An electrostatic powder coating apparatus including a housing with an interior
coating area for receiving a workpiece. The interior coating area includes a vortex
inducing surface and a pressurized air input device directs air against the surface
to form a swirling pattern of air around the workpiece. A powder introducer directs
charged powder into the swirling pattern of air and the powder is then electrostatically
attracted to the workpiece. The powder introducer may be a powder fluidizing bed
disposed in the housing or other suppliers, such as electrostatic powder spray
guns. In alternative embodiments, vortex generators in the form of tubular structures
connected proximate the housing inlet and outlet have tangential ports for introducing
positive pressure air or inducing vacuum in the tubular structures. These also
form a swirling pattern of air which may be used to produce or augment the swirling
pattern in the coating area or used to collect excess powder while augmenting the
coating at the inlet and outlet.
