Device and method for separating a flowing medium mixture into fractions
A device for separating a flowing medium mixture into at least two fractions, comprising rotating means ( 7 ) in the form of a rotating assembly of feed channels ( 6 ) for rotating the flowing mixture for separating, a feed for the medium mixture ( 5 ) for separating connecting to the rotating means, and an outlet connecting to the rotating means for discharging one of the fractions of the separated medium mixture, wherein the medium mixture can display a substantially turbulent flow during separation. Also disclosed is a method for separating a flowing medium mixture.
1. A method for separating a flowing medium mixture into at least two fractions with differing mass density, the method comprising:
a) supplying a flowing medium mixture for separating;
b) causing rotation of the flowing medium mixture in rotation means, said rotation means having a rotating assembly of feed channels, wherein the flow of the flowing medium mixture in the feed channels is substantially turbulent causing the flowing medium mixture to be separated into separate fractions; and
c) discharging at least one of the separated fractions,
wherein the rotational speed of the assembly of feed channels in which the flowing medium mixture is fed satisfies the condition
Ω.τ≦α.( L/d h ),
wherein Ω is the rotational speed, τ represents the treatment time in the feed channel, L and d h represent respectively the length and the hydraulic diameter of the feed channel, and α is smaller than 2.
2. The method of claim 1 , wherein the Reynolds number of the flow in the feed channels is greater than 2500 during processing step b).
3. The method of claim 2 , wherein the Reynolds number of the flow in the feed channels is greater than 5000 during processing step b).
4. The method of claim 1 , wherein at least one of the fractions comprises particles, the average diameter d of which satisfies d≧2 d p100% , wherein d p100% represents the diameter of a particle which in laminar flow reaches the wall of the feed channel at the downstream end of the feed channel under the influence of the occurring centrifugal forces.
5. The method of claim 4 , wherein at least one of the fractions comprises particles, the diameter d of which satisfies d≧2.5 d p100% .
6. The method of claim 1 , wherein α is smaller than 1.
7. The method of claim 6 , wherein α is between 0.5 and 1.