Abstract: A hollow fiber medical separatory device of the type including a shell containing a plurality of hollow semipermeable fibers extending through a central dialysate chamber and terminating in spaced apart blood chambers; the device is improved by tubesheets at each end of the fibers having the shape of a frustum of a cone and sized such that the fibers fill the cone to the peripheral edge at the outer end planar surface of the frustum; and a multi-functional blood chamber means forming a blood chamber by pressure sealing engagement with the outer tapered surface of the cone and also pressure sealed to the outer end surface of the shell to prevent air ingress into the dialysate chamber during testing or use.The invention also includes a method for potting the frusto-conical tubesheets on the end portions of the fibers while the fibers are positioned in the shell which is improved by the use of steps and means to insure centering of the fibers in the cone during centrifugal casting of the resin.

Abstract: 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.