Transfer of granular solids

Claim 1

IN A PROCESS INVOLVING THE PASSAGE OF PARTICULATE SOLIDS THROUGH A SYSTEM CONTAINING FLUID AND INCLUDING UPPER AND LOWER ZONES COMMUNICATING WITH EACH OTHER THROUGH A CONSTANTLY OPEN PASSAGEWAY OF RESTRICTED CROSS SECTIONS, THE METHOD OF TRANSFERRING THE SOLIDS BETWEEN THE TWO ZONES WITHOUT SUBSTANTIAL NET FLOW OF FLUID THEREBETWEEN WHICH COMPRISES MAINTAINING A CONTINUOUS BODY OF FLUID THROUGHOUT SAID ZONES, PASSING THE SOLIDS THROUGH THE FIRST OF SAID ZONES IN THE FORM OF PARTICLES GRAVITATING THROUGH THE FLUID, PASSING A MIXTURE COMPRISING A LOOSE MASS OF SOLID PARTICLE AND FLUID AS A FREELY GRASVITATING STREAM THROUGH THE PASSAGEWAY INTO THE SECOND ZONE, THEREIN SEPARATING FLUID FROM THE SOLID PARTICLES, AND RETURNING THE FLUID AS A SEPARATE STREAM BACK TO SAID FIRST ZONE IN AMOUNT EQUIVALENT TO THE AMOUNT OF FLUID PASSING FROM THE FIRST ZONE TO THE SECOND ZONE, SUCH RETURN BEING EFFECTED SOLELY BY UTILIZING AS ITS DRIVING FORCE THE KINETIC ENERGY OF THE GRAVITATING SOLID PARTILCES, AND REGULATING THE RATE OF TRANSFER OF SOLIDS BETWEEN SAID ZONES BY VARIABLY REGULATING THE RATE OF RETURN OF THE SEPARATE FLUID.