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HYDRAULIC AND PNEUMATIC CLASSIFICATION
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Main parameter - velocity of settling of
particles
Fc Fo Fb 0
Fc - gravity force of particle in liquid Fo -
resistance force Fb - inertia force
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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
?
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or
4/3Ar ? Re2
because
?c - viscosity of liquid
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(No Transcript)
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spherical particles
Stokes range Re lt 0.2, from 0.01mm to 0.1mm
Allens range 0.2ltRe lt 5x102, from 0.1mm to
1mm
Newtons range 5x102 ltRe lt 3x105, above 1mm
??-particle density in water, ?-viscosity,
d-particle diameter, g-gravity constant, k - a
constant, ?c -liquid density
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Modes of hydraulic classication
- stationary - horizontal - vertical -
pulsation - spiral
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cone classifier
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elutriator
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pocket classifier
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plunger jig
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hydrocyclone