Embossed membrane support

#This invention relates to coil-type dialyzers or membrane diffusion devices of the type used in artificial kidney systems; and more particularly, to an embossed membrane support member for use in such devices.

#Coil dialyzers used in artifical kidney systems, such as the one disclosed in U.S. Pat. No. 3,743,098, include an elongated tubularly-shaped semipermeable membrane and a membrane support member which are wound together about a cylindrical core. Blood from a patient flows through the dialyzer inside the membrane and dialysis solution flows though the dialyzer in a crosswise direction. The dialysis solution flows between the windings of the membrane and support member so as to contact the membrane and receive bodily waste products from the blood.

#The membrane support disclosed in U.S. Pat. No. 3,743,098 is a foraminous screen. Recently, embossed support members have been developed which include an imperforate center who having equal-height support ribs on each side of the web. The ribs engage and position the membrane in the dialyzer, as well as define flow channels between the support member and membrane for the dialysis solution.

#FIG. 1 is an exploded, fragmentary, perspective view of a coil dialyzer showing the tubularly-shaped semipermeable membrane and the embossed support member, wound together about the cylindrical core;

#FIG. 2 is a greatly enlarged, fragmentary, cross-sectional view taken substantially along line 2--2 of FIG. 1 and showing in greater detail the manner in which the membrane is supported by the support member; and

#FIG. 3 is a greatly enlarged plan view of a portion of the skip rib side of the support member.

#Referring to the drawings, a membrane diffusion device or coil dialyzer 10 is shown for use in an artifical kidney. The dialyzer includes a cylindrical core 12, about which is wound an elongated, flexible support member 14 and a flat, expandable and tubularly-shaped semipermeable membrane 16. The support member and membrane are coiled together so that the membrane is both supported by and positioned in the dialyzer by the support member.

#The membrane 16 is made of cellophane or a cellulose derivative (such as sold under the trade name Cuprophan) and serves as the conduit for blood passing through the dialyzer. Cellophane membranes have the characteristic that when they are filled with fluid, they stretch approximately three times further in the transverse direction than in the longitudinal or blood flow direction.

#The inlet end 18 of the membrane is secured to the core 12, and an inlet tube 20 which carries blood from a patient, extends through the wall of the core and is connected at one end to the membrane inlet end 18. The outlet end (not shown) of the membrane is positioned radially outwardly of the core and is connected to an outlet tube (not shown) for directing treated blood back to the patient.