초록 ▼

A spray gun for applying powder to coat a work piece uses triboelectric and optionally a corona discharge electrode to charge powder particles electrostatically. The gun communicates with a source of pressurized air through a handle with an air valve controlling flow of the air. Powder in a containe

A spray gun for applying powder to coat a work piece uses triboelectric and optionally a corona discharge electrode to charge powder particles electrostatically. The gun communicates with a source of pressurized air through a handle with an air valve controlling flow of the air. Powder in a container in fluid communication with the air flow is fluidized and entrained when the valve is opened. A nozzle with an internal surface defining a passageway to an open end communicates with the powder container. The internal surface of the nozzle frictionally imparts a net electrical charge of a first polarity to part of the powder by frictional contact during spraying. A plurality of discrete tubes are disposed in the central passageway and impart a net electrical charge of a second polarity to another part of the powder due to frictional contact as that part flows around and through the tubes. The powder then exits the nozzle, passes the corona discharge electrode which produces a corona that charges the powder with an electrical potential in the range from about 8 kV to about 20 kV.

대표청구항 ▼

[ What is claimed is:] [1.] A gun for spraying a powder onto a work piece to form a coating, said gun comprising:means for manipulating said gun and for controlling a flow of air from a pressurized source through said gun;a container disposed in fluid communication with said means for manipulating a

[ What is claimed is:] [1.] A gun for spraying a powder onto a work piece to form a coating, said gun comprising:means for manipulating said gun and for controlling a flow of air from a pressurized source through said gun;a container disposed in fluid communication with said means for manipulating and controlling, wherein said powder is held and fluidized by the flow of air from said pressurized source;means defining a flow path through said gun, having an internal surface and an open end, said powder container being releasably fastened to said gun in fluid communication with said flow path, and said internal surface frictionally imparting a net electrical charge of a first polarity to a first portion of said powder when said first portion of said powder contacts said surface during said spraying; and,a plurality of discrete members disposed within said flow path and capable of imparting a net electrical charge of a second polarity to a second portion of said powder when said second portion of said powder contacts said members during said spraying.