Apparatus for and improved method of thickening

Claim 1

THE METHOD OF THICKENING A SUSPENSION OF SOLIDS CARRIED IN A LIQUID, WHICH METHOD COMPRISES INTRODUCING THE SUSPENSION INTO A TANK WITH FINELY DIVIDED AIR BUBBLES AND RETAINING THE SUSPENSION IN THE TANK UNTIL A FLOATING BLANKET IS FORMED HAVING A SUBSTANTIAL DEPTH AND AN UPPER LAYER DISPOSED ABOVE THE LIQUID LEVEL AND UNTIL THE SOLIDS CONCENTRATION OF SAID UPPER LAYER REACHES THE RANGE WHERE THE CORRESPONDING VISCOSITY VARIES SUBSTANTIALLY SO THAT THE THICKER PARTS OF SAID UPPER LAYER HAVING A HIGHER SOLIDS CONCENTRATION HAVE A CONSIDERABLY HIGHER VISCOSITY AND THE THINNER PARTS OF SAID UPPER LAYER HAVING A RELATIVELY LOWER SOLIDS CONCENTRATION HAVE A CONSIDERABLY LOWER VISCOSITY, THEREAFTER MOVING AND ROTATING A ROLL HAVING A SMOOTH SURFACE TO PLACE SAID SURFACE IN AND OUT OF CONTACT WITH SUCCESSIVE PORTIONS OF THE UPPER SURFACE OF SAID UPPER LAYER TO WITHDRAW THE THICKER PARTS THEREOF IN GREATER QUANTITY AND AT A FASTER RATE RELATIVE TO THE QUANTITY AND RATE OF WITHDRAWAL BY THE ROLL OF THE THINNER PARTS OF SAID UPPER LAYER BY REASON OF SAID DIFFERENCES IN VISCOSITY, AND COLLECTING THE MATERIAL REMOVED BY THE ROLL WHICH MATERIAL WILL THEREBY HAVE A CONCENTRATION SUBSTANTIALLY GREATER THAN THE GENERAL AVERAGE CONCENTRATION OF SAID UPPER LAYER.

Claim 2

THE METHOD OF THICKENING A SUSPENSION OF SOLIDS CARRIED IN A LIQUID, WHICH METHOD COMPRISES INTRODUCING THE SUSPENSION INTO A TANK WITH FINELY DIVIDED AIR BUBBLES AND RETAINING THE SUSPENSION IN THE TANK UNTIL A FLOATING BLANKET IS FORMED HAVING A SUBSTANTIAL DEPTH AND AN UPPER LAYER DISPOSED ABOVE THE LIQUID LEVEL AND UNTIL THE SOLIDS CONCENTRATION OF SAID UPPER LAYER REACHES THE RANGE WHERE THE CORRESPONDING VISCOSITY VARIES SUBSTANTIALLY SO THAT THE THICKER PARTS OF SAID UPPER LAYER HAVING A HIGHER SOLIDS CONCENTRATION HAVE A CONSIDERABLY HIGHER VISCOSITY AND THE THINNER PARTS OF SAID UPPER LAYER HAVING A RELATIVELY LOWER SOLIDS CONCENTRATION HAVE A CONSIDERABLY LOWER VISCOSITY, THEREAFTER MOVING AND ROTATING A ROLL HAVING A SMOOTH SURFACE TO PLACE SAID SURFACE IN AND OUT OF CONTACT WITH SUCCESSIVE PORTIONS OF THE UPPER SURFACE OF SAID UPPER LAYER TO WITHDRAW THE THICKER PARTS THEREOF IN GREATER QUANTITY AND AT A FASTER RATE RELATIVE TO THE QUANTITY AND RATE OF WITHDRAWAL BY THE ROLL OF THE THINNER PARTS OF SAID UPPER LAYER BY REASON OF SAID DIFFERENCES IN VISCOSITY, AND COLLECTING THE MATERIAL REMOVED BY THE ROLL WHICH MATERIAL WILL THEREBY HAVE A CONCENTRATION SUBSTANTIALLY GREATER THAN THE GENERAL AVERAGE CONCENTRATION OF SAID UPPER LAYER.