A semi-continuous centrifuge consists of a perforated basket mounted on a horizontal shaft that rotates continuously. Suspension is introduced through a feed pipe and passes through the perforated basket wall, with crystals remaining inside while filtrate exits. When the cake height reaches 2-3 inches, suspension input stops and the basket rotates to wash the cake with water. A hydraulic knife then cuts the cake from the basket to be collected. This type of centrifuge is used to separate crystals from mother liquor or clarify liquids by removing solids, though it has disadvantages of being complicated, potentially breaking crystals, and high power usage.

1. Semi Continuous
Centrifuge
MADE BY KASHISH WILSON
ASSISTANT PROFESSOR
MM COLLEGE OF PHARMACY MM(DU) MULLANA,AMBALA

2. Introduction...
 In Semi Continuous centrifuge, separation occurs through perforated wall
depends on the difference in the densities of solid and liquid phases.
Construction It consist of perforated basket mounted on horizontal shaft and
run continuously by motor.

3. Principle & Construction
 In Semi Continuous centrifuge, separation occurs through a perforated wall
depending on the difference in the densities of solid and liquid phases.
 Construction:-Semi Continuous Centrifuge consists of a perforated basket
mounted on a horizontal shaft and run continuously by the motor. The side of
the basket is perforated. Feed or suspension is introduced through a feed
pipe. There is also the provision of a wish pipe which is used to wash the
crystals. The thickness of the feed depends on the feeler which rides over the
feed. The layer of cake is removed by a chute fitted with a knife. The knife
cuts down the cake within the basket. The knife-chute assembly is raised with
the help of a hydraulic apparatus.

5. Working..
 The basket is rotated horizontally with a motor. The suspension is introduced
through the pipe. The slurry passes through the perforated side. The crystals
remain inside the basket. The filtrate is eliminated from the outlet. When the
height of the cake is approximately 2-3 inches, the suspension inlet is stopped
by a “feeler diaphragm valve assembly”. The basket rotates at a
predetermined time and then the cake is washed with water. The basket is
rotated for another predetermined time. After that, the hydraulic apparatus
raises the knife-chute assembly to cut the cake. The cake is collected through
the chute.

6. Advantages & Disadvantages
 Advantages
 This centrifuge is used to separate crystals from the mother liquor.
 This is used to clarify Liquids by removing unwanted solids and dirt from oils.
 Disadvantage
 Complicated process
 Sometimes chances of breakage of the crystal during discharge.
 High power consumption
 Make sure you also check

7. Thanks.....