Method and apparatus for separating low micron size particles

Claim 1

AN IMPROVED CENTRIFUGAL AIR SEPARATOR INCLUDING AN OUTER CASING SEALED AGAINST ATMOSPHERE, A SEALED INNER CASING FORMING AN INNER CHAMBER ARRANGED WITHIN THE OUTER CASING AND SPACED FROM THE WALLS OF THE OUTER CASING TO PROVIDE A SPACE THEREBETWEEN FORMING AN OUTER CHAMBER, AN ANNULAR DISCHARGE PORT FORMED IN THE UPPER PORTION OF THE INNER CHAMBER AND FORMING THE SOLE COMMUNICATION BETWEEN THE CHAMBER OF THE INNER CASING AND THE SPACE BETWEEN THE INNER AND OUTER CASINGS, A FEED INLET LOCATED AT THE TOP OF THE OUTER CASING AND EXTENDING INTO THE INNER CASING FOR INTRODUCING A FINELY DIVIDED MATERIAL INTO SAID INNER CASING, SAID FEED INLET INCLUDING A SEALING MEANS TO PREVENT COMMUNICATION WITH THE ANNULAR SPACE BETWEEN THE INNER AND OUTER CASINGS AND THE FEED MEANS, A ROTATABLE DISTRIBUTOR PLATE ARRANGED IN THE UPPER PART OF THE INNER CASING AND BELOW SAID INLET TO RECEIVE MATERIAL FROM THE FEED INLET AND CENTRIFUGALLY DISPLACE THE MATERIAL WITHIN THE INNER CASING TO PROVIDE A SEPARATION OF RELATIVELY FINE AND RELATIVELY COARSE PARTICLES OCCURRING AS A FALLING MASS FROM SAID FEED INLET, A POWER DRIVEN SUCTION FAN MOUNTED FOR ROTATION WITH THE DISTRIBUTOR PLATE AND LOCATED IN THE OUTER CASING ADJACENT SAID ANNULAR DISCHARGE PORT IN THE INNER CASING TO INDUCE FLOW OF AIR UPWARDLY THROUGH THE FREE FALLING MASS OF PARTICLES THROUGH SAID ANNULAR PORT AND INTO THE ANNULAR SPACE DEVICE MOUNTED BETWEEN OUTER CASINGS, A ROTATING SIZING DEVICE MOUNTED BETWEEN THE DISTRIBUTOR PLATE AND THE SUCTION FAN AND WITHIN SAID INNER CASING FOR SIMULTANEOUS ROTATION WITH SAID DISTRIBUTOR PLATE AND FAN, AN AIR INLET EXTENDING THROUGH THE OUTER CASING AND INTO THE INNER CASING AND SEALED FROM COMMUNICATION WITH THE SPACE BETWEEN THE INNER AND OUTER CASINGS FOR DIRECTING A CURRENT OF AIR INTO THE INNER CASING IN A DIRECTION TO INTERCEPT THE MATERIAL CASCADING FROM THE SAID DISTRIBUTOR PLATE, A TUBULAR OUTLET LOCATED AT THE TOP OF THE OUTER CASING IN TANGENTIAL