What is Centrifuge: Definition and 78 Discussions

A centrifuge is a device that uses centrifugal force to separate various components of a fluid. This is achieved by spinning the fluid at high speed within a container, thereby separating fluids of different densities (e.g. cream from milk) or liquids from solids. It works by causing denser substances and particles to move outward in the radial direction. At the same time, objects that are less dense are displaced and move to the centre. In a laboratory centrifuge that uses sample tubes, the radial acceleration causes denser particles to settle to the bottom of the tube, while low-density substances rise to the top. A centrifuge can be a very effective filter that separates contaminants from the main body of fluid.
Industrial scale centrifuges are commonly used in manufacturing and waste processing to sediment suspended solids, or to separate immiscible liquids. An example is the cream separator found in dairies. Very high speed centrifuges and ultracentrifuges able to provide very high accelerations can separate fine particles down to the nano-scale, and molecules of different masses. Large centrifuges are used to simulate high gravity or acceleration environments (for example, high-G training for test pilots). Medium-sized centrifuges are used in washing machines and at some swimming pools to draw water out of fabrics. Gas centrifuges are used for isotope separation, such as to enrich nuclear fuel for fissile isotopes.

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  1. K

    Can G-Commanded Centrifuge Motion Be Controlled with Additional Constraints?

    Hello. A few of us at my company have been trying to solve this problem for a few weeks now, without success, and so now I turn to the brilliant minds of the people who frequent this forum for help :-) We operate a centrifuge that spins between 1.4 G and 9 G. The command that we send to our...
  2. U

    How to get the centrifuge on LEO?

    How to get the Mars space ship's centrifuge (diameter: ~20 meters) on LEO with Ares V? The radiation shield (liquid water) between centrifuge's hollow walls has mass of 160 metric tonns, so probably the centrifuge has to be shoot on LEO without the water. Ares V's payload is "only" 130 metric...
  3. I

    Calculate Separation Time for Oil Particles with Centrifuge

    I am building a centrifuge to separate solid particles from oil and would like to be able to calculate the separation time for given particles at various relative “G” forces. From what I know (or think I know) the forces involved are the mass of the particle (relative to the oil) multiplied by...
  4. D

    Determine Centrifuge Torque w/o Acceleration

    I am trying to determine the torque exerted by a motor running a centrifuge at constant speed. How do you determine torque when there is no acceleration? I know it's there somewhere...
  5. Mentz114

    Centrifuge Tech: Parameters of Best Centrifuges Today?

    I was wondering what are the parameters of best centrifuges that can be built today, i.e. the greatest angular velocity*radius. I can see there are separation centrifuges available that do 6500 rpm with chamber diameter of 28cm. Is it possible to improve on this ? This is related to...
  6. D

    How relative density depends on R in a Centrifuge

    Homework Statement A dilute solution of macromolecules at temperature T is placed in a centrifuge rotating with angular velocity w. The mass of each molecule is m. The equivalent centrifugal force on each particle in the rotating frame of reference is mw^2r, where r is the radial distance...
  7. M

    Centripetal acceleration centrifuge problem

    [SOLVED] centripetal acceleration problem Homework Statement Find the centripetal acceleration at the top of a test tube in a centrifuge, given that the top is 5.0 cm from the axis of rotation and that its linear speed is 76 m/s.Homework Equations Ac = v^2/r The Attempt at a Solution So...
  8. P

    Ford F150 Tow Hooks: 10G's of Force?

    In the Ford F150 commerical that debuted during the Superbowl (), Ford says that it subejcted the tow hooks on the truck to 6g's of force. I timed the period of the truck during the portion in which the narrator is visible on the screen and got 1.80 seconds roughly. I read online that the...
  9. D

    Vacuum vs. Centrifuge - equivalence

    I've been using a vacuum system to filter solutions. I would like to move it over to a centrifuge. I have been having trouble equating the pressure in the vacuum to the required amount of force required by a centrifuge. Can someone help me out with the math? I'm looking a the vacuum pressure in...
  10. P

    How Many Revolutions Does a Centrifuge Make in 240 Seconds?

    [SOLVED] Centrifuge Revolutions? Homework Statement A centrifuge accelerate from rest to 15,000 rpm in 240s. Through how many revolutions did it turn in this time? Homework Equations am i approaching this problem correctly? The Attempt at a Solution 15000rev/m (1m/60s) (240s) =...
  11. A

    Zinc Ferrite Nano-Particles: Centrifuge RPM Calculation

    Hey, I've been reading on this site for a week of so now, and just wanted to say thanks for all your contributions. Very helpfull! My question is, I am making zinc ferrite nano-particles and i was wondering at what RPM i should set the centrifuge to, so that the zinc ferrite comes out of...
  12. P

    Calculating Force for 5.0g Object at 11000 g's

    Force required to accelerate 5.0g object at 11000 g's. (in a centrifuge) But it does not give me rpm or diameter so how can i calculate the force? Im assuming it really doesn't matter that its in a centrifuge? Any leads would help
  13. I

    Orbit, and Centrifuge questions

    Homework Statement Communications satellites are placed in a circular orbit where they stay directly over a fixed point on the equator as the Earth rotates. These are called geosynchronous orbits. The altitude of a geosynchronous orbit is 3.58 x10^7 m a)What is the period of a satellite in...
  14. A

    Acceleration and rotation of centrifuge

    Homework Statement A typical laboratory centrifuge rotates at 4200 rpm. Test tubes have to be placed into a centrifuge very carefully because of the very large accelerators. a.) What is the acceleration at the end of a test tube that is 11 cm from the axis of rotation? b.) For comparison...
  15. A

    How Does Gravity Affect Centrifuge Operations on Mercury?

    Homework Statement A laboratory centrifuge on Earth makes n rpm (rev/min) and produces an acceleration of 5.90 g at its outer end. a. What is the acceleration (in g's) at a point halfway out to the end b. The centrifuge is now used in a space capsule on the planet mercury, where gmercury...
  16. N

    Centrifuge acceleration expressed in terms of gravity

    A Biophysicist wants to separate sub-cellular particles with an analytic ultra-centrifuge. The biophysicist must determine the magnitude of the centripetal acceleration provided by the centrifuge at various speeds and radii. Calculate the magnitude of the centripetal acceleration at 8.4 cm...
  17. S

    Centrifuge question (Stat Mech)

    A circular cylinder of radius R rotates about hte long axis with angular velocity omega. The cylinder contains an ideal gas of atoms of mass M at temperature tau. Find the expression for the dependence of the concentration n(r) on the radial distance r from the axis in terms of n(0) on the axis...
  18. C

    What's the highest rpm centrifuge on earth.

    What's the highest rpm centrifuge on earth.
  19. M

    Uniform Circular Motion of centrifuge

    Hi there. I need some help with this question. Can anyone help me... A centrifuge is a device in which a small container of material is rotated at a high speed on a circular path. Suppose the centripetal acceleration of the sample is 6.25 X 103 times as large as the acceleration due to...
  20. P

    Does a Centrifuge distort atomic geometry?

    Greetings. I know that a centrifuge can "seperate" different elements by virtue of centrifugal force, but what effect does a centrifuge have on the atomic geometry of individual atoms? That is, since the nucleus of an atom is generally more massive than the collective orbiting electrons, does a...
  21. O

    Solve Centrifuge Problem with Calculus & Angular Velocity

    I have a problem with a small physics problem. It requires some knowledge of calculus which I don't yet posses I am looking here for ideas. The problem states that there is a centrifuge tube with a length 12cm that is caused to spin by a rotating arm with lengt 8 cm. The tube is filled with 10...
  22. T

    Does a Muon Centrifuge Experiment Show Gravitational Time Effects?

    I'm speaking of the Muon decay experiment which showed no additional gravitationally related time effects in a centrifuge... Firstly does anyone have a real reference for the experiment? All I find are offhand mentions of it. The only identifying info I've gotten on it was that it was in 1966...
  23. J

    Centrifuge Revolution Calculation

    A sample of blood is placed in a centrifuge of radius 16.0 cm. The mass of a red blood cell is 3.0e-16 kg, and the magnitude of the force acting on it as it settles out of the plasma is 4.0e-11 N. At how many revolutions per second should the centrifuge be operated? I can figure out the...
  24. wasteofo2

    Impossible to centrifuge salt out of water?

    I've been told (by my high school chemistry teacher, which obviously means it isn't necessarily true), that when salt dissolves in water, that you cannot centrifuge it out. I understand that you can't centrifuge it out like you would sugar, or something that doesn't ionize, but it seems to me...
  25. S

    Exploring Forces of Liquid in a Centrifuge

    Hey, As part of an investigation, I constructed a basic centrifuge consisting of a fast rotating beaker filled with liquid. I have observed that an increased angular velocity forces the liquid out of the centre and further up the sides of the centrifuge, as expected. However, I am having...
  26. J

    Can a Centrifuge Experiment Demonstrate Reciprocity in Special Relativity?

    Hi all, In another forum, I've been exploring the idea of an experiment to demonstrate what has been referred to as 'reciprocity' in SR. That is, the mutual observation of time dilation by two observers with relative velocity(Bob says Mary's clock is dilated while Mary says Bob's clock is...
  27. B

    Angular Velocity of a centrifuge

    An astronaut is being tested in a centrifuge. The centrifuge has a radius of 10.5 m and, in starting, rotates according to Θ(theta) = 0.13t^2, where t in seconds gives Θ in radians. When t = 5.0 s, what are the astronaut's angular velocity? What is the astronauts linear speed? What is...
  28. M

    Calculating Revolutions/Minute for Centrifuge at 4.62 cm Radius

    ok, you are using a centrifuge. the centripetal acceleration of the sample is 5.05E3 times larger than the accelleration due to gravity. how many revolutions/minute is the sample making if it is located at a radius of 4.62 cm from the axis of rotation? i think i use: centripetal accellearion...
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