Method and apparatus for centrifugal classification

Claim 2

A materials classifying method for a powder material utilizing a housing arrangement having a lower portion comprising a cylindrical member and a downwardly depending conical portion extending from the bottom of said cylindrical member, a hollow conical guide having an upwardly extending apex being positioned in said cylindrical member, and an upper portion comprising a cylindrical member disposed on said first mentioned cylindrical member so as to define a narrow peripheral air inflow space therebetween; said method comprising; blowing a supply of air into said conical portion in tangential relationship to the inner peripheral surface thereof while concurrently guiding said air in a helically upward flow path; concurrently blowing a second tangentially directed flow of air into the upper cylindrical member in a direction corresponding to the tangential flow direction of said first flow of air; concurrently blowing an admixed tangential flow of air and powdery material into said lower cylindrical member along the inner wall thereof in a direction corresponding to the tangential flow direction of said air supply flows, inducing air into said lower portion through said said peripheral air inflow space, guiding said admixed flow along said inner wall upwardly in a subStantially helical path for mixing with said first and second air supply flows and with the air from said peripheral air inflow space, and withdrawing finer material and air from at least portions of said admixture through an upper outlet and conveying the coarser particles towards a lower outlet in said conical portion.

Claim 3

A materials classifier comprising a main body having an essentially upright open ended cylindrical portion and a conical portion depending from the bottom of said cylindrical portion, said conical portion being provided with a helical structure extending along its inner peripheral wall and having a predetermined gradient and width, an air inlet connected to the lower part of said conical portion for tangential air inlet flow, and a discharge port in the lower apex end of said conical portion, said main body portion including an inlet for tangential inflow of an admixture containing powdery material being classified, the direction of tangential flow of which corresponds to the direction of tangential flow through said conical portion; a top body portion of essentially upright cylindrical shape being supported on said main body portion, a central outlet pipe being provided in the upper surface of the inner wall of said top body portion, an inlet for tangential air inlet flow being provided in the side wall of said top body portion, the direction of flow of which corresponds to the direction of flow of said other air and admixture inlets, means defining a narrow peripheral space for permitting inflow of air being provided at the juncture between said main and top body portions; a hollow conical guide having an upwardly projecting apex being positioned in said main body in space relation to the inner peripheral wall thereof and above said conical portion; and a further helical structure of predetermined gradient and width extending along the inner peripheral wall of said main body portion the gradients of said helical structures rising in the direction of flow of said tangential inlets.

Claim 4

A materials classifier comprising a main body having an essentially upright open ended cylindrical portion and a conical portion depending from the bottom of said cylindrical portion, said conical portion being provided with a helical structure extending along its inner peripheral wall and having a predetermined gradient and width, an air inlet connected to the lower part of said conical portion for tangential air inlet flow, and a discharge port in the lower apex end of said conical portion, said main body portion including an inlet for tangential inflow of an admixture containing powdery material being classified, the direction of tangential flow of which corresponds to the direction of tangential flow through said conical portion; a top body portion of essentially upright cylindrical shape being supported on said main body portion, a central outlet pipe being provided in the upper surface of the inner wall of said top body portion, an inlet for tangential air inlet flow being provided in the side wall of said top body portion, the direction of flow of which corresponds to the direction of flow of said other air and admixture inlets, means defining a narrow peripheral space for permitting inflow of air being provided at the juncture between said main and top body portions; a hollow conical guide having an upwardly projecting apex being positioned in said main body in space relation to the inner peripheral wall thereof and above said conical portion; and a further helical structure of predetermined gradient and width extending along the inner peripheral wall of said main body portion the gradients of said helical structures rising in the direction of flow of said tangential inlets.

Claim 5

A classifier as defined in claim 2, wherein a central outlet pipe is connected to the outlet pipe at the inside upper surface of said main body portion, and a discharge flow controlling pipe is slidably positioned interiorly of said outlet pipe.

Claim 6

A classifier as defined in claim 2, including retaining elements positioned about the lower outside peripheral wall of said top body portion, said element being supported on the top edge of said main body portion so as to form said small space.