Electrostatic spraying apparatus wherein the liquid supply to the spray nozzle 20 is via a mechanical valve operated by an actuating member 12. Actuating member 12 is connected to a remote operating lever 3, which is preferably electrically conductive, via a connecting member 41 including an elastically extensible portion, e.g. a spring 39. Connecting member 41 is electrically conductive thus providing an electrical connection from lever 3 to the spray head.
In an electrostatic particle spraying apparatus, a hand-held triggering mechanism is provided with a self-contained source of high D.C. voltage and a coupling sleeve into which a conventional aerosol spray can is inserted. A trigger mechanism is squeezed by a mechanism operator and closes a switch that completes an electrical connection between the D.C. voltage source and an electrode of the mechanism, creating an electric potential in the electrode. The electrode is positioned in the projected path of particle spray from the aerosol can, and continued depression of the trigger lever causes a hammer to contact and depress a nozzle tip of the aerosol can, releasing the pressurized fluid contents of the can from the nozzle tip in a projected path of particle spray. A distal end of the electrode extends into the projected path of particle spray. The electric potential of the electrode induces an electric charge of predetermined polarity in the spray of particles dispensed from the nozzle tip of the aerosol can thereby enhancing the atomization of the particles of spray and enhancing the depositing of the particles of spray on a grounded substrate surface.
An actuator for electrically charging an aerosol spray has an inductor located adjacent to the spray nozzle to induce a charge on the atomized fluid. Charge to the inductor is provided by a piezoelectric crystal which is stressed by movement of an operating member to open the spray valve. Inductor charging utilizes negligible electrical power so that additional power sources are not required. The crystal may be stressed continuously such as by squeezing, or intermittently, such as by striking. When an intermittent stressing is utilized, the electrical circuit includes a switch between the crystal and inductor which is opened as the valve is opened to isolate electrically the inductor during spraying.