Method of winding hollow fiber membranes

Abstract

Bundles of hollow filament membranes suitable for use in fluid separation, such as in the separation of air into gases more concentrated in oxygen and nitrogen are made in a cylindrical form and annular cross-section with multiple filaments of each layer lying in generally parallel helical paths at a common angle to the axis of symmetry of the bundle. Continuous lengths of filaments are laid down on the core while same is rotated first in a 'forward' sense and the filament lay-down point is traversed from a first end of the core to the second, and then in a 'reverse' sense while the filament lay-down point is traversed from the second end to the first. Reversing of the direction of core rotation and filament end-to-end traversal is repeated with said reversing controlled in such a manner that the path of the filament returning from either end to the other is displaced incrementally from that of the filament portion laid down in the immediately preceding traversal. Lay-down of filament is repeated until a plurality of segments of filament all sharing the same helix angle and direction have formed a thin annular layer. The instant method can be precisely controlled to obtain bundles of desired packing density with consequent improved flow of fluid within the shell side of the bundle.