Abstract: A spray gun with electrokinetic charging of powdered material for the purpose of electrostatically coating workpieces with a powder coating. As the powder flows pneumatically through a channel of insulation material in the form of an annular gap, the plastic powder to be applied is charged by superimposition of triboelectric effects with ionization processes initiated by these effects at a passive ionizer electrode, and completed by friction against a semiconductive insert within the annular gap. Thus, the effective area of the electrostatic induction ionizer is expanded, the charge on the powder is increased and spark-like sliding discharges in the flow channels as well as dielectric breakdowns of the channel wall are prevented.

Abstract: An apparatus for the electro-kinetic charging of powder-like materials having a pair of supply channels, an input zone for each channel, one for the powder dispersed in a gas flow and one for another gas flow and which are shaped as dual annular nozzles with a pipe-shaped separating wall therebetween acting as an electrostatic ionizing electrode and made from an electrically semiconductive material having anti-sticking properties and, wherein the adjoining flow channel is formed as an annular channel by a pipe from an insulating material, and a centrally arranged rod, wherein the ratio between rod and pipe diameters is on the range from 0.75 to 0.9.