Atomization of liquids

• US 4,381,533 A
• Filed: 11/18/1981
• Issued: 04/26/1983
• Est. Priority Date: 07/15/1976
• Status: Expired due to Term

• Current Assignee: Zeneca Incorporated (Astrazeneca PLC)
• Original Assignee: Imperial Chemical Industries PLC (IMPERIAL CHEMICAL INDUSTRIES)
• Inventors: Coffee, Ronald A.
• Primary Examiner(s): Moose, Jr., Harry E.
• Application Number:
  US06/322,687
• Time in Patent Office: 524 Days
• Field of Search: 361/226, 361/227, 361/228, 361/235, 118/626, 118/627, 118/628
• US Class Current: 361/228
• CPC Class Codes: B05B 5/04 characterised by having rotary outlet or deflecting elements , i.e. spraying being also effected by centrifugal forces
• CPC Class Codes: B05B 5/043 using induction-charging
• CPC Class Codes: B05B 5/0531 Power generators
• CPC Class Codes: B05B 5/0533 Electrodes specially adapted therefor; Arrangements of electrodes
• CPC Class Codes: B05B 5/0535 at least two electrodes having different potentials being held on the discharge apparatus, one of them being a charging electrode of the corona type located in the spray or close to it, and another being of the non-corona type located outside of the path for the material
• CPC Class Codes: B05B 5/1691 Apparatus to be carried on or by a person or with a container fixed to the discharge device
• CPC Class Codes: H01L 21/324 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/20 - H01L21/288 and H01L21/302 - H01L21/322 take precedence
• CPC Class Codes: Y10S 43/90 Liquid insecticide sprayer

Abstract

Spraying apparatus for spraying liquid pesticides on to crops growing in the ground includes a plurality of electrostatic spraying devices mounted on a boom which can be mounted on a powered vehicle such as a tractor or an aircraft. Each spraying device includes a spray-head having an at least electrically semi-conducting surface charged to a potential of the order of 1-20 kilovolts, a field intensifying electrode mounted adjacent the spray-head surface and being so sited relative to the spray-head surface that the electrostatic field thereat causes pesticide liquid delivered thereto to atomize without substantial corona discharge to form electrically charged particles.

Claims

1. A spraying apparatus for spraying a liquid onto a plant comprising at least two spraying devices mounted on a boom each such spraying device comprising:

a spray-head having an at least electrically semi-conducting surface;

means for electrically charging the spray-head surface to a potential of the order of 1-20 kilovolts;

means for delivering spray liquid to the surface;

a field intensifying electrode mounted adjacent to the spray-head surface; and

means for connecting the field intensifying electrode to earth;

the electrode being so sited relative to the spray-head surface that when the spray-head surface is charged, the electrostatic field thereat causes liquid thereon to atomise without substantial corona discharge to form electrically charged particles which are projected past the electrode and into contact with the plant.

2. A tractor attachment for atomising liquid pesticide to form charged atomised spray particles and to project them along trajectories determined primarily by electrostatic forces to contact plants growing in the earth, said attachment comprising:

a boom attachable to a tractor;

sprayheads mounted on said boom each having an at least semi-conducting external surface defining a spray orifice;

means for electrically charging each sprayhead surface to a potential of the order of 20 kilovolts;

means to flow liquid to and through each orifice under gentle hydrostatic pressure;

a field-intensifying electrode mounted adjacent to each orifice and aside from and asymmetrically with respect to each said trajectory; and

means for electrically connecting said field-intensifying electrode to the earth in which the electrode being so sited relative to the surface that when the surface is charged by the charging means the electrostatic field thereat is sufficient without substantial corona discharge to draw the liquid out into a regular pattern of ligaments, which ligaments break up into a cloud of charged atomised spray particles which follow said trajectories to the plants so that the cloud wraps around the leaves of the plants and coats both the upper and lower surfaces of the leaves.

3. In combination with a powered vehicle a boom mounted on the vehicle and at least two spraying devices mounted on the boom for spraying a liquid onto a plant, each such spraying device comprising:

a spray-head having an at least electrically semi-conducting surface;

means for electrically charging the spray-head surface to a potential of the order of 1-20 kilovolts;

means for delivering spray liquid to the surface;

a field intensifying electrode mounted adjacent to the spray-head surface; and

means for connecting the field intensifying electrode to earth;

the electrode being so sited relative to the spray-head surface that when the spray-head surface is charged, the electrostatic field thereat causes liquid thereon to atomise without substantial corona discharge to form electrically charged particles which are projected past the electrode and into contact with the plant.

4. In combination with a tractor an attachment for atomising liquid pesticide to form charged atomised spray particles and to project them along trajectories determined primarily by electrostatic forces to contact plants growing in the earth, said attachment comprising:

a boom attached to the tractor;

sprayheads mounted on said boom each having an at least semi-conducting external surface defining a spray orifice;

means for electrically charging each sprayhead surface to a potential of the order of 20 kilovolts;

means to flow liquid to and through each orifice under gentle hydrostatic pressure;

a field-intensifying electrode mounted adjacent to each orifice and aside from and asymmetrically with respect to each said trajectory; and

means for electrically connecting said field-intensifying electrode to the earth in which the electrode being so sited relative to the surface that when the surface is charged by the charging means the electrostatic field thereat is sufficient without substantial corona discharge to draw the liquid out into a regular pattern of ligaments, which ligaments break up into a cloud of charged atomised spray particles which follow said trajectories to the plants so that the cloud wraps around the leaves of the plants and coats both the upper and lower surfaces of the leaves.