Patent Publication Number: US-10774950-B2

Title: Layer repair

Description:
The present invention relates to a method and apparatus for at least partially repairing a tubular composite layer. In particular, but not exclusively, the present invention relates to the repair of a composite layer using independently moving abutment elements which can be urged against an outer surface of the composite layer at desired pressures and temperatures where defects have been identified to help correct those defects. 
     Traditionally flexible pipe is utilised to transport production fluids, such as oil and/or gas and/or water, from one location to another. Flexible pipe is particularly useful in connecting a sub-sea location (which may be deep underwater, say 1000 metres or more) to a sea level location. The pipe may have an internal diameter of typically up to around 0.6 metres (e.g. diameters may range from 0.05 m up to 0.6 m). Flexible pipe is generally formed as an assembly of flexible pipe body and one or more end fittings. The pipe body is typically formed as a combination of layered materials that form a pressure-containing conduit. The pipe structure allows large deflections without causing bending stresses that impair the pipe&#39;s functionality over its lifetime. There are different types of flexible pipe such as unbonded flexible pipe which is manufactured in accordance with API 17J or composite type flexible pipe or the like. The pipe body is generally built up as a combined structure including polymer layers and/or composite layers and/or metallic layers. For example, pipe body may include polymer and metal layers, or polymer and composite layers, or polymer, metal and composite layers. Depending upon the layers of the flexible pipe used and the type of flexible pipe some of the pipe layers may be bonded together or remain unbonded. 
     Some flexible pipe has been used for deep water (less than 3,300 feet (1,005.84 metres)) and ultra-deep water (greater than 3,300 feet) developments. It is the increasing demand for oil which is causing exploration to occur at greater and greater depths (for example in excess of 8202 feet (2500 metres)) where environmental factors are more extreme. For example in such deep and ultra-deep water environments ocean floor temperature increases the risk of production fluids cooling to a temperature that may lead to pipe blockage. In practice flexible pipe conventionally is designed to perform at operating temperatures of −30° C. to +130° C. Increased depths also increase the pressure associated with the environment in which the flexible pipe must operate. For example, a flexible pipe may be required to operate with external pressures ranging from 0.1 MPa to 30 MPa acting on the pipe. Equally, transporting oil, gas or water may well give rise to high pressures acting on the flexible pipe from within, for example with internal pressures ranging from zero to 140 MPa from bore fluid acting on the pipe. As a result the need for high levels of performance from the pressure armour and tensile armour layers of the flexible pipe body is increased. It is noted for the sake of completeness that flexible pipe may also be used for shallow water applications (for example less than around 500 metres depth) or even for shore (overland) applications. 
     Regardless of the type of flexible pipe body being manufactured, whenever a composite layer of flexible pipe body is to be manufactured defects can occur in the manufacturing step in which the composite layer is manufactured. For example voids caused by lack of fusion between successive windings of a tape and/or between adjacent layers or local regions of porosity caused by deficiencies in raw materials used can result in a composite layer containing one or more defects in one or more regions. Conventionally these defects can cause failure in any flexible pipe ultimately incorporating such layers and/or can involve time consuming and thus costly after the event analysis and remedial work. 
     During manufacturing of flexible pipe body various layers of pipe body are manufactured via a range of processing steps. For example polymer layers can be extruded or layers can be formed by consolidating wound tape or layers of polymer material can be deposited. Regardless of a manufacturing technique used, it is known that on occasion maintaining a desired shape in any cross section of the layer can be problematical. For example the roundness or ovality of a cross section of a layer should be maintained within predetermined desired limits. Ideally a cross section of a tubular layer should be perfectly circular. In practice according to conventional techniques some tubular layers have been susceptible to sagging which has led to an oval cross section being adopted over time. This can cause a problem when subsequent layers are manufactured over non-circular layers with a net result being that an end product, i.e. the flexible pipe body, does not have a desired shape. 
     It is an aim of the present invention to at least partly mitigate the above-mentioned problems. 
     It is an aim of certain embodiments of the present invention to provide a method and apparatus that can at least partially repair a defect in a tubular layer. 
     It is an aim of certain embodiments of the present invention to provide a method and apparatus that can automatically and continuously correct defects in one or more regions of a tubular composite layer. 
     It is an aim of certain embodiments of the present invention to provide a method and apparatus for repairing one or more defects at least partially or wholly, in a tubular composite layer that is continually moving at a line speed associated with a production line manufacturing the tubular composite layer. 
     It is an aim of certain embodiments of the present invention to provide a method and apparatus for partially or wholly repairing defect, in real time, in a layer of an unbonded flexible pipe as the layer is manufactured as part of a single production process. 
     According to a first aspect of the present invention there is provided apparatus for at least partially repairing a defect in a tubular composite layer, comprising: 
     a plurality of independently movable abutment elements each supported in a spaced apart relationship via a respective one of at least one support member; wherein each abutment element is associated with a respective drive axis along which the abutment elements are movable and the drive axes of all abutment elements extend outwardly from a common centre point. 
     Aptly each abutment element is selectively and independently drivable towards the centre point to provide a desired pressure to a region of an outer surface of a tubular composite layer having a longitudinal tube axis that extends through the centre point and substantially perpendicular to a plane defined by the abutment elements. 
     Aptly each abutment element comprises an abutment surface having a predetermined profile. 
     Aptly in a non-driven state, each abutment element is disposed at a neutral position a respective distance from the common centre point. 
     Aptly each abutment element is selectively drivable via a respective drive member towards the centre point from the neutral position or away from the centre point towards the neutral position. 
     Aptly the profile of each abutment surface is convex. 
     Aptly the profile of each abutment surface is concave. 
     Aptly each abutment element comprises a platen element or pin element or roller element. 
     Aptly the support member is transportable along a longitudinal support axis associated with a longitudinal tube axis of the tubular composite member. 
     Aptly the support member is bi-directional and is transportable along the support axis in an upstream or downstream direction. 
     Aptly the apparatus further comprises a plurality of support members each supporting a respective plurality of independently moveable abutment elements, said plurality of support members being spaced apart in a substantially parallel relationship. 
     Aptly the apparatus further comprises at least one heater element for selectively heating at least one of the abutment elements and/or a region of a tubular composite layer to a desired temperature. 
     Aptly the apparatus further comprises at least one cooler element for selectively cooling at least one of the abutment elements and/or a region of a tubular composite layer to a desired temperature. 
     Aptly the desired temperature is a fixed temperature or a varying temperature having a desired temperature profile. 
     Aptly the apparatus further comprises a heater element for each abutment element; wherein each heater element is independently controllable to selectively heat a respective abutment element independently. 
     Aptly the apparatus further comprises a cooler element for each abutment element; wherein each cooler element is independently controllable to selectively cool a respective abutment element independently. 
     Aptly the heater element selectively heats a respective at least one abutment element or region of tubular composite layer to a temperature of about around 120° C. to 250° C. 
     Aptly the selective heating is heating to about around 180° C. to 220° C. 
     Aptly each support member comprises a circular through hole and each abutment element supported by a respective support member is supported circumferentially around the through hole with a drive axis of each abutment element being aligned as per an imaginary radius extending from a centre of the through hole that corresponds with the common centre point. 
     Aptly the support member is located downstream of, an in-line configuration with, an inspection station that determines a type, size and/or location of a defect in a tubular composite layer; wherein
         the tubular composite layer is arranged to be transported through the support member.       

     Aptly a location of a central tube axis of the tubular composite layer as it passes through the support member coincides with the location of the common centre point. 
     Aptly each abutment element comprises a roller element having a substantially cylindrical or figure of eight shaped outer surface that rolls about a respective longitudinal roller axis. 
     Aptly the apparatus comprises a plurality of sets of roller elements, each roll element in each set having a similar shape and size and the size and/or shape in each set being different and being associated with a respective different possible size of tubular composite layer. 
     Aptly each abutment element comprises a platen element having a respective shaped contact surface. 
     Aptly the apparatus further comprises a plurality of sets of platen elements, each platen element in each set having a similar size and shape and the size and/or shape in each set being different and being associated with a respective different possible size of tubular composite layer. 
     Aptly the apparatus further comprises a drive member that selectively rotates the support member to align at least one abutment element with respect to a defective region of the tubular composite layer. 
     According to a second aspect of the present invention there is provided a repair station comprising a plurality of independently movable elements ach supported in a spaced apart relationship via a respective one of at least one support member; wherein
         each abutment element is associated with a respective drive axis along which the abutment elements are movable and the drive axes of all abutment elements extend outwardly from a common centre point.       

     According to a third aspect of the present invention there is provided a method for at least partially repairing a defect in a tubular composite layer, comprising the steps of;
         transporting a tubular composite layer proximate to a plurality of independently movable abutment elements supported in a spaced apart relationship via a respective one of at least one support member; and   selectively moving abutment elements along a respective drive axis that are aligned with a common centre point that corresponds with a location of a longitudinal axis of the tubular composite layer.       

     Aptly the method further comprises selectively urging the abutment elements against an outer surface of the tubular composite layer thereby providing a desired repair pressure at at least one region of the tubular composite layer. 
     Aptly the method further comprises providing the tubular composite layer via an extrusion station or a winding station or a deposition station, over an underlying substantially cylindrical surface and transporting the tubular composite layer proximate to the abutment elements in a single production run. 
     Aptly the method further comprises selectively moving the abutment elements responsive to a real time output indicating defects from an inspection station disposed upstream of and in line with the abutment elements. 
     Aptly the method further comprises applying a repair cycle to the tubular composite layer by selectively applying pressure to an outer surface of the tubular composite layer via the plurality of abutment elements as the tubular composite layer is transported in a single pass production run. 
     Aptly the method further comprises applying the repair cycle via a series of abutment element supports and respective abutment elements arranged sequentially along a transport path followed by the tubular composite layer. 
     Aptly the method further comprises selectively advancing each support member at a speed corresponding to a line speed associated with a production line for the tubular composite layer. 
     Aptly the method further comprises, subsequent to the support member being advanced by a predetermined distance, disengaging all abutment elements supported by the advanced support member from the tubular composite layer and driving the support member in a reverse direction to a respective repair starting position. 
     Aptly the method further comprises selectively heating at least one abutment element and/or a region of the tubular element. 
     Aptly the method further comprises selectively cooling at least one abutment element and/or a region of the tubular element. 
     Aptly the method further comprises, as part of the repair cycle, applying a fixed desired temperature or a varying temperature having a desired temperature profile to at least one region of the tubular composite layer. 
     Aptly the method further comprises at least partially repairing the defect by fusing together adjacent windings of tape that provide the tubular composite layer. 
     Aptly the method further comprises at least partially repairing the defect by fusing together material of successive tape layers, a preceding tape layer providing a sub layer over which a subsequent tape layer comprising the tubular composite layer is provided. 
     Aptly the method further comprises at least partially repairing the defect by closing pores in a region of the tubular composite layer. 
     Aptly the method further comprises at least partially repairing the defect by increasing or decreasing a layer thickness of a region of the tubular composite layer. 
     Aptly the method further comprises selectively rotating a support member to align at least one abutment element with a defective region of the tubular composite layer. 
     Aptly the method further comprises selectively rotating a set of abutment elements in a plane of a respective support member to align at least one abutment element with a defective region of the tubular composite layer. 
     Aptly the method further comprises determining a size associated with the tubular composite layer; and selecting a set of abutment elements associated with said a size responsive thereto. 
     According to a fourth aspect of the present invention there is provided a method of manufacturing flexible pipe body comprising the steps of at least partially repairing a defect in a tubular composite layer by the steps of, transporting a tubular composite layer proximate to a plurality of independently movable abutment elements supported in a spaced apart relationship via a respective one of at least one support member; and
         selectively moving abutment elements along a respective drive axis that are aligned with a common centre point that corresponds with a location of a longitudinal axis of the tubular composite layer.       

     According to a fifth aspect of the present invention there is provided apparatus constructed and arranged substantially as hereinafter described with reference to the accompanying drawings. 
     According to a sixth aspect of the present invention there is provided a method substantially as hereinafter described with reference to the accompanying drawings. 
     Certain embodiments of the present invention provide a method and apparatus for at least partially repairing a defect in a tubular composite layer. 
     Certain embodiments of the present invention provide an automated and continuous system for wholly or partly correcting defects which occur anywhere along a length of a tubular composite layer as that tubular composite layer is manufactured in an in-line production process. 
     Certain embodiments of the present invention provide an apparatus, for repairing defects, which receives, in real time, data indicating one or more regions of a tubular composite layer which may include defects and automatically and continuously applying pressure and/or heat and/or cooling to those potentially defective regions to wholly or partly repair defects. 
     Certain embodiments of the present invention provide a technique whereby defects in a tubular layer produced in an in-line continuous production process can be corrected as the production line continues in a single pass. That is to say conventional after the event analysis and remedial action is not needed and thus the production process can be continued without halt. 
    
    
     
       Certain embodiments of the present invention will now be described hereinafter, by way of example only, with reference to the accompanying drawings in which: 
         FIG. 1  illustrates bonded flexible pipe; 
         FIG. 2  illustrates uses of flexible pipe; 
         FIG. 3  illustrates a process flow map for a process of manufacturing a tubular composite layer; 
         FIG. 4  illustrates options for winding tape; 
         FIG. 5  illustrates winding tape from a supply reel to a storage spool; 
         FIG. 6  illustrates production of a continuous tape length; 
         FIG. 7  illustrates options for providing continuous tape to a tape spool for a winding carousel; 
         FIG. 8  illustrates a relationship with tape width and pipe diameter; 
         FIG. 9  illustrates rotational speed used versus pipe diameter; 
         FIG. 10  illustrates split spools; 
         FIG. 11  illustrates split spools; 
         FIG. 12  illustrates lifting of a spool; 
         FIG. 13  illustrates re-rounding; 
         FIG. 14  illustrates a re-rounding technique; 
         FIG. 15  illustrates a re-rounder; 
         FIG. 16  illustrates a touchdown point for tape wound over an underlying layer; 
         FIG. 17  illustrates consolidation of tape windings; 
         FIG. 18  illustrates alignment of tape with respect to a consolidation roller; 
         FIG. 19  illustrates guiding a pathway of tape; 
         FIG. 20  illustrates upstream pre-heating of a liner; 
         FIG. 21  illustrates pre-heating of a tape and pre-heating of a liner; 
         FIG. 22  illustrates power requirement for particular layer diameters; 
         FIG. 23  illustrates power requirement for different layer diameters; 
         FIG. 24  illustrates power requirement for different layer requirements; 
         FIG. 25  illustrates power requirement for different layer diameters; 
         FIG. 26  illustrates transient effects for convective heating of a pipe; 
         FIG. 27  illustrates pre-heating of incoming tape using infrared emitters; 
         FIG. 28  illustrates a laser based heating system; 
         FIG. 29  illustrates an alternative consolidation roller; 
         FIG. 30  illustrates an alternative consolidation roller; 
         FIG. 31  illustrates cooling of a consolidation roller; 
         FIG. 32  illustrates driving a reel and controlling production line tension; 
         FIG. 33  illustrates sensors and/or a support at an inspection station; 
         FIG. 34  illustrates detection of a void; 
         FIG. 35  illustrates detection of a void; p  FIG. 36  illustrates detection of a small void; 
         FIG. 37  illustrates detection of one or more regions of porosity; 
         FIG. 38  illustrates a tubular composite layer passing through a repair station; and 
         FIG. 39  illustrates abutment elements at a repair station. 
     
    
    
     In the drawings like reference numerals refer to like parts. 
     Throughout this description, reference will be made to a flexible pipe. It is to be appreciated that certain embodiments of the present invention are applicable to use with a wide variety of flexible pipe. For example certain embodiments of the present invention can be used with respect to flexible pipe and associated end fittings of the type which is manufactured according to API 17J. Such flexible pipe is often referred to as unbonded flexible pipe. 
     Likewise, and as described in more detail below, certain other embodiments of the present invention are usable with flexible pipe and associated end fittings for flexible pipe of a composite type structure. Such composite type flexible pipe and its manufacture is currently being standardised by the API. Such flexible pipe can include adjacent tubular layers that are bonded together. 
     Turning to  FIG. 1  it will be understood that the illustrated flexible pipe is an assembly of a portion of pipe body and one or more end fittings in each of which a respective end of the pipe body is terminated.  FIG. 1  illustrates how pipe body  100  is formed from a combination of layered materials that form a pressure-containing conduit. As noted above although a number of particular layers are illustrated in  FIG. 1 , it is to be understood that certain embodiments of the present invention are broadly applicable to coaxial pipe body structures including two or more layers manufactured from a variety of possible materials where at least one layer is a tubular composite layer. It is to be further noted that the layer thicknesses are shown for illustrative purposes only. As used herein, the term “composite” is used to broadly refer to a material that is formed from two or more different materials, for example a material formed from a matrix material and reinforcement fibres. Certain other possible examples are described herein below. 
     A tubular composite layer is thus a layer having a generally tubular shape formed of composite material. The layer may be manufactured via an extrusion, pultrusion or deposition process or, as described hereinafter, by a winding process in which adjacent windings of tape which themselves have a composite structure are consolidated together with adjacent windings. The composite material, regardless of manufacturing technique used, may optionally include a matrix or body of material having a first characteristic in which further elements having different physical characteristics are embedded. That is to say elongate fibres which are aligned to some extent or smaller fibres randomly orientated can be set into a main body or spheres or other regular or irregular shaped particles can be embedded in a matrix material, or a combination of more than one of the above. Aptly the matrix material is a thermoplastic material, aptly the thermoplastic material is polyethylene or polypropylene or nylon or PVC or PVDF or PFA or PEEK or PTFE or alloys of such materials with reinforcing fibres manufactured from one or more of glass, ceramic, basalt, carbon, carbon nanotubes, polyester, nylon, aramid, steel, nickel alloy, titanium alloy, aluminium alloy or the like or fillers manufactured from glass, ceramic, carbon, metals, buckminsterfullerenes, metal silicates, carbides, carbonates, oxides or the like. 
     The pipe body  100  illustrated in  FIG. 1  includes an internal pressure sheath  105  which acts as a fluid retaining layer and comprises a polymer layer that ensures internal fluid integrity. The layer provides a boundary for any conveyed fluid. It is to be understood that this layer may itself comprise a number of sub-layers. It will be appreciated that when a carcass layer (not shown) is utilised the internal pressure sheath is often referred to by those skilled in the art as a barrier layer. In operation without such a carcass (so-called smooth bore operation) the internal pressure sheath may be referred to as a liner. Such a liner  105  is illustrated in  FIG. 1 . 
     It is noted that a carcass layer where it is used is a pressure resistant layer that provides an interlocked construction that can be used as the innermost layer to prevent, totally or partially, collapse of the internal pressure sheath  105  due to pipe decompression, external pressure, and tensile armour pressure and mechanical crushing loads. The carcass is a crush resistant layer. It will be appreciated that certain embodiments of the present invention are thus applicable to ‘rough bore’ applications (with a carcass). Aptly the carcass layer is a metallic layer. Aptly the carcass layer is formed from stainless steel, corrosion resistant nickel alloy or the like. Aptly the carcass layer is formed from a composite, polymer, or other material, or a combination of materials. Aptly the carcass layer can be substituted for a bonded reinforcement layer outside of the internal pressure sheath, which also acts as a pressure armour layer  110 . 
     A pressure armour layer  110  is a pressure resistant layer that provides a structural layer that increases the resistance of the flexible pipe to internal and external pressure and mechanical crushing loads. The layer also structurally supports the internal pressure sheath. Aptly as illustrated in  FIG. 1  the pressure armour layer is formed from a tubular composite layer. Aptly for unbonded type flexible pipe (not shown) the pressure armour layer consists of an interlocked construction of wires with a lay angle close to 90°. Aptly in this case the pressure armour layer is a metallic layer. Aptly the pressure armour layer is formed from carbon steel, aluminium alloy or the like. Aptly the pressure armour layer is formed from a pultruded composite interlocking layer. Aptly the pressure armour layer is formed from a composite formed by extrusion or pultrusion or deposition or winding of layers of tape material wherein the layers of pre-impregnated composite tape, or alternate layers of composite tapes and polymer tapes are consolidated and bonded together and also bonded to the internal pressure sheath  105  together forming a bonded pipe body structure. 
     The flexible pipe body also includes an optional first tensile armour layer  115  and optional second tensile armour layer  120 . Each tensile armour layer is used to sustain tensile loads and optionally also internal pressure. Aptly for some flexible pipes the tensile armour windings are of metal (for example steel, stainless steel or titanium or the like). For some composite flexible pipes the tensile armour windings may be polymer composite tape windings (for example provided with either thermoplastic, for instance nylon, matrix composite or thermoset, for instance epoxy, matrix composite). For unbonded flexible pipe the tensile armour layer is typically formed from a plurality of wires. (To impart strength to the layer) that are located over an inner layer and are helically wound along the length of the pipe at a lay angle typically between about 10° to 55°. Aptly the tensile armour layers are counter-wound in pairs. Aptly the tensile armour layers are metallic layers. Aptly the tensile armour layers are formed from carbon steel, stainless steel, titanium alloy, aluminium alloy or the like. Aptly the tensile armour layers are formed from a composite, polymer, or other material, or a combination of materials. 
     Aptly the flexible pipe body includes optional layers of tape (not shown) which help contain underlying layers and to some extent prevent abrasion between adjacent layers. The tape layer may optionally be a polymer or composite or a combination of materials. Tape layers can be used to help prevent metal-to-metal contact to help prevent wear. Tape layers over tensile armours can also help prevent “birdcaging”. 
     The flexible pipe body also includes optional layers of insulation  125  and an outer sheath  130 , which comprises a polymer layer used to protect the pipe against penetration of seawater and other external environments, corrosion, abrasion and mechanical damage. Any thermal insulation layer helps limit heat loss through the pipe wall to the surrounding environment. 
     Each flexible pipe comprises at least one portion, sometimes referred to as a segment or section of pipe body  100  together with an end fitting located at at least one end of the flexible pipe. An end fitting provides a mechanical device which forms the transition between the flexible pipe body and a connector. The different pipe layers as shown, for example, in  FIG. 1  are terminated in the end fitting in such a way as to transfer the load between the flexible pipe and the connector. 
       FIG. 2  illustrates a riser assembly  200  suitable for transporting production fluid such as oil and/or gas and/or water from a sub-sea location  221  to a floating facility  222 . For example, in  FIG. 2  the sub-sea location  221  includes a sub-sea flow line  225 . The flexible flow line  225  comprises a flexible pipe, wholly or in part, resting on the sea floor  230  or buried below the sea floor and used in a static application. The floating facility may be provided by a platform and/or buoy or, as illustrated in  FIG. 2 , a ship. The riser assembly  200  is provided as a flexible riser, that is to say a flexible pipe  240  connecting the ship to the sea floor installation. The flexible pipe may be in segments of flexible pipe body with connecting end fittings. 
     It will be appreciated that there are different types of riser, as is well-known by those skilled in the art. Certain embodiments of the present invention may be used with any type of riser, such as a freely suspended (free, catenary riser), a riser restrained to some extent (buoys, chains), totally restrained riser or enclosed in a tube (I or J tubes).  FIG. 2  also illustrates how portions of flexible pipe can be utilised as a jumper  250 . 
       FIG. 3  illustrates a process for manufacturing a layer of a flexible pipe. The manufacturing system  300  includes a first reel  305  which is driven by a respective rim drive  307  at a respective first end of a production line. A further reel  310  is driven by a further rim drive  312  of the production line. These reels are driven selectively so as to move partially or fully constructed flexible pipe body forwards and backwards along a central axis of production  315 . A direction of production is defined according to a direction in which the flexible pipe body is transported in any single pass along the production line. A respective layer can be added per pass. Alternatively additional winding, rounding, consolidation and optionally inspection modules may be utilised to provide additional layers in one production operation. In  FIG. 3  a direction of production for a particular layer is shown which runs left to right. A first caterpuller unit  317  helps pull the partially or fully constructed flexible pipe body along the production axis  315  and the further caterpuller unit  320  is located at the further end of the production line to again help pull the fully or partially constructed flexible pipe body along the production line. The caterpullers can optionally be bidirectional or unidirectional. Tension in the part or fully constructed pipe body can be controlled. Aptly at least two caterpullers or tensioners are provided to grip pipe and help control line speed. These can be located as illustrated in  FIG. 3  or at other locations along a production line as will be appreciated by those skilled in the art. Each of the two tensioners illustrated in  FIG. 3  comprises three grip jaws (tracks) mounted at an angle of 120° to each other such that one track, the lowest, provides a horizontal surface onto which the pipe will be laid out and the other two can be respectfully retracted and returned to clamp onto the pipe. Tensioners may alternatively have two or four or more tracks if desired. The tracks are opened and closed hydraulically and are mechanically linked so that they open and close in synchronisation and that a centre line height of the pipe gripped within the tracks remain constant. If a pipe diameter decreases during running the tracks of each caterpuller can optionally follow the pipe to maintain a constant pressure on the pipe. Likewise if a pipe diameter increases the tracks are arranged to open at a pre-set pressure point. Aptly rotation of the tracks is powered in both directions electrically. 
     Aptly performance specifications for each caterpuller shown in  FIG. 3  are set out in Table 1 illustrated below. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Specification 
                 Notes 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 No of Tracks 
                 3 
               
               
                 Max pipe pull force (Te) 
                       6.35 (7 US tons)  
               
               
                 Track Contact Length 
                 1778 
               
               
                 Grip Force per track (kN) 
                 1.4~84.0 
               
               
                 Max Product Dia (mm) 
                 406 (19″)  
               
               
                 Min Product Dia (mm) 
                 76 (2″)  
               
               
                 Centre Line Height (mm) 
                 1200 
               
               
                 Max Line Speed (m/min) 
                 5 
               
               
                 Track Shoe Angle (Deg) 
                  152 (angle between the two faces  
               
               
                   
                 of each shoe in contact with  
               
               
                   
                 the pipe. 
               
               
                 Track Shoe Material 
                  Polyurethane (Shore hardness TBC) 
               
               
                 Track width 
                  140 mm (As per current designs) 
               
               
                   
               
            
           
         
       
     
     Certain embodiments of the present invention provide a method and apparatus for producing a bonded composite layer for a broad range of pipe diameters. This range is illustrated below in Table 2. It will be appreciated that other pipe diameters can be made. 
     
       
         
           
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Pipe 
                 Approx.  
                 Approximate  
               
               
                 I/D Range 
                 finished pipe  
                 weight finished  
               
               
                 (Inches) 
                 O/D (Inches) 
                 pipe (Kg/m) 
               
               
                   
               
             
            
               
                 3-4 
                 5-6 
                  75-125 
               
               
                 4-6 
                 6-8 
                 100-200 
               
               
                 6-8 
                  8-10 
                   
               
               
                  8-12 
                 10-12 
                   
               
               
                 10-12 
                 12-14 
                   
               
               
                 12-14 
                 14-16 
                 150-250 
               
               
                 14-16 
                 16-18 
               
               
                   
               
            
           
         
       
     
     The manufacturing system  300  illustrated in  FIG. 3  uses a winding station  322  such as a winding carousel to wind composite tape  325  onto a cylindrical surface formed by an underlying layer. Tape is provided to the winding carousel  322  from multiple spools  327   0-3 . Each tape spool  327  is provided with a respective feed supply of a continuous tape  328 . Aptly manufacturing a bonded composite layer makes use of a continuous tape feed  328 . 
     To achieve this, shorter lengths of composite tape are spliced together prior to being wound onto a tape storage spool. An optional re-winder  330  is utilised to help carry out this operation. Raw material  332  in the form of premade tape of fixed length is supplied in relatively short lengths and spliced together before storing on a storage spool  333 . In use a rewind/unwind unit  335  is used to wind these longer lengths of tape onto respective tape spools  327   0-3  for use at the winding carousel  322 . Aptly the winding station comprises an accumulator unit (not shown) which allows successive tape spools/tape lengths to be joined without arresting the production process. 
     In the system  300  illustrated in  FIG. 3  a re-rounder station  340  is utilised to control the tolerance in terms of ovality of an incoming underlying layer of flexible pipe body. That is to say the re-rounder can help round a cross section of an underlying layer so that a cylindrical outer surface provided by the underlying layer is substantially round. Aptly the re-rounder may be positioned anywhere before the tape winding provided that the incoming layer remains re-rounded until after the tape is applied. Aptly the underlying layer is a liner and the winding carousel provides tape that helps form an overlying pressure armour layer as a tubular composite layer. The re-rounder station  340  is optional. Aptly an additional re-rounder station (not shown) is provided downstream of a consolidation station  350 . 
     As illustrated in  FIG. 3  a tape consolidation station  350  is provided downstream of the winding station  322 . That is to say the consolidation station, which is an arrangement of associated equipment and control elements is located further along in a direction of transportation of the flexible pipe body as a particular layer is manufactured. The consolidation station  350  helps consolidate adjacent windings  325   a ,  325   b  of composite tape so that adjacent windings are consolidated together to form a tubular composite layer. It is to be noted that optionally the consolidation unit may alternatively or additionally consolidate a layer in the sense of consolidating tape in a most recently applied layer with the material of an underlying layer about which the tape is wound. Multiple winding and consolidation units may be included in series to help build up additional thickness of the tubular composite layer if desired. 
     As illustrated in  FIG. 3  the manufacturing system  300  also includes a non-destructive testing (NDT) inspection station  360 . This is located downstream of the winding carousel  322  and consolidation station  350 . The inspection station  360  includes one or more sensors and is arranged in an in-line configuration with the winding station  322  shown in  FIG. 3 . The winding station  322  and consolidation unit  350  provide a tubular composite layer and the inspection station  360  automatically and continuously determines if at least one parameter of the tubular composite layer satisfies a respective predetermined condition in one or more regions of the tubular composite layer as the tubular composite layer is transported through or near to the inspection station. The inspection station also provides a real time output which indicates at least one of a type, size and/or location or other such characteristic of any defect in the tubular composite layer as it is made. Aptly the inspection station senses if parameters are different from an expected ‘ideal’ and determines if a defect is present and what type that defect is. Multiple NDT stations may optionally be included in the production line to help and inspect each respective composite layer after it has been applied, or to help inspect repairs carried out at a post process repair station  370  (as described further herein after). 
     A post-process repair station  370  is shown in  FIG. 3  downstream of the inspection station  360 . The repair station  370  receives input control responsive to the output from the inspection station and includes heating and/or pressure and/or cooling elements which can be brought to bear on the regions of the tubular composite layer where a defect has been identified. As such the repair station  370  can entirely or at least partially help to correct the defects in real time and in an in-line single production process. This helps avoid the need for after the event analysis and subsequent remedial action. 
     As illustrated in  FIG. 3  a user interface  370  which includes a user display at an analysis and control station  380  can be utilised to control the parameters of the overall manufacturing system  300 . For example line speed and/or winding speed and/or consolidation temperatures and pressures and/or inspection techniques and/or re-rounding action and/or post process defect repair can be selectively controlled. 
     Manufacture of a continuous bonded composite layer for a flexible pipe requires a predetermined amount of raw material. Significant lengths of raw material in the form of tape for winding at a winding station can be used. Aptly the length of continuous tape wound in a winding station  322  is 500 m or more in length. As a result of this a re-wind operation can be utilised within a pipe manufacturing facility which makes use of the manufacturing system  300  illustrated in  FIG. 3 . Aptly the length of each tape used in a re-winding station  330  is about around 100 to 300 m. Aptly the length of each tape used in a re-winding station is about around 250 m. The re-winding process is optionally configured to supply tape directly into tape spools  327   0-3    FIG. 4  helps illustrate the re-winding process in which raw material from a manufacturer is provided from a spool  400  in the form of composite tape of a fixed relatively short length. Manufacturing a bonded composite layer requires a longer continuous tape feed. To help achieve this, lengths of composite tape provided as raw material on a spool  400  are spliced together at a splicing station  410  prior to being wound. Winding occurs either directly into the winding station/winding carousel  420  (illustrated as task  1 ) or optionally onto a tape storage spool in an off-line re-wind station (illustrated as task  2 ). It should be noted that tape may also be wound out of the winding station (illustrated as task  3 ) onto an external tape storage spool in order to remove left-over material at the end of any production run or in order to change materials/material properties of the tapes part way through a production run. 
       FIG. 5  helps illustrate the process of splicing shorter raw material lengths of composite tape together to form longer continuous tape lengths on a tape spool  420 . It may be noted that the receiving tape spool(s) may be on the production line  327   0-3  or off-line to be substantially fed onto the on-line spool(s). A supply wheel  400  of raw material is driven by/pulled from an adjustable brake/tension pay-off unit  500 . 
     This tape which is incoming from the supply reel  400  is guided by a guided roller  510  through a first clamp element  520  and is then fed between a joining press  530 . The joining press splices opposed ends of a preceding length of tape to a leading end of a new tape length. A further clamp  540  helps secure a trailing end of a preceding tape in position to be joined with the leading end of the new tape length. A further guide roller  540  is used to help guide the tape to the storage spool  420  which is driven by a drive and brake unit  560 . 
       FIG. 6  helps illustrate the joining press  530  shown in  FIG. 5  in more detail. The joining press  530  includes an upper heated plate  610  and opposed lower heated plate  620 . A leading end  630  of a new incoming length of composite tape is located juxtaposed with a trailing end  640  of a previously provided length of tape. By urging the two opposed heated plates together at a desired temperature two shorter lengths of tape can be extended in length. By repeatedly carrying out this process multiple shorter lengths of tape can be secured together to effectively provide a continuous tape feed. This process can be automated by using sensors not shown to identify and align tape ends. Optionally, of course, suitable large lengths of needed tape can be supplied in which situation the joining of shorter lengths is not necessary. 
     Aptly in order to help minimise a movement of raw material to and from a tape winding carousel the re-winding operation is located proximate to the winding station. The re-winding unit is also capable of servicing multiple tape modules. This is illustrated in  FIG. 7  which illustrates how a tape storage zone  700  can be used to store incoming supply reels from manufacturers and how these can be loaded in an automated or at least semi-automated way onto a re-winder positioned at a desired location shown as a first and second location  710   0 ,  710   1  which can then be used to refill a respective storage spool  420  (either off-line or in-line) for a specific composite tape prior to provide a continuous tape to a particular tape spool that feeds the winding station. The storage spool and/or re-winder unit move selectively along respective rails  720 ,  730  to align re-winders and storage spools and/or tape spools  327   0-3  supply the winding carousel  322 . 
     Aptly the storage zone can house both empty and loaded tape spools. Aptly the facility is able to store multiple different sizes of spools. Aptly the storage zone is a region close to the winding station that provides access to a spool via an overhead crane. 
     Manufacturing of a bonded composite layer requires a tape of predetermined width, thickness and length. Aptly multiple spools, each designed and manufactured for use with a specific tape width and storage capacity are provided. Tape storage spools can be provided for tape widths of 10 mm, 20 mm, 60 mm and/or 80 mm or the like. 
       FIG. 8  illustrates a relationship with tape width and nominal pipe diameter for a total tape width which produces a single cover in one path for target angles of 80°, 83° and 85°. A nominally 8″ pipe at 83° requires a tape width of 80 mm for a single cover. Aptly this is split into two strands at 40 mm or four strands at 20 mm to achieve the same cover but with corresponding numbers of tape heads. 
       FIG. 9  helps illustrate a rotational speed used to produce a single cover at 1 m/min linear speed versus pipe diameter. Speed remains constant if a single tape is used or the tape is split into two or four. The difference is that of heat input which can optionally be applied through several tape heads. 
     Using the re-winder, raw material is wound onto the tape storage spools offline prior to commencing production. The spools are capable of accommodating a number of tape widths as previously mentioned. In addition, spools are optionally designed so that they can be split into two halves. This is illustrated in  FIGS. 10 and 11  in more detail. As illustrated a splittable spool  1200  includes a first portion  1210  illustrated as a top portion in  FIG. 10  and a further portion  1220  illustrated as a bottom portion in  FIG. 10 . Should the occasion/need arise, this allows for spools to be unwound and removed or loaded and rewound in use whilst a pipe is running through a centre of the carousel. The split spools  1200  illustrated in  FIGS. 10 and 11  can thus be utilised as the tape spools  327   0-3  illustrated in  FIG. 3 . Aptly a multi-part can be separated into more than two parts. Aptly the spool is provided with lifting points to allow loading or unloading of either a full spool or half section using an overhead crane.  FIG. 12  helps illustrate how optionally a rim  1300  of a spool can be formed so as to form a channel  1310 . The channel which can be continuous around a whole circumference of a spool or optionally is only located in particular locations can be engaged by a mating lifting hook  1320  of a lifting crane and used as a lifting point. Other lifting mechanisms could of course be used on a spool. 
     To help improve a tape laying process and ensure good concentricity of the pipe prior to tape laying, a method of re-rounding the existing layer or layers of flexible pipe body can optionally be utilised. Aptly a re-rounding station  340  can be utilised immediately before a tape consolidation step.  FIG. 13  helps illustrate how a re-rounder can be utilised to provide a variable pressing force (illustrated by arrows F) at selected locations around a circumference of a cross section of a tubular layer such as a liner or a liner and overlying tubular composite layer or the like. Aptly a re-rounder is utilised for pipe structure re-rounding when no carcass is present. Aptly the re-rounder is able to re-round a tubular layer having an outer diameter of between 2″ and 19″. Aptly the re-rounder is able to re-round tubular layers having an outer diameter of between 6″ and 16″. The re-rounder is capable of exerting a force or pressure uniformly on the outer circumference to achieve a pre-set ovality tolerance. 
       FIG. 14  helps illustrate the action of a re-rounder  1500  at a re-rounder station  340 . It will be appreciated that a re-rounder station includes the re-rounder together with ancillary equipment and control equipment to control operation of the re-rounder. As illustrated in  FIG. 14  the re-rounder can be provided by a compressive dye  1510  that can be provided circumferentially around an outer surface of a tubular layer at a fixed position with respect to a direction of production. Aptly the dye material is of low friction (for instance PTFE or the like) and the contact surface is smooth so that the progress of the tubular layer is not adversely inhibited, nor damaged by the re-rounding process. 
       FIG. 15  illustrates an alternative re-rounder  1600  which includes six rollers  1610   0-5  which have a generally figure of eight shaped outer running surface which has a concave shape with an arc corresponding to the shape of an outer surface of the flexible pipe layer being rounded. In  FIG. 15  the tubular layer/pipe being re-rounded runs in and out of the page. The circumferential position of rolls may be rotatably positioned and aligned with ovality based on measurements from a previous inspection station. Each roller rolls along a respective longitudinal axis and is supported by a roller support  1620   0-5  which is spring loaded via a respective spring  1630   0-5 . The spring is a biasing element that biases a respective roller constantly against the outer surface of the tubular layer. Alternatively the rollers can be hydraulically driven or pneumatically driven or are otherwise actuated. Sets of rollers suitable for certain pipe size ranges may optionally be configured into the same re-rounder tool so that they can be rotated or otherwise moved in and out of position to act on a respective size of pipe in use at that moment in time. A result of this set up is to reduce the time required to change from one pipe diameter to another. 
       FIG. 16  helps illustrate the touchdown point by the winding carousel of the winding station  322  in more detail. The touchdown point  1700  is the location on a cylindrical outer surface of an underlying substantially tubular element at which incoming continuous lengths of tape touch the outer surface of the underlying cylindrical surface. For example, as illustrated in  FIG. 16  an incoming tape  325  is wound off a respective tape spool  327  and is transported in a direction illustrated by the arrow A. The tape  325  is duly located between a pair of opposed rollers  1710  which nip the tape. One or more of the rollers is driven so as to provide a desired tape tension. One or more heaters (not shown) can be located upstream and/or downstream of a pair of opposed rollers  1710  to pre-heat the incoming tape to a desired temperature. The tape is then fed along a tape supply pathway to a point between a cylindrical outer surface provided by a liner and an opposed consolidation roller  1720 . A consolidation force is supplied to the consolidation roller by a biasing element which in the example described is a spring or may optionally alternatively be a hydraulic or pneumatic actuator (not shown). This consolidation force is continuously controlled and monitored via the control station  380 . 
     As illustrated in  FIG. 16  a longitudinal axis associated with the roller is substantially aligned in a parallel offset fashion with a longitudinal axis associated with the liner  105 . One or more heaters and/or coolers (not shown) are arranged around the liner so as to pre-heat the liner material to a predetermined temperature prior to the touchdown of tape. One or more heaters and/or coolers are also located so as to be able to control the nip point temperature. That is to say a temperature at the point where tape touches down onto the outer surface of the liner. The continuous length of tape  325  is thus unwound from a storage spool and directed along a set path to the touchdown point on the pipe. To achieve good tape consolidation various parameters can be controlled along the route. These parameters include but are not limited to tape tension, tape angle, tape pre-heat temperature, tape gap, heated consolidation temperature, liner pre-heat temperature and consolidation force. Aptly tape tension is varied from 10 N to 200 N. Aptly a default tolerance on the set tape tension is plus or minus 3 N. Aptly a wrap angle of between about around 55° to 90° is utilised. A live adjustable closed loop system with feedback to control and monitor tape tension can optionally be included. Aptly a consolidation force is varied from about around 5 N to 400 N with a default tolerance on any predetermined pre-set value of plus or minus 3 N. A live adjustable closed loop system with feedback to control and monitor consolidation force can optionally be utilised. A tape wrap angle of between about around 55° to 90° can be used. Individual tooling can optionally be provided in 5° increments to allow manufacturing of tape angles across this range. Aptly each set of tooling can be provided to allow fine adjustments of plus or minus 3°. 
       FIG. 17  helps illustrate how a gap between adjacent tape windings can be controlled as the tape is wound. It will be understood that the underlying cylindrical surface, provided by an outer surface of the liner in the example shown in  FIG. 17 , is continually moving in a production direction illustrated by the arrow P in  FIG. 17 . Aptly the line speed in the production direction is about around 0.25 to 2 m/min. Aptly the line speed is about around 1 m/min. As the underlying layer advances, new tape winding, which is constantly wound helically around the cylindrical surface of the underlying layer by the rotating winding carousel, likewise advances so that on a next pass around the underlying layer a newly incoming winding abuts in a side-by-side arrangement with an immediately preceding winding. Aptly no overlap occurs between adjacent windings. Aptly adjacent edges of adjacent side-by-side windings abut. Aptly a gap  1800  of about around 0-50% of the tape width is left between tape windings  1810   0 -4 during the wrapping process. Aptly a gap  1800  of about around 0-1 mm of the tape width is left between tape windings  1810   0-4  during the wrapping process. 
     To help protect the incoming tape and ensure good consolidation is achieved the path from the spool to the touchdown point on the pipe illustrated in  FIG. 16  is kept within predetermined tolerances. Changes in direction along the tape path are likewise kept within predetermined tolerances. Where a change in direction takes place the change is made gradually so as to not damage the tape. Aptly the pathway followed by the incoming tape is constantly monitored and controlled to help keep the tape travelling along a centre line of the nip rollers  1710  and/or the consolidation roller  1720 .  FIG. 18  helps illustrate an underside view of the consolidation roller  1720  which rolls along a respective axis R.  FIG. 18  helps illustrate a tape axis T and helps illustrate how this tape axis T is kept aligned with a generally central position of the consolidation roller  1720 . 
       FIG. 19  helps illustrate how, in order to help maintain the incoming tape  325  on a predetermined pathway, one or more supply rollers such as the opposed rollers  1710  illustrated in  FIG. 16  can be provided with a guide groove  2000 . This guide groove is provided at a desired location on an outer running surface  2010  of one or more rollers at a predetermined location. Aptly, as illustrated in  FIG. 19 , the groove is located circumferentially around a centre region of a supply roller. As a result incoming tape  325  nests wholly (or at least partially in other examples) in the groove and is thereby located by the groove to keep the tape on a predetermined path as it advances towards the winding carousel. 
     Aptly a tape break alarm can be provided to alert machine operators that a break has occurred in a tape supply. The alarm can optionally be installed along each tape path between a respective spool and a respected touchdown point on the pipe line. The tape break alarm is aptly linked to a closed loop system monitored by the control station  380  so that action can be promptly taken to stop a manufacturing process and initiate remedial action if a tape break event occurs. Aptly a monitor for monitoring the amount of material being unwound from any spool or by the winding carousel can be provided. Information from such a monitor is used to generate a display on the display of the control station so that an operator can constantly watch one or more parameters of production. Aptly an amount of material unwound is converted and displayed as a measurement of linear metres of pipe made on the user interface. 
     As previously described the liner and/or tape can be pre-heated or immediately post heated to help during a consolidation process.  FIG. 20  helps illustrate this process in more detail. 
     Pre-heating helps reduce the operating requirements of the heating technology immediately prior to/during consolidation, (hence the power required by the consolidation heating system and/or total heat energy (and time) required to raise and maintain the temperature of the composite material during/to allow consolidation to be effective, is reduced). Aptly pre-heating is carried out as close to a tape consolidation area as possible. Aptly the liner is pre-heated to between about around 50° C. to 100° C. Aptly the liner is pre-heated to between about around 40° C. to 90° C. Aptly the tape is heated to about around 30 to 160° C. Aptly the tape is heated to about around 100 to 140° C. As illustrated in  FIG. 20  as the liner  105  advances in the direction of production P and the consolidation roller  1720  urges incoming composite tape  325  onto the outer surface of the liner the incoming liner upstream of the touchdown point can be pre-heated by a heating element. As illustrated in  FIG. 20  an induction heating coil  2100  can be used which is located surrounding the incoming liner. This can be used to continuously pre-heat the liner as it is transported along in the production direction P towards the supply point where composite tape is supplied onto the outer surface of the liner and urged against the outer surface by the constantly biased consolidation roller  1720 . 
       FIG. 21  helps illustrate pre-heating of tape prior to the touchdown point and heating of a liner using infrared techniques in more detail. As illustrated in  FIG. 21  a pre-heating unit  2200  is an example of a heating element which can be used between the nip rollers and the touchdown point  1700 . This pre-heating unit can include a single heating element or multiple heating elements to pre-heat incoming tape to a desired temperature. Likewise liner pre-heating can be provided in the form of two (other numbers are of course possible) infrared heaters  2210   0 ,  2200   1  which are directed to desired locations to heat a liner. The heaters move in a circular direction with the rotating winding carousel so as to heat the liner before the consolidation roller, which is constantly revolving as part of the winding carousel around the outer circumference of the liner, to a desired temperature. 
     To help consolidate thermoplastic composite tape one or both of the tape and the substrate are heated to a melting point of the thermoplastic material used. Aptly for the tape which is a composite material, the tape if heated to the melting point of the thermoplastic matrix material of the tape. Aptly to help achieve this and bearing in mind that there is a linear line speed of about around 1 m/min likely for the underlying liner, a pre-heating step is utilised prior to tape application. This helps reduce a requirement for energy input at a tape head region. 
     Aptly the incoming tape is a composite material comprising a carbon fibre reinforced PVDF tape. Pre-heating requirements for tapes having a 0.2 mm and 0.4 mm thickness for such tape is illustrated in  FIG. 22  and  FIG. 23 . As the tapes are relatively thin these figures illustrate heating from both sides of a tape to an even temperature.  FIGS. 22 and 23  are based upon a pipe line speed of 1 m/min and provide an indication of energy required to heat a full thickness of tape. Aptly this is a minimum power provided. Aptly two or three times this power is provided according to a type of heater utilised.  FIGS. 22 and 23  illustrate energy input for a single tape producing a complete cover.  FIG. 22  illustrates a power requirement to heat a 0.2 mm thick tape to 100° C., 120° C. or 140° C. versus pipe layer diameter.  FIG. 23  illustrates a power requirement to pre-heat a 0.4 mm thick tape to 100° C., 120° C. or 140° C. versus pipe layer diameter. 
     The substrate upon which the tape is wound is optionally pre-heated. In the instance in which the substrate is a liner which is relatively thick this presents a larger thermal mass than the incoming tape. Aptly this is heated from an outside region. Aptly heating occurs from the surface and through into the thickness of the liner to a predetermined depth. Aptly the heating depth is between about around 0 and 2 mm in depth. Aptly the heating thickness is about around 1 mm in depth. Heat input is controlled to help minimise residual stresses in a resulting structure. 
       FIG. 24  helps illustrate an order of magnitude calculation of a power requirement to pre-heat a PVDF liner assuming only a first outer 1 mm of thickness is heated to a uniform temperature. Energy requirement is shown to heat a whole outer surface of a liner moving at a line speed of 1 m/min.  FIG. 24  thus helps illustrate power requirement to pre-heat an 8 mm PVDF liner to 100° C., 120° C. or 140° C. versus pipe outer diameter. 
     Pre-heating of consolidated tape requires less power as illustrated in  FIG. 25 . This illustrates pre-heating energy input under similar assumptions to the liner noted above but for an 8 mm thick liner with 6 mm of consolidated tape on the outside. 
       FIG. 26  helps illustrate transient effects for convective heating of a pipe arrangement having an 8 mm liner and 6 mm composite tape at 200 mm nominal diameter. The transients are also illustrated for the condition in which a pipe is moving at 1 m/min and this passes through a heater which raises surface temperature to 126° C. within 30 seconds, approximately 0.5 mm below the surface the temperature is 100° C. and as time progresses the heat dissipates within the structure. 
     Pre-heating thermoplastic composite tape utilises a relatively low power of about around 0.5 kW whilst a liner of consolidated composite pipe surface requires a power arranged around the pipe of about around 3 to 4 kW over the above-mentioned range of pipe sizes. Aptly an infrared heating system can be utilised for composite tape consolidation. Infrared emitters provide adequate consolidation whilst being relatively cost effective and simple to utilise. Aptly as an alternative a laser heating system or the like can be utilised.  FIG. 27  helps illustrate pre-heating of incoming tape by infrared emitters. Use of such infrared emitters as a heating source helps reduce a requirement for installation space for additional emitters at a nip point area. 
       FIG. 28  illustrates a heater element in the form of a laser system  2900 . Such a system can provide a good consolidation for a bonded composite layer. Aptly a compact laser diode module device is used as the laser heating element  2900 . Aptly the laser heating system includes a cooling supply for a laser source and associated optics. Aptly the laser heater element is water cooled having a water pressure which does not exceed 6 bar and having a water flow of about around 101/hr. An air purge can optionally be applied to help avoid dust contamination in a pathway of the heating laser beam. Since the laser can provide significant heating capacity the consolidation roller may optionally include cooling to help prevent the roller from overheating. 
     A cross section of process requirements for different tape widths and materials is illustrated below in Table 3. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Tape Width and Material 
                 Output Power (Watts) 
               
               
                   
                   
               
             
            
               
                   
                  1 mm width of PA12/PVDF Tape 
                 240-308 
               
               
                   
                 20 mm width of PA12/PVDF Tape 
                 4.800-6.160 
               
               
                   
                 80 mm width of PA12/PVDF Tape 
                 19.200-24.640 
               
               
                   
                   
               
            
           
         
       
     
     Table 3 helps illustrate pre-heating and nip point power required for achieving process temperature. 
       FIGS. 29 and 30  illustrate views of a consolidation roller. The consolidation roller  1720  presses heated tape onto an underlying layer and helps consolidate adjacent windings together and/or ensures a good bond is achieved between each successive layer of tape windings. Aptly the roller is a light weight roller manufactured from a material with low heat capacity and high thermal conductivity. Aptly the roller is covered in a non-stick material. 
     Aptly the non-stick material is rubber based. Aptly rollers covered in approximately 10 mm thick layers of silicone or viton with a shore hardness of about 60 are used. Aptly the rollers are PTFE coated rollers with a coating thickness of approximately 40 microns plus or minus 10 microns. Aptly a solid PTFE bar can be used as a roller.  FIG. 29  illustrates a silicon based roller and  FIG. 30  illustrates an alternative solid PTFE consolidation roller. 
       FIG. 31  helps illustrate how a surface temperature of the roller can be maintained or “chilled” to below about around 120° C. This helps ensure tape fibres or resin does not adhere to a rolling surface of the roller. It will be appreciated that other ways of ensuring non-adherence can be utilised. As illustrated in  FIG. 31  an inlet port  3100  is utilised to receive a supply of cooling fluid which then circulates in a central region  3110  inside the body of the roller. A further outlet port  3120  is provided at a remaining end of the roller and coolant fluid exits through this outlet port  3120 . Coolant fluid is constantly circulated or alternatively provided in a one way direction.  FIG. 31  also helps illustrate how a lower rolling surface  3130  rolls along a radially outer surface  3140  of an incoming tape winding  325 . 
       FIG. 32  illustrates how tension in the production line can be maintained within predetermined tolerances.  FIG. 32  illustrates the reel  305  and corresponding rim drive  307  illustrated in  FIG. 3  in more detail and illustrates how a light curtain  3200  can be utilised to maintain a speed and tension at a desired level in the manufacturing line. 
     Table 4 illustrates how certain manufacturing process parameters can be controlled. Likewise Table 5 illustrates how certain alarms can be provided in the system so that an audible and/or visual cue is in initiated when a pre-set level for a particular parameter differs by more than a respective predetermined tolerance level. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Inputs 
               
            
           
           
               
               
               
            
               
                   
                 Parameter 
                 Required Sensing Range 
               
               
                   
                   
               
               
                   
                 Consolidation Force Set point 
                 0-400N  
               
               
                   
                 Consolidation Temp Set point 
                   0-700° C. 
               
               
                   
                 Caterpullar Speed Set point 
                     0-5.0 m/min 
               
               
                   
                 Caterpullar Clamping Pressure  
                 To be confirmed after discussions 
               
               
                   
                 Set point 
                 with supplier 
               
               
                   
                 Winding Rate Set point 
                     0-5.0 m/min 
               
               
                   
                 Tape Tension Set point 
                 10N-200N 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Alarms 
               
            
           
           
               
               
               
            
               
                   
                 Parameter 
                 Default Tolerance 
               
               
                   
                   
               
               
                   
                 Consolidation Force 
                 ±3N 
               
               
                   
                 Consolidation Patch Temp 
                   ±5° C. 
               
               
                   
                 Consolidation Roller Temp 
                   ±5° C. 
               
               
                   
                 Caterpullar Speed 
                  ±2% 
               
               
                   
                 Winding Rate 
                  ±2% 
               
               
                   
                 Tape Tension 
                 ±3N 
               
               
                   
                   
               
            
           
         
       
     
       FIG. 33  helps illustrate the inspection station  360  in more detail. The inspection station is fixed in location with respect to a pipe production direction P. As illustrated in  FIG. 33  the inspection station  360  includes a support  3300  which supports multiple sensors  3310   0-x . It will be appreciated that the support illustrated in  FIG. 33  has a central opening through which the tubular composite layer formed over a liner (not shown) passes during a production run. According to alternatives the sensors and sensor support can be arranged to a side or sides of the tubular layer. Likewise alternatively the support can be bidirectional and can be driven backwards and forwards along a region of the tubular composite layer. The layer inspection station  360  thus includes at least one sensor which is located downstream of an in an in-line configuration with an extrusion station or pultrusion station or deposition station or as illustrated in  FIG. 3  a winding station for providing a tubular composite layer over an underlying substantially cylindrical surface via a continuous process. 
     The inspection station  360  is a non-destructive testing (NDT) station which is able to identify one or more regions in the tubular composite layer where a defect may have occurred during a consolidation/manufacturing process. Aptly the NDT station  360  is placed directly after the tape consolidation area. The NDT station locates and/or measures and/or defines and/or records surface and/or sub surface flaws/defects. The inspection station  360  is capable of scanning a broad range of pipe diameters at a linear speed of approximately 1 m/min. 
     Depending upon the sensors used the sensors will detect conditions which cause attenuation or generate relevant intermediate echoes from an ultrasonic signal or other such probe signal. Aptly these conditions may be one or more of the following occurring during production: longitudinal delamination/voids and/or circumferential delamination/voids and/or local porosity in CFRP tape and/or porosity in tape-tape interfaces and/or surface/thickness profiling. Additionally techniques and sensors can be provided to help identify defects and damage caused by handling and pipe winding such as crush/impact damage and/or delamination at CFRP-liner interface and/or delamination at tape-tape interfaces and/or resin matrix micro cracking. Production tolerances can be pre-set using electronic gates. Triggering of these gates activates an audible and/or visual cue which is relayed to the control station  380 . 
     The sensors  3310  illustrated in  FIG. 33  are ultrasonic non-destructive testing sensors. 
     Such ultrasonic testing (UT) sensors can be used to determine a thickness of material and determine a location of a discontinuity within a part of the tubular layer. A discontinuity can be indicative of a defect. Aptly the sensors operate in the range of 500 kHz to 20 MHz. Aptly the sensors use pulse echo testing methods using single crystal probes or groups of single crystal probes or a phased array. The sensors thus send a pulse of ultrasound into a composite part proximate to where the sensor is located. A signal from a far side of the laminate material (referred to as a backwall echo) and other echoes that may be reflected from defects (referred to as an intermediate echo) are detected and measured. 
       FIG. 34  illustrates an optional test using ultrasonic pulse testing to produce an amplitude trace referred to as an “A-scan”.  FIG. 34  helps illustrate a backwall echo  3400  reflected from a far side of a laminate that is correctly manufactured. As the sensor  3310  moves with respect to the tubular composite layer (shown in  FIG. 35  by relative motion of the sensor  3310  into the middle of the figure where a defect  3500  is located) a pulse echo reflection from such a void shows production of an intermediate echo  3500  and loss of a backwall echo. 
       FIG. 36  illustrates an alternative defect  3600  which is a relatively small void  3600  smaller in size than an associated transducer diameter. As a result a reduced intermediate echo  3610  and a reduced backwall echo signal  3620  are detected. The detected intermediate and backwall echoes or absences of them and timings with respect to initial pulses can be used to determine a size and nature of a defect. 
       FIG. 37  helps illustrate how UT sensors  3310  can be utilised to detect a location of porous regions  3700  in a defective region dl of a tubular composite layer. Regions of porosity are determined by detecting scattered echoes  3700  of an initial pulse from one or more porous regions together with a reduced backwall echo signal  3710 . 
     Optionally B-scan pulse echo tests which show backwall echo reflected from a far side of a tubular composite layer can be utilised. B-scan inspection provides coverage along a desired length of pipe. Adequate coverage around a pipe circumference can be provided by use of multiple probes or by mechanical translation of the probes as the tubular composite layer is manufactured. As illustrated in  FIG. 33  two sets of four sensors can be utilised to monitor for a pipe condition. Effectively this produces information indicating regions of the tubular composite layer where a defect has occurred. Aptly outputs from the multiple sensors which each provide a respective probe are multiplexed to provide for real-time monitoring of the tubular composite layer. This permits backwall echo, wall thickness and B-scan data or other such probing parameters for each channel to be recorded and analysed in real time. Aptly ultrasonic data is collected and made available on the display of the control station  380 . Production tolerances can be pre-set and triggering at pre-set levels can activate an alarm if a determine defect has characteristics making it too significant to ignore. 
     Aptly a portable phased array equipment is utilised to perform localised inspections of pipe off-line in addition to a main NDT inspection process. 
     Table 6 illustrates some of the defect types which can optionally be detected and minimum sizes which can be accommodated. Minimum defect size is stated in Table 6 in terms of linear length (L) along the pipe and a fraction of the pipe circumference (C). 
     
       
         
           
               
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
               
                 Type of 
                 Min Defect Size 
                   
                   
               
               
                 Indication and Cause 
                 L × C 
                 Detection Method 
                 Limitations 
               
               
                   
               
             
            
               
                 Void caused by lack of 
                 50 mm × 0.25° C. 
                 Detection of intermediate 
                 Narrow linear indications 
               
               
                 fusion between successive 
                   
                 echo and/or loss of 
                 may not be detected if 
               
               
                 tape layers 
                   
                 backwall echo 
                 they are less than 25% of 
               
               
                   
                   
                   
                 pipe circumference 
               
               
                 Void caused by irregular 
                 50 mm × 0.25° C. 
                 Detection of intermediate 
                 Narrow linear indications 
               
               
                 consolidation around pipe 
                   
                 echo and/or loss of 
                 may not be detected if 
               
               
                 circumference 
                   
                 backwall echo 
                 they are less than 25% of 
               
               
                   
                   
                   
                 pipe circumference 
               
               
                 Clusters of small voids 
                 50 mm × 0.25° C. 
                 Detection of intermediate 
                 Cluster analysis required 
               
               
                   
                   
                 echo and/or reduction in 
                 relating number of 
               
               
                   
                   
                 backwall echo 
                 individual small voids and 
               
               
                   
                   
                   
                 spacing between them 
               
               
                 Porosity caused by local 
                 50 mm × 0.25° C. 
                 Reduction in backwall 
                 Relationship between 
               
               
                 porosity in raw tape 
                   
                 echo of 75% (12 dB). 
                 backwall echo, void 
               
               
                 product 
                   
                   
                 content and MKDF needs 
               
               
                   
                   
                   
                 to be established 
               
               
                 Porosity caused by poor 
                 5 mm × 0.25° C. 
                 Reduction in backwall 
                 Relationship between 
               
               
                 consolidation between 
                   
                 echo of 75% (12 dB). 
                 backwall echo, void 
               
               
                 successive tape layers 
                   
                   
                 content and MKDF needs 
               
               
                   
                   
                   
                 to be established 
               
               
                 Increase in thickness 
                 More than + 
                 Detection of backwall 
                 Effect of liner velocity and 
               
               
                 caused by resin richness, 
                 10% of nominal 
                 echo position 
                 thickness needs to 
               
               
                 under consolidation, over 
                 thickness 
                   
                 accounted for 
               
               
                 thick tape 
                   
                   
                   
               
               
                 Reduction in thickness 
                 More than 
                 Detection of backwall 
                 Effect of liner velocity and 
               
               
                 caused by resin starvation, 
                 −10% of 
                 echo position 
                 thickness needs to 
               
               
                 over consolidation, over 
                 nominal 
                   
                 accounted for 
               
               
                 thin tape 
                 thickness 
               
               
                   
               
            
           
         
       
     
     Aptly further details of the NDT system are set out in Table 7. 
     Software for the NDT system is provided which can include one or more of the following functions: B-scan cross-section data function of probe position and/or gating of A-scan data to produce backwall echo amplitude and thickness profiles and/or sizing tools with geometry correction and/or charting tools showing indications as a function of pipe length. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 NDT Station Configuration Summary 
               
            
           
           
               
               
               
            
               
                   
                 Parameter 
                 Details 
               
               
                   
                   
               
               
                   
                 No. of Probes 
                 4 (Expandable up to 64) 
               
               
                   
                 No. of Channels 
                 4 (Expandable up to 64) 
               
            
           
           
               
               
               
               
            
               
                   
                 Probe Diameter 
                 12  
                 mm 
               
               
                   
                 Probe Frequency 
                 1  
                 MHz 
               
            
           
           
               
               
               
            
               
                   
                 Coupling Agent 
                 Water bubbler/nylon delay line 
               
            
           
           
               
               
               
               
            
               
                   
                 Probe Standoff 
                 25  
                 mm 
               
               
                   
                 Max prf rate 
                 20  
                 KHz 
               
               
                   
                   
               
            
           
         
       
     
       FIG. 38  illustrates a repair station  370  in more detail. The repair station  370  is an example of a post process heating and/or cooling station if heating and/or cooling elements are provided. The repair station  370  is in-line and downstream of the inspection station  360  and receives as input and output from a preceding inspection station which provides a location and/or size and/or type of defect at one or more regions of the consolidated tubular composite layer. Should the UT scan from an inspection station  360  identify an area of the tubular composite layer which has not met a predetermined quality then immediate remedial action can be carried out by the repair station  370  without stopping a manufacturing process. Aptly the repair station  370  is placed within 100 metres of an NDT inspection station. Aptly the repair station  370  is placed immediately after an NDT inspection station (within 10 metres). Should the NDT scan identify an area of pipe which has failed to meet a quality required a gated alarm will initiate a procedure within the repair station  270  to locate and repair either surface or sub surface defect. The repair station  370  is capable of carrying out remedial work in real time on a broad range of pipe diameters and at a range of linear speeds of production. Aptly the repair station  370  is able to repair one or more defects simultaneously as a line speed of about around 1 m/min. As illustrated in  FIG. 38  the liner  105  and surrounding consolidated layer  110  which provides a tubular composite layer formed by consolidating adjacent windings of tape passes through a central orifice  3800  in a support  3810 . The support  3810  supports multiple moveable platens  3820  which are arranged circumferentially around the central circular opening  3800 . The support supports the moveable abutment elements  3820  in a manner which allows each abutment element  3820  to be independently moveable along a respective drive axis. This is illustrated more clearly in  FIG. 39 . As illustrated in  FIG. 39  a centre point C is associated with the central opening  3800  in the support  3810 . This centre point also corresponds with a central longitudinal axis of the liner  105  and consolidated composite layer  110 . This centre point C is common to the drive axis  3900   0-15  for the sixteen abutment elements  3820  illustrated in 
       FIGS. 38 and 39 . It will be appreciated that alternatively one, two or more abutment elements can be utilised. Utilising many (for example sixteen shown in  FIG. 39 ) abutment elements means that many locations on an outer surface of the composite layer can be pressurised and/or heated and/or cooled simultaneously. Fewer abutment elements can be utilised and optionally the support  3810  can be rotated by a driving mechanism (not shown) to help align abutment elements with defective regions of the tubular composite layer. Aptly in order to carry out corrective work, heat in the region of between 180° C. to 220° C., and a pressure of up to 4 MPa, can be applied for up to 1 to 2 seconds, locally to a defective region. To help ensure a bond between layers stays intact such pressure and heat is applied. Heat and/or pressure can be applied through the abutment elements  3820  using conduction to transmit the heat, or the heating can be applied separately with focused beams of energy (induction, convection, radiation) immediately prior to the abutment element applying pressure to the area. Aptly the temperature is measured and controlled using temperature sensors (optical pyrometers or the like) or a commercial optical temperature measurement system such as a thermographic imaging camera (e.g. Fluke TiR29 or the like). Aptly pressure can be applied through the abutment elements using hydraulic or pneumatic actuators. To help ensure layers stay intact overheating of tape during the post process heating can be avoided by providing cooling to a treated area immediately after treatment. Cooling to any desired region can be provided to reduce the temperature of that region to a temperature of about around 100° C. rapidly. Cooling can optionally be provided by additional cooling platens (conduction) or by directed cooling air currents (convection). 
     The abutment elements shown as platens  3820  in  FIG. 39  could alternatively be rollers or have other shapes. An abutment surface  3930  is provided on each platen. The abutment surface  3930  illustrated in  FIGS. 38 and 39  is convex. Alternatively other shapes such as concave shapes or figure of eight shapes can be utilised. The abutment surface can be urged against outward surface of the composite tape layer for a predetermined period of time and at a desired pressure and temperature to help consolidate porous regions or delaminated regions at locations previously determined in real time by the upstream inspection station. 
     Aptly thermal energy can be applied via various techniques to the surface or internally or by conduction or by convection and/or by radiation to regions of the pipe. Parameters such as cycle times and/or peak temperature and/or pressure/force application can be likewise applied. 
     The heating module provides real time information so that trends and failures can be recognised during and after post process heating. This helps support preventative strategies. 
     Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to” and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. 
     Features, integers, characteristics or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of the features and/or steps are mutually exclusive. The invention is not restricted to any details of any foregoing embodiments. The invention extends to any novel one, or novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. 
     The reader&#39;s attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.