centrifugation

1. CENTRIFUGATIO
N

2. CONTENTS
 Definition of centrifugation
 History
 Principle of centrifugation
 Classification
 Operation
 Construction
 Application in Pharmaceutical industry
 Advantages & disadvantages
 Safety measures
 importance
 Summary

3. WHAT IS CENTRIFUGATION?
Centrifugation is one of the most important and widely applied research
cellular techniques in bio-chemistry and molecular biology, pharmacy and in
medicine.
 Centrifugation is a process which involves the use of the
centrifugal force for the sedimentation of heterogeneous mixtures
with a centrifuge.
 A centrifuge is a device which consists of a container in which a
mixture of solid and liquid or two liquids is placed and rotated at
high speeds.
 Centrifugal force is an apparent force that acts outward on a body
moving around a center, arising from the body's inertia.

4. APPLICATIONS
 PRODUCTION OF BULK DRUGS: Separation of crystalline drugs such as
aspirin from mother liquor.
 PRODUCTION OF BIOLOGICAL PRODUCTS: Proteinaceous drugs and
macromolecules – colloidal dispersions in water – Insulin from other
fractions of proteins; blood cells from blood.
 Biopharmaceutical analysis of drugs: Drugs in Blood, tissue fluids and urine
– PK and BE studies.
 Evaluation of Suspensions and emulsions: Creaming – Stable emulsion – no
separation – Centrifuging at 2000 – 3000 rpm at RT.
 Determination of molecular weight: Polymer – serum albumin, insulin, MC
– ultracentrifuge.

5. THEORY OF CENTRIFUGATION
Particles having above 5 µm sediment due to gravitation force. Lessthan
5 µm particle undergo Brownian motion, they do not sediment under
gravity. Hence a stronger force (Centrifugal force) is applied to separate.
Consider a body of mass m kg rotating in a circular path or radius r mtrs at
a velocity v mtrs per minute. The force acting on the body in a radial
direction is given by :
F= mv2
/ r
Where,
F= Centrifugal force N m= effective mass of the sedimenting particle
v= angular velocity of rotation r= distance of the migrating particles from
the central axis of rotation
The same body is experiencing gravitational force, Gravitational Force G = mg
g = acceleration due to gravity

6. Centrifugal Effect = F / G = mv2
/ mgr = v2
/ gr
But v = 2 пrn; n = speed of rotation substituting
C = (2 пrn )2
/ gr = 4 п2
r2
n2
/ gr = 4 п2
r n2
Since 2r = d (dia of rotation)
C = 2 п2
d n2
/g
The gravitational constant has a value of 9.807 m/s2
Equation can be written as Centrifugal Effect = 2.013 n2
d
Centrifugal effect α diameter
Centrifugal effect α (speed of rotation) 2

7. CLASSIFICATION OF CENTRIFUGATION

8. CLASSIFICATION OF CENTRIFUGATION
BASED ON MECHANISM OF SEPARATION
SEDIMENTATION CENTRIFUGE
ULTRACENTRIFUGE
FILTRATION CENTRIFUGE
BASED ON SCALE OF USAGE
Laboratory scale : Horizontal spinning arm type
Angle Centrifuge (45 to 50 angle)
High speed centrifuge (10,000 rpm)
Ultracentrifuge (85,000 rpm) Commercial Scale
Batch Type: Perforated Basket Type
Semi-continuous Scale : Short-cycle batch centrifuge
Continuous Centrifuge : Supercentrifuge

9. SEDIMENTATION
CENTRIFUGEUtilizes density difference between the particles and the medium in which
these are dispersed and efficiency depends on velocity of rotation.
Ex :- Horizontal continuous centrifuge, super centrifuge, conical disc
centrifuge.
ULTRA-CENTRIFUGE
In colloidal research, very extremely fine solid material is to be separated.
In this a relatively small motor with speeds exceeding 1,00,000 rpm and
force 1 million times gravity.
Uses: To remove
•Dirt and water from olive & fish liver oils
•Bacteria in the preparation of bacterial enzymes
•Precipitated proteins in manufacture of insulin
Separation of
•Blood plasma from whole blood
•Antibiotics preparation
•Suspensions containing low conc. of solids
•Lanolin from wool

10. ULTRA-CENTRIFUGE
Advantages and Disadvantages:
•Compact , occupy small space
•Efficiency is very high
•Two immiscible liquids easily separated by continuous process
•By speed control, separated coarser, leaving finer in the suspension.
•Complicated construction
•Limited capacity
FILTRATIONCENTRIFUGE
Solid pass through porous membrane based on density differences. Filter
medium used are canvas or metal cloth. Ex: Perforated basket and semi
continuous centrifuge.
Uses:
•Solid recovery and To remove unwanted solids from liquids ex: insulin
Advantges and Disadvantages: Slurries with high proportions, even paste
•Final product – low moisture content
•Dissolved solids separation from the cake
•Entire cycle complicated – Labour cost is high
•Batch or semi continuous process
•Hard cake formation – removal of cake is difficult

11. 1. Perforated-basket centrifuges
(filtration centrifuge)

12. Basket – copper, monel or other suitable metal and covered
with vulcanite or lead, greatest resistance to corrosion.
Dia – 0.9m ; capacity – 0.085 m3.
Power – 5 kw for starting and 2 kw for running
Rpm – basket rotates at 1000rpm

13. Wear and tear, on prolonged operation – hard cake
formation
Cycle is complicated

14. NON-PERFORATED BASKET
-CENTRIFUGE(SEDIMENTATION CENTRIFUGE)
CONSTRUCTION:
•Basket – steel other suitable metal
•Suspended on vertical shaft
WORKING:
•Solid phase is retained on the sides, liquid remains on the top
•Liquid is removed by weir or skimming tube
•Solids are scraped off by hand or using a scraper blade.
USES:
•When deposited solids offer high resistance to the flow of liquid.

15. SHORT CYCLE AUTOMATIC BATCH
CENTRIFUGEPRINCIPLE: FILTRATION CENTRIFUGE
WORKING:
•Basket is allowed to rotate and slurry is introduced from the side pipe.
•During centrifugation, slurry passes through the perforated wall.
•Solids retained on the wall, liq collected at outlet.
•Cake is washed with water – washings escape through the filtrate outlet.
•Desired thickness(50-70mm), the feeler cuts off the air supply to a diaphragm
valve that shuts the feed entry.
•Hydraulic cylinder is actuated, lifts the knife along with discharge chute.
•Knife does not cuts the cake completely, leaves a layer to acts as filter medium
for further separation in next cycle.
•The discharge crystals contain 2 to 4 % moisture.
Advantages and Disadvantages:
•Solids drained fast from the bowl.
•Discharge, breakage of crystals
•More Moving parts – complicated construction

16. CONSTRUCTION:
•Vertical perforated basket supported by horizontal drive
•Provision for feed, wash pipe at center
•Feeler rides over the feed to control the thickness of the cake
•Hydraulic cylinder attachment for entry of discharge chute from the
sides of basket, when discharge of crystals required.

18. 3. Continuous centrifuge

19. CONTINUOUS HORIZONTAL CENTRIFUGE
PRINCIPLE: SEDIMENTATION CENTRIFUGE
CONSTRUCTION:
•Cylindrical or conical bowl mounted horizontally with dia 0.5m
•Within a bowl screw conveyor is attached – rotates same direction as bowl
but slightly slower speed
WORKING:
•Bowl and screw conveyor are allowed to rotate and slurry is introduced
through the shaft.
•During centrifugation, liq moves to wider portion and sedimentation of
particles takes place.
•Solids are lifted by the screw conveyor, while liq is continuously drained.
•Solids are conveyed to a dry beach where they get dried.
USES: High proportion of solids.
Advantages and Disadvantages:
•Flexible in operation.
•Capable of handling solids larger (10-15mm) or smaller (few microns)
•0.5 to 50% concentrate slurries -use

20. 1. Cylindroconical bowl
2. Helical extraction screw (scroll)
3. Feed
4. Distributor
5. Ring space
6. Settled product
7. Liquid level
8. Drying zone
9. Clarified liquid
10.Adjustable thresholds
CONTINUOUS HORIZONTAL CENTRIFUGE

21. SUPER CENTRIFUGE
PRINCIPLE: SEDIMENTATION CENTRIFUGE
CONSTRUCTION:
•Long hollow cylindrical bowl – small diameter
•Suspended from a flexible spindle at the top and guided by loose
fit bushing at bottom.
•Feed inlet using pressure – bottom
•Liquid outlets 2 at different heights – top
•Modified wiers are attached.
WORKING:
•Allowed to rotate on its longitudinal axis at higher speed
(2000rpm) with help of drive assembly.
•Feed is introduced at the bottom with pressure
•During centrifugation the heavier liq thrown outward (against
wall), lighter liq forms an inner layer. Both liq rise to top
•The liq –liq interface is maintained by an hydraulic balance.
•Thus, 2 layers are separated continuously by modified wiers
USE : Emulsions
Variant:
•Tubular bowl centrifuge – separation of solids and liquids

22. 2. Tubular-bowl centrifuges
(centrifugal sedimenters)

23. Fig: Tubular-bowl centrifuge

24. CONICAL DISC CENTRIFUGE or DE LAVAL CLARIFIER
(Sedimentation Centrifugation)
Clarifier, solids or immiscible liquids are present in low conc. A no. of cone
shaped plates are attached to a central shaft (Feed provisions). Dense solids
are thrown outwards – underside of the cone shaped casing, lighter
clarified liq passes over the bowl and recovered from the top of the cone
CONSTRUCTION:
•shallow bowl – series of conical discs – to
centre shaft at diff elevations
•Disc – thin sheet of metal or plastic separated
by narrow spaces.
WORKING:
•Allowed to rotate on its longitudinal axis at
low speed and short time
•During centrifugation the heavier liq thrown
outward (against wall), lighter liq forms an
inner layer. Both liq rise to top
•Substances moves along the surface of the
disc to the limit of inner and outer layers.
•Solids deposit at bottom of cone, removed
intermittently
• Matching holes in disc – channels to
pass the liq.
• A concentric tube is placed
surrounding the central drive shaft.
(Feed entry)

25. USES:
•Immiscible liq separation – Mfr of antibiotics
•Suspensions containing low solids
•Solids – gelatinous or slimy – separated
•Collection od starch
•Insulin
•Concentration of one fluid phase – separation of cream from milk
ADVANTAGES:
•Small space occupying
•Separation efficiency – high, particles are sediment very rapidly
•Suitable – fluid is deposit or sludge
•By controlling speed of rotation and rate of flow – particles are separated into two size
fractions.
DISADVANTAGES: Complicated construction , Limited capacity
•Not suitable for hard cake forming solids

26. Fabrication: Carbon fiber, Aluminum and
Titanium.

28. Some Other Commercial
applications
in water and wastewater treatment to dry sludge.
from the mother liquor .
 In soil mechanics.
 Large industrial centrifuges are commonly used
 In sugar industry to separate the sugar crystals
 Standalone centrifuges for drying (hand-washed)
clothes – usually with a water outlet.
 Large industrial centrifuges are also used in the
oil industry to remove solids from the drilling
fluid.
 Centrifuges are used in the attraction Mission

29. ADVANTAGES AND
DISADVANTAGES:
Advantages:
 Centrifuges have a clean appearance and have little to no odor
problems.
 Not only is the device easy to install and fast at starting up
and shutting down, but also only requires a small area for
operation.
 They can be selected for different applications. .
 The device is simple to operate .
 Centrifuge has more process flexibility and higher levels of
performance.

30. DISADVANTAGES:
 The machine can be very noisy and can
cause vibration.
 The device has a high-energy consumption
due to high G-forces.
 High initial capital costs

31. SAFETY MEASURES
A centrifuge user should strictly observe the following
precautions :
 Manufacturer’s manual should be strictly followed.
 Rotor should be stored in proper containers.
 Attention should be given to imbalance detectors.
 Rotor speed should not exceed the assigned speed.
 Lid of the rotor chamber should remain locked during
operation.
 To avoid the rotor failure, manufactures instructions
regarding rotor care and use should always be
followed.

32. SUMMARY
 The centrifugation is a modern & easy
technique of separation and sedimentation on
the basis of shape, size and density of
macromolecules and other particles.
 In the centrifugation there are different types
of forces are applied like as centrifugal force,
gravitational force and centripetal force etc.
and also different types of rotors are to be
used that is; Swinging Bucket Rotor and fixed
angle rotors at different RPM/RCF.

33. IMPORTANCE
Centrifugation play an important
role in both biological sectors as
well as industrial sectors.
In biological sector:
 Medical laboratories use
centrifuges to separate plasma
from heavier blood cells.
 Modern centrifuges can even
separate mixtures of different
sized molecules or microscopic
particles such as parts of cells.

34. Continued…..
In Industrial Sector:
 Cream separation from milk.
 Separating textiles
 Separating particles from an air flow using
cyclonic separation
 Clarification and stabilization of wine
 Centrifugation is the most common method
used for uranium enrichment.

35. REFERENCES
http://www.labmanager.com/lab-product/2010/05/evolution-of-the-lab-
centrifuge?fw1pk=2#.Viz08yskqxn
http://www.westernstates.com/continuous-centrifuges
https://en.wikipedia.org/wiki/Centrifuge
https://en.wikipedia.org/wiki/Differential_centrifugation
http://cellbiologyolm.stevegallik.org/node/74
 D. Rickwood and J. M. Graham (2001); Biological Centrifugation,
Springer Verlag; ISBN: 0387915761.
 D. Rickwood, T. Ford, J. Steensgaard (1994): John Wiley & Son Ltd.
ISBN: 0471942715.
 T. C. Ford and J. M. Graham (1991): An Introduction to Centrifugation,
BIOS Scientific Publishers, Ltd. ISBN 1 872748 40 6.
 http://www.thermoscientific.com/content/dam/tfs/LPG/LED/LED%20
Documents/Third-
Party%20Papers/Centrifuges/Centrifuge%20Rotors/Ultracentrifuge%20R
otors/D20940~.pdf