NZ621627B2 - Method for controlling creep in spirally expandable profile - Google Patents

Abstract

elongated web or strip (200) comprising a wall portion bounded by edge portions and adapted to form a conduit by spirally winding said web and joining adjacent edge portions. The edge portions (210, 220) are adapted to permit relative movement between adjacent portions of the spiral conduit and thereby provide radial alteration of the conduit. The web includes a compensation portion (300) to alter the dimension of the web (200) upon radial alteration of the conduit and thereby compensate for creep in the spiral conduit. In a particularly preferred embodiment the edge portion comprises a primary lock (214, 224) and a secondary or sacrificial lock (212, 222). The sacrificial lock is disengaged by release of the mechanism 215 to permit relative movement there between and thereby effect radial alteration of the conduit. hereby provide radial alteration of the conduit. The web includes a compensation portion (300) to alter the dimension of the web (200) upon radial alteration of the conduit and thereby compensate for creep in the spiral conduit. In a particularly preferred embodiment the edge portion comprises a primary lock (214, 224) and a secondary or sacrificial lock (212, 222). The sacrificial lock is disengaged by release of the mechanism 215 to permit relative movement there between and thereby effect radial alteration of the conduit.

Description

- 1 _ Method for controlling creep in spirally expandable profile Technical Field The present invention relates to methods and apparatus for producing'spirally wound pipes or pipe liners, webs or profiles for such pipes and liners and in particular methods and apparatus for compensating creep in such spirally wound pipes or liners.

Background Art Any discussion of the prior art throughout the cation should in no way be considered as an admission that stich prior artis widely known or forms part of common general knowledge in the field.

There are various well known and conventional methods for repairing pipes, in particular underground pipes. The most labour intensive is of course a complete replacement or repair of the pipe's concrete/cement lining.

In recent years, new mechanisms have developed for providing a plastic al liner for the damaged pipe. This permits the damaged pipe to remain in place during and after repair, limits excavation and providesa rapid and relatively inexpensive repair.

One particular technique, and which is t of several Australian and overseas ~ s, involves lining a damaged pipe with a helically wound pipe formed from a extruded plastic web (sometimes referred to as a “profile”) with interlocking edges. In one such form-the pipe liner is installed as shown in Figure 1.: A winding machine 10 is lowered into the ‘ maintenance hole 20 and positioned at its base. A spool 40 of the profile 50 is provided at the surface. The profile 50 is fed to the winding machine 10 where it is helically wound into the pipe 30 in a d diameter form. lly, to rehabilitate a wastewater main with an internal diameter of 150 mm, a liner with an external er of 130 mm is used. This allows the pipe to be installed with minimal friction from one nance hole to the next, typically a distance‘of 50 to 100 .

As the profile 50 is wound into the pipe 30, the edges ofthe profile 50 are interconnected to form the liner. 60, but held such that relative movement between the adjacent edges of the respective profiles are prevented until the liner 60 can be ed to its final position. To explain, the liner 60 is initially inserted into the pipe 30 in a tightly wound form to permit easy ingress of the liner 60 into the pipe 30. As the spool 40 of the profile 50 is unwound, the resultant liner60 continues to progress along the pipe until it reaches the end of the pipe at the next maintenance hole. At this point the end of the liner 60 is held or fixed. The liner 60 is then _2_. ' expanded as discussed below such that its outer e contacts the inner surface of the pipe 30, thereby lining and sealing the pipe 30._ - In a currently available embodiment shown in Figure 2, the adjacent edges of the respective profiles which produce the spirally wound liner are held together by locking members 70, 80.. The g members 70 and 80 are provided by ribs 71, 81 on one respective profile, and channels 72, 82 on the directly adjacent profile to accept ribs 71, 81 and thereby hold the 1 wound profile in a spiral configuration. A wire 90 is positioned betWeen the locking members.

This wire is then removed from the liner 60 by pulling it radially inward through an opening 91 between the s to thereby sever one of the cannecting members .70 imes called a “sacrificial lock") and permit relative movement between the nt profiles and expansion of ‘ the liner to the final sed diameter. ably,‘the sacrificial lock 70 includes an adhesive to hold the liner, andprimary lock 80 includes a lubricant to allow relative movement between the adjacent edges of the profile u’pon severing of the sacrificial lock 70.

A problem may arise, however,in that the longitudinal or axial length of the liner 60 will reduce as the diameter is increased. To explain, as shown in Figures3A and 3B, upon release and radial expansion, the liner 60 will go from heliit angle or to helix angle [3‘ upon expansion.

This change in angle brings the profile cloSer to a right angle to the longitudinal axis. In turn this will necessarily reduce the length of the pipe from A to B. This reduction in length, sometimes referred to as "creep", may be of sufficient strength to force the winding machine 10 in direction 150 i.e. towards the pipe being repaired, potentially to contact the pipe or face 100 of the maintenance‘hole. If sufficient nce is not allovVed between the winding machine 10 and the face 100 of the nance hole 20, it is possible that this creep force 150 will cause the winding machine to come into contact with the wall of the maintenance hole and, since at this point further movement is not le, theinterlocking edges of the profile may separate and the liner 60 may fail. This will result in the liner 60 having to be completely removed from the pipe 30 Such a failed lineris of no further use, and cannot be talled. .

An appropriate clearance between the winding machine 10 and the maintenance hole 20 is difficult to estimate and, usually, it is necessary to remove at least some of the concrete structure in the nance hole. This of course requires operator time in the initial installation - - but also to reinstate the maintenance hole after lation.

The occurrence of creep is quite a complex subject. For each pipe that is spirally wound, as mentioned above, a helix angle is created that is determined by the pitch of the interlocking Received 02/07/2013 edges ofthe profile, the diameter at which the pipe is wound, and the width ofthe profile used. As the diameter of the pipe is increased upon expansion, for the same profile width7 the helix angle comes closer to an right angle to the axis of the pipe and effectively reduces the length ofthe pipe. During the expansion process, one end ofthe helically wound pipe liner is fixed and cannot move. The other end ofthe pipe is in the winding machine and is free to move within the clearance zone created during the initial section ofprofile setup. As the creep force is created during the expansion process, each needs to move to allow for the new helix angle. In effect, the entire section of the pipe cts in .

Another explanation is the small change in look pitching.

, Referring again to Figure 2, when the profile is initially wound, the position of locking member 70 mes referred to as a ficial loc ", determines the relative position of the engaging locks 70, 80. When the sacrificial lock 70 is disengaged by the wire 90, a new l position is created by the winding forces and the winding tension inside the pipe.

It is an object ofthe present invention to overcome or ameliorate at least one of the disadvantages ofthe prior art, or to provide a usefiil alternative.

It is an intention of at least the preferred embodiments of the present application to reduce and preferably ate aforementioned "creep" when installing spirally wound expanded pipes.

The term "creep" as used herein refers to force, either tension or cornpression primarily in the axial direction resulting from radial alteration, eg. expansion or contraction ofa spirally wound pipe, pipe liner, or cover.

DESCRIPTION OF THE INVENTION In a first aspect, the t invention provides an elongated web or strip comprising a wall portion bounded by edge portions and adapted to form a conduit by spirally g said web and joining adjacent edge portions, said edge portions including a primary locking formation and a secondary or sacrificial locking formation being adapted to permit relative nt of nt edge portions of said Spiral conduit to y provide radial alteration of said conduit upon severing or disengagement of said secondary/sacrificial lock formation, said Web further comprising a compensation n to alter the ions ofsaid web upon radial alteration of said conduit and thereby compensate for creep (as hereinbefore defined) in said spiral conduit, said compensation portion being provided at or directly adjacent one of said AMENDED SHEET lPEA/AU Received 02/07/2013 edge portions such that apart fiom the joint between adjacent webs, the interior surface ofthe web is substantially smooth and free ofdislocations.

In a second aspect, the present invention provides a method as claimed in the the said compensation portion alters the first aspect wherein upon application of creep, ions of said web in a substantially identical fashiorr around the circumference of said conduit.

In a third aspect, the present invention provides a method as claimed in the second aspect wherein said compensation portion is selectively engageable such that it remains vated during Spiral winding of said web and is activated upon expansion or contraction ofsaid conduit.

The present invention also provides a conduit, pipe liner or pipe cover comprising the aforementioned elongated web or strip.

It will be clear to the skilled addressee, and from the description below, that the aforementioned method and apparatus to reduce creep, es among other benefits, sed installation success rate, reduction in setup time to prepare a maintenance hole, reduce time to ate or repair a maintenance hole. It is also unnecessary to have highly skilled operators/installers since the aforementioned method and tus will not make it necessary for precise installation/clearance of the winding machine in the nance hole.

It should also be recognised that creep used hout the specification refers to longitudinal forces applied by a spirally wound pipe or pipe liner either in compression or in tension.

Unless the t clearly requires ise, 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 Embodiments ofthe present invention will now be described, by way of example only without tion, with reference to the anying drawings in which: Figure l is a diagrammatic View of a conventional installation system for spirally Wound pipes, Figure 2 is a close up view of a conventional connection system for connecting pro files or webs to form the spirally wound pipe, AMENDED SHEET IPEA/AU PCT/AUZO] 2/000920 Received 02/07/2013 Figure 3A and 3B are diagrammatic views of a spirally wound pipe or pipe liner/cover demonstrating the efl'ect of “creep” when the pipe is expanded, of adjacent webs Figure 4 is a cross-sectional View or profile ofthe edge p0rtion connected in ance with the present invention, AMENDED SHEET [PEA/AU Figure 5 is a close up view of the ted edge portions of the web incorporating the present ion, Figures 6A—6D are profiles of various embodiments of a web according to the present invention, Figure 7 is a cross-sectional" or profile view of a series of connected webs in accordance with yet a further embodiment of the present invention,'and Figures 8A-SE are various cross-sectional views of a further embodiment of a web according to the present invention. ' (J: BEST MODE(S) FOR CARRYING OUT THE INVENTION The present invention seeks to eliminate or at least reduce creep arising from installation of spirally wound pipes. In the embodiments shown, the pipe can' be produced from any lmaterial such as PVC plastic or similar. In some instances metal, eg. stainless steel, can be. used. 'It should be understood that the web or profile, and method ing to the present invention can be produced from any material provided it is suitable to be spirally wound to form' a pipe, pipe liner or cover”.

Turning firstly to Figures 4 and 5, the present invention provides an ted web 200' As will be clear to . whichis adapted to be spirally woundto form a pipe or pipe-liner/cover. 4 and 5, the web comprises a ' person skilled'1n the art, and as shown by the profiles'1n Figures mutually engageable edge ns 210 and 220 On opposite side edges In this embodiment ' ' one engagement n 210 provides two ding ribs 212, 214. The opposite edge portion 220 provides two mutually engageable recesses or channels 222, 224. As discussed above, and as well known in the an. a pipe or pipe liner/cover can be obtained by spirally windingsaid web. such that adjacent edge portions 210i 220 of adjacent webs are connected, This continuing spiral of the web 200 then forms the aforementioned pipe or pipe cover. ‘ The web 200 shown in Figures 4 and 5 is intended to be used as a pipe liner. In the ' embodiment shown, the inner side of the web 200 is essentially smooth with the outer side comprising strengthening or spacer s 230. The strengthening or. spacer s 230 of these members, . may assist in sliding the pipe liner into the damaged pipe. The size and shape however, are based on the strength and spacing requirements of the pipe or pipe liner. Ifthe profile 200 is sed as a pipe or pipe cover: members 230 may be regarded as strengthening s. If,‘however, the web 200 is being used as a pipe liner, members 230 act as spacers to space the internal. surface of the web 200 from the internal Surface of the pipe being repaired. will also be d that the aforementioned T—shaped s 230 may be sized to prevent any damage to the aforementioned engageable portions 0 or compensation portion 300 as they slide in the pipe .

It will be understood that the present invention is le for production of stand alone pipes,_ pipe liners and, even pipe covers. In the case of pipes and pipe liners, creep mayiarise ‘- - , after radial expansion of the pipeas discussed above. Similarly, creep forces may occur if .3 pipe cover is formed and, for example, reduced in diameter from its original position so that is forms closely over a damaged pipe. The arrangement of the present invention and its ability to compensate for the aforementioned creep is, applicable in both tension and compression.

Turning now to Figure 5, amore detailed view of the web profile is shown illustrating how the adjacent edge portions of the web are engaged. In detail, engagement ribs 210 are provided as a primary locking member 214 andsecondary or sacrificial locking member 212. A mentioned above, normally a wire or similar release member 215 is ed between the primary and sacrificial lock members. This wire or similar release member is removed from its on in between the locking members 212/214 thereby piercing or cutting sacrificial lock 212 and escaping through the spiral seam 250 where the webs 200 t each other: Once such a wire is removed and sacrificial lock 212 is severed, the pipe liner, as is well known in the art, expands until Spacer members 230 contact the inner surface of the pipe being repaired. This expansion brings the pipe liner ' to its final installed on. The expansion can occur immediately or in some cases progressively along the pipe liner. Expansion mechanisms may be provided internally of the pipe liner to assist in the ion process.

As mentioned above, however, it is this radial expansion of the pipe liner which reduces the overall axial length thereby leading to “creep". In the ment shown, a sation portion or expansion loop 300 is provided on web 200. When sacrificial lock member 212 is then cut and then radial expansion begins, the'compensation portion or expansion loop 300 similarly s or in this case‘lengthens in the udinal or axial direction to assist in compensating for the longitudinal change in length. While the aforementioned compensation portion/expansion loop 300 does not seem particularly large. it must be remember that this expansion loop 300 will Spiral around the length of the pipe 200 mimicking the path of the web 200 itself. It is expected that each such compensation portion 300 would expand by 0.5 to 1.0 .. mm r greater or small distances are within the scope of the invention. The overall effect of such compensation portion/ex‘pansion loop is quite significant.

If desired, the compensation portion 300 can be produced in any format, configuration or material desired. The compensation portion can be formed integrally with the web 200 as shown in Figures 4' and 5,. it can be an additional portion ed to the web 200 or can indeed be an additional component, e.g. intermediate web, as shown below in. Figure 7. The compensation portion can be co-extruded with the web or attached, e.g. by laser welding etc. 'In' the embodiment shown, the compensation portion acts to compensate primarily in the longitudinally axial direction. It eculd be envisaged that the sation portion may also act in the circumferential or radial direction to assist in reduction or elimination of creep resulting from radial expansion or contraction of the pipe liner as discussed above.

In the embodiment shown in Figures 4 and 5_ the compensation portion/expansion loop _ 300 is only engaged when radial expansion of the pipe liner 200 takes place. In other words, when the wire 215 severs sacrificial lock 2-12 and radial expansion of the pipe liner 200 begins, it is only then that the sation portion/expansion loop 300 is activated. If the wire 215 is not removed. such that the distance between rating engagement ls 222 and 224 remains the same, the compensation portion/expansion loop 300 would remain in it‘s relaxed state. In other words, the aforementioned compensation portion/expansion loop 300 in no way s installation or use of the pipe liner 300. It is only activated upon radial expansion 6f the pipe liner which in turn causes the entioned “creep”.

Turning to Figures 6A-6D various other embodiments of a compensationportion can be seen. In each of the web profiles shown in Figures 6A to GB, the compensation portion is provided n the adjacent edge portions of the web rather than at the adjacent edge portions as .ShOWn in Figure 4 and 5.

Figure 6A provides a single ion loop 410 approximately midway between the adjacent edge portions of the web as the compensation portion. '6B provides multiple expansion loops 420 along the web inbetween the aforementioned spacer members. Figure 6C provides an alternative embodiment'in which the strengthening/spacer members themselves are »'bifurcated to form opening 430 lcompensates for the longitudinal force being applied a result of the aforementioned “creepl‘ in the pipe liner.

Figure 6D es yet a further embodiment in which some of the spacer/reinforcing members are replaced with loop members 440. , The embodiment shown in Figures 4 and 5 is preferred for a number of reasons over the embodiments shown in 6A-'6D. the embodiment shown in is net . Firstly, Figures 4 and 5 activated until d. Further, the interior smooth surface of the pipe liner s smooth. It will be seen in figures 6A—6D that the internal side of the web 200, and as a result the internal face of the pipe liner, has a series of gaps or channels formed therein by the compensation portion or expansion loop. It should be stressed, however, thatIn each of the embodiments shown, the web is designed to ‘oompensate for any creep g from radial expansion or contraction of the spiral pipes/pipe liner.

Preferably, the inventive ement provides a compensation portion which is thevweb configured under load to provide substantial identical alteration of the dimensions of 'around the circumference of the conduit, To explain, some conventional web profiles have le portions adapted to provide flexibility to the resultant spirally wound pipe so that the pipe may be fed through bends. The t inventive arrangement, however, preferably, provides a compensation portion adapted to provide substantially identical alteration of the dimensions of the web. In othin' words-unlike a flexible spirally wound pipe where-one side would be in ssion and the other side in tension as it forms a bend, the present inventive method and tus e consistent, substantial identical extension (or in some cases . ssion) across or around the circumference of the conduit. In this fashion, the web profile and method provided by the present invention is clearly. and significantly different from conventional systems.

Still a further embodiment is provided in Figure 7. In this embodiment, an intermediate web 500 is provided. As seen in profile. the web 500 has edged portions cal to the primary web 200 such that it can be oned intermediate the flutes of the primary web 200 and still form a ly wound pipe/pipe liner"in a conventional fashion However, the intermediate web" 500 comprises a sation n similar to the aforementioned embodiments'1n Figures 4 and 6A~6D to reduce creep resulting fl'om radial expansion or contraction of the resultant . spirally wound pipe/pipe liner.

It should be ised here that this embodiment is particularly useful as it can be designed to suit a conventional spiral web or profile. This permits conventional web or profile to the used in conjunction with the present invention. In other words it does not render t stock obsolete. Rather it provides a mechanism for modifying the conventional profile/web while still compensating or alleviating creep.

It should also be mentioned that in the embodiments shown, the relevant compensation portions/expansion loop can be constructed from the same material as the web or. from a flexible compressable material. This is particularly true for the embodirnent shown in Figure 7. Indeed the intermediate web 500 could be entirely, ucted from a resilient al with the remaining conventional web 200 being produced from conventional substantially rigid material.

Figures 8A-B show various aspects of another particularly preferred embodiment of the present invention. The profile is shown as a separate element or web in Figure 8A and connected to adjacent profiles, in Figure 88.

In much the same way as the embodiments shown in Figure 4 and 5, the web 609 has mutually engageable edge portion610 and 620 on te side edges. One engagement portion 610 has upstanding rib 612 and 614. The opposite edge portion 620 'has mutually engageable recesses or channels 622 and 624. As shown more clearly in Figures 88 and 8D upstanding ribs 612 and 614 engage With and are held, at least initially, by the respective recesses or channels , 622 and 624.

In this instance, the sation portion 700 is provided directly nt the mutually ' engaged edge ns. As discussed above, these mutuallyengaged portions provided a primary lock 622/612 and _a ary or sacrificial lock 624/614. In this particularly preferred embodiment the sation portion 700 is provided ly adjacent these locks .and in particular the sacrificial lock rather than in between them as shown in Figures 4 and 5. This has a number of advantages in particular the compensation portion 700 does not cause interruption of fluid flow and, like the embodiments of Figures 4 and 5, maintains a ntially smooth inner surface of the pipe wall.

Use of the aforementioned webs of.profiles would be similar to conventional installation techniques. The web would be fed to a winding e and passed into the pipe to-be repaired.

In line with conventional mechanisms, the primary and sacrificial locks are engaged.’ The sacrificial lock may contain an ve to hold the pipe to, be wound at a fixed diameter. _.

During the installation s, the wire in inserted between the primary and sacrificial locks. A lubricant maybe provided in‘ the primary lock to permit relative nt n adjacent edges of the profiles.

After full installation of the pipe liner at the aforementioned reduced diameter, the wire is gradually used to sever to sacrificial lock so that the pipe liner expansion process can begin.

This process occurs as more profile is feed into the winding machine causing the diameter in the section where the lock is severed to increase. The end of the pipe remote from the machine is expanded first to the size of damaged pipe diameter. This continues along the pipe until finally reaching the winding machine. During this expansion process, the compensation portion within the web stretches slightly to absorb the creep force and allow the winding machine to remain with the same on y reducing the possibility of contact of the winding ne in the maintenance hole and damage to the e, hole or the spirally wound pipe liner The present invention is a significant advance over conventional spirally wound pipes and pipe liners. It not only providesa more robust and reliable pipe/lining system, installation is eased, there being no need to determine clearances or in any other fashion taking into account the potential difficulties associated with creep.

The person skilled in the art will understand that the inventive method and apparatus may be embodied in forms other than that specifically described herein without departing from the spirit or scope of the present invention.

PCT/AUZO] 21000920 Received 02/07/2013 FOLLOWS: THE

Claims (7)

CLAIMS DEFINING THE INVENTION ARE AS

1. An elongated web or strip comprising a wall portion bounded by edge portions and joining nt edge and adapted to form a conduit by spirally winding said web and a secondary or portions, said edge portions including a primary locking formation cial g formation being d to permit relative movement of adjacent edge of said conduit upon portions of said spiral conduit to thereby e radial alteration said web further ng or disengagement ofsaid secondary/sacrificial lock formation, cornprising a compensation n to alter the dimensions of said web upon radial 10 alteration of said conduit and y compensate for creep (as hereinbefore defined) said Spiral conduit, said compensation portion being provided at or directly adjacent one the interior of said edge portions such that apart from the joint between adjacent webs, surface ofthe web is substantially smooth and free ofdislocations. web is

2. A web or strip as claimed in any one ofthe preceding claims wherein said said compensation portion provides 15 configured such that upon application of creep, substantially identical alteration ofthe ions ofsaid web around the circumference ofsaid conduit.

3. A web or strip as claimed in any one of the preceding claims wherein said compensation portion alters the width of said web upon radial alteration of said conduit. 20

4. A web or strip as claimed in any one of the preceding claims wherein said web includes a selectively engageable mechanism to effect said radial alteration.

5. A web or strip as claimed in claim 4 wherein said selectively engageable mechanism co-operates with said sation portion such that said compensation portion is only activated upon said radial alteration. 25

6. A web or strip as claimed in any one of the preceding claims wherein said compensation portion is provided by a resilient material formed in said web.

7. A web or strip as claimed in any one of the preceding claims n said compensation portion is provided by an expandable formation in said web. AMENDED SHEET H’EA/AU Received