EP0134951A1 - Process and device for the large area dispensing and spreading of electrically conducting liquids - Google Patents

Abstract

1. Process for the large-area application and distribution of electrically conductive liquids having a specific resistance of < 10**4 OMEGA . m, in which a high voltage is applied to the liquid, characterised in that the liquid is allowed to issue from a nozzle or capillary at such a low rate of flow that, immediately downstream of the nozzle or capillary, it forms a cohesive filament of liquid which then disintegrates into individual drops and in that, by means of the high voltage relative to earth which is applied to the filament of liquid, the drop size is stabilised and a conical distribution of drops (cone of drops) is produced whose apex angle depends on the level of the voltage.

Description

The invention relates to a method and a device for dispensing and distributing electrically conductive liquids with a specific resistance <10 ⁴ Ω.m, in particular aqueous plant protection agent solutions.

The spraying of liquids, in particular solutions or dispersions, under the action of electrical fields is known from various fields of technology. Examples include coating with paints in the automotive industry and the widespread use of crop protection agents in agriculture. Plant protection products are sprayed in a known manner as dispersions in water in the form of suspensions or emulsions using nozzles or rotary atomizers over the plant stands to be treated and are more or less successfully deposited on the leaves of the plants, mainly on the top of the free-standing leaves.

In order for the crop protection agents to be effective, however, it is necessary that the underside of the leaves and the stems are also hit by the sprayed preparation. When spraying outdoors, part of the spray is often driven off by the wind and carried to other plants that should not be treated. Furthermore, a large part is lost through sinking to the ground or through drifting. For this reason, a method has been specified in which the dissolved preparation is atomized electrostatically on a high-voltage electrode, the resulting, very fine aerosol droplets being highly charged unipolarly. With this method, the liquid can be deposited more effectively on earthed objects, since the plants attract the charged droplets as a counter electrode to the atomizing electrode. However, the method has the disadvantage that only organic liquids whose specific electrical resistance is in a certain range (approx. 10 ⁴ Ω.m to 10 ⁷ Ω.m) can be atomized and separated electrostatically. In particular, aqueous solutions cannot be processed because of the too high surface tension and the too low specific resistance (g ~ = 5.73i.m).

Another disadvantage is that the uploaded, very fine droplets, especially in dense plant populations, are only separated on the outer parts of the plants, but not in the electric ones penetrate shielded inner parts of the stocks. Furthermore, the charge level of the drops cannot be controlled in a simple manner, since only a high charge of the liquid at the edge of the spray electrode initiates the atomization effect. When the electrode voltage is reduced, only the atomization process changes into a dripping of the liquid.

• 1. Wäßrige, nicht brennbare Formulierungen sind organischen Flüssigkeiten vorzuziehen.
• 2. Die Tropfengrößen sollen im Bereich von 100 - 250 µm liegen.
• 3. Die Eindringtiefe der Flüssigkeitstropfen in den Pflanzenbestand soll einstellbar sein. Unter der "Eindringtiefe" wird dabei der Bereich verstanden, der beim Sprühvorgang von oben her gesehen; d.h. von der Spitze der Pflanze aus, erfaßt wird. Die Eindringtiefe könnte z.B. durch Veränderung der Tropfengröße oder durch Veränderung der Tropfenladung variiert werden. Schwere, ungeladene Tropfen fallen auf dem kürzesten Wege zu Boden. Dagegen werden leichte, hochgeladende Tröpfchen aus der Flugbahn des freien Falles am stärksten abgelenkt und von den am weitesten hervorstehenden Teilen der Pflanzen angezogen. Beide Extremfälle sind unerwünscht. Angestrebt wird vielmehr ein Verfahren, daß die gezielte Einstellung des Verhältnisses von Tropfenladung zu Tropfenmasse ermöglicht, da auf diese Weise die Zonen zwischen den obersten und den untersten Schichten der Bestände erfaßt werden können.

The following requirements result from practical experience in the application of pesticides:

• 1. Aqueous, non-flammable formulations are preferable to organic liquids.
• 2. The drop sizes should be in the range of 100 - 250 µm.
• 3. The depth of penetration of the liquid drops into the plant population should be adjustable. The “penetration depth” is understood to mean the area seen from above during the spraying process; ie from the top of the plant. The depth of penetration could be varied, for example, by changing the drop size or by changing the drop charge. Heavy, uncharged drops fall to the ground by the shortest route. In contrast, light, uploaded droplets are most distracted from the trajectory of free fall and are attracted to the most protruding parts of the plants. Both are extreme cases undesirable. Rather, the aim is a method that enables the targeted setting of the ratio of drop charge to drop mass, since in this way the zones between the top and bottom layers of the stocks can be detected.

The invention has for its object to develop a method for the large-area distribution of aqueous liquids and the necessary device, wherein the above conditions are met.

This object is achieved in that the liquid is discharged from a nozzle or capillary at such a low flow rate that it forms a coherent liquid thread immediately behind the nozzle or capillary, which then disintegrates into individual drops and that by applying an electrical one Voltage on the liquid thread, at least 500 V to earth, the drop size is stabilized and a spray or rain cone is generated, the opening angle of which depends on the level of the voltage.

The flow rate is preferably adjusted, taking into account the dimensions of the nozzle or the capillary, via the operating pressure so that the length of the continuous liquid thread behind the outlet opening is 2 to 100 mm, preferably 5-20 mm. This is practically achieved for a capillary a few millimeters long at a liquid pressure of 0.1 to 10 bar, preferably 1 to 3 bar.

It has been found that the depth of penetration of the droplets in dense plant stands can be controlled by changing the liquid pressure.

The device for carrying out the spraying process is characterized by a multiplicity of fluidically connected nozzle elements which consist of capillaries, each of the capillaries being surrounded by a concentric protective jacket which is at the same electrical potential as the capillaries, and by a high-voltage generator, whose high-voltage side output is conductively connected to the liquid flowing through the capillaries. The protective jacket is closed on one side by a base plate and forms a pot, the bottom of which is pierced by the capillary. The liquid to be distributed is supplied from a storage container connected to the capillary. The spray point, i.e. the end of the capillary is inside the pot. The upstream pressure required to maintain the flow is generated by a pump that keeps the reservoir at positive pressure.

The entire device can be constructed to save space. In particular, a portable sprayer can be implemented that works on this principle. Accordingly, a further development of the invention is that a carrier is provided on which the nozzle elements are arranged and the carrier on a rod-shaped Mount is attached, which contains a battery-operated high-voltage generator, an air pump for generating the pressure on the capillaries and a storage container for the liquid to be distributed.

Special embodiments and developments of the invention are described in the subclaims.

• a) Es wurde gefunden, daß sich mit dem neuen Verfahren wäßrige Lösungen, ebenso wie Salzlösungen sowie wäßrige Suspensionen und Emulsionen problemlos versprühen und auf Zielobjekten niederschlagen. Derartige Flüssigkeiten können bekanntlich auf rein elektrostatischem Wege nicht zerstäubt werden.
• b) Die Tropfenaufladung oder das Ladung/Masseverhältnis der Tropfen ist durch die Höhe der angelegten Spannung bestimmt und kann in weiten Grenzen eingestellt werden. Damit ergibt sich die Möglichkeit, die Sprühcharakteristik über die elektrische Spannung zu steuern. Dieser Vorteil, der für die Anwendung von Pflanzenschutzformulierungen von großer Wichtigkeit ist, kann bei den bekannten rein elektrostatischen Verfahren für die Zerstäubung von Flüssigkeiten ebenfalls nicht erreicht werden.
• c) Ein weiterer Vorteil besteht darin, daß nur relativ niedrige Flüssigkeitsdrucke erforderlich sind. Der notwendige Vordruck kann mit Hilfe von Pumpen einfacher Bauart erzeugt werden.
• d) Das erfindungsgemäße Verfahren kann mit geringem apparativem Aufwand verwirklicht werden. Insbesondere kann die Vorrichtung so kompakt und raumsparend aufgebaut werden, daß nunmehr tragbare, leicht zu bedienende Sprühgeräte für wäßrige Pflanzentschutzformulierungen zur Verfügung stehen.
• e) Da bei dem Verfahren nur relativ große Tropfen mit einem engen Tropfengrößenspektrum entstehen, werden gesundheitsschädliche Aerosole bzw. Nebel (Personengefährdung durch Einatmen) vermieden.

The following advantages are achieved with the invention:

• a) It has been found that aqueous solutions, as well as salt solutions and aqueous suspensions and emulsions, spray easily with the new process and are deposited on target objects. As is known, such liquids cannot be atomized in a purely electrostatic way.
• b) The drop charge or the charge / mass ratio of the drops is determined by the level of the applied voltage and can be set within wide limits. This results in the possibility of controlling the spray characteristic via the electrical voltage. This advantage, which is of great importance for the use of crop protection formulations, cannot be achieved in the known purely electrostatic processes for atomizing liquids either.
• c) Another advantage is that only relatively low fluid pressures are required. The necessary form can be generated with the help of pumps of simple design.
• d) The method according to the invention can be implemented with little expenditure on equipment. In particular, the device can be so compact and space-saving that portable, easy-to-use sprayers are now available for aqueous crop protection formulations.
• e) Since only relatively large droplets with a narrow droplet size spectrum are produced in the process, harmful aerosols or mists (danger to persons through inhalation) are avoided.

• _Fig. 1 den Zerfall eines Flüssigkeitsfadens in Tropfen nach dem Austritt aus einer Kapillare;
• Fig. 2 die Erzeugung eines Regenkegels durch Anlegen einer elektrischen Spannung an den Flüssigkeitsfaden;
• Fig. 3a,b die Steuerung der Eindringtiefe des Regenkegels bei der Behandlung von Pflanzenbeständen;
• _Fig. 4a,b die Steuerung der Eindringtiefe des Regenkegels durch Änderung der Richtung;
• Fig. 5a,b eine Möglichkeit zur Erhöhung der Raumladungsdichte am Zielort durch mehrere gerichtete Regenkegel;
• Fig. 6 schematisch ein komplettes tragbares Verteilgerät;
• Fig. 7 den bei der Vorrichtung gemäß Fig. 6 verwendeten Träger mit Düsenelementen und
• Fig. 8 ein einzelnes Düsenelement.

Before the invention using exemplary embodiments and. Described in more detail in the drawings, the principle and the basic physical conditions of the new method are to be explained in more detail below. Show it

• _F ig. 1 the disintegration of a liquid thread into drops after exiting from a capillary;
• 2 shows the generation of a rain cone by applying an electrical voltage to the liquid thread;
• 3a, b control the depth of penetration of the rain cone in the treatment of plant stands;
• _F ig. 4a, b the control of the depth of penetration of the rain cone by changing the direction;
• 5a, b show a possibility for increasing the space charge density at the target location by means of several directed rain cones;
• Fig. 6 schematically shows a complete portable distribution device;
• Fig. 7 shows the carrier used in the device according to Fig. 6 with nozzle elements and
• Fig. 8 shows a single nozzle element.

As is known, a water jet emerging from a simple perforated nozzle or capillary at low speed disintegrates in a defined manner into drops of a certain size. The smooth jet part or liquid thread still connected at the exit point shows, after a short initial distance, periodically recurring constrictions, which deepen as the distance from the outlet opening increases, until individual drops are finally separated, the diameter of which is directly related to the diameter of the connected one Beam part stands. This process is shown in Fig. 1. From the capillary 1 with a diameter of 100 microns, a liquid jet 2 (eg water) with a speed V = 6 m / sec. ejected, the shape of which initially remains cylindrical over a distance of a few cm, but then shows constrictions 3 on the surface which are the same Repeat the distances and deepen them further until individual drops 4 finally detach from the jet.

The lower range limit for the speed of the outflowing liquid is reached when no more continuous liquid thread forms at the outlet opening, but instead the liquid drips off. The upper limit for the exit velocity of the liquid is given when the laminar flow changes into a turbulent one and the disintegration into drops of the same size is replaced by an atomization process, with a wide spread of the drop sizes occurring. The decay of a liquid thread into drops described here is referred to as "natural jet decay".

In der Praxis kann für die Wellenlänge λ = 4,5 _D gesetzt werden. Neben den Tropfen 4 mit dem rechnerisch zu ermittelnden Durchmesser d entstehen zusätzlich mit einem sehr kleinen Volumenanteil sekundäre Satellitentröpfchen 5, deren Durchmesser d_s z..B. bei d_s = 0,2 d liegt. Verfolgt man die so erzeugten Tropfen auf ihrer Flugbahn, z.B. über die Flugstrecke von 1 m, so stellt man fest, daß ein großer Teil der Tropfen durch Rekombination in größere Tropfen 6 und 7 umgewandelt wird. Anstelle der erwarteten Tropfengrößen d = 189 µm, ergeben sich Tropfen, deren Größe im Bereich von 190 bis 800 µm, d.h. weit außerhalb des gewünschten Bereiches liegt. Der Vorgang der Rekombination der Tropfen auf dem Flugwege kann photographisch nachgewiesen werden.The diameter d of the drops 4 in the case of natural beam decay can be calculated from the beam diameter D and the distance of the constrictions or the decay wavelength λ using the following formula:

In practice, λ = 4.5 _D can be set for the wavelength. In addition to the droplets 4 with the diameter d to be calculated, secondary satellite droplets 5 are also formed with a very small volume fraction, the diameter d _{s of which, for} example. at d _s = 0.2 d. If you follow the drops so generated on your Trajectory, for example over the flight distance of 1 m, it is found that a large part of the drops is converted into larger drops 6 and 7 by recombination. Instead of the expected drop sizes d = 189 µm, drops result whose size is in the range from 190 to 800 µm, ie far outside the desired range. The process of recombining the drops on the flight paths can be demonstrated photographically.

Surprisingly, it has been found that recombination into larger drops can be prevented if an electrical voltage to earth is applied to the connected part of the electrically conductive liquid thread. The drops remain in their original size and reach the catcher unchanged, even if it is far away. In addition, a wide-open cone (rain cone) is made up of electrically charged droplets, which can be deposited specifically on grounded objects. This process is shown in Fig. 2. The flow conditions are the same as in the jet decay according to FIG. 1, but with an electrical voltage of 10 kV with respect to earth, which is applied to the continuous liquid thread 2. The capillary 1 consists of an electrically conductive material, for example metal, and has a ratio of length to diameter of approximately 50: 1. The liquid pressure at the capillary is set to values from 0.1 to 10 bar, preferably in the range from 1 to 3 set in bar. Under these conditions it follows the capillary is a coherent liquid thread with a length of 2 to 100 mm, preferably 5 to 20 mm. Instead of capillaries, simple hole nozzles can also be used for the jet generation, the hole diameter of which is in the range from 50 μm to 500 μm, preferably between 100 μm and 200 μm. The ratio between length and width of the perforated nozzle is, for example, 3: 1.

The high voltage in the range from 10 to 50 kV, which is supplied by the high-voltage device 8, is applied to the coherent liquid thread 2 via the capillary 1. The voltage and the electrical field caused thereby influence a high-density electrical charge on the surface of the conductive liquid thread, the highest density of the surface charge occurring at the end of the liquid thread, for example at point 9. The detaching drops 4 and 5 take over part of this surface charge. An important role is played by the fact that it is a conductive liquid whose specific resistance is <10 ⁴ Ω.m. There is no limit to the resistance. The liquid can be of any conductivity.

In contrast to the flight path of the uncharged drops in the first section according to FIG. 1, which differs only slightly from the original beam direction, the electrically charged drops according to FIG. 2 show clearly diverging flight paths. The light satellite drops 5 leave the immediately after the formation Main trajectory and then move towards the next grounded body in the area. The normal drops formed from the bulk of the outflowing liquid later disengage and increase their mutual distance. This leads to the formation of the above-mentioned rain cone 10 with the opening angle cG. The drops remain in their original size even over flight paths of 1 m length and more. The effect of the electric field is based on two effects, namely the prevention of recombination into larger drops and the formation of a cone due to the electrostatic repulsion. Changing the polarity of the charge has no effect on these effects. The opening angle of the rain cone can be set to small or large depending on the height of the ejection speed at the capillary (liquid pressure), the jet thickness and the electrical voltage. This provides the opportunity for targeted droplet separation. By setting the direction, for example, a plant stand can either be sprayed flat, the charged droplets preferably reaching the upper parts of the plant, or it is sprayed on steeply; then the droplets are only separated in the lower parts of the stand. The depth of penetration of the droplets can thus be adapted to the particular requirements of the plant stands.

In Fig. 3a, b it is shown how by changing the liquid pressure in the nozzle and the verbun which jet exit speed can control the depth of penetration of the drops into dense plant populations. In partial image a, water is expelled from a nozzle 9 with a clear width d = 100 μm at a pressure of P ₁ = 0.6 bar with an average spraying speed V ₁ = 5.6 m / s. The beam is at a voltage of -15 kV, which is maintained by the high voltage device 10. Below the nozzle are two plants 11 and 12 of a larger plant population. The height of the plants is 0.5 m. The distance from the plant tip to the nozzle is 0.3 m. The rain cone 13 opens above the plants 11 and 12. With the low kinetic energy of the liquid thread, the drops are quickly braked by the air friction and quantitatively brought to separation by Coulomb forces in the upper parts of the plants 11 and 12. In partial image b, spraying at the same voltage, but with the pressure of 3 bar and the exit velocity V ₂ K of 16.8 m / s from the nozzle 14. The effective braking of the droplet movement takes place here only in the lower part of the plants 15 and 16, after which the electrostatic attractive forces predominate and the droplets in this area are separated. The cone 17 is less open than the cone 13. In both cases (a and b) the droplet size and the charge remain almost the same, so that the tendency towards targeted separation after braking the falling speed is retained.

According to FIG. 4a, the nozzle or the capillary 18 is arranged above the plant stock 19 so that they emerge de Liquid thread initially runs horizontally. The high voltage generator is omitted here. The rain cone generated is braked by the air resistance and then settles at a lower speed in the upper parts of the plants of the stand 19, so that only a small penetration depth is achieved. According to FIG. 4b, the beam direction is rotated through 90 ° relative to the first position; ie the capillary 21 is arranged vertically here. As in FIG. 4a, the high voltage source is not shown. The rain cone falls out of the capillary 21 into the plant stand 22 at a higher speed than in the arrangement according to FIG. 4a, since gravity acts in the same direction. This results in a greater depth of penetration. Precipitation then occurs preferably in the lower parts of the individual plants. It is obvious that one can vary the penetration depth as desired with other positions of the nozzles between these two extreme positions 18 and 21. So you have it in your hand to control the depth of penetration of the _R egenkegels in dense plant populations by changing the ejection direction of the liquid. If you move a series of such nozzles parallel to the ground over a field (drawn arrows), large-area plantings can be sprayed.

By simultaneously using a large number of nozzle elements, the space charge generated by the drops can be concentrated in the immediate vicinity of the target object. 5a, a space charge cloud 23 is formed by a plurality of nozzles 25 oriented in parallel high charge density in front of the target object 24. Fig. 5b shows another possibility to build a high Raumladun ^g sdichte means of a plurality of nozzles 26. The nozzles are oriented so here that the extension of the liquid filaments, ie, the initial directions of the beams at the location of the space charge 27 cross each other, whereby a strong Precipitation field on target object 28 arises. The nozzles are set up at a greater distance from each other and the jet directions are concentrated in one point of the room.

Fig. 6 shows a complete liquid distribution device, which is so compact and handy that it can be operated as a portable device by one person. It consists of a head 29, the liquid filter 30, the liquid valve 31, the reservoir 32 for the liquid to be distributed, a high-voltage generator 33, a battery housing 34 and an air pump 35. All parts are received by a rod-shaped holder 36 made of insulating material. The grounding of the electrical system is provided by a grounding cable 37, the free end of which lies on the ground or is in electrical connection with the object to be treated.

In order to put the device into operation, the air pump 35 pumps air into the container 32, which is partially filled with the liquid. Part of the volume remains free, for example, 30% for the compressed air (air cushion). The pressure in this volume is increased to 2 to 3 bar. The valve 38 prevents the liquid from flowing back. The distributor head 29 is placed under high voltage of, for example, 50 kV by switching on the high-voltage generator 33 via the switch 39, which closes the primary circuit. When the valve 31 is opened, the liquid flows out through the distributor head 29 and is applied over a large area in the manner indicated above.

The distributor head 29 is shown in FIG. 7. In principle, it consists of a plurality of fluidically connected nozzle elements which are connected to the liquid container 32 via the line 44. Short capillary tubes are very suitable for generating thin liquid jets, but they are very sensitive to contamination and damage when they come into direct contact with other objects, e.g. Plants, are. For this reason, the capillary is protected by a concentric jacket. Although the formation of an electric field is suppressed by the shielding effect of the jacket with the same potential of the protective jacket, there is no impairment of the spraying process. The contiguous first section of the liquid thread, which projects beyond the edge of the protective jacket, is because of the conductivity of the liquid a replacement for a tip electrode, on which the field is built up outside the cylinder, which is required for charging the drops.

7, the capillary 47 is inserted into the base plate of a pot 48 and thus forms a nozzle element 40 which is pressed into corresponding bores in the distributor head 29. The immersion depth is limited by the protruding edge 42 (collar of the pot 48). The free end of the capillaries 47 dips into the liquid channel 43, which in turn is connected to the feed pipe 44.

Since the capillaries 47 can easily become soiled due to deposits (incrustations) over a long period of use, a device for the simple, quick change of the nozzle elements 40 is required. For this purpose, each nozzle element 40 is wrapped in a ring 45 made of elastic material, the circumference of which is larger than the circumference of the carrier 41 for the nozzle elements. The ring 46 is drilled on its upper side (FIG. 7) and screwed to the carrier 41 on the opposite side (46). Through the bore in the elastic ring, the nozzle element 40 is now inserted into the carrier 41 in such a way that the collar 42 of the protective jacket 48 projects beyond the bore and thus forms a stop (see FIG. 8). To replace a nozzle element 40, press the ring 45 together (arrows Fig. 8). As a result, the ring 45 is deformed and exerts a force on the nozzle element 40 that is large enough to pull it out of the anchoring in the carrier 41. A new nozzle element can then be inserted through the bore in the ring 45 and inserted into the corresponding opening in the carrier 41. The exchange can be done by hand without the use of tools.

The diameter of the elastic ring 45 is 5 to 50 mm, preferably 10 to 30 mm. The length of the carrier 41 and the packing density of the nozzle elements 40 can be adapted to the needs. The latter is only limited by the mutual contact of the components.

There is a maximum for the amount of electrical charge in the droplets, which is reached when the electric field strength in the vicinity of the beam approaches assumes a value which, when exceeded, results in a corona discharge. The level of the optimal operating voltage depends on the dimensions of the equipment. It must therefore be determined experimentally. For a single nozzle element with a 100 µm capillary width and a distant counter electrode (at least 0.5 m), the optimal operating voltage is approx. 10 kV. The upper limit for the operating voltage is approx. 50 kV.

A great advantage of the device described, compared to known devices for generating electrically charged spray mist, is that no counter electrode with earth potential is required in the immediate vicinity of the high-voltage nozzle unit. This fact enables the use of very long insulating distances between the live parts of the arrangement. Malfunctions caused by damp air or pollution of the isolators can thus largely be ruled out. It is also important that only very small currents flow (order of magnitude pA), so that the battery used for power supply has a long service life and the high voltage generator can have a high internal resistance. In this way, danger to people from high voltage is avoided.

Claims (9)

1. Process for large-scale application and distribution of electrically conductive liquids with a specific resistance <10 ⁴ Ωm, in particular of aqueous crop protection agent solutions or dispersions, characterized in that the liquid is let out of a nozzle or capillary with such a low flow rate that it immediately behind the nozzle or capillary forms a coherent liquid thread, which then disintegrates into individual drops and that by applying an electrical voltage to the liquid thread, at least 500 V to earth, the drop size is stabilized and a conical drop distribution (rain cone) is generated, the opening angle of which depends on the level of tension. 2. The method according to claim 1, characterized in that the flow rate is adjusted due to the dimensioning of the nozzle or capillary and the selected operating pressure so that the length of the continuous liquid thread behind the outlet opening is 2 to 100 mm, preferably 5 - 20 mm. 3. The method according to claim 1 to 2, characterized in that the liquid pressure in front of the nozzle or capillary to values of 0.1 to 10 bar, preferably 1 to 3 bar. 4. The method according to claim 3, characterized in that the depth of penetration of the rain cone in dense plant stands is controlled by changing the liquid pressure. 5. Apparatus for carrying out the method according to claim 1 to 4, characterized by a plurality of fluidically connected nozzle elements (40) which consist of capillaries (47), each capillary (47) being surrounded by a concentric protective jacket (48), which is at the same electrical potential as the capillaries (47) and by a high-voltage generator, the high-voltage side output of which is conductively connected to the liquid flowing through the capillaries (47). 6. The device according to claim 5, characterized in that the protective jacket is closed on one side by a base plate and forms a pot, the bottom of which is pierced by the capillary (47) which is connected on the one hand to a reservoir (32) for the liquid and on the other hand ends within the pot. 7. The device according to claim 5 to 6, characterized in that the clear width of the capillaries (47) is in the range of 50 to 500 microns. 8. Apparatus according to claim 5 to 7, characterized in that the nozzle elements (40) are interchangeably inserted in a carrier (41) and each nozzle element (40) is wrapped by a ring (45) made of elastic material, which on one side is fastened to the carrier (41) and has a bore on the opposite side, through which the protective jacket (48) provided with a collar (42) projecting beyond the bore is passed. 9. Apparatus according to claim 5 to 8, characterized in that the carrier (41) with the nozzle elements (40) is attached to a rod-shaped holder (36) which has a battery-operated high-voltage generator (33), an air pump (35) for generating the Contains form on the capillaries (47) and a reservoir (32) for the liquid to be distributed.

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