Abstract: A reciprocating dialyzer is described for use as an artificial kidney or other extracorporeal mass transfer device. A dialyzer unit includes a membrane package having an aligned pair of thin semi-permeable membranes forming a chamber between the interior faces to receive fluid (such as blood) to be treated, and spacing elements in dialyzate chambers at the exterior faces of the membranes which contact the membrances and limit their expansion, while allowing chemical transfer to the dialyzate slurry. A plurality of such treatment units received between spaced plates comprises a dialyzer. Blood flow into and out of the membrane packages is through a central conduit, with free slurry being introduced and withdrawn from the dialyzate chamber at the periphery of each unit.

Abstract: A small, portable, chemical reactor adapted to tap the venous blood supply of a patient, said device including a stack of semi-permeable membranes blood and dialysis materials in alternate chambers, said stack being held in sealed relationship by a single center bolt which facilitates quick assembly and disassembly.