A pipe lining apparatus and method

Abstract

There is disclosed a lining arrangement for a pipe, wherein the lining arrangement comprises: a first tubular layer configured to be situated within the pipe; a pressure providing element; wherein the first tubular layer is configured to line an inner pipe surface of the pipe when the first tubular layer is in a radially tensioned state; and wherein the pressure providing element is configured to apply pressure to the first tubular layer such that the first tubular layer is stretched from a non-radially tensioned state to the radially tensioned state.

Description

[0001] A Pipe Lining Apparatus and Method

[0002] Field of Invention

[0003] The present invention is in the field of apparatus and methods for the creation of linings inside pipes, such as water pipes, and waste pipes, to increase the lifespan of said pipes by either plugging holes, or providing structural support to areas of the pipe with a weakness or failure point.

[0004] Background to Invention

[0005] Pipes are often positioned in subterranean locations and can be used for the movement of fluids from one location to another. Such fluids may include water, waste (such as slurry or sewage), gas, oil or the like. These pipes may be in use for a number of years, or even decades in some instances. Due to this use the pipes are liable to corrosion or damage. Moreover, freeze thaw and high moisture content may cause heave of the ground in winter and may in particular cause damage to pipes. Further, ground in the summer that is parched of moisture may contract, and as a result, further ground movement may occur which can further cause damage to the pipes.

[0006] Due to the expense of excavating subterranean pipes in order to replace them, it is highly advantageous to be able to repair the pipes in situ. At present, one repair methodology utilises an applicator head that is pulled through a pipe, and the applicator head applies a coating to the pipe. However, the coating is only suitable to cover holes that have a diameter that is approximately twice the size of the thickness of the coating. Beyond this size, the coating is unlikely to successfully cover the defect and is likely to fail. This places a very low limitation on the type of repair available. Moreover, this repair provides very little structural support to the pipe itself.

[0007] It can also be possible that the spray applied liner adheres to the inner wall of the pipe. However, any movement in the pipe walls as a result of pipe fracture will cause a similar movement in the newly adhered sections and will also result in failure of the liner. Therefore this provides only very limited improvement to the strength and performance of the pipe.

[0008] There is a need to provide a new apparatus and method for more effective repair and strengthening of subterranean pipes.

[0009] Statements of Invention Aspects of the invention are set out in the independent claims. Optional features are set out in the dependent claims.

[0010] In accordance with a first aspect there is described a lining arrangement for a pipe, wherein the lining arrangement comprises: a first tubular layer configured to be situated within the pipe; a pressure providing element; wherein the first tubular layer is configured to line an inner pipe surface of the pipe when the first tubular layer is in a radially tensioned state; and wherein the pressure providing element is configured to apply pressure to the first tubular layer such that the first tubular layer is stretched from a non-radially tensioned state to the radially tensioned state. This may be advantageous because the radially tensioned state allows the first tubular layer to be deployed within a pipe, and flush to the pipe, without being adhered to the pipe. The radially tensioned state may allow for the lining and strengthening of damaged subterranean pipes.

[0011] Optionally, the lining arrangement further comprises an applicator head configured to spray line an inner surface of the first tubular layer with a fluid. This may allow the inner surface to be lined such that the pipe is impervious to the fluid it is configured to carry (e.g. water, gas or oil).

[0012] In accordance with a second aspect of the invention there is described a lining arrangement for a pipe, wherein the lining arrangement comprises: a first tubular layer configured to be situated within the pipe; and an applicator head configured to spray line an inner surface of the first tubular layer with a fluid. This may allow a first tubular layer to sit within the pipe, and this first tubular layer (rather than the pipe itself) to be lined. This may enable a more consistent and full lining to take place (particularly at pipe joints or other large discontinuities in the pipe surface).

[0013] Optionally, further comprising a pressure providing element; wherein the first tubular layer is configured to line an inner pipe surface of the pipe when the first tubular layer is in a radially tensioned state; and wherein the pressure providing element is configured to apply pressure to the first tubular layer such that the first tubular layer is stretched from a non-radially tensioned state to the radially tensioned state. This may be advantageous because the radially tensioned state allows the first tubular layer to be deployed within a pipe, and flush to the pipe, without being adhered to the pipe. The radially tensioned state may allow for the lining and strengthening of damaged subterranean pipes. The following optional features may be optional to either, or both, of the first and second aspects set out above.

[0014] Optionally, the pressure providing element is positioned at a first end of the pipe or at a first end of a first tubular layer within the pipe, and is configured to provide air into the first tubular layer. This may be advantageous for expanding the first tubular layer into its radially tensioned state.

[0015] Optionally, further comprising an end block positioned at a second end of the pipe or at a second end of the first tubular layer within the pipe, and is configured to minimise air escaping from the first tubular layer. This may reduce the pressure required, allow for an even pressure throughout the length of the first tubular layer (reducing the chance of failure of the first tubular layer from overexpansion at one location), and reduce energy consumption.

[0016] Optionally, the end block traps a volume of air within the first tubular layer and allows the air pressure within the first tubular layer to be raised by the pressure providing element. This may reduce the pressure required, allow for an even pressure throughout the length of the first tubular layer (reducing the chance of failure of the first tubular layer from overexpansion at one location), and reduce energy consumption.

[0017] Optionally, wherein the lining arrangement further comprises a second end block.

[0018] Optionally, wherein the second end block is positioned on a second side of the pressure providing element to the first tubular layer. The second end block of the above two statements and its positioning may form an arrangement that further minimises air escaping by trapping air on both sides of the first tubular layer. This may further allow the pressure providing element to deliver air to the pipe through a portion of the pipe wall instead of the end of a pipe. It may also prevent the need for a complete seal around the pressure providing element when delivering air into the pipe.

[0019] Optionally, the pressure provided by the pressure providing element is in the pressure range of 0.3 to 0.5 Bar. This pressure may be particularly advantageous for expanding the first tubular layer to the radially tensioned state, without over-expanding, or overstressing, the first tubular layer.

[0020] Optionally, the pressure providing element is a compressor, pressurised gas cylinder or air pump. This may be an efficient way of increasing the pressure within the first tubular layer. Optionally, the pressure providing element is configured to provide a pressure to maintain the first tubular layer in the radially tensioned state until the spray lined inner surface is hardened or cured. This may enable the cured surface to be uniform.

[0021] Optionally, the applicator head comprises a spinning element, wherein the spinning element is configured to spin such that the centrifugal force on the fluid forces the fluid to exit the applicator head and line the inner surface of the first tubular layer. This may allow an even surface to be created.

[0022] Optionally, the lining arrangement further comprises a pulling element configured to pull the applicator head through the first tubular layer such that a length of the inner surface of the first tubular layer is lined by the fluid. This may allow the duration of the coating process and the lining thickness applied for each section of the first tubular layer to be controlled, by controlling the speed at which the applicator head is pulled.

[0023] Optionally, once cured the fluid is configured to form a second layer, optionally wherein the second layer is adhered to the inner surface of the first tubular layer, further optionally wherein the second layer is configured to form a second tubular layer. This dual layer may provide both structural support to the pipe, and ensure the pipe is impervious to fluids.

[0024] Optionally, once cured the second layer is configured to constrain the first tubular layer and so maintain the radial tension within the first layer. This allows the first tubular layer to permanently provide structural support to the pipe.

[0025] Optionally, the second layer is configured to cure-in-place onto the inner surface of the first layer. This allows the inner surface to be cured in situ.

[0026] Optionally, the fluid comprises a mixture of two liquid polymers, optionally wherein the applicator head is configured to mix the two liquid polymers. This may allow for the constitute parts of the polymer to be mixed at the point of application to minimise the time prior to application.

[0027] Optionally, an outer surface of the first tubular layer is configured to abut an inner surface of the pipe. This allows the first tubular layer to provide structural support to the pipe, and to in effect form a pipe within the pipe.

[0028] Optionally, the abutment is configured such that a portion of the first tubular layer is displaceable relative to the inner surface of the pipe that the first tubular layer is abutting. This may be highly advantageous as should there be external forces on the pipe, then these may not directly effect the first tubular layer. In this way the first tubular layer may form a stronger internal pipe within the pipe that is less likely to be prone to failure.

[0029] Optionally, the abutment between the first tubular layer and the inner surface of the pipe is characterised as a non-adhesive abutment. This may allow sufficient give between the pipe and the first tubular layer to prevent damage when excess forces are applied to the pipe.

[0030] Optionally, the first tubular layer is a stretchable structure, optionally wherein the first tubular layer is configured to be stretched from a non-radially tensioned state to a radially tensioned state.

[0031] Optionally, the first tubular layer is radially tensioned with mechanical means, or wherein it is radially stretched with mechanical means. This may provide an embodiment in which a pressure means is not needed, or is not possible to use.

[0032] Optionally, the first tubular layer has a smaller diameter than the inner diameter of the pipe when the first tubular layer is in an un-tensioned state. This allows ease of access for the first tubular layer prior to the pressurisation.

[0033] Optionally, the first layer is made from an airtight polymeric film or layer, for example polyurethane. This may allow the pressurisation to expand the first tubular layer into the radially tensioned state.

[0034] Optionally, first tubular layer has a thickness between 0.5mm and 3mm. This may provide sufficient strength, whilst enabling a sufficient pressure to cause the first tubular layer to expand.

[0035] Optionally, the first tubular layer has a greater stiffness than the second layer. This may enable the first tubular layer to provide structural support to the pipe.

[0036] Optionally, the first tubular layer is configured to herniate through an aperture, hole or crack in the pipe surface. This may allow the hole or crack to be filled, and to strengthen the pipe at these weak points.

[0037] Optionally, the profile of the herniation is tapered from the portion of the first tubular layer directly overlying the boundary of the aperture, hole or crack of the pipe surface to the centre of the hernia. This may prevent a tear, fold or other weakness developing in the first tubular layer due to the herniation.

[0038] Optionally, the first tubular layer is configured to form a bridge across an aperture, hole, pipe joint or crack in the inner pipe surface, and wherein the second layer is configured to line the bridging portion. This may allow the pipe to be strengthened at these areas of weakness.

[0039] In accordance with a third aspect of the invention there is provided an internal pipe segment for lining an outer pipe, wherein the internal pipe segment comprises; a first tubular layer; and a second layer; wherein the outer surface of the first tubular layer is configured to abut an inner surface of the outer pipe; and wherein the second layer is configured to be cured onto the inner surface of the first tubular layer. This may advantageously provide an internal pipe to allow a pipe section to be used, even though it has decayed or otherwise been damaged.

[0040] Optionally, the internal pipe segment forms a rigid structure within the outer pipe. This may provide structural support to the outer pipe.

[0041] Optionally, the pipe segment comprises a herniated portion that protrudes through an aperture, hole or crack in the outer pipe. This may provide support in these weak areas.

[0042] Optionally, further comprising at least one intervening layer of material situated between the first tubular layer and the second layer. This may aid adherence of the second layer.

[0043] Optionally, the first layer and the second layer are the first and second layers of the first and second aspects.

[0044] In accordance with a fourth aspect of the present invention there is described a method of lining a pipe, wherein the method comprises the steps of; placing a first tubular layer inside the pipe; adjusting the pressure within the first tubular layer such that first tubular layer expands radially and an outer surface of the first tubular layer abuts an inner surface of the pipe; lining the inner surface of the first tubular layer with a second layer, wherein the second layer is a fluid; curing the fluid of the second layer onto the inner surface of the first tubular layer such that the second layer hardens to hold the first tubular layer in the expanded radial state; adjusting the pressure from within the first tubular layer to atmospheric pressure. This may advantageously provide a method for creating an inner pipe within a damaged outer pipe. This may enable pipes to have longer lives, and decrease the need to fully replace them.

[0045] Optionally, the method further comprises the steps of: connecting a first end of the first tubular layer to a pressure providing element, wherein the pressure proving means is an air pump; placing a first end block on a second end of the first tubular layer; providing air into the first tubular layer through the first end of the first tubular layer via the pressure providing element. This may enable a simple method for radially tensioning the first tubular layer.

[0046] Optionally, the disposing and lining of the inner surface of the first tubular layer further comprises the steps of: placing an applicator head into the first tubular layer, when the first tubular layer is in a radially tensioned state and abutting the inner surface of the pipe; spinning an element of the applicator head such that the fluid exits the applicator head and lines the inner surface of the first tubular layer. This may enable the surface of the second layer to be even.

[0047] Optionally, further comprising the step of cutting an aperture in the first tubular layer and the second layer that corresponds with the position of a connection the pipe and a second pipe. This may allow for previous connections between the outer pipe and other external pipes to be made with the new inner pipe.

[0048] Brief Description of Fiaures

[0049] Figure 1 shows a perspective view of a pipe with first tubular layer within it in a non- radially tensioned state.

[0050] Figure 2 shows a cross section of a pipe with the first tubular layer within it in a non- radially tensioned state, and with a pressure providing element connected to one end, and end blocks at both ends of the first tubular layer.

[0051] Figure 3 shows a cross section of a pipe with the first tubular layer within it in a radially tensioned state, and with a pressure providing element connected to one end, and end blocks at both ends of the first tubular layer. Figure 4 shows a cross section of a pipe with the first tubular layer within it in a radially tensioned state, and with a pressure providing element connected to one end, end blocks at both ends of the first tubular layer, and an applicator head partway through the spray lining process of the inner surface of the first tubular layer.

[0052] Figure 5 shows a cross section of a pipe with the first tubular layer within it in a radially tensioned state, and with a pressure providing element connected to one end, end blocks at both ends of the first tubular layer, and an inner cured lining of the first tubular layer.

[0053] Figure 6 shows an inner pipe formed of a first tubular layer in a radially tensioned state, and a second layer formed by the cured spray lining of the inner surface of the first tubular layer.

[0054] Figure 7 shows a herniated portion of the inner pipe.

[0055] Figure 8 shows a herniated portion of the inner pipe relative to a hole in the outer pipe.

[0056] Figure 9 shows an applicator head.

[0057] Figure 10 shows a flow diagram illustrating the steps of the method of lining a pipe.

[0058] Detailed Description of Figures

[0059] Figures 1 to 5 show a lining arrangement 1 for a pipe 3, wherein the lining arrangement 1 comprises: a first tubular layer 5 configured to be situated within the pipe 3; a pressure providing element 7; wherein the first tubular layer 5 is configured to line an inner pipe surface 9 of the pipe 3 when the first tubular layer is in a radially tensioned state; and wherein the pressure providing element 7 is configured to apply pressure to the first tubular layer 5 such that the first tubular layer 5 is stretched from a non-radially tensioned state to the radially tensioned state.

[0060] Figures 1 to 5 also show a lining arrangement 1 for a pipe 3, wherein the lining arrangement 1 comprises: a first tubular layer 5 configured to be situated within the pipe 3; and an applicator head 11 configured to spray line an inner surface 13 of the first tubular layer 5 with a fluid 15. In the embodiment seen in Figure 1, the first tubular layer 5 is seen in a collapsed and folded configuration which reflects a non-radially tensioned state of the first tubular layer. The term "non-radially tensioned state" may, in one interpretation, refer to a condition wherein the walls of the first tubular layer are not subjected to a force that is able to form or maintain a cylindrical shape of the first tubular layer. Furthermore, the first tubular layer 5 is a stretchable structure and, in the embodiment seen, is made from an airtight polymeric file or layer, for example polyurethane. The first tubular layer 5 also has a thickness generally in the range of 0.5mm to 3mm (however in some embodiments the thickness may deviate slightly from this range). For example, first tubular layers 5 constructed of polyethylene may comprise a thickness 0.15mm. In line with this, a first tubular layer 5 thickness range of 0.1mm to 3 mm may be beneficial for a large range of applications. Additionally, the first tubular layer 5 has a smaller diameter than the inner diameter of the pipe 3 when in this non-radially tensioned state. Here, diameter relates to the conventional measurement of a diameter for a cylindrical shape (the first tubular layer 5) and not a measurement of the dimensions seen in the collapsed and folded configuration seen in Figure 1 (which may nonetheless also be folded to fit within the pipe's dimensions). The first tubular layer 5 is in a non-radially tensioned state when the pressure within the central cavity of the first tubular layer 5 (or within the two ends of the first tubular layer 5) is at atmospheric pressure.

[0061] Alternative embodiments of the first tubular layer 5 may be made from other types of materials, either stretchable or non-stretchable. First tubular layers 5 made from non- stretchable materials may include structures that are able to be inflated, or radially tensioned, to a predefined and specific diameter but not beyond this specific diameter. This predefined or specific diameter may be the inner diameter of the pipe or substantially similar to the inner diameter of the pipe and may be a pre-set manufactured dimension. Such structures can still transition from a non-radially tensioned state (at atmospheric pressure) to a radially tensioned state by being pressurised to their pre-defined diameters. The first tubular layer 5 may also have an inner bonded woven or a profiled surface to interlock with the second spray applied lining fluid such that a composite lining structure is created within the pipe 3.

[0062] The first tubular layer 5 may in some embodiments further comprise a two-ply construction. A first layer may be a coating of PVC, polypropylene or polyurethane. A second layer may be a layer of felt, polyester fibre, glass reinforced fibre or a looped PE layer which is soaked in a resin, for example a cure in place (CIPP) or a UV resin. The first layer (the coating layer) may coat the second layer (the fibre layer). The first tubular layers of this construction may be particular suited for Cure-In-Place- Pipe, CIPP, uses.

[0063] The term radially tensioned may refer to a condition wherein the walls of the first tubular layer 5 are stressed, either by force or other, such that the first tubular layer 5 at least forms and maintains a cylindrical shape or leads to an expanding cylindrical structure. This described cylindrical arrangement is not limited to regularly shaped cylinders and include the accommodation for any ovality in the pipe 3.

[0064] Figure 2 shows the lining arrangement for a pipe 3 comprising the first tubular layer 5, a pressure providing element 7 and first and second end blocks 17, 19. The first and second ends shown in the Figures may in practice be interchangeable. Figure 2 still shows the first tubular layer in the non-radially tensioned state. The pressure providing element comprises an air delivery hose 7a (understood to a part of the pressure providing element) that is positioned proximal to a first end 21 of the first tubular layer 5. The first end block seen in Figure 2 is positioned such that it is at the end of the pipe that is proximal to a distal (second) end 23 of the first tubular layer 5. The second end block 19 is located such that it is at the end of the pipe that is proximal to a proximal (first) end of the first tubular layer 5 and at a second side of the air delivery hose 7a to the first tubular layer 5. The pressure providing element 7 is configured to provide air into the first tubular layer 5 within the pipe 3. More specifically, the pressure providing element 7 is configured to provide the air into the central cavity of the first tubular layer 5. In the embodiment seen in Figure 2, the air is seen to enter the pipe 3 through a portion of the pipe 3 wall. In alternative embodiments, the air may be delivered from an end of the pipe 3 (open end not shown) and wherein the pressure providing element 7 may cover the entire cavity of the pipe 3. For such embodiments, only one end block 17 located at the distal end 23 of the first tubular layer 5 may be required. Alternative embodiments may also have the end blocks positioned closer to the proximal and distal ends of the first tubular layer 5.

[0065] In Figure 2, the first and second end blocks 17, 19 are configured to minimise the air escaping from within the pipe portion that extends in between them. The end blocks 17, 19 also therefore minimise the air escaping from the first tubular layer 5 and traps a volume of air within the first tubular layer 5. This entrapment of the air within the first tubular layer 5 allows the air pressure within the first tubular layer 5 to be raised by the pressure providing element 7. This allows for the first tubular layer 5 to transition, or stretch, from a non-radially tensioned state to a radially tensioned state. Once more, the term radially tensioned may refer to a condition wherein the walls of the first tubular layer 5 are stressed, either by force or other, such that the first tubular layer 5 at least forms and maintains a cylindrical shape or leads to an expanding cylindrical structure.

[0066] The pressure provided by the pressure providing element 7 is in the range of 0.3 to 0.5 Bar and in the embodiment seen in Figure 2, the pressure providing element 7 is a compressor. In other embodiments, the pressure providing element 7 may be an air pump, or other air providing means. Also in other embodiments, the pressure provided by the pressure providing element 7 may be increased beyond this pressure range. This may be dependant on the depth of the pipe 3 and the potential of higher external ground water forces acting on the pipe. This pressure range may also be dependent on the thickness of the first tubular layers 5, particularly the wall thicknesses of the first tubular layers in different applications. In line with this, a pressure range between 0.1 Bar (for thinner walled first tubular layers) and 1 Bar (for thicker walled first tubular layers) may cover a large number of applications.

[0067] Furthermore, and although not shown, the first tubular layer 5 of Figure 2 in some embodiments may be sealed against the pipe 3 at its distal and proximal ends 23, 21. This seal can be achieved by using internal clamps (not shown) to cause the first tubular layer 5 to abut the inner pipe surface of the pipe 3 at the distal 23 and proximal 21 ends of the first tubular layer 5. In an alternative embodiment, these extreme ends of the first tubular layer 5 may be constrained to the pipe 3 by stretching the distal and proximal ends over the ends of the pipe 3. This may use flange adaptors (not shown).

[0068] Additionally, an air hole or air holes may be required in pipe 3 along the length between the proximal 21 and distal ends 23 of the first tubular layer 5 so as to allow air or any water in pipe 3 to be forced out of pipe 3 when the first tubular layer 5 is radially pressurised against pipe 3.

[0069] Other embodiments may also implement an alternative radially tensioning mechanism that does not rely on an increase in the internal pressure of the first tubular layer 5. Such alternative mechanisms may involve mechanically tensioning the first tubular layer 5 by virtue of a physical element radially stretching or tensioning the first tubular layer 5 within the pipe 3. Said element may simply abut the first tubular layer 5 from within its central cavity and apply a force onto the first tubular layer 5 such that the outer surface of the first tubular layer 5 abuts the inner surface of the pipe 3. Another alternative embodiment may comprise the first tubular layer having two states that are influenced by a physical parameter such as temperate, electric current, magnetism or the like. For example, running a current through the first tubular layer may cause the first tubular layer to enter into a radially tensioned state. Likewise, temperature may be used for a similar effect. Alternatively, shape-memory materials (such as Nitinol or the like) may be used and the first tubular layer held within a delivery sheath. As the first tubular layer is unsheathed it may then return to a radially tensioned state.

[0070] Figure 3 shows the first tubular layer 5 of Figure 2 in a now radially tensioned state. In this radially tensioned state, the first tubular layer 5 is seen to line the inner pipe surface 9 of the pipe 3. More specifically, Figure 3 shows the outer surface of the first tubular layer 5 abutting the inner pipe surface of the pipe 3. This abutment is a nonadhesive abutment and a consequence of the radially tensioned state of the first tubular layer 5 whereby the air pressure from within the central cavity of the first tubular layer 5 stretches and pushes the first tubular layer 5 against the inner pipe surface 9 of the pipe 3. The interface between the outer surface of the first tubular layer 3 and the inner pipe surface 9 of the pipe 3, as a result of this pressurised abutment, allows for the relative displacement of the two surfaces with respect to one another. As such, the first tubular layer 5 and the inner pipe surface 9 of the pipe 3 are not rigidly attached together in this embodiment. This abutment may be highly advantageous as it allows for an effective means to absorb forces acting on the pipe 3 from an exterior side and reduces the transference of said forces to the first tubular layer 5. It may also be effective absorbing any movement of the pipe 3 in the event of a pipe fracture. In this way the first tubular layer 5 may form a stronger internal lining or pipe segment within the pipe 3 that is less prone to failure.

[0071] This pressurised, or radially tensioned, abutment of the first tubular layer 5 onto the inner pipe surface 9 of the pipe 3 provides both, a means to 'hold' the first tubular layer 5 in an optimal configuration within the pipe 3 and create space within the pipe 3 (and the first tubular layer 5) for the applicator head 11 to enter the cavity of the tubular layer 5 and begin the second stage of creating a pipe 3 repair or rehabilitation (spray lining). The optimal configuration here refers to a position where the first tubular layer 5 adopts the shape and dimensions (form) of the pipe 3 and in doing so provides a platform for a pipe repair that is significantly similar to the original pipe 3. Furthermore, this pressurisation, or radial tensioning, also enables a low tolerance fit between the first tubular layer 5 and the pipe 3 so as to longitudinally constrain the first tubular layer 5 within the pipe 5. Additionally, said configuration may also provide a smooth surface onto which to effectively deposit, or apply, a liquid or fluid-to-be- cured. This may ensure an effective pipe repair. Figure 4 provides a view of an applicator head 11 partway through the process of spray lining an inner surface 13 of the first tubular layer 5 with a fluid 15. In the embodiment seen, the fluid 15 that is applied to the first tubular layer 5 in the spray lining process is a polymer comprising of two liquids. These two polymers are mixed in the applicator head 11 or within other parts of the applicator head assembly, such as a static mixer (not shown). In alternative embodiments, the applied fluid 15 may be another type of fluid or polymer and may be pre-mixed before being delivered to the applicator head 11 or not require any mixing (a fluid made from one type of substance for example). The fluid 15 (or more specifically the polymers) may in some embodiments be epoxy resins, polyurea(s), polyurethanes or a mixture made from or comprising a combination of any of these.

[0072] The first tubular layer 5 of Figure 4 is maintained in a radially tensioned state, by virtue of the pressure providing element 7, during the spray lining process. This both ensures a smooth surface for applying the fluid 15 and sufficient space within the cavity of the first tubular layer 5 to pass the applicator 11 head through it. This radially tensioned state is maintained by the pressure providing element 7 until the fluid 15 has cured onto the spray lined inner surface 13 of the first tubular layer 5. After which, the cured, or hardened fluid, forms a second layer 25 on the inner surface 13 of the tubular layer 5 which constrains the first tubular layer 5 in this radially tensioned state.

[0073] Also seen in Figure 4 is the close-up view of the applicator head 11. The applicator head comprises a spinning element, wherein the spinning element 27 is configured to spin and exert a centrifugal force onto the fluid 15 retained within the applicator head 11. This centrifugal force on the fluid 15 forces the fluid 15 to exit the applicator head 11 and line the inner surface 13 of the first tubular layer 5. This action is completed alongside the pulling of the applicator head 11 through the internal cavity of the first tubular layer 5 and along its length. This results in a length of the inner surface 13 of the tubular layer 5 to be spray lined by the fluid 15. The applicator head 11 in the embodiment seen is pulled via a pulling element 29 (may be referred to as an umbilical hose within the industry). In other embodiments however, the applicator head 11 may be pulled with a mechanical means or translated along the first tubular layer's 5 length through other means. Other embodiments may also not comprise a spinning element 27 and instead expel the fluid 15 across the entire inner circumference of the first tubular layer 5 from a rotationally stationary source or by a vortex of air process. It is noted that the applicator head 11 and the pulling element 29 may reside within the pipe 3, and at a location between the first and second end blocks, during the pressurisation stage discussed in Figures 2 and 3 such that the pressure loss that would otherwise be associated with entering the applicator head 11 into the pipe 3 is avoided. The pulling element 29 may also be pulled back through the end block 19, which may comprise a glanded portion for such exit, such that air loss is minimised during the spray lining operation as the applicator head 11 and the pulling element 29 translate through the pipe. It may also be that after completing the spray lining process the applicator head 11 resides within a portion of the pipe 3 between the proximal end 21 of the first tubular layer 5 and the end block 19, until the applied fluid 15 has cured onto the inner surface 13 of the first tubular layer 5. It may also be that the pipe 3 may further comprise means to portion off this section of the pipe 3 such that the first tubular layer 5 may remain pressurised yet the section of the pipe 3 where the applicator head 11 resides after the spray lining process may be unpressurised, or return to atmospheric pressure. Such means to portion off the pipe sections may involve elements known as knife valves.

[0074] The fluid 15 in the embodiment seen in Figure 4 is applied onto and beyond a proximal and distal end 21, 23 of the first tubular layer 5 such that the geometry of the pipe repair provides a smooth transition from the pipe 3 to the first tubular layer 5.

[0075] For embodiments that implement a mechanical stretching or tensioning means to radially tension the first tubular layer 5, a process that incrementally stretches or tensions the first tubular layer 5 at portions along its length may be utilised. For such processes, it may be that the fluid 15 is applied selectively and only to the radially tensioned portions of the first tubular layer 5 whilst other portions of the first tubular layer 5 that remain radially un-tensioned are not spray lined. For such embodiments, it may also be beneficial to implement a pushing element (not shown), as opposed to the pulling element 29, that translates an applicator head 11 from a proximal end 21 of the first tubular layer 5 to the distal end 23 of the first tubular layer 5. This may allow for sufficient space within the central cavity of the first tubular layer 5 to accommodate the applicator head 11. Furthermore, such embodiments may radially tension the first tubular layer 5 at various separate portions along the length of the first tubular layer 5, whereby the radially tensioned portions may be at the distal 23 and proximal ends 21 of the tubular layer 5 and at its centre. Whereby these tensioned portions may be spray lined prior to spray lining the intermediate portions of the first tubular layer 5 between these points.

[0076] Other embodiments may also implement other mechanical stretching or tensioning means that radially tension the first tubular layer 5 along the entire length of the first tubular layer 5. A similar spray lining process to that seen in Figure 4 may be implement for such embodiments. Alternative embodiments may also implement an entirely different mechanism to apply the fluid 15 onto the inner surface 13 of the first tubular layer 5 to that of the applicator head 11. Such alternative embodiments may seek to apply the fluid-to-be- cured onto the inner surface 13 of the first tubular layer 5 through a brush stroke or physical contact between the application element (not shown) and the inner surface 13 of the first tubular layer 5.

[0077] Figure 5 shows the pipe 3 lined with the first tubular layer 5 and with the fluid cured on the inner surface 13 of the first tubular layer 5. The cured fluid is configured to form a second layer 25 that is adhered to the first tubular layer 5. This second layer 25 may be referred to as a second tubular layer. At this point (after curing), this second layer 25 constrains the first tubular layer 5 to its radially tensioned state and does so at atmospheric pressure (i.e. without the aid of the pressure providing element 7). This allows for the maintained contact between the outer surface of the first tubular layer 5 and the inner pipe surface 9 of the pipe 3 and it does so without a pressure providing element 7. Furthermore, within this two layer lining arrangement, the first tubular layer 5 may have a greater stiffness than the second layer 25 formed by the cured fluid 15.

[0078] Figure 6 shows an internal pipe segment 30 for lining an outer pipe (not shown), wherein the internal pipe segment comprises; a first tubular layer 5; and a second layer 25; wherein the outer surface of the first tubular layer 5 is configured to abut an inner surface of the outer pipe; and wherein the second layer 25 is configured to be cured onto the inner surface of the first tubular layer.

[0079] The internal pipe segment 30 seen in Figure 6 is a rigid structure within an outer pipe (not shown). This internal pipe segment is substantially similar in size and shape to the outer pipe and resides within the outer pipe in a fixed longitudinal location due to the tight tolerance fit between the internal pipe segment and the outer pipe. It is understood that this internal pipe segment is formed by the process outlined in Figures 1-5.

[0080] Figures 7 and 8 shows a herniated portion 31 of the first tubular layer 5 and the second layer 5 protruding through a hole, or aperture 33, in the pipe 3. This herniated portion 31 may be a feature for any embodiment discussed above. The herniated portion 31 comprises a tapered profile from the portion of the first tubular layer 5 directly overlying the boundary 35 of the aperture to the centre 37 of the hernia (or herniated portion) 31, whereby the centre 37 of the hernia is the furthermost protruding portion of the hernia (or herniated portion 31). This herniated portion 31 aids the first tubular layer 5 in forming a bridge across any aperture 33 in the pipe 3. Aperture 33 here referring to any hole, pipe joint or crack too. The second layer 25 on the inner surface 13 of the first tubular 5 layer is configured to line both, the herniated portion 31 of the first tubular layer 5 and any aperture bridging portion.

[0081] Furthermore, for all the embodiments discussed above of Figures 1 to 8, there may be present one intervening layer (not shown) of material situated between the first tubular layer 5 and the second layer 25. Additionally, the spray lining or second layer 25 discussed above may comprise a plurality of layers (now shown). The number of layers may depend on the strength level intended to be achieved for the pipe lining or pipe segment. A third or more layers of the fluid may be subsequently applied and cured onto the second layer 25 to further increase the structural capability of the lining arrangement.

[0082] Figure 9 shows a close up of an applicator head 11 used in the spray lining process of the inner surface 13 of the first tubular layer 5. Other embodiments may use other means to achieve the same function, that may involve a contacting element that applies the fluid onto the first tubular layer 5. It is noted that the fluid 15 to be deposited onto the inner surface 13 of the first tubular layer 5 is delivered in liquid form and is configured to cure-in-place onto the inner surface 13 of the first tubular layer 5 to form the second layer 25. This fluid 15 in the embodiments discussed comprises two polymers that are delivered to the applicator head 11 in the exact quantities, or mix ratio, required for the spray lining process. These ratios may be a predefined requirement as per legislation and may achieve the optimal consistency of the fluid to adhere to the first tubular layer 5. Each polymer may be dispensed by a fluid metering pump and mix ratios are generally within a range from 1: 1 to 4: 1.

[0083] Furthermore, the pulling element 29 (or umbilical hose) may contain separate internal hoses (not shown) and in particular may contain two internal hoses. Each of these internal hoses may deliver one of the two polymers needed for the spray lining process. This arrangement may aid the pulling element 29 to smoothly be translate the applicator head 11 along the first tubular layer 5 whilst it is spray lining the inner surface of the first tubular layer 5.

[0084] Figure 10 shows a method 40 of lining a pipe. A first step 41 in such method is placing a first tubular layer inside the pipe. A second step 42 then involves adjusting the pressure within the first tubular layer such that the first tubular layer expands radially. This radial expansion then results in the outer surface of the first tubular layer abutting an inner pipe surface of the pipe. A third step 43 then relates to lining the inner surface of the first tubular layer with a second layer, wherein the second layer is a fluid that has been depositing onto the inner surface of the first tubular layer. A fourth step 44 then involves curing the fluid of the second layer onto the inner surface of the first tubular layer such that the second layer hardens to hold the first tubular layer in the expanded radial state. A fifth step 45 then relates to adjusting the pressure from within the first tubular layer back to atmospheric pressure, or the normal pressure within the pipe. Third and subsequent layers of the fluid, or a different fluid with other physical properties or differing chemical resistance may then be applied to the hardened second layer to further increase the structural capability of the composite lining.

[0085] The general steps outlined above are further supported by steps related to establishing the pressure required for the radial expansion of the first tubular layer. These steps relate to connecting a first end of the first tubular layer to a pressure providing element, wherein the pressure proving means is an air pump. This may alternatively involve providing air proximal to a first end of the first tubular layer through the pressure providing element and without forming a physical connection between the first tubular layer and the pressure providing element. A second step of such pressure establishing arrangement may involve placing a first end block on the end of the pipe that is proximal to a second end of the first tubular layer. A second end block may also be placed onto a second side of the pressure providing element to the first tubular element such that a control volume of air may be trapped between the two end blocks and wherein the tubular layer may be situated within this control volume. This arrangement will then provide air into the first tubular layer and result in radial expansion or tensioning of the first tubular layer.

[0086] Furthermore, intermediate steps related to spray lining the inner surface of the first tubular layer may further support the general steps outlined above. A first of these steps may relate to placing an applicator head into the first tubular layer, when the first tubular layer is in a radially tensioned state and abutting the inner pipe surface of the pipe (after method step 2). The applicator head is then spun, or an element of the applicator element is then spun, such that the fluid exits the applicator head and lines the inner surface of the first tubular layer.

[0087] A further step may be relevant at an intersection point of a first pipe and second pipe. This further step may take place after the first tubular layer and second tubular layer are formed and may involve cutting an aperture in the first tubular layer and the second layer. This aperture shall correspond with the position of a connection between the two intersecting pipes. The above embodiments are to be understood as illustrative examples. Further embodiments are also envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments.

[0088] Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

[0089] In some examples, one or more memory elements can store data and / or program instructions used to perform the methods described herein. This may particularly relate to a processor used to determine the steps to be performed, and when each step has been completed. For example, the processor may determine the speed at which the applicator head is moved through the pipe, and / or when the lining is complete, and / or the pressure within the pipe and whether this pressure is being maintained. Embodiments of the disclosure provide tangible, non-transitory storage media comprising program instructions operable to program a processor to said method.

[0090] The processor / controller of such method of use (and any of the methods, activities or instructions outlined herein) may be implemented with fixed logic such as assemblies of logic gates or programmable logic such as software and / or computer program instructions executed by a processor. Other kinds of programmable logic include programmable processors, programmable digital logic (e.g. a field programmable gate array (FPGA), an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM), an application specific integrated circuit (ASIC) or any other kind of digital logic, software, code, electronic instructions, flash memory, optical disks, CD-ROMs, DVD ROMs, magnetic or optical cards, other types of machine-readable mediums suitable for storing electronic instructions, or any suitable combination thereof.

Claims

Claims1. A lining arrangement for a pipe, wherein the lining arrangement comprises: a first tubular layer configured to be situated within the pipe; a pressure providing element; wherein the first tubular layer is configured to line an inner pipe surface of the pipe when the first tubular layer is in a radially tensioned state; and wherein the pressure providing element is configured to apply pressure to the first tubular layer such that the first tubular layer is stretched from a non-radially tensioned state to the radially tensioned state.

2. The lining arrangement of claim 1, wherein the lining arrangement further comprises an applicator head configured to spray line an inner surface of the first tubular layer with a fluid.

3. A lining arrangement for a pipe, wherein the lining arrangement comprises: a first tubular layer configured to be situated within the pipe; and an applicator head configured to spray line an inner surface of the first tubular layer with a fluid.

4. The lining arrangement of claim 3, further comprising a pressure providing element; wherein the first tubular layer is configured to line an inner pipe surface of the pipe when the first tubular layer is in a radially tensioned state; and wherein the pressure providing element is configured to apply pressure to the first tubular layer such that the first tubular layer is stretched from a non-radially tensioned state to the radially tensioned state.

5. The lining arrangement of any of claims 1, 2 or 4, wherein the pressure providing element is positioned at a first end of the pipe or at a first end of the first tubular layer within the pipe, and is configured to provide air into the first tubular layer.

6. The lining arrangement of any of claims 1, 2, 4 or 5, further comprising an end block positioned at a second end of the pipe or at a second end of the first tubular layer within the pipe, and is configured to minimise air escaping from the first tubular layer, optionally wherein the end block traps a volume of air within the first tubular layer and allows the air pressure within the first tubular layer to be raised by the pressure providing element, further optionally wherein the lining arrangement further comprises a second end block, and when dependant on claim 5, wherein the second end block is positioned on a second side of the pressure providing element to the first tubular layer.

7. The lining arrangement of any of claims 1, 2, 4, 5, or 6, wherein the pressure provided by the pressure providing element is in the pressure range of 0.3 to 0.5 Bar.

8. The lining arrangement of any of claims 1, 2, 4, 5, 6, or 7, wherein the pressure providing element is a compressor, pressurised gas cylinder or air pump.

9. The lining arrangement of any of claims 2, 4, 5, 6, 7, or 8, wherein the pressure providing element is configured to provide a pressure to maintain the first tubular layer in the radially tensioned state until the fluid that has been spray lined on the inner surface of the first tubular layer is hardened or cured.

10. The lining arrangement of any preceding claim when dependent on one of claims 2 or 3, wherein the applicator head comprises a spinning element, wherein the spinning element is configured to spin such that the centrifugal force on the fluid forces the fluid to exit the applicator head and line the inner surface of the first tubular layer.

11. The lining arrangement of any preceding claim when dependent on one of claims 2 or 3, wherein the lining arrangement further comprises a pulling element configured to pull the applicator head through the first tubular layer such that a length of the inner surface of the first tubular layer is lined by the fluid.

12. The lining arrangement of any preceding claim when dependent on one of claims 2 or 3, wherein once cured the fluid is configured to form a second layer, optionally wherein the second layer is adhered to the inner surface of the first tubular layer, further optionally wherein the second layer is configured to form a second tubular layer, optionally wherein once cured the second layer is configured to constrain the first tubular layer and so maintain the radial tension within the first layer, and / or optionally wherein the second layer is configured to cure-in-place onto the inner surface of the first layer.

13. The lining arrangement of any preceding claim when dependent on one of claims 2 or 3, wherein the fluid comprises a mixture of two liquid polymers, optionally wherein the applicator head is configured to mix the two liquid polymers.

14. The lining arrangement of any preceding claim, wherein an outer surface of the first tubular layer is configured to abut an inner pipe surface of the pipe, optionally wherein the abutment is configured such that a portion of the first tubular layer is displaceable relative to the inner pipe surface of the pipe that the first tubular layeris abutting, and / or optionally wherein the abutment between the first tubular layer and the inner pipe surface of the pipe is characterised as a non-adhesive abutment.

15. The lining arrangement of any preceding claim, wherein the first tubular layer is a stretchable structure, optionally wherein the first tubular layer is configured to be stretched from a non-radially tensioned state to a radially tensioned state, optionally when dependent on claim 3 but not dependent on claim 4, wherein the first layer is radially tensioned with mechanical means, or wherein it is radially stretched with mechanical means.

16. The lining arrangement of any preceding claim, wherein the first tubular layer has a smaller diameter than the inner diameter of the pipe when the first tubular layer is in an un-tensioned state.

17. The lining arrangement of any preceding claim, wherein the first tubular layer is made from an airtight polymeric file or layer, for example polyurethane; and / or wherein first tubular layer has a thickness between 0.5mm and 3mm.

18. The lining arrangement of any preceding claim, when dependant on claim 12, wherein the first tubular layer has a greater stiffness than the second layer.

19. The lining arrangement of any preceding claim, wherein the first tubular layer is configured to herniate through an aperture, hole or crack in the pipe surface, optionally wherein the profile of the herniation is tapered from the portion of the first tubular layer directly overlying the boundary of the aperture, hole or crack of the pipe surface to the centre of the hernia.

20. The lining arrangement of any preceding claim, when dependant on claim 12, wherein the first tubular layer is configured to form a bridge across an aperture, pipe joint, hole or crack in the inner pipe surface, and wherein the second layer is configured to line the bridging portion.

21. An internal pipe segment for lining an outer pipe, wherein the internal pipe segment comprises; a first tubular layer; and a second layer; wherein the outer surface of the first tubular layer is configured to abut an inner pipe surface of the outer pipe; andwherein the second layer is configured to be cured onto the inner surface of the first tubular layer.

22. The internal pipe segment of claim 21, wherein the internal pipe segment forms a rigid structure within the outer pipe; and / or wherein the pipe segment comprises a herniated portion that protrudes through an aperture, hole or crack in the outer pipe; and / or further comprising at least one intervening layer of material situated between the first tubular layer and the second layer.

23. The internal pipe segment of any of claims 21 to 22, wherein the first layer and the second layer are the first and second layers of claims 1 to 20.

24. A method of lining a pipe, wherein the method comprises the steps of; placing a first tubular layer inside the pipe; adjusting the pressure within the first tubular layer such that first tubular layer expands radially and an outer surface of the first tubular layer abuts an inner pipe surface of the pipe; lining the inner surface of the first tubular layer with a second layer, wherein the second layer is a fluid; curing the fluid of the second layer onto the inner surface of the first tubular layer such that the second layer hardens to hold the first tubular layer in the expanded radial state; adjusting the pressure from within the first tubular layer to atmospheric pressure.

25. The method of claim 24, wherein the method further comprises the steps of: connecting a first end of the first tubular layer to a pressure providing element, wherein the pressure proving means is an air pump; placing a first end block on a second end of the first tubular layer; providing air into the first tubular layer through the first end of the first tubular layer via the pressure providing element; and / or wherein the disposing and lining of the inner surface of the first tubular layer further comprises the steps of:placing an applicator head into the first tubular layer, when the first tubular layer is in a radially tensioned state and abutting the inner pipe surface of the pipe; spinning an element of the applicator head such that the fluid exits the applicator head and lines the inner surface of the first tubular layer; and / or further comprising the step of cutting an aperture in the first tubular layer and the second layer that corresponds with the position of a connection the pipe and a second pipe.