Electrostatic powder spray gun nozzle

In an electrostatic powder spray coating gun including a barrel having an open forward end from which powder coating material is emitted and is electrically charged, a first passage through the wall thereof adapted to be connected to a source of fluidized powder coating material to be emitted from the gun, a second passage through the wall thereof adapted to be connected to a source of gas under pressure, and a high voltage electrical path therein adapted to be connected to a source of high voltage electrical power, the improvement comprising a nozzle assembly comprising:

• a support tube mounted generally axially in said barrel and having a forward end extending out of the open forward end of the barrel,
• a sleeve surrounding said support tube and defining therewith a generally central axial gas flow passageway, said gas flow passageway communicating with said second passage through the wall of said barrel, said sleeve terminating in an open end at said open forward end of said barrel from which pressurized gas issues,
• a nozzle mounted in the open forward end of said barrel and surrounding at least a portion of said sleeve and defining therewith a generally annular powder coating material passageway encircling said gas flow passageway through which powder coating material is emitted, said powder coating material passageway communicating with said first passage through the wall of said barrel,
• a gas deflector cap mounted on the forward end of said support tube having a planar deflecting surface spaced from said open end of said sleeve for deflecting said pressurized gas issuing out of said open end of said sleeve radially outwardly, the outer dimension of said gas deflector cap being no greater than the inner dimension of said coating material passageway where said powder coating material is emitted from said nozzle and said gas deflector cap being so located with respect to said nozzle that said radially outwardly moving stream of pressurized gas impacts said powder coating material within the confines of said nozzle to produce a conical spray pattern of powder coating material issuing from said nozzle, and
• a charging electrode in said support tube having one end extending out the forward end thereof and beyond said gas deflector cap and the other end thereof connected to said high voltage electrical path.