Electrostatic spraying device and a method of electrostatic spraying
AssigneeQueen Mary & Westfield College
InventorsJohn P. W. Stark, Matthew S. Alexander, Mark D. Paine, Kate L. Smith
Life of this patent
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Abstract
An electrostatic spraying device (1) and method for dispensing a controlled volume of liquid in pulses using an emitter (2) having a spray area (29) from which the liquid can be sprayed, a means for injecting charges into the liquid, whereby, in use, the liquid (3) is delivered to the spray area by electrostatic forces and electrostatic spraying occurs in one or more pulses whilst the charges are injected. The charges may be injected by a time-varying or constant non-zero electric field so that electrospray occurs above a threshold value.
Claims14
An electrostatic spray apparatus for dispensing a controlled volume of substantially non-conductive liquid in pulses onto a substrate,
- the apparatus comprising:
- an emitter having a spray area from which the liquid can be sprayed,
- an electrode having an aperture;
- a charge injector for being in fluid communication with the liquid and for injecting charges into the liquid, whereby, in use, the liquid is delivered to the spray area by electrostatic forces and electrostatic spraying occurs in uniform pulses through the aperture of the electrode and on to the substrate whilst the charges are injected;
- and
- a controller configured to apply a constant, non-pulsed voltage between the emitter and the electrode, the non-pulsed voltage being operable to provide the uniform pulses of a period independent of the time for which the voltage is applied.
A method of electrostatic spraying for dispensing a controlled volume of substantially non-conductive liquid in pulses onto a substrate, the method comprising:
- providing an emitter for receiving the substantially non-conductive liquid, the emitter having a spray area from which liquid can be sprayed,
- providing an electrode having an aperture;
- injecting charges into the liquid by a change injector in fluid communication with the liquid;
- whereby the substantially non-conductive liquid is delivered to the spray area by electrostatic forces and electrostatic spraying occurs in uniform pulses through the aperture of the electrode and on to the substrate whilst the charges are injected,
- wherein a controller applies a constant, non-pulsed voltage between the emitter and the electrode such that the period of the uniform pulses is independent of the time for which the voltage is applied.
Dependencies are inferred from the claim text.