Patent GB-1208034-A (GB)
Title: Improvements in ultra-filtration apparatus
IPC: D01D10/04
Filed: 1968-05-17
Abstract: 1,208,034. Dialysis apparatus. AMERICAN STANDARD Inc. 17 May, 1968 [22 May, 1967], No. 23612/68. Heading B1X. A unit for "ultra-filtration", i.e. dialysis, apparatus comprises (1) a tubular ultra filtration member which consists of a porous support tube the interior of which is lined with an osmotic membrane, (2) a resilient tubular plug which is positioned inside the open mouth of one end of the tubular ultra-filtration member, and (3) a feed pipe which is positioned in a bore extending through the resilient tubular plug, at least one portion of the well of the plug having, in the free state of the plug before assembly of the ultra-filtration member, plug and feed pipe, an enhanced thickness which is greater than the width of the annular space existing between the ultra-filtration member and the feed pipe after assembly of the ultrafiltration member, plug and feed pipe so that, after such assembly, at least a portion of the plug is distorted and compressed in the annular space thereby to establish a liquid-tight seal between the ultra-filtration member and the feed pipe. As illustrated in Figures 1 and 2A, a resilient tubular plug 10 is positioned inside the mouth at one end of a porous support tube 12 the interior of which is lined with a tubular osmotic membrane 14. A feed pipe 16 is positioned in a bore 18 which extends axially through the plug and which has a tapered portion 22 at end 24 of the plug. In order to hold the osmotic membrane-lined support tube, plug and feed pipe in assembled sealing relationship, the plug is formed at end 20 thereof with an external flange 26 and the support tube has attached to the exterior at one end thereof a threaded collar 30 which cooperates with a threaded cap nut 32; when so assembled, an annular space 28 may exist between the internal wall of the bore of the plug at one end thereof and the feed pipe. The plug may be made of a compressible elastomer, for example rubber; a silcone rubber is preferred. The porous support tube may be made of a ceramic material or of woven glass fibre; the osmotic membrane may be in the form of a tubular film of cellulose acetate. Five other embodiments of plug are illustrated in Fig. 2B wherein the bore in plug 34 reduces in section via tapered portion 36 and wherein one end surface of the plug is formed with a V-shaped groove 37; in Figure 2C wherein plug 38 is formed with an external annular bead 40 and wherein the bore in the plug has a tapered portion; in Figure 2D wherein plug 42 is formed with two external annular beads 44 each of which may be in the form of a rubber O-ring separate from, rather than integral with, the plug; in Figure 2E wherein the interior wall of the bore extending through plug 46 is formed with at least one internal annular bead 48; and in Figure 2F wherein plug 50 itself is tapered and is formed with an axial bore of uniform cross-section. Figures 3 and 4 (not shown) illustrate ultrafiltration apparatus comprising a plurality of units modified in that each end of each tubular ultra-filtration member is provided with a resilient 'tubular plug and feed pipe, the ends of adjacent ultra-filtration members being connected together by means in the form of end manifold plate assemblies in which are formed channels to interconnect the ultra-filtration members in series. The apparatus may be used in for example the desalination of salt water, fresh water being collected from the exterior of the osmotic membrane-line support tube or tubes.