Method of and apparatus for air classification

Claim 1

A METHOD OF SEPARATING LIGHTER TOBACCO PARTICLES FROM HEAVIER TOBACCO PARTICLES WHICH FORM A MIXTURE WITH THE LIGHTER PARTICLES, COMPRISING THE STEPS OF INTRODUCING THE MIXTURE OF LIGHTER AND HEAVIER PARTICLES INTO AN ASCENDING INCLINED FIRST AIR STREAM HAVING AN UPPER AND LOWER SURFACE SAID STREAM BEING STRONG ENOUGH TO ENTRAIN THE MAJOR PART OF LIGHTER PARTICLES BUT TOO WEAK TO ENTRAIN ALL HEAVIER PARTICLES SO THAT THE MAJOR PART OF HEAVIER PARTICLES DESCENDS BY GRAVITY, THAT THE MAJOR PART OF LIGHTER PARTICLES ASCENDS WITH THE FIRST AIR STREAM AND THAT THE REMAINDER OF THE MIXTURE TENDS TO ACCUMULATE ABOVE SUCH SECTION OF SAID STREAM FROM WHICH THE MAJORITY OF HEAVIER PARTICLES DESCENDS BY GRAVITY DEFLECTING A PORTION OF SAID INCLINED FIRST AIR STREAM FROM SAID UPPER SURFACE AND AT AN ANGLE TO THE DIRECTION OF