Patent ID: 7055768

Claim:
An electrostatically controlled device for transmitting a beam of material in particulate form at a target surface to be coated, said device comprising: an outer bell-shaped member which is rotatable about a principal axis and arranged to project a conical curtain of small particles flowing generally towards said target surface; a supply system for supplying material from a reservoir source towards a peripheral internal shaping region of said outer bell-shaped member; an inner rotary bell-shaped member provided coaxially with said outer bell-shaped member and arranged to rotate differently to said outer bell-shaped member so that at least a major part of the material supplied by said supply system is subject to differing rotary forces imparted by the inner and outer rotary bell-shaped members; and a centrally located rotary diffuser disc for transmission of said material from said supply system to the inner rotary bell-shaped member, said disc having at least one aperture therethrough so that some of said material supplied by said supply system can pass through said aperture and onto an external face of said disc so as to be forced outwards centrifugally towards the outer bell-shaped member.