Unipolarity powder coating systems including improved tribocharging and corona guns

摘要

A plurality of unconventional negative tribo-charging materials are described for use as the powder contact surfaces in tribocharging and corona powder spray guns, gun compounds, and powder delivery system components. The invention also provides a short barrel tribo-charging powder spray gun having an interchangeable powder contact insert and nozzle, with turbulence inducing air jets. The invention further provides novel tribocharging and corona gun designs. Improved powder coating systems are made possible wherein, for example, negative tribo guns can be utilized with negative corona guns to coat different parts of the same workpiece in a powder coating system and to realize a repair coating process. Also proived is an inside-out configuration in which pressurized air directs powder coating material outward towards a charging surface. Additional configurations provide airjet induced tribocharging and conventional tribocharging portions combined in a single gun.