Patents Examined by Mary E. McCarthy
  • Patent number: 4422577
    Abstract: An electrostatic spraying nozzle, particularly for agricultural use, provides for a high rate of liquid delivery, up to 6 or 7 mL/s, while maintaining uniform charging of the atomized spray by means of a low-current supply. Atomization is produced centrifugally from a conical rotor and the liquid is charged by contact with an electrically isolated conductive coating on the surface of the rotor. The coating is raised to the potential of a high-voltage needle electrode by conduction through one or more air-gaps between the needle point and the conductive surface. The conductive surface is of sufficient extent in relation to the position of the electrode to shield the electrode from any external surface at earth potential and thus to ensure that only the required charging current is passed by the electrode. A shielding action is produced by a relatively deep conical form which also allows a high flow rate. For a frustro-conical surface of apical angle 60.degree. a ratio of end radii in the range 0.85 to 0.
    Type: Grant
    Filed: July 30, 1981
    Date of Patent: December 27, 1983
    Assignee: National Research Development Corporation
    Inventors: Arthur J. Arnold, Barry J. Rye