That sounds like density centrifugation...So, a centrifuge?

A centrifuge has holes to insert the centrifuge tubes in, a cap to secure the tubes inside, and a lid to protect both the samples and experimenter in case of malfunction. There is also typically a way to set the centrifuge speed and a power switch to turn the centrifuge on and off.

Antonin Prandtl, however Gustof de Laval invented the first "Modern" centrifuge.

http://en.wikipedia.org/wiki/Centrifuge

centrifuge is a system which is used to separate the water from the diesel.

Using centrifuge: brill idea