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Vibration excitation of a refrigerated centrifuge system

2019/4/9 14:11:58      click :

  The vibration excitation of the refrigerated centrifuge system is the motor drive system, the screen basket and machining error, the bearing and the bracket, the assembled unbalanced shaft, the crack rupture chamber water is formed outside the body, the problem caused by the overheated fault, the high centrifugal severity, the high speed Tilting the shaft, vibrating, when the vibration frequency exceeds the limit, will cause the centrifuge of the entire system to resonate, causing serious consequences.
  Due to the centrifugal force, refrigerated centrifuge leaves the original sample layer and settles to the bottom of the tube at different settling speeds. After centrifugation for a certain period of time, the settled particles are gradually separated, and finally a series of discontinuous zones with clear interfaces are formed. The larger the sedimentation coefficient is. The faster the sedimentation is, the lower the zone is presented. The centrifugation must be completed before the large sedimentation of the large particles reaches the bottom of the tube. The density of the sample particles is greater than the density of the gradient medium. Gradient media typically use a sucrose solution with a maximum density and concentration of 1.28 kg/cm3 and 60%. When the refrigerated centrifuge contains a suspension of fine particles, the suspended particles gradually sink due to the action of the gravitational field. The heavier the particles, the faster the sinking, whereas the particles with a lower density than the liquid will float. The rate at which particles move under the gravitational field is related to the size, morphology, and density of the particles, and is related to the strength of the gravitational field and the viscosity of the liquid. Particles of the size of red blood cells, a few micrometers in diameter, can be observed under normal gravity.
  In addition,refrigerated centrifuge material is accompanied by a diffusion phenomenon when it settles in the medium. Diffusion is unconditional and absolute. The diffusion is inversely proportional to the mass of the material, and the smaller the particle, the more severe the diffusion. The settlement is relative, and if it is conditional, it must be subjected to external forces to move. The settlement is proportional to the weight of the object, and the larger the particle, the faster the sedimentation. For particles smaller than a few micrometers 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 by gravity alone. The smaller the particles, the slower the sedimentation, and the more severe the diffusion phenomenon. Therefore, it is necessary to use a centrifugal machine to generate a strong centrifugal force in order to force these particles to overcome the diffusion to produce a settling motion.
  The choice of refrigerated centrifuge shall be based on the size and concentration of solid particles in the suspension (or emulsion), the difference in density between solids and liquids (or two liquids), the viscosity of the liquid, the characteristics of the filter residue (or sediment), and the requirements for separation. The comprehensive analysis is carried out to meet the requirements for the moisture content of the filter residue (sludge) and the clarity of the filtrate (separation liquid), and which type of refrigerated centrifuge is initially selected. Then, the frozen large-capacity centrifuge determines the type and specifications of the refrigerated centrifuge according to the processing amount and the automation requirements for the operation, and finally verified by actual tests.