Electrostatic spray method

Abstract

An electrostatic spray apparatus and method for spraying electrically conductive coating materials on a continuous basis from an electrically grounded bulk coating supply. Included is a spray gun from which electrostatically charged coating material is emitted toward an electrically grounded object to be coated; a high voltage source for electrostatically charging the coating material emitted from the gun; an electrically grounded bulk coating storage tank; and an intermediate tank assembly including a) an inner tank for continuously supplying coating to the gun via a hose, which inner tank is automatically and periodically replenished with coating material from the grounded bulk supply tank without establishing an electrically conductive path between the electrically grounded bulk storage tank and the inner tank which contains coating material electrostatically charged via the column of conductive coating material in the gun hose, b) an electrically grounded outer housing or container completely enclosing the inner tank, and c) an insulative support electrically isolating the inner tank from the outer grounded container, which support is subjected to a gaseous stream to prevent build-up thereon of a conductive film of coating material which, if permitted to occur, would shortcircuit the grounded outer container to the electrostatically charged coating material stored in the inner tank and thereby destroy the electrical isolation between the inner tank and the grounded outer container.

Dependencies are inferred from the claim text.