US Patent 7410587 Liquid handling for filtration and preparative chromatography

A method and system are provided for high-precision separation of pharmaceutical or biotechnology liquids. The separation can be in accordance with direct flow filtration, tangential flow filtration or preparative chromatography. Movement of the pharmaceutical or biotechnology liquid within a flow path is controlled according to a selected pattern. Selected patterns include automatically and progressively increasing the flow rate within the unit, automatically and progressively increasing the pressure within the unit or initially proceeding according to a relatively high constant flow rate and switching to a relatively high constant pressure at a time when a given parameter is attained.