Second hand centrifuge model priceWhen a suspension containing fine particles is stationary, the suspended particles gradually sink due to the effect of the gravity field. The heavier the particle, the faster it sinks, while particles with a lower density than liquids will float up. The speed at which particles move in a gravitational field is related to their size, shape, and density, as well as the strength of the gravitational field and the viscosity of the liquid. Particles the size of red blood cells, with a diameter of several micrometers, can be observed to settle under normal gravity.

In addition, diffusion phenomena also occur when substances settle in a medium. Diffusion is unconditional and absolute. Diffusion is inversely proportional to the mass of matter, with smaller particles causing more severe diffusion. And settlement is relative and conditional, requiring external forces to move. Settlement is directly proportional to the weight of the object, with larger particles settling faster. For particles smaller than a few micrometers, such as viruses or proteins, they form in solutionIt is impossible to observe the settling process using gravity alone in a colloidal or semi colloidal state. Because the smaller the particles, the slower the settling, and the more severe the diffusion phenomenon. So it is necessary to use a centrifuge to generate strong centrifugal force in order to force these particles to overcome diffusion and produce settling motion.

Centrifugation is the use of the strong centrifugal force generated by the high-speed rotation of the centrifuge rotor to accelerate the settling velocity of particles in the liquid, separating substances with different settling coefficients and buoyancy densities in the sample.