DE3050758

A hollow fiber separatory element of the type having a plurality of hollow semipermeable fibers terminating at their end portions in resin tubesheets; each tubesheet has a disc-shaped portion that tapers radially inwardly toward its inner end surface that serves as a pressure-induced sealing surface when forced into contact with a correspondingly tapered surface on the inner wall of a surrounding jacket. Each tubesheet optionally includes a second tapered portion that extends outwardly from the outer end face of the disc portion and its peripheral surface tapers radially inwardly toward the outer end planar surface which exposes the open ends of the fibers therein. The tubesheet disc portion may be circular, lenticular, elliptical or have other selected shape. The invention includes a hollow fiber medical separatory device which incorporates the new separatory element by a pressure type mechanical seal between the inner end surface of the disc portion of the tubesheet and a radially and axially inwardly extending tapering inner wall surface of the surrounding jacket of the device. The improved method relates to forming the new separatory element tubesheets by centrifugally casting a thermoplastic resin around the ends of the fibers in unique molds which enable uniform resin penetration and fiber wetting, and solidification of the molten cast resin into a sound and substantially void-free tubesheet having selected tapers.