A machine that uses centrifugal force to separate substances of different densities, such as solids from liquids or different liquids; includes devices like hydroextractors and plasma separators

to rack one's brains for schemes; to try every possible means or plot to achieve an end

To try every possible means or tax one's ingenuity to the limit in order to achieve a goal

to waste one's efforts on a scheme; to plot in vain; to exhaust one's ingenuity to no avail