Sifter of the circulating air type

Claim 1

SIFTING APPARATUS OF THE CIRCULATING AIR TYPE COMPRISING AN OUTER HOUSING HAVING A MATERIAL INTAKE, AN INNER HOUSING AND A CYCLONE ARRANGED CENTRALLY OF SAID HOUSINGS, SAID CYCLONE DEFINING A SEPARATOR FOR FINE SUBSTANCES AND FOR GRIT AND HAVING A DISCHARGE APERTURE AT ITS LOWER END FOR FINE SUBSTANCES, A BAFFLE ARRANGED IN AND DEFINING AN AIR GAP WITH SAID INNER HOUSING ABOVE SAID CYCLONE AND DIVIDING SAID INNER HOUSING INTO AN UPPER CENTRIFUGAL SEPARATING SPACE AND A LOWER GRIT DISCHARGING CHAMBER AND AIR CIRCULATING SPACE FOR THE UPWARD FLOW OF AIR, SAID OUTER HOUSING HAVING A GRIT DISCHARGE APERTURE DISPOSED BELOW AND IN RECEIVING RELATION TO SAID DISCHARGING CHAMBER AND SAID INNER HOUSING HAVING AN OPEN UPPER END IN AIR CIRCULATING RELATIONSHIP WITH SAID OUTER HOUSING, THE WALLS OF SAID INNER AND SAID OUTER HOUSING DEFINING AN AIR CIRCULATING SPACE FOR DOWNWARD FLOW OF AIR, A CENTRAL AIR SHAFT ARRANGED CENTRALLY IN THE UPPER END OF SAID CYCLONE, DISPERSING MEANS ARRANGED IN SAID DISCHARGING CHAMBER AROUND SAID CYCLONE AND BELOW SAID MATERIAL INTAKE, A SIFTING SHEEL ROTATABLY MOUNTED ABOVE SAID CYCLONE AT THE UPPER END OF SAID LOWER GRIT DISCHARGING CHAMBER AND AIR CIRCULATING SPACE, A BLOWER WHEEL ROTATABLY MOUNTED ABOVE SAID BAFFLE IN SAID CENTRIFUGAL SEPARATING SPACE, AND MEANS FOR ROTATING SAID SIFTING WHEEL AND SAID BLOWER WHEEL TO CIRCULATE AIR FLOW THROUGH THE UPPER END OF SAID CYCLONE, SAID AIR SHAFT, SAID BLOWER WHEEL UPWARDLY THEREFROM INTO AND DOWNWARDLY IN SAID AIR CIRCULATING SPACE, UPWARDLY IN SAID CHAMBER THROUGH SAID DISPERSING MEANS TO SAID SIFTER AND SAID CYCLONE.