Laboratory Equipment

What is a Centrifuge and How Does It Work?

A centrifuge is a commonly used tool in research labs across the world. In fact, it is one of the most widely used research techniques in many areas of science including medicine, biochemistry and molecular biology.

A centrifuge uses the process of centrifugation to separate components of a mixture that is complex. This machine spins laboratory samples at high speeds. This allows the components of the mixture to be exposed to centrifugal force - this causes denser particles to separate from the axis of rotation. Lighter particles then move toward this axis. Pellets, small particles of sediment, are pushed to the bottom of the tube. The remaining solution, or the supernatant, can then be analyzed or processed further.

What is the Purpose of a Centrifuge?

Cells and particles in liquid suspension will, in time, settle at the bottom of the container it is placed in due to the force of gravity. In research labs, the amount of time that will cause these natural separations can be lengthy. Some particles that are extremely small will not separate at all in a solution. 

Thus, the need for a centrifuge and use of high centrifugal force. The centrifugal force will cause these particles to move away from the axis when a suspension is rotated at a specified amount of rotations per minute (RPM). 

The force on these particles when compared to gravity is called the Relative Centrifugal Force (RCF). Example, when the RCF is equal to 500 x g, this means that the centrifugal force that was applied is 500 times greater than the Earth’s gravitational force. 

Features and Benefits of Using a Centrifuge

There are many features and benefits to using centrifugation:

• It is an easy way to separate out substances at a faster rate than they would naturally.
• The machine itself is small in size so it is easy to place within a work space.
• There is continuous dewatering in the unit which can reduce olfactory nuisances and this in turn, reduces the cost of deodorising the work space.
• The machine is compact and easy to install, requires no cleaning since it washes automatically.
• Typically, the process is unmanned and safety mechanisms come standard with the equipment.
• The automated system is reliable due to the sludge concentration sensors.
• It is suitable for many different types of liquid, including the most difficult, oily liquids.
• Maintenance cost is low and the cost to install one of these machines is low as well.
• In most cases, the machine can be used as both a separator or a mixer.

Top Uses of a Centrifuge

Many of the laboratory centrifuges are used in biology, biochemistry, chemistry and clinical medicine for isolating and separating immiscible liquids and suspensions.

Other laboratories use these machines to separate blood. Clinical diagnosis and pharmacogenetics use centrifuges in order to prepare DNA.

Specialized types of centrifuges are used in biological and medical laboratories in order to concentrate cells to examine them microscopically.

Other types of centrifuges can be used in aeronautics, geotechnical testing, material synthesis and commercial applications.

Different Types of Centrifuges

There are several different types of centrifuges. The differences in them will be listed below.

Clinical Centrifuges

A clinical centrifuge is generally low-speed and is used for the production of PRP (platelet rich plasma) and PPP (platelet poor plasma). These machines are also widely used in hospitals and research labs for the separation of blood samples, serum, urea and other common applications.

Microcentrifuges

A microcentrifuge is typically for small sample sizes. This machine is ideal for HPLC (high performance liquid chromatography) and microfilter cell separations. These are specifically designed to hold less than 5.0 mL in each tube.

Hematocrit Centrifuge

A hematocrit centrifuge is used for the separation of blood and solutions that are in micro volumes. They are also able to determine the volume fractions of erythrocytes, the red blood cells, in blood. These machines will provide the HCT (hematocrit values) that are used for testing in genetics, biochemistry, immunity, general clinical tests and blood separation.

Laboratory Centrifuge

A laboratory centrifuge is a commonly used machine that is designed to separate samples of liquid at high speeds. They offer a wide range of applications that are used in hospitals, research facilities and other laboratories. The main purpose of these is to separate the solids from the material samples. Some also have multiple capacities which can include a high speed refrigerated centrifuge.

Geotechnical Centrifuge

These centrifuges are able to test scale models of geotechnical engineering systems. This can be building or bridge foundations, earth retaining structures and man-made or natural slopes. Other uses can include testing tunnel and sealwall stabilities, contamination migration and explosive cratering.

Lab Pro offers a large variety of centrifuges. For over 40 years, Lab Pro Inc. has been committed to delivering the highest quality chemicals, distance learning kits, lab supplies, and cleanroom PPE apparel to medical device companies and laboratories worldwide. To learn more, visit the biggest Lab Supply showroom in California, or contact us online or at 888-452-2776.