Today in 1965, US Patent 3219319 A was issued, an invention of Michael Edward Ash, assigned to Guinness Son & Co. Ltd., for his “Concentration Control Apparatus for a Continuous Flow System.” There’s no Abstract, although in the description it includes this summary:

This invention relates in general to continuous flow systems of the kind in which liquid suspensions comprising a mechanical dispersion of sedimentable particles in a liquid of relatively lower specific gravity, are caused to flow through a processing vessel or series of vessels.