METHOD FOR CLASSIFYING SUSPENDED PARTICLES

PURPOSE:To quantitatively classify suspended particles based on the size concerning the settling velocity by adjusting the flow rate of a suspension overflowing from a rotary settling tank and the revolving speed of the tank according to a specified equation and settling the suspended particles with the settling velocity exceeding a specified value into the tank. CONSTITUTION:A suspension to be treated is continuously supplied to the rotary settling tank 10 of a centrifuge, and the suspension overflowing from an overflow trough 12 of the tank 10 is returned to a settling tank 3 through a duct 13. The flow rate Q of the suspension overflowing the tank and the number of revolutions (n) are adjusted according to the equation, where D is the Stokes diameter (mum) of the particle, (k) is a constant, (r) is the inner radius (m) of the widest part of the tank, Q is flow rate (m /H) of suspension overflowing the tank, (n) is the number of revolutions (r.p.m.) of the tank. The suspended particle with the settling velocity exceeding that of the particles having the diameter larger than the Stokes diameter D is settled in the tank 10. As a result, the classification-point particle size concerning the settling velocity of the particle is quantitatively designed based on the Stokes diameter.