Air classifier

Claim 1

Apparatus for separating a heterogeneous mixture of heavy and light particles into heavier and lighter fractions comprising: a generally horizontal passageway; means for introducing and guiding a pressurized primary air flow into one end area of the passageway and discharging said primary air flow from the other end area of the passageway to thereby induce a horizontal primary air flow longitudinally through the passageway at a predetermined velocity; an air deck including at least first and second air deck portions, said first portion being upstream of said second portion, each air deck portion having an upper surface extending along a portion of the bottom area of the passageway and deck air conduits arranged to introduce and guide deck air flow through the deck upper surface into the passageway with both horizontal and vertical components of motion, the horizontal component being directed downstream of said passageway; means for supplying deck air under pressure through said deck air conduits; means for introducing a mixture of heavy and light particles into an upper area of said passageway adjacent to and downstream of the horizontal primary air flow introduction area and above said first portion of said air deck; air nozzle means disposed in the bottom area of the passageway adjacent to but downstream of the area of introduction of said mixture of heavy and light particles and upstream of said second air deck portion, said air nozzle means arranged to introduce and guide primary vertical air flow into the passageway independently of said air deck flow across substantially the entire width of the passageway, the primary vertical air flow including a vertical component of motion and constituting a primary vertical air vector, the vertical component of air flow through the air deck constituting a secondary vertical air vector; means for supplying air flow under pressure to said air nozzle means; heavy fraction particle deflector means disposed downstream of said second air deck portion and having an upper area extending a predetermined distance above a horizontal plane that includes air deck upper surface; means for collecting and removing from the passageway deflected heavy fraction particles; means located entirely downstream of said heavy fraction particle deflector means for discharging air flows from the passageway that have been introduced through the nozzle and the air deck; means located entirely downstream of said heavy fraction particle deflector means for collecting and removing from the passageway light fraction particles; whereby heavy and light particles introduced into the passageway are caused to become and remain vertically stratified while moving horizontally through the passageway under the influence of air flows within the passageway, and are caused to become separated into heavier and lighter fractions prior to their sequential downstream collection and removal from the passageway.