Electrostatic spraying installation for water-based paint

Abstract

An electrostatic spraying installation for low-resistivity paint comprises a conveyor which conveys large objects such as automobile bodies, to be painted with a substantially constant distance between their respective leading edges. A plurality of sprayers is positioned to paint respective specific parts of the objects as they are conveyed past the sprayers by the conveyor. A respective spray member in each sprayer is connected to a high-tension electrical supply. All the spray members are substantially situated in a common plane perpendicular to the path of movement of the objects along the conveyor or in a plurality of planes perpendicular to this path and spaced from each other by the previously mentioned substantially constant distance. A plurality of electrically grounded closed loop primary paint circulation circuits each contain paint of a respective color different than the color of the paint in each of the other primary circuits. A plurality of intermediate storage tanks electrically insulated from ground, equal in number to the primary circuits, are each assigned to a respective primary circuit. An arrangement for selectively connecting each intermediate storage tank to the respective primary circuit is provided and a plurality of selector valves connects each intermediate storage tank selectively to the sprayers. A control system operates the selective connection arrangement or a subset thereof only when none of the spray members is connected to the high-tension supply. Under this condition, the control system operates paint change units simultaneously when all the sprayers are facing the spaces between the objects.