Connector assembly

Abstract

Connector assembly (200) for connecting two pipe sections, wherein the assembly comprises a first connector element (201) for adjoining a first pipe and a second connector element (202) for adjoining a second pipe. The first and second connector elements are couplable together, wherein An outwardly facing profile of the first and second connector elements, when coupled, defines a circumferential recess (204) for a locking ring (203) for locking the first and second connector elements together. The first and second connector elements comprise engaging elements (205) for engaging with the locking ring and the first and second connector elements further comprise respective overlapping members (206, 207) for forming a lap joint when the first and second connector elements are coupled, and wherein the engaging elements (205) of at least one of the connector elements (201) extend over the region of overlap of the overlapping members (206, 207).

Description

[0001] CONNECTOR ASSEMBLY

[0002] The present invention relates to a connector assembly for connecting two pipe sections and more particularly to fatigue enhancing stress mitigation features in such an assembly.

[0003] Background

[0004] Conventionally, tubular pipes are used throughout various stages of offshore construction, such as upstream oil and gas exploration. Such tubular pipes are often used as drill-pipe or casing and are manufactured in around 30ft sections. They are generally assembled at the rig site, either onshore or offshore, and are commonly used in the drilling and completion phases of constructing a well. However, tubular pipes are also used in other stages of exploration such as construction and assembly of the platform, the riser and subsea equipment.

[0005] In drilling operations, tubular pipes are assembled together to form a long drill string. Consecutive tubular pipes are in this respect added to the string as the drill bit drills deeper into the formation. However, in most drilling operations the drill bit and the tubular pipe must at some point be removed from the well. It is therefore necessary to use tubular pipes which can be assembled into a long string and then dismantled as the drill string is lifted back out of the well. To this end, each tubular pipe typically has a pin (male) end and a box (female) end, and these are typically threaded such that on making a connection between two tubular pipes, a threaded pin end will engage a threaded box end and secure the two tubular pipes together. The connection between the two tubular pipes is then usually tightened to a high torque to ensure a solid connection is made that will not readily allow the tubular pipes to become disengaged under operational conditions.

[0006] In the drilling phase of constructing an oil and gas well, casing strings are lowered into the well. Each casing is an assembly of tubular pipes which have been manufactured onshore and then are assembled at the rig site onshore or offshore. Unlike drill-pipe, casing is intended to be run into the well and cemented in place, rather than being removed and dismantled. Similarly, a casing string is assembled as a continuous string of individual tubular pipes, and connections must be made between each tubular pipe to form the string. The assembly process of such casings typically mirrors the assembly procedure adopted for drill pipe connections, where pin and box connectors are coupled together.

[0007] Engineering advancements have presented alternative ways of making the connection between two tubular pipes. One such option is shown in Fig 1, where a pipe connector assembly 100 is shown with two connector elements 101 , 102, a locking ring 103, and an optional stabbing guide 104. The connector elements 101, 102 are either machined as part of a pipe section, or they are attached separately, for example by welding them on to the pipe section. The connector element 101 , 102 and two pipe sections (not shown) can be brought together with the aid of the stabbing guide 104, which is welded or otherwise attached to one of the two connector elements 101,102, and helps to align the two connector elements 101, 102 when they are being brought together. The connector element 101 is engaged by the locking ring 103 such that they are securely mated. In this connection, the locking ring 103 comprises a split ring carried on the connector element 101 so that as the connector element 101 is lowered onto connector element 102, the locking ring deflects outwardly and snaps into position, securely coupling the connector elements 101 , 102 together.

[0008] In this connection, the connector elements 101 , 102 are shaped such that when coupled together they form a circumferential recess 105 in the exterior profile of the conjoined connector elements 101 , 102 within which the locking ring 103 is seated. Where the connector assembly 100 is used in high-stress applications, stress hotspots can develop at particular areas of the connector elements 101, 102 that may reduce the fatigue life of the connection.

[0009] In this connection, in our earlier application GB2576557, shown in Fig. 2, we presented an improved version of such a connector assembly 100A where internal corner regions 107 of a circumferential recess 108 are afforded an arcuate concave profile. In this regard, the arcuate concave profile moved areas of the connector elements away from the upper and lower faces 110 (and its corner edges 114) of the locking ring 103 and in this way sought to reduce or eliminate the stress hotspots, and thereby improve the fatigue life of the connector assembly and minimises fatigue failures. The locking ring 103 and connector elements of this arrangement are provided with engagement members in the form of inter-engaging teeth 112. The connector assembly includes a tapered pin and box connection 115 between the connector elements.

[0010] However, an object of the present invention is further improve such connector assemblies and moreover to overcome problems associated with expanding the desired application of such connector assemblies into new areas, such as offshore wind turbine generators.

[0011] Summary of Invention

[0012] According to a first aspect of the present invention, there is provided a connector assembly for connecting two pipe sections, the assembly comprising:- a first connector element for adjoining a first pipe; and a second connector element for adjoining a second pipe; the first and second connector elements being couplable together; an outwardly facing profile of the first and second connector elements, when coupled, defining a circumferential recess for a locking ring for locking the first and second connector elements together, wherein the first and second connector elements comprise engaging elements for engaging with the locking ring and wherein the first and second connector elements further comprise respective overlapping members for forming a lap joint when the first and second connector elements are coupled, wherein the engaging elements of at least one of the connector elements extend over the region of overlap of the overlapping members.

[0013] In this connection, the overlapping members overlap to a significantly greater extent compared with prior art arrangements, so as to deal more effectively with high bending moments associated with structures such as wind turbine, arising from thrust and wind effects.

[0014] Preferably, the extent of overlap of the overlapping members in the axial direction of the assembly is 30-70% of the extent of the circumferential recess in the axial direction of the assembly. As such, the connector assembly can more effectively deal with high bending moments. Further optionally, the extent of overlap of the overlapping members in the axial direction of the assembly is 40-60% of the extent of the circumferential recess in the axial direction of the assembly.

[0015] Preferably, end faces of the overlapping members are inclined from a plane perpendicular to the axis of the connector assembly and are received in corresponding recesses in the respective connector elements. Such inclined end faces further assist in effectively handling high bending moments applied to the connector assembly. The recesses are preferably provided as substantially V shaped grooves in the respective first and second connector elements.

[0016] Optionally, the end faces of the overlapping members are inclined at 60-70 degrees to the longitudinal axis of the connector assembly.

[0017] Preferably, the combined thickness of the overlapped members in the direction perpendicular to the longitudinal axis of the connector assembly is greater than the thickness of the body of the locking ring in the direction perpendicular to the longitudinal axis of the connector assembly. In this regard, the ratio of the combined thickness of the overlapping members to the thickness of the locking ring body is preferably in the range 1 :0.9 to 1 :0.7. In this regard, compared with the prior art the locking ring is relatively thinner, without significantly affecting the overall dimensions of the connector assembly.

[0018] Preferably, the upper and lower annular edge faces of the circumferential recess extend in a direction to maintain a spacing away from the upper and lower faces of the locking ring. In this connection, the upper and lower annular edge faces preferably have an arcuate concave profile. In this way, the prevalence of stress hotspots is reduced, improving the fatigue life of the connector assembly and minimises fatigue failures.

[0019] The spacing allows the material of the connector elements to creep or move under high loads without the connector elements coming into contact with the locking ring at the upper and lower annular edge faces. This reduces or eliminates the chance of stressing the material and so therefore improves the fatigue life of the connector elements. Additionally, the first and second connector elements may each comprise a plurality of engaging elements for engaging with engagement features provided to the locking ring. Such one or more engaging elements provide anchoring means by which the locking ring can secure and hold the two connectors together.

[0020] The engaging elements may comprise one or more protrusion portions and / or indent portions. In the case of an indent portion, this may have a concave profile, which may have an arcuate profile, and preferably comprises at least one ellipse in the cross section of the concave profile. Such a profile is intended to mitigate the damaging effect of high stresses that may be present at hotspots near the indent portion. This will preferably increase the lifespan of the component and reduce the likelihood of fatigue failure. Conveniently, the engaging elements may have a multicurved profile, and this is preferably formed of a plurality of ellipses. The plurality of ellipses is intended to reduce the effect of high stresses that may be present at hotspots near the indent portion and enhance the fatigue life of the connector assembly.

[0021] Incorporating a plurality of such engaging elements has the advantage of providing stronger engagement of the locking ring to the connector elements. Also, at a given service load, a plurality of engaging elements better distributes stresses within the connector assembly and reduces hotspots, which in turn enhances the fatigue life of the connector assembly.

[0022] The connector assembly may further comprise a locking ring attached to the first connector element, allowing the first connector element and locking ring to be brought into engagement with the second connector element, such that the locking ring will mate and resiliently engage the second connector element. To achieve this resilient engagement as the locking ring mates with the second connector element, the locking ring may take the form of a split ring. The split in the ring allows the ring to deflect outwardly on engagement with the second connector element and then snap into position on one or more engaging elements provided on the second connector element. In this way, the locking ring can be sufficiently resiliently deformable to be pushed over the second connector element and engage with its features such that it will securely hold both connector elements together. Conveniently, the locking ring has engagement features for engaging with engaging elements on the first and / or second connector elements.

[0023] According to a further aspect of the present invention there is provided connector assembly for connecting two pipe sections, the assembly comprising:- a first connector element for adjoining a first pipe; and a second connector element for adjoining a second pipe; the first and second connector elements being couplable together; an outwardly facing profile of the first and second connector elements, when coupled, defining a circumferential recess for a locking ring for locking the first and second connector elements together, wherein the first and second connector elements comprise engaging elements for engaging with the locking ring and wherein the first and second connector elements further comprise respective overlapping members for forming a lap joint when the first and second connector elements are coupled, wherein the circumferential recess has upper and lower corner edge profiles which are configured to afford a substantially consistent spacing around the adjacent upper and lower profiles of the locking ring.

[0024] In this regard, the upper and lower corner edge profiles maintain at least a minimum spacing between the first and second connector elements and the adjacent upper and lower profiles of the locking ring.

[0025] Preferably, the upper and lower corner edge profiles extend from respective uppermost and lowermost engagement members provided within the circumferential recess to the first and second connector elements.

[0026] Detailed Description

[0027] An embodiment of the invention will now be described, by way of example only, and with reference to the following drawings, in which;

[0028] Fig 1 shows a prior art tubular connector assembly;

[0029] Fig. 2 shows a further prior art tubular connector assembly; and

[0030] Fig. 3 shows a connector assembly in accordance with the present invention;

[0031] Referring now to Figure 3, this shows a connector assembly 200 for connecting two pieces of pipe together (not shown). The connector assembly 200 has three main components - two connector elements 201 , 202 and a locking ring 203. Each connector element 201, 202 can be attached to a piece of pipe in a known way, such as welding, or the connector elements 201 , 202 may be machined on the end of the pipe as an integral part of the pipe.

[0032] To securely connect two pieces of pipe together, a first piece of pipe with a first connector element 201 is fitted with a locking ring 203. The locking ring 203 is mounted to the first connector element 201 so that the two move together as the first connector element is lowered into engagement with the second connector element 202.

[0033] As the first and second connector elements are brought together, the locking ring 203 deflects outwards slightly, allowing it to pass over features of the second connector element and snap into engagement with the second connector element, thereby locking the first and second connector elements securely together.

[0034] In this connection, the outwardly facing profile of the first and second connector elements, when coupled, define a circumferential recess 204 for receiving the locking ring.

[0035] As shown, the first and second connector elements have engaging elements 205 for engaging with the locking ring. The first and second connector elements further comprise respective overlapping members 206, 207 for forming a annular lap joint when the first and second connector elements are coupled, wherein the engaging elements 205 of at least one of the connector elements 207 extend over the region of overlap of the overlapping members.

[0036] In this connection, the overlapping members 206, 207 overlap to a significantly greater extent compared with prior art arrangements, so as to deal more effectively with high bending moments associated with structures such as wind turbine, arising from thrust and wind effects.

[0037] In this respect, the extent of overlap of the overlapping members 206, 207 in the axial direction of the assembly is 30-70% of the extent of the circumferential recess 204 in the axial direction of the assembly. As such, the connector assembly can more effectively deal with high bending moments.

[0038] The extent of overlap of the overlapping members in the axial direction of the assembly in the embodiment is 48-50% of the extent of the circumferential recess in the axial direction of the assembly.

[0039] As shown, end faces 208, 209 of the overlapping members are inclined from a plane perpendicular to the axis of the connector assembly and are received in corresponding recesses in the respective connector elements. Such inclined end faces further assist in aligning the first and second connector element and can help to anchor the connector elements when coupled, thereby effectively handling high bending moments applied to the connector assembly. The recesses are preferably provided as substantially V shaped grooves in the respective first and second connector elements.

[0040] In the embodiment shown in Figure 3, the end faces of the overlapping members are inclined at 60-70 degrees to the longitudinal axis of the connector assembly.

[0041] As shown, the combined thickness “X” of the overlapped members in the direction perpendicular to the longitudinal axis of the connector assembly is greater than the thickness “Y” of the body of the locking ring in the direction perpendicular to the longitudinal axis of the connector assembly. In this regard, the ratio of the combined thickness of the overlapping members to the thickness of the locking ring body is preferably in the range 1:0.9 to 1 :0.7. In this regard, compared with the prior art the locking ring 203 is relatively thinner, without significantly affecting the overall dimensions of the connector assembly.

[0042] As shown, the upper and lower annular edge faces 210 of the circumferential recess extend in a direction to maintain a spacing away from the upper and lower faces of the locking ring, from the uppermost and lowermost engagement elements 205. In this connection, the upper and lower annular edge faces preferably have an arcuate concave profile. In this way, the prevalence of stress hotspots is reduced, improving the fatigue life of the connector assembly and minimises fatigue failures. In this connection, as described, the first and second connector elements 201, 202 when coupled have an outwardly facing profile which defines a circumferential recess 204 for seating the locking ring 203. The locking ring 203 may be attached to the first connector element 201 within a portion of circumferential recess 204 made up by the first connector element 201.

[0043] The two connector elements 201, 202 may be guided into alignment with the aid of one or more alignment features. In the present example shown in Figure 3, the alignment feature is formed from the shape of each connector element end 208, 209, which registers with the corresponding connector element end with which it will engage. Alternative ways of guiding the two connectors into alignment are also envisaged, such as, but not limited to, using a stabbing guide connected to one of the connector elements 201 , 202, as is present in the prior art example of Fig 1. The connector element ends are shown to be inclined in this regard to enhance the alignment and ultimate connection of the connector assembly.

[0044] The locking ring 203 comprises a split in the ring (not shown). The split allows the ring to deflect outwardly while the locking ring 203 moves down on to the second connector element 202. The locking ring 203 hence can increase in diameter very slightly to travel past features of the second connector element 202 and then engage securely within the portion of the circumferential recess 204 made up by the second connector element, as shown in Figure 3.

[0045] The circumferential recess 204 may be formed around the full circumference of the connector elements 201 , 202, or the circumferential recess 204 may be a recess formed over one or more parts of the circumference, but not necessarily extending continuously around the entire circumference. In the preferred embodiment shown in Fig 3, the circumferential recess 204 is a recess around the entire circumference, and the locking ring 203 is therefore an almost continuous ring around the entire circumference save for the relatively small split to allow for the locking ring 203 to deflect open and closed as described above.

[0046] In alternative embodiments, the locking ring 203 may be openable to place around the connector elements 201 , 202 and position within the circumferential recess 204. In this regard, the locking ring may have one or more axially orientated hinges allowing two semi-circular jaw-like sections thereof to open sufficiently to pass around the circumferential recess.

[0047] Alternatively, the locking ring may be hinged at one end from one of the connector elements 201, 202 such that the other end thereof can pivot down and snap into position once the connector elements 201, 202 are brought together.

[0048] As shown in Figure 3, the internal corner regions 210 are profiled to be spaced from the locking ring 203 when the locking ring 203 is brought into the locking position shown in Figure 3.

[0049] Referring to Figure 3, it can be seen that the connector elements 201, 202 each comprise engaging elements in the form of teeth 205. It should be appreciated that teeth 205 are just one way of providing an engaging element, and alternative elements that can perform the function of mating and engaging with the locking ring 203 are envisaged herein. The size and shape of the engaging elements must be registered with the size and shape of the feature on the locking ring 203 with which each engaging element will mate. In the embodiment shown in Figure 3, the teeth 205 mate with teeth 211 on the locking ring 203. There may be one or more engaging elements on each connector element 201, 202. Typically, there may be two or three engaging elements on each connector element 201 , 202, and a corresponding number of engagement features on the locking ring 203.

[0050] Compared with prior art arrangements the locking ring thickness has been reduced and the tooth profile of teeth 205 has been moved out radially. The tooth profile moving out radially assists with the strength in this area, with the mean diameter of the teeth moving out, the associated areas have also increased. The reduction in locking ring thickness does not compromise the strength of the locking ring.

[0051] When the connector assembly 200 is used in applications which cause high stresses within the material, stress hotspots may develop particularly at the internal corner regions 210 where the material has been shaped for receiving the locking ring 203. Typically, the locking ring 203 has sharp angles (around 90 degrees) at the shoulders and so the connector elements 201 , 202 are often manufactured with a similar angle for receiving the locking ring 203. The sharp angle at the internal corner regions 206 can create a stress hotspot in these regions. The internal corner regions 210 are afforded an arcuate concave profile, as this helps to distribute the stress and reduce or eliminate stress hotspots. The arcuate concave profile may be substantially elliptical in cross-section, and may be an elliptical scallop cut into the material of the connector element 201, 202 at the internal corner regions 210.

[0052] The arcuate concave profile allows for the internal corner regions 210 to be spaced apart from the locking ring 203 when the locking ring 203 is in the locked position, as shown in Fig 3. This space allows for the material of the connector elements 201 , 202 to creep or move under high loads without the connector elements 201 , 202 coming into contact with the locking ring 203 at the internal corner regions 210. This reduces or eliminates the chance of stressing the material in the internal corner regions, so therefore improves the fatigue life of the connector elements 201, 202. The arcuate ellipses also better distribute stresses in the connector than a sharp corner, which avoid creating a stress concentration, thus increasing the fatigue life of the connection.

[0053] Stress hotspots may also develop at the engaging elements of each connector element 201, 202. In this connection, each engaging element may comprise a protrusion portion and / or an indent portion. As shown, the protrusion portions register with corresponding indent portions of the locking ring. The indent portions register with corresponding protrusion portions of the locking ring. As shown in the embodiment of Figure 3, the indent portion of each engaging element is afforded a concave profile having a multi-curve arcuate profile, comprising two partial ellipses. In a similar fashion to the arcuate concave profile used in the internal corner regions 210, the adoption of this profile here helps to relieve stress hotspots, and improve the fatigue life of the connector element 201.

[0054] Improved fatigue life is always sought after, as it will help to increase the time to failure of the component and increase the fatigue life. The failure of a connection downhole may lead to everything below the connection being lost in the well which can be dangerous, expensive to fix and time consuming. The failure of a connection which is load bearing can have catastrophic safety implications, where the structure being supported may collapse. Often the fatigue life of a component is a very important factor which influences many other design considerations. For example, if it is calculated that the component at issue is likely to fail by fatigue, a different material may be selected which could be more expensive or compromise other design characteristic such as weight.

[0055] Improving the fatigue life through the design of the component not only means that it can withstand higher fatigue before failure, but also that other design considerations can be adjusted which may be beneficial in terms of, for example, reducing weight or reducing cost by using cheaper materials.

[0056] It will be understood that the various aspects of the present invention can be practiced alone or in combination with one or more of the other aspects, as will be appreciated by those skilled in the relevant arts. The various aspects of the invention can optionally be provided in combination with one or more of the optional features of the other aspects of the invention. Also, optional features described in relation to one aspect can typically be combined alone or together with other features in different aspects of the invention. Any subject matter described in this specification can be combined with any other subject matter in the specification to form a novel combination.

[0057] Various aspects of the invention are described in detail with reference to the accompanying figures. Still other aspects, features, and advantages of the present invention are readily apparent from the entire description thereof, including the figures, which illustrates a number of exemplary aspects and implementations. The invention is also capable of other and different examples and aspects, and its several details can be modified in various respects, all without departing from the scope of the present invention. Accordingly, each example herein should be understood to have broad application and is meant to illustrate one possible way of carrying out the invention, without intending to suggest that the scope of this disclosure, including the claims, is limited to that example. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Unless otherwise stated, dimensions and numerical values included herein are presented as examples illustrating one possible aspect of the claimed subject matter, without limiting the disclosure to the particular dimensions or values recited. All numerical values in this disclosure are understood as being modified by "about". All singular forms of elements, or any other components described herein are understood to include plural forms thereof and vice versa.

[0058] Language such as "including", "comprising", "having", "containing", or "involving" and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Thus, throughout the specification and claims unless the context requires otherwise, the word “comprise” or variations thereof such as “comprises” or “comprising” will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0059] Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention.

[0060] In this disclosure, whenever a composition, an element or a group of elements is preceded with the transitional phrase "comprising", it is understood that we also contemplate the same composition, element or group of elements with transitional phrases "consisting essentially of”, "consisting", "selected from the group of consisting of”, “including”, or "is" preceding the recitation of the composition, element or group of elements and vice versa. In this disclosure, the words “typically” or “optionally” are to be understood as being intended to indicate optional or non- essential features of the invention which are present in certain examples but which can be omitted in others without departing from the scope of the invention.

[0061] References to directional and positional descriptions such as upper and lower and directions e.g. “up”, “down” etc. are to be interpreted by a skilled reader in the context of the examples described to refer to the orientation of features shown in the drawings, and are not to be interpreted as limiting the invention to the literal interpretation of the term, but instead should be as understood by the skilled addressee. Whilst the present invention has been described in relation to an oil and gas / wind turbine implementation, it will be understood that the connector assembly may be utilised in other appropriate environments.

Claims

Claims:

1. A connector assembly for connecting two pipe sections, the assembly comprising:- a first connector element for adjoining a first pipe; and a second connector element for adjoining a second pipe; the first and second connector elements being couplable together; an outwardly facing profile of the first and second connector elements, when coupled, defining a circumferential recess for a locking ring for locking the first and second connector elements together, wherein the first and second connector elements comprise engaging elements for engaging with the locking ring and wherein the first and second connector elements further comprise respective overlapping members for forming a lap joint when the first and second connector elements are coupled, wherein the engaging elements of at least one of the connector elements extend over the region of overlap of the overlapping members.

2. A connector assembly as claimed in claim 1 , wherein the extent of overlap of the overlapping members in the axial direction of the assembly is 30-70%, and optionally 40-60%, of the extent of the circumferential recess in the axial direction of the assembly.

3. A connector assembly as claimed in claim 1 or 2, wherein end faces of the overlapping members are inclined from a plane perpendicular to the axis of the connector assembly and are received in corresponding recesses in the respective connector elements.

4. A connector assembly as claimed in claim 3, wherein the recesses are preferably provided as substantially V shaped grooves in the respective first and second connector elements.

5. A connector assembly as claimed in claim 3 or 4, wherein the end faces of the overlapping members are inclined at 60-70 degrees to the longitudinal axis of the connector assembly.

6. A connector assembly as claimed in any preceding claim, wherein the combined thickness of the overlapped members in the direction perpendicular to the longitudinal axis of the connector assembly is greater than the thickness of the body of the locking ring in the direction perpendicular to the longitudinal axis of the connector assembly.

7. A connector assembly as claimed in claim 6, wherein the ratio of the combined thickness of the overlapping members to the thickness of the locking ring body is preferably in the range 1:0.9 to 1 :0.7.

8. A connector assembly as claimed in any preceding claim, wherein upper and lower annular edge faces of the circumferential recess extend in a direction to maintain a spacing away from adjacent upper and lower faces of the locking ring.

9. A connector assembly as claimed in claim 8, wherein the upper and lower annular edge faces have an arcuate concave profile.

10. A connector assembly as claimed in any preceding claim 1, wherein the first and second connector elements each comprises one or more engaging elements for engaging with engagement features provided to the locking ring.

11. A connector assembly as claimed in claim 10, wherein the one or more engaging elements may comprise one or more protrusion portions and / or one or more indent portions.

12. A connector assembly as claimed in claim 11 , wherein in the case of an indent portion, this has a concave arcuate profile.

13. A connector assembly for connecting two pipe sections, the assembly comprising:- a first connector element for adjoining a first pipe; and a second connector element for adjoining a second pipe; the first and second connector elements being couplable together; an outwardly facing profile of the first and second connector elements, when coupled, defining a circumferential recess for a locking ring forlocking the first and second connector elements together, wherein the first and second connector elements comprise engaging elements for engaging with the locking ring and wherein the first and second connector elements further comprise respective overlapping members for forming a lap joint when the first and second connector elements are coupled, wherein the circumferential recess has upper and lower corner edge profiles which are configured to afford a substantially consistent spacing around the adjacent upper and lower profiles of the locking ring 14. A connector assembly as claimed in claim 13, wherein the upper and lower corner edge profiles extend from respective uppermost and lowermost engagement members provided within the circumferential recess to the first and second connector elements.

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