US 4,153,541 AGranted

Method and apparatus for the continuous centrifugal classifying of a continuous flow of particulate material in a deflected flow

OwnerHans Rumpf, Karl Maly +1inventors

InventorsHans Rumpf, Karl Maly, Kurt Leschonski

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Abstract

A continuous flow of material is separated in a continuous centrifugal classifying method into at least one fraction of coarse material and at least one fraction of fine material using a deflected flow with the stream of material introduced in a thin layer into a classifying flow which is deflected in a classifying region, the classifying flow being internally adjacent a curved inner deflection wall having an inner deflection angle greater than approximately 45.degree. and, the classifying flow also extending externally along a smaller outer deflection angle which is not defined by a wall but along which an outer flow for discharging the fraction of coarse material is established flowing substantially parallel to the inner deflection wall with the ratio between the radii of the outer and inner curvature being less than approximately 5 to 1, with the material to be classified introduced in the neighborhood of the beginning of the curvature of the inner deflection wall with a speed component in the direction of classifying flow which is at least half the speed of the classifying flow and which is in a direction which does not deviate by more than 45.degree. from the direction of the classifying flow with the fine material being primarily discharged with the outflowing classifying flow after being fanned out and the coarse material discharged with the external flow.

Claims37

Dependent claims

A method of continuous centrifugal classifying of a continuous stream of particulate material into at least one fraction of coarse material and at least one fraction of fine material in a deflected flow, the material to be classified being classified in a gaseous fluid at cut-off sizes between approximately 1 .mu.m and 100 .mu.m and a mass flow ratio up to 10, between the supplied stream of material and a classifying gas flow, and being classified in a liquid fluid at cut-off sizes between approximately 10 .mu.m and 1 .mu.m, comprising:

(a) providing a curved inner deflection wall curved from a beginning over an inner deflection angle greater than 45.degree.;
(b) establishing a classifying fluid flow which is deflected in a classifying region by said curved inner deflection wall and has, as an inner boundary, said curved inner deflection wall and has a curved outer boundary which is not covered by a wall over an outer angle smaller than said inner deflection angle, the classifying flow being substantially parallel to said inner deflection wall and abutting said inner deflection wall at least over said inner deflection angle;
(c) establishing an outer flow for carrying away the fraction of coarse material, the outer flow establishing the outer boundary of said classifying flow over said outer angle the ratio of radii between said outer boundary and inner deflection wall of said classifying flow being less than approximately 5:1;
(d) introducing a stream of material to be separated into the classifying flow in a thin layer in the vicinity of the beginning of curvature of the inner deflection wall in a direction such that the vector component of its velocity in the direction of the classifying flow is at least half the value of the velocity of the classifying flow and in a direction which does not deviate more than 45.degree. from the direction of the classifying flow, whereby fine material, after being fanned out by centrifugal force is discharged primarily with the out-flowing classifying flow, and the coarse material passes through said outer boundary of the classifying flow which is not covered and is discharged primarily with the outer flow.

1 more element

Apparatus for continuous centrifugal classification of a continuous stream of particulate material into at least one fraction of coarse material and at least one fraction of fine material in a deflected flow, the material to be separated being in a gaseous fluid for cut-off sizes between approximately 1 .mu.m and 100 .mu.m and a mass flow ratio of the supplied material to a classifying gas flow of up to approximately 10 and in a liquid fluid for cut-off sizes between approximately 10 .mu.m and 1 mm comprising:

(a) a flow channel for conveying a classifying flow which is continuously curved inwardly with a deflection angle of greater than 45.degree. to form a classifying region, the flow channel defined on its inside by a curved inner deflection wall having a curvature which begins near the entry point of the classifying flow into the classifying region and on its outside by a curved outer wall;
(b) a material supply device opening into one side of said channel at a material introduction point in the region of the beginning of the curvature of the inner deflection wall said supply device arranged to supply a stream of material to be classified in a thin layer in a direction deviating by not more than 45.degree. from the classifying flow at that point;
(c) a coarse material discharge aperture in said outer wall for discharging coarse material from the classifying region opposite the material introduction point, said coarse material discharge aperture having an upstream and a downstream edge defined by said outer channel wall of said flow channel, the discharge aperture being an opening in said outer channel wall and forming a continuation thereof and the discharge aperture extending over an outer deflection angle, the ratio between the radii of the outer and inner walls of the flow channel being less than 5:1,
(d) a coarse material discharge device adjacent said coarse material outlet aperture outside the flow channel;
and,
(e) a supply channel for a material free fluid opening opposite the material introduction point at the beginning of the coarse material discharge aperture such that the fluid emerges from said supply channel substantially parallel to the classifying flow, said material free fluid being used to discharge the fraction of coarse material.

3 more elements

Dependencies are inferred from the claim text.