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Centrifugal principle of horizontal scraper centrifuge

Time: 2019-11-22 10:42:40 Source: Chongqing Jiangbei Machinery Co., Ltd.

Centrifugal principle of **horizontal scraper centrifuge**

When the suspension containing fine particles stands still, the suspended particles gradually sink due to the effect of the gravity field. The heavier the particles, the faster they sink, whereas the particles with a density lower than the liquid will float up. The speed at which particles move under the gravity field is related to the size, shape and density of the particles, and also to the strength of the gravity field and the viscosity of the liquid. Particles the size of red blood cells, several micrometers in diameter, can be observed to settle under normal gravity.

In addition, when the substance settles in the medium, it is accompanied by a diffusion phenomenon. Diffusion is unconditional absolute. Diffusion is inversely proportional to the mass of the substance, and the smaller the particles, the more severe the diffusion. The settlement is relative and conditional. It can only be moved by external force. The sedimentation is directly proportional to the weight of the object. The larger the particles, the faster the sedimentation. For particles smaller than a few microns, such as viruses or proteins, they are in a colloidal or semi-colloidal state in solution, and it is impossible to observe the sedimentation process using only gravity. Because the smaller the particles, the slower the sedimentation, and the more serious the diffusion phenomenon. Therefore, a strong centrifugal force needs to be generated by the centrifuge to force these particles to overcome the diffusion and settling movement.Centrifugation is to use the strong centrifugal force generated by the high-speed rotation of the centrifuge rotor to accelerate the sedimentation speed of particles in the liquid and separate the substances with different sedimentation coefficients and buoyancy densities in the sample.

Conversion between centrifugal force (g) and speed (rpm)

The conversion formula between centrifugal force G and RPM is as follows:

G = 1.11 × 10 ^ (-5) × R × (rpm) ^ 2

Among them, G is the centrifugal force, which is generally expressed in multiples of g (gravitational acceleration).

10 ^ (-5) is the negative fifth power of 10, (rpm) ^ 2 the square of the speed, R is the radius, and the unit is centimeter.

For example, a centrifugal radius of 10 cm and a rotation speed of 8000 RPM, the centrifugal force is:

G = 1.11 * 10 （－5） * 10 * （8000） 2 = 7104

That is, the centrifugal force is 7104g.

When the centrifugal force is 8000g, the speed should be: 8489, which is about 8500rpm.

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**Chongqing Jiangbei Machinery Co., Ltd.**

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Postcode: 401133

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