Introduction to Centrifuges
Centrifuge is a machine that utilizes centrifugal force to separate the components of liquid and solid particles or liquid and liquid mixtures. Its working principle is mainly based on the centrifugal force generated during the rotation of the object, which makes the different materials to be separated to be accelerated and separated. The following is a detailed description of centrifuges.
Classification：
Filtration centrifuge: through the centrifugal force generated by the high-speed centrifugal drum (with the appropriate filter material) will be a mixture of solid-liquid liquid phase accelerated out of the drum while the solid phase to stay in the drum, to achieve the effect of separation of solids and liquids
Sedimentation centrifuge: Through the powerful centrifugal force generated by the high-speed rotation of the rotor, accelerate the settling speed of the different specific gravity components (solid or liquid phase) in the mixture, and separate the substances with different settling coefficients and buoyancy densities in the samples.
Scope of application：
Centrifuges are widely used in chemical, petroleum, food and pharmaceutical, mineral processing, coal, water treatment and shipbuilding sectors.
In the chemical and petroleum industries, centrifuges are often used to separate solid particles from liquids in floating liquids.
In the food and pharmaceutical industries, centrifuges can be used to separate liquids of different densities from emulsions, such as separating cream from milk.
Selection Considerations：
Selection of centrifuges, need to be based on the suspension (or emulsion) in the size and concentration of solid particles, solids and liquids (or two liquids), the density difference between the liquid viscosity, as well as filtration residue (or sediment) characteristics of the selection of models.
Centrifuge performance and configuration is also an important factor to consider when selecting the type, including the performance of the host, the type and number of rotors, centrifuge tubes and other accessories such as the configuration.
Use of centrifuges
The following are the steps and precautions for the use of centrifuges
1.Use steps.
Turn on the centrifuge power switch and enter the standby state. Choose a suitable turn hole, and make sure that the liquid contained in the centrifuge tube does not exceed 2/3 of the total volume of the centrifuge tube. Check whether there is any liquid residue in the rotary head, and if there is any, it should be wiped clean and kept dry and clean.
Strictly leveling, put the balanced centrifuge tube symmetrically into the rotary hole, the error of centrifuge tube balancing should be within 0.1gl.
Set the rotational speed, temperature and time, lower the centrifuge cover door and check whether the cover is secure, then start the centrifuge. When the rotor stops rotating, open the cover to remove the centrifuge tube. Turn off the power button when the operation is complete and make a record.
2.Precautions.
During the centrifugation process, the operator shall not leave the centrifuge room, and shall stop the machine immediately for inspection once an abnormal situation occurs.
When the centrifuge is pre-cooled, the centrifuge cover must be closed: after centrifugation, the rotor head should be placed upside down on the experimental bench, the residual water in the chamber should be wiped dry, and the centrifuge cover should be in the open state.
When the rotor head is pre-cooled, the cover should be placed on the platform of the centrifuge or on the experimental bench, and should not be left unscrewed and floating on the rotor head to prevent accidents caused by false start.
The cover of the rotary head should be touched with a finger after tightening to see if there is any gap between the rotary head and the cover, and if there is any gap, it should be re-tightened until it is confirmed that there is no gap before starting the centrifuge.
Do not use shoddy, aged, deformed or cracked centrifuge tubes.
Routine safety checks should be carried out after using the centrifuge on holidays and at night.
Centrifuge tubes must be placed symmetrically in the casing. If only one sample tube is used, the other should be replaced by an equal mass of water to prevent vibration of the machine.
The centrifuge should be switched off at the end of the separation and the lid opened only after the base has stopped rotating to remove the sample, without forcing it to stop moving.