FR3139737A1 - Device for spraying ozonated water in an agricultural environment - Google Patents

Abstract

The invention relates to a device for spraying ozonated water in an agricultural environment, the device comprising a collar defining a distribution opening (4) for the joint distribution of water and ozone, the water being sprayed by a nozzle ( 10) set back from the opening, the nozzle being supplied by a tank (7) on board with the device, the gaseous ozone being distributed by a gas inlet (22) connected to a gas production and/or storage device (9, 13) also on board with the device, the gas inlet also being recessed in the collar, such that the collar defines a confinement chamber (28, 29) of the gaseous ozone emitted around the sprayed liquid in order to allow enrichment of the sprayed liquid with dissolved ozone. Figure for abstract: Figure 6

Description

Ozonated water spraying device in agricultural environment

The present invention relates to a spraying device, in particular intended to be used in the open air, outdoors, in particular in an agricultural environment, on hectares of crops to be treated, or indoors. The interest of the invention is to be able to spray a liquid loaded with gas or gaseous solute, while limiting the desorption of the gaseous solute or gas from the sprayed liquid. This device can more particularly spray water loaded with ozone via a nozzle, in order to carry out a treatment whether it is of the phytosanitary type for crops or of the chemical type for an action on a surface to be treated.

Technological background

In the state of the art, ozonated water diffusion devices are known for sterilization, disinfection and deodorization in industrial environments and in closed environments with a controlled atmosphere. In particular, documents US5431861, US6,076,748 or JP2008229491 describe such devices.

On an experimental scale, ozonated water is known for its effectiveness in combating the development of certain pathogens. Ozonated water could be an alternative to phytosanitary treatments based on synthetic products from the chemical industry. Indeed, ozonated water has a major ecological advantage in that the persistence of the ozone molecule is very low, and decomposes into environmentally neutral dioxygen.

However, since the half-life of gaseous ozone in air at 20°C is 3 days, while the half-life of ozone dissolved in water at 20°C is 20 min, ozonated water has never been able to be used effectively in an agricultural environment to carry out phytosanitary treatments. Indeed, in the open air, it is not possible to force gaseous ozone to remain in contact with the crops to be treated, due to climatic hazards and wind. In addition, the solubilization of ozone in the aqueous phase reduces the half-life of ozone to a duration of around 20 minutes at room temperature and remains problematic. Indeed, spraying ozonated water through a nozzle towards a target to be treated is associated with a strong desorption of ozone in the sprayed droplets, making this action ineffective.

The object of the invention is to propose a solution that is adaptable to the agricultural environment and whose efficiency is demonstrated in the phytosanitary treatment of the plants concerned. The interest of the invention is to propose a technical solution that makes it possible to maintain an effective ozone concentration in a sprayed liquid either by promoting the absorption of ozone in this liquid or by limiting its desorption.

The interest of the invention is to allow a spraying of a liquid in a gaseous environment in order to increase the absorption of the gaseous solute or to limit its desorption. These spraying conditions correspond to a difference in speed between the ejected liquid and the gas diffused around the ejected liquid, causing friction occurring on the surface of the ejected liquid. This friction induces the transformation of the liquid jet in the form of a liquid film into ribbons, then into ligaments which then break into relatively spherical particles in order to produce a cloud of drops.

The invention consists in promoting the dissolution of the gas in the form of a gaseous solute in the ejected liquid, in particular at the time when the liquid is still predominantly in the form of a jet, film or ligaments, and before the majority of the liquid is in the form of drops. The invention also aims to limit desorption of the gaseous solute (Ozone) already dissolved in the ejected liquid, in particular when this liquid is still predominantly in the form of a jet, film or ligament. The invention also consists in limiting the presence of gas other than that of the gaseous solute around the liquid when the liquid is still predominantly in the form of a jet, film or ligaments. The invention promotes the presence of gas around the liquid sprayed in the form of a jet, film or ligaments, in order to increase the proportion of gaseous solute of this gas in the liquid.

The invention relates to a spraying device, in particular for spraying ozonated water in an agricultural environment, the device comprising
- a joint liquid and gas distribution opening,

- a nozzle intended to be connected to a tank of liquid to be sprayed,
- a gas inlet from a gas production and/or storage device,
and a collar surrounding the nozzle and the gas inlet, such that an edge of this collar defines the dispensing opening of the device, and that a spray orifice of the nozzle is at a setback distance (dr) in the collar relative to this dispensing opening, the collar defining a containment chamber for the gas emitted by the gas inlet, the containment chamber extending between the spray orifice and the dispensing opening.

In particular, a difference in the liquid emission speed from the spray orifice is between 50 and 1500 times, preferably between 100 and 300 times, greater than a gas distribution speed from the gas inlet, so that the liquid can be predominantly in the form of a jet, film or ligaments in the collar. In particular, a liquid distribution speed is of the order of 5 to 15 m/s while a gas distribution speed is of the order of 1 to 10 cm/s.

Preferably, the spray orifice can distribute the liquid according to a spray distributed spatially in at least one plane, such that a width of the opening measured in this plane and orthogonally to a spray axis Y of the nozzle represents between 80% and 140%, and more particularly between 95% and 120% of a spray width in this same plane for a spray produced by said nozzle without its collar, this spray width being measured at a distance from the spray orifice equal to the withdrawal distance.

More particularly, the spray orifice can distribute the liquid according to a spray distributed spatially in at least one plane and having a spray thickness transverse to this plane such that a thickness of the opening measured transverse to this plane represents more than 100% and less than 140% of the spray thickness transverse to this same plane for a spray produced by said nozzle devoid of its collar, the spray thickness being measured at a distance from the spray orifice equal to the withdrawal distance.

Advantageously, the spray orifice can distribute the liquid in a spray comprising a portion in the form of a liquid film having a continuous surface such that a length of the continuous surface of this film measured along a spray axis of the nozzle represents between 40 and 120% of the withdrawal distance.

In particular, the spray orifice may be in the form of a longitudinal slot along an elongation axis Z, and in this case the distribution opening of the device preferably has a main elongation axis parallel to the axis of the slot.

In particular, the gas inlet may be arranged set back from the spray orifice relative to the dispensing opening. Such a configuration makes it possible to avoid the formation of turbulence at the spray orifice, the gas then being able to be dispensed in an annular volume and diffuse in an annular manner around the nozzle.

In particular, for homogeneous diffusion of the gas in the confinement chamber, the device may include at least two equally distributed gas inlets, either diametrically opposed when there are only two inlets, and for example supplied with an identical gas sourced by the same gas production and/or storage device.

Preferably, the volume of the containment chamber may be parallelepipedal.

The interest of the invention is to propose a collar that makes it possible to define a containment chamber. De facto, the configuration of the nozzle and the collar are jointly determined so that the spray orifice sprays a spray whose nominal volume of the envelope surface of this spray, inside the collar, represents a volume less than 5% of the internal volume of the collar.

Advantageously, the distribution opening is unique, and the collar is formed by a continuous wall, so that all gases and liquids contained in the containment chamber can be controlled.

The invention also relates to a method of designing a spraying device in which
- a nozzle is selected capable of emitting a liquid spray distributed spatially according to an opening angle in a plane and a radial thickness transversely to this plane,
- a liquid flow rate from the nozzle is determined, in order to determine a gas flow rate as a function of this liquid flow rate,
- a collar depth is determined based on the opening angle and the radial thickness of the nozzle spray.

The invention also relates to an assembly for treatment with a solute dissolved in a liquid comprising a spraying device according to the invention, a reservoir of liquid to be sprayed, the same device for producing and/or storing the gas of interest to be diffused jointly with the liquid by the spraying device, the device for producing and/or storing gas comprising a bypass towards the reservoir to enrich the liquid contained in the reservoir with gaseous solute, such that the liquid can comprise a non-zero proportion of dissolved gaseous solute before it is sprayed.

Brief description of the figures

The following description, with reference to the attached drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented. In the attached figures:

There represents a diagram of agricultural spraying of a phytosanitary treatment on a vine, in which a spraying by a cloud of drops is schematized, and a proportion of gas in this cloud of drops is also schematically represented by a density of black dots in each drop;

There represents a first device for modeling the distribution of a liquid comprising a proportion of dissolved gas;

There represents a graph with measured proportions of dissolved gas in the liquid distributed by a device according to the , depending on a distance between the measuring point and a spray orifice of this liquid by a nozzle of the device according to the ;

There represents a view of a spray diffused by a nozzle of a spraying device according to the invention

There represents a view of the spray of the according to a viewing angle perpendicular to that of the ;

There represents a second device for modeling the distribution of a liquid comprising a proportion of dissolved gas according to a spraying device according to the invention;

There represents a graph with measured proportions of dissolved gas in the liquid distributed by a device according to the , depending on a distance between the measuring point and a spray orifice of this liquid by a nozzle of the device according to the ;

There represents a perspective view of a spraying device according to the invention;

There represents a longitudinal sectional view of a spraying device according to the ;

There represents a perspective view of a spraying device according to an alternative embodiment of the invention;

There represents a longitudinal sectional view of a spraying device according to the ;

There represents a perspective view according to a partial longitudinal section of a spraying device according to the .

Description of embodiment(s)

In the figures, and unless otherwise specified, identical elements will bear the same reference signs.

In the agricultural environment, as shown in the , an agricultural sprayer 1 is generally a mobile device. Since crops are organized to facilitate the mechanization of agricultural work, the agricultural sprayer 1 is provided with means of movement 2, such as wheels 2 in the example of the , in order to facilitate the movement of the sprayer along a plantation 3 to be treated. In particular, the agricultural sprayer 1 is towed along furrows each carrying plantations, such as vines, to be treated. The agricultural sprayer 1 is intended to disperse a phytosanitary treatment, preferably in a homogeneous dose during its movement along the crops.

To preserve the crops, the sprayer is kept at a distance from these crops during its movement, such that a distance "d" between a distribution opening 4 of the device 1 and a foot 5 of the plantation 3, measured transversely to the axis of movement of the device 1, is preferably greater than the value d reduced by half of a theoretical width l _th average of the plantation 3, this theoretical width being measured transversely to the axis of movement of the device 1. A distribution axis Y of the sprayer 1 is oriented perpendicular to a rolling direction X of this sprayer 1. The spraying is lateral to the movement.

To ensure the homogeneity of the deposit of the phytosanitary treatment, the agricultural sprayer is configured to ensure the formation of a cloud of drops 6 whose drops will mainly be propelled up to a distance whose value will be between [ d – ½* l_{th ;}d + ½* l_th ]. At this distance, the lateral propulsion force of the drops is cancelled out by the weight of these drops, which will settle by gravity on the plantation 3. The agricultural sprayer 1 may include means for orienting the distribution opening 4 so that the distribution axis Y can be modified, and not necessarily be oriented parallel to the ground on which the wheels are resting.

The sprayer 1 is intended to allow a joint distribution of liquid and gas, and also of gas dissolved in the liquid. The sprayer 1 comprises a first means of connection to a liquid tank 7. This liquid tank 7 can be supported by a chassis 8 on which the wheels 2 are mounted. The sprayer 1 comprises a second means of connection to be connected to a gas production and/or storage device 9, this device being able to be a gas cylinder, in which the gas is compressed. The gas production and/or storage device 9 is also carried by the chassis 8.

The liquid tank 7 contains water, or ozonated water having a non-zero proportion of ozone. The gas cylinder 9 contains gaseous ozone. Under ambient conditions, ozone tends to decompose naturally into dioxygen.

There represents a device for modeling a proportion of ozone (O3) in a liquid film 11 sprayed by a device for preparing ozonated water and spraying by a nozzle 10, the ozone already being dissolved in the liquid intended to be sprayed. In this modeling, the nozzle 10 is supplied by a connection means 12 to a reservoir 7 of liquid, in particular water. This reservoir 7 is itself supplied by a pipe 18 with gas supplied by an ozone generator 13. The ozone generator 13 can enrich the liquid with ozone continuously, in order to control and maintain a proportion P1 of ozone dissolved in the liquid to be sprayed by the nozzle.

There represents an evolution of the proportion P2 of ozone dissolved in the film 11, this proportion P2 is a function of a distance D of distance of the measurement relative to the nozzle 10 along a distribution axis Y. This modeling confirms the observations concerning the inefficiency of a treatment with sprayed ozonated water insofar as from the first centimeters at the exit of a spray orifice 14 of the nozzle 10, a very clear drop in the proportion of dissolved ozone is observed in the film 11. And at the distance D of 1 meter, the proportion P2 of ozone dissolved in the distributed liquid is divided by 20 compared to the proportion P1 of ozone dissolved in the liquid of the tank 7.

Preferably, to obtain a film, the nozzle 10 comprises a spray orifice 14 in the form of a longitudinal slit along an axis Z, so that the jet is in the form of a film whose contours projected onto a plane containing the axis Z comprise a continuous surface 15 originating from the slit of the spray orifice, this continuous surface 15 being bordered by filaments 16 which end in drops 17. The continuous surface 15 forms a liquid film 15. As shown in FIG. , which is a view perpendicular to that of the , it is observed that the continuous surface 15 is substantially flat over a distance D1 measured from the spray orifice 14, and then undulates over a distance D2, to be predominantly in the state of drops 17 beyond the distance D2.

The cloud of drops is thus formed at a cumulative distance of D1 and D2 from the spray orifice 14. There is thus a continuous liquid film over a cumulative distance of D1 and D2. Over the distance D1, a thickness “e” of the film is represented . This thickness e decreases as the distance from the spray orifice 14 at which the thickness is measured increases. The further the measurement is made from the spray orifice, the lower the thickness of the film. In fact, the continuous surface 15 becomes thinner until it forms the filaments 16 and the drops 17.

The envelope surface of the spray sprayed by the spray orifice 14 encompasses the spatial environment in which the continuous surface 15, the filaments 16 and the drops 17 are located at the outlet of the spray orifice. Depending on the spray direction Y relative to the ground, the shape of this envelope surface changes under the effect of the gravitational forces which apply to the drops.

On the , the spray orifice distributes the liquid according to a spray having an opening angle α. The peak of the opening angle α is located upstream of the spray orifice 14. In view of the observation that from the first centimeters at the outlet of the spray orifice 14 of the nozzle 10, a very clear drop in the proportion of dissolved ozone was observed in the film 11, the inventors have demonstrated that this phenomenon could be circumscribed, and at least limited by the presence of a collar 20 around the sprayed liquid, this collar being arranged around the sprayed liquid from the first centimeters around the outlet of the spray orifice.

There represents a modeling of a spraying device according to the invention. According to the invention, the spraying device 1, also called a sprayer, comprises a nozzle 10 intended to be connected to a reservoir 7 by a connection 12. The nozzle is intended to distribute a liquid contained in the reservoir 7 through a spray orifice 14. In particular, according to one embodiment, the liquid is sprayed in the form of a film 11. In the invention, the device comprises a collar 20 which surrounds the nozzle 10 and the spray orifice 14 such that an edge 21 of this collar 20 delimits an opening 4 of the spraying device.

According to the invention, the sprayer according to the invention 1 also comprises a gas inlet 22, this inlet 22 being connected to a pipe 23 to be connected to a gas generator 13 or a gas bottle 9. Preferably the gas is compressed in the gas bottle 9. The gas inlet 22 is arranged inside the volume delimited by the collar 20.

The collar 20 comprises a base 24 crossed by the body of the nozzle 10, and a side wall 25 erected around the base 24. The side wall 25 comprises a bore 26 to receive the gas inlet 22. As shown in , the collar has two bores such as 26 to receive two gas inlets such as 22. The two gas inlets 22 are diametrically opposed and are oriented so that their respective flows are oriented along the same distribution axis W. The distribution axis W of the gas in the collar 20 intersects with the body of the nozzle 10, as shown in FIG. . Depending on the method of implementation of the , the two gas inlets 22 supply the collar 20 with gas upstream of the spray orifice 14, so that the dispensed gas is located around the nozzle body and surrounds the spray sprayed by the spray orifice 14. In this configuration, a setback distance dg of the gas inlets 22 relative to the opening 4 is greater than a distance between the spray orifice and the opening.

The nozzle body is cylindrical, the bottom 24 and the side wall 25 are arranged to define an annular volume around the nozzle body. The side wall comprises an internal annular restriction 27 such that the internal volume delimited in the collar comprises the annular volume 28 around the nozzle body and a cylindrical volume 29, in fluid continuity with the annular volume 28. The spray orifice 14 is designed to open centrally, such that the spray orifice 14 is at all points equidistant from the internal annular restriction 27. The spray axis Y of the spray orifice 14 is substantially parallel to the main elongation axis of the collar 20.

Inside the collar 20, there is therefore the distribution of a liquid spray through the distribution orifice 14 and of gas through the gas inlet(s) 22. The device therefore allows a joint distribution of liquid and gas. And as has been demonstrated at the experimental level, the presence of the collar contributes to a very significant improvement, as shown of the proportion of ozone dissolved in the liquid sprayed with a device according to the invention. Indeed, the presence of gaseous ozone in the first few centimeters at the outlet of the distribution orifice contributes to a very significant increase in the ozone dissolved in the liquid that is sprayed. The collar contributes to the formation of a chamber for confining the gaseous ozone around the liquid spray, and even better around the film of this spray.

The spray orifice is at a withdrawal distance “dr” from the opening 4. And as schematically represented, turbulence T is observed in the gaseous ozone due to an air suction phenomenon A at the level of the distribution opening 4. The withdrawal distance is of the order of a few centimeters, for example between 4 and 10 cm.

This containment chamber makes it possible to triple the proportion P3 of dissolved gas in the sprayed liquid compared to a reference value P1 which corresponds to the proportion of dissolved gas in the liquid before spraying. Another advantage of the device according to the invention is that it allows a strong enrichment in dissolved ozone, and a limitation of the phenomenon of desorption of the ozone dissolved in the sprayed liquid. Thanks to the invention, at a distance D of 1 meter from the opening, this proportion P3 of dissolved ozone is equal to that of the liquid in the tank. This result makes it possible to improve the efficiency of the phytosanitary treatments based on ozonated water thus distributed.

A device according to the invention, with a collar, demonstrates an efficiency 20 times greater than that of a simple device.

In particular, this containment chamber comprises the annular volume 28 and the truncated volume 29 minus the space taken up by the sprayed liquid. At a minimum, the containment chamber extends between the spray orifice 14 and the opening 4. Indeed, in alternative embodiments of a device according to the invention, the configuration of the collar may be devoid of the truncated volume 28, because the gas inlets 22 are arranged in the side wall 25 at a location situated between the opening 4 and the spray orifice 14.

The spray orifice distributes the liquid in a spray having an envelope surface. In a case where the collar defines a truncated cone-shaped volume 29 of circular section, and where the envelope surface of the spray is also truncated cone-shaped of circular section, then the width of the spray and the width of the opening can be respectively measured along any axis. However, when the nozzle 10 comprises a spray orifice 14 in the form of a longitudinal slot along an axis Z, such that the spray is in the form of a jet of a film along the axis Y perpendicular to this axis Z, then the width of the spray of this envelope surface and the width of the opening are measured along this axis Z. In particular, the configuration of the nozzle 10 and of the collar 20 is such that the width of the spray “ls”, measured at a distance “dr” from the spray orifice without a collar, is between 80% and 140% of the width “lo” of the opening 4 along this axis Z.

When the film extends at the nozzle outlet in a plane containing the Z axis, and forms there a continuous surface 15 bordered by filaments 16 and ending in drops 17, the width “lf” of the continuous surface 15, , measured along the Z axis at a distance equal to the withdrawal distance dr of the spray orifice without collar is between 40% and 120% of the width of the opening 4 along this Z axis. The cumulative distance D1 and D2 can in particular represent between 40% and 120% of the withdrawal distance “dr”.

As can be seen on the , the Z axis of the slot formed by the spray orifice is not necessarily parallel to the gas distribution axis W.

Perpendicular to the width measurements, when the nozzle 10 has a spray orifice 14 in the form of a longitudinal slot, a maximum thickness “Es” of the spray can be defined along an axis perpendicular to the Z axis. In this case, the opening 4 is preferably configured to have a slot shape, , of width “lo” and thickness “Eo”, such that the maximum thickness “Es” of the spray, measured at a distance “dr” from the spray orifice without a collar, is between 80% and 140% of the thickness “Eo” of the opening 4 perpendicular to this axis Z.

The spray width and thickness measurements are carried out in the absence of the collar, because turbulence is more particularly observed in a portion corresponding to the length D2 of the spray, that in which the continuous surface of the sprayed liquid undulates, such that this turbulence locally modifies the dimensions of the spray observed in the collar, and can be modulated by the gas flow rate at the gas inlets 22 determined in the confinement chamber.

When the width exceeds 100% of the opening width respectively, then a phenomenon of runoff of a part of the sprayed liquid is observed along the side wall. A preferential proportion of the ratio between the width of the distribution opening lo and the width of the spray ls is 95% to 120%.

In the variant of Figures 7 to 9, where the opening defines a slot and where the spraying is done via a spray orifice provided with a slot, the gas inlets 22 are diametrically opposed along the axis of the slot, and are located set back from the opening 4, by a distance dg less than the setback distance dr of the spray orifice relative to the opening 4.

Optionally, the tank 7 can also be supplied by a pipe 18 with gas provided by an ozone generator 13 so that the distributed liquid is already enriched with dissolved ozone before even being sprayed and is additionally charged with dissolved ozone in the containment chamber.

Claims (11)

Spraying device (1), in particular for spraying ozonated water in an agricultural environment, the device comprising
a joint distribution opening (4) for liquid and gas,
a nozzle (10) intended to be connected to a reservoir (7) of liquid to be sprayed,
a gas inlet (22) of a gas production and/or storage device (9, 13),
and a collar (20) surrounding the nozzle and the gas inlet, such that an edge (21) of this collar defines the dispensing opening of the device, and that a spray orifice (14) of the nozzle is at a setback distance (dr) in the collar relative to this dispensing opening,
characterized in that the collar defines a containment chamber (28, 29) for the gas emitted by the gas inlet, the containment chamber extending between the spray orifice and the dispensing opening. Spraying device according to claim 1 characterized in that the nozzle has a speed of spraying the liquid through the spray orifice, the gas production and/or storage device has a speed of distribution of the gas through the gas inlet, such that the speed of spraying the liquid is between 100 and 300 times the speed of distribution of the gas. Spraying device according to claim 1 or 2, characterized in that the spray orifice distributes the liquid according to a spray distributed spatially in at least one plane such that a width (lo) of the opening measured in this plane and orthogonally to a spray axis (Y) of the nozzle represents between 80% and 140%, and more particularly between 95% and 120% of a spray width (ls) in this same plane for a spray produced by said nozzle without its collar, this spray width being measured at a distance from the spray orifice equal to the withdrawal distance (dr). Spraying device according to any one of the preceding claims, characterized in that the spray orifice distributes the liquid according to a spray distributed spatially in at least one plane and having a spray thickness (Es) transverse to this plane such that a thickness of the opening (Eo) measured transversely to this plane represents more than 100%, in particular less than 140% of the spray thickness transversely to this same plane for a spray produced by said nozzle without its collar, the spray thickness being measured at a distance from the spray orifice equal to the withdrawal distance (dr). Spraying device according to any one of the preceding claims, characterized in that the spray orifice distributes the liquid in a spray comprising a portion in the form of a liquid film (11), and in that a length of this film measured along a spray axis (Y) of the nozzle (10) represents between 40 and 120% of the withdrawal distance (dr). Spraying device according to any one of the preceding claims, characterized in that the spray orifice (14) forms a longitudinal slot along an elongation axis (Z), and the distribution opening (4) has a main elongation axis parallel to the axis of the slot. Spraying device according to any one of the preceding claims, characterized in that the gas inlet is set back in the collar relative to the distribution opening (4), this setback of the gas inlet (dg) being able to be greater than the setback distance (dr). Spraying device according to any one of the preceding claims, characterized in that it comprises at least two equally distributed gas inlets connected to the same gas production and/or storage device (9). Spraying device according to any one of the preceding claims, characterized in that the spray orifice distributes the liquid according to a spatially distributed spray, such that the nozzle without its collar distributes a spray having a spray volume measured in a volume defined between the spray orifice and a withdrawal distance (dr) from this spray orifice, such that the spray volume occupies a volume less than 5% of an internal volume of the collar. Spraying device according to any one of the preceding claims, characterized in that the dispensing opening is unique, and the collar is formed by a continuous wall. Assembly for phytosanitary treatment comprising a spraying device according to any one of claims 1 to 10, characterized in that the gas production and/or storage device comprises a bypass towards the reservoir to enrich the liquid contained in the reservoir with gas, so that the liquid comprises a proportion of dissolved gas before spraying.