Electrostatic Spray Device

Abstract

An electrostatic spray atomisation device is disclosed. The device comprises a spray electrode disposed in a first recess in a dielectric surface, the spray electrode being connected, in use, in an electric circuit with a reference electrode enabling a potential difference to be applied between the spray and reference electrodes to atomise a liquid. Various techniques for dealing with problems of liquid deposition around the electrodes are described. The techniques may be used alone or in combination.

1 . An electrostatic spray atomisation device comprising: a spray electrode disposed in a first recess in a surface, the spray electrode being operatively connected through an electric circuit to a reference electrode, where the region of the surface adjacent to the first recess has a shape to draw liquid deposited on the region towards the spray electrode.  
   
   
       2 . The apparatus of  claim 1  where the surface is a dialectric.  
   
   
       3 . The apparatus of  claim 1  where the surface is characterized by being one or a combination of: oleophillic, oleophobic, lyophilic or lyophobic.  
   
   
       4 . The apparatus of  claim 1  where the shape is comprised of one or more channels in the surface.  
   
   
       5 . The apparatus of  claim 1  where the shape is comprised of a rough texture whose Roughness Average is between approximately 1 micron to approximately 1 millimeter.  
   
   
       6 . The apparatus of  claim 4  where at least one of said channels is in liquid communication with a reservoir.  
   
   
       7 . The apparatus of  claim 2 , wherein the reference electrode is disposed in a second recess in the surface, said second recess having a side wall.  
   
   
       8 . The apparatus of  claim 7 , wherein the second recess is comprised of at least one channel formed in the side wall of the recess.  
   
   
       9 . The apparatus of  claim 4 , wherein the at least one of said channels provides a dispersion path for the liquid over the surface.  
   
   
       10 . The apparatus of  claim 4 , wherein the at least one channel has either or both a substantially v-shaped cross-section or a cross section with a radius of curvature less than approximately 0.5 millimeters.  
   
   
       11 . The apparatus of  claim 4 , wherein the at least one channel has either or both a substantially rounded or a semi-circular shaped cross-section.  
   
   
       12 . The apparatus of  claim 6 , wherein liquid deposited on the surface is drawn to the reservoir at least partially by virtue of gravity.  
   
   
       13 . The apparatus of  claim 6 , wherein liquid deposited on the surface is drawn to the reservoir at least partially by virtue of capillary attraction.  
   
   
       14 . The apparatus of  claim 14 , wherein the surface is adapted to draw any of the liquid deposited on the surface in the region of the first recess towards the spray electrode by chemical affinity between the liquid and the surface.  
   
   
       15 . The apparatus of  claim 14 , wherein the chemical affinity is provided by either a oleophilic or oleophobic coating.  
   
   
       16 . The apparatus of  claim 1 , wherein the chemical affinity is provided by either a lyophilic or lyophobic coating.  
   
   
       17 . The apparatus of  claim 6 , further comprising a porous member within the reservoir to absorb liquid.  
   
   
       18 . The apparatus of  claim 17 , wherein the porous member is a sponge.  
   
   
       19 . An electrostatic spray atomisation device comprising: a spray electrode that emits a liquid disposed in a first recess in a dielectric surface, the spray electrode being operatively connected through an electric circuit to a reference electrode, whereby an electric field is generated between the spray electrode and the reference electrode when the electric circuit is provided power, and further comprising a means to distort the electric field when the liquid is deposited on the surface adjacent to the first recess.  
   
   
       20 . In an electrostatic spray atomization device comprised of a spray electrode that sprays a liquid and an adjacent surface, a method of controlling dispersal of the liquid on the adjacent surface comprised of: causing the liquid deposited on the adjacent surface to make electrical contact with the spray electrode.