SIGNIFICANT APPLICATIONS OF CENTRIFUGES

  • Isolating suspensions

    Simple centrifuges are used in chemistry, biology, and biochemistry for isolating and separating suspensions. They vary widely in speed and capacity. They usually comprise a rotor containing two, four, six, or many more numbered wells within which the samples, contained in centrifuge tubes, may be placed.

  • Isotope separation

    Other centrifuges, the first being the Zippe-type centrifuge, separate isotopes, and these kinds of centrifuges are in use in nuclear power and nuclear weapon programs.

    Gas centrifuges are used in uranium enrichment.

    The heavier isotope of uranium (uranium-238) in the uranium hexafluoride gas tends to concentrate at the walls of the centrifuge as it spins, while the desired uranium-235 isotope is extracted and concentrated with a scoop selectively placed inside the centrifuge. It takes many thousands of centrifugations to enrich uranium enough for use in a nuclear reactor (around 3.5% enrichment), and many thousands more to enrich it to weapons-grade (above 90% enrichment) for use in nuclear weapons.

  • Aeronautics and astronautics

    The 20 G centrifuge at the NASA Ames Research Center

    Human centrifuges are exceptionally large centrifuges that test the reactions and tolerance of pilots and astronauts to acceleration above those experienced in the Earth’s gravity.

    The US Air Force at Holloman Air Force Base, New Mexico operates a human centrifuge. The centrifuge at Holloman AFB is operated by the aerospace physiology department for the purpose of training and evaluating prospective fighter pilots for high-g flight in Air Force fighter aircraft.

    The use of large centrifuges to simulate a feeling of gravity has been proposed for future long-duration space missions. Exposure to this simulated gravity would prevent or reduce the bone decalcification and muscle atrophy that affect individuals exposed to long periods of freefall.

    The first centrifuges used for human research were used by Erasmus Darwin, the grandfather of Charles Darwin. The first large scale human centrifuge designed for Aeronautical training was created in Germany in 1933.

  • Geotechnical centrifuge modeling

    Geotechnical centrifuge modeling is used for physical testing of models involving soils. Centrifuge acceleration is applied to scale models to scale the gravitational acceleration and enable prototype scale stresses to be obtained in scale models. Problems such as building and bridge foundations, earth dams, tunnels, and slope stability, including effects such as blast loading and earthquake shaking.

  • Commercial applications

    Sugar centrifugal machines, to separating sugar crystals from the crystallized syrup, or mother liquor.
    • Centrifuges with a batch weight of up to 2,200 kg per charge are used in the sugar industry to separate the sugar crystals from the mother liquor.
    • Standalone centrifuges for drying (hand-washed) clothes – usually with a water outlet.
    • Washing machines
    • Centrifuges are used in the attraction Mission: SPACE, located at Epcot in Walt Disney World, which propels riders using a combination of a centrifuge and a motion simulator to simulate the feeling of going into space.
    • In soil mechanics, centrifuges utilize centrifugal acceleration to match soil stresses in a scale model to those found in reality.
    • Large industrial centrifuges are commonly used in water and wastewater treatment to dry sludges. The resulting dry product is often termed cake, and the water leaving a centrifuge after most of the solids have been removed is called centrate.
    • Large industrial centrifuges are also used in the oil industry to remove solids from the drilling fluid.
    • Disc-stack centrifuges used by some companies in Oil Sands industry to separate small amounts of water and solids from bitumen.
    • Centrifuges are used to separate cream (remove fat) from milk.