Centrifuge Types, Applications And Other Factors to Consider Before You Buy

Hopefully you're here because you have an application that requires the use of a Centrifuge, or you're getting ready to purchase a centrifuge but you're not quite sure which type will best meet your needs. If this sounds like you, then you've come to the right place. After reading this article, you will learn about the different types of centrifuges, why they are useful, and how they work so you can choose the most appropriate centrifuge for your lab experiments!

Centrifuge

How do centrifuges work?

Centrifuges work by separating two materials of different densities. They are best suited for separating materials with similar densities; or when insoluble particles are present in the dissolved solution. A common misconception is that centrifuges utilize centrifugal force. In fact, all centrifuges work using the sedimentation principle. The sedimentation principle means that the acceleration of the rotor causes centripetal forces to act on the rotor and the centrifuge tube. This causes the denser material in the centrifuge tube to be forced outward in a radial direction. This also causes the lighter particles to be displaced and move toward the center. Many particles can become "stuck" in the bottom of the centrifuge tube, especially when using a laboratory centrifuge. These particles are often referred to as pellets and the clarified solution is referred to as the supernatant.

While you may set your centrifuge to revolutions per minute or RPM, it is the acceleration that is the important factor. This is because the two rotors may have different diameters but the same speed. In this case, the acceleration of the two rotors will not be the same. Because acceleration is the product of the radius and the square of the angular momentum, the size of the rotor becomes a contributing factor. Therefore, the relative centrifugal force is used as a standard unit and is measured in g.

Applications of Centrifuges

Centrifuges can be used for a variety of applications, as there are many different types of centrifuges on the market today. Some common applications for centrifuges are listed below:

Separating mixtures with close densities

Separating immiscible liquids

Suspension of solids from sediments

Separation of blood

Separation of insoluble particles 

Separation of isotopes

Gravity simulation environment for astronauts

Separation of frost

Washing machine rotation function

Separation of waste water sludge

Material synthesis in a high gravity environment

And of course there are many more. Any application that requires the separation of 2 components will find the centrifuge a useful tool.

What types of centrifuges are available?

There are many types on the market today, the two most important factors being rotor speed and centrifuge size.

Let's discuss Laboratory Centrifuges. Normal laboratory centrifuges exhibit all the normal performance mentioned earlier and are the standard type of centrifuges available. Normal centrifuges are the larger centrifuges you will find in your laboratory and are called floor model centrifuges. These types of centrifuges require more space than benchtop centrifuges, but they can hold more material because of the larger rotors and centrifuge tubes. Floor model centrifuges come with refrigeration and can be set at temperatures between -20°C and +40°C. RCF can also be up to 100,000 g. Common centrifuges are particularly useful when working with DNA, RNA, antibodies, viruses or proteins.

However, if space is a constraint, then a benchtop microcentrifuge or benchtop ultracentrifuge would be more beneficial. However, they can only hold small amounts of material, so they are best used for applications with small sample volumes. Benchtop centrifuges can be purchased with built-in refrigerators, but not all models include them. In many cases, refrigeration protects the sample from thermal degradation caused by rotor rotation, so it is recommended to purchase a refrigerated centrifuge when working with sensitive samples. In general, benchtop centrifuges can be used for a variety of applications, including DNA, RNA and protein research, tissue culture and cell culture.

We also offer Screen Centrifuges, so please feel free to contact us if you need one.