Method and apparatus for centrifugally separating finely divided solids from aqueous suspensions thereof

Claim 1

A METHOD OF CENTRIFUGALLY SEPARATING FINELY DIVIDED SOLIDS FROM AN AQUEOUS SUSPENSION THEREOF, COMPRISING: A. FEEDING THE AQUEOUS SUSPENSION SUBSTANTIALLY TANGENTIALLY INTO A CYLINDRICAL CASING OF A BLENDER AND SWIRLING THE AQUEOUS SUSPENSION IN A CYLINDRICAL, OPEN ENDED VORTEX FINDER IN THE CYLINDRICAL CASING TO FORM, AS A THIN FLOWING SHEET OF THE AQUEOUS SUSPENSION WITH THE FINELY DIVIDED SOLIDS HAVING WETTED SURFACES FROM THE AQUEOUS MEDIUM, A SWIRLING HOLLOW CONE IN THE VORTEX FINDER FLOWING AROUND A RIM OF THE VOTEX FINDER, B. SPRAYING, AS A CONICAL SPRAY, A SOLUTION OF A WATER SOLUBLE HIGH MOLECULAR WEIGHT LONG CHAIN FLOCCULANT SUBSTANTIALLY AT RIGHT ANGLES, WITH THE KINETIC ENERGIES OF SPRAYED FLOCCULANT AND THAT OF FLOWING SHEET FLOWING AROUND THE RIM OF THE VORTEX FINDER MATCHED, TOWARDS A SIDE FACE OF ALL OF THE PORTION OF THE FLOWING SHEET FLOWING AROUND THE RIM OF THE VORTEX FINDER SO THAT THE FLUCCULANT IS SPRAYED INTO THE FLOWING SHEET FLOWING AROUND THE RIM OF THE VOTEX FINDER AND THE FLUOCCULANT AND AQUEOUS SUSPENSION ARE RAPIDLY AND INTENSIVELY INTERSPERSED AND THE FLOCCULANT IS ADSORBED ONTO THE WETTED SURFACES OF THE FINELY DIVIDED SOLIDS WITHOUT TOTALLY WRAPPING INDIVIDUAL FINELY DIVIDED SOLIDS BY THE FLOCCULANT MOLECULES AND WITHOUT ENTRAPPING FINELY DIVIDED SOLIDS BY PREMATURE BRIDGING BY THE FLOCCULANT MOLECULES, C. MAINTAINING THE SHAPE OF THE SWIRLING HOLLOW CONE BY PRESSURIZING AIR WITHIN THE SWIRLING HOLLOW CONE WITH AIR FROM A NOZZLE WHICH IS FED WITHIN THE SWIRLING HOLLOW CONE INTO THE HOLLOW CENTER THEREOF IN THE OUTWARDLY TAPERING DIRECTION OF THE SWIRLING HOLLOW CONE SO THAT THE KINETIC ENERGIES OF THE FLOCCULANT AND THAT OF THE AQUEOUS SUSPENSION ARE NOT DISSIPATED BY EDDY CURRENTS AND FLUID MASSES THAT WOULD OTHERWISE TEND TO BE IN THE WAY OF THE INTERSECTION OF THE SPRAYED FLOCCULANT AND THE SWIRLING HOLLOW CONE, D. FEEDING THE AQUEOUS SUSPENSION, WITH THE SAID FLOCCULANT ADSORBED ONTO THE SAID WETTED SURFACES OF THE FINELY DIVIDED SOLIDS, FROM THE BLENDER TO A FLOCCULATOR AND FLOCCULATING THE FINELY DIVIDED SOLIDS, BY MEANS OF THE WATER SOLUBLE FLOCCULANT ADSORBED ONTO THE WETTED SURFACES, SO FROM DENSE, STRONG FLOCS, WHICH ARE PREDOMINANTLY LARGE ENOUGH TO BE SUBSTANTIALLY SEPARATED FROM THE AQUEOUS MEDIUM BY A CYCLONE SEPARATOR, AND E. FEEDING THE DENSE, STRONG FLOCS AND AQUEOUS MEDIUM TO A CYCLONE SEPARATOR AND CENTRIFUGALLY SEPARATING A MAJOR PORTION OF THE DENSE, STRONG FLOCS FROM AT LEAST SOME OF THE AQUEOUS MEDIUM BY MEANS OF THAT CYCLONE SEPARATOR.

Claim 2

A METHOD OF CENTRIFUGALLY SEPARATING FINELY DIVIDED SOLIDS FROM AN AQUEOUS SUSPENSION THEREOF, COMPRISING: A. FEEDING THE AQUEOUS SUSPENSION SUBSTANTIALLY TANGENTIALLY INTO A CYLINDRICAL CASING OF A BLENDER AND SWIRLING THE AQUEOUS SUSPENSION IN A CYLINDRICAL, OPEN ENDED VORTEX FINDER IN THE CYLINDRICAL CASING TO FORM, AS A THIN FLOWING SHEET OF THE AQUEOUS SUSPENSION WITH THE FINELY DIVIDED SOLIDS HAVING WETTED SURFACES FROM THE AQUEOUS MEDIUM, A SWIRLING HOLLOW CONE IN THE VORTEX FINDER FLOWING AROUND A RIM OF THE VOTEX FINDER, B. SPRAYING, AS A CONICAL SPRAY, A SOLUTION OF A WATER SOLUBLE HIGH MOLECULAR WEIGHT LONG CHAIN FLOCCULANT SUBSTANTIALLY AT RIGHT ANGLES, WITH THE KINETIC ENERGIES OF SPRAYED FLOCCULANT AND THAT OF FLOWING SHEET FLOWING AROUND THE RIM OF THE VORTEX FINDER MATCHED, TOWARDS A SIDE FACE OF ALL OF THE PORTION OF THE FLOWING SHEET FLOWING AROUND THE RIM OF THE VORTEX FINDER SO THAT THE FLUCCULANT IS SPRAYED INTO THE FLOWING SHEET FLOWING AROUND THE RIM OF THE VOTEX FINDER AND THE FLUOCCULANT AND AQUEOUS SUSPENSION ARE RAPIDLY AND INTENSIVELY INTERSPERSED AND THE FLOCCULANT IS ADSORBED ONTO THE WETTED SURFACES OF THE FINELY DIVIDED SOLIDS WITHOUT TOTALLY WRAPPING INDIVIDUAL FINELY DIVIDED SOLIDS BY THE FLOCCULANT MOLECULES AND WITHOUT ENTRAPPING FINELY DIVIDED SOLIDS BY PREMATURE BRIDGING BY THE FLOCCULANT MOLECULES, C. MAINTAINING THE SHAPE OF THE SWIRLING HOLLOW CONE BY PRESSURIZING AIR WITHIN THE SWIRLING HOLLOW CONE WITH AIR FROM A NOZZLE WHICH IS FED WITHIN THE SWIRLING HOLLOW CONE INTO THE HOLLOW CENTER THEREOF IN THE OUTWARDLY TAPERING DIRECTION OF THE SWIRLING HOLLOW CONE SO THAT THE KINETIC ENERGIES OF THE FLOCCULANT AND THAT OF THE AQUEOUS SUSPENSION ARE NOT DISSIPATED BY EDDY CURRENTS AND FLUID MASSES THAT WOULD OTHERWISE TEND TO BE IN THE WAY OF THE INTERSECTION OF THE SPRAYED FLOCCULANT AND THE SWIRLING HOLLOW CONE, D. FEEDING THE AQUEOUS SUSPENSION, WITH THE SAID FLOCCULANT ADSORBED ONTO THE SAID WETTED SURFACES OF THE FINELY DIVIDED SOLIDS, FROM THE BLENDER TO A FLOCCULATOR AND FLOCCULATING THE FINELY DIVIDED SOLIDS, BY MEANS OF THE WATER SOLUBLE FLOCCULANT ADSORBED ONTO THE WETTED SURFACES, SO FROM DENSE, STRONG FLOCS, WHICH ARE PREDOMINANTLY LARGE ENOUGH TO BE SUBSTANTIALLY SEPARATED FROM THE AQUEOUS MEDIUM BY A CYCLONE SEPARATOR, AND E. FEEDING THE DENSE, STRONG FLOCS AND AQUEOUS MEDIUM TO A CYCLONE SEPARATOR AND CENTRIFUGALLY SEPARATING A MAJOR PORTION OF THE DENSE, STRONG FLOCS FROM AT LEAST SOME OF THE AQUEOUS MEDIUM BY MEANS OF THAT CYCLONE SEPARATOR.

Claim 6

An apparatus for centrifugally separating finely divided solids from an aqueous suspension thereof, comprising a blender, a flocculator connected to the outlet of the blender, and a cyclone separator connected to the outlet of the flocculator, and wherein the blender comprises a cylindrical casing with a substantially tangential, aqueous suspension inlet, for directing aqueous suspension substantially tangentially into the casing to form a rotating, swirling hollow cone therein, and a substantially tangential outlet, for conveying the rotational flow substantially tangentially out of the casing and at a position spaced along the length of the casing from the inlet, an annular web secured inside the casing and sealed thereto and extending radially inwardly at an intermediate position between the inlet and outlet, a cylindrical, open ended, vortex finder disposed coaxially within the casing and sealed, at an intermediate position along its length, in the annular web, the vortex finder extending from each side of the annular web to positions beyond the inlet and outlet, a flocculant solution nozzle mounted in an end wall of the casing and facing the end of the vortex finder at a position beyond the outlet, the flocculant solution nozzle being shaped to direct a conical spray of flocculant solution substantially at right angles into the hollow cone of aqueous suspension in the vortex finder, and passing from the inlet to the outlet, as it passes around a rim of the vortex finder, an air nozzle coaxially disposed in the vortex finder and facing the flocculant solution nozzle for directing pressurizing air within the swirling hollow cone of the aqueous suspension and the conical spray of flocculant, a tube extending along the interior of the vortex finder and mounting the air nozzle to an opposite end wall of the casing to that in whiCh the flocculant nozzle is mounted, and a source of pressurized air connected to the air nozzle through the tube.

Claim 7

An apparatus for centrifugally separating finely divided solids from an aqueous suspension thereof, comprising a blender, a flocculator connected to the outlet of the blender, and a cyclone separator connected to the outlet of the flocculator, and wherein the blender comprises a cylindrical casing with a substantially tangential, aqueous suspension inlet, for directing aqueous suspension substantially tangentially into the casing to form a rotating, swirling hollow cone therein, and a substantially tangential outlet, for conveying the rotational flow substantially tangentially out of the casing and at a position spaced along the length of the casing from the inlet, an annular web secured inside the casing and sealed thereto and extending radially inwardly at an intermediate position between the inlet and outlet, a cylindrical, open ended, vortex finder disposed coaxially within the casing and sealed, at an intermediate position along its length, in the annular web, the vortex finder extending from each side of the annular web to positions beyond the inlet and outlet, a flocculant solution nozzle mounted in an end wall of the casing and facing the end of the vortex finder at a position beyond the outlet, the flocculant solution nozzle being shaped to direct a conical spray of flocculant solution substantially at right angles into the hollow cone of aqueous suspension in the vortex finder, and passing from the inlet to the outlet, as it passes around a rim of the vortex finder, an air nozzle coaxially disposed in the vortex finder and facing the flocculant solution nozzle for directing pressurizing air within the swirling hollow cone of the aqueous suspension and the conical spray of flocculant, a tube extending along the interior of the vortex finder and mounting the air nozzle to an opposite end wall of the casing to that in whiCh the flocculant nozzle is mounted, and a source of pressurized air connected to the air nozzle through the tube.