Centrifugation is a mechanical process that relies on centrifugal force to separate mixed substances and fluids of varying density. Centrifuges generate these forces by spinning the fluid in a circular motion around a fixed axis. The centrifugal force pushes the heavier material outwards and allows less dense substances to gravitate inwards towards the centre of the circle. The magnitude and effect of the force are mainly influenced by the speed, direction and angle of rotation.
Types of Centrifuges
Centrifuges have a wide range of designs and applications, which means there are several methods used to classify them. These methods include: mode of operation, speed, size and the magnitude of force generated.
However, the selection between manual and automatic centrifuges is the first step when deciding which machine is best for you. Here are some of the factors that you should consider when choosing between a manual and automatic centrifuge.
- Budget
- Volume of workload
- Frequency of operation
- Access to electricity
- Nature of substances to be separated
Manual Centrifuges
Manual centrifuges are among the oldest designs available, dating as far back as the early 20th century when they were used to separate skimmed milk from the cream. Nevertheless, manual centrifuges are still rather popular today. If you decide to use manual centrifuges, you will need to choose between Hand-operated and manually maintained centrifuges.
Hand-operated centrifuges typically have a lever or handle that is rotated manually to spin the centrifuge. The manual rotation is mechanically translated to higher speeds inside the centrifuge to generate the magnitude of centrifugal forces necessary for separation.
These hand-operated centrifuges are useful for simple separations that do not need massive forces. They can be used for simple lab tests such as anaemia diagnosis in settings with limited access to electricity.
Manually maintained centrifuges are classified as manual due to the method in which they are cleaned and maintained. These centrifuges use electric motors to run the centrifugation process and can generate the strong forces necessary for complex operations.
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