According to About Mechanics:
A centrifugal filter is a type of barrier that can be used to separate materials after they are spun in a centrifuge. When a centrifuge is outfitted with a filter, high density solids or liquids can be effectively removed from low density liquids. In many industries, a centrifugal filter is used to separate waste products from certain liquids, which can then be reused by the company.
Materials that are placed into a centrifuge are spun around an axis in the center of the machine. The denser materials are forced to the outer edge of the container while the lighter materials float toward the axis. When equipped with a centrifugal filter, the heavier and lighter materials are forced into different containers. Different size filters can be used to separate different sized particles from one another.
A centrifugal filter is usually used to separate solid matter from a liquid suspension. This allows the liquid portion of the material to be recycled. Solid matter that is removed from a liquid through a centrifugal filter usually escapes in the form of slurry. The wet material can then be dried, either in a special holding container within the centrifuge or in a separate container until it can be disposed.
Centrifugal filters are used by a number of different industries. They can be used to clarify waste oil, clean out glass or ceramic grinding fluids, or remove small particles of metal from liquids. The liquid remaining after the centrifugal filtration can often be used again once it is clean. This cuts down on waste materials and reduces a company’s expenses.
A relatively simple instrument, the centrifuge has been used for hundreds of years to separate materials of different densities. The centrifuge spins anywhere from a couple hundred to a many thousand revolutions per minute. The force acting on materials placed in a centrifuge can be thousands of times the force of gravity. This level of force is what allows heavier materials to move to the outside of the container while lighter materials move toward the center.
The first known use of the centrifuge was to separate milk from cream. Early centrifuges were hand powered, though they were still able create a force equal to many times the force of gravity. In 1869, laboratory use of the centrifuge led to the discovery of nucleic acids, which separate from organic cells. Today, centrifuges are most commonly used in medical and biological laboratories.