CENTRIFUGATION Dr. Basavaraj K. Nanjwade M. Pharm., Ph. D Department of Pharmaceutics Faculty of Pharmacy Omer Al-Mukhtar University Tobruk, Libya. 1 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 2014/05/20

CONTENTS Theory of centrifugation Vertically mounted centrifuges Horizontally mounted centrifuges Continuous centrifuges Ultra centrifuges References 2 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 2014/05/20

Theory of centrifugation Protocols for centrifugation typically specify the amount of acceleration to be applied to the sample, rather than specifying a rotational speed such as revolutions per minute. This distinction is important because two rotors with different diameters running at the same rotational speed will subject samples to different accelerations. During circular motion the acceleration is the product of the radius and the square of the angular velocity, and the acceleration relative to "g" is traditionally named "relative centrifugal force" (RCF). 3 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 2014/05/20

Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 4 Vertically mounted centrifuges

The suspension to be separated is filled into the vertically mounted perforated basket at pre-selected loading speed. Under the effect of the centrifugal force, the solid particles settle on the filter fabric on the basket shell. The solids are retained by the filter fabric, suspension fluid flows through the forming filter cake including the filter fabric and leaves the perforated basket through bore-holes in the basket sleeve. 5 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 2014/05/20

Horizontally mounted centrifuges 6 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 2014/05/20

The rotating assembly is mounted horizontally with bearings on each end to a rigid frame, which provides a good sealing surface for high-pressure applications. The horizontal machine is arranged in a way that slurry can be introduced at the centre of a rotating horizontal cylindrical bowl. The scroll discharge screw forces the solids to one end of the bowl as it is collected on the walls. This orientation is the most common design implemented in industry. 2014/05/20 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 7 Horizontally mounted centrifuges

Continuous centrifuges 8 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 2014/05/20

The Centrifuge is designed for applications where a continuous process or very high capacity is required. Continuous operations are best suited for applications that require high capacity and large (greater than 300 micron) particle size. These centrifuges can provide excellent washing and low final moisture. 2014/05/20 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 9 Continuous centrifuges

The ultracentrifuge is a centrifuge optimized for spinning a rotor at very high speeds, capable of generating acceleration as high as. There are two kinds of ultracentrifuges, the preparative and the analytical ultracentrifuge. Both classes of instruments find important uses in molecular biology, biochemistry, and polymer science. 2014/05/20 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 10 Ultra centrifuges

2014/05/20 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 11 Ultra centrifuges

THANK YOU /05/20 Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya. 12