Abstract: In an electrostatic spray coating method liquid coating material is applied to a workpart inside of a spray booth (12). Alternating flows of liquid coating material, liquid solvent and air are conducted through various internal flow passages in a conduit (14) inside the spray booth. An electronic differentiator (24) is positioned adjacent a predetermined location along the conduit (14) and energized from an electrical source disposed outside of the spray booth (12) to differentiate between the dielectric differences of liquid and gas in the internal flow passage for nonintrusively detecting when the head of liquid flow reaches the predetermined location along the internal flow passage. This is accomplished by an electromagnetic field extending into the flow passage and sensing the changes in the electromagnetic field resulting from dielectric differences between liquid and gas in the flow passage.

Abstract: In an electrostatic spray coating apparatus (10), liquid coating material is applied to a workpart inside of a spray booth (12). Alternating flows of liquid coating material, liquid solvent and air are conducted through various internal flow passages in a conduit (14) inside the spray booth. An electronic differentiator (24) is positioned adjacent a predetermined location along the conduit (14) and energized from an electrical source disposed outside of the spray booth (12) to differentiate between liquid and gas in the internal flow passage for nonintrusively detecting when the head of liquid flow reaches the predetermined location along the internal flow passage. This is accomplished by an electromagnetic field extending into the flow passage and sensing the changes in the electromagnetic field resulting from dielectric differences between liquid and gas in the flow passage.

Abstract: A spray coating apparatus (10) for applying flammable liquid coating material onto a work part (12), including an enclosed spray booth (14) for containing the sprayed flammable coating material in an isolated zone, an atomizer (18) positioned in the spray booth (14) for spraying the coating material onto the work part (12), and a color changer (28) disposed in the spray booth (14) and operated by pneumatic valves (24) for selecting the color of coating material to be supplied to the atomizer (18). Compressed air is supplied from a source outside the spray booth (14) to each of the pneumatic valves (24) on the color changer (28). Intrinsically safe electric solenoid valves (38) are disposed in the spray booth (14) for controlling the compressed air sent to particular pneumatic valves (24) at the color changer (28) so that the proper color of coating material is quickly fed to the atomizer and so that the apparatus (10) can be quickly assembled at locations remote from the place of manufacture.

Abstract: A high-voltage electrostatic painting apparatus (10) for coating an article (12) inside a spray booth (14). The apparatus (10) includes a flow rate meter (34) disposed within the electrostatic environment for measuring the rate at which paint is supplied to a discharge atomizer (18). The meter (34) includes two intermeshing rotors (44, 46) disposed within a sealed non-ferromagnetic housing (54). The two rotors (44, 46) rotate in response to liquid paint flowing through the housing (54). A magnetic coupling (64) acts through the housing (54) to drive an optical signal producing disc (62). A pick-up sensor (82) senses the optical signal from the disc (62) and sends that signal outside the booth (14) to a master control unit (40) via a fiber optic conductor (90). The master control unit (40) automatically adjusts a flow rate regulator valve (92) to provide a constant rate of paint flow to the discharge atomizer (18).

Abstract: A tack-off assembly (10) includes a support structure (12) defining a path (14) extending therethrough. A rotatable axle (16) is mounted from the support structure (12) defining an axis A. A feather duster assembly (18) is mounted on the axle (16) for removing dust particles by contacting the surface of an object (20) traveling along the path (14). The feathers (98) of the feather duster assembly (18) are mounted on a plurality of hubs (24) which are expandable for selectively expanding and contracting the length of the feather assembly (18) along the axis A.