Tribocharge applicator device

Abstract

A tribocharge applicator device for application of a powdered material to a substrate is disclosed. The device includes an inlet for pressurized conveying gas, an inlet for powdered polymeric material having a first dielectric constant, a mixing chamber, a discharge barrel and a charge module. The charge module includes: at least two spiral charging elements disposed inside and coaxially aligned with respect to the barrel, each spiral charging element comprising an elongated sheet of a different material having a second dielectric constant. The proximal end of the elongated sheet is twisted about its longitudinal axis with respect to the distal end such that each longitudinal edge of the sheet forms a spiral. Each charging element is positioned within the barrel adjacent to another like element such that a distal end of a first element abuts a proximal end of a second element wherein the first charging element defines a first spiral flow path and said second charging element defines a second spiral flow path rotationally opposite to the first spiral flow path. An electric charge is transferred to the powdered polymeric material as the powdered material flows through the charging element.