Now, centrifuges are widely used, not only in mineral processing, coal and other industries, but also in cutting-edge industries such as medicine and aerospace. Therefore, although the centrifuge is small, its role is very large. It's also helpful to know how it works and how it works. The following small series will give you a detailed introduction, you must take a closer look.

What is a centrifuge?

Centrifuges use centrifugal force to separate each component of a liquid machine from solid particles or a mixture of liquid and liquid. Centrifuges are mainly used to separate solid particles from liquids in suspensions, or to separate two incompatible liquids of different densities in emulsions (for example, to separate cream from milk); It can also be used to remove liquids from wet solids, such as drying wet clothes in a washing machine; Special high-speed tube separators can also separate gas mixtures of different densities; Taking advantage of the fact that solid particles of different density or particle size in the liquid settle at different speeds, some sedimentation centrifuges can also classify solid particles according to density or particle size.

How a centrifuge works

When the suspension containing fine particles is standing, the suspended particles gradually sink under the action of gravity field. The heavier the particle, the faster it sinks, otherwise particles that are less dense than liquid will rise. The speed at which a particle moves in a gravitational field is related to the size, shape and density of the particle, as well as to the strength of the gravitational field and the viscosity of the liquid. Particles the size of red blood cells a few microns in diameter can be observed under normal gravity.

In addition, when the substance settles in the medium, it is accompanied by the phenomenon of diffusion. Diffusion is unconditional and absolute. Diffusion is inversely proportional to the mass of the substance, and the smaller the particle, the more serious the diffusion. Settlement is relative and conditional and can only be driven by external forces. The settlement is proportional to the weight of the object, and the larger the particle, the faster the settlement. For particles smaller than a few microns, such as viruses or proteins, which form a colloidal or semi-colloidal state in solution, the sedimentation process cannot be observed by gravity alone. Because the smaller the particles, the slower the settlement, the more serious the diffusion phenomenon. Therefore, it is necessary to use a centrifuge to generate a strong centrifugal force that forces these particles to overcome diffusion and produce sedimentation motion.

Centrifugation is to use the powerful centrifugal force generated by the high-speed rotation of the centrifugal rotor to accelerate the sedimentation rate of the particles in the liquid and separate the materials with different sedimentation coefficients and buoyancy densities in the sample.