Abstract: A dialyzer is formed by first placing a film strip into a membrane hose and then simultaneously folding the hose and a netting intermediate layer so that the folds of the hose and the folds of the netting extend crosswise relative to each other in a mutually interlocking manner. The facing ends of the hose layers are then sealed with a curable sealing compound and severed. Then the film strips are withdrawn from the hoses in the so formed package. The resulting product is a dialyzer or hemofilter, depending on the type of membrane hose used, in which the facing ends of the membrane hoses are open for the passage of blood therethrough, after the withdrawal of the film, and in which the netting layers are located between adjacent hoses.

Abstract: The present blood exchange apparatus comprises a plurality of main layers acked to form a package. Each main layer includes a membrane envelope enclosing an intermediate netting layer. Spacers space the main layers so that blood may flow between adjacent main layers and an exchange liquid may flow within the intermediate netting layers. The facing ends of a package are embedded in a pourable sealing compound in such a manner that the spaces between adjacent membrane envelopes are open. After securing the spacers to each facing end of the main layers, the spacers and thus the layers are connected and then dipped into a curable sealing compound. The spacers have corner extensions which extend out of the sealing compound. Holes in the corner extensions expose the intermediate netting layers.