Process for manufacturing a sterilizing filter

A process for the production of a sterilizing filter comprising a plurality of hollow fiber membranes, comprising

• a) producing a continuous hollow fiber membrane filament having an inner diameter of from 2.8 to 4.0 mm, an outer diameter larger than 3 mm and smaller than 4.5 mm, and a ratio of inner diameter to wall thickness larger than 10 by a continuous solvent phase inversion spinning process;
• b) cutting the continuous hollow fiber filament into segments having a predefined length by a rotating blade while the hollow fiber membrane is still wet;
• c) collecting the hollow fiber membrane segments, transferring them into a rinsing tube, and rinsing them with purified water to remove residual leachable constituents;
• d) optionally, centrifuging the membranes within the rinsing tube;
• e) drying the hollow fiber membrane segments within the rinsing tube;
• f) optionally, cutting the hollow fiber membrane segments to a predefined final length;
• g) sealing one end of the hollow fiber membrane segments;
• h) transferring a number of hollow fiber membrane segments required for the sterilizing filter to a disc having the corresponding number of bores with a diameter matching the outer diameter of the hollow fiber membranes, threading the open ends of the hollow fiber membrane segments into the bores of the disc and welding them to the wall of the bores by heat welding;
• i) transferring the disc comprising the hollow fiber membranes into a housing which comprises a header component with a fluid inlet and a tubular component with a fluid outlet;
• j) joining the disc and the housing by Laser welding with an IR Laser and sealing the housing.