Patent ID: 7523831

Claim:
A method for classifying a mixture of splinters and wood chips comprising coarser and finer particles with different masses, wherein the mixture is dispensed at a centrifugal classifying unit and drops into a classifying chamber, in which the majority of the mixture is transported into a rotor of the centrifugal classifying unit by means of a countercurrent of gas or a gas mixture circulated with the aid of a blower, coarser particles are thrown back into the upper classifying chamber against the gas flow by the rotor and finer particles are entrained by the gas flow against the centrifugal effect of the rotor, transported to a separating cyclone and separated, the particles that were either ejected by the rotor or dropped past the rotor are delivered to a countercurrent classifier comprising a through-opening around a flow member arranged in an adjustable fashion, the through-opening having a free cross section increased by raising the flow member and decreased by lowering the flow member, and the content of fine particles that has passed by the centrifugal classifying unit is returned to the centrifugal classifying unit with the corresponding gas flow, and the coarse fraction is separated in a separating funnel at the end of the countercurrent classifier.