The principle of centrifugation
The principle of centrifugation refers to the fact that when an object is rotating or in a centrifugal force field, it will be affected by centrifugal force, causing the object to move away from the axis of rotation or the center of the force field. This centrifugal force is an inertial force generated by the inertia of the rotating object itself. Its magnitude is proportional to the mass of the object, the square of the rotation speed, and inversely proportional to the rotation radius. Centrifugal action is widely used in various fields. Its core is to use centrifugal force to separate, extract or pump substances. Centrifugation is one of the most versatile processes in various industries, allowing for the separation, extraction, or pumping of substances. It works by utilizing the centrifugal force generated by the rotation speed and rotation radius of an object. This powerful inertial force is able to effectively move objects away from the axis of rotation or the center of the force field, making it a widely applicable tool for many purposes.
In a centrifuge, the drum (a cylinder rotating at high speed around its own axis) is usually driven by an electric motor. After the floating liquid (or emulsion) is added to the drum, it is quickly driven to rotate at the same speed as the drum. Due to the different specific gravities of the solid and wave phases, they will produce different centrifugal inertial forces, resulting in the solid phase particles being deposited on the inner wall of the drum, while the liquid phase settles in the inner layer, and then discharged from different outlets to achieve the purpose of separation.
Application of centrifugation
The centrifugal principle is widely used in various fields, including but not limited to the following aspects:
Industrial field:
- Chemical and pharmaceutical: used to separate solids and liquids in mixtures, such as drug purification, catalyst recovery, etc.
- Oil and natural gas: used to separate oil, water, gas and other components during oil extraction and processing.
- Food and beverage: such as cream separation and juice clarification in dairy processing.
Biomedical field:
- Cell and molecular biology: used to separate cells, viruses, proteins, nucleic acids and other biomacromolecules.
- Hematology: Through centrifugal separation, blood can be separated into plasma and red blood cells, which are further used for blood pathology detection and clinical diagnosis.
Environmental protection:
- Wastewater treatment: Use centrifuges to treat wastewater and remove floating objects and solid particles.
- Solid waste treatment: In the process of garbage disposal, centrifugal technology can be used to separate recyclable materials and hazardous materials.
Aerospace:
- Rocket propulsion system: The pump in a liquid rocket engine uses the centrifugal principle to transfer liquid fuel or oxidizer from the tank to the combustion chamber.
- Spacecraft separation mechanism: During the launch and return of a spacecraft, the centrifugal principle is used to separate the spacecraft and the launch vehicle.
Other fields:
- Agriculture: Centrifugal pumps are used for irrigation and drainage of farmland. Transportation: Centrifugal force can affect the performance of tires, such as adjusting their stability and grip.
Types of Centrifugation
Centrifugation methods are mainly divided into two categories: preparative and analytical
Preparative centrifugation:
It is mainly used to separate certain particles and is the most common type of centrifugation in molecular or cell biology laboratories. Among them, differential centrifugation is an important method of conventional preparative centrifugation. A widely-used technique in laboratories, differential centrifugation effectively separates particles and is essential in molecular and cell biology. With advanced precision, this method is a fundamental tool for preparing samples for further analysis.
Analytical centrifugation:
It is mainly used to understand the physical properties of separated particles, such as density, sedimentation coefficient, etc.