A hollow fiber permeator is described which permits counter-current flow in the passage of feed/retentate and permeate-sweep streams. The permeator comprises a bundle of hollow fibers compartmentalized using a series of concentric shells or a spiral wrap extending the entire length of the hollow fibers. The rings or spiral wrap are perforated along the top and bottom to permit even flow distribution through each of the compartments defined by the concentric rings or spiral wrap so that the linear flow rate down the length of the permeator is similar for each compartment.