are distributed in a star shape on the injection section so as to inject active product into the nozzle head 3.

[0056] The actuators 4 are for example piezoelectric actuators. Alternatively, the actuators 4 may be pneumatic valve type controlled actuators. In this case, the spray assembly further comprises an air circuit compressed to ensure the opening and closing of the pneumo-valves.

[0057] One advantage of pneumo-valves is that the power of compressed air is used to close the pneumo-valve. There is no need to provide mechanical force for a spring-loaded closing system, for example, which could result in greater bulk.

[0058] According to another embodiment, the actuators 4 are solenoid valves. An advantage linked to the use of solenoid valves lies in the simplicity of their control. Solenoid valves are in fact directly controlled and do not require the prior opening of an air circuit, like pneumo-valves.

Claims

Claims

1. Spray assembly comprising a first reservoir configured to contain a carrier liquid, for example water, and a second reservoir configured to contain an active product, at least one spray nozzle (3), at least one injection device, a first hydraulic circuit (21) for conveying the carrier liquid from the first reservoir to the spray nozzle (3), under a carrier liquid circulation pressure, the first hydraulic circuit (21) comprising, upstream of the spray nozzle (3), an injection section (2), a second hydraulic circuit (22) for conveying the active product from the second reservoir to the injection device, under an injection pressure greater than the carrier liquid circulation pressure,the active product injection device being connected to the injection section (2) of the first hydraulic circuit (21) and being configured to inject the active product into a flow of carrier liquid circulating in the first hydraulic circuit (21), the injection device comprising, at the end of the second hydraulic circuit (22) opposite the second reservoir, a direct metering interface (1) comprising a plurality of through-orifices opening into the injection section (2) of the first hydraulic circuit (21), and the injection device comprising at least one actuator (4) corresponding to the plurality of orifices, configured to open or close the plurality of through-orifices, so as to allow a determined dosage of active product to pass through at least one open orifice among the plurality of through-orifices of the direct metering interface (1) to be injected into the flow of carrier liquid,so as to form a mixture composed of carrier liquid and metered active product intended to be sprayed via the at least one spray nozzle (3), for the purpose of treating crops.,

2. Spray assembly according to claim 1, wherein the at least one actuator (4) is a piezoelectric actuator.

3. A spray assembly according to claim 1, wherein the at least one actuator (4) is a pneumatic actuator and the spray assembly comprises a compressed air circuit for enabling actuation of the at least one pneumatic actuator.

4. A spray assembly according to claim 3, wherein the at least one actuator (4) is a piezoelectrically actuated pneumatic actuator.

5. A spray assembly according to claim 1, wherein the at least one actuator (4) is a solenoid valve.

6. Spray assembly according to one of the preceding claims, in which the at least one actuator (4) is controlled in opening and closing by a pulse width modulation generator.

7. Spray assembly according to one of the preceding claims, in which the injection pressure is at least one bar higher than the carrier liquid circulation pressure.

8. Spray assembly according to one of the preceding claims, in which the orifices of the plurality of orifices do not all have the same diameter, the different diameters of the orifices being in particular between 50 μm and 300 μm.

9. Spray assembly according to one of the preceding claims, comprising a plurality of orifices and a corresponding set of actuators, the spray assembly further comprising a calculation unit (10) for determining, from a dosing instruction, the quantity of active product to be injected into the flow of carrier liquid and for controlling the opening and closing of the corresponding number of orifices of the direct dosing interface (1).

10. Spray assembly according to the preceding claim, wherein the calculation unit (10) determines an opening and closing frequency for each orifice of a set of orifices among the orifices of the direct dosing interface (1), as a function of a flow rate of carrier liquid in the first hydraulic circuit.

11. Spray assembly according to one of the preceding claims, in which the active product circulates in an injection direction and the carrier liquid circulates in a circulation direction during the injection of the active product into the carrier liquid, the injection direction of the active product being substantially parallel to the circulation direction of the carrier liquid, or forming with it an angle of between 0° and 90°.

12. Spray assembly according to one of the preceding claims, in which the at least one spray nozzle (3) comprises a nozzle head forming a chamber directly upstream of an outlet of the spray nozzle (3), and the injection section (2) forms a circular portion housed in the chamber, and the spray assembly comprises a plurality of orifices distributed in a star shape on the injection section (2) so as to inject active product into the nozzle head.

13. Spray assembly according to one of the preceding claims, comprising a plurality of spray nozzles (3) and one or more dosing interfaces dedicated to a spray nozzle (3) or to a plurality of spray nozzles (3).

14. Spray assembly according to one of the preceding claims, comprising an active product recirculation line extending between the at least one spray nozzle (3) and the second reservoir to ensure continuous circulation of the active product in the spray assembly.

15. Spray assembly according to one of the preceding claims, comprising at least two second active product reservoirs connected respectively to corresponding second hydraulic circuits (22) each having a direct dosing interface (1) with the first hydraulic circuit (21).

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