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Separator working principle
Dec 15, 2017

When the suspension containing fine particles is stationary, the suspended particles gradually sink because of the action of the gravitational field. The heavier the particles, the faster the sinking, and conversely, the smaller particles that are smaller than the liquid will float up. The velocity of the particles moving in the gravitational field depends on the size, shape and density of the particles, and is related to the strength of the gravitational field and the viscosity of the liquid. The particle size of the red blood cell, which is a few microns in diameter, can be observed under normal gravity.

In addition, the diffusion phenomenon is accompanied by the settlement of the material in the medium. Diffusion is unconditional absolute. The diffusion is inversely proportional to the mass of the matter, and the smaller the particle is, the more serious the diffusion is. And the settlement is relative and conditional and can be moved by external force. The settlement is directly proportional to the weight of the body, and the larger the particles, the faster the settlement. For particles less than a few microns, such as viruses or proteins, they become colloidal or semi colloidal state in solution. Gravity is impossible to observe the settlement process. Because the smaller the particle is, the slower the settlement, and the more serious the diffusion phenomenon. So it is necessary to use the centrifuge to produce strong centrifugal force to force the particles to overcome the diffusion and produce the settlement movement.

Separation is the use of the strong centrifugal force produced by the high-speed rotation of the separator rotor to speed up the settling velocity of particles in the liquid, and separate the substances with different sedimentation coefficient and buoyancy density in the sample.