Objectives, principle, application of centrifugation, perforated basket centrifuge, non-perforated basket centrifuge, semi-continuous centrifuge, super centrifuge

1. Centrifugation
Parag Jain
Assistant Professor
Chhattrapati Shivaji Institute
of Pharmacy
Durg, Chhattisgarh
Presented by

2. Definition
• Centrifugation is a process used to separate or
concentrate materials suspended in a liquid medium.
The theoretical basis of this technique is the effect of
gravity on particles (including macromolecules) in
suspension. Two particles of different masses will settle
in a tube at different rates in response to gravity.

3. Introduction
• Centrifugation is a process which involves the use of the
centrifugal force for the sedimentation of heterogeneous
mixtures with a centrifuge, used in industry and in
laboratory settings.
• This process is used to separate two immiscible liquids.
• More-dense components of the mixture migrate away from
the axis of the centrifuge, while less-dense components of
the mixture migrate towards the axis.

4. Principle
• A centrifuge is a device for separating particles from a
solution according to their size, shape, density,
viscosity of the medium and rotor speed.
• In a solution, particles whose density is higher than
that of the solvent sink (sediment), and particles that
are lighter than it float to the top.
• The greater the difference in density, the faster they
move. If there is no difference in density (isopyknic
conditions), the particles stay steady.

5. To take advantage of even tiny differences in density
to separate various particles in a solution, gravity can
be replaced with the much more powerful
“centrifugal force” provided by a centrifuge.

6. Centrifugation
Separation of
solid
substances
from highly
concentrated
suspensions
Separation of
Heavy
particles and
large sized
grains by
cycloning
Separation
of Oily
concentrated
sludge
Separation
of oily
suspensions
with low SS
contents

7. Other applications
• Separating chalk powder from water
• Removing fat from milk to produce skimmed milk
• Separating textiles
• Removing water from lettuce after washing it in a salad spinner
• Separating particles from an air-flow using cyclonic separation
• The clarification and stabilization of wine
• Separation of water particles from clothes while spin-drying in
washing machines
• Separation of urine components and blood components in
forensic and research laboratory

8. Centrifuge
• A centrifuge is a piece of equipment that puts an object
in rotation around a fixed axis (spins it in a circle),
applying a potentially strong force perpendicular to the
axis of spin (outward).
• The centrifuge works using the sedimentation principle,
where the centripetal acceleration causes denser
substances and particles to move outward in the radial
direction.
• At the same time, objects that are less dense are
displaced and move to the center. In a laboratory
centrifuge that uses sample tubes, the radial acceleration
causes denser particles to settle to the bottom of the
tube, while low- density substances rise to the top.

9. PERFORATED BASKET
CENTRIFUGE
•Basket centrifuges are often called centrifugal filters or
clarifiers. They have a perforated wall and cylindrical
tubular rotor.
•The basket centrifuge is employed in the manufacture of
cane sugar, in the home and in laundries for the rapid
drying of clothes, and in the washing and drying of
many kinds of crystals and fibrous materials, etc.

10. PERFORATED BASKET CENTRIFUGE
• Two types:-
✓Under driven
✓Over driven
• Under driven PBC:-
In this centrifuge a basket is mounted above a
driving shaft. Such arrangement is described as
under driven

11. PERFORATED BASKET CENTRIFUGE
• Over driven PBC:-
If the basket is suspended from a shaft .it is
described as over driven

12. PERFORATED BASKET CENTRIFUGE
UNDER DRIVEN PERFORATED BASKET
CENTRIFUGE
Principle:-
• It is a filtration centrifuge
• The basket contains a perforated side wall
• The separation based on the difference in
densities of solid and liquid phases

13. PERFORATED BASKET CENTRIFUGE
• During centrifugation, the liquid phase passes
through the perforated wall, while solid phase
is retained in the bowl
• The solid is removed by using a blade

14. PERFORATED BASKET CENTRIFUGE

15. PERFORATED BASKET CENTRIFUGE
Construction:-
• It consists of a basket, made of steel,(some times
covered with vulcanite or lead) or copper or
monel (it should be corrosion resistant material)
• The basket may have
0.90 metre diameter
0.085 metre cube capacity

16. PERFORATED BASKET CENTRIFUGE
• The basket may require
❖ 5 kilowatt power for starting
❖ 2 kilowatt power for running
A casing provided to collect the filtrate and
discharges it at the outlet

17. PERFORATED BASKET CENTRIFUGE
Working
• The material placed in the basket when the
basket is stationary
• The amount of materials placed should be
optimum otherwise the load will induce great
strain on the basket

18. PERFORATED BASKET CENTRIFUGE
• Power applied to rotate the basket
• The basket runs at 1000 RPM
• The power required for running is small
compared to the power required for starting
and bringing it to the full speed

19. PERFORATED BASKET CENTRIFUGE
• During centrifugation, the liquid passes
through the perforated wall, while solid phase
retains in the basket
• Liquid leaves the basket and is collected at the
outlet

20. PERFORATED BASKET CENTRIFUGE
• The cake is spun to dry as much as possible
• After a definite period of time the power is
turned off
• The basket is brought to rest
• The solid cake is cut using a blade and then
unloaded manually

21. PERFORATED BASKET CENTRIFUGE
Uses:-
Used for separating crystalline drugs from mother
liquor
e.g., aspirin
If mother liquor completely removed, free flowing
products obtained

22. PERFORATED BASKET CENTRIFUGE
Used to remove unwanted solids from a liquid
e.g., precipitated proteins are removed from
insulin
Sugar crystals are separated using perforated
basket centrifuge

23. PERFORATED BASKET CENTRIFUGE
Advantages:-
• Centrifuge is very compact and it occupies
very little floor space
• Slurries containing high proportion of solids
can be handled
• Materials having paste like consistency can
also separated

24. PERFORATED BASKET CENTRIFUGE
• The final products contain low moisture
content
• The process is rapid
• The cake containing dissolved solids can be
separated

25. PERFORATED BASKET CENTRIFUGE
Disadvantages :-
• The entire cycle is complicated resulting in
considerable labour costs
• Batch process
• Wear and tear of the equipment
• Solids may form hard cake, difficult to remove

26. NON-PERFORATED
BASKET CENTRIFUGE

27. NON-PERFORATED BASKET
CENTRIFUGE
Principle:-
❖It is an example for sedimentation centrifuge
❖The separation is based on the difference in
densities of solid and liquid phases without a
porous barrier

28. NON-PERFORATED BASKET
CENTRIFUGE
❖The NPBC contains a non perforated side wall
❖During centrifugation solid phase is retained
on the sides of the basket while the liquid
remains at the top
❖This liquid is removed with the help of a
skimming tube

29. NON-PERFORATED BASKET
CENTRIFUGE

30. NON-PERFORATED BASKET
CENTRIFUGE
Construction:-
❖ Under driven non perforated basket centrifuge
consists of a basket
❖ The basket may be made of steel or any other
suitable material
❖ The basket is suspended on a vertical shaft and is
driven by motor using suitable power system

31. NON-PERFORATED BASKET
CENTRIFUGEWorking:-
The suspension fed continuously in to
the basket .During centrifugation solid
phase is retained on the sides of the
basket, while liquid remains on the top
The liquid is removed using a skimming tube
When suitable depth of solids deposited the
operation is stopped
Solids are then scraped off by hand or using a
scraper blade

32. NON-PERFORATED BASKET
CENTRIFUGE
Uses:-
When the deposited solids offer greater resistance
to the flow of liquid. In such cases non perforated
basket centrifuge is used

33. SEMI CONTINUOUS CENTRIFUGE

34. SEMI CONTINUOUS CENTRIFUGE
SHORT CYCLE AUTOMATIC BATCH CENTRIFUGE
Principle:-
❖Filtration centrifuge
❖The bowl contains a perforated side wall
❖The separation is through a perforated wall
based on the difference in densities of solid
and liquid phases

35. SEMI CONTINUOUS CENTRIFUGE
❖During centrifugation, the liquid phase passes
through the perforated wall, while solid phase
retains in the bowl
❖The solid is washed and removed by cutting
the sediment using a blade

37. SEMI CONTINUOUS CENTRIFUGE
Construction:-
❖It consists of a vertical perforated basket
❖The basket is supported from a horizontal
shaft driven by a motor
❖Slurry inlet and wash water pipes are
introduced from the side of the basket

38. SEMI CONTINUOUS CENTRIFUGE
❖The thickness of the feed depends on the
feeler which rides over the feed
❖The layer of the cake is removed by a chute
fitted with knife

39. SEMI CONTINUOUS CENTRIFUGE
❖The knife cuts down the cake within the basket
❖The knife-chute assembly is raised with the
help of a hydraulic apparatus

40. SEMI CONTINUOUS CENTRIFUGE
Working:-
❖The basket is rotated horizontally with a motor
❖The slurry is introduced through the pipe
❖During centrifugation slurry passes through
the perforated wall

41. SEMI CONTINUOUS CENTRIFUGE
❖The solids retained in the basket while filtrate
leaves the basket
❖Filtrate collected at outlet
❖The cake is washed with water. The washed
water escape from the basket through the
filtrate outlet

42. SEMI CONTINUOUS CENTRIFUGE
❖After achieving the desired thickness of the
cake the slurry inlet is stopped by a feeler-
diaphragm –valve assembly
❖The basket rotates predetermined time and
then the cake is washed with water again
rotated for another predetermined time

43. SEMI CONTINUOUS CENTRIFUGE
❖The hydraulic cylinder is actuated which lifts
the knife along with the discharge chute
❖The knife does not cut the cake completely but
leaves a layer of crystals that act as a filter
medium for further separation in the next cycle
❖The cake is collected through the chute

44. SEMI CONTINUOUS CENTRIFUGE
Advantage:-
❖Solids can be drained fast from the bowl
Disadvantages:-
❖Moving parts involved so construction and
functioning is complicated
❖During discharge breakage of cake occurs

45. SUPERCENTRIFUGE

46. SUPERCENTRIFUGE
❖Continuous centrifuge used for separating two
immiscible liquids

47. SUPERCENTRIFUGE
Principle:-
❖Sedimentation centrifuge
❖Separation is based on the difference in
densities between two immiscible liquids

48. SUPERCENTRIFUGE
❖During centrifugation the heavier liquid is
thrown against the wall while the lighter liquid
remains as an inner layer
❖This two layers are simultaneously separated
using modified weirs

50. SUPERCENTRIFUGE
Construction:-
❖It consists of a long hollow cylindrical bowl of
small diameter
❖The bowl is suspended from a flexible spindle
at the top and guided at the bottom by loose fit
bushing
❖It is rotated on its longitudinal axis

51. SUPERCENTRIFUGE
❖Feed is introduced through the bottom through
a nozzle with pressure
❖Two liquid outlets provided at different heights
at the top of the bowl

52. SUPERCENTRIFUGE
Working:-
❖The centrifuge rotate on its longitudinal axis at
approximately 2000 RPM
❖The feed introduced from the bottom using a
pressure system

53. SUPERCENTRIFUGE
❖During centrifugation two liquid phases
separate based on the difference in their
densities
❖The heavier liquid is thrown against the wall,
while the lighter liquid forms an inner layer

54. SUPERCENTRIFUGE
❖Both the liquid rise to the top of the vertical
bowl
❖The liquid-liquid interface is maintained by an
hydraulic balance
❖This two liquids removed from different
heights through modified weirs

55. SUPERCENTRIFUGE
Uses:-
❖Separation of emulsions in food and
pharmaceuticals

56. Website: www.probecell.com Email: probecellinfo@gmail.com
Ph: 7415211131
Office: Smriti Nagar, Bhilai, Chhattisgarh - 490020
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