CENTRIFUGE WITH ADJUSTABLE SPEED AND DIRECTION OF ROTATION

BY: AARTI SHINDE JYOTI SHUKLA MANISH PILLAI SARANYA NAIR

INTRODUCTION

A centrifuge is a piece of equipment, generally driven by a motor, that puts an object in rotation around a fixed axis, applying force perpendicular to the axis.

PHYSIOLOGICAL BACKGROUND

Early instruments were hand powered, but in 1912, with the introduction of electric centrifuges, that changed. The early centrifuges were mostly used for non-biological applications, such as separating milk and collecting precipitates.

PRINCIPLES OF CENTRIFUGE

The centrifuge works using the sedimentation principle, where the centrifugal force is used to separate substances of greater and less density.

Basis of separation: Size Shape Density

CENTRIFUGAL FORCE

Let us consider a body of mass m rotating in a circular path of radius r at a velocity v. The force acting on the body in a radial direction is given by:

F =

The same body experiencing gravitational force. This can be expressed as, G = mg

CONTINUED...

The centrifugal effect is the ratio of the two forces, so that: C = F / G

= mv2 / mgr

= v2 / grBut v = 2πrn

So, F / G = (2πrn)2 / gr

= 4π2r2n2 / gr

= 2 π2n2d / g ------------------------ (1)

g = 9.807

Centrifugal effect = 2.013 n2d

Provided that n is expressed in s-1 and d is in meter.

METHODOLOGY

Suspension

In process

Induced gravitational field

Precipitate

Supernatant

Separation complete

Pellet

Supernatant

Relative centrifugal force or Centrifugal effect

TYPES OF ROTORS

Fixed Angle Rotor

Swinging Bucket Rotor

BLOCK DIAGRAM

MOTOR DRIVER

MOTOR

TEST TUBES

ATMEGA 8

KEYPADLCD

DISPLAY

POWER SUPPLY

ATmega8-Microcontroller

MEMBRANE KEYPAD

VOLTAGE REGULATOR

L293D

DC MOTOR

DC MOTOR

LCD

CRYSTAL

10 K RESISTOR

100 microfarad CAPACITOR

Bug strip Male

Bug strip Female

CIRCUIT DIAGRAM

Production of bulk drugs

Production of biological products

Biopharmaceutical analysis of drugs

Evaluation of suspension and emulsion

Blood plasma is separated from whole blood

Different particle size fractions are separated by using control of speed of rotation and rate of flow

APPLICATIONS OF CENTRIFUGE

ADVANTAGES

Faster and reliable

Several specimens can be centrifuged at ago e.g. blood &urine

Not tiresome as compared to manual centrifuge machine

Safe once the specimen are enclosed into the machine

 

DISADVANTAGES

Time wasting to the patient

Exhausting of the laboratory technician

Specimens may spill out of the test tubes

The capacity is limited.

CONCLUSION

Thus, we can see that the centrifuge machine is an essential medical device for every biological and clinical laboratory as well as medical practice.

The centrifuge may seem a rather common machine, but newer models have become more complex, as higher speeds have become necessary for certain processes and applications and as more precise controls are needed.

BIBLIOGRAPHY

Basic medical laboratory techniques - Page 69 by Barbara H. Estridge, Anna P. Reynolds,

Norma J. Walters

Fundamentals Of Bioanalytical Techniques And Instrumentation - Page 118

by Ghosal & Srivastava

Basic Clinical Laboratory Techniques - Page 85by Barbara H. Estridge, Anna P. Reynolds

Thank You…