Electrostatic separating apparatus for particles

Claim 1

A separating apparatus for transferring both conductive and nonconductive powder particles of the type which are capable of movement in an electric field, the apparatus comprising a plurality of apertured screen electrodes, each having different size mesh apertures; a plurality of basic electrodes, each mounted a spaced, predetermined distance below a screen electrode; means for applying a predetermined transfer potential between said electrodes thereby establishing an electric field between each pair of electrodes; conveying means connected to and including the plurality of base electrodes including a conveying plate attached to the plurality of base electrodes; means supplying the powder particles to the conveying means; vibration means connected to said conveying plate wherein the conveying plate is reciprocated causing travel of the particles to successive electrode pairs; and means for conveying a carrier fluid immediately above each screen electrode, including a channel means having an input on one side of a screen electrode and an output on the other side to direct gas transversely across one side of the screen electrode with a minimum of disturbance of the particle travel between the screen electrode and the base electrode, whereby various size particles are delivered to the conveying means and enter the electric field of an electrode pair and are projected toward said screen electrodes, the particles compatible to the particle screen aperture passing through the appropriate screen electrode due to their momentum and being conveyed from the screen electrode by the carrier fluid, larger particles being blocked and passed along the conveying means to the next electrode pair.