A centrifuge is a device used to separate liquids from solids by spinning. Long ago, people saw that gravity could eventually separate a sediment from a liquid or separate two liquids which do not mix. The heavier element within a container would descend, while the lighter element would rise to the surface. This process was extremely slow if left up to nature alone and was also wasteful, as evidenced by the way farmers used to separate cream from milk. They would let whole milk stand for several hours until the lighter cream rose to the top. They then skimmed off the cream with a wooden spoon, but as much as 40 percent of the cream was left in the milk. Later, small strainer dishes were used to extract the cream, yet this too was a slow and tedious process.

In 1877, Swedish inventor Carl Gustaf Patrik de Laval introduced a...