AU2001246242B2

AU2001246242B2 - Hollow fibre restraining system

Info

Publication number: AU2001246242B2
Application number: AU2001246242A
Authority: AU
Inventors: David John Cox; Fufang Zha
Original assignee: Evoqua Water Technologies LLC
Current assignee: Evoqua Water Technologies LLC
Priority date: 2000-04-10
Filing date: 2001-04-06
Publication date: 2005-03-03
Anticipated expiration: 2021-04-06

Description

1 HOLLOW FIBRE RESTRAINING SYSTEM O TECHNICAL FIELD

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The present invention relates to a restraining system for hollow fibres used in membrane filtration system.

BACKGROUND OF THE INVENTION A number of different types of restraining systems usually in the form of a welded plastic mesh cage have been used in the past, however, these suffer from lack of rigidity when large apertures are required in the mesh to allow for fluid flows and are difficult to repair should any portion of the mesh be broken during transport, installation or use.

While such known restraining systems are cheap and simple to manufacture they suffer from a lack of robustness in many required installations.

The present invention seeks to overcome or at least ameliorate one or more of the disadvantages of the prior art or at least provide the public with a useful alternative.

SUMMARY OF THE INVENTION According to the present invention, there is provided a filtration system, said filtration system comprising a bundle of hollow fibres and restraining system for the hollow fibres, said restraining system comprising a plurality of longitudinally extending elements spaced from one another and supported by a plurality of discrete spacer elements, said spacer elements extending generally transverse of said longitudinally extending elements, wherein said spacer elements and said longitudinally extending elements are arranged to define a cage like structure, wherein the longitudinally extending elements comprise rods and the spacer elements comprise rings, wherein each rod comprises a first width at a first location and a second width at a second location, wherein the first width is less than the second width, and wherein the rod engages with an associated spacer a the second location.

For preference, the cage-like structure is tubular.

In one preferred form, each ring comprises a plurality of radially extending engagement formations configured for releasably engaging an associated rod. The formations comprise part-circular opposed flanges spaced to provide a socket having an interference-fit with the associated rod.

In another preferred form, each ring comprises a plurality of radially extending cut-outs spaced around a periphery of the ring, each cut-out configured to provide an interference-fit or snap-fit with an associated rod. Preferably, an internal surface of -2- (1 each ring is bevelled along each internal edge. For further preference, each ring 2 comprises a cushioning element, wherein the cushioning element is situated on the

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internal surface of the ring. Preferably, the cushioning extends past the length of the ring at both ends of the ring so as to overlap the internal edges of the ring.

Preferably, each of the spacer elements comprise a plurality of sub-elements configured to fix together in use.

ND Preferably, the cut-outs are equally-spaced around the periphery of the ring.

For preference, each rod comprises a filtration system, said filtration system comprising a bundle of hollow fibres and restraining system for the hollow fibres, said restraining system comprising a plurality of longitudinally extending elements spaced from one another and supported by a plurality of discrete spacer elements said spacer elements extending generally transverse of said longitudinally extending elements, wherein said spacer elements and said longitudinally extending elements are arranged to define a cage like structure, wherein the longitudinally extending elements comprise rods and the spacer elements comprise rings, wherein each rod comprises a first width at a first location and a second width at a second location, wherein the first width is less than the second width, and wherein the rod engages with an associated spacer a the second location. Preferably, the second location comprises a circumferential groove or slot.

The components of the system are preferably formed of generally rigid plastics material, typically nylon and acrylonitrile butadiene styrene (ABS). The components can be moulded or machined to the desired configuration. The cut-outs preferably comprise a circular cross section and wherein the ring comprises an opening slightly smaller than a diameter of an associated rod to provide for snap-fitting retention of the associated rod.

Unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- -3c1 Figure 1 shows a perspective view of the restraining system according to one O embodiment of the invention;

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0Figure 2 shows a perspective view of the spacer component of the restraining system of Figure 1; Figure 3 shows an enlarged exploded perspective view of the restraining system of Figure 1; Figure 4 shows a perspective view of the restraining system according to a second N embodiment of the invention; O Figure 5 shows a perspective view of the snap ring component of the restraining N 10 system of Figure 4; WO 01/76727 PCT/AU01/00387 -4- Figure 6 shows a perspective view of the adaptor ring component of the restraining system of Figure 4; Figure 7 shows a perspective view of the restraining system according to a third embodiment; Figure 8 shows a perspective view of the snap ring component of the restraining system of Figure 7; Figure 9 shows a perspective view of the adaptor ring component of the restraining system of Figure 7; Figure 10 shows a perspective view of the restraining system according to a fourth embodiment; Figure 11 shows a perspective view of the snap ring component of the restraining system of Figure Figure 12 shows a perspective view of the adaptor ring component of the restraining system of Figure 10; and Figure 13 shows an enlarged perspective view of the end of the restraining system of Figure 4.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to Figures 1 to 3, the restraining system comprises a generally tubular cage-like structure 5 formed from a plurality of longitudinally extending rods 6 spaced from one another and held in position by a number of longitudinally spaced and transversely extending spacer rings 7.

WO 01/76727 PCT/AU01/00387 Each spacer ring 7 in this embodiment has a number of engagement sockets 8 spaced equally around its periphery. Each socket 8 is formed by partcircular opposed flanges 9 spaced to provide an interference or snap-fit with the associated rod 6. The sockets 8 are slightly over semi-circular in shape to provide retention of the rods 6.

Referring to Figures 4 to 13 of the drawings, each ring 7 in these embodiments has a number of radially extending cut-outs 10 equally spaced around its periphery, each cut-out 10 being sized and shaped to form an interference or snap-fit with an associated rod 6. The cut-outs 10 in this embodiment are slightly over semi-circular in shape to provide retention of the rods 6.

The rods 6 in this embodiment are provided with a circumferential groove or slot 11 to provide a reduced diameter/width at the location where they engage with the ring 7. This serves to prevent longitudinal movement of the rings 7 relative to the rods 6.

Each end of the tubular restraining structure 5 is provided with terminating adaptor ring 12 which, in use, mounts the structure 5 to a potting sleeve 16 or the like. The adaptor ring 12 includes a inner ring 13 having a plurality of openings 14 to allow passage of fluid therethrough and a radial extending circumferential rib 15. Rib 15 is again provided with a corresponding number of cut-outs 16 as those provided on the spacer rings 7 for engaging with the ends 17 of rods 6.

WO 01/76727 PCT/AU01/00387 -6- As shown in the various embodiments, the spacer rings 7 are preferably arranged in closely-spaced pairs. Further, the number of rods and rings can be varied according to restraint requirements. As best shown in Figure 10, the density of rod numbers can also be varied along the length of the tubular structure 5 where restraint requirements vary along the length.

The restraining system is used to restrain a bundle of hollow fibre membranes employed in filtration systems. The fibre bundle extends longitudinally within the tubular restraining system. The restraining system allows fluid flow to and from the hollow fibre membranes. Typically, the fibres extend between upper and lower headers which, together with the restraining system, can be used to form a replaceable fibre bundle module. In such arrangements, the cage has the added advantage of protecting the fibre bundle during deployment of the module.

It will be appreciated, that further embodiments and exemplifications of the invention are possible without departing from the spirit or scope of the invention described.

Claims

2. A filtration system according to claim 1 wherein the cage-like structure is tubular.
3. A filtration system accordingly to claim 1 or claim 2 wherein each ring comprises a plurality of radially extending engagement formations configured for releasably engaging an associated rod.
4. A filtration system according to any one of the preceding claims wherein the formations comprise part-circular opposed flanges spaced to provide a socket having an interference-fit or snap-fit with the associated rod.
5. A filtration system according to any one of the preceding claims wherein each ring comprises a plurality of radially extending cut-outs spaced around a periphery of the ring, each cut-out configured to provide an interference-fit or snap-fit with an associated rod.
6. A filtration system according to claim 5 wherein the cut-outs comprise a circular cross section and wherein the ring comprises an opening slightly smaller than a diameter of an associated rod to provide for snap-fitting retention of the associated rod.
7. A filtration system according to claim 5 wherein the cut-outs are equally-spaced around the periphery of the ring.
8. A filtration system according to any one of the preceding claims wherein the second location comprises a circumferential groove or slot.
9. A filtration system according to any one of the preceding claims wherein each of the spacer elements comprise a plurality of sub-elements configured to fix together in use. I -8- A filtration system according to any one of the preceding claims wherein an O internal surface of each ring is bevelled along each internal edge. O
11. A filtration system according to any one of the preceding claims wherein each ring comprises a cushioning element, wherein the cushioning element is situated on the internal surface of the ring.
12. A filtration system according to claim 11 wherein the cushioning element IND extends past the length of the ring at both ends of the ring so as to overlap the internal edges of the ring.
13. A filtration system substantially as hereinbefore described with reference to any 10 one of the embodiments of the invention illustrated in the accompanying drawings. DATED this 1 1 th day of October 2004 Shelston IP Attorneys for: U.S Filter Wastewater Group, Inc.