An apparatus and method for semi-permeable membrane based blood filtrationfeaturingcontrolled filtrate to non-filtrate separation ratio, self-regulating pressureintensification and energyrecovery means and wherein basic embodiments can function without the need forvalves or anyother control means. These capabilities are provided for by a cooperating,positive displacementpump and motor set based apparatus wherein the greater volumetric displacementof an upstreamhydraulic pump cannot be fully taken up by a lesser volumetric displacementdownstream hydraulicmotor as they operate synchronously within the same series circuit. Thiscauses pressureintensification within the fluid circuit located between the pump and motorsuch that a volume offluid essentially equal to the pump to motor volumetric displacementdifferential is compelled toflow out of the pressurized circuit by passing through or permeating the semi-permeable membranelocated within it.
