EP0057324B1 - Procédé et appareil pour la pulvérisation d'émulsions - Google Patents

Procédé et appareil pour la pulvérisation d'émulsions Download PDF

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Publication number
EP0057324B1
EP0057324B1 EP81306005A EP81306005A EP0057324B1 EP 0057324 B1 EP0057324 B1 EP 0057324B1 EP 81306005 A EP81306005 A EP 81306005A EP 81306005 A EP81306005 A EP 81306005A EP 0057324 B1 EP0057324 B1 EP 0057324B1
Authority
EP
European Patent Office
Prior art keywords
liquid
emulsion
orifice
charged
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP81306005A
Other languages
German (de)
English (en)
Other versions
EP0057324A1 (fr
Inventor
Ronald Alan Coffee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Imperial Chemical Industries Ltd
Original Assignee
Imperial Chemical Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Imperial Chemical Industries Ltd filed Critical Imperial Chemical Industries Ltd
Priority to AT81306005T priority Critical patent/ATE19597T1/de
Publication of EP0057324A1 publication Critical patent/EP0057324A1/fr
Application granted granted Critical
Publication of EP0057324B1 publication Critical patent/EP0057324B1/fr
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
    • B05B5/16—Arrangements for supplying liquids or other fluent material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/40—Mixing liquids with liquids; Emulsifying
    • B01F23/41—Emulsifying
    • B01F23/411—Emulsifying using electrical or magnetic fields, heat or vibrations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
    • B01F33/05—Mixers using radiation, e.g. magnetic fields or microwaves to mix the material

Definitions

  • This invention relates to spraying emulsions. More particularly, it relates to new processes for forming emulsions and spraying the emulsions so formed, and to apparatus therefor.
  • An emulsion consists of small particles (generally of mean diameter in the range 0.1 to 10 micrometres) of a first liquid dispersed in a second liquid immiscible therewith.
  • an emulsion may be formed of finely divided particles of oil in water; or conversely, of finely divided particles of water in oil, the latter being commonly referred to as an invert emulsion.
  • An emulsion is a two-phase system; the particles constitute the disperse phase, while the medium in which they are suspended is the continuous phase. The properties of emulsions naturally depend on the properties of the two phases, their relative proportions and the particle size of the disperse phase.
  • Dilute emulsions containing for example up to 10% or so of disperse phase, generally have, for example, a viscosity not dissimilar from that of the continuous phase; but increasing the proportion of the disperse phase leads to thickening, and the formation of immobile, scarcely pourable systems.
  • the present invention is concerned with relatively dilute emulsions, not too thick to be able to flow like liquids.
  • Emulsions have a variety of uses: for example in the food and pharmaceutical industries. Cosmetics may be formulated as emulsions, and so also may pesticides. The present invention relates to emulsions to be used as sprays.
  • Emulsions are generally formed by thoroughly agitating the two phases together, for example in a high shear mixer. This is a relatively inefficient process, consuming unnecessary energy. Moreover, emulsions so formed are not necessarily stable and may break down into separate bulk phases on storage. The present invention provides a more efficient method of forming emulsions, not dependent on mechanical mixing, and which prevents emulsion break-down by reducing or eliminating storage time.
  • dilute emulsions produced by such a technique may be electrostatically sprayed.
  • An electrostatic spraying process wherein the liquid to be sprayed is supplied to a surface adjacent a field intensifying electrode with a sufficient electrical potential difference applied between the electrode and the surface to atomise the liquid electrostatically is described in GB-A-1569707.
  • a process for forming and spraying a dilute emulsion of a first liquid in a second liquid immiscible therewith which comprises passing small amounts of the first liquid into a body of the second liquid while electrically charging the first liquid relative to the second liquid to a potential sufficient to cause emulsification therein, and effecting electrostatic atomisation of the charged emulsion thereby formed.
  • Such atomisation may conveniently be effected by passing the charged emulsion into a region of high electrical field strength thereby causing it to atomise.
  • the invention further comprises apparatus for forming and spraying dilute emulsion of a first liquid in a second liquid immiscible therewith which comprises an orifice formed in an electrically conducting material communicating with a vessel for containing the second liquid, means for delivering the first liquid to and through the orifice, means for charging the orifice to a high potential, and an electrostatic sprayhead for receiving the electrically charged emulsion formed at the orifice and for emitting the emulsion in the form of an electrically charged spray.
  • the sprayhead comprises an electrically conducting surface for receiving the electrically charged emulsion, and means for creating a field strength at the surface sufficient to atomise the emulsion therefrom in the form of a fine spray.
  • the emulsions being electrostatically charged, are attracted to spray targets and coat them more evenly than uncharged sprays would do. Electrostatic force fields carry the charged particles behind the target, so as to coat all sides of it.
  • the method and apparatus of the invention may be used for spraying paints and like coatings on to structures or articles of manufacture, and (with particular advantage) for spraying pesticides (e.g., insecticides, herbicides, fungicides and the like) on to crops or weeds.
  • pesticides e.g., insecticides, herbicides, fungicides and the like
  • Conveniently emulsions according to the invention comprise from about 1 to about 10% by weight disperse phase, through higher and lower amounts may be used where appropriate.
  • a container 1 of insulating material (glass) is provided with an earthed jacket 13 of conductive material, and with a conduit 2 for delivering liquid.
  • a metallic exit nozzle or electrostatic sprayhead 3 In the base of the container or vessel 1 is a metallic exit nozzle or electrostatic sprayhead 3, with a bore of capillary size.
  • an electrode in form of a metal ring 4 connected (as shown in Figure 2) to earth 19.
  • a second metallic exit nozzle or orifice 7, of capillary dimensions is provided in the base of container 5 a second metallic exit nozzle or orifice 7, of capillary dimensions.
  • Both nozzles 3 and 7 are connected (as shown in Figure 2) to a source of high potential 8 (0-20 kilovolts, 200 microamp module) via a switch 9.
  • a source of high potential 8 (0-20 kilovolts, 200 microamp module)
  • a switch 9 Below the container 5, within the container 1, and symmetrically disposed around the outlet of the nozzle or orifice 7, is a second earthed electrode in form of a metal ring 10.
  • the nozzle or electrostatic sprayhead 3 may be closed by an exterior cap or bung 12.
  • a hydrocarbon oil 11 is passed into the container 1 from the conduit 2 until the level' of oil 11 is above the base of container 5.
  • An aqueous solution containing 7% by weight of Paraquat O dichloride is passed through conduit 6 into container 5.
  • Capillary-sized droplets of the aqueous solution pass out through nozzle or orifice 7 and sink through the oil 11.
  • the switch 9 is then closed, applying a voltage of the order of 15 kilovolts to the nozzles 7 and 3.
  • the oil in the container 1 becomes turbulent, exhibiting negative surface tension due to the electrical charge it carries.
  • the cap 12 is then removed, and the emulsion (containing about 4% weight disperse phase) issues from the nozzle or electrostatic sprayhead 3.
  • the electrical field between the nozzle or electrostatic sprayhead 3 and the earthed ring 4 causes the emulsion to atomise as fine particles, which pass outwards and are attracted to suitable targets, e.g. weeds.
  • suitable targets e.g. weeds.
  • the flows of oil 11 through conduit 2 and of aqueous solution through conduit 6 are adjusted to maintain the levels of liquid in containers 1 and 5 constant.
  • the particle size of the disperse phase in the emulsion may be controlled by control of the field strength at the nozzle or orifice 7; e.g., by varying the distance between the nozzle or orifice 7 and the ring 10, or, more conveniently, by varying the applied voltage. The stronger the field the smaller are the droplets.
  • the particle size of droplets in the atomised emulsion may be controlled by control of the field strength at the nozzle or electrostatic sprayhead 3. This may be done by varying the voltage on the nozzle or electrostatic nozzle 3, the position of the ring 4, or by applying a variable voltage (positive or negative with respect to the potential of the nozzle or electrostatic sprayhead 3) to the ring 4 instead of earthing it.
  • the same apparatus may be used, if desired, to form an emulsion in which water or an aqueous solution is the continuous phase and oil is the disperse phase, by feeding water to container 1 and oil to container 2.
  • the nozzle or orifice 7 may be charged by induction, as shown in Figure 3. If the nozzle or orifice 7 is connected to the earth 19, and the source of potential 8 to ring 10, a strong charge of opposite sign will be induced on nozzle or orifice 7 and liquid passing through will be charged by contact in the same way as if the nozzle or orifice 7 were connected to source of potential 8, except that the charge will be of opposite sign. An emulsion will be formed in just the same way, with the charging current being taken from earth. This saves current at nozzle or orifice 7, but slightly more is used at nozzle or electrostatic sprayhead 3, because the emulsion has to be discharged and recharged in the opposite sense before atomisation.
  • the power consumption of the device is not high, and is readily adapted to use in portable devices powered by dry cells, or even solar cells.
  • a vehicle e.g. a tractor or aircraft
  • a power source carried on the vehicle e.g. the tractor battery
  • Electrostatic atomisation of the emulsion has advantages over other atomisation techniques involving mechanical atomisation e.g. from a pressure nozzle or spinning cup or disc. Such advantages include lower energy usage, apparatus with fewer or no moving parts, and spray droplets of very regular and controllable size.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Electrostatic Spraying Apparatus (AREA)
  • General Preparation And Processing Of Foods (AREA)
  • Bakery Products And Manufacturing Methods Therefor (AREA)
  • Catching Or Destruction (AREA)

Claims (11)

1. Procédé pour la formation et la pulvérisation d'une émulsion diluée d'un premier liquide dans un deuxième liquide non miscible avec lui, qui comprend le passage de petites quantités du premier liquide dans une masse du deuxième liquide tout en chargeant électriquement le premier liquide par rapport au deuxième liquide à un potentiel suffisant pour provoquer une émul- sification dans ce dernier, et à effectuer la pulvérisation électrostatique de l'émulsion chargée ainsi obtenue.
2. Procédé suivant la revendication 1, dans lequel la pulvérisation est effectuée par passage de l'émulsion chargée dans une région de forte intensité de champ électrique.
3. Procédé suivant la revendication 1 ou 2, dans lequel le premier liquide est un pesticide.
4. Procédé suivant la revendication 1 ou 2, dans lequel le premier liquide est aqueux et le deuxième liquide est une huile.
5. Appareil pour la mise en oeuvre du procède de la revendication 1, qui comprend un orifice (7) prévu dans une matière électriquement conductrice, en communication avec une cuve (1) contenant le deuxième liquide (11), des moyens (6, 5) pour amener le premier liquide à et à travers l'orifice (7), et des moyens (8, 9) pour charger l'orifice (7) à un potentiel élevé, caractérisé en ce qu'il comprend une tête de pulvérisation électrostatique (3) pour recevoir l'émulsion électriquement chargée formée à l'orifice (7) et pour émettre l'émulsion sous la forme d'un jet pulvérisé électriquement chargé.
6. Appareil suivant la revendication 5, dans lequel la tête de pulvérisation comprend une surface (3) électriquement conductrice, avec des moyens (4) pour créer une intensité de champ, à la surface, suffisante pour pulvériser l'émulsion sous la forme d'un jet finement pulvérisé.
7. Appareil suivant la revendication 6, dans lequel les moyens pour créer l'intensité de champ à la surface comprennent un électrode (4) à un potential différent de celui de la surface.
8. Appareil suivant la revendication 7, dans lequel l'électrode (4) est reliée à la terre.
9. Appareil suivant l'une quelconque des revendications 5 à 7, qui comporte une électrode (10) près de l'orifice (7), à un potentiel différent de celui de l'orifice, pour intensifier le champ électrique à cet endroit.
10. Appareil suivant la revendication 9, dans lequel l'électrode (10) adjacente à l'orifice (7) est reliée à la terre.
11. Appareil suivant l'une quelconque dés revendications 5 à 10, monté sur un véhicule et prévu pour la pulvérisation en agriculture.
EP81306005A 1981-01-30 1981-12-21 Procédé et appareil pour la pulvérisation d'émulsions Expired EP0057324B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81306005T ATE19597T1 (de) 1981-01-30 1981-12-21 Verfahren und vorrichtung zum verspruehen von emulsionen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8102823 1981-01-30
GB8102823 1981-01-31

Publications (2)

Publication Number Publication Date
EP0057324A1 EP0057324A1 (fr) 1982-08-11
EP0057324B1 true EP0057324B1 (fr) 1986-05-07

Family

ID=10519331

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81306005A Expired EP0057324B1 (fr) 1981-01-30 1981-12-21 Procédé et appareil pour la pulvérisation d'émulsions

Country Status (7)

Country Link
EP (1) EP0057324B1 (fr)
JP (1) JPS57159564A (fr)
AT (1) ATE19597T1 (fr)
AU (1) AU7917082A (fr)
CA (1) CA1176508A (fr)
DE (1) DE3174591D1 (fr)
NZ (1) NZ199410A (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8819378D0 (en) * 1988-08-15 1988-09-14 Atomic Energy Authority Uk Enhanced solvent extraction
US7712687B2 (en) 1999-08-18 2010-05-11 The Procter & Gamble Company Electrostatic spray device
US6682004B2 (en) 1999-08-18 2004-01-27 The Procter & Gamble Company Electrostatic spray device
US7152817B2 (en) * 1999-08-18 2006-12-26 The Procter & Gamble Company Electrostatic spray device
US6814318B2 (en) 1999-08-18 2004-11-09 The Procter & Gamble Company Disposable cartridge for electrostatic spray device
AU2002234776A1 (en) 2002-03-01 2003-09-16 Unilever Plc Electrostatic spraying of a cosmetic composition
WO2007131917A1 (fr) * 2006-05-15 2007-11-22 Unilever Plc Procédé de préparation d'une émulsion
JP4877173B2 (ja) * 2007-09-21 2012-02-15 パナソニック電工株式会社 静電霧化装置およびそれを備えた加熱送風装置
CN110935338A (zh) * 2019-09-24 2020-03-31 福建爱溥环保设备有限公司 油水混合成絮状物的装置及方法

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR639245A (fr) * 1927-08-09 1928-06-16 Procédé pour préparer des émulsions au moyen d'une charge élec trique
GB320919A (en) * 1928-06-19 1929-10-21 Provia Soc Improved process of and apparatus for making bituminous emulsions and distributing same on road surfaces
FR1017481A (fr) * 1950-02-07 1952-12-11 Onera (Off Nat Aerospatiale) Perfectionnements apportés aux moyens pour la production de particules électrisées, notamment de gouttelettes électrisées
BE519260A (fr) * 1952-04-18
FR1122243A (fr) * 1955-01-07 1956-09-04 Bonnet Reymond Sa Atomiseur perfectionné
FR1182266A (fr) * 1957-04-15 1959-06-24 Vanne automatique avec trompe d'émulsion
US3131131A (en) * 1962-04-03 1964-04-28 Socony Mobil Oil Co Inc Electrostatic mixing in microbial conversions
FR2199666A6 (fr) * 1972-09-18 1974-04-12 Ransburg Corp
GB1569707A (en) * 1976-07-15 1980-06-18 Ici Ltd Atomisation of liquids
GB1564973A (en) * 1976-12-30 1980-04-16 Research Corp Electrostatic spray nozzle system

Also Published As

Publication number Publication date
ATE19597T1 (de) 1986-05-15
CA1176508A (fr) 1984-10-23
NZ199410A (en) 1985-08-16
EP0057324A1 (fr) 1982-08-11
AU7917082A (en) 1982-08-12
DE3174591D1 (en) 1986-06-12
JPS57159564A (en) 1982-10-01

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