HYDRAULIC AND PNEUMATIC CLASSIFICATION

Main parameter - velocity of settling of particles Fc + Fo + Fb = 0 Fc - gravity force of particle in liquid Fo - resistance force Fb - inertia force

Fc = Vd  g Fo = 0,5  c v2 A Fb = Vd (d + ad c) dv/dt A – area of projection of the maximum cross section of the falling object perpendicularly to its movement, m2 Vd – particle volume, m3 ad – acceleration coefficient (dimensionless) (0,5 for spheres, 0.75 for discs) t – time, s g – acceleration due to gravity, m/s2 -friction coefficient d - particle diameter - particle density in medium c - medium density d - particle density v - velocity of settling Terminal settling velocity 

or 4/3Ar =  Re2 because c - viscosity of liquid

spherical particles Stokes range: Re < 0.2, from ~ 0.01mm to ~0.1mm Allen’s range: 0.2<Re < 5x102, from ~0.1mm to ~1mm Newton’s range: 5x102 <Re < 3x105, above ~1mm -particle density in water, -viscosity, d-particle diameter, g-gravity constant, k - a constant, c -liquid density

Modes of hydraulic classication: - stationary - horizontal - vertical - pulsation - spiral

cone classifier

elutriator

pocket classifier

plunger jig

hydrocyclone