CN106985427B

CN106985427B - Pipe structure

Info

Publication number: CN106985427B
Application number: CN201610811497.4A
Authority: CN
Inventors: 尼尔·德里克·布雷·格拉哈姆
Original assignee: LONG PIPES Pty Ltd
Current assignee: LONG PIPES Pty Ltd
Priority date: 2011-10-31
Filing date: 2011-10-31
Publication date: 2020-07-28
Anticipated expiration: 2031-10-31
Also published as: NZ702945A; IL232242A; KR101948367B1; CN104081098A; NZ623931A; NZ721935A; KR20140072917A; HK1201574A1; MX2014005177A; CN106985427A; IL232242A0; JP2014532570A; CN104081098B; MX352503B; JP6009573B2

Abstract

An elongated hollow structure, such as a pipe (10), and a method for constructing such an elongated hollow structure. The tube (10) comprises a radially inner portion (11) and a radially outer portion (13), the two portions (11, 13) being merged together to provide a complete tubular wall structure. The method comprises the following steps: the radially inner portion (11) is provided in the form of an inner tube (21), and the radially outer portion (13) is assembled around the inner tube (21). The outer portion (13) comprises an outer tube (30) of fibre-reinforced composite construction, which is surrounded by a flexible outer shell (31). The inner tube (21) is expanded to provide the form and shape to the outer portion (13).

Description

Pipe structure

This application is a divisional application of PCT patent application with application number 201180074533.9, application date 2011, 10/31, and entering the chinese national phase at 2014, 4/29.

Technical Field

The present invention relates to a combined structure of elongated hollow structures, particularly including tubular structures.

Although the invention has been designed with particular reference to the construction of tubular structures in the form of tubes, it can also be applied to the construction of other elongate hollow elements, including: tubular elements, such as conduits and pipes; tubular structural elements such as shafts, beams and cylinders; and other tubular elements of modular construction.

Background

The following description of the background art is intended only to facilitate an understanding of the present invention. The description is not to be taken or an admission that any of the material referred to was or was common general knowledge as at the priority date of the application.

It is known to use fibre reinforced plastic composites to form the tube. Typically, such tubes are constructed by a process in which rovings of filaments of fibrous material (e.g., glass fibers) are impregnated with a thermosetting resin or thermoplastic composition and wound back and forth on a mandrel to form a composite-constructed tube wall structure.

Furthermore, it has also been attempted to produce continuous tubes by pultrusion, which involves working the tube by drawing a moist body of reinforcing fibres through a heated die, and then winding the tube on a reel. Pipes formed in this manner are typically limited to a length of about 1km and a diameter of about 100 mm.

Typically, such pipes are required to withstand both hoop and axial stresses, and the configuration may be a balance between the required hoop and axial stress bearing properties of the pipe. Hoop strength is optimized by winding the filaments at an angle of about 90 ° to the tube axis. The axial strength is optimized by winding the reinforcing filaments at an angle close to the axis of the tube.

The length of the tube constructed in this manner refers to the length of the mandrel or roller that transports the tube. Therefore, this construction process does not facilitate the manufacture of long tubes that form a transport network for liquids and gases; i.e. those much longer than the available mandrels and those constituting the length of the continuous extension line between two remote stations, possibly hundreds to thousands of kilometres apart.

If there were a way to form a pipeline from a tube constructed on a continuous basis, that is, without being formed from a series of connected tube sections, these connections could constitute an integral weak area of the pipeline structure.

The present invention has been made to solve the problems and problems occurring in the prior art.

Disclosure of Invention

According to a first aspect of the present invention there is provided a method of constructing an elongate hollow structure comprising a radially inner portion and a radially outer portion, the two portions being merged together to provide a complete tubular wall structure, the method comprising: providing a radially inner portion; assembling a radially outer portion around a radially inner portion; and expanding the interior; wherein the outer portion comprises an outer tube of a fibre-reinforced composite construction surrounded by a flexible outer shell.

Preferably, the outer tube of the fiber-reinforced composite construction includes a reinforcement and an adhesive.

The reinforcement includes one or more layers of reinforcing fabric. Preferably, each layer is configured as a tubular layer arranged around the radially inner portion. Typically a plurality of tubular layers are disposed around each other and also around the inner pipe.

The reinforcing fabric may comprise a reinforcing fabric comprising reinforcing fibers having the characteristic of a tetraxial fiber orientation. The reinforcing fibers comprise glass fibers. The tetraaxial fiber orientation provides the necessary hoop and axial stress bearing characteristics for the tubular structure.

Preferably, the adhesive comprises a curable plastic, such as a resin adhesive, which is commonly referred to as a resin. The adhesive sets into a resin matrix for bonding the reinforcing fabric layers together and the reinforcement to the interior to provide the completed tubular wall structure. The resin matrix can also bond the stiffener to the housing.

Preferably, the inner portion comprises an inner tube comprising an inner liner to one face of which is bonded a fabric layer, wherein the adhesive impregnating the reinforcing fibres also impregnates the fabric layer to bond the outer portion and the inner portion together.

Preferably, the outer skin comprises an outer layer and a fabric layer bonded to one face of the outer layer, the arrangement being such that the fabric layer is opposite the reinforcement. With this arrangement, the fabric layer of the housing can provide a ventilation layer for air circulation.

Preferably, the flexible outer shell is adapted to resist radial expansion of the reinforcing element, thereby subjecting the reinforcing element to radial compression. With this arrangement, the stiffener is confined in the space between the expanded interior and the flexible outer shell. The radially expanded inner portion cooperates with the flexible sheath to constrain the reinforcement, causing the volume of the space in which the reinforcement is located to gradually decrease. This forces the adhesive in the stiffener to completely soak into the stiffener; that is, the reinforcing fabric layer becomes completely "wet out". In particular, compressive forces are provided to the reinforcement and the adhesive is effectively pumped through the reinforcement fabric to distribute the adhesive into the space in a controlled and limited manner.

Furthermore, the gradual reduction in the volume of the space in which the reinforcement is located allows air to be expelled from the space, which can improve the impregnation effect of the adhesive in the reinforcement.

The outer shell and the respective reinforcing fabric tubes facilitate the evacuation of air. The outer shell and each tubular layer of reinforcing fabric are configured to facilitate the egress of air, for example, the outer shell and each tubular layer of reinforcing fabric include vent holes spaced along their respective lengths to facilitate the egress of air. In addition, or alternatively, the fabric layer of the outer shell providing the ventilation layer also facilitates the release of air, typically up and along the device to the release or vent.

The flexible outer shell has some elasticity so as to resist, at least to some extent, radial expansion of the tubular layer of reinforcing fabric. However, the flexible outer shell is less elastic than the inner tube. In this manner, the flexible outer shell is able to cushion the initial stages of radial expansion of the tubular layer of reinforcing fabric. In particular, it is desirable that the flexible enclosure have some elasticity. The flexible outer shell has some elasticity for improved control over the rate at which the adhesive gradually wets the stiffener.

According to a second aspect of the present invention there is provided a method of constructing an elongate hollow structure, the structure comprising a radially inner portion and a radially outer portion, the two portions being merged together to provide a complete tubular wall structure, the method comprising: providing a radially inner portion comprising an inner tube comprising an inner liner with a fabric layer bonded to one face of the inner liner; assembling a radially outer portion around a radially inner portion; and expanding the interior; wherein the outer portion comprises an outer tube constructed of a fibre reinforced composite surrounded by a flexible outer shell, wherein the inner portion comprises an inner tube comprising an inner lining to one face of which a fabric layer is bonded, a resin adhesive penetrating the outer tube also penetrating the fabric layer to bond the outer and inner portions together.

According to a third aspect of the present invention there is provided a method of constructing an elongate hollow structure, the method comprising forming a flexible tubular wall around a central portion, expanding the central portion to cause the tubular wall structure to assume a specified cross-sectional profile, and subjecting the tubular wall structure to a hardening, curing or other solidification process.

The central portion comprises a portion of the wall structure.

The flexible wall structure comprises a fibre-reinforced plastic composite material.

The flexible wall structure may further comprise a curable plastic, such as a resin adhesive. Typically, the curable plastic comprises a curable resin.

The fiber-reinforced plastic composite includes a reinforcement configured as a fabric containing reinforcement fibers.

Preferably, the reinforcing fabric has a tetraxial fiber orientation. The tetraaxial fiber orientation provides for commutation and axial stress bearing properties.

The flexible tubular wall structure further comprises a flexible outer shell surrounding the fibre-reinforced plastic composite material.

The expandable central portion includes an inner tube having an expandable bladder capable of expanding the flexible tubular wall structure prior to hardening, curing or other solidification of the tubular wall structure.

Preferably, the inner tube is bonded to and forms part of the tubular wall structure.

The continuous movement and expansion of the flexible tubular wall structure pre-stresses and aligns the fibers within the reinforcing fabric, thereby improving hoop stress bearing properties throughout the length of the elongated hollow structure during construction.

Preferably, the reinforcing fabric is also axially (linearly) pre-stressed to improve tensile load carrying properties.

The central portion may be configured as a bladder.

The bladder may be inflated with a fluid medium, such as air or water.

Preferably, the bladder is resiliently inflatable.

In one version, the tubular structure has a particular length. The tubular structure may, for example, comprise a tubular element, such as a tube formed into a particular length.

In another approach, the tubular structure is gradually formed to any desired length. The tubular structure, for example, may comprise a tubular element, such as a continuously formed tube, until the desired length is obtained. In this regard, the tubing may be lengths that constitute a continuous tube that provides a line extending between two remote locations.

In contrast to prior art solutions, where the pipeline extending between two remote locations generally comprises a plurality of pipe sections connected to each other, the pipe according to the first aspect of the invention allows the pipeline to be formed from one continuous pipe.

According to a fourth aspect of the present invention there is provided a method of constructing an elongate hollow structure, the method comprising forming a flexible tubular wall structure having an interior, expanding the interior of the flexible tubular wall structure to provide a form and shape thereto; the flexible wall structure is hardened, cured or otherwise cured to provide the tubular element.

The flexible wall structure comprises a fibre reinforced plastic composite material which is curable to provide the tubular element.

The flexible wall structure further comprises a flexible outer shell surrounding the fibre-reinforced plastic composite material.

In some cases, the fiber-reinforced plastic composite is cured to a rigid state. In some other applications, the fiber-reinforced plastic composite is cured to a flexible state.

The tubular wall structure includes a liner having an inner surface that is impermeable to fluids. The inner surface is defined by a high-gloss surface, such as a polyurethane layer.

According to a fifth aspect of the present invention there is provided a method of constructing a pipe, the method comprising forming a flexible tubular wall structure comprising a fibre-reinforced plastic composite material, expanding the interior of the flexible tubular wall structure to provide it with a form and shape; the flexible wall structure is hardened, cured or otherwise cured to provide the tube.

The pipe is constructed on a continuous basis and is progressively installed in place before the flexible wall structure is cured so that the flexible tubular wall is cured once in the installed position of the pipe.

According to a sixth aspect of the present invention there is provided a method for constructing a pipe on a continuous basis, the method comprising forming a flexible tubular wall structure comprising a fibre-reinforced plastic composite material, expanding the interior of the flexible tubular wall structure to provide it with a form and shape; the flexible wall structure is cured to provide a tube.

In a method according to a sixth embodiment, the flexible wall structure comprises an inner portion and an outer portion, wherein the method further comprises forming the inner portion to define an inner tube, and forming an outer tube of fibre-reinforced composite construction around the inner tube to define the outer portion.

Forming the outer tube using one or more layers of reinforcing fabric, wherein the method further comprises configuring each layer as a tubular layer disposed about the inner tube, infiltrating the tubular layer with a resin binder, expanding the inner tube to provide a form and shape thereto, and curing the resin binder to harden the tubular wall structure.

A flexible outer shell is mounted around the tubular layer of reinforcing fabric to contain a resin binder.

The flexible enclosure may be formed of any suitable material, including, for example, polyethylene.

More specifically, the flexible cover includes a polyethylene outer layer and a fabric layer bonded to one side of the outer layer, the construction being such that the fabric layer is opposite the reinforcement, as described above.

The housing is held in place and ultimately forms an integral part of the tubular structure, or is removable after its purpose is completed.

The outer face of the outer layer of the outer shell is configured to be bonded to an enclosing protective sheath, such as a concrete shell. This includes surface roughness or shaping, such as tufts (tufts) on the outside of the outer layer of the housing.

The inner tube includes an inner liner having a fabric layer bonded to one side thereof, and a resin adhesive impregnated into the reinforcing fabric also impregnated into the fabric layer to bond the outer portion and the inner portion together.

The pipe is constructed on a mobile installation apparatus, which is constructed as a vehicle, which is movable relative to the installation site, so that the continuously formed pipe is transferred stepwise to the installation site.

According to a seventh aspect of the invention there is provided a method for constructing a pipe in a flexible state, placing the pipe at an installation site, allowing the flexible pipe to be transformed into a rigid state at the installation site.

The installation site may comprise a trench into which the pipe is gradually placed in a flexible state. The pipe is placed directly into the trench or is placed along the sides of the trench and then installed step by step into the trench. The trench has a sand foundation or other material foundation forming a curved drop upon which the pipe rests for support.

The pipe is mounted on a mobile mounting device which moves relative to the installation site, arranging the pipe in a flexible state.

According to an eighth aspect of the present invention there is provided an elongate hollow structure constructed according to the method of the first, second, third or fourth aspects of the present invention.

According to a ninth aspect of the present invention there is provided a pipe constructed in accordance with the method of the third, sixth or seventh aspects of the present invention.

According to a tenth aspect of the present invention there is provided an elongate hollow structure of composite construction comprising a radially inner portion and a radially outer portion, wherein the two portions are brought together to provide a complete tubular wall structure.

The outer tube is configured as a fiber-reinforced composite. More specifically, the outer portion includes a reinforcement member impregnated in a resin adhesive.

The outer portion further comprises a flexible outer shell surrounding the outer tube.

The reinforcement includes one or more layers of reinforcing fabric, each layer configured to arrange the tube around the interior. The reinforcement may include a plurality of layers, each configured as a respective tube disposed about one another.

The reinforcing fabric includes a reinforcing fabric comprising reinforcing fibers having a tetraxial fiber orientation characteristic. The tetraxial fiber orientation provides the necessary hoop and axial stress bearing properties for the tubular structure.

The inner portion includes an inner liner with a fabric layer bonded to one side of the inner liner. The other side of the liner defines the inner surface of the tubular structure.

The resin adhesive impregnated into the reinforcing fabric is also impregnated into the fabric layer bonded to the inner liner to bond the outer portion and the inner portion together.

Drawings

The invention will be better understood by reference to the following description of various specific embodiments illustrated in the accompanying drawings, in which:

FIG. 1 is a schematic view of a tube according to a first embodiment under a manufacturing process;

FIG. 2 is a schematic cross-sectional view of the tube shown in FIG. 1;

FIG. 3 is a fragmentary side view of a length of tubing;

FIG. 4 is a schematic cross-sectional view of the interior of a tube;

FIG. 5 is a schematic illustration of a reinforcing fabric used in a tube outer configuration incorporating reinforcing fibers having a tetraxial fiber orientation;

FIG. 6 is a schematic cross-sectional view of a tubular layer of reinforcing fabric formed from the reinforcing fabric shown in FIG. 5 and used in a configuration external to the tube, the tubular layer shown in a partially assembled state;

FIG. 7 is a view similar to FIG. 6, except that the tubular layers are in an assembled state;

FIG. 8 is a schematic cross-sectional view of an assembled tubular structure from which a pipe according to the first embodiment is constructed, the tubular structure being shown in a radially expanded condition;

FIG. 9 is a view similar to FIG. 8, except showing preparation for evacuation of air from the space within the assembled tubular structure;

FIG. 10 is a view similar to FIG. 8, except the tubular structure is shown in a collapsed (non-expanded) condition;

FIG. 11 is a schematic cross-sectional view of an inner tube forming a portion of an assembled tubular structure, the inner tube shown collapsed to a flattened condition;

FIG. 12 is a schematic cross-sectional view of an assembled tubular structure from which a tube according to the first embodiment is constructed, the tubular structure being shown with an inner tube folded in a different manner;

FIG. 13 is a schematic cross-sectional view of an inner tube forming part of the assembled tubular structure shown in FIG. 12, the inner tube shown in a collapsed state;

FIG. 14 is a view similar to FIG. 13, except that the inner tube is shown in a partially flattened condition;

FIG. 15 is a view similar to FIG. 13, except that the inner tube is shown in a fully flattened condition;

FIG. 16 is a perspective schematic view of an assembly system for assembling the tubular layers of FIG. 7;

FIG. 17 is a schematic perspective view of a guide system for progressively moving the strip of reinforcing fabric shown in FIG. 5 from a first (flat) condition to a second (tubular) condition;

FIG. 18 is a view of the connections used to secure the overlapping edges of the reinforcing fabric strip together to establish a hold of the fabric strip in the second (tubular) state;

FIG. 19 is a schematic view of an assembly line for tubes, in two parts, FIGS. 19A and 19B;

FIG. 20 is a schematic cross-sectional view of an end of the tube during manufacture with an end fitting mounted thereto;

FIG. 21 is a schematic side view of the other end of the tube during manufacture of the tube, with an end fitting mounted to the end;

FIG. 22 is a schematic cross-sectional view of the end of the tube of FIG. 21, further having a corresponding profile forming system;

FIG. 23 is a schematic view of an assembly line for tubes according to a second embodiment, in two parts, FIGS. 23A and 23B;

FIG. 24 is a fragmentary view of a portion of the assembly line of FIG. 23;

FIG. 25 is a cross-sectional view taken along line 25-25 of FIG. 23B;

FIG. 26 is a cross-sectional view taken along line 26-26 of FIG. 23B;

FIG. 27 is a cross-sectional view taken along line 27-27 of FIG. 23B;

FIG. 28 is a cross-sectional view taken along line 28-28 of FIG. 23B;

FIG. 29 is a cross-sectional view taken along line 29-29 of FIG. 23B;

FIG. 30 is a cross-sectional view taken along line 30-30 of FIG. 23B;

FIG. 31 is a cross-sectional view taken along line 31-31 of FIG. 23B;

FIG. 32 is a schematic view of an assembly line of tubes according to a third embodiment;

FIG. 33 is a schematic view of a portion of the assembly line of FIG. 32 showing the sets of elements used to extrude the assembled tube structure and the housing surrounding them;

FIG. 34 is a partial fragmentary view of the assembly line of FIG. 32;

FIG. 35 is a cross-sectional view taken along line 35-35 of FIG. 34;

FIG. 36 is a cross-sectional view taken along line 36-36 of FIG. 34;

FIG. 37 is a cross-sectional view taken along line 37-37 of FIG. 34;

FIG. 38 is a cross-sectional view taken along line 38-38 of FIG. 34;

FIG. 39 is a cross-sectional view taken along line 39-39 of FIG. 34;

FIG. 40 is a cross-sectional view taken along line 40-40 of FIG. 34;

FIG. 41 is a schematic cross-sectional view of an assembled tube structure and casing therearound, showing near complete immersion in a resin binder;

FIG. 42 is a view similar to FIG. 41 but showing full immersion in the resin binder;

FIG. 43 is a fragmentary cross-sectional view of the structure shown in FIG. 39;

FIG. 44 is a schematic view of a portion of an assembly line for tubes according to a fourth embodiment;

FIG. 45 is a schematic view of a portion of an assembly line for tubes according to a fifth embodiment;

FIG. 46 is a schematic perspective view of a device employed in the assembly line of FIG. 45, the device being configured to facilitate relatively rapid wetting of a reinforcement member used in the manufacture of the tube;

FIG. 47 is a lift view of a roller array used in the apparatus of FIG. 46;

FIG. 48 is a fragmentary schematic view depicting the assembled tubular structure during manufacture of a tube subjected to an operation similar to a peristaltic pressing action by the apparatus of FIG. 46;

FIG. 49 is a fragmentary side elevation view depicting a segment of a tube according to a sixth embodiment, the segment being configured as a straight segment;

FIG. 50 is a fragmentary side elevation view depicting another segment of a tube according to a sixth embodiment, the segment being configured as a curved segment;

FIG. 51 is a fragmentary side elevation view depicting another segment of a tube according to the sixth embodiment, the segment being configured as another curved segment;

FIG. 52 is a fragmentary side view depicting another segment of the tube shown in FIG. 51 prior to being bent to form the another bent segment; and

FIG. 53 is a schematic view of a portion of an assembly line for tubes according to a seventh embodiment.

Detailed Description

Referring to fig. 1-22, a first embodiment of the present invention is directed to an elongated hollow structure configured in the form of a tubular element, such as a tube 10, and a method of constructing the tube on a continuous basis.

The tube 10 is of modular construction comprising a radially inner portion 11 and a radially outer portion 13, the two

portions

11 and 13 being brought together to provide a complete tubular wall structure. In the construction, the outer portion 13 is enclosed in a protective sheath 14 comprising a hardenable composition 16, such as a cement or concrete contained in an outermost surface layer 18, which may be any suitable material, such as geotextile. The protective sleeve 14 serves to provide protection to the pipe 10 against compressive loads that the pipe may encounter once installed.

The inner portion 11 comprises an inner lining 15 to one face of which a layer 17 of resin absorbent material is bonded. The other side of the inner liner 15 defines an inner surface 19 of the tube 10. Typically, inner liner 15 exhibits a high smooth surface at inner surface 19. For example, inner liner 15 may comprise polyurethane, polyethylene, or any other resiliently flexible material that is also preferably impermeable to air and may also be compatible with the fluid being transported within tube 10. The resin absorption layer 17 may, for example, comprise felt or cotton tow.

As shown in fig. 4, the inner portion 11 is configured as an inner tube 21 formed from longitudinal strips 23 having longitudinal side edges 25. The strip 23 is longitudinally wound into a tubular configuration to provide the inner tube 21, with the longitudinal edges 25 in abutting relationship providing a butt joint 26. An inner connecting strip 27 is applied to the inside of the inner tube 21 and an outer connecting strip 28 is applied to the outside of the inner tube 21, the two connecting

strips

27 and 28 spanning the butt joint 26 to provide a continuous fluid seal between the abutting longitudinal side edges 25. In fig. 4, the connecting

strips

27, 28 are shown spaced from the butt joint 26 for clarity reasons, but in actual use they are actually in contact with the butt joint.

The inner tube 21 defines an inflatable bladder 24 having an inflation lumen 29, the purpose of which will be explained later.

The outer part 13 is configured as an outer tube 30 of a fibre-reinforced composite structure surrounded by a flexible outer shell 31. More specifically, the outer tube 30 includes a reinforcement 32 impregnated into a resin binder. A flexible sheath 31 is mounted around the tube 30 to contain the resin adhesive, as will be described in detail later. The flexible enclosure 31 may be formed of any suitable material, including, for example, polyethylene. The housing 31 remains in place and ultimately forms an integral part of the tube 10 or may be removed after its purpose is accomplished.

The outer skin 31 comprises an outer layer of polyethylene and a fibre layer bonded to one face thereof, the arrangement being such that the fibre layer faces the reinforcement 32. The fibrous layer provides a breather layer and is ultimately impregnated with a resin binder for integration of the structure.

The resin material providing the resin binder may be of any suitable type; one particularly suitable resin material includes thermosetting resins, such as epoxy vinyl ester or other suitable resins, and thermoplastic resin systems.

The reinforcement 32 includes one or more layers 33 (shown in fig. 5) of reinforcing fabric 34, each of which is configured as a tubular layer 35 (shown in fig. 7) disposed about the inner tube 21. In this embodiment, there are a plurality of layers 33 configured as respective tubular layers 35 arranged next to each other (and thus also arranged around the inner tube 21 as previously described). Adjacent fibrous layers 33 may be bonded together in any suitable manner, such as by thermal welding, chemical bonding, and/or mechanical fastening, such as sewing or stapling.

The reinforcing fabric 34 comprises a reinforcing fabric incorporating reinforcing fibers having the characteristic of a tetraxial fiber orientation, as shown in FIG. 5. The reinforcing fibers include axial fibers 36a (at an angle close to the tube axis, as indicated by line 37 in fig. 3), transverse fibers (at an angle of about 90 degrees to the tube axis), and oblique fibers (at an angle of about 45 degrees to the tube axis). The reinforcing fibers may include glass fibers. The tetraxial fiber orientation provides the necessary hoop and axial stress bearing properties to the pipe.

Each tubular layer 35 of reinforcing fibres consists of a strip 41 of reinforcing fibre material having longitudinal edges 43 which are brought together at a joint 44 in an overlapping manner with each other to form the tubular layer 35. The overlapping edges 43 are fitted together in any suitable manner to ensure the tubular formation. In this embodiment, the overlapping edges 43 are joined together by a thermal welding technique using a hot melt adhesive. In fig. 6, the overlapping edges 43 are shown spaced apart for clarity, but in practice they actually contact each other to provide a joint 44, as shown in fig. 7. The structural integrity of joint 44 is then achieved by infiltrating reinforcing fabric 34 with a resin binder from which tubular layer 35 is formed. In particular, the resin adhesive penetrates the overlapping edges 43 and bonds them together to supplement and replace the initial bond established by the hot melt adhesive.

The individual tubular layers 35 are oriented such that the individual joints 44 are offset from one another as shown in fig. 8. In the construction shown in the drawings, the tubular layers 35 are oriented such that the respective joints 44 are disposed towards the underside 46 of the pipe 10 under construction. This is highly advantageous because the underside 46 is an area where the resin adhesive is likely to be sufficient to improve adhesion between the overlapping edges 43 at each joint 44.

The resin adhesive that penetrates reinforcing fabric 34 also penetrates felt layer 17 on liner 15 to integrate outer portion 13 with inner portion 11.

After the tubular layers 35 of reinforcing fabric are disposed adjacent to each other and thus also adjacent to the inner tube 21 as previously described, the tubular layers 35 are impregnated with a resin adhesive. In the alternative, the tubular layers of reinforcing fabric 35 are impregnated with a resin binder after each tubular layer of reinforcing fabric 35 is assembled. Each tubular layer of reinforcing fabric assembled may be joined to the previous inner tubular layer of reinforcing fabric, for example by thermal welding. However, it is preferred not to connect adjacent tubular layers of reinforcing fabric so that the layers are free to move relative to each other to transfer loads and stresses, whereby the layers can accept their load share.

Typically, air is removed from the tubular layer of reinforcing fabric 35 prior to infiltration with the resin adhesive.

After the tubular layer 35 of reinforcing fabric is impregnated with the resin adhesive, but before it is cured, the inflatable bladder 24 defined by the inner tube 21 is inflated by introducing an inflation fluid, such as air, into the inflation chamber 29. This causes the inflatable bladder 24 to expand radially toward the flexible outer shell 31, providing form and shape to the surrounding outer portion 13. In particular, the outer portion 13 exhibits a circular cross-section.

Continued expansion of the bladder 24 stretches the tubular layer of reinforcing fabric 35 in all directions as the bladder 24 moves past the compression device 125 to improve the hoop and axial stress bearing characteristics of the pipe 10. In particular, the expansion serves to pre-stress the fibers within the tubular layer of reinforcing fabric 35 to improve hoop stress bearing characteristics, and also to axially tension the tubular layer of reinforcing fabric to axially pre-stress the fibers therein to improve the tensile load bearing properties of the pipe 10.

The flexible outer shell 31 serves to resist radial expansion of the tubular layer 35 of reinforcing fabric, thereby causing the reinforcing elements 32 to undergo radial compression. With this arrangement, the reinforcement 32 is confined within the space 45 between the inner dilation tube 21 and the flexible outer sheath 31. The radially expanded inner tube 21 operates with the flexible outer sheath 31 to confine the reinforcement 32 and also to cause a gradual reduction in the volume of the space 45 that confines the reinforcement 32. This forces the resin adhesive within the reinforcement 32 to be fully impregnated into the reinforcement 32; that is, the layer 33 of reinforcing fabric 34 constituting the tubular layer 35 becomes completely "wet out". In particular, the compressive force is also provided to the reinforcement 32, effectively pumping the resin binder out through the layer 33 of reinforcement fabric 34 to distribute the resin binder in a controlled and limited manner within the space 45. A particular feature of this embodiment is that the steps of delivering the resin adhesive to the stiffener and completely wetting the stiffener 32 with the resin adhesive are separate and distinct behaviors.

Furthermore, the gradual reduction in the volume of the space 45 in which the reinforcement 32 is confined also entails the evacuation of air from the space 45, which has the effect of improving the penetration of the resin binder in the reinforcement 32. The outer shell 31 and the respective tubular layers 35 of reinforcing fabric are designed to facilitate the evacuation of air. This air venting is facilitated by the air-permeable layer defined by the fibrous inner layer of the outer shell 31. Furthermore, the outer shell 31 and the respective tubular layers of reinforcing fabric 35 may, for example, comprise ventilation holes arranged at intervals over their respective lengths, to facilitate the evacuation of air, as shown in fig. 9. In one configuration, the vents 48 may form perforations, such as through-holes, in the outer shell 31 and each of the tubular layers of reinforcing fabric 35. With this construction, the perforations can ultimately be sealed with a resin adhesive to ensure the sealing integrity of the tube 10. In another arrangement, the vents may comprise ports that are inserted into the outer shell 31 and the respective tubular layers of reinforcing fabric 35. The port may comprise, for example, a tubular insert formed of a material that dissolves or degrades upon exposure to the resin binder. With this construction, the small hole of the receiving port is eventually sealed with a resin adhesive to ensure the integrity of the seal of the tube 10.

The flexible outer shell 31 has some elasticity so as to be compliant at least to some extent against radial expansion of the tubular layer 35 of reinforcing fabric. In this manner, the flexible sheath 31 is able to cushion the initial stages of the radially outer growth of the tubular layer 35 of reinforcing fabric. In particular, it is desirable that the flexible enclosure 31 has a certain elasticity. The flexible outer shell 31 has some elasticity that serves to enhance control over the rate at which the ascending pool of resin binder gradually saturates the reinforcement 32. On the one hand, if the resin binder rises too fast in the spaces 45, it is not possible to completely saturate the fibers in the reinforcement 32, and on the other hand, if the resin binder rises too slowly in the spaces 45, the resin binder begins to harden before the fibers in the reinforcement 32 are completely saturated.

The resilient nature of the flexible casing 311 fitted around the stiffener 32 acts to some extent as a surround for controlling the external pressure applied to the resin adhesive rise tank. The elasticity of the flexible housing 31 can be selected to achieve a desired wetting rate. The spring force exerted by outer shell 31 provides some degree of balance to the tension force exerted by inflatable bladder 24 defined by inner tube 21.

The inflatable bladder 24 is maintained in an inflated condition until the resin binder has hardened sufficiently to ensure the shape and form of the tube, whereupon the inflation fluid may be released from the inflation lumen 29. Thereby forming a tube 10 with a central flow passage defined within the tube by the liner 15.

The inner pipe 21 may be implemented as part of the construction process of the pipe 10 or assembled on site.

In the environment of the preformed inner tube 21, the inner tube 21 is delivered to the site in a collapsed condition. The inner tube 21 may be collapsed in any suitable manner. Typically, the inner tube 21 is folded into a collapsed condition by folding in a folding manner to provide a more compact cross-sectional configuration. In the configuration shown in fig. 10 and 11, the inner tube 21 is contracted into a flat-cross-sectional state by a folding manner defining two longitudinal side portions 51 and a folded portion 52 therebetween. With this structure, the longitudinal side portions 51 can be brought into contact with each other in proximity to provide a compact form. In the configuration shown in fig. 12-15, the inner tube 21 is collapsed into a flattened cross-sectional configuration using a folding pattern defining two longitudinal side portions 53 and a female fold 54 therebetween. With this structure, each of the concave folds 54 extends inward from one longitudinal side of the contracted inner tube 21. Fig. 13 is a schematic cross-sectional view of the inner tube 21 in a folded state. In fig. 14, the inner tube 21 is in a partially flattened state. In fig. 15, the inner tube 21 is in a completely flattened state. During the manufacture of the tube 10, the inner tube 21 is in a different state at each stage.

The reinforcement 32 is fitted around the inner tube 21. In particular, a tubular layer 35 of reinforcing fabric is in turn fitted around the inner tube 21. As described above, each tubular layer 35 of reinforcing fabric is assembled from strips 41 of reinforcing fabric material each having longitudinal edges 43 joined together in overlapping relationship at joints 44 to form a tubular structure.

The individual tubular layers 35 are arranged in a series 36 having an innermost tubular layer 35a, an outermost tubular layer 35b, and one or more intermediate tubular layers 35c interposed between the innermost tubular layer 35a and the outermost tubular layer 35 b. The series of tubular layers 35 have progressively increasing diameters to provide better fit and alignment with one another to provide structural precision of the tube 10. To accommodate the increasing diameters between the tubular layers 35, the corresponding strips of reinforcing fabric material 41 need to be of different widths that gradually increase from the innermost tubular layer 35a to the outermost tubular layer 35 b. Each tubular layer 35 is designed to be inflated, opened or deployed to its maximum diameter by the inflation force of the fluid pressed against the inner tube 21, thereby providing a fully expanded assembly in which the fibers bear the load of the tube 10 during operation.

As described above, each tubular layer 35 in the series 36 is positioned such that the joints 44 are offset from each other, as shown in FIG. 8.

Each tubular layer 35 is assembled from the respective strips 41 by progressively moving the strips 41 from a first condition in which the strips are flat to a second condition in which the strips are of a tubular configuration with edges 43 overlapping. In fig. 16, the strip 14 is shown with one portion 41a in a first (flattened) state and another portion 41b in a second (tubular) state. In the first state, the strip 41 may be stored in a wound form 55 on a reel 56, as shown in fig. 16.

The assembly system 60 is used to gradually move the strips 41 from the first (flattened) state to the second (tubular) state and to fit the overlapping edges 43 together to create the joint 44 to form the tubular layer 35. As the strip 41 moves from the first (flattened) state to the second (tubular) state, it progressively surrounds the inner tube 21.

The fitting system 60 comprises a guide system 61 for gradually moving each bar 41 from the first (flat) condition to the second (tubular) condition. As shown in fig. 17, the guide system 61 includes a guide rail 62, the guide rail 62 including a body 63, the body 63 defining an inlet end 64, an outlet end 65, and a guide path 66 extending between the inlet end and the outlet end. The main body 63 is configured as a tubular structure 67 having longitudinal edge portions 68, the longitudinal edge portions 68 being arranged in overlapping relation with one another and spaced apart to define a longitudinal gap 69 therebetween. The tubular structure 67 is configured such that the guide path 66 tapers inwardly from the inlet end 64 to the outlet end 65. With this arrangement, the tubular structure 67 can provide a tapered guide surface 67a that is presented to each bar 41 as each bar 41 progresses along the guide path 66 from the inlet end 64 to the outlet end 65, and that gradually transitions the bars 41 from a first (flattened) condition at the inlet end 64 to a second (tubular) condition at the outlet end. As the strip 41 moves along the guide surface 67a, the longitudinal edges 43 of the strip are turned progressively inwards by the tapering profile, one side of the longitudinal edge 43 of the strip 41 partially entering the longitudinal gap 69 of the tubular structure 67 and the other side of the longitudinal edge 43 protruding above the inner edge 68 a. With this arrangement, the longitudinal edges 43 are progressively joined together in an overlapping manner ready to be fitted together to establish the joint 44 and complete the formation of the tubular layer 35.

As strip 41 is installed into the tubular structure to form tubular layer 35, inner tube 21 also moves along guide path 66 from inlet end 64 to outlet end 65. In this way, the tubular layer 35 may be fitted around and thereby surround the inner tube 21.

Similarly, the innermost intermediate tubular layer 35c may be installed around the tubular layer 35a and the inner tube 21, the tubular layer 35a being formed around the inner tube 21, and then any other intermediate tubular layer 35c and finally the outermost tubular layer 35b may be installed around the previous tubular layer 35.

The tubular structure 67 may incorporate means for attracting and retaining the strip 41 with respect to the guide surface 37 a. Such means may include a suction system comprising a plurality of holes on the guide surface 67a to which suction is applied to draw the strip 41 into contact as it moves along the guide path 66.

The assembly system 60 further includes guide rollers 71 about which each bar 41 rotates on its way from the reel 56 to the inlet end 64 of the tubular structure 67 to accurately align the bar 41 for entry into the tubular structure 67.

The assembly system 60 still further includes a bonding system 71 for bonding the overlapping edges 43 together to create the joint 44 to complete the formation of the tubular layer 35. As shown in fig. 18, bonding system 71 includes a device 72 for applying hot melt adhesive between overlapping edges 43 and then joining the edges together to create joint 44. In the illustrated construction, such means 72 comprise a transfer head 73 for transferring one or more hot melt adhesive strips 74 between the overlapping edges 43. The delivery head 73 is adapted to receive a supply of hot melt adhesive from a source 75 by way of a delivery line.

Bonding system 71 still further includes means 76 for joining the overlapping edges together with the hot melt adhesive between overlapping edges 43 to create joint 44. In the illustrated construction, such means 76 comprise a ram 77 for pressing the overlapping edges 43 together. The press head 77 comprises two cooperating press rollers 78 between which the overlapping edges 43 pass, being pressed together to establish the joint 44 by means of the hot melt adhesive. Although not shown in the figures, the mounting system 60 may further include means for facilitating rapid placement of the hot melt adhesive. Such means may include structure for delivering a coolant, such as chilled air, to the vicinity of the joint 44.

The construction process of the tube 10 according to the present embodiment will be described in detail below. In this embodiment, the tube 10 is constructed on a continuous basis and is gradually placed into the trench 79 for receiving the tube. The tube 10 is placed in the channel 79 prior to curing of the resin binder impregnated into the reinforcing fabric 34 and felt layer 17 of liner 15. Curing occurs after the pipe 10 is placed into the trench 79. In this manner, the tube 10 is in a soft state so that it is guided into place in the canal and, once in place, hardens.

Referring now to fig. 1, the pipe 10 is mounted to a mobile mounting device 80 configured in the form of a vehicle capable of moving along the trench 79 so that the continuously formed pipe 10 can be bent from the mobile mounting device 80 into the trench 79. The pipe 10 may be cured in the trench 79 in any suitable manner. In the illustrated construction, the curing unit 71 is provided to move progressively along the duct 79 to apply a curing operation to the recently placed length of pipe. The curing unit 71, for example, may apply heat or other radiation, such as UV radiation or light (depending on the properties of the resin binder), to the tube 10 to assist in the curing process. In an alternative construction, the resin binder may contain a suitable catalyst to cure the tube in ambient conditions.

The mobile mounting apparatus 80 includes a tube assembly line 82, as shown in fig. 19 (which is shown in two parts, fig. 19A and 19B).

Referring to fig. 19A, an assembly line 82 includes a supply of material 83 in the form of a strip and stored on rollers 85. Material 83 provides liner 15 with a layer of resin adhesive material 17 adhered thereto. The material 83 is gradually unwound from the roller 85 and conveyed as a strip 23 to a first assembly station 87 where the strip 23 is formed into an inner tube 21. As previously described, the strip 23 is longitudinally wound into a tubular configuration to provide the inner tube 21, the longitudinal edges 25 abut to form an abutment joint 26, and a connector strip 27 is applied to the inside of the inner tube 21 to overlap the abutment joint 26 to provide a continuous, fluid impermeable connection.

The assembly line 82 further comprises one or more supplies of material 91, each in the form of a strip and stored in the form of a roll 55 on a respective reel 56. In the configuration shown in fig. 19A, there are two spools 56, but other numbers are possible. Material 91 provides a reinforcing fabric 34 containing reinforcing fibers having the characteristic of a tetraxial fiber orientation. The material 91 is gradually unwound from the respective reel 56 and passes as a strip 41 to a second assembly station 95, where it forms the respective tubular layer 35 of reinforcing fabric around the inner tube 21. As previously described, each tubular layer 35 of reinforcing fabric is formed from strips 41 of reinforcing fiber material that are joined together in an overlapping relationship to form the tubular layer. The overlapping edges 43 are fitted together to ensure tubular formation. In this embodiment, the overlapping edges 43 are mounted together by thermal welding. As previously described, the tubular layers 35 are disposed adjacent to one another and around the inner tube 21. Adjacent fabric layers 33 are bonded together by a thermal welding or chemical bonding process. The layers may include a bonding agent or forming material to more effectively bond the layers together. This may for example comprise a chopped strand felt, felt or net to increase the laminar shear force between the high strength tetraaxial fabric layers and to allow easier release of air from the laminate.

The tubular layer 35 of reinforcing fabric and the inner tube 21 provide the tubular structure 100. The tubular structure 100 is conveyed to a third station 103 where it is compressed between press rolls 105 to expel air outwardly and bring the resin adhesive into direct contact with the reinforcement 32 and the adjacent layer 17 of resin absorbent material.

The tubular structure 100 is then transferred to a fourth station 105 where it is impregnated with a resin adhesive. In the illustrated construction, the tubular structure 100 is passed through a resin bath 107 and looped between rollers 109 to attach the resin binder to the felt 17 and reinforcing fabric 34. At least some of the rollers 109 are driven to assist in the movement of the tubular structure 100.

The tubular structure 100 is then passed to a fifth station 111 where it is engaged by a spreader roll 113 to remove excess resin binder and collect it in a water collection area 115.

The tube structure 100 impregnated with the resin adhesive is then transferred to a sixth station 117 where the flexible enclosure 31 is installed to complete the assembly of the tube structure 100. Referring now to figure 19B, the assembled tubular structure 100 is transferred to a seventh station 121 at which a compression device 125 is provided which includes two ring drives 127 defining a passage 129 through which the tubular structure 100 can pass. The assembled tube structure 100 is compressed in the channels 129 to define a blocking region 123 that blocks the passage of air along the interior of the assembled tube structure. The two ring drives 127 comprise opposing elements 131, such as cleats, operable to space the pinch tube structure 100 and close the air flow path while allowing resin adhesive impregnated in the tube structure to pass through the plugged channels 129.

The compression device 125 also applies a traction force to the assembled tubular structure 100 to convey it along its path.

The section 100a of the assembled tubular structure 100 beyond the device 125 is expanded by introducing an expansion fluid, such as air, into the interior, which defines the expansion chamber 29. This causes the assembled tubular structure 100 to expand radially and axially simultaneously, providing its form and shape. Expansion of the assembled tubular structure 100 stretches the reinforcing fabric tube 35 in all directions for improving the hoop and axial stress carrying properties of the tube 10. In particular, this expansion also serves to pre-stress the fibers within the tubular layer of reinforcing fabric 35 to enhance hoop stress bearing properties, while also axially stretching the tubular layer of reinforcing fabric to axially pre-stress the fibers therein to enhance tensile load bearing properties of the tube 10.

Since the plugged region of the end assembled tubular structure 100 is closed as previously described, the inflation fluid does not escape from the inflation lumen 29. In other words, the compression device 125 may act as a valve closing the interior of the tubular structure 100 to prevent the expansion fluid from escaping from the expansion chamber 29. In addition, the compression device 125 may also act as a brake to hold the expansion load applied by the inflation of the inner tube 21 with the inflation fluid. Still further, the compression device 125 may be used as a driver to initiate the process flow before aeration begins.

As previously mentioned, the flexible outer shell 31 serves to resist radial expansion of the tubular layer 35 of reinforcing fabric, thereby enabling the reinforcement 32 to withstand radial compression. The reinforcement 32 is confined in the space 45 between the inner expansion tube 21 and the flexible outer shell 31. The radially expanded inner tube 21 is operatively used with the flexible outer shell 31 to cause a gradual reduction in the volume of the space 45 in which the reinforcement 32 is confined. This causes the resin binder in the reinforcement 32 to gradually increase in the space 45 to displace air, eventually completely penetrating into the reinforcement 32; that is, the layer 33 of reinforcing fabric 34 configured as a tubular layer 35 becomes completely "wet out". In this manner, the resin binder is forced through layer 33 of reinforcing fabric 34, distributing the resin binder in spaces 45 in a controlled and limited manner.

A particular feature of this embodiment is that the step of delivering the resin adhesive to the reinforcement 32 and the step of completely wetting the reinforcement 32 with the resin adhesive are separate and distinct operations. In particular, the resin adhesive is introduced into the tubular structure 100 before the tubular structure 100 passes through the compression device 125, and the resin adhesive completely wets the reinforcement 32 immediately after the tubular structure 100 has passed through the compression device 125, as the inflation fluid is introduced into the inflation lumen 29.

Further, the gradual decrease in the volume of the space 45 in which the reinforcement 32 is located functions to discharge air from within the space 45, which has the effect of improving the impregnation of the resin adhesive in the reinforcement 32, as described above.

At this stage, the resin adhesive is not cured, so that the section 10a of the pipe 10 installed in the mobile installation apparatus 80 is in a flexible state. The uncured section 10a of the pipe 10 exits the mobile installation apparatus 80 and is guided into the trench 79 as previously described. The pipe 10 is cured in the channel 79 in any suitable manner. In the illustrated construction, the curing unit 71 is moved stepwise along the pipe trench 79 to apply a curing operation to the section of pipe most recently resting.

The assembled tubular structure 100 is maintained in an inflated condition until the resin binder has hardened sufficiently to maintain the form and shape of the tubular 10, and subsequently the inflation fluid is released from the inflation lumen 29. The tube 10 is thus formed and the liner 15 defines a central flow passage in the tube 10.

The tubular structure 100 may have a beginning 133 and a terminal 135 because it is assembled step-by-step as previously described. Typically, an inflation fluid, such as air, for the inner tube 21 is introduced through the beginning 133 of the tubular structure 100.

Fig. 20 shows the start 133. In the illustrated construction, the beginning 133 is mounted with an end fitting 136, the end fitting 136 including an end flange portion 137 and a sleeve portion 138. When the beginning 133 emerges from the compression device 125, the end fitting 136 is immediately mounted to the beginning 133. The installation step includes inserting the sleeve portion 138 into the end of the tubular structure 100 and then clamping the starting end 133 to the sleeve portion, typically by a clamping means 139, such as a snap or clamp ring. A ring (not shown) is mounted to the beginning 133 so that it is shaped to receive the sleeve portion 138 of the end fitting 136.

The flange portion 137 has a supply 141 for communication with a fluid line 142 for conveying an expansion fluid into the inner pipe 21. In the illustrated construction, the supply 152 includes a port 143 through which the delivery end of the fluid line 142 extends.

Fig. 21 and 22 show the terminal 135. In the illustrated construction, the terminal end 135 is mounted with an end fitting 144 closing the end. The end fitting 144 includes a clip 145 adapted to clampingly engage the tubular structure to sealingly close the terminal end 135. The clip 145 is adapted to be mounted to the tubular structure 100 after the tubular structure 100 has been assembled, but before being passed through the compression device 125. The clip 145 is adapted to pass through the passage 129 between the two ring drives 127 without interfering with the operation of the opposing elements 131 which cooperate to pinch the tubular structure at intervals along the passage 129. The arrangement is such that the clip 145 moves in synchronism with the two ring drives 127 so that the position of the clip 145 along the channel does not coincide at any stage with the point at which the tubular structure 100 is pinched by the opposing elements of the two ring drives 127 which cooperate with one another. In this way, the clip 145 can pass along the channel 129 while being connected to the tubular structure 100, without interfering with the operation of the counter element 131.

In particular instances, it may be desirable for the end of the tubular structure 100 adjacent the terminal end 135 to have a particular cross-sectional shape. In this case, a contour shaping system 146 may be used, as shown in FIG. 22. The contour-forming system 146 includes an outer mold 147 corresponding to the desired contour, the arrangement being such that after the end of the tubular structure 100 adjacent the terminal end 135 exits the compression device 125, it passes through the mold 147. Internal pressure is applied to the end of the tubular structure 100 adjacent the terminal end 135 to urge the end outwardly into contact with the mold 147 to facilitate application of the desired profile to the end. In the illustrated construction, internal pressure is applied via an inflation assembly comprising an inflatable bladder 148 and an associated flexible fluid delivery line 149 along which inflation fluid may be delivered to inflate the bladder 148. Inflatable bladder 148 is adapted to be inserted into the end of tubular structure 100 adjacent terminal end 135 prior to attaching clip 145 to terminal end 135. The fluid transfer path 149 extends to the exterior of the tubular structure 100 through a specially formed aperture in the tubular structure 100. Inflatable bladder 148 is inserted into the end of tubular structure 100 in a deflated condition and passes through compression device 125 in a deflated condition along with flexible fluid transfer path 149. Once the terminal end 135 exits the compression apparatus 125, the bladder 148 is inflated, but before the end of the tubular structure 100 adjacent the terminal end 135 is engaged by the mold 147. Inflation of bladder 148 applies internal pressure to the end of tubular structure 100 adjacent terminal end 135, urging the end outwardly into contact with mold 147 so that the desired contour may be imparted to the end.

A particular feature of this embodiment is that the step of delivering the resin adhesive to the reinforcement 32 and the step of completely wetting the reinforcement 32 with the resin adhesive are separate and distinct operations. In particular, the resin binder is transferred to the reinforcement before the tubular structure 100 passes through the compression device 125. After the tubular structure 100 has passed through the compression device 125, the inner tube 21 is inflated.

Inflation of the inner tube

Referring now to fig. 23 (which includes two parts, fig. 23A and 23B), a pipe assembly line for pipes according to a second embodiment is shown. The tube assembly line 150 is similar in some respects to the tube assembly line 81 used in the first embodiment, corresponding reference numerals being used to indicate corresponding parts.

The second embodiment does not use a resin bath (as is the case in the first embodiment) to wet the tube structure 100 with resin adhesive. Instead, the resin adhesive is transferred to the assembled tubular structure 100.

Referring to fig. 23A, the flexible enclosure 31 is mounted around the assembled portion of the outer tubular structure 100 to contain a resin adhesive, as will be described in more detail later. The housing 31 may be formed of any suitable material including, for example, polyethylene. The housing 151 remains in place and eventually forms an integral part of the tube or may be removed after its purpose is completed. The material 153 of which the housing 31 is assembled is in the form of a strip and stored on a reel 155. The material 153 is gradually unwound from a reel 155 and conveyed in strips 156 to a station 157 where the strips are assembled into a tube 159, the tube 159 providing the housing 31. The tube 159 is assembled from the strips 156 by connecting the longitudinal edges of the strips 156 together in an overlapping manner to form a tube. The overlapping edges are joined together by any suitable means, such as by sewing, welding or stapling, to ensure tubular formation.

The resin adhesive is transferred into the flexible cover 31 through the open end 161 of the flexible cover 31. The resin adhesive is transferred along a transfer line 163 extending into the flexible enclosure 31 through the open end 161 and having an exit end 162 disposed inwardly of the open end 161. The delivery line 163 receives resin from a reservoir 165, such as a supply tank. A pump 167 is used to pump the resin along the delivery line 163 from the reservoir 165 to the outlet end 162. The resin adhesive is transferred into the flexible housing 31 to a pool 171 at the bottom of the tube 159, which tube 159 provides the housing 31.

The assembled tubular structure 100 is compressed to define the plugging region 123 by a compression means 125 comprising two annular drives 127. Opposing elements 131 (e.g., cleats) on the two ring drives 127 cooperate to pinch the tubular sub-structure 100 and close it against the air passage, but allow the impregnated resin adhesive confined within the flexible enclosure 31 to flow through the plugged passage 129. The action of the cooperating elements 131 serves to pinch the assembled tubular structure 100 and housing 131 at intervals. This causes the resin binder contained in the housing 31 and collected at the bottom thereof to collect in "puddles" in the sections of the housing 31 between each set of interfitting members 131 as shown in fig. 24.

As the assembled tubular structure 100 is gradually moved beyond the compression passages 129 defined by the devices 125, a pool 171 of resin binder gradually rises within the annular space 45 between the liner 21 and the surrounding flexible shell 31. The cross-sectional size of the annular space 45 is gradually reduced by the expanded inner tube 21, thereby causing the level of the pool 171 of resin binder to gradually rise. This is schematically depicted in fig. 8B and fig. 10-16, wherein the surface of the pool 171 is indicated by reference numeral 177. The ascending pool 171 of resin binder in the annular space 45 gradually displaces the air in the annular space. The housing 31 is configured to facilitate the discharge of air. This may include providing gas slow release valves spaced along its length within the housing 31 and using a non-woven venting material as part of the housing to facilitate the release of air from the tube along the length of the tube. Additionally, or alternatively, a vacuum point may be provided along the length of the tubular structure 100.

The surface 177 of the ascending pond 171 is formed in a wave-like shape as indicated by the line 179 in fig. 23B.

The ascending pool 171 of resin binder gradually wets out the reinforcement 32 and the adjacent resin absorbent layer 17 of the liner 21. Finally, the assembled tube structure 100 is completely impregnated with the resin adhesive.

Referring now to fig. 32-43, a portion of a tube assembly line 200 for tubes according to a third embodiment is shown. The tube assembly line 200 is in some respects similar to the tube assembly line 150 for the second embodiment, with corresponding reference numerals being used to indicate corresponding parts.

The pipe assembly line 150 for the second embodiment employs a flexible casing 31 mounted around the assembled pipe structure 100 to contain the resin binder and to establish a gradually rising pool 171 of resin binder for gradually wetting out the assembled pipe structure 100.

The pipe assembly line 200 for the third embodiment also employs a flexible housing 31 to contain the resin binder within the assembled outer pipe structure and to establish a gradually rising pool 171 of resin binder.

In this third embodiment, the flexible enclosure 31 is elastic for the purpose of improved rate control, which is the rate at which the ascending pool 171 of resin binder gradually wets out of the assembled tube structure 100. On the one hand, if the pool 171 of resin binder in the annular space 45 rises too quickly, complete wetting of the fibers in the assembled tube structure 100 may not be achieved. On the other hand, if the pool 171 of resin binder in the annular space 45 rises too slowly, it is possible that the resin binder will begin to cure before the fibers in the assembled tubular structure 100 are fully wetted.

The elastic nature of the flexible enclosure 31 acts to some extent as a surround for controlling the external pressure applied to the resin binder's upwell 171. The elasticity of the flexible housing 31 can be selected to achieve a desired wetting rate. The elastic force exerted by the outer shell 31 can balance the tension force exerted by the inflation inner tube 21 to some extent.

In this embodiment, the tube structure 100 is compressed prior to installation of the resiliently flexible housing 31 to complete assembly of the tube structure. In the illustrated construction, compression of the tube structure 100 is accomplished by passing it through a constriction 180 configured as a funnel.

Referring now to FIG. 44, a portion of a tube assembly line 300 for tubes according to a fourth embodiment is shown. The tube assembly line 300 is in some respects similar to the tube assembly line 81 used in the first embodiment, corresponding reference numerals being used to indicate corresponding parts.

In this fourth embodiment, the resin binder is delivered to the individual tubular layers 35 forming the reinforcement during assembly of the tubular structure 100, rather than using a resin bath as used in the first embodiment. The tubular structure 100 is progressively assembled by forming tubular layers 35 of reinforcing fabric around the inner tube 21, each tubular layer 35 being formed by a respective strip 41 of the corresponding assembly system 60, as shown in figure 44. As each tubular layer 35 of reinforcing fabric is assembled, a quantity of resin adhesive is deposited on the inside of the tubular layer. Alternatively, the resin adhesive may be sprayed, roll coated, or otherwise applied to the exterior of each tubular layer 35 after each tubular layer 35 is assembled. In the configuration shown in fig. 44, a delivery system 301 is provided, the delivery system 301 serving to deposit a resin adhesive charge on the interior of each tubular layer 35 as each respective strip 41 forming the tubular layer transitions from the first (flattened) state to the second (tubular) state. As shown in fig. 44, a spray roller or other system 303 is also provided for spraying a resin adhesive onto the exterior of each tubular layer 35 after assembly of each tubular layer 35 is complete and before the next tubular layer 35 is installed therearound. With this arrangement, resin adhesive is applied to the reinforcement 32 to fill the vast majority of the available space, while also allowing resin adhesive to move through the various tubular layers 35 to transfer air from the lower region of the space 45 between the expanded inner tube 21 and the flexible outer shell 31 to the upper region of the space for subsequent venting.

In some applications, it may be desirable to have relatively rapid wet-out of the reinforcement 32 and adjacent resin absorbent layer 17 of the liner 21, rather than relying solely on a gradual rising pool of resin binder as described in the previous embodiments. Such an application may, for example, involve a pipeline installation in which the tubular structure 100 has an inclined portion at which the resin adhesive moves downwardly under the influence of gravity without achieving satisfactory wetting of the reinforcement 32 and the adjacent resin absorbent layer 17 of the liner 21.

Referring now to fig. 45, 46 and 47, there is shown a portion of a tube assembly line 400 for tubes according to a fifth embodiment. The tube assembly line 400 is in some respects similar to the tube assembly line 81 used in the first embodiment, corresponding reference numerals being used to indicate corresponding parts.

In the illustrated construction the tubular structure 100 has a section 401 which is steeply inclined to such an extent that the resin adhesive can move downwards under the influence of gravity without satisfactory wetting out of the reinforcement 32 and the adjacent resin absorbent layer 17 of the liner 21 being obtained.

The pipe assembly line 400 includes means 403 for facilitating relatively rapid wetting of the reinforcement 32 and the adjacent resin absorbent layer 17 of the liner 21.

The apparatus 403 includes a plurality of roller columns 405 arranged in a spaced relationship. Each roller row 405 includes a plurality of rollers 407 arranged in a ring 409 that define a central annular space 411 through which the assembled tubular structure 100 passes in a constrained condition.

Each roller row 405 comprises a central shaft 413 configured in a ring, on which the respective roller 407 is rotatably mounted. Due to the annular configuration of the central shaft 413, the rollers 407 are arranged at an angle to each other. The rollers 407 are also arranged close to each other. Due to the angular arrangement and close alignment of the rollers 407, the cylindrical rotating surfaces 415 of the rollers 407 cooperate with each other at the inner side 416 of the circular array 405 to provide a rotating contact surface. Further, at the outer side 420 of the circular row 405, a gap 419 is formed between adjacent rollers 407.

The roller arrays 405 are axially spaced from each other with a space 421 between adjacent roller arrays.

The loops 415 are connected to each other to hold the roller array 405 in place. In the illustrated construction, the shafts 413 are connected together by a connecting rod 426. The presence of the gap 419 between adjacent rollers 407 at the outer side 420 of the circular array 405 provides space for the connection of the connecting rods 423 to the shaft 413.

Once the inner tube 21 is inflated, the device 403 is moved along the assembled tubular structure 100. In the configuration shown in fig. 45, the device 403 is disposed proximate the rear of the device 125.

Typically, the device 403 is pulled along the assembled tubular structure 100, behind the compression device 125.

The apparatus 403 is also adapted to impart vibrations to the tubular structure 100 to agitate the resin binder and enhance the wetting process.

With this arrangement, as shown in fig. 48, as the tubular structure 100 passes through the device 403, the tubular structure 100 is subjected to a similar operation to a peristaltic pressing action. In particular, the tubular structure 100 is compressed as it passes through each central annular space 411, and then the tubular structure 100 expands towards the intermediate space 419 under the influence of the inflation pressure within the inner tube 21. This continued compression and expansion causes the assembled tubular structure 100 to disperse the resin binder and facilitate relatively rapid wetting out of the reinforcement 32 and adjacent resin absorbent layer 17 of the liner 21.

The previous embodiments relate to the construction of a tube 10 which is progressively placed in a trench for receiving the tube.

The present application, including tubes according to the various embodiments described and illustrated, is not limited to tubes that are progressively placed in a trench for receiving the tube.

The pipe is also adapted to be placed on the ground, directly or indirectly on support means, such as suspension brackets placed along its length. The tubes may also be supported in an elevated state, such as equipment in an industrial or chemical plant.

One particular feature of a tube constructed in accordance with the present invention is: it may be constructed and then installed in place before the resin binder cures. In this manner, the tube is in a flexible condition to facilitate its being guided to the appropriate installation location and then once installed in place, the tube hardens as the resin adhesive cures. In this manner, the tube in a flexible state may be carried or transferred to a desired location and then installed before the resin binder is cured.

This is particularly advantageous where the tube is required to detour around one or more obstacles along a path, or where the tube is required to follow a tortuous path. This is often the case for pipelines in industrial or chemical plants.

Referring now to fig. 49-52, there is shown a section of a tube 10 according to a sixth embodiment. The pipe 10 according to the sixth embodiment comprises one or more straight sections, one of which is shown in figure 49 and is indicated with reference numeral 501. The tube 10 may also include one or more curved sections, one possible form of which is shown in figure 50 and indicated by reference numeral 503, and other possible forms are shown in figure 51 and indicated by reference numeral 505.

Curved section 503 is configured as a gradually curved curve having an exterior side 507 and an interior side 509. The flexible cover 31 is stretched on the outside 507 and contracted on the inside 509 to accommodate the curvature. The fibers in the stiffener 32 can slip to accommodate curvature and distribute loads.

Curved section 505 is configured as a relatively sharp curve having an outer side 511 and an inner side 513. The curved section 505 is formed by removing a section of the assembled tubular structure 100 adjacent the inner side 513, as shown in fig. 52, to create a concave shape 515 along the inner side to facilitate folding the tubular structure to form the assembled tubular structure 100. In the illustrated construction, the removed sections are of a V-shaped configuration such that each female formation 515 has two opposing angled sides 517 that abut in overlapping relationship over the curved section 505, as shown in FIG. 51. The abutting edges 517 are sealingly bonded together.

In some applications it is desirable that the tube 10, or at least a section of its length, remain flexible after construction of the tube and curing of the resin binder. This application includes the provision of a pipe 10 having a flexible line extending between a submerged location and equipment at the surface.

Fig. 53 shows a tube 10 according to a seventh embodiment, which is configured for use in such an application. The pipe 10, for example, may provide a flexible riser between a subsea location and a surface production rig. In this embodiment the pipe 10 is mounted to a mounting device 600 on a marine vessel, such as a boat or barge, and the pipe 10 is placed in water 601, the surface of which is indicated by reference numeral 603.

The mounting device 600 is fitted with a tubular structure 100 in a similar manner to the previous embodiments. In such an embodiment, installation apparatus 600 employs means 403 to facilitate relatively rapid wetting of reinforcement 32 and adjacent resin absorbent layer 17 of liner 21, as previously described in relation to the fifth embodiment. The mounting device 600 further has a support structure 605 for supporting the assembled tubular structure 100 when it is placed in the water 601.

In this embodiment, the resin binder used during construction of the tube 10 is hardened, but in a softer state (as opposed to hardened to a rigid state as described in the previous embodiments). In particular, the resin binder remains flexible after curing to provide the desired flexibility to the tube 10. Resin adhesives and other adhesives suitable for such purposes are well known in the art of composite construction, examples of which include modified rubber polyesters, modified rubber vinyl esters, and modified rubber epoxy polyurethanes. In this embodiment, rubber modified vinyl ester is preferred as the resin binder because it has high shear strength and excellent interlayer adhesion, and also provides some ability to accommodate movement to the structure.

Because of the need to lower the assembled tubular structure into the water when resting the pipe 10, the use of air as the inflation fluid for the liner 21 may not be suitable because air can create undesirable buoyancy forces on the assembled tubular structure. In this embodiment, water is used as the expansion fluid. The water as the expansion fluid comes from the surrounding body of water 601. In the illustrated construction, the bottom of the descending tubular structure (i.e., its beginning 133) has a fitting 607 through which water is pumped into the tubular structure 100 to inflate the liner 21. An expansion fluid is introduced to establish and maintain a water level above the water surface 603 to establish a pressure head for pressurizing the water sufficiently as needed to expand the liner 21. The level of the tubular structure 100 above the water surface 603 is indicated by reference numeral 611.

In this embodiment, the compression device 125, in addition to applying traction for movement relative to the tubular structure as in the previous embodiments, may also be used as a brake system to control the raising and lowering of the assembled tubular structure 100.

The foregoing embodiments relate to the construction of a length of tubing constituting a pipeline that extends continuously between two remote stations. However, the present invention is not necessarily limited to such a long tube configuration. The invention is also applicable to the production of other pipes, such as pipes suitable for connection to each other to form a pipeline, and other shorter pipes which may be used for handling and installation operations as separate units. The production of these pipes can be adjusted in a production plant, such as a factory.

The next embodiment, not shown in the drawings, refers to such a tube. This embodiment is similar in some respects to the previous embodiments and corresponding terminology is used in the description of the embodiments.

In this embodiment, the inner portion is placed on a core (e.g., mandrel) adapted for axial and radial expansion, and the outer portion is disposed about the inner portion to provide an assembled tubular structure. The outer portion is disposed around the inner portion before, during and after the inner portion is placed on the core. The resin binder impregnated into the reinforcing fabric of the outer portion can also be impregnated into the batt layer on the liner to integrate the outer portion with the inner portion as in the previous embodiments. Before the resin binder cures, the core expands, causing the assembled tubular structure to expand both radially and axially, thereby providing form and shape. Expansion of the assembled tubular structure stretches the reinforcement in the outer portion in all directions for improving the hoop and axial stress bearing properties of the tubular 10, as described in the previous embodiments. Once the resin binder has sufficiently cured, the assembled pipe 100 is removed from the core, thereby completing the production of the pipe.

In this embodiment, the core is used to radially and axially expand the assembled tubular structure, rather than passing an expansion fluid as in the previous embodiments.

In another alternative, a relatively short pipe is first produced by a method according to any of the first, second or third embodiments, and then the pipe is cut into sections, each of which forms a pipe spool.

The pipe according to any of the preceding embodiments requires a coupling at one or both ends thereof. Couplings are required to connect the pipe to other pipes on the pipeline or to connect the pipe to another component (e.g. a filter, a pump and a valve). In addition, it is necessary to install the coupling to the pipe at the beginning and end of the pipe production construction process.

The coupling may be mounted to the pipe end by any suitable means. One way may comprise a coupling device with an anchoring portion configured for connection to a pipe and a coupling portion in the form of a coupling (e.g. a coupling flange) for connection to a corresponding coupling on another other pipe or to a component to which the pipe is to be coupled.

The anchoring portion is adapted to be embedded in the adjacent end of the pipe 10. The anchoring portion may be configured to be keyed to the tube. The keying may be achieved in any suitable manner, such as by providing a profile that keys with the exterior 13 of the tube 10. The molding includes lateral projections, such as pins, which are bonded to the stiffener 32 and the resin adhesive impregnated therein. Or, alternatively, the molding may be a hole in which the reinforcing member 32 and the resin binder impregnated therein are located to function as a key. In addition, the fibers in the reinforcement 32 can be wrapped around, inserted into, or otherwise connected to the form to help mount the anchor in place.

The foregoing embodiments relate to the construction of a composite tubular structure constructed as a pipe.

The present invention may be applied to the construction of any suitable tubular structure, including, for example, various tubular objects, elements, parts or other formations. Tubular structures include structural elements such as shafts, beams and columns. The tubular structure may also include hollow structural sections of composite construction and conduits.

The tubular structure may be constructed in any suitable manner. A particularly convenient method of constructing such a tubular structure is similar to that described in the previous embodiment which includes a core (e.g. mandrel) for axial and radial expansion, the outer portion being disposed about the inner portion to provide an assembled tubular structure which constitutes the tubular structure.

The feature of applying vibration to the assembled tubular structure 100 to agitate the resin binder and enhance the wetting process may also be used to construct any of the elongated hollow structures according to the present invention.

In view of the foregoing, a particular feature of the embodiment described is that the step of transferring the resin adhesive to the reinforcement 32 is a separate and distinct operation from the step of completely wetting the reinforcement 21 with the resin adhesive. In particular, the resin binder is introduced into the tubular structure 100 before the tubular structure 100 passes through the compression device 125, and after the tubular structure 100 passes through the compression device 125, the resin binder completely wets the reinforcement 32 as the expansion fluid is introduced into the expansion chamber 29.

Further, the gradual decrease in the volume of the space 45 in which the reinforcement 32 is located promotes the air within the space 45 to be discharged, which has the effect of improving the resin binder permeation in the reinforcement 32, as described previously.

It should be appreciated that the scope of the invention is not limited to only the described embodiments.

Throughout the specification and claims, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A method for constructing an elongate hollow structure comprising a radially inner portion and a flexible radially outer portion which merge together to provide a complete tubular wall structure, the method comprising:

providing the radially inner portion;

providing the flexible radially outer portion around the radially inner portion, the flexible radially outer portion being less elastic than the inner portion to compliantly resist radial expansion of the inner portion, wherein the flexible radially outer portion comprises an outer tube of fiber-reinforced composite construction surrounded by a flexible outer shell and further comprising a reinforcement and an adhesive;

wherein a space exists between the radially inner portion and the flexible radially outer portion; and

expanding the interior, wherein gas within the space is exhausted when the interior is expanded.

2. The method of claim 1, wherein the gas is air.

3. The method of claim 1, wherein the gas is vented via a vent.

4. The method of claim 1, wherein

The flexible outer portion comprises a fibrous material, and

the gas is expelled through the fibrous material to assist in the displacement of the fluid.

5. The method of claim 3, wherein the venting means is implemented as perforations formed in the flexible exterior.

6. The method of claim 1, wherein the reinforcement further comprises one or more layers of reinforcing fabric.

7. The method of claim 6, wherein each of the one or more layers of reinforcing fabric is configured as a tubular layer disposed about the interior.

8. The method of claim 7, wherein there are multiple tubular layers disposed around each other and around the interior.

9. The method of claim 6, wherein the inner portion further comprises an inner liner to one side of which a fabric layer is bonded, wherein the adhesive also penetrates into the fabric layer to bond the flexible outer portion and the inner portion together.

10. The method of claim 1, wherein the flexible outer portion is configured to resist radial expansion of the stiffener, thereby subjecting the stiffener to radial compression.

11. The method of claim 9, wherein the reinforcement is confined in a space between the expanded inner portion and the flexible outer portion such that the radially expanded inner portion operates with the flexible outer portion to cause a gradual reduction in volume of the space such that the adhesive in the reinforcement is fully impregnated into the reinforcement.

12. The method of claim 10, wherein the reinforcement is confined in a space between the expanded inner portion and the flexible outer portion, such that the radially expanded inner portion operates with the flexible outer portion to cause a gradual reduction in volume of the space to expel gas from the space.

13. The method of claim 9, wherein the reinforcement is confined in a space between the expanded inner portion and the flexible outer portion such that the radially expanded inner portion operates with the flexible outer portion causing a gradual reduction in volume of the space such that the adhesive in the reinforcement is fully impregnated into the reinforcement and also expels air from the space.

14. The method of claim 7, wherein the outer and respective tubular layers of reinforcing fabric are configured to facilitate the venting of air.

15. The method of claim 7, wherein the elasticity of the flexible outer portion helps compliantly resist radial expansion of the tubular layer of reinforcing fabric.

16. The method of claim 1, wherein the flexible outer flexible shell is less elastic than the inner portion.

17. The method of claim 15, wherein the flexible outer portion has an elasticity for improved control of the rate at which the adhesive progressively wets the stiffener.

18. The method of claim 6, wherein the reinforcing fabric comprises a reinforcing fabric comprising reinforcement fibers having a tetraxial fiber orientation characteristic.

19. An elongated hollow structure constructed according to the method of claim 1.

20. An elongate hollow structure of modular construction comprising:

a radially inner portion configured to be expandable, an

A flexible radially outer portion which merges together to provide a complete tubular wall structure, the flexible outer portion being less elastic than the inner portion to compliantly resist radial expansion of the inner portion, wherein

The flexible, radially outer portion further comprising an outer tube of fiber reinforced composite construction surrounded by a flexible outer shell and further comprising a reinforcement and an adhesive;

a space exists between the inner portion and the outer portion, an

Wherein gas present in the space is exhausted when the interior is expanded.

21. The elongated hollow structure of claim 20 wherein the outer portion is configured as an outer tube of fiber reinforced composite construction surrounded by a flexible outer sheath.

22. An elongate hollow structure as claimed in claim 21 wherein the fibre reinforced composite construction comprises one or more layers of reinforcing fabric, each layer being configured as a tubular layer arranged around the interior.

23. The elongated, hollow structure of claim 22 wherein the reinforcing fabric comprises a reinforcing fabric comprising reinforcing fibers having a tetraxial fiber orientation characteristic.