Method of controlling spray current and voltage in electrostatic coating apparatus
AssigneeITW Gema AG
InventorFelix Mauchle
Life of this patent
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Abstract
A method of ensuring safety in operation of a coating apparatus includes the steps of measuring an instant value of a spray current, and regulating the spray current so that the spray current does not exceed a predetermined spray current limiting value by adjusting the high voltage applied to an electrode of the apparatus based on the measured instant value of the spray current. The spray current is directly measured in a return path of electrical current from the object to a regulating circuit of the apparatus.
Claims12
A method of ensuring safety in operation of a coating apparatus having a spray nozzle for spraying a coating material onto an electrically conductive object to be coated, at least one electrode for electrostatically charging the coating material sprayed from the spray nozzle, and a voltage source for applying a voltage to the electrode, the voltage causing the electrostatically charged coating material to move towards the object to be coated resulting in a spray current, said method comprising the steps of:
- measuring an instant value of the spray current;
- and
- regulating the spray current so that the spray current does not exceed a predetermined spray current limiting value by adjusting the voltage applied to the electrode based on the measured instant value of the spray current.
A method of ensuring safety in operation of a coating apparatus having a spray nozzle for spraying a coating material onto an electrically conductive object to be coated, at least one electrode for electrostatically charging the coating material sprayed from the spray nozzle, a voltage source for applying a voltage to the electrode, the voltage causing the electrostatically charged coating material to move to the object to be coated resulting in a spray current, and a regulating circuit connected between the voltage source and the object, said method comprising the steps of:
- measuring an instant value of the spray current;
- and
- regulating the spray current so that the spray current does not exceed a predetermined spray current limiting value;
- wherein
- said measuring comprises directly determining the instant value of the spray current in a return path from the object to be coated to the regulating circuit of said apparatus;
- and
- said regulating comprises adjusting the voltage applied to the electrode based on the measured instant value of the spray current.
Dependencies are inferred from the claim text.