Systems and Methods for An Electrostatic Atomizer of Moderately Conductive Fluids

Abstract

An electrostatic atomizer electrostatically atomizes a fluid into a charged spray, wherein the charged spray includes a plurality of charged droplets. The electrostatic atomizer includes a chamber forming an inlet and an exit aperture, wherein the chamber is configured for fluid to flow into the chamber from the inlet and to flow out of the chamber from the aperture. An emitter electrode is in liquid contact with the fluid in the chamber and injects an electrical charge into the fluid in the chamber. An impedance circuit is coupled to the chamber and configured to obtain a voltage difference between the emitter electrode and the exit aperture, wherein the voltage difference is at least a minimum voltage threshold.

1 . An apparatus for electrostatically atomizing a fluid into a plurality of charged droplets, comprising:
 a chamber forming an inlet and an exit aperture, wherein the chamber is configured for the fluid to flow into the chamber from the inlet and to flow out of the chamber from the aperture;   an emitter electrode in liquid contact with the fluid in the chamber, wherein the emitter electrode injects an electrical charge into the fluid in the chamber; and   an impedance circuit coupled to the chamber and configured to obtain a voltage difference (V a −V b ) between an emitter voltage V a  of the emitter electrode and an aperture voltage V b  of the exit aperture, wherein the voltage difference is at least a minimum voltage threshold.   
     
     
         2 . The apparatus of  claim 1 , wherein the fluid has a conductivity greater than 1 microSieman/meter (μS/m). 
     
     
         3 . The apparatus of  claim 1 , wherein the minimum voltage threshold is determined in response to a predetermined droplet diameter of the plurality of charged droplets. 
     
     
         4 . The apparatus of  claim 3 , wherein the minimum voltage threshold is approximately 400 V for a predetermined droplet diameter of 10 μm. 
     
     
         5 . The apparatus of  claim 3 , wherein the minimum voltage threshold is approximately 3300 V for a predetermined droplet diameter of 100 μm. 
     
     
         6 . The apparatus of  claim 1 , wherein the impedance circuit comprises a variable impedance circuit. 
     
     
         7 . The apparatus of  claim 6 , further comprising a controller configured to adjust an impedance of the impedance circuit to increase or decrease the aperture voltage V b  to maintain the voltage difference (V a − V b ) at least at the minimum voltage threshold. 
     
     
         8 . The apparatus of  claim 1 , further comprising:
 a power supply configured to supply the emitter voltage V a  to the emitter electrode; and   a controller configured to adjust the power supply to increase or decrease the emitter voltage V a  to maintain the voltage difference (V a − V b ) at least at the minimum voltage threshold.   
     
     
         9 . The apparatus of  claim 1 , further comprising:
 a controller configured to monitor one or more of: the emitter voltage V a ; or the aperture voltage V b ; or the voltage difference (V a − V b ) between the emitter voltage V a  and the aperture voltage V b .   
     
     
         10 . The apparatus of  claim 9 , wherein the controller is configured to adjust the emitter voltage V a ; or the aperture voltage V b ; or a combination of the emitter voltage V a  and the aperture voltage V b . 
     
     
         11 . A method by an electrostatic atomizer for electrostatically atomizing a fluid, comprising:
 monitoring one or more of: an emitter voltage V a  of an emitter electrode in liquid contact with the fluid in a chamber of the electrostatic atomizer; or an aperture voltage V b  of the chamber; or an emitter to aperture voltage (V a −V b );   determining one or more of: the emitter to aperture voltage (V a −V b ); the emitter voltage V a ; or the aperture voltage V b  are not within respective predetermined thresholds; and   adjusting the emitter voltage V a  and/or the aperture voltage V b .   
     
     
         12 . The method of  claim 11 , wherein determining one or more of: the emitter to aperture voltage (V a − V b ); the emitter voltage V a ; or the aperture voltage V b  are not within the respective predetermined thresholds comprises:
 determining the emitter to aperture voltage (V a − V b ) falls below a minimum voltage threshold V T . 
 
     
     
         13 . The method of  claim 11 , wherein adjusting the emitter voltage V a  and/or the aperture voltage V b  comprises one or more of:
 adjusting a power supply to the emitter electrode to increase or decrease the emitter voltage V a ; or   adjusting a variable impedance circuit to increase or decrease the aperture voltage V b .   
     
     
         14 . The method of  claim 11 , further comprising:
 injecting the fluid into the chamber, wherein the chamber forms an aperture;   injecting an electrical charge through the fluid, using the emitter electrode, as the fluid flows through chamber, past the emitter electrode and exits the aperture.   
     
     
         15 . The method of  claim 11 , further comprising:
 electrostatically atomizing the fluid into a charged spray, wherein the charged spray includes a plurality of charged droplets; and   directing the charged spray at a surface for a predetermined duration to decontaminate the surface.   
     
     
         16 . The method of  claim 15 , wherein the fluid is water and wherein the predetermined duration is 60 seconds or less. 
     
     
         17 . The method of  claim 15 , wherein droplets in the plurality of charged droplets are characterized by a K factor, wherein the K factor is a ratio of the electrostatic energy of the surface charges (W e ) and the surface energy (W s ), and wherein the K factor is less than one (K<1). 
     
     
         18 . The method of  claim 11 , further comprising:
 electrostatically atomizing the fluid into a charged spray, wherein the charged spray includes a plurality of charged droplets;   directing the charged spray at an evaporative surface to separate water from salt particulates; and   collecting the separated water.   
     
     
         19 . The method of  claim 18 , further comprising:
 applying heat and/or pressure to the evaporative surface to evaporate the separated water.   
     
     
         20 . The method of  claim 11 , wherein the fluid is saline water and further comprising:
 electrostatically atomizing the saline water into a charged spray, wherein the charged spray includes a plurality of charged droplets;   directing the charged spray at a surface of a material, wherein the material traps and/or attracts salt particulates in the plurality of charged droplets; and   collecting water residue not trapped by the material.