End fitting for a composite pipe

Abstract

An end fitting assembly (601) for a composite pipe (610), the end fitting assembly having a spigot portion (602) and a ferrule portion (603). The spigot portion has a seal member arranged to seal the inner throughbore of the pipe at or toward the end of the pipe and in use the spigot portion is arranged to transfer axial force acting upon it to the ferrule portion. The ferrule portion comprises an axial length and has an inner throughbore and which is configured for fitment around an outer end region of the pipe. The end fitting assembly is arranged such that in use, pressure of fluid within the inner throughbore of the pipe acts on the inner throughbore of the pipe to create a greater frictional force between the outer surface of the pipe and the inner surface of the ferrule portion when compared with the axial force acting on the end fitting assembly such that the end fitting assembly is retained upon the pipe.

Description

[0001]END FITTING FOR A COMPOSITE PIPE FIELD The present application relates to an end fitting assembly for composite pipes, in particular but not limited to, a metallic end fitting assembly for high-pressure, thermoplastic composite pipes. BACKGROUND Conventionally, pipes and pipelines used to transport fluids (such as oil and gas and other hydrocarbons in the oil & gas / energy industry) have being manufactured from metal such as steel including stainless steel but such metallic pipes are relatively heavy. It is however highly desirable in many industries such as the oil and gas / energy industry to be able to provide as lightweight pipes as possible so that such pipes can be stored, transported & lifted etc. as easily as possible. Other materials such as composite and thermoplastic composite materials are therefore being considered to be used in the manufacture of the main length of such pipes but it is likely that the end fittings of such lengths will still to be manufactured from metal due to many considerations (in particular the strength thereof). It is therefore considered important to be able to make such metallic end fittings as lightweight but also as strong as possible (otherwise the heavy and fittings would defeat the purpose of providing lightweight main lengths of such an overall pipe) although there are many engineering aspects that need to be taken into account when designing such metallic end fittings (including minimising the risk of the end fitting being blown off the end of the composite main length of the pipe) and therefore many problems to be solved and also engineering compromises to be considered. Two assembly methods widely used to apply metal fittings to pipes are crimping and swaging. Both crimping and swaging rely on application of radial force to a metal ferrule that is positioned over the pipe end, such that the ferrule is plastically deformed. In doing so, radial contact pressure is produced at the interface between the ferrule and the pipe. The pipe reacts with an equal and opposite force, referred to as the normal force, which restrains the ferrule to the pipe in the axial direction. The maximum load that can be applied axially before the ferrule releases is simply a function of the normal force multiplied by the coefficient of friction between the ferrule and the pipe. Swaging and crimping differ only in the direction that the assembly force is applied. During the swaging process, the ferrule and pipe are pushed or drawn together through a static reducing die with a tapered internal profile, thereby reducing the outside diameter of the ferrule. Crimping achieves the same outcome by instead applying a direct radial load to a series of collets assembled around the outer diameter of the ferrule. The collets radially compress until the desired internal diameter is reached, at which point the collets contact each other and prevent further compression of the ferrule. Both methods are appropriate for applying metal fittings to metal pipes but are less suited for use with composite pipes designed for high internal pressures in applications such as the oilfield or production, transportation and storage of pressurised gasses such as Hydrogen. The present invention seeks in certain embodiments to provide a metal end fitting assembly for composite pipes that seeks to meet such requirements. SUMMARY In accordance with a first aspect of the invention there is provided an end fitting assembly for a pipe having an inner throughbore, the end fitting assembly comprising: a spigot portion and a ferrule portion; the spigot portion provided generally at the end of the pipe and which comprises a seal member arranged to seal the inner throughbore of the pipe at or toward the end of the pipe and in use the spigot portion is arranged to transfer axial force acting upon it to the ferrule portion; wherein the ferrule portion comprises an axial length and has an inner throughbore and which is configured for fitment around an outer end region of the pipe; and wherein the end fitting assembly is arranged such that in use, pressure of fluid within the inner throughbore of the pipe acts on the inner throughbore of the pipe to create a greater frictional force between the outer surface of the pipe and the inner surface of the ferrule portion when compared with the axial force acting on the end fitting assembly such that the end fitting assembly is retained upon the pipe. Preferably the pipe is formed from a composite material such that the pipe is a composite pipe. Typically, the pipe is a generally cylindrically shaped pipe having a longitudinal length with an inner throughbore, and outer surface and having a sidewall thickness therebetween (that is, the sidewall thickness is the material of the pipe that is between the outer surface and the inner throughbore thereof). Typically, the pipe comprises an outer end region around which the ferrule portion is fitted. Preferably, at least some of the ferrule portion is co-axially arranged with the seal member of the spigot portion. More preferably, at least some of the axial extent of the ferrule portion is co-axially arranged with the seal member of the spigot portion. Preferably the inner throughbore of the ferrule portion is configured for press fitment around an outer end region of the composite pipe and in use is arranged to surround (such as in a sleeve arrangement) at least an axial length or section of the pipe. A certain amount (which varies dependent upon a wide number of factors including materials used, diameters of the components (including sidewall thickness etc.) of press fitment provides the advantage that the end fitting assembly won’t fall off if for example the pipe is placed vertically even when there is no pressurised fluid within the inner throughbore of the pipe – and it also enables the end assembly to have an initial bite with the outer end region of the composite pipe (or sufficient frictional engagement between the inner throughbore of the ferrule portion and the outer end region of the composite pipe) which enables the end fitting assembly to build up the sufficient frictional force required between the inner throughbore of the ferrule and the outer surface of the pipe – without that, the inventor has realised that the interface between the two isn’t sufficiently energised when pressure in the composite pipe starts building up which means the pipe end assembly can be pushed off the end of the composite pipe and thus the connection therebetween can fail (i.e. without said sufficient frictional engagement, the inner throughbore of the ferrule portion could slide or be pushed or otherwise be forced off the outer end region of the composite pipe because the axial force acting on the end fitting assembly is greater than the force created by said frictional engagement between the inner throughbore of the ferrule portion and the outer end region of the composite pipe). Typically, embodiments of the present invention have the advantage that the efficacy of the end fitting assembly retention is dependent on and / or provided by the composite pipe modulus and thickness relative to the ferrule modulus and thickness / geometry. Also, embodiments of the present invention typically have the advantage that the efficacy of the end fitting assembly retention is increased by virtue of initial interference preferably being provided between the elastically deformable annular portion during / after its insertion into the end of the composite pipe. In one or more preferred embodiment(s), the spigot portion and the ferrule portion are conjoined together at manufacture such that they form a single unitary component being an end fitting assembly for a pipe. In one or more preferred embodiment(s), the spigot portion and the ferrule portion are separate portions from one another and in such more preferred embodiments, the end fitting assembly further comprises a locking arrangement adapted to selectively lock the spigot portion and the ferrule portion together. In such one or more preferred embodiment(s), the locking arrangement preferably comprises one or more locking surfaces provided on at least one of and preferably both of the spigot portion and the ferrule portion. Typically, said one or more locking surfaces maybe one or more co-operating surfaces such as one or more co-operating threaded surfaces provided on each of the spigot portion and the ferrule portion which are coupled together by relative rotation in a first direction of the said co-operating threads during making up of the end fitting assembly. Preferably, said co-operating threads prevent unintended axial separation of the spigot portion and the ferrule portion such that the spigot portion and the ferrule portion can be intentionally separated from one another by causing rotation of the said co- operating threads relative to one another in a second (opposite to the first) direction. In other more preferred embodiments, said one or more locking surfaces maybe one or more co-operating abutment surfaces provided on each of the spigot portion and the ferrule portion which are placed in abutment against each other and preferably are at least one of and more preferably both of coupled together or placed in abutment together typically by relative rotation of the said co-operating threads during making up of the end fitting assembly. Typically, the spigot portion comprises a body portion, and may further comprise an elastically deformable annular portion configured for insertion into an end of the pipe, and may further comprise a flange portion, wherein the flange portion may be provided intermediate the body portion and the elastically deformable portion, and wherein the flange portion may comprise a proximal end configured for abutment against a terminal edge of the pipe, and may further comprise a distal end directed away from the terminal edge of the pipe. Typically, the distal end of the flange portion of the spigot portion is adapted to abut the locking ring member and wherein the locking ring member may be configured for screw-threaded engagement with the ferrule portion and may further be arranged for frictional engagement against the flange portion of the spigot portion. The ferrule portion may further surround a flange portion of the spigot portion. In other more preferred embodiments, the end fitting assembly for a pipe may further comprise a locking ring member wherein said locking ring member is a separate component to that of at least one of the spigot portion and the ferrule portion. The locking ring member preferably comprises one or more locking surfaces provided thereon. Alternatively, or additionally, the locking ring member may comprise one or more abutment surfaces provided thereon and which are arranged to be placed in abutment against one or more respective abutment surfaces provided on at least one of and optionally each of the spigot portion and the ferrule portion during making up of the end fitting assembly such that said one or more respective abutment surfaces remain in abutment with each other whilst the end fitting assembly is connected to the end of the pipe. Optionally, the flange portion of the spigot portion is arranged to transfer load to the ferrule portion via the locking ring. Optionally, the spigot and the ferrule are mechanically interlocked by the locking ring. Optionally, the elastically deformable annular portion of the spigot comprises a thin- walled portion. Optionally, the thin-walled portion is configured for elastic radial deflection against the composite pipe bore as the pipe bore expands and contracts in use. Optionally, in certain preferred embodiments of the present invention the elastically deformable annular portion of the spigot is provided with a circumferential raised formation around its distal end and more preferably, the said circumferential raised formation is adapted and / or arranged in use to seal against a surface and more preferably an inner throughbore of the pipe in order to provide a seal between the inner throughbore of the pipe and the outer throughbore of the end fitting assembly. Conveniently, the said certain preferred embodiments of the present invention of end fitting assembly obviate the need for elastomer O-ring seals. Certain less preferred embodiments of the end fitting assembly may comprise one or more O-ring seals such as elastomer O-ring seals instead of said circumferential raised formation. Optionally, the circumferential raised formation is located at, or proximate, the terminal end of the thin-walled portion. Optionally, the circumferential raised formation is a nib. Optionally, the nib of the thin-walled portion has an outer diameter configured for interference fitment with the inner diameter of the composite pipe, wherein the nib is configured to create a localised high contact pressure between the spigot and the composite pipe that is greater than the internal hydrostatic force within the composite pipe in use. Optionally, the spigot comprises a radiused portion intermediate its elastically deformable thin-walled portion and the flange portion. Advantageously, the radiused portion intermediate the thin-walled portion and the flange portion is configured to provide a smooth transition of spigot wall thickness from the thin-walled portion to the spigot flange portion. Accordingly, the risk of hoop failure of the thin-walled section under high internal pressures in use is mitigated. Optionally, the ferrule is formed comprising an inside diameter or bore that is smaller than the diameter of the composite pipe to which it is to be fitted. Optionally, the ferrule portion comprises an outer diameter that is tapered from a location near its proximal end towards its distal end. Optionally, the taper has a taper angle of in the region of between 0.1o and 15o and more preferably in the region of between 0.5o and 1.5o and most preferably in the region of 1o. Advantageously, the tapered profile of the ferrule outer diameter enables a progressive increase of circumferential stiffness along the length of the ferrule-pipe interface region. Optionally, the inner surface of ferrule is provided with an undercut region extending inwardly from its terminal end. Optionally, the undercut region extends in the region of between 0.1 inches and 5 inches and more preferably in the region of between 0.5 inches and 2.5 inches and most preferably in the region of approximately 1.25 inches from the terminal end of the ferrule, optionally at an angle of in the region of between 0.1o and 15o and more preferably in the region of between 0.5o and 1.5o and most preferably in the region of 1o. Optionally, at its proximal end, the ferrule comprises an internally threaded portion configured for screw-threaded engagement with complementary threads provided on the locking ring. Optionally, the locking ring is locatable intermediate the spigot body and the ferrule. Optionally, the locking ring comprises a plurality of formations configured for engagement with a suitable tool for screwing and unscrewing said locking ring into and from the ferrule, respectively. It will be appreciated that features described in relation to one aspect may be equally combined with any other aspect described herein. BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: Embodiments of the present invention will now be described, by way of example only and with reference to the accompanying drawings, in which:- Figure 1 shows an isometric sectional view of a first embodiment of a pipe end fitting assembly in accordance with the invention; Figure 2 shows a side sectional view of the end fitting assembly of Figure 1; Figure 3a shows a side sectional view of a spigot portion of the end fitting assembly of Figures 1 and 2; Figures 3b and 3c show details of the spigot portion of Figure 3a; Figure 4a is a side sectional view of a ferrule portion of the end fitting assembly of Figures 1 and 2; Figures 4b and 4c show details of the ferrule portion of Figure 4a; Figure 5a is a side sectional view of an end region of a composite pipe adapted for use with an end fitting assembly in accordance with the invention, such as the end fitting assembly of Figure 1; Figure 5b is an end view of the end region of the composite pipe of Figure 5a; Figure 5c is a detailed view of the terminal edge of the end region of the composite pipe of figure 5a; Figure 6(a) shows a cross-sectional view of a second embodiment of a pipe end fitting assembly in accordance with the invention being shown in use mounted on the end of a pipe, the cross section being Section A-A through the end view of the pipe end fitting assembly as shown in Figure 6(b), and the second embodiment of pipe end fitting assembly comprising three main and separate / separable components of a ferrule portion, a locking ring and a spigot portion; Figure 6(b) shows an end view of the second embodiment of the pipe end fitting assembly of Figure 6(a); Figure 7(a) shows a cross-sectional view of a third embodiment of a pipe end fitting assembly in accordance with the invention being shown in use mounted on the end of a pipe, the cross section being Section A-A through the end view of the pipe end fitting assembly as shown in Figure 7(b), and the third embodiment of pipe end fitting assembly comprising two main components of a ferrule portion integrally combined with a locking ring portion and a separate spigot portion; Figure 7(b) shows an end view of the third embodiment of the pipe end fitting assembly of Figure 7(a); Figure 7 (c) is a cross sectional view of the ferrule portion integrally combined with a locking ring portion of the end fitting assembly of Figures 7(a) and 7(b), the cross section being Section B-B through the end view of the ferrule portion integrally combined with a locking ring portion as shown in Figure 7(d); Figure 7(d) shows an end view of the ferrule portion integrally combined with a locking ring portion of Figure 7(c); Figure 7 (e) is a cross sectional view of the spigot portion of the end fitting assembly of Figures 7(a) and 7(b), the cross section being Section C-C through the end view of the spigot portion as shown in Figure 7(f); Figure 7(f) shows an end view of the spigot portion of the end fitting assembly of Figures 7(a) and 7(b); Figure 8(a) shows a cross-sectional view of a fourth embodiment of a pipe end fitting assembly in accordance with the invention being shown in use mounted on the end of a pipe, the cross section being Section A-A through the end view of the pipe end fitting assembly as shown in Figure 8(b), and the fourth embodiment of pipe end fitting assembly comprising two main components of a ferrule portion and a separate spigot portion integrally combined with a locking ring portion; Figure 8(b) shows an end view of the fourth embodiment of the pipe end fitting assembly of Figure 8(a); Figure 8(c) is a cross sectional view of the separate ferrule portion of the end fitting assembly of Figures 8(a) and 8(b), the cross section being Section B-B through the end view of the ferrule portion as shown in Figure 8(d); Figure 8(d) shows an end view of the separate ferrule portion of Figure 8(c); Figure 8(e) is a cross sectional view of the separate spigot portion integrally combined with a locking ring portion of the end fitting assembly of Figures 8(a) and 8(b), the cross section being Section C-C through the end view of the spigot portion integrally combined with a locking ring portion as shown in Figure 8(f); Figure 8(f) shows an end view of the separate spigot portion integrally combined with a locking ring portion of the end fitting assembly of Figures 8(a) and 8(b); Figure 9(a) shows a cross-sectional view of a fifth embodiment of a pipe end fitting assembly in accordance with the invention being shown in use mounted on the end of a pipe, the cross section being Section A-A through the end view of the pipe end fitting assembly as shown in Figure 9(b), and the fifth embodiment of pipe end fitting assembly comprising one single integral component of a ferrule portion combined with a spigot portion; Figure 9(b) shows an end view of the fifth embodiment of the pipe end fitting assembly of Figure 9(a); Figure 9(c) shows a cross-sectional view of the fifth embodiment of the pipe end fitting assembly as shown in Figure 9(a) but shown in Figure 9(c) not being mounted on the end of the pipe, the cross section being Section B-B through the end view of the pipe end fitting assembly as shown in Figure 9(d); and Figure 9(d) shows an end view of the fifth embodiment of the pipe end fitting assembly of Figure 9(c). DETAILED DESCRIPTION OF THE DRAWINGS FIRST EMBODIMENT OF END FITTING ASSEMBLY 1 Referring now to the drawings, a first example or embodiment of an end fitting assembly 1 in accordance with the present invention is shown in Figures 1 and 2 and comprises a spigot portion 2 or spigot 2, a ferrule portion 3 or ferrule 3 and a locking ring 4, where the end fitting assembly 1 is for use with a composite pipe 10 as also shown in Figures 1 and 2 and also as shown solus in Figure 5a. Preferably, the ferrule 3 is attached to the pipe 10 by press-fitment though axial loading. The composite pipe 10 may be a carbon fibre wound composite pipe 10. SPIGOT PORTION OF THE FIRST EMBODIMENT With reference to Figure 3a, spigot portion 2 comprises a body portion 21, an annular flange portion 22, and an annular spigot end 23. Spigot portion 2 is preferably of single-piece construction. Preferably, the spigot portion 2 is formed from aluminium. Spigot end 23 is an elastically deformable annular portion configured for insertion within the bore of a pipe 10. Flange portion 22 has a proximal end configured for abutment against the terminal edge 13 of the pipe 10. Flange portion 22 has a distal end (in the form of shoulder 224) adapted to abut a load bearing face of a locking ring 4 which frictionally engages said flange portion 22 in use. Flange portion 22 extends around a proximal end of the body portion 21. Flange portion 22 has an outer surface 221 and an inner surface 222. The diameter of the outer surface 221 is greater than the outer diameter of the body portion 21 such that the flange 22 defines a collar 223 that surrounds the proximal end of the body portion21. At its distal end, collar 223 comprises the shoulder 224 which is adapted to abutthe locking ring 4 that is locatable intermediate the spigot portion 2 and a ferrule 3 as shown by way of example in Figures 1 and 2. Provision of the shoulder 224 in conjunction with the locking ring 4 provides a means for transferring load from the spigot 2 to the ferrule 3. By means of locking ring 4, the spigot 2 and ferrule 3 are mechanically interlocked. The diameter of the flange portion’s inner surface 222 is less than the outer diameter of the body portion 21 such that a substantially circular recess or shoulder 227 is formed in the base of the body portion 21. In this manner, flange portion 22 has the appearance of both surrounding, and depending from the proximal end of the body portion 21. At its lower end, flange 22 has a base 225 having a profile configured to abut the terminal edge 13 of a composite pipe 10, which is formed or machined with a complementary profiled mating surface (Figures 1, 2, 5a, 5c). The profile may include a radiused portion R1, such that the base 225 is shaped in the form of a quarter-pipe as best shown Figure 3a. In examples, R1 has a radius of approximately 0.50 inch. Spigot end 23 projects from the base 225 of flange 22. The spigot end 23 comprises a wall having an outer surface 231 and an inner surface 232. The wall is a thin-wall (and in particular comprises a thinner side wall compared to the rest of the spigot portion 2 and is therefore also referred to as thin wall). In examples, the thin wall has a thickness of approximately 0.11 inches. The diameter of the spigot end 23 inner surface 232 is substantially the same as the diameter of the flange inner surface 222 such that the spigot end inner surface 232 and the flange inner surface 222 are substantially coplanar. As shown in Figure 3b, proximate, or at, the terminal end (left hand most end as shown in Figure 3a) of the annular spigot end 23 there is provided a raised formation 233 which encircles said spigot end 23. The raised formation 233 may be an upstanding annular nib, ridge or other suitable formation. The raised formation 233 has an outside diameter which is arranged for an interference fit with the inside diameter or bore of the pipe 10. The outside diameter of the raised formation 233 is specifically sized to create a localised area of high contact pressure between the raised formation 233 and the pipe 10, which is configured to exceed the internal hydrostatic pressure applied to the pipe 10 in use, such that a seal is formed therebetween. The thin-walled annular spigot end 23 behind the raised formation 233 is configured to deflect radially into the pipe bore 10. The raised formation 233 is thus allowed to ‘follow’ the pipe bore 10 during pipe 10 expansion. The raised formation 233 thereby provides a seal with the inner throughbore of the composite pipe 10 but in an alternative (less preferred) embodiment (not shown) the raised formation 233 is replaced by an elastomeric seal (not shown) such as an “O”-Ring (not shown) provided within a recess or groove (not shown) formed around the outer end of the annular spigot end 23 where the “O”-Ring provides the seal with the inner throughbore of the composite pipe 10. However, such an alternative “O”-Ring embodiment is less preferred because that arrangement will necessitate a greater sidewall thickness being needed for the annular spigot end 23 which therefore has a knock on effect of reducing the available inner diameter of the throughbore of the annular spigot end 23 which then in turn has the undesirable effect of the end fitting assembly 1 having to be increased in size in order to compensate in order for the end fitting assembly 1 to be strong enough to withstand the forces involved and that then makes the end fitting assembly 1 heavier which is of course against one of the most important aims for embodiments of the present invention. The junction of the spigot end 23 outer surface 231 and the base 225 of the flange portion 22 is filleted, the fillet having a radius R1. The fillet provides a smooth transition of material wall thickness from the pipe 10 to the spigot flange portion 22. This helps mitigate hoop failure of the thin-walled spigot end 23 under high internal pressure in use. The use of aluminium for spigot construction aids this due to the large amount of plastic strain afforded (>8% minimum elongation). Furthermore, aluminium has a low modulus in comparison to steel, but exhibits a high specific strength, thus reducing the overall weight of the complete end fitting assembly 1 in comparison to one of steel construction. Spigot end 23 provides a pressure-tight seal with a pipe 10, the seal being absent sealing rings, such as but not limited to, elastomeric O-rings. The spigot end 23 also serves to transfer loads to the ferrule 3, via the locking ring 4. The spigot portion 2 is shown in figures 1 and 2 as having a substantially closed end except for an autoclave fitting port 35 (which typically has internally formed threads 36 provided on its inner surface) and which is in fluid communication with an autoclave fluid pressure channel 37 formed along the longitudinal central axis of the spigot portion 2 and which in turn is in fluid communication with the inner throughbore of the pipe 10. An autoclave test probe (not shown) can be screwed into the autoclave fitting port 35 in order to monitor the internal fluid pressure particularly as it is increased during testing of the end fitting assembly 1. However, it should be noted that it is likely that the majority of manufactured embodiments of end fitting assembly in accordance with the present invention will be used to connect one end of a first pipe 10 to a second but oppositely directed end fitting assembly (not shown) mounted on an end of a second pipe 10 and such embodiments of will have a maximum diameter throughbore (which typically will be the same diameter as that of the rest of the spigot portion 2) such that the end fitting assembly 1 has a full bore to allow for maximum flow of fluids therethrough in use of a series of so connected pipes 10. Alternatively, if an end fitting assembly 1 is intended to terminate a pipe 10 then the outer end of the spigot portion 4 can be modified to be solid / sealed (i.e. with no throughbore therethrough or if there is a throughbore, it is plugged / sealed). FERRULE PORTION OF THE FIRST EMBODIMENT With reference to Figures 1 and 2, ferrule portion or ferrule 3 is configured for location over the end portion of a composite pipe 10 and the flange 22 or collar 223 portion of the spigot portion or spigot 2. Ferrule 3 is fitted over the composite pipe 10 by press-fitment. For example, in a test of one example of the first embodiment of an end fitting assembly 1 in accordance with the present invention, 65 to 85 tonnes of press fitting was required to be subjected upon the ferrule 3 to press-fit the ferrule 3 on to the end of the composite pipe 10 and spigot 2 (the spigot 2 had already been inserted into the throughbore of the composite pipe 2). The pressure within the throughbore of the composite pipe 10 was then increased as part of the test up to approx.22,500 psi, and the targeted end load of 142 tonnes was successfully attained in that the end fitting assembly 1 was retained on the end of the composite pipe 10 (the targeted end load of 142 tonnes is the equivalent to attempting to pull the end fitting assembly 1 off the end of the composite pipe 10 with 142 tonnes of load). The successful attainment of the end fitting assembly 1 (i.e. it being retained on the end of the composite pipe 10) is at least partly achieved by arranging the respective diameters to set up for a certain amount of press-fitting (or interference or friction fitting) being required – in one simulated test for example, having a 0.010” of interface (i.e. the outer diameter of the composite pipe is 0.010” greater than the inner diameter (ØBORE) of the ferrule 3) wasn’t sufficient to provide the frictional force to retain the end fitting assembly 1 on the end of the composite pipe 10 when the pressure was increased and the end fitting assembly 1 failed at 14,500psi (failure meaning that the end fitting assembly 1 was forced off the end of the composite pipe 10. Alternatively, arranging there to be a 0.017” of interface (i.e. the outer diameter of the composite pipe 10 is 0.017” greater than the inner diameter of the ferrule 3) provided the very surprising result that it was sufficient to provide the frictional force to retain the end fitting assembly 1 on the end of the composite pipe 10 when the pressure was increased up to 22,500 psi during a simulation test. Optionally, the ferrule 3 is formed from steel. The ferrule 3 is arranged such that its internal bore (ØBORE) is dimensioned to be slightly greater than the outer diameter of the outer surface 221 of the flange portion 22 such that there is a clearance fit therebetween. In order to resist the axial load and contact pressure at the interface between the ferrule 3 and a composite pipe 10, the ferrule 3 is particularly shaped and thickened. To induce an inherent resistance to axial loads while the internal pressure of the pipe 10 is equal to ambient pressure, ferrule 3 comprises an inside diameter or bore (ØBORE) that is slightly smaller than the outside diameter of the pipe 10 in the area of mutual engagement therebetween such that the ferrule 3 has an interference fit (also known as a press or friction fit) with said pipe 10. This is particularly useful when the pipe 10 is a lubricator pipe such as that used in oil field operations (or a pipe 10 used in any other suitable operation such as the oilfield or production, transportation and storage of pressurised gasses such as hydrogen), whereby large static loads may be encountered during rig-up, for example, when a string of several lubricators may be lifted simultaneously, with the weight of the string acting on each connection. In this configuration, the ferrule 3 is located onto the pipe 10 with an axial load applied to push the ferrule 3 over the end portion of the pipe 10, the outer diameter of which is reduced as a result. As shown in Figures 2, 4a and 4b, the outer diameter of the ferrule 3 is tapered inwardly from a location near its proximal end 31 towards its distal end 32. In this way, the wall thickness of the ferrule 3 reduces towards its distal end 32. Optionally, as shown in Figure 4b, the said taper angle of the outer diameter of the ferrule 3 is 1o. The tapered profile of the ferrule 3 outer diameter allows a progressive increase (from the distal end 32 to the proximal end 31) of circumferential stiffness along the length of the ferrule-pipe interface region. The taper has the effect of minimising the sectional stiffness gradient of the entire pipe 10 and end fitting assembly 1 region so that at least some continuity of deflections and stresses are maintained along the length of the end fitting assembly 1. As shown in Figure 4a and in particular in figure 4b, at its distal end 32, the inner surface of ferrule 3 is provided with an undercut region 33 which extends inwardly from the terminal end (the left hand end shown in Figures 4a and 4b) of the ferrule 3. In examples, the undercut region 33 may extend to a length in the region of 1.25 inches from the terminal end of the ferrule 3, and said inner surface of the undercut region 33 has an outwardly tapering angle of 1o(in that the said inner surface tapers outwardly such that the inner diameter of the said inner surface is greater at the said distal end than it is 1.25 inches away from the distal end at which point it has the radius Rx). In a first instance, this ensures proper centralisation of a composite pipe 10 outer diameter during the initial stages of assembly. In a second instance, this mitigates the tendency for the composite pipe 10 to “balloon” at the ferrule transition (due to the large difference in sectional stiffness between a composite pipe 10 and the steel ferrule 3) by enabling differential radial expansion of the pipe 10 without introducing points of high contact stress. Where the undercut region 33 transitions to the regular inner surface of the ferrule bore 3, there is provided a radius Rx. In examples, the radius is 8 inches. The radius minimises peak contact stress at the point of diametric interference between a pipe 10 and the ferrule 3 during assembly and also in use. At its proximal end 31, ferrule 3 has an internally threaded portion 34 configured for screw-threaded engagement with complementary threads 6 provided on locking ring 4 that is locatable intermediate the spigot body 2 and the ferrule 3 as shown by way of example in Figures 1 and 2. By means of locking ring 4, spigot 2 and ferrule 3 are mechanically interlocked. As shown Figures 1 and 2, locking ring 4 comprises a plurality of formations 41 configured to permit engagement with a suitable tool for screwing and unscrewing said locking ring 4 into and from the ferrule 3, respectively. LOCKING RING PORTION OF THE FIRST EMBODIMENT The locking ring 4 of the first embodiment of the end fitting assembly 1 is a separate component from the spigot portion 2 and the ferrule portion 3, where the locking ring 4 is in the form of an annular ring having a load bearing face 5 (on its inwardly directed end) arranged to bear load against the shoulder 224 of the spigot portion 2 in use of the end fitting assembly 1. As shown in Figures 1 and 2, locking ring 4 comprises a plurality of formations 41 configured to permit engagement with a suitable tool for screwing and unscrewing said locking ring 4 into and from the ferrule 3, respectively. The locking ring 4 has an externally threaded portion 6 configured for screw-threaded engagement with complementary threads 34 provided on the ferrule 3, such that once the spigot portion 2 is slid into the outer end of the ferrule portion 3, the threaded portion 6 of the locking ring 4 can be screwed into the threads 34 of the ferrule portion 3 until the load bearing face 5 bears against the shoulder 224 and the end fitting assembly 1 of the first embodiment is thus assembled. The end fitting assembly 1 can be mounted upon an end of a composite pipe 10 in any suitable sequence but typically is mounted upon an end of a composite pipe 10 in the following sequence:- 1. the spigot portion 2 is fully inserted into the throughbore of the end of the pipe 10 until it reaches the position and / or configuration shown in Figures 1 and 2; 2. the ferrule portion 3 is fully slid and forced over the outer end of the pipe 10 until it reaches the position and / or configuration shown in Figures 1 and 2; and 3. the locking ring 4 is slid over the outer end of the spigot portion 2 and is screwed into the annular outer gap between the ferrule portion 3 and the spigot portion 2 until it is tightened into the position and / or configuration shown in Figures 1 and 2. COMPOSITE PIPE In order to ensure that the ferrule 3 and spigot 2 of the end fitting assembly 1 interacts with a composite pipe 10 in the intended manner, some modification of the pipe 10 may be required. For example, when supplied from the manufacturer, a composite pipe 10 might have insufficiently round inner and / or outer diameters, for example it may be slightly oval at its ends. Accordingly, to ensure correct interaction with the ferrule 3, the exterior of the pipe 10 should be machined to a substantially circular outside diameter (ØOuter) having a tightly controlled tolerance, the diameter configured to provide an interference fit with the bore of the ferrule (ØBORE) 3. To aid centralisation and smooth entry of the pipe 10 into the ferrule 3, a lead in 11 (Figure 5c) may be machined into the end of the pipe 10. Optionally, the lead in 11 may have an angle of approximately 10o. In examples, the lead in 11 may have a length of approximately 0.25 inches. To reduce peak contact stress, the termination of the lead in 11 may be machined with a radius 12. In examples, radius 12 may be approximately 0.25 inches. To enable a pressure-tight seal with the spigot 2, the bore of the pipe 10 should be machined to a substantially circular inside diameter (ØInner) (Figure 5a) having a tightly controlled tolerance, the diameter (ØInner) configured to provide an interference fit with the annular spigot end 23. Optionally, the outside diameter (ØOuter) and inside diameter (ØInner) should be concentric to within 0.002 inch. In an example, the inside diameter (ØInner) may be machined to be approximately 4.209 inches. In cases where the composite pipe 10 comprises a liner 10L such as that shown in Figures 1 and 5a, in order to avoid encroachment into the pipe’s 10 laminate structure 9, care must be taken so that machining is limited to preferably only part way through the innermost liner 10L (which is formed from a suitable material, typically polymeric or metallic material) of the composite pipe 10 so that the raised formation 233 is arranged to seal against the liner 10L. Alternatively, some composite pipes 10 don’t require a liner 10L (particularly where porosity of the laminate structure 9 isn’t a concern) and in that case, the inner bore of the laminate structure 9 is machined. Additionally, at its terminal edge 13, the bore of the composite pipe 10 should be provided with a profile configured to matingly engage the base 225 of the spigot annular flange portion 22. Accordingly, terminal edge 13 may include a radiused portion R2 that is complementary to the filleted or radiused portion R1 of the spigot annular flange portion 2. In examples, R2 has a radius of approximately 0.50 inch. The arrangement and functionality of the pipe end fitting assembly 1 of the present invention stems from the observation that interface contact pressure increased as a function of internal pressure P (Figure 2) applied to a composite pipe 10, resulting in an additional and proportional increase in axial retaining force. The high contact pressure at the ferrule - pipe interface was a direct result of the large difference in moduli between the composite pipe 10 and the ferrule 3; estimates of the composite pipe modulus were between 30 and 50 GPa in the hoop direction, under a quarter that of steel (200 GPa). The result of this is that, under increasing internal pressure, the composite pipe 10 will expand at a rate considerably greater than the steel ferrule 2. As the composite pipe’s 10 diameter is constrained by the ferrule 2, pressure builds at the contact interface between them. This observation prompted the question of whether it would be possible for interface contact pressure to provide the entirety of the normal force required to restrain the ferrule 2 to the composite pipe 10. If the normal / restraining force is constantly increasing with internal pressure, the connection would thus be "self-energising", with restraining force maintained at a magnitude consistently greater than the axial separation load. This bypasses any requirement for large swaging loads and reduces peak contact pressure at the interface, allowing the usage of, for example, the high strength low alloy steel mentioned above. A reduction in not only weight but also complexity is therefore possible by exploiting this phenomenon. For these reasons, embodiments of the end pipe assembly 1 in accordance with the present invention provide a distant improvement over known end pipe fittings. SECOND EMBODIMENT OF END FITTING ASSEMBLY 601 A second embodiment of an end fitting assembly 601 in accordance with the present invention is shown in Figures 6a and 6b. The second embodiment of an end fitting assembly 601 comprises many similar components to the first embodiment of end fitting assembly 1 shown in Figures 1 to 5c and, where that is the case, the similar components used for the second embodiment of end fitting assembly 601 in Figures 6a and 6b have the number 600 (for two digit reference numerals) or 6000 (for three digit reference numerals) as appropriate added to the reference numeral used for the first embodiment of end fitting assembly 1 shown in Figures 1 to 5c, and where such similar components have the same or similar characteristics, dimensions, performance and end results etc., such same or similar characteristics, dimensions, performance and end results etc. may not be described again for the sake of brevity but differences therebetween may in particular be hereinbelow discussed. Accordingly, the second embodiment of an end fitting assembly 601 comprises a spigot portion 602, a ferrule portion 603 and a locking ring 604, where the end fitting assembly 601 is for use with a composite pipe 610 as also shown in Figures 6a and 6b. The spigot portion 602, ferrule portion 603 and composite pipe 610 of the second embodiment of end fitting assembly 601 as shown in Figures 6a and 6b are very similar if not identical to the spigot portion 2, ferrule portion 3 and composite pipe 10 of the first embodiment of end fitting assembly 1 shown in Figures 1 to 5c, albeit the spigot portion 602 comprises a full bore throughbore. However, the locking ring 604 differs from locking ring 4 in that the locking ring 604 is generally an inverted T-shape and further comprises a locking ring flange 671 which has a certain width and which projects radially outwardly from the approximate midpoint of the locking ring 604, where the (spigot shoulder) load bearing face 605 (on its first inwardly (left facing as shown in Figure 6(a)) directed end) is arranged at the inwardly facing end of the locking ring 604 (left hand end as shown in Figure 6(a)) and is (like that of the first embodiment) arranged to bear load against the shoulder 6224 of the spigot portion 602 in use of the end fitting assembly 601. As also shown in Figure 6(a), the locking ring flange 671 also comprises a (ferrule end facing) first load bearing face 673 which lies on a plane perpendicular to the longitudinal axis of the end fitting assembly 601 (and which is therefore parallel to the load bearing face 605) and is arranged to face axially inwardly (left facing as shown in Figure 6(a)) and therefore face towards the end of the ferrule 603 and is further arranged to butt thereagainst when the locking ring 604 is slipped over the outward most end of spigot portion 602 (the right hand most end thereof in Figure 6(a)) and is first slid towards the ferrule 603 and flange portion 622 and is then rotated such that the threaded portion 606 of the locking ring 604 is screwed into the threads 634 of the ferrule portion 603 until :- i) the load bearing face 605 of the locking ring flange 671 bears against the shoulder 6224 of the spigot portion 602; and ii) the first load bearing face 673 butts against the end of the ferrule 603 and can be tightened until sufficient torque is input into the screw threaded connections and the faces 605, 6224 and 673 and end of the ferrule such that the end fitting assembly 601 of the second embodiment is thus assembled. As can be further seen in Figure 6(a), the locking ring 604 further comprises a second load bearing face 655 (on its outwardly (right facing as shown in Figure 6(a)) directed end) and which is arranged to bear load against a shoulder (not shown) of another component such as another suitably shaped spigot portion (not shown) of an adjacent but oppositely directed end fitting assembly (not shown) and composite pipe combination (not shown) to which the end fitting assembly 601 is to be connected. As also shown in Figure 6(a), the locking ring flange 671 also comprises a (ferrule end facing) second load bearing face 683 which lies on a plane perpendicular to the longitudinal axis of the end fitting assembly 601 (and which is therefore parallel to both the load bearing face 605 and the first load bearing face 673) and is arranged to face axially outwardly (right facing as shown in Figure 6(a)) and therefore face away from the end of the ferrule 603 and is further arranged to face towards an end of another ferrule (not shown) and butt thereagainst when an adjacent but oppositely directed end fitting assembly (not shown) and composite pipe combination (not shown) are screwed onto the right hand side of the locking ring 604. Accordingly, the second embodiment of the end fitting assembly 601 has several advantages over the first embodiment in that the end fitting assembly 601 can retain more torque (due to it having two load bearing faces (the first load bearing face 605 and the second load bearing face 683)) compared to just the one load bearing face 5 of the first embodiment of end fitting assembly 1) and can also allow the end fitting assembly 601 to be connected to other components. THIRD EMBODIMENT OF END FITTING ASSEMBLY 701 A third embodiment of an end fitting assembly 701 in accordance with the present invention is shown in Figures 7a and 7b. The third embodiment of an end fitting assembly 701 comprises many similar components to the second embodiment of end fitting assembly 601 shown in Figures 6(a) and 6(b) and, where that is the case, the similar components used for the third embodiment of end fitting assembly 701 in Figures 7a and 7b have the number 700 (for two digit reference numerals) instead of 600 or have 7000 (for three digit reference numerals) instead of 6000 as appropriate added to the reference numeral used, and where such similar components have the same or similar characteristics, dimensions, performance and end results etc., such same or similar characteristics, dimensions, performance and end results etc. may not be described again for the sake of brevity but differences therebetween may in particular be hereinbelow discussed. Accordingly, the third embodiment of an end fitting assembly 701 comprises a spigot portion 702. However, unlike the second embodiment of the end fitting assembly 601 (which had ferrule portion 603 and locking ring 604 as separate components), the end fitting assembly 701 comprises a one piece ferrule and locking ring component 750. The third embodiment of end fitting assembly 701 is again for use with a composite pipe 710 as also shown in Figures 7a and 7b. As can be seen in both figures 7(a) and 7(c), the majority of the one piece ferrule and locking ring component 750 (in particular the left hand side) is similar or identical to the ferrule portion 603 but as can also be seen, the outermost end (the right hand end) of the one piece ferrule and locking ring component 750 significantly differs from the ferrule portion 603, in that the outermost end (the right hand end) of the one piece ferrule and locking ring component 750 comprises a radially inwardly projecting shoulder 705 which is arranged (like that of the first and second embodiments) to bear load against the shoulder 7224 of the spigot portion 702 in use of the end fitting assembly 701. The end fitting assembly 701 is assembled by:- i) inserting the spigot portion 702 into the inner bore of the composite pipe 710; and ii) firstly sliding and then secondly forcing the one piece ferrule and locking ring component 750 over the outward most end of spigot portion 702 (the right hand most end thereof in Figure 7(a)) until the load bearing face 705 of the one piece ferrule and locking ring component 750 bears against the shoulder 7224 of the spigot portion 702. Accordingly, the third embodiment of an end fitting assembly 701 has the advantage that no screw threads are required to be provided between the one piece ferrule and locking ring component 750 and the spigot portion 702 and therefore no screwing or rotation is required during the assembly of the third embodiment of an end fitting assembly 701. On the other hand, that also means that the third embodiment of an end fitting assembly 701 cannot be easily disassembled should that ever be required. FOURTH EMBODIMENT OF END FITTING ASSEMBLY 801 A fourth embodiment of an end fitting assembly 801 in accordance with the present invention is shown in Figures 8a and 8b. The fourth embodiment of an end fitting assembly 801 comprises many similar components to the second embodiment of end fitting assembly 601 shown in Figures 6(a) and 6(b) and, where that is the case, the similar components used for the fourth embodiment of end fitting assembly 801 in Figures 8a and 8b have the number 800 (for two digit reference numerals) instead of 600 or have 8000 (for three digit reference numerals) instead of 6000 as appropriate added to the reference numeral used, and where such similar components have the same or similar characteristics, dimensions, performance and end results etc., such same or similar characteristics, dimensions, performance and end results etc. may not be described again for the sake of brevity but differences therebetween may in particular be hereinbelow discussed. Accordingly, the fourth embodiment of an end fitting assembly 801 comprises a ferrule portion 803 (which is similar or identical to the ferrule portion 603). However, unlike the second embodiment of the end fitting assembly 601 (which had spigot portion 602 and locking ring 604 as separate components), the end fitting assembly 801 comprises a one piece spigot and locking ring component 860. The fourth embodiment of end fitting assembly 801 is again for use with a composite pipe 810 as also shown in Figures 8a and 8b. As can be seen in both figures 8(a) and 8(e), the majority of the spigot and locking ring component 860 (in particular the left hand side) is similar or identical to the spigot portion 602 but as can also be seen, the middle of or outermost end (the middle or right hand end) of the one piece spigot and locking ring component 860 significantly differs from the spigot portion 602, in that the middle or outermost end (the right hand end) of the one piece spigot and locking ring component 860 comprises a radially outwardly projecting threaded surface 806 which is arranged (like that of the first and second embodiments) to provided for threaded engagement with the inwardly projecting threaded surface 834 of the ferrule portion 803 in use of the end fitting assembly 801. The end fitting assembly 801 is assembled by:- i) inserting the one piece spigot and locking ring component 860 into the inner bore of the composite pipe 810; and ii) firstly sliding and then secondly forcing the ferrule portion 850 over the outward most end of the one piece spigot and locking ring component 860 (the right hand most end thereof in Figure 8(a)) until the inwardly projecting threaded surface 834 of the ferrule portion 803 meets the radially outwardly projecting threaded surface 806 of the one piece spigot and locking ring component 860 at which point the ferrule portion 850 is rotated onto and over the outward most end of the one piece spigot and locking ring component 860 such that it is also forced over the outer surface of the composite pipe 810. Accordingly, the fourth embodiment of an end fitting assembly 801 has the advantage that it has fewer components to assemble compared to the first 1 and second 601 embodiments of the end fitting assembly. FIFTH EMBODIMENT OF END FITTING ASSEMBLY 901 A fifth embodiment of an end fitting assembly 901 in accordance with the present invention is shown in Figures 9a and 9b. The fifth embodiment of an end fitting assembly 901 comprises many similar components to the second embodiment of end fitting assembly 601 shown in Figures 6(a) and 6(b) and, where that is the case, the similar components used for the fifth embodiment of end fitting assembly 901 in Figures 9a and 9b have the number 900 (for two digit reference numerals) instead of 600 or have 9000 (for three digit reference numerals) instead of 6000 as appropriate added to the reference numeral used, and where such similar components have the same or similar characteristics, dimensions, performance and end results etc., such same or similar characteristics, dimensions, performance and end results etc. may not be described again for the sake of brevity but differences therebetween may in particular be hereinbelow discussed. However, unlike the second embodiment of the end fitting assembly 601 (which had spigot portion 602, ferrule portion 603 and locking ring 604 as separate components), the end fitting assembly 901 comprises a one piece spigot, ferrule and locking ring component 970. The fifth embodiment of end fitting assembly 901 is again for use with a composite pipe 910 as also shown in Figures 9a and 9b. The end fitting assembly 901 is assembled on the end of the composite pipe 910 by :- i) sliding the undercut region 933 (which extends inwardly from the terminal end (the left hand end as viewed in Figure 9a) of the one piece spigot, ferrule and locking ring component 970 over the outer end of the composite pipe 910; ii) then forcing the one piece spigot, ferrule and locking ring component 970 further over and onto the outer end of the composite pipe 910 until the raised formation 9233 which encircles the internal spigot end 923 contacts the inner bore of the composite pipe 910; iii) then continued forcing the one piece spigot, ferrule and locking ring component 970 further over and onto the outer end of the composite pipe 910 and also forcing the raised formation 9233 along the inner bore of the composite pipe 910 until the profiled base 9225 abuts the terminal edge 913 of the composite pipe 910. Accordingly, the fifth embodiment of an end fitting assembly 901 has the advantage that no screw threads are required to be provided at all because it is formed of only one, integral component, that being the one piece spigot, ferrule and locking ring component 970 and therefore no screwing or rotation is required during the assembly of the third embodiment of an end fitting assembly 901 – it is simply forced over and under outer surface and inner bore respectively of the composite pipe 910. On the other hand, that also means that the fifth embodiment of the end fitting assembly 901 cannot be easily disassembled should that ever be required. All embodiments 1, 601, 701, 801 and 901 of the end fitting assembly hereinbefore described have the common advantage that they are able to be successful retained on the end of the composite pipe because their respective diameters are set up for a certain amount of press-fitting (or interference or friction fitting) being provided and which in turn provides the frictional force to retain the end fitting assembly 1, 601, 701, 801 and 901 on the end of the composite pipe when the pressure is increased to a relatively high operational pressure. Modifications and improvements may be made to the embodiments and examples described herein without departing from the scope of the invention.

Claims

CLAIMS:

1. An end fitting assembly for a pipe having an inner throughbore, the end fitting assembly comprising :- a spigot portion and a ferrule portion; the spigot portion provided generally at the end of the pipe and which comprises a seal member arranged to seal the inner throughbore of the pipe at or toward the end of the pipe and in use the spigot portion is arranged to transfer axial force acting upon it to the ferrule portion; wherein the ferrule portion comprises an axial length and has an inner throughbore and which is configured for fitment around an outer end region of the pipe; and wherein the end fitting assembly is arranged such that in use, pressure of fluid within the inner throughbore of the pipe acts on the inner throughbore of the pipe to create a greater frictional force between the outer surface of the pipe and the inner surface of the ferrule portion when compared with the axial force acting on the end fitting assembly such that the end fitting assembly is retained upon the pipe.

2. The end fitting assembly according to claim 1, wherein the inner throughbore of the ferrule portion is configured for press fitment around an outer end region of the pipe.

3. The end fitting assembly according to any preceding claim, wherein the spigot portion and the ferrule portion are conjoined together at manufacture such that they form a single unitary component.

4. The end fitting assembly according to any preceding claim, wherein the spigot portion and the ferrule portion are separate portions from one another and the end fitting assembly further comprises a locking arrangement adapted to selectively lock the spigot portion and the ferrule portion together.

5. The end fitting assembly according to claim 4, wherein the locking arrangement comprises one or more locking surfaces provided on at least one of the spigot portion and the ferrule portion.

6. The end fitting assembly according to claim 5, wherein the one or more locking surfaces comprise one or more co-operating threaded surfaces provided on each of the spigot portion and the ferrule portion which are coupled together by relative rotation in a first direction of the said co-operating threads during making up of the end fitting assembly.

7. The end fitting assembly according to either of claims 5 or 6, wherein the one or more locking surfaces comprise one or more co-operating abutment surfaces provided on each of the spigot portion and the ferrule portion which are placed in abutment against each other during making up of the end fitting assembly.

8. The end fitting assembly according to any of claims 1 or 2 or to any of claims 4 to 7 when not dependent upon claim 3, further comprising a locking ring member wherein said locking ring member is a separate component to that of at least one of the spigot portion and the ferrule portion.

9. The end fitting assembly according to claim 8, wherein the locking ring member comprises one or more locking surfaces provided thereon.

10. The end fitting assembly according to either claim 8 or 9, wherein the locking ring member comprises one or more abutment surfaces provided thereon and which are arranged to be placed in abutment against one or more respective abutment surfaces provided on at least one of the spigot portion and the ferrule portion during making up of the end fitting assembly such that said one or more respective abutment surfaces remain in abutment with each other whilst the end fitting assembly is connected to the end of the pipe.

11. The end fitting assembly according to any preceding claim, wherein the spigot portion comprises a body portion, an elastically deformable annular portion configured for insertion into an end of the pipe, and a flange portion, wherein the flange portion is provided intermediate the body portion and the elastically deformable portion, and wherein the flange portion comprises a proximal end configured for abutment against a terminal edge of the pipe, and a distal end directed away from the terminal edge of the pipe.

12. The end fitting assembly according to claim 11 when dependent upon any of claims 8 to 10, wherein the distal end of the flange portion of the spigot portion is adapted to abut the locking ring member and wherein the locking ring member is configured for screw-threaded engagement with the ferrule portion and is further arranged for frictional engagement against the flange portion of the spigot portion.

13. The end fitting assembly according to any preceding claim, wherein the ferrule portion further surrounds a flange portion of the spigot portion.

14. The end fitting assembly according to claim 11 when dependent upon any of claims 8 to 10 or to either of claims 12 or 13 when dependent upon claim 11, , wherein the flange portion of the spigot portion is arranged to transfer load to the ferrule portion via the locking ring member and the spigot portion and the ferrule portion are mechanically interlocked by the locking ring member.

15. The end fitting assembly according to claim 11 or to any of claims 12 to 14 when dependent upon claim 11, wherein the pipe is a composite pipe which comprises a bore and wherein the elastically deformable annular portion is configured for elastic radial deflection against the composite pipe bore as the pipe bore expands and contracts in use.

16. The end fitting assembly according to claim 11 or to any of claims 12 to 15 when dependent upon claim 11, wherein the elastically deformable annular portion of the spigot portion is provided with a circumferential raised formation around its distal end.

17. The end fitting assembly according to claim 16, wherein the circumferential raised formation is located at, or proximate, the terminal end of the elastically deformable annular portion.

18. The end fitting assembly according to either claim 16 or claim 17, wherein the circumferential raised formation of the elastically deformable annular portion has an outer diameter configured for interference fitment with the inner diameter of the pipe, wherein the circumferential raised formation is configured to create a localised highcontact pressure between the spigot portion and the pipe that is greater than the internal hydrostatic force within the pipe in use.

19. The end fitting assembly according to any preceding claim, wherein the ferrule portion is formed comprising an inside bore that is smaller in diameter than the diameter of the pipe to which it is to be fitted.

20. The end fitting assembly according to any preceding claim, wherein the ferrule comprises an outer diameter that is tapered from a location near its proximal end towards its distal end.

21. The end fitting assembly according to claim 20, wherein the taper has a taper angle of in the region of between 0.1oand 5o.

22. The end fitting assembly according to any preceding claim, wherein the ferrule portion comprises an inner surface and a terminal end and wherein the inner surface is provided with an undercut region extending inwardly from its terminal end.

23. The end fitting assembly according to claim 16, wherein the undercut region extends in the region of between 0.1 inches and 5 inches.

24. The end fitting assembly according to claim 8 or to any of claims 9 to 23 when dependent upon claim 8, wherein the locking ring member is locatable intermediate the spigot portion and the ferrule portion.

25. The end fitting assembly according to any preceding claim, wherein the locking ring member comprises a plurality of formations configured for engagement with a suitable tool for screwing and unscrewing said locking ring member into and from the ferrule portion, respectively.

Images