Method of restoring a damaged tube

Abstract

A method of restoring a damaged pipe is provided. The method includes providing a liner formed of a polymeric-based material and / or an elastomeric-based material, the liner including an outer surface; applying a slurry to the outer surface of the liner, wherein the outer surface of the liner includes a groove, the slurry being contained in the groove to hold the slurry in place when the liner is disposed in the damaged pipe; disposing the liner on a puller-sealer fixture having a U-shaped cross-section; pulling the puller-sealer fixture attached to a rolling cart by a cable to thereby pull the puller-sealer fixture and the liner with the slurry through the damaged pipe, wherein the puller-sealer fixture holds the liner in place while the liner is pulled through the damaged pipe; and exposing the slurry on the outer surface of the liner to moisture, ultraviolet radiation, heat, and / or ultrasonic waves; the step of exposing causes the slurry to expand and contact an inner diameter surface of the damaged pipe.

Description

[0001] This application is a divisional application of patent application No. 202110938222.8, filed on January 31, 2017 (divisional filing date: August 16, 2021), entitled "Component for Restoring a Damaged Tube". Furthermore, patent application No. 202110938222.8 is itself a divisional application of patent application No. 201780009323.9, filed on January 31, 2017, entitled "Component for Restoring a Damaged Tube".

[0002] Cross-reference to related applications

[0003] This U.S. patent application claims priority to U.S. Provisional Patent Application No. 62 / 289,760, filed February 1, 2016; U.S. Provisional Patent Application No. 62 / 432,265, filed December 9, 2016; and U.S. Patent Application No. 15 / 419,525, filed January 30, 2017, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0004] This invention relates to products and methods for restoring damaged pipelines. Background Technology

[0005] Grout is commonly used to repair the inner surfaces of corroded, cracked, or otherwise damaged pipes. One method for repairing metal pipes involves linking short links of stainless steel sleeves together to form a liner and pulling the stainless steel liner through the metal pipe with a cable to create a small annular space between the stainless steel liner and the metal pipe. Grout is then pumped into the annular space to fill the annular space and cracks in the metal pipe. However, this method involves significant material and labor costs. Furthermore, in the above method and other currently used methods, it is difficult to control the placement of the grout. Typically, the grout is unevenly placed along the damaged pipe and does not fill all the cracks in the pipe.

[0006] Another recently developed method for repairing damaged pipes with slurry involves using an expandable tube. The expandable tube includes a liner and slurry disposed in grooves along the outer surface of the liner. The liner with slurry is placed in an opening in the damaged pipe and then exposed to moisture, causing the slurry to expand and bond to the inner surface of the damaged pipe.

[0007] The grooves in the liner allow the expandable tube to be folded for easy transport. The grooves also provide flexibility in manipulating the expandable tube near bends in the damaged pipe. The grooves also allow control over the placement and amount of grout along the outer surface of the liner. The grooves hold the grout in place while the liner is in place in the damaged pipe. The grout expands to engage the inner surface of the damaged pipe and fill cracks, holes, notches, or other defects and voids along the inner surface of the pipe caused by corrosion, erosion, or other conditions. In other words, the expandable tube replaces the liner on the inner surface of the damaged pipe. The expandable tube also provides a seal to the pipe and prevents water and debris from entering. The grout in the expandable tube can also expand through holes in the pipe and fill voids in the soil surrounding the pipe. Expandable tubes are a cost-effective and convenient method for repairing and restoring various types of pipes—such as sewer pipes, drinking water pipes, electrical conduits, and air pipes. An example of an expandable tube is provided in U.S. Patent No. 7,942,167. Summary of the Invention

[0008] One aspect of the invention provides an expandable tube for restoring a damaged tube. The expandable tube includes a liner formed of thermoplastic polyurethane and having an outer surface. The outer surface of the liner includes a plurality of expansion tips and grooves, with each groove located between adjacent expansion tips. A slurry is disposed on the expansion tips and in the grooves of the liner. The slurry is dimensionally expandable upon exposure to moisture, ultraviolet radiation, heat, and / or ultrasound.

[0009] According to another embodiment, the expandable tube includes a liner formed of a polymer-based material and / or an elastomeric-based material, and the liner contains multiple fibers. The liner includes an outer surface, and the outer surface of the liner includes multiple grooves. A slurry is disposed in the grooves of the liner, and the slurry is dimensionally expandable upon exposure to moisture, ultraviolet radiation, heat, and / or ultrasound.

[0010] Another aspect of the invention provides a method for manufacturing an expandable tube for restoring a damaged tube. The method includes extruding a liner from a thermoplastic polyurethane, wherein the extruded liner includes an outer surface having a plurality of expandable tips and grooves, each groove located between adjacent expandable tips. The method further includes disposing a slurry on the expandable tips and in the grooves of the liner, wherein the slurry is dimensionally expandable upon exposure to moisture, ultraviolet radiation, heat, and / or ultrasound.

[0011] According to another embodiment, a method of manufacturing an expandable tube for restoring a damaged tube includes extruding a liner formed from a polymer-based material and / or an elastomeric-based material and comprising multiple fibers, wherein the extruded liner includes an outer surface having multiple grooves. The method further includes disposing a slurry in the grooves of the liner, wherein the slurry is dimensionally expandable upon exposure to moisture, ultraviolet radiation, heat, and / or ultrasound.

[0012] Another aspect of the invention provides a method for restoring a damaged tube. The method includes: providing a liner formed of a polymer-based material and / or an elastomeric-based material, the liner including an outer surface; and applying a slurry to the outer surface of the liner. The method further includes placing the liner on a pull-out seal holder having a U-shaped cross-section and pulling the pull-out seal holder and the liner with slurry through the damaged tube. The method also includes exposing the slurry on the outer surface of the liner to moisture, ultraviolet radiation, heat, and / or ultrasound, the exposure step causing the slurry to expand and contact the inner diameter surface of the damaged tube. Attached Figure Description

[0013] As other advantages of the invention become better understood when considered in conjunction with the following detailed description, in which the accompanying drawings are taken, these advantages will readily be appreciated:

[0014] Figure 1 This is a cross-sectional view of a portion of the lining according to an exemplary embodiment of the present invention;

[0015] Figure 2 This is a cross-sectional view of the entire lining disposed inside the main tube according to an exemplary embodiment of the present invention;

[0016] Figure 3 It is a cross-sectional view of a pull-out sealer fixing device installed inside the main pipe, which constructs the liner to pass through the main pipe with minimal interference with the inner diameter of the main pipe and seals the inner diameter of the liner relative to water, debris and slurry.

[0017] Figure 4 The illustration shows a jet fixing device and a pull-out seal fixing device attached to a rolling carriage for installing the liner in the main pipe.

[0018] Figure 5 An example of an impregnation tank assembly for coating a liner with a 1-part moisture-cured urethane slurry, according to an exemplary embodiment, is illustrated; and

[0019] Figure 6 Exemplary specifications for coating tanks and mixing tanks, including impregnation tank assemblies according to exemplary embodiments. Detailed Implementation

[0020] In the relevant U.S. provisional patent application no. 62 / 289760 Figures 1 to 1 Figure 3 shows an expandable pipe 20 for repairing a damaged pipe 22, also known as a main pipe. The damaged pipe or main pipe 22 is a pipe located in the ground that needs repair. For example, the expandable pipe 20 can be used to repair or restore various types of pipes or main pipes 22, such as water pipes, gas pipes, oil pipes, sewer pipes, drinking water pipes, electrical conduits, and air ducts.

[0021] The expandable tube 20 includes a modified liner 24 formed of a polymer-based material and / or an elastomeric-based material, and a slurry 30 applied to the outer surface 26 of the liner 24. The outer surface 26 of the liner 24 may include grooves 28 or molded surfaces to hold the slurry 30 in place when the liner 24 is arranged in the main tube 22. The slurry 30 expands in size D1, such as volume, upon exposure to moisture, ultraviolet (UV) radiation, heat, and / or ultrasound, or upon contact with moisture, UV radiation, heat, and / or ultrasound. Moisture, UV radiation, heat, and / or ultrasound can also cause the slurry 30 to cure. Thus, after such exposure, the slurry 30 contacts the inner diameter surface of the damaged main tube 22 and fills voids in the damaged main tube 22. The volume of the expanded slurry 30 is 1% to 1000% larger than the volume of the slurry 30 before expansion. The slurry 30 then hardens to restore the integrity of the main tube 22. In addition to the embodiments described in U.S. Provisional Patent Application No. 62 / 289760, there may be several other embodiments, which are referred to herein by reference. Figures 1 to 4 Describe it.

[0022] As described above, the liner 24 is formed of a polymer-based material and / or an elastomer-based material. The liner 24 may be formed from a single polymer-based material or an elastomer-based material—for example, a thermoplastic material. Alternatively, the liner 24 may include more than one polymer and / or elastomer. According to an exemplary embodiment, the liner 24 is extruded from a transparent thermoplastic polyurethane (TPU). The transparent liner 24 is preferably used for observation purposes, such as observing the interior of the recovering damaged tube 22 using a camera. However, the liner 24 may be another color and does not have to be transparent to function as intended. The liner 24 may also have another composition. For example, the liner 24 may be formed from any foldable and expandable material, not limited to TPU. For example, the liner 24 may be formed from polyethylene or any medium-density plastic. The liner 24 may optionally include fibers in the polymer-based material and / or the elastomer-based material, at least in the thin base of the liner 24, to increase strength and prevent the liner 24 from bulging. For example, the liner 24 may include a combination of various polymers and / or elastomers and reinforcing fibers. The visual clarity of the TPU allows for easy video identification of the side entry point, enabling the trimming of the liner 24. After the liner 24 is installed in the main tube 22, the inner diameter surface 32 of the liner 24, which is positioned opposite to the outer surface 26, is smooth.

[0023] According to a preferred embodiment, the grooves 28 of the liner 24 are achieved by contours on the outer surface 26 of the liner 24, also referred to as the outer diameter surface, such as... Figure 1 and Figure 2 As shown. In Figure 1 and Figure 2In one embodiment, the outline of the outer surface 26 of the lining 24 includes an expanded tip 34, which serves as a mechanical lock for the slurry 30 applied to the outer surface 26 of the lining 24. Although Figure 1 Only a portion of the expansion tip 34 along the outer surface 26 of the liner 24 is shown, but the expansion tip 34 is preferably positioned along the entire outer surface 26 of the liner 24 and continuously surrounds the outer periphery of the liner 24. Figure 1 and Figure 2 In the example, each groove 28 is formed between two adjacent expansion tips 34, and the slurry 30 is contained in these grooves 28. The expansion tip 34 includes a rod 36 extending perpendicularly to the base of the liner 24 and an enlarged top 38 expanding outward relative to the rod 36. The diameter or width of the enlarged top 38 is greater than the diameter or width of the rod 36. Figure 1 and Figure 2 The expanded tip 34 shown is merely an example, as its shape and size can vary. Alternatively, other shaped and sized moldings can be used to achieve the groove 28 in the liner 24. However, if sufficient bonding is achieved between the liner 24 and the slurry 30, the expanded tip 34 or other mechanical locking features are not required.

[0024] The liner 24 can be formed by extrusion, preferably in a flat extrusion die, to produce a flat product, such as a TPU sheet or a sheet of another thermoplastic material. The flat extruded product is then welded into a cylindrical shape to produce the liner 24 so that it remains within the main tube 22, as... Figure 2 As shown in the diagram. In other words, the flat product is welded at its circumference, matching the desired diameter of the liner 24. The diameter of the liner 24 when inflated should be smaller than the inner diameter of the main pipe 22. For example, in an exemplary embodiment, the liner 24 has an inner diameter of 7.5 inches when inflated, and the main pipe 22 has an inner diameter of 8 inches. The liner 24 can be extruded as a round tube to a certain size, but some raw materials are difficult to extrude into a circular geometry due to a lack of melt strength. Another advantage of extruding flat parts and welding is the ability to obtain any diameter with limited tools.

[0025] According to an exemplary embodiment, during the installation of the liner 24 into the main pipe 22, a slurry 30, preferably a urethane slurry such as unactivated liquid polyurethane, is applied to the outer surface 26 of the liner 24. The slurry 30 may optionally contain fibers to increase strength. At this time, the liner 24 is folded flat for installation. Before the liner 24 enters the main pipe 22, the outer surface 26 of the liner 24 is coated with a 1-part moisture-curing urethane slurry. This slurry 30 cures and expands during installation, thereby adhering to the TPU liner 24 and the main pipe 22.

[0026] As will be further discussed below, in an exemplary embodiment, a 2-part urethane slurry is sprayed onto the inner diameter surface of the main pipe 22 during installation. In other words, urethane slurry is sprayed onto the inner diameter surface of the main pipe 22 during installation, and as the TPU liner 24 is pulled through the main pipe 22 by the cable 40 and the rolling trolley 42, a set of mixing / spraying heads 44 mounted to the rolling trolley 42 (just in front of the liner 24 as it is pulled through the main pipe 22) sprays a coating of the 2-part urethane slurry (optionally including fiber-encapsulated material) onto the inner diameter surface of the main pipe 22. The 2-part urethane slurry comprises a 1-part urethane and a 1-part curing agent. The 1-part expanded urethane slurry, combined with the 2-part expanded urethane slurry sprayed onto the inner diameter surface of the main pipe 22 as the liner 24 is pulled through the main pipe 22, is applied to the outer surface 26 of the liner 24 before it enters the main pipe 22 to provide a high-strength and highly adhesive joint between the liner 24 and the main pipe 22, and also migrates and expands to fill any cracks, voids or defects in the main pipe 22 or adjacent maintenance lines.

[0027] Now refer to Figure 3 and Figure 4 The method of installing the liner 24 in the main pipe 22 according to the example embodiment is described in more detail. When the TPU liner 24 is ready for installation, the TPU liner 24, laid flat like a fire hose, is wound onto a reel. At the construction site where the main pipe 22 is located, the liner 24 is guided through the impregnation (or soaking) tank assembly 56 containing a one-part moisture-curing urethane slurry. Figure 5 The illustration shows a liner 24 being guided through an impregnation tank assembly 56 according to an exemplary embodiment. The impregnation tank assembly 56 is capable of uniformly coating the liner 24 with a 1-part moisture-curing urethane paste, such as unactivated liquid polyurethane. The impregnation tank assembly 56 is also capable of applying a 1-part moisture-curing urethane paste to the liner 24, which has a diameter of 2 inches to 20 feet, for example, a diameter of 6 inches to 12 inches. The impregnation tank assembly 56 is structurally robust, easy to maintain and repair, and has portable properties. Figure 5As shown, the impregnation tank assembly 56 includes a coating tank 58 that guides the liner 24 through liquid polyurethane using a series of vertical and horizontal rollers 60. Guide rollers 60 guide the liner 24 from the supply section into the coating tank 58, and also guide the coated liner 24 from the coating tank 58 to an inspection hole where it will be used to repair damaged pipe 22. The coating tank 58 is typically formed of aluminum and includes a removable top 62 and a discharge section 64. However, the design and materials used to form the coating tank 58 can vary. The rollers 60 are typically formed of ultra-high density polyurethane. However, the impregnation tank assembly 56 may include different arrays of rollers 60, and / or the rollers 60 may be formed of different materials. The impregnation tank assembly 56 also includes a mixing tank 66, which serves as a reservoir for supplying additional liquid polyurethane to the coating tank 58 as needed to maintain the liquid level in the coating tank 58. The mixing tank 66 may also be formed of aluminum or other materials. Figure 6 Exemplary specifications for coating tank 58 and mixing tank 66 are provided. These specifications are essentially generic and can be adjusted as needed prior to manufacturing the impregnation tank assembly 56.

[0028] The TPU liner 24 is guided downwards into the opening of the main pipe 22 while its outer surface 26 is immersed in urethane slurry. For example... Figure 3 and Figure 4 As shown, the TPU liner 24 is attached to the jetting fixture 46 at the opening via a pull-out sealer retainer 48. The pull-out sealer retainer 48 is a solid material component used as a mounting fixture, which configures the liner 24 to optimally pass through the main pipe 22 with minimal interference to the inner diameter surface of the main pipe 22. In an exemplary embodiment, the pull-out sealer retainer 48 has a U-shaped cross-section and no sharp edges. The pull-out sealer retainer 48 holds the liner 24 in place without any sharp edges along it. In an exemplary embodiment, the pull-out sealer retainer 48 has an outer perimeter of 23.560 inches, which is equal to the length of the liner 24 with an inner diameter of 7.5 inches. A clamp or holder 50 may be used to secure the liner 24 to the pull-out sealer retainer 48. The pull-out seal retainer 48 also prevents debris, moisture, and / or slurry 30 from entering the interior of the liner 24. For example, the clamp 50 can secure the liner 24 tightly against the pull-out seal retainer 48 to prevent debris, moisture, and / or slurry 30 from entering the interior of the liner 24. During installation, the pull-out seal retainer 48 is attached to the rolling trolley 42 and pulled through the main pipe 22 by the cable 40.

[0029] The carriage 42 is also attached to a set of mixing / spraying heads 44, which are pulled through the main pipe 22 during installation. The mixing / spraying heads 44 receive two urethane slurry feed lines 52, 54 from the pulling side, for example, along the cable. The mixing / spraying heads 44 mix the 2-part slurry and then spray the mixture onto the inner diameter surface of the main pipe 22. One feed line 52 contains urethane and the second feed line 54 contains a curing agent. The flow rate into the mixing / spraying heads 44 is automatically controlled according to the speed of the carriage 42 and the entire assembly through the main pipe 22 to ensure consistent coating of the main pipe 22. Therefore, the area between the liner 24 and the main pipe 22 is filled with both 1-part urethane and 2-part urethane slurry. Once the entire length of the TPU liner 24 has been pulled through the main pipe 22, the ends of the liner 24 are capped, and the liner 24 is inflated to a specific pressure. The slurry 30 is exposed to moisture, ultraviolet radiation, heat, and / or ultrasound, and thus cures and expands to adhere to the lining 24 and the inner diameter surface of the damaged pipe 22. The slurry 30 is typically in foam form and adheres to the extruded lining 24, forming an adhesive bond, and preferably a cohesive bond, such that the lining 24 and the slurry do not require the plurality of expansion tips 34 to maintain contact. After a suitable curing period, the internal pressure of the lining 24 is released. The ends and sides (access points for maintenance lines) of the lining 24 can then be trimmed.

[0030] Obviously, based on the foregoing teachings, the invention can be modified and varied in many ways within the scope of the appended claims, and these modifications and variations can be practiced in ways other than those specifically described.

Claims

1. A method for restoring a damaged tube, comprising the following steps: A liner formed of a polymer-based material and / or an elastomer-based material is provided, the liner including an outer surface. The slurry is applied to the outer surface of the lining, wherein... The outer surface of the lining includes grooves in which the slurry is received to hold the slurry in place when the lining is placed in the damaged pipe. The liner is mounted on a pull-out sealer fixing device with a U-shaped cross-section. Pulling the puller-seal fixing device attached to the rolling trolley via a cable pulls the puller-seal fixing device and the lining containing the slurry through the damaged tube, wherein the puller-seal fixing device holds the lining in place while pulling it through the damaged tube, and The slurry on the outer surface of the lining is exposed to moisture, ultraviolet radiation, heat and / or ultrasound. The exposure step causes the slurry to expand and come into contact with the inner diameter surface of the damaged pipe.

2. The method according to claim 1, wherein, The cross-section of the pull-out sealer fixing device does not include sharp edges.

3. The method according to claim 1, wherein, The outer surface of the liner includes a plurality of expansion tips and a plurality of grooves, each groove being located between adjacent expansion tips. Each expansion tip of the liner includes a rod extending perpendicular to the base of the liner and an enlarged top expanding outward relative to the rod, the width of the enlarged top being greater than the width of the rod.

4. The method according to claim 1, wherein, The lining is secured to the puller-seal fixing device by a clamp that prevents debris, moisture and / or the slurry from entering the interior of the lining.

5. The method according to claim 1, wherein, The step of applying the slurry to the outer surface of the lining includes applying an unactivated liquid polyurethane slurry to the outer surface, the slurry further comprising a 2-part urethane slurry, and further comprising spraying the 2-part urethane slurry onto the inner diameter surface of the damaged tube while pulling the puller-seal fixing device and the lining through the damaged tube, the 2-part urethane slurry comprising urethane and a curing agent.

6. The method according to claim 5, wherein, The spraying step includes spraying the 2-part urethane slurry through a spray head attached to the front of the liner to the rolling carriage, the spray head receiving two feed lines laid along the cable, one of the feed lines containing the urethane and the other feed line containing the curing agent.

7. The method according to claim 5, wherein, The step of applying the unactivated liquid polyurethane slurry to the outer surface of the lining includes guiding the lining through an impregnation tank assembly that contains the unactivated liquid polyurethane slurry.

8. The method of claim 1, further comprising exposing the slurry to moisture, ultraviolet radiation, heat and / or ultrasound, causing the volume of the slurry to expand by 1% to 1000%, and the slurry to solidify and adhere to the lining and the inner diameter surface of the damaged pipe.

9. The method according to claim 1, wherein, The step of providing the liner includes extruding a flat plate made of a polymer-based material and / or an elastomer-based material, and welding the flat plate to form the liner.

10. The method according to claim 1, wherein, The step of providing the lining includes extruding the lining from a transparent thermoplastic polyurethane comprising fibers. The outer surface of the liner includes a plurality of expanding tips and a plurality of grooves, each groove being located between adjacent expanding tips. The expanding tips are positioned along the entire outer surface of the liner and continuously surround the outer circumference of the liner. Each of the expanding tips of the liner includes a rod extending perpendicular to the base of the liner and an enlarged top expanding outward relative to the rod, the width of the enlarged top being greater than the width of the rod. The extrusion step of the lining is performed using an extrusion die that produces a flat sheet made of the thermoplastic polyurethane containing fibers. The step of providing the liner further includes welding the flat plate to produce the liner, wherein the diameter of the liner when inflated is smaller than the diameter of the inner diameter surface of the damaged tube. The lining has a diameter of 6 to 12 inches when inflated. The cross-section of the pull-out seal fixing device does not include sharp edges. The step of applying the slurry to the outer surface of the lining includes placing unactivated liquid polyurethane slurry on the expansion pin and in the groove, the expansion pin and the groove retaining the unactivated liquid polyurethane slurry on the outer surface of the lining during the step of pulling the lining through the damaged tube. The unactivated liquid polyurethane paste contains fibers and expands in volume by 1% to 1000% when the paste is exposed to moisture. The step of setting the unactivated liquid polyurethane paste on the expansion tip and in the groove includes applying the unactivated liquid polyurethane paste to the outer surface of the lining while the lining is flat, wherein the unactivated liquid polyurethane paste is cured by moisture. The step of placing the unactivated liquid polyurethane slurry on the expansion tip and in the groove includes guiding the liner through an impregnation tank assembly that contains the unactivated liquid polyurethane slurry. The impregnation tank assembly includes a coating tank that uses a series of rollers formed of ultra-high density polyurethane to guide the lining through the unactivated liquid polyurethane slurry. The coating tank is made of aluminum and includes a removable top and a discharge section. The impregnation tank assembly also includes a mixing tank formed of aluminum, which provides a reservoir for the unactivated liquid polyurethane slurry and supplies the unactivated liquid polyurethane slurry to the coating tank. The pull-out seal fixing device is a solid material component and has no sharp edges along the lining. The lining is secured to the pull-out sealer fixing device by clamping members, which prevent debris, moisture, and / or the slurry from entering the interior of the lining. It also includes spraying a 2-part urethane slurry onto the inner diameter surface of the damaged tube while pulling the puller-seal fixing device and the lining through the damaged tube, the 2-part urethane slurry comprising urethane and a curing agent. The spraying step includes spraying the 2-part urethane slurry through a spray head attached to the front of the lining and to the rolling carriage. The spray head receives two feed lines laid along the cable, one feed line comprising the urethane and the other feed line comprising the curing agent. The urethane and the curing agent are mixed before the 2-part urethane slurry is sprayed onto the inner diameter surface of the damaged pipe. The slurry comprises a mixture of the unactivated liquid polyurethane slurry located on the outer surface of the lining and the 2-part urethane slurry located on the inner diameter surface of the damaged pipe. It also includes the steps of capping the end of the liner after spraying the 2-part urethane slurry onto the inner diameter surface of the damaged tube and inflating the liner to a specific pressure. The exposure step includes exposing the slurry to moisture, causing the slurry to expand in volume by 1% to 1000%, the slurry curing and adhering to the lining and the inner diameter surface of the damaged pipe, and... After the slurry has cured, the pressure on the inflated lining is released.

11. The method according to claim 1, wherein, The step of providing the lining includes extruding the lining from a thermoplastic material, applying the slurry to the outer surface of the lining in foam form, and forming an adhesive or bonding bond between the slurry and the extruded lining such that the lining and the slurry do not require multiple expanded tips on the outer surface of the extruded lining to maintain contact.

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