Process for making a filtration and/or diffusion device

A process for the production of a filtration and/or diffusion device comprising a bundle of hollow fiber membranes disposed within a tubular housing, the process comprising the steps of:

• sealing a first end of the bundle of hollow fiber membranes by dipping the first end of the bundle into a melt of thermoplastic resin and allowing the melt to solidify;
• sealing a first end of the tubular housing corresponding to the first end of the bundle by dipping the first end of the tubular housing into a melt of thermoplastic resin and allowing the melt to solidify;
• followed by a potting step which involves the formation of end walls within the tubular housing by embedding the ends of the bundle in a potting resin;
• and a subsequent step which involves re-opening the fibers by cutting off the ends of the potted bundle together with part of the solidified potting resin after the potting resin has set and the end walls have been formed.