Patent ID: 7410587

Claim:
A method for high-precision separation of pharmaceutical or biotechnology liquids by direct flow filtration, comprising: providing within a reservoir a pharmaceutical or biotechnology liquid having target bio-molecules dissolved or suspended within a carrier liquid; controlling movement of the pharmaceutical or biotechnology liquid within a flow path which includes moving the liquid from the reservoir to a direct flow filtration separation unit having an inlet and an outlet; monitoring pressure at a location along the flow path; passing the liquid containing target bio-molecules through the inlet of the direct flow filtration separation unit to separate at least some of the target bio-molecules therefrom; controlling movement of the liquid containing target bio-molecules to the separation unit, said controlling movement including: initially moving the liquid containing target bio-molecules to the separation unit at a low pressure rate of flow of said liquid within a constant flow rate range during a constant flow rate direct flow filtration stage, selecting a switching scheme by which the constant flow rate stage for the liquid containing target bio-molecules ceases and a constant pressure direct flow filtration stage within the flow path is initiated at a switching point that is reached at substantially the same time at which the constant flow rate direct flow filtration stage ceases, defining the switching point according to achievement of a predetermined high pressure value at a pressure monitoring location within the flow path, and automatically ceasing, at the switching point, the constant flow rate direct flow filtration stage by modulating flow of the liquid and allowing the flow rate to reduce toward a low flow rate that is slower than the constant flow rate range, and then automatically increasing the pressure within the flow path from said low pressure toward the constant pressure range within the flow path, thereby initiating said constant pressure direct flow filtration stage at approximately the switching point, said constant pressure range being greater than said low pressure, and said ceasing and initiating being according to said switching scheme; and collecting target bio-molecules as a purified pharmaceutical or biotechnology product of purified target bio-molecules by separating same from the carrier liquid and undesirable contaminants.