Size separation uses mechanical sieving equipment to sort particles solely based on size. It can classify both dry and wet powders into narrowly sized fractions. There are three main mechanisms - agitation, brushing, and centrifugal force. Agitation involves oscillating, vibrating, or gyrating the sieve to give particles a spinning motion to pass through. Brushing uses a rotating brush to move particles along the sieve surface. Centrifugal force suspends particles in air and uses tangentially introduced high velocity air flow to generate rotary movement, separating particles based on size and density.

1. TOPIC
MECHANISM OF SIZE
SEPARATION
MAKE BY KASHISH WILSON
MM COLLEGE OF PHARMACY,MM(DU) MULLANA

2. : MECHANISM :
• Size separation is useful since particles are sorted into
categories solely on the basis of size, independently of other
properties such as density, surface, etc.
• It can be used to classify dry or wet powders and generates
narrowly classified fractions.
• While doing this mechanical sieving equipments used works on
the principle of agitation, brushing, and centrifugal force.

4. • AGITATION
• This gives a rotary movement of small amplitude to sieve which
turn gives spinning motion to the particles that helps to pass
them through a sieve.
• Agitation methods are not continuous methods’ but can be
made so by inclination of the sieve and the provision of
separate outlets for undersize and oversize particles.

5. AGITATION METHOD
• (i) Oscillation: In this case, the sieve is mounted in an inclined
frame or rack that oscillates back and forth. ...
• (ii) Vibration: Sieves in this mechanism vibrate at a high speed
mechanically or electrically, allowing powder material to pass
through. ...
• (iii) Gyration:

6. • BRUSHING METHOD
Brushing method – In this case, the particles are moved on the
surface of the sieve with the help of a brush. Normally, a circular
sieve rotates its brush in the middle, while a horizontal
cylindrical sieve rotates its brush along its longitudinal axis.

7. • CENTRIFUGAL METHOD
• Principle: centrifugal force is used to separate solid from
fluidised in air. (Separation depends on particle size & Density).
Solids are suspended in air and Force air introduced
tangentially at Higher velocity so that Rotary movement take
place.