How a laboratory centrifuge works

A centrifuge is a machine that uses centrifugal force to separate components from liquid and solid particles or a mixture of liquid and liquid. Centrifuges are mainly used to separate solid particles from liquids in suspension, or to separate two immiscible liquids of different densities in emulsions (such as separating cream from milk); it can also be used to remove Liquids in wet solids, such as drying wet clothes with a washing machine; special ultra-speed tube separators can also separate gas mixtures of different densities; using the characteristics of different densities or particle sizes of solid particles in liquids, some sedimentation speeds are different. Centrifuges can also classify solid particles by density or particle size.      Due to the different densities and sedimentation coefficients of the sample components, the sample sediment after centrifugation will form a layered structure. The centrifugation process can be accomplished simply by decanting the supernatant. Centrifugal equipment laboratory centrifuge at 8000 rpm. The ultracentrifugation that has appeared in recent years is more than 10,000 revolutions per minute, and they are widely used in biochemistry, medical research (medical centrifuge), laboratory research (laboratory centrifuge), laboratory research (laboratory centrifuge), Blood separation tests (blood centrifuges) that separate red and white blood cells from plasma.      During the high-speed rotation of the centrifuge, the movement caused by the centrifugal force causes the solid matter suspended in the liquid to form sediment, that is, the object with a larger mass or volume in the suspension liquid moves in the direction of the larger radius of the rotor, while the mass or volume is larger. The smaller volume is deposited closer to the radius of the rotor. During centrifugation, the emulsion or suspension sample is placed in a thick-walled centrifuge tube, which is placed on the centrifuge rotor. It is characterized in that the centrifugal force generated by the rapid rotation of the centrifuge tube is driven by the rotor, and the components with higher density in the sample will accelerate to settle to the bottom of the centrifuge tube.      The centrifuge tubes are placed in pairs, and the capacity does not exceed about half. This prevents imbalance formation and sample spillage.Above we mentioned the concept of centrifugal force. A centrifuge is a machine that generates centrifugal force. The centrifugal force is related to the rotor radius, rotation speed and sample quality: that is, F=Rmω2 (F: centrifugal force: R: radius: m: sample quality: to: rotation speed), centrifugal force is an important measure of centrifuge One of the parameters is also one of the distinguishing criteria of the centrifuge grade. The centrifuge will give the high centrifugal force of the centrifuge when it leaves the factory.      We all know that the radius of the rotor and the quality of the sample are unchanged during operation, and only the rotational speed can be changed through control, so we are often used to describing a centrifuge by rotational speed. Such as: high-speed centrifuge, ultra-high-speed centrifuge, low-speed centrifuge.