FR3023495A1 - OPTIMIZATION OF A CARRIER AIR FLOW OUTSIDE A SPRAY GUN - Google Patents

Abstract

The present invention provides a jet spray gun (2) carried by an air flow (4) comprising a tank (10) adapted to contain a liquid, a diffuser tube (8) comprising an inlet (26), an outlet 28), having a longitudinal axis (A-A '), a core (30) axially symmetrical along an axis (B-B'), at least one nozzle (38) adapted for spraying liquid, the core ( 30) has a first end (32) of ogival and a second end (34) truncated, the first end (32) being on the side of the inlet (26) and the second end (34) on the outlet side (28). ), the core (30) has an average outer radius substantially equal to two-thirds of the inner radius (R) of the tube (8), the second end (34) is outside the tube (8) at a predetermined distance from at the outlet (28), the nozzle (38) is adapted to spray liquid at the second axial end (34) of the core (30).

Description

FIELD OF THE INVENTION The present invention relates generally to the optimization of a carrier air flow at the outlet of a jet spray gun. by a flow of air. It finds applications, in particular, in the field of crop protection or vector control in natural areas. Technological background The treatment and protection of crops is a major issue for the agricultural sector. Indeed, since the advent of intensive culture techniques, the use of treatment products is increasingly important. As a result, it is necessary today to consider the impact of these treatments on the environment and bio-diversity. Various devices for spraying treatment products on cultivated areas have appeared in recent years. The selection of these devices generally depends on the type of crop and / or the surface of the area to be treated (vegetation or surface water). Spray guns are the most used treatment devices and there are different types of spray gun for crop protection (fungicide or insecticide treatment). In these devices, a liquid preparation (slurry) is broken up into droplets which are injected into a stream of air. The droplets are then transported at high speed by the airflow so that they are deposited over a distance as large as possible. The principle of these devices is to generate a cloud of droplets on a given area, covered with crops for example, such as a plantation.

The document FR 7026477 shows an example of a spray gun comprising a tube, a warhead placed in the tube, and blades positioned at an angle of 150 relative to the tube for guiding a liquid treatment product on the ogive. A device for generating an air flow is coupled to the tube. A jet of liquid is sprayed, at the level of the warhead by the air flow that passes through the barrel and is carried by the air flow on the area to be treated up to a certain distance from the exit of the barrel spray. The treatment distances of such a device remain relatively low and the homogeneity of the treatment liquid drops transported on the treated area is relatively poor, forcing the operator to make several cross passages to ensure that the entire area is treated properly. SUMMARY OF THE INVENTION The object of the invention is to provide a device making it possible to improve the efficiency of a spray gun, namely on the one hand to improve the spray distance covered by the jet carried and on the other hand to improve the homogeneity of the distribution of the droplets of treatment product over a given area. For this purpose, according to a first aspect of the invention, there is provided a jet spray gun carried by an air flow comprising: - a tank adapted to contain a liquid, - a diffuser tube comprising an inlet, an outlet , having a longitudinal axis, a length along the longitudinal axis and an inner radius, - air propulsion means adapted to generate the flow of air entering through the inlet of the diffuser tube and out through the outlet of said diffuser tube outwardly, an ovoidally shaped core having axial symmetry along an axis, fixedly arranged partly in the diffuser tube, so that the axis of symmetry of the core corresponds to the longitudinal axis of the diffuser tube; at least one nozzle adapted to spray liquid present in the tank, wherein: - the core has a first axial end ogive and a second axial end truncated in a plane perpendicular to the outlet of the tube diffu the first axial end being on the side of the inlet of the diffuser tube and the second axial end being on the outlet side of said diffuser tube, the core has an average outer radius substantially equal to two thirds of the inner radius of the tube; second axial end of the core is outside the tube at a predetermined distance from the outlet of the diffuser tube, the nozzle is adapted to spray liquid present in the tank at the second axial end of the core.

Thus, the spray efficiency of the spray gun is increased. In order to improve the performance of the air-jet spray gun and in particular the speed of the air flow therethrough, the core may have an outer radius equal to two-thirds of the radius of the tube, thus making it possible to have a sectional ratio between the tube and the core of the order of two. Advantageously, in order to obtain a tubular air flow at the outlet of the tube, the core may have an axial half-length equal to twice the radius of the diffuser tube. To obtain a substantially tubular air flow at the outlet of the tube, the core may have a radius of curvature substantially equal to ten thirds of the radius of the diffuser tube. Thus, thanks to the tubular air flow propagating around the core, a protected zone is created at the second axial end of the core. The largest outer radius of the core may be at a distance from each of the first and second axial ends of the core corresponding to half a length of the core along the longitudinal axis of said core. With such an arrangement, the air flow created is a high-speed air flow which contributes to the desired efficiency. Advantageously, the largest outer radius of the core is in a plane outside the tube at a distance from the plane of the outlet of the tube substantially equal to half the inner radius of the diffuser tube. Thus, the airflow is not detached from the core. In order to maintain the core in the center of the tube reliably, the core is held in the tube with fins that can be for example three in number, the fins bearing on the inner surface of the diffuser tube and limiting the passage section of the air flow in the tube to the strict minimum. In an advantageous embodiment, the axial nozzle may be positioned in the core on the axis of symmetry of said core, so as to spray liquid along the longitudinal axis of the diffuser tube. Thus, the drops are transported by the airflow at high speed which improves the efficiency of the spray gun. In an alternative embodiment, the nozzle is disposed outside the core at the second axial end of the core, so as to spray liquid towards the longitudinal axis of the diffuser tube.

In order to improve the distribution of the drops on the treated area, the nozzle can generate a jet having a tubular shape. Brief Description of the Drawings Other features and advantages of the invention will become apparent upon reading the following description. This is purely illustrative and should be read with reference to the accompanying drawings in which: - Figure 1 is a perspective view of a spray gun according to the invention; FIG. 2 is an enlarged perspective view of the airflow optimization device of FIG. 1; - Figure 3 is a simplified sectional view of the core; - Figure 4 is an enlarged perspective view of the invention according to another embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS FIG. 1 shows an exemplary embodiment of a jet spray gun 2 carried by a stream of air 4. The spray gun 2 comprises among other things a diffuser tube 8, a tank 10 and means for propelling air. In Figure 1, the spray gun 2 is shown in a so-called "towed" configuration. Thus, it is mounted on a frame 12 comprising at least one axle with wheels 14 and connecting means adapted to couple the frame 12 to an agricultural implement (not shown in the figures). In order to increase the service life of the chassis it can be galvanized. The agricultural apparatus may be an agricultural tractor or other type of agricultural machine adapted to operate the spray gun 2 according to the present invention. Other vehicles, such as a pickup truck or a quad can also be used. The machine used may include a training device such as a PTO. In another embodiment, the spray gun 6 may be in a configuration called "scope" (not shown in the figures). Thus, the machine used will carry the spray gun 2. It should be noted that depending on the configuration, that is to say "towed" or "range", the frame 12 may not include axle and / or wheels 14. The frame 12 is adapted to receive and support the tank 10. It has a specific capacity and is preferably made of compatible material with products used to treat fruit plantations, for example. It can also be treated against ultraviolet rays. The tank 10 also has an opening 16 adapted to allow access to the tank 10 to allow for example its filling. The opening 16 may also have a plug adapted to close the access to the tank 10 during the processing phases. The treatment products contained in the tank 10 may be, for example, fungicides, pesticides or products intended for larviciding vector control. The tank 10 further comprises at least one pipe 18 adapted to convey the treatment products contained in the tank 10 to distribution means. These distribution means will be presented later in the description. In order to suck the products contained in the tank 10 and to circulate them in the pipe 18, pumping means can be used. These pumping means (not shown in the figures) can be actuated by the machine such as for example by the power take-off of the tractor or by an independent electric motor installed on the frame 12.

The air propulsion means shown in FIG. 1 are composed of a turbine 20. In one exemplary embodiment, the turbine 20 has a PTO inlet (not visible in the figures) adapted to be coupled to the intake force of the agricultural machine. Thus, when the PTO of the agricultural machine is actuated, the turbine 20 is activated and generates the air flow 4.

The turbine 20 further comprises a turbine outlet 22 adapted to concentrate and deliver the air flow 4. Advantageously, the use of the turbine 20 makes it possible to control with relative precision the speed of the air flow 4. an exemplary embodiment of the invention, the speed of the air flow 4 generated by the turbine 20 is greater than 20m / s.

Other means of air propulsion can also be used. Thus, for example, the air flow 4 can be generated using a helical type fan or even centrifugal. The fan can be coupled to suitable means for concentrating the flow of air 4.

In order to conduct the air flow 4 generated by the turbine 20 to the diffuser tube 8, a vertical duct 24 is used. It has dimensions and shapes adapted to allow the flow of air 4 generated by the turbine 20 to be injected into an inlet 26 of the diffuser tube 8. The vertical duct 24 can be in an embodiment of synthetic plastic and flexible according to the height of the plantations to be treated. The diffuser tube 8 has an outlet 28. It furthermore has an axial symmetry along an axis of symmetry A-A '(FIG. 1). The inlet 26 is adapted to be coupled to the vertical duct 24 thus making it possible to receive the flow of air 4 generated by the turbine 20. The outlet 28 is adapted to propel the air flow 4 which passes through the diffuser tube 8 towards the 'outside. In an exemplary embodiment, the diffuser tube 8 is fixed by fixing means (not shown in the figures) to the frame 12. In another embodiment, the diffuser tube 8 can be fixed to the tank 10. Thus, the device 2 is protected from the vibrations generated by the operation of the agricultural machine, which allows an improvement in the service life of the device 2. The diffuser tube 8 has a determined length L and an internal radius R determined. The length L and the internal radius R of the diffuser tube 8 are calculated so that the air flow 4 at the outlet thereof is preferably in a laminar flow regime. Other characteristics of the air flow 4 at the outlet of the diffuser tube 8 will be presented later in the description. The diffuser tube 8 is made of a material adapted to resist splashes of products. For example, it may be synthetic plastic material. In addition, it has a thickness adapted to be able to withstand the mechanical stresses generated by the passage of the air flow 4. In one exemplary embodiment, the diffuser tube 8 has on an outer part fixing means (not shown in FIGS. ) adapted to maintain the pipe 18 from the tank 10. The fastening means may be for example clip clamps.

Preferably, the diffuser tube 8 is in a position substantially parallel to the ground. Thus, the air flow 4 at the outlet of the diffuser tube 8 arrives perpendicularly to the fruit trees to be treated, which substantially improves the penetration power of the treatment product in the branches.

In another embodiment, the diffuser tube 8 is placed at a height greater than the plantations, for example during the treatment of tobacco plants. Thus, the propagation of the processing cloud is improved. In order to preserve natural resources but also to reduce the costs of treating farms, the device 2 proposed here optimizes the air flow 4 at the outlet of the tube 8 diffuser. Thus, the scope of the spray gun 2 is improved and the distribution of drops of the treatment products is more homogeneous on the area to be treated. To do this, it is proposed to have a fixed part of the tube 8 diffuser, so that the axis of symmetry (B-B ') of the core 30 corresponds to the longitudinal axis (A-A') of tube 8 diffuser. Preferably, the core 30 has an ovoid shaped warhead. FIG. 2 shows an enlarged view of the spray diffuser tube 8 comprising the core 30 and FIG. 3 shows a simplified and enlarged half-view of the core 30. For the sake of brevity and clarity of the description, all The dimensions that will follow in the description will be referenced (FIG. 3) with respect to an abscissa axis (x) and an ordinate axis (y); the ordinate axis intersecting the abscissa axis at a point named point of origin O. The core 30 has an axial symmetry along the axis BB 'positioned on the abscissa axis (x), a length L and an outer radius r. It also has a first axial end 32 positioned on the origin point 0 and a second end 34 axial. The second axial end 34 is spaced from the first axial end 32 by the distance L which corresponds to the length of the core 30. Advantageously, the outer radius of the core 30 at the first axial end 32 is zero. The value of the outer radius of the core 30 increases progressively up to a maximum value equal to 2 / 3R (where R is the internal radius of the diffuser tube 8). This value is reached at a distance equal to 2R with respect to the origin point 0 (FIG. 3). This characteristic point of the core 30 will be named in the following half-length description of the core 30.

Then, the outer radius of the core 30 decreases to a value equal to 2 / 6R. As shown in FIG. 3, the core 30 is not symmetrical along its length. The core 30 further has a radius of curvature equal to 10 / 3R and a mean radius substantially equal to 2 / 3R. In an exemplary embodiment, the core 30 may be made of plastic synthetic material. To modify the air flow 4 at the outlet 28, the core 30 is positioned in the diffuser tube 8 so that the axis of symmetry BB 'of the core 30 corresponds to the axis of symmetry AA' of the tube 8 diffuser, and is disposed at least partially in the tube 8 diffuser fixed manner (Figure 2). In an exemplary embodiment, the portion of the core 30 inserted into the diffuser tube 8 is approximately equal to 2 / 3R (FIG. 2). Advantageously, the first axial end 32 of the core 30 is on the side of the inlet 26 of the diffuser tube 8 and the second axial end 34 of the core 30 is on the side of the outlet of the diffuser tube 8. In an advantageous embodiment, the second axial end 34 of the core 30 is outside the diffuser tube 8 at a determined distance from the outlet 28 of said diffuser tube 8. In addition, the second axial end 34 is truncated in a plane perpendicular to the outlet 28 of the diffuser tube, to create a zone P1 said protected area at the second end 34 axial (Figure 3). Advantageously, at this protected area Pi, the speed of the air flow is zero. Thus, thanks to the core 30 positioned in the diffuser tube 8, the air flow 4 at the outlet 28 of the diffuser tube 8 is focused and concentrated. In addition, thanks to such a device, no air separation is present on the surface of the core 30 except at its second axial end 34 corresponding to the protected area P1 which allows to control both the laminarity air flow 4 at the outlet 28 of the diffuser tube 8 and the air velocity. The presence of the core 30 in the diffuser tube 8 thus makes it possible to create a high-speed tubular air flow 4. The core 30 is held in the diffuser tube 8 by means of fixing means. These fixing means comprise for example fins 36 and can be three in number. Advantageously, the fins 36 are evenly distributed around the core 30 so as not to disturb too much the flow regime of the air in the diffuser tube 8 but also around the core 30. In one exemplary embodiment, the fins 36 are profiled .

The fins 36, the core 30 and the diffuser tube 8 can be made in a common unit. For example, they can be made using a thermo molding process. Thus, the manufacturing cost of such a device is relatively low.

In another embodiment, the diffuser tube 8, the core 30 and the fins 36 are manufactured independently and are assembled using suitable means such as rivets or clamping screws. In an exemplary embodiment, for a speed of the air flow 4 at the inlet 26 of the diffuser tube 8 of the order of 50 m / s and for an internal radius of the diffuser tube 8 of the order of 60 mm (1 mm = 0, 6m), the speed of the air flow 4 obtained at the outlet 28 of the diffuser tube 8 is of the order of 100 m / s. Thus, thanks to such a device, it is possible to obtain a mutilator factor of two between the speed of the air flow 4 at the inlet and that of the outlet of the diffuser tube 8.

In an exemplary embodiment, a recess is made in the center of the core 30 (Figure 3). This recess can be made over the entire length L of the core 30. It has a radius adapted to accommodate at least one nozzle 38 and the pipe 18 from the tank 10 to supply the nozzle 38 in treatment liquid . The nozzle 38 is coupled to the pipe 18 and is adapted to spray liquid present in the tank 10 at the second axial end 34 of the core 30. It has an outside diameter adapted to allow its insertion into the core 30. The nozzle 30 may be attached to the core 30 either by a recess connection or by suitable fastening means.

In an exemplary embodiment, the nozzle 38 has a sufficient and adjustable flow diameter. Preferably, the nozzle 38 generates a stream of conical shape with an angle of the order of 30 °. In an exemplary embodiment, the nozzle 38 has a liquid ejection speed of the order of 20m / s. Advantageously, thanks to its positioning in the center of the core 30, the nozzle 38 ejects its jet of treatment liquid in the protected area Pi. Thus, secondary fragmentation phenomena are reduced to control the size of the drops of liquid. By controlling the size of the drops of liquid and the positioning of the nozzle 38 in the protected area Pi, the products are sprayed homogeneously over the areas to be treated, which makes it possible to significantly reduce the losses. In addition, thanks to the fragmentation of the liquid in the high-speed air flow, the drops are propagated outside the barrel at a very high speed, which significantly increases the range of the spray gun.

Advantageously, thanks to the spray gun 2 according to the invention, the plantations located in the treated area receive a similar amount of treatment product and this regardless of the position of the fruit tree on the treated area which allows to reduce the number passages and, above all, to avoid passing overlays. FIG. 4 shows another exemplary embodiment of the invention in which at least one nozzle 40 is used for diffusing treatment liquid in the protected zone Pi. The nozzle 40 can be disposed outside the core 30 at the level of the second axial end 34 of the core 30, so as to spray liquid towards the longitudinal axis of the diffuser tube 8. The nozzle 40 is coupled to the pipe 18 thus making it possible to supply said nozzle 40 with treatment product. In an exemplary embodiment, the nozzle 40 has the same characteristics as the nozzle 38 shown above. Thus, thanks to the positioning and the characteristics of the nozzle 40, the drops of liquid are projected at a greater distance than the coreless treatment devices. Thus, a carrier spray gun 2 using the core 30 has its spray range increased by about 20%. The range can be improved by a distance of the order of two meters to reduce the number of passages and thus reduce the cost of treatment per hectare.

In another embodiment of the invention, the number of nozzles 40 may be greater than one. Thus, for example, the number of nozzles 40 may be three, which makes it possible to increase the dose of treatment product in the air stream 4 sprayed by the spray gun 2. Also, in another example embodiment of the invention, the invention or the nozzles 40 can be coupled to the nozzle 38. Thus, for example, it is possible to diffuse in the protected area P1 several treatment products simultaneously which allows an optimization of the treatment and a reduction in the cost of treatment per hectare. In another embodiment, several diffuser tubes 8 comprising the core 30 can be used. Thus, the area of the treated area is increased, which makes it possible to improve the treatment cost per hectare. The present invention thus makes it possible to produce a jet spray gun. Thus, it is proposed a device intended in particular to optimize the distance and the distribution of drops of products on plantations. The present invention is not limited to the embodiments described above by way of non-limiting examples and the shapes shown in the drawing and the other variants mentioned but it relates to all embodiments within the reach of the skilled person within the scope of the claims below.

Claims (10)

REVENDICATIONS1. Air-blast spray gun (2) (4) comprising: a tank (10) adapted to hold a liquid, a diffuser tube (8) comprising an inlet (26), an outlet (28), having a longitudinal axis (A-A '), a length (L) along the longitudinal axis and an inner radius (R), air propulsion means adapted to generate the air flow (4) entering through the inlet (26) of the diffuser tube (8) and exiting through the outlet (28) of said diffuser tube (8) to the outside, an ovoid-shaped core (30) having an axial symmetry along an axis (B-B ' ), arranged in a fixed manner partly in the diffuser tube (8), so that the axis of symmetry (B-B ') of the core (30) corresponds to the longitudinal axis (A-A') of the diffuser tube (8), at least one nozzle (38) adapted for spraying liquid present in the vessel (10), wherein: the core (30) has an axial first end (32) and a second axial end (34) truncated in a p lan perpendicular to the outlet (28) of the tube (8) diffuser, the first end (32) being axial on the side of the inlet (26) of the tube (8) diffuser and the second end (34) axial being on the side of the outlet (28) of said diffuser tube (8), the core (30) has an average outer radius substantially equal to two-thirds of the inner radius (R) of the tube (8), the second axial end (34) of the core (30) ) is outside the tube (8) at a determined distance from the outlet (28) of the diffuser tube (8), the nozzle (38) is adapted to spray liquid present in the tank (10) at the level of the second axial end (34) of the core (30). 2. spray gun (2) according to claim 1, wherein the outer radius of the core (30) is equal to two-thirds of the inner radius (R) of the diffuser tube (8). 3. spray gun (2) according to one of claims 1 and 2, wherein the core (30) has an axial half-length equal to twice the radius (R) of the tube (8) diffuser. 4. Spray gun (2) according to one of claims 1 to 3, wherein the core (30) has a radius of curvature substantially equal to ten thirds of the inner radius (R) of the tube (8) diffuser. The spray gun (2) according to one of claims 1 to 4, wherein the largest outer radius of the core (30) is at a distance from each of the first and second axial ends of the core corresponding to one half. length of the core along the longitudinal axis of said core. The spray gun (2) according to one of claims 1 to 5, wherein the largest outer radius of the core (30) is in a plane outside the tube (8) at a distance from the plane of the outlet of the tube substantially equal to half the inner radius (R) of the tube (8) diffuser. The spray gun (2) according to one of claims 1 to 6, wherein the core (30) is held in the diffuser tube (8) by means of fins (36) extending from the internal wall of the diffuser tube. Spray barrel (2) according to one of claims 1 to 7, wherein the nozzle (38) is arranged in the core (30) on the axis of symmetry of said core, so as to spray the following liquid. the longitudinal axis of the diffuser tube. Spray barrel (2) according to one of claims 1 to 8, wherein the nozzle (40) is disposed outside the core at the second axial end (34) of the core (30), in order to spray liquid towards the longitudinal axis of the diffuser tube. 10. spray gun (2) according to one of claims 1 to 9, wherein the nozzle (38, 40) is adapted to generate a tubular shaped jet.