Abstract: The invention relates to a blood dialyzing apparatus comprising at least one bundle of semi-permeable hollow filaments and a cylindrical housing positioning said bundle of filaments and having a large length to inside diameter ratio of 7 to 10.

Abstract: Leaks from a hollow fiber membrane module comprising a housing having one or more hollow fiber bundles positioned therein with at least one end of each bundle being sealed by a cementing layer includes the step of applying a pressurized gas to the external surfaces of the hollow fibers. The gas which is used must have a refractive index different from the refractive index of the ambient atmosphere. The atmospheric volume adjacent the sealed end of the module is optically monitored for refraction patterns caused by gas leaking through the sealed end into the volume. The optical system includes a light source and components for directing light from the source along an optical path including the monitored volume. Light which is passed through the monitored volume is directed to an optical display where the refraction patterns of the leaking gas will be visible. The method and apparatus permit leaks to be located without the use of liquids.

Abstract: Semi-permeable membranes of regenerated cellulose are subjected to wet-heat sterilization at a temperature of 105.degree. to 140.degree. C. During the treatment, the membranes are maintained in contact with an aqueous medium such as water or physiological saline. For the dialysis of body fluids, hollow fiber, semi-permeable membranes so sterilized exhibit a sonic modulus of at least 6.5.times.10.sup.10 dynes/cm.sup.2. Hollow fibers made of cuprammonium regenerated cellulose are particularly preferred for the above purpose.

Abstract: A polyvinyl alcohol semi-permeable membrane is prepared which has micropores with an average diameter of 0.02 to 2 microns as defined by the interpore partition walls having thicknesses in the range of 50 to 5000 A and which is characterized by substantial cross-sectional uniformity. The membrane is prepared by extruding a PVA composition containing PAG with a molecular weight of 400 to 4,000 and a carbon-to-oxygen ratio of not more than 3 in a proportion of 2 to 200 parts by weight per 100 parts of PVA into a coagulation bath. In another embodiment of the invention, the membrane is formed from a PVA composition wherein the PAG has a molecular weight of 600 to 3,000 and a C/O ratio of not more than 3, the proportion of the PAG being 15 to 150 parts by weight per 100 parts of PVA and wherein the composition satisfies the relation: 0.65 .ltoreq. CBR (critical blending ratio) .ltoreq. 1.0. The membrane is useful in ultrafiltration, dialytic and osmotic separation applications.