Patent ID: 6488773
Filing Date: 2002-12-03
Classification: B05B

Abstract:
A thermal spray apparatus for coating a substrate with a polymer coating material, the thermal spray apparatus comprising:a) a source of pressurized molten polymer coating material; b) a source of pressurized hot gas for generating a flowstream; and c) a spray head having: i) an input coating passage, the input coating passage in fluid communication with the source of pressurized molten polymer coating material, ii) an input air passage, the input air passage in fluid communication with the source of pressurized hot gas, and iii) a nozzle assembly for directing the flowstream towards the substrate, the nozzle assembly having a spray surface, a hot air receiving chamber in fluid communication with the input air passage, a plurality of air delivery conduits extending from the hot air receiving chamber to the spray surface to define a plurality of air orifices in the spray surface, and a coating material conduit extending from the input coating passage to the spray surface to define a material orifice in the spray surface, wherein the coating material conduit has a longitudinal axis, wherein each air delivery conduit has a longitudinal axis, wherein the plurality of air delivery conduits are inclined and skewed with respect to the longitudinal axis of the coating material conduit, wherein the molten polymer exits the material orifice along an axis co-axial to the longitudinal axis of the coating material conduit, wherein each of the air delivery conduits has a major direction component in a direction radially inwardly with respect to the longitudinal axis of the coating material conduit, the radially inwardly component being skewed with respect to the radial direction of the it longitudinal axis of the coating material conduit so that hot gas discharges from the plurality of air orifices avoid the axis of the exiting molten polymer, and wherein the plurality of air orifices at least partially surround a portion of the material orifice, so that, when the pressurized hot gas exits the plurality of air orifices and the pressurized coating material exits the material orifice, the coating material is atomized and transported to the substrate in a molten state.