PIPELINE REHABILITATION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent

Application Serial No. 61/139,835, filed on December 22, 2008, which is incorporated by reference herein for all purposes.

TECHNICAL FIELD

[0002] Embodiments of the present invention relate generally to rehabilitation of pipelines, and more specifically to grout injection and distribution in pipeline liner installation.

BACKGROUND

[0003] After time, pipelines often suffer from corrosion of the inner diameter and/or minor cracking and/or leakage. Such pipelines must often be replaced or rehabilitated. Replacement often involves the movement or destruction of above- ground structures, such as roadways or sidewalks. Rehabilitation, on the other hand, may permit a new inner diameter of the pipe to be created using the existing pipeline as an outer shell, which may eliminate the need to dig up large sections of existing pipeline and/or water mains, and which may involve significant cost savings over replacement.

[0004] One form of pipeline rehabilitation involves the installation of a tubular liner inside of a host pipe with hardenable cement mortar (formed from grout) between the tubular liner and the host pipe. However, grout injected between the tubular liner and the host pipe may have a tendency to slide off of the tubular liner and flow down below the tubular liner, thereby inhibiting ideal grout coverage in the uppermost areas between the tubular liner and the pipeline. Also, as the grout is distributed between the liner and the pipeline, entrained or entrapped air due to lack of adequate back pressure can cause defects or gaps in grout coverage.

SUMMARY

[0005] According to some embodiments, a back-pressure device (e.g. another swab) is inserted into the back end of the tubular liner, the back-pressure device having a core hole formed therethrough, the grout dam device configured to maintain a back pressure between the tubular liner and the pipeline. According to other embodiments, a back pressure swab is inserted into the front end of the pipeline, the back pressure swab having a core hole formed therethrough, and the tubular liner is positioned inside of or through the core hole. According to such embodiments, advancing the first swab through the tubular liner from the front end to the back end of the tubular liner includes pushing the back pressure swab ahead of the first swab from the front end to the back end of the pipeline. In addition to the injection of grout into the trough at the front end of the pipeline, grout may also be injected into one or more intermediate grout ports along the pipeline.

[0006] A method for pipeline rehabilitation according to embodiments of the present invention includes deploying a tubular liner along an inside of a pipeline, the tubular liner and the pipeline each having a front end and a back end; inserting a grout dam device into the pipeline, the grout dam device having an opening formed therethrough, the opening having an inner diameter that varies over at least a portion of the opening; placing the tubular liner through the annular opening; injecting grout into the pipeline between the tubular liner and the inside of the pipeline; and advancing a swab through the tubular liner from the front end to the back end of the tubular liner to distribute the grout between the tubular liner and the pipeline and to advance the grout dam device ahead of the swab in a direction from the front end to the back end of the pipeline. Advancing the swab through the tubular liner from the front end to the back end of the tubular liner may include applying a fluid, for example air and/or water, in the tubular liner behind the swab. According to embodiments of the present invention, a distance between the swab and the grout dam device decreases as the grout dam device advances ahead of the swab in the direction from the front end to the back end of the pipeline, due to an amount of the grout between the swab and the grout dam device decreasing as the grout is distributed between the tubular liner and the pipeline.

[0007] A system for rehabilitation of a pipeline according to embodiments of the present invention includes a tubular liner configured for deployment along an inside the pipeline, a grout dam device having a first end, a second end, and an opening extending from the first end to the second end, the opening configured to receive the tubular liner therethrough, the opening having an inner diameter that increases substantially linearly over at least a portion of the opening from the first end toward the second end, and a seal coupled to the grout dam device, the seal configured to substantially fill a space between the grout dam device and an inner circumference of the inside of the pipeline.

[0008] The grout dam device of any one of paragraphs [0005] through

[0016] may further include a limiter tube coupled to the grout dam device, wherein the opening extends through the limiter tube, and wherein the inner diameter of the opening is substantially constant along the limiter tube.

[0009] The grout dam device of any one of paragraphs [0005] through

[0008] may include a limiter tube that has a grout end and a device end, wherein the device end of the limiter tube is coupled to the grout dam device, wherein the grout end of the limiter tube is configured to extend from the first end of the grout pressure device and to limit a radial extent of the tubular liner exiting the grout end, and wherein the inner diameter of the opening increases substantially linearly from the device end of the limiter tube toward the second end of the grout dam device.

[0010] The system of any of paragraphs [0007] through [0009] may further include a swab.

[0011] The system of any of paragraphs [0007] through [0010] may further include the grout dam device, the tubular liner, and the swab being inside of the pipeline, wherein the tubular liner extends through the opening, and wherein the swab is inside of the tubular liner.

[0012] The system of any of paragraphs [0007] through [0011] may further include the grout dam device, the tubular liner, and the swab being inside of the pipeline, wherein the tubular liner extends through the opening, wherein the swab is inside of the tubular liner, and wherein the swab is closer to the first end of the grout dam device than to the second end of the grout dam device.

[0013] A system for rehabilitation of a pipeline according to embodiments of the present invention may include a grout dam device having a first end, a second end, and an opening extending from the first end to the second end, the opening having an inner diameter that increases over at least a portion of the opening from the first end toward the second end; a tubular liner configured for deployment along an inside the pipeline, wherein the tubular liner is placed through the opening, wherein the opening at the second end is configured to receive the tubular liner as the grout dam device is moved along the pipeline, wherein the opening at the first end is smaller than the opening at the second end, and wherein the opening at the first end is configured to expel the tubular liner as the grout dam device is moved along the pipeline; and a seal coupled to the grout dam device, the seal configured to substantially fill a space between the grout dam device and an inner circumference of the inside of the pipeline. [0014] The system of any of paragraphs [0007] through [0013] may further include the opening increasing substantially linearly over at least a portion of the opening from the first end toward the second end.

[0015] The system of any of paragraphs [0007] through [0014] may further include an opening with a narrowing portion and a limiter portion, wherein the inner diameter of the opening remains substantially the same over the limiter portion, and wherein the inner diameter of the opening increases over the narrowing portion from the limiter portion toward the second end. [0016] An exterior of the grout dam device of any one of paragraphs [0005] through [0015] may be substantially hourglass-shaped.

[0017] The system of any of paragraphs [0005] through [0015] may include a seal that is a foam seal.

[0018] While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 illustrates a side cross sectional view of a pipeline and liner with a rounding swab and a grout dam device, according to embodiments of the present invention. [0020] While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

[0021] FIG. 1 illustrates a side cross sectional view of a pipeline 100 and liner 110 with a rounding swab 199 and a grout dam device 192, taken along a longitudinal centerline of the pipeline 100. Grout dam device 192 may also be referred to as a "back pressure" device. According to some embodiments of the present invention, sections of pipe 100 may be grouted and lined by using a grout dam device 192 which is pushed directly in front of swab 199 as swab 199 advances from front end 101 to back end 502. A similar relining and grouting process is described in U.S. Patent Application Serial No. 11/842,933, filed on August 21 , 2007, and published as U.S. Patent Application Publication No. US2008/0178955 on July 31 , 2008 (hereinafter referred to as the "'933 Application"), which is hereby incorporated by reference in its entirety for all purposes. FIG. 1 illustrates a back-pressure device 192, according to embodiments of the present invention. According to embodiments of the present invention, the elements of the system illustrated in FIG. 1 are substantially radially symmetrical about the longitudinal centerline of the pipe 100; hence, the view of FIG. 1 is both a side and a top cross-sectional view. [0022] Grout dam device 192 may be an hourglass-shape or dual cone shape device which accepts liner 110 in a folded, flat, and/or compressed state at one end 195 and permits the liner 110 to unfold and/or expand at the other end 180, according to embodiments of the present invention. The liner 110 is fed through a core hole extending through the grout dam device 192. The core hole, which may otherwise be referred to as an opening, is formed by the inner diameter 182 of the grout dam device 192, according to embodiments of the present invention. Liner 110 includes an inner diameter 187, and swab 199 is placed inside of the liner 110, according to embodiments of the present invention. As swab 199 is advanced forward in the direction of arrow 190 by the application of fluid into the space 1604 behind swab 199, swab 199 pushes against the inside of liner 110 and thus against the grout 191 between the liner 110 and the grout dam device 192, according to embodiments of the present invention. [0023] According to some embodiments of the present invention, the fluid applied into space 1604 is compressed air, air, compressed water, and/or water. According to some embodiments of the present invention, grout 191 is present between liner 110 and grout dam device 192, such that a distance 198 between grout dam device 192 and swab 199 as they advance forward in the pipe 100 may depend on the amount of grout 191 between liner 110 and grout dam device 192. Use of grout dam device 192 encourages more uniform distribution of grout 191 by maintaining a back pressure within the grout coverage area between liner 110 and pipe 100, and also prevents or hinders the introduction of air into the grout pocket between the liner 110 and pipe 100, according to embodiments of the present invention. As the swab 199 is advanced in the direction 190, the grout 191 is distributed between the liner 1 10 and the pipeline 100, opening the liner 110 to a circular cross-sectional shape after the liner 110 has been "rounded" by the swab pushing the liner 1 10 toward the pipeline 100 with the grout 191 in between, according to embodiments of the present invention. [0024] According to some embodiments of the present invention, an exterior surface of the grout dam device 192 has an hourglass shape as depicted, including a narrower neck portion 193 through which the liner 110 passes. The opening through the grout dam device 192 may include a narrowing portion 184 and a limiter portion 186, according to embodiments of the present invention. The inner diameter 182 of the grout dam device 192 increases along the narrowing portion 184 from the limiter portion 186 toward the end 195, according to embodiments of the present invention. The inner diameter 182 of the grout dam device 192 increases in a substantially linear fashion along the narrowing portion 184 in a direction toward the end 195, according to embodiments of the present invention. The inner diameter 182 is larger at end 195 than at end 180, according to embodiments of the present invention. [0025] The grout dam device 192 may also include a tube 196, which may also be referred to as a limiter tube or "lay flat" tube, which facilitates the entry of the liner tube 110 into the grout-filled space 191 between the grout dam device 192 and the swab 199 and liner 110, as the swab 199 and grout dam device 192 are advanced along the pipeline 100 in the direction of arrow 190. According to embodiments of the present invention, the grout end of the limiter tube 196 is end 180, and a device end 185 of the limiter tube 196 is coupled with the grout dam device 192. The limiter tube 196 encourages the liner 110 to lay flat and/or minimizes tearing and/or bunching of the liner 110, according to embodiments of the present invention. According to embodiments of the present invention, the liner tube 196 is formed with a relatively soft and flexible fiber-reinforced rubber hose, and is used to help confine the liner 1 10 with the assistance of the external grout pressure within the grout space 191. According to other embodiments of the present invention, the limiter tube 196 is semi-rigid or rigid. If the liner tube 110 were bent and/or tangled in the grout space 191 , the liner tube 110 might tear and/or it might push against the inside of the pipe 100, thereby inhibiting proper grout coverage of the area of the liner 110 pushing against the pipe 100. The limiter tube 196 serves to limit the radial extent of the liner 110 as it exits end 180, and serves to position the liner 110 radially in or near the longitudinal centerline of the pipe 100 for better grout distribution, according to embodiments of the present invention.

[0026] The semi-rigid tube 196 may include a front edge which is rounded, coned, and/or constructed of a softer more flexible material to encourage the liner 110 to move easily with respect to the tube 196, according to embodiments of the present invention. As shown in FIG. 1 , the distance 198 between swab 199 and grout dam device 192 will decrease as both swab 199 and device 192 are advanced from the front end 101 toward the back end 502, because a portion of the volume of grout 191 between the swab 199 and device 192 will be distributed between the liner 110 and the pipe 100 along the length of the pipe 100, and as this grout 191 volume decreases throughout the advancement of the swab 199 and device 192, the swab 199 will press the remaining volume of grout 191 against the grout dam device 192 and the pipe 100 walls, according to embodiments of the present invention.

[0027] The grout dam device 192 may also include a seal 194 around the front outer perimeter to inhibit or deter leakage of grout 191 past the grout dam device 194, and in order to maintain a back pressure between the liner 110 and the grout dam device 192, according to embodiments of the present invention. According to some embodiments of the present invention, the seal 194 permits the escape of air and a small amount of grout between the seal 194 and the host pipe 100, particularly when the pushing swab 199 is first inserted into the liner 110 at the front end 101 and advanced until all of the air above the grout 191 level between the liner 110 and the grout dam device 192 is pushed out over seal 194. According to some embodiments of the present invention, any grout 191 that escapes past seal 194 may accumulate in area 186. Although seal 194 is shown, based on the disclosure provided herein, one of ordinary skill in the art will recognize the various other materials, shapes, and placements of seal 194 that may be used to maintain a back pressure between pushing swab 199 and grout dam device 192, according to embodiments of the present invention. [0028] According to embodiments of the present invention, seal 194 is a lip- type seal. According to embodiments of the present invention, seal 194 is a foam seal. According to embodiments of the present invention, seal 194 is formed of a rubber, plastic, and/or other thermoplastic or elastomeric material, and may also be formed integrally with the grout dam device 192. According to embodiments of the present invention, the seal 194 is formed of a strip of fiber-reinforced rubber applied around the outer circumference of the grout dam device 192, which may also be clamped and/or retained around the grout dam device 192 in front of and/or behind seal 194 by straps welded to the grout dam device 192. [0029] A seal 188 may also be included at the outer perimeter of the back end 195 of the grout dam device 192, in order to further stabilize the device 192, provide better seal, and/or to permit smoother advancement of the device 192 along the inside of the host pipe 100, according to embodiments of the present invention. According to some embodiments of the present invention, seal 188 includes holes or discontinuities at one or more circumferential locations to permit air that escapes from the grout area 191 to escape past seal 194, past seal 188, and out the back end 502. According to some embodiments of the present invention, roller bearings (not shown) are provided at one or more axial and/or radial locations of the grout dam device 192, for example instead of seal 188, to further facilitate movement and stabilization of the device 192 within the pipe 100. [0030] Although an hourglass-type shape is shown for grout dam device

192, various other shapes may be used, which generally hold, group, and/or conform the liner 110 toward the center of the pipe 100 between the swab 199 and the grout dam device 192, so that the liner 110 between them does not fold, buckle, tear, or otherwise interfere with smooth, uninterrupted grout distribution along the inside of the pipe 100, according to embodiments of the present invention. The outer diameter 197 of the swab 199 is configured to provide a radial force to push the liner 110 and the grout 191 against the inner diameter of the pipe 100 as the swab 199 is advanced in the direction 190, according to embodiments of the present invention.

[0031] The grout dam device 192 may be formed of aluminum, according to embodiments of the present invention. The hourglass shape of the exterior of device 192 may be formed, for example, by joining the necks of two substantially conical sections, according to embodiments of the present invention. The grout dam device may also be formed of steel and/or plastic, according to embodiments of the present invention. The limiter tube 196 may be formed integrally with the rest of the grout dam device 192, or may be a separate substantially tubular element that is welded to, adhered to, or otherwise connected to or coupled with the rest of the grout dam device 192, according to embodiments of the present invention. The limiter tube 196 may also be made of aluminum, steel, sheet metal, felt, and/or plastic, according to alternative embodiments of the present invention.

[0032] According to embodiments of the present invention, swab 199 is a slightly deformable plug-type device which fills an inside diameter of pipe 100 and/or inside diameter 187 of liner 110, thereby applying a radial force to such inside diameter 187. For example, swab 199 may be constructed with a stiff foam, and may be sized so as to fit within pipe 100 and/or liner 110 only upon contraction and/or compression of the outer diameter of the swab 199. Swab 199 may be moved along pipe 100 and/or liner 110 by applying a force to one side of swab 199; such force may be applied, for example, by applying an air or water pressure to one side of swab 199, where swab 199 forms a substantially hermetic seal with inner diameter 187, for example.

[0033] According to some embodiments of the present invention, the swab

199 may be formed by starting with an appropriately-sized piece of foam, then piercing the foam axially through the center with a piece of rebar. The rebar may be left in place, and a length of 0.5mm to 1.0mm linear low density polyethylene ("LLDPE") tube is taped to the rebar and then pulled through the center of swab 199 with the rebar. The LLDPE tube is then cuffed back to completely cover the swab, and the excess plastic is twisted into a tail 1804, wrapped in tape, and turned back onto itself to form an eyelet, according to embodiments of the present invention. Tail 1804 and the eyelet formed therein may be used for tying or otherwise attaching things to swab 199; for example, a foot meter line may be tied onto the tail 1804 for monitoring the longitudinal position of swab 199 within pipe 100.

[0034] According to embodiments of the present invention, the tubular liner

110 may be a polyethylene tube, and may include grout hooks or other protrusions formed on an outside of the tube 110 which are embedded into the grout between the liner 110 and the pipeline 100. According to embodiments of the present invention, the tubular liner 110 is similar to that described in U.S. Patent No. 6,167,913, issued on Jan. 2, 1001 , which is incorporated herein by reference in its entirety.

[0035] Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.