PIPELINE REPAIR APPARATUS INCLUDING EXPANDABLE FORMS

Abstract: Apparatus is disclosed for the in situ repair of an inner wall of a conduit or pipe by pressing a repair material in the form of a sheet or sleeve (24) with settable repair substance against a repair zone (12) of the conduit or pipe, the apparatus having a central tube (17) allowing liquid flow therethrough during a repair operation, an inflation zone (20) surrounding the tube (17) defined by a flexible inelastic material tube (19) sealed at opposed ends to the central tube (17), said flexible inelastic material tube forms a control means to prevent radial expansion beyond a predetermined limit and generally has an inflated diameter approximating the diameter of the conduit or pipe to be repaired, means (21) for introducing an inflation medium into said inflation zone (20), and elastic band means (25) surrounding the flexible inelastic material tube (19) to contract same upon said inflation medium being withdrawn from the inflation zone (20).

Description: PIPEUNE REPAIR APPARATUS INCLUDING EXPANDABLE FORMS The present invention relates to apparatus used in the process of refurbishing damaged conduits, pipelines and sewer pipes through the application of a reinforced lining to their inner walls by means of an inflatable form. The present invention is particularly but not exclusively intended for use in the repair of underground pipelines in situ to avoid the necessity of excavating the pipeline or re-routing flow from the pipeline around the repair site. Conventionally, two principal methods have been used for the refurbishment of cracked, broken or eroded pipelines or sewer pipes through so-called soft lining methods involving the application of a reinforced lining to their inner walls. One of these methods involves the eversion of a tube of thermosetting resin-impregnated reinforcement fabric into a section of pipe to be relined from an external position by means of a head of water. An example of this method can be seen in U.S. Patent No. 4,581 ,085. This method has the disadvantage that the pipe being repaired is necessarily blocked by the repair materials during the repair process and as a result, flow through the pipeline must be re-routed around the repair zone. A second method used involves carrying a layer of resin impregnated reinforcing material on an inflatable form to the repair zone within the pipe and thereafter inflating the inflatable form to press and hold the repair layer against the section of the pipe requiring repair for a length of time sufficient to allow the resins to cure. Examples of this type of repair can be seen in G.B. Patent No. 2136912, European Patent No. 370193 and Swiss Patent No. 635181. A short coming of these known systems is that the inflatable forms used essentially fully block the pipe during the repair process thereby interrupting all flow in the pipeline. Bypassing of the section being refurbished or some other means of stopping flow in the pipeline being repaired is therefore a necessity. A third form of pipeline repair is also shown in prior art specification but this type of process is not intended to refurbish a length of pipeline but rather is intended to repair localised defects, commonly cracks or gaps between discrete section lengths of a pipeline. In this type of repair process a settable liquid or semi-liquid sealant is pumped or forced into a zone between two axially spaced inflated parts pressed against the inner wall of the pipeline. Examples of this type of device are shown in U.S. Patent Nos. 3,9058,607, 4,763,51 1 , 3,618,639, 3,762,446, 3,834,421 , 3,958,607, 3,946,761 and G.B. Patent No. 2169983. These prior art references do not permit refurbishment of a length of pipe as the repair material cannot include a resurfacing material and cannot reliably extend over any length of an inner surface of a pipe as opposed to a crack or gap between pipe section lengths. In German Patent Application No. DE 3922351 it has been proposed to provide an annular form with an inflatable envelope on its outer surface such that flow within the pipeline being repaired may continue through the annular form while the repair process is being carried out. This avoids the problem discussed above relating to re-routing or stopping flow in the pipeline being repaired, however certain difficulties still exist. The form disclosed is essentially rigid making it extremely difficulty to get the form into an underground repair position from an above ground location when the form length is above a certain predetermined length. That is, above a certain length it is difficult or impossible to manoeuvre a rigid form within the confines of a manhole or access pit. Australian Patent Application No. 54471/90 discloses an arrangement wherein the inflatable form is formed by a plurality of individually rigid annular segments which are pressed together by cable tensioning means to form a rigid annular form when in use, the cable tensioning means being capable of being relaxed to allow the individual segments to be arranged at an angle to adjacent segments thereby facilitating introduction of the form into the pipeline from an above ground position or movement through a pipeline to the desired repair location. While this arrangement does not have the same problem as discussed above in relation to German Patent Specification No. DE 3922351 , it does have a problem in that it is complicated in construction and difficult to use where it is necessary to tighten the cable tensioning means underground at the repair location. While this can be achieved, it is an added complication in cost of producing the repair apparatus and in using the apparatus during a repair process. A still further problem with many prior art repair devices is that the inflation envelope or bag is commonly produced from a stretchable or expandable material such as rubber or rubber like material. In some situations a pipeline may be broken with a reasonably large washed out cavity in the earth around the break. Where this has occurred, it is possible for the pressure of an elastic inflatable form to displace a broken section, distend into the cavity and burst. If the repair is only partially cured it may, as result, be a failure and be impossible to remove without excavating the whole section of the pipeline. G.B. Patent Specification No. 2136912 discloses an inflatable form of the same general type as discussed above wherein the inflatable bag is produced from a non stretchable material such as nylon coated internally with Neoprene (for waterproofing). The diameter of this bag is selected to be generally equal to the diameter of the pipe being repaired less twice the thickness of the repair material. This G.B. patent does not, however, disclose any method of contacting the inflatable bag after the repair process has been completed to enable the repair device to be removed from the pipeline being repaired which is normally achieved by making the bag from an elastic material. The objective of the present invention is generally to provide repair apparatus and a method of operating such repair apparatus which will solve all or at least some of the difficulties associated with prior art devices as discussed above. In particular, in a first aspect, the present invention aims at providing repair apparatus which can be positioned as desired within a pipe to be repaired from an above ground position without significant complications in construction or use of the apparatus and without preventing normal flow in the pipeline being repaired while the repair process is carried out. In a second aspect, the present invention aims at providing apparatus which will prevent the inflatable form expanding into a cavity surrounding the repair zone beyond a predetermined limit thereby ensuring against the inflation material bursting with the possible consequent effect of the repair material and repair apparatus becoming irretrievably stuck at the repair site, while at the same time allowing contraction of the inflatable form upon completion of the repair process. According to said first aspect, the present invention provides apparatus for applying in situ a repair material in the form of a sleeve or sheet including a settable material to a repair zone of an inner wall of a conduit or pipeline, said apparatus comprising a core member having a radially expandable device located outwardly of said core member and extending axially along and at least partially circumferentialiy around said core member, said core member including a hollow flexible tube of a non perforate material and having a fixed axial length capable of transverse bending but adapted to resist inward deformation caused by internal pressure within said expandable device during εf repair operation. Conveniently, apparatus of the aforementioned kind comprises a pair of rigid end members interconnected by said hollow flexible tube, each of said end members having a central through flow opening communicating with the hollow interior of the hollow flexible tube. Preferably, the expandable device comprises a flexible sheet or tube connected at either end to the rigid members and defining at least in part, an enclosed space adapted to inflate under action of an applied pressure medium. In accordance with the aforementioned second aspect the present invention also provides apparatus for applying in situ a repair material to a repair zone of an inner wall of a conduit or pipeline, said repair material comprising a sheet or sleeve of predetermined dimensions including a settable repair substance, said apparatus comprising a radially expandable device arranged to carry said repair material to said repair zone and to press said repair material outwardly against the inner wall of said conduit or pipeline on either side of said repair zone, said expandable device including a flexible material forming an outer part of an expandable cavity, means being provided to allow a pressure medium to be directed into or withdrawn from said expandable cavity whereby, when the pressure medium is directed into said expandable cavity, the flexible material is moved radially outwardly, control means forming part of said radially expandable device to prevent said flexible material moving substantially in a radial direction beyond a predetermined limit and to radial contraction of said flexible material upon said pressure medium being withdrawn from said expandable cavity. In one preferred embodiment the flexible material is non-elastic forming the control means preventing radial expansion beyond a predetermined limit, said control means further including recovery means separate from said flexible material enabling said material to contract radially inwardly upon withdrawal of said pressure medium from said expandable cavity. In a second preferred embodiment, the flexible material is elastic and said control means comprises one or more non-elastic circumferentially extending members co¬ operating with said flexible material to prevent said flexible material moving substantially in a radial direction beyond said predetermined limit. By means of these simple arrangements, a pipe may be repaired in situ without danger of the inflatable member expanding into a cavity around the repair zone to a stage where bursting might occur." In accordance with this . spect, the present invention also provides a method applying in situ a repair material comprising a sleeve or sheet or including a settable material or substance to a repair zone within a pipe or conduit to be repaired, said method comprising: applying externally of said pipe or conduit to be repaired, said repair material to repair apparatus comprising a radially expandable device including a flexible material forming an outer part of an expandable cavity and means for directing a pressure medium to or withdrawing a pressure medium from said expandable cavity, said repair material being positioned radially outwardly of said radially expandable device; carrying said repair material on said repair apparatus into the pipe or conduit to be repaired and positioning said repair material adjacent said repair zone; introducing a pressure medium into said expandable cavity and thereby expanding said flexible material outwardly so as to press the repair material against an inner wall part of the pipe or conduit on either axial side of said repair zone, while restraining expansion of said flexible material so as to prevent expansion of said flexible material through the pipe or conduit being repaired at said repair zone beyond a predetermined limit; holding said pressure medium in said expandable cavity for a length of time sufficient to at least partially set said settable material; Withdrawing said pressure medium from said expandable cavity whereby recovery means contracts said material inwardly away from said repair material; and thereafter withdrawing said repair apparatus from said pipeline or conduit being repaired. Conveniently said flexible material is non-elastic and said recovery means comprises, one or more circumferentially extending elastic members co-operating with said non-elastic flexible material. Alternatively the flexible material may be formed from an elastic material and at least one circumferentially extending non-elastic member co-operating with said elastic flexible material is provided to prevent the expansion of said flexible material through the pipe or conduit being repaired at said repair zone beyond the predetermined limit. Consequently the flexible material has a fully inflated diameter between 100 and 150%, preferably about 110%, of the inner diameter of the pipeline after application of the repair material thereto. Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which : Figure 1 is a longitudinal cross-sectional view of a first embodiment of the present invention; Figure 2 is a longitudinal cross-sectional view of a second embodiment of the present invention; Figure 3 is a view sharing the embodiment of Figure 2 in a position of use; Figure 4a is a cross-sectional view along line A-A of Figure 2; Figure 4b is a partial section view of the end of the apparatus adjacent section A-A with the sheath member removed for the sake of clarity; Figure 5 is a cross-sectional view along line B-B of Figure 2; and Figure 6 is a cross-sectional view along line C-C of Figure 2; and Figure 7 is a view similar to Figure 6 except that the expandable cavity has been expanded. Referring first to Figure 1, the apparatus 10 is shown within a pipe 11 to be repaired having a repair zone 12. The apparatus 10 comprises a pair of longitudinal spaced end members 13, 14 which may be formed from solid metal or fabricated from sheet metal such as aluminium or an aluminium alloy. Each member 13, 14 has a longitudinal through flow passage 15 and connection means 16 to permit connection of cables 30 or the like (Figure 3) to allow positioning of the member within the pipe to be repaired. A flexible tube 17 interconnects the two end members 13, 14. The tube 17 is conveniently formed from a rubber or other elastomeric material and is reinforced so that deflections or deformations inwardly are resisted but the tube 17 is sufficiently flexible to allow transverse bending to allow the apparatus to be moved around bends in the pipe 11 to be repaired. Flexible cables or chains 18 are provided interconnecting the two end members 13, 14 to ensure that they do not separate under the loads required to winch same into position or to withdraw same after a repair process has been completed. The through flow passages 15 and the interior of the tube 17 provide a longitudinal passage that allows continued flow through the pipe 11 during positioning or withdrawal of the apparatus 10 and during the repair process itself. Radially outwardly of the tube 17 is a flexible and expandable tube 19 which is connected by any suitable means 26, 27 at either end to the end members 13, 14. The flexible and expandable tube 19 defines an expandable cavity 20 essentially between itself and the outer surface of the tube 17. Access is provided through one or more passage means 21 in at least one of the end members 13, 14 to allow introduction or withdrawal of a pressure medium (liquid or air - preferably heated) to the cavity 20 to thereby expand this cavity and move the tube 19 radially outwardly. If the tube 19 is elastic and therefore stretchable then upon withdrawing the pressure medium from the cavity 20, the tube will contract radially inwardly. Located radially outwardly from the tube 19 is a sheath member 22 which is connected at one end 23 to one of the end members 13. The sheath member 22 is provided to assist removal of the apparatus from the pipeline upon completion of a repair operation as is explained in Australian Patent Application No. 54771/90. The sheath member 22 may alternatively be constructed as a separate unit as disclosed in Australian Provisional Patent Application No. PL 1466 filed on the 20th March, 1992. The subject matters of these co-pending patent applications are included herein by this cross reference thereto. The sheath member 22 carries to the repair zone 12 (Figure 3), a repair material 24 in the form of a reinforcement impregnated with a settable material such as a thermosetting resin. Advantageously, the settable material will not readily set at normal temperatures but will set upon an elevated pressure medium (such as hot water) being introduced into the expandable cavity 20. Figure 2 illustrates in longitudinal cross-section an alternative embodiment to the apparatus shown in Figure 1. Like features in Figure 2 have been given the same reference numerals as in Figure 1 and are not further described hereafter. The essential difference between the two arrangements lies in the configuration of the member 19 forming the outer wall of the expanding cavity 20. In this case the wall is formed by a non-elastic non-stretchable flexible material which is capable of containing the pressure of the injection medium used. A knitted polyester fibre yarn coated with vinyl material to provide a seal has been found satisfactory. Other materials that are non- elastic under normal operating pressures, that are flexible, and that are capable of retaining the pressure medium during use, may equally be used. As can be seen in Figures 4a and 4b, the end of the tubular member 19 is wrapped about the end member 13 (or 14) and is sealed thereto with a suitable sealant and clamping bands 26. As a result, in the position where there is no pressure medium in the cavity 20 or insufficient medium to expand the cavity 20 (as illustrated schematically in Figure 2, 4b, 5 and 6), the material forming the wall 19 is folded in on itself to form a trough 27 and is maintained in this contracted position by a plurality of elastic bands 25 spaced along the full longitudinal length of the apparatus. The bands 25 may be secured to the tube 19 to axially locate same as desired. The bands 25, if suitably secured to the tube 19 could also be positioned inwardly of the tube 19. It will of course be appreciated that one long elastic sleeve could also be used in substitution for the elastic bands 25. When pressure medium is introduced through passage means 21 , the folds in the material forming the wall 19 move outwardly so that the wall as a whole moves radially outwardly to the position illustrated in Figures 3 and 7. However, as shown in Figure 7, there may remain some extra material as folds 28 in the tube 19 that is retained generally within the sheath 22 even when the zone 20 is operationally inflated. Thus, in abnormal circumstances, the tube 19 may still expand radially outwardly until all the material of the tube 19 is used in its circumference and at this stage no further outward movement is possible. The radial outward movement occurs against radially inward forces provided by the bands 25 which again contract the wall 19 when the pressure medium is removed from the cavity 20. The material of the wall 19, being essentially non-extensible itself, prevents the cavity 20 expanding to such a condition that wall 19 may distend into a washed out cavity around the repair zone of the pipe being repaired and, as a result, burst. In an alternative embodiment it may be possible to mould the material forming the tube 19 so that it has a greater diameter along its central longitudinal dimensions and a narrower diameter approximating the outer diameter of the end members 13, 14, at its ends. In a still further alternative embodiment it is possible to manufacture the flexible material tube 19 from an elastic material which is capable of stretching outwardly under pressure applied from within the expandable cavity 20. In this case it is preferred to provide one or more circumferentially extending members of a non- elastic material co-operating with the tube 19 having an inflated diameter generally corresponding to the maximum desired inflation diameter of the tube 19. These non- elastic circumferentially extending members may be in the form of a plurality of bands (similar to bands 25) or perhaps a single sleeve member. Advantageously the members would be secured at one or more circumferential locations to the tube 19 and if desired could be located inwardly or outwardly of the tube 19. In operation, both embodiments of Figure 1 and 2 are moved into position adjacent the repair zone 12 by apparatus not shown. The embodiment of Figure 2 is shown in Figure 3. in this position, the cavity 20 is expanded by introduction of a pressure medium so that the wall 19 moves radially outwardly to press the repair material 24 against the pipe wall 11 on opposed axial sides of the repair zone 12. In the case of the embodiment of Figures 2 and 3, the repair material is not extended into the cavity behind the repair zone beyond a certain limit as discussed above. If there is no deep cavity at the repair zone, the repair material might be pressed against the entire repair zone if desired. After the repair material is sufficiently set, the cavity 20 is deflated and the apparatus is removed by withdrawing in a direction such that the sheath member 22 will peel from the repair material by at least partial eversion. In the illustrated embodiments, the apparatus would be withdrawn by movement towards the right in Figure 1 , 2 and 3.

Claims: THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1 . Apparatus for applying in situ a repair material to a repair zone of an inner wait of a conduit or pipe line, said repair material comprising a sheet or sleeve of predetermined dimensions including a settable repair substance, said apparatus comprising a radially expandable device arranged to carry said repair material to said repair zone and to press said repair material outwardly against the inner wall of said conduit or pipeline on either side of said repair zone, said expandable device including a flexible material forming an outer part of an expandable cavity, means being provided to allow a pressure medium to be directed into or withdrawn from said expandable cavity whereby, when the pressure medium is directed into said expandable cavity, the flexible material is moved radially outwardly, control means forming part of said radially expandable device to prevent said flexible material moving substantially in a radial direction beyond a predetermined limit, and to radial contraction of said flexible material upon said pressure medium being withdrawn from said expandable cavity. 2. Apparatus according to claim 1 wherein said flexible material is non-elastic forming the control means preventing radial expansion beyond a predetermined limit,, said control means further including recovery means separate from said flexible material enabling said material to contract radially inwardly upon withdrawal of said pressure medium from said expandable cavity. 3. Apparatus according to claim 2 wherein said recovery means comprises at least one band located intermediate opposed axial ends of said radially expandable device, the or each said band directing an inwardly contracting force to said radially expandable device but being- expandable therewith upon said pressure medium being directed into said expandable cavity. 4. Apparatus according to claim 2 or claim 3 wherein an end member is located at opposed axial ends of said radially expandable device, said flexible non-elastic material being formed as a sleeve with each axial end of said sleeve being secured to a respective one of said end members whereby along at least a central portion of said radially expandable device said non-extensible material is folded in upon itself to form a trough in said sleeve when the pressure medium is withdrawn from said expandable cavity. 5. Apparatus according to claim 1 wherein said flexible material is elastic and said control means comprises one or more non-elastic circumferentially extending members co-operating with said flexible material to prevent said flexible material moving substantially in a radial direction beyond said predetermined limit. 6. Apparatus according to claim 5 wherein the or each said non-elastic circumferentially extending members are joined to said flexible material at at least one location. 7. Apparatus according to any one of claims 1 to 6 further including a core member about which said radially expandable device is located, said core member including a hollow flexible tube of fixed axial length capable of transverse bending but adapted to resist inward deformation caused by said pressure medium, said hollow flexible tube defining at least in part, a through flow passage extending between opposed axial ends of said apparatus whereby flow in the pipeline or conduit being repaired is not prevented during a repair process. 8. Apparatus according to claim 7 wherein said hollow flexible tube is a reinforced elastomeric or rubber tube. 9. Apparatus according to claim 4 wherein at least one elongate flexible restraining member is provided interconnecting said end members, the or each said restraining member preventing said end members from moving axially apart beyond a predetermined limit. 10. Apparatus according to any one of claims 1 to 9 wherein a flexible sleeve member is provided outwardly of said radially expandable device adapted to be located between said radially expandable device and said repair material, said flexible sleeve member being connected to said apparatus only at or adjacent one axial end of the flexible sleeve member. 11. A method of applying in situ a repair material comprising a sleeve or sheet including a settable material or substitute to a repair zone within a pipe or conduit to be repaired, said method comprising : applying externally of said pipe or conduit to be repaired, a said repair material to repair apparatus comprising a radially expandable device including a flexible material forming an outer part of an expandable cavity and means for directing a pressure medium to or withdrawing a pressure medium from said expandable cavity, said repair material being positioned radially outwardly of said radially expandable device; carrying said repair material on said repair apparatus into the pipe or conduit to be repaired and positioning said repair material adjacent said repair zone; introducing a pressure medium into said expandable cavity and thereby expanding said flexible material outwardly so as to press the repair material against an inner wall part of the pipe or conduit on either axial side of said repair zone while restraining expansion of said flexible material so as to prevent expansion of said flexible material through the pipe or conduit being repaired at said repair zone beyond a predetermined limit; holding said pressure medium in said expandable cavity for a length of time sufficient to at least partially set said settable material; withdrawing said pressure medium from said expandable cavity whereby recovery means contracts said material inwardly away from said repair material; and thereafter withdrawing said repair apparatus from said pipeline or conduit being repaired. 12. A method according to claim 11 wherein said flexible material is non-elastic and said recovery means comprises one or more circumferentially extending elastic members co-operating with said non-elastic flexible material. 13. A method according to claim 11 wherein said flexible material is formed from an elastic material and at least one circumferentially extending non-elastic member co¬ operating. -with said elastic flexible material is provided to prevent the expansion of said flexible material through the pipe or conduit being repaired at said repair zone beyond the predetermined limit. 14. A method according to claim 12 or claim 13 wherein said flexible material has a fully inflated diameter between 100 and 150% of the inner diameter of the pipeline or conduit after the repair material has been applied thereto. 15. A method according to claim 14 wherein said flexible material has a fully inflated diameter of about 110% of the inner diameter of the pipeline or conduit after the repair material has been applied thereto. 16. Apparatus for applying in situ a repair material in the form of a sleeve or sheet including a settable material to a repair zone of an inner wall of a conduit or pipeline, said apparatus comprising a core member having a radially expandable device located outwardly of said core member and extending axially along and at least partially circumferentially around said core member, said core member including a hollow flexible tube of a non perforate material and having a fixed axial length capable of transverse bending but adapted to resist inward deformation caused by internal pressure within said expandable device during a repair operation.

Inventors: VOWELS ROBERT WALTER, VOWELS, ROBERT, WALTER
Applicants: BARRY BROS SPEC SERVICES, BARRY BROS. SPECIALISED SERVICES PTY. LTD.
Application year: 1993
Main classification: F16L55
IPC codes: F16L55