The present invention relates to a supporting net. More particularly, the present invention relates to a supporting net for a membrane in a dialysis device, ultrafiltration device, oxygenator or the like.
A number of constructions for a supporting net are known. For example, U.S. Pat. No. 3,962,095 discloses a membrane support material 14 best shown in FIGS. 3 and 4 of the patent. The membrane support 14 is described as bands of sheet material having on one side a series of spaced apart parallel ribs 16. The ribs 16 have a series of spaced grooves 18 which run substantially parallel to the membrane tube 12 as shown in FIG. 1 of the patent.
U.S. Pat. No. Re 27, 510 discloses a membrane support member best shown in FIGS. 6 and 7 of the patent. The support member 4 is comprised of parallel strands or wires 6 including an upper set of parallel strands 6u and a lower set of parallel strands 6y. When a membrane tube is disposed between two such supporting members as shown in FIG. 7 of the patent, section 2t of the membrane is forced between strands 6u to form therebetween elongated channels 20u and at the same time section 2s of the membrane is forced into plurality of channels 20y between strands 6y. The thickness of the strands, the distance between the strands and the angles between the upper set and lower set of strands are discussed at column 5, lines 52-57 of the patent.
Another such supporting device is disclosed in U.S. Pat. No. 3,963,621 as best seen in FIGS. 3, 4 and 5 of the patent. The membrane support 14 defines on one side thereof a first set of membrane supporting ribs 25 which are disposed longitudinally to the axis 28 of a tubular membrane 16. The first set of supporting ribs 25 define a plurality of rib sections 26 spaced by apertures 30 permitting the flow of fluid transversely across the membrane through ribs 25. The other side of the membrane support 14 defines a second set of ribs 33 which define an angle with the tubular membrane axis 28. The thickness of the membrane support and the height of, shape of and distance between the ribs is discussed in column 3, lines 35-41 of the patent.
Yet another such device is illustrated in U.S. Pat. No. 3,709,367 which discloses a supporting screen 12 best seen in FIGS. 2 and 4-6 of the patent. The supporting screen 12 is formed by a first plurality of strands 26 and a second plurality of strands 28 which are of like cross-section. The preferred cross-section is triangular in shape but other polygonal shapes are said to be suitable. The strands 26 are disposed in an upper pattern and the strands 28 in a lower pattern. Each pattern is supported by and underlies the other pattern. The strands in the upper pattern define an angle with respect to the strands of the lower pattern of less than substantially 90.degree.. The distance between the strands and the size, shape and composition of the strands is discussed in column 7, lines 6-57 in the patent.
Similarly, U.S. Pat. No. 3,743,098 discloses a support screen 20 comprising an extruded plastic netting having two sets of parallel strands lying against each other and defining an angle to each other. As shown in FIGS. 2 through 5 of the patent, the support screen defines a first set of strands 48 which run parallel to the longitudinal spiral axis 50 of a dialysis tube. A second set of strands 52 lies against strands 48, defining an angle with respect to strands 52. The distance between the strands and the thickness of the strands is discussed in the patent at column 3, lines 53-65.
In another similar device shown in U.S. Pat. No. 4,059,530, a web-like element is illustrated consisting of a first portion of a strip or sheet form 2a on which is superimposed a facing second portion of strip form 2b. Between portion 2a and portion 2b is placed a flattened tubular membrane 3. Each portion 2a and 2b comprises a base layer or web 4 which comprises uniformly distributed projections consisting of regular square-based pyramidal elements 5. The pyramidal elements are mutually spaced and aligned longitudinally and transversally so as to define spaces between them forming longitudinal grooves 6 and transverse grooves 7 disposed mutually perpendicular.
U.S. Pat. No. 3,880,760, U.S. Pat. No. 3,712,474, British Pat. No. 1,433,512 and British Pat. No. 1,417,446 likewise disclose supporting materials for dialysis membranes. These such supporting materials are, however, only described generally in these patents. For example, British Pat. No. 1,417,446 describes a supporting screen 3 which is a polyethylene screen of a generally known construction, while British Pat. No. 1,433, 512 describes a supporting gauze 3 of extruded polypropylene netting of a generally known structure. Similarly, the support material is shown in U.S. Pat. No. 3,880,760 as element 16 in FIG. 1 and in U.S. Pat. No. 3,712,474 as element 20 in FIGS. 4 and 7.