Apparatus for servicing a structure

Abstract

An apparatus for servicing an elongate structure 24 has a bypass module 12 which enables a servicing module 1 to pass an obstruction 25 on the structure. Bypass module 12 and servicing module 1 are ea

Description

Field of the Invention

[0001] The present invention relates to apparatus for servicing a structure, such as a support structure including but not limited to marine support structures such as risers, conductors, caissons piles, or legs for marine platforms, jetties or wharves, or pipes, and land-based or offshore structures such as wind turbine towers. Background of the Invention

[0002] Marine support structures typically suffer from ageing and degradation, particularly in the 'splash zone', which is the part of the structure that is periodically covered and uncovered by water, for example as a result of tidal range, wave action and / or splashing. Ageing may include corrosion and physical damage caused by wave action and impacts. Degradation may include accumulation of marine growth, such as weed, barnacles etc.

[0003] Marine support structures therefore need to be serviced, for example by cleaning, inspection, and coating or painting, to ensure continued performance and to extend their life. Conventionally, servicing is carried out by divers but this can be extremely difficult and hazardous, particularly in the splash zone, and is often not fully effective. As well as marine and offshore structures, land-based structures such as wind turbine towers also need to be serviced. In some cases, a structure to be serviced may include an obstruction such as a clamp or cross-brace, which may present an obstacle to servicing the structure.

[0004] The applicant's patent publication WO 2023 / 285814 Al discloses a bypass module for connection in series along an elongate structure between a first module and a second module, each of which may be selectively closed around the structure or opened to enable removal from the structure, and each of which is driveable along the structure. The bypass module is actuable to move the first and second modules relative to each other in a perpendicular direction to the elongate structure towards or away from the elongate structure, so that the second module is moved in the perpendicular direction away from the structure while the first module is closed around the structure and the first module is drivable along the elongate structure so as to drive the second module past an obstruction on the elongate structure.

[0005] Although the above-described bypass module provides an effective method of bypassing an obstruction on an elongate structure, it is desirable in some circumstances to use a simpler method that does not require two or more drive or service modules. Statements of the Invention

[0006] Aspects of the invention are defined by the accompanying claims.

[0007] According to one embodiment, there is provided a bypass module enabling a drive and / or servicing module (hereafter referred to as a servicing module) to pass an obstruction on an elongate structure to be serviced. The servicing module may be selectively closed around the elongate structure to be serviced, and opened to release the servicing module from the elongate structure.

[0008] The bypass module and servicing module are each supported alongside the elongate structure, for example by a respective at least one cable or the like which can be raised or lowered along the elongate structure by means of a respective winch or other means.

[0009] The bypass module may comprise a base connected to arms between which the structure can be received. The base may also include means, such as one or more members, water jets or a magnetic drive, actuable to push at least a part of the bypass module perpendicularly away from the elongate structure, preferably while retaining the elongate structure between the arms so that the bypass module can move back towards the elongate structure when no longer pushed away from the structure.

[0010] The bypass module has one or more channels which the servicing module's cables pass through, such that pushing at least part of the bypass module away from the structure causes the one or more channels to move away from the structure and thereby causes the servicing module, when released from the structure, to move away from the structure.

[0011] In this way, the servicing module may bypass an obstacle on the structure by opening and being moved away from the structure by the action of the bypass module. The servicing module may then be raised or lowered past the obstacle, before being moved back towards the structure and closed around the structure. Optionally, the bypass module may then be moved past the obstacle if still required.

[0012] One advantage of the bypass module is that it maintains the position of the servicing module close to the elongate structure even when the servicing module is opened. This may help to prevent the servicing module from coming adrift from the elongate structure such that the servicing module cannot be reattached in situ to the elongate structure.

[0013] The servicing module may comprise a cage or frame comprising two or more segments or sections movably or pivotably connected together, for example by one or more hinges, so that the cage or frame may be opened to fit around the elongate structure to be serviced and to allow removal from the elongate structure, and closed to secure the frame or cage around the elongate structure. The servicing module may be selectively opened and closed by a drive, such as a hydraulic ram or electric motor, mounted on the servicing module. In this way, a drive which is used to open and close the servicing module around the elongate structure may be actuated to allow the servicing module to pass an obstacle on the structure, and no additional drive to open and close the servicing module is required in the bypass module. Brief Description of the Drawings

[0014] Specific embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view from above of a servicing module in a first example; Figure 2 is a top view of the servicing module; Figure 3 is a side view of the servicing module; Figure 4 is a side elevation of a tracked drive module of the servicing module; Figure 5 is a perspective view from above of the tracked drive module; Figure 6 is a first perspective view from above of a servicing module in a second example; Figure 7 is a second perspective view from above of the servicing module in the second example; Figure 8 is a first side elevation of a bypass module in an embodiment of the invention; Figure 9 is a second side elevation of the bypass module; Figure 10 is a top view of the bypass module with guide wheels retracted; Figure 11 is a top view of the bypass module with guide wheels extended; Figure 12 is a top view of the bypass module with arms open; Figure 13 is a perspective view from above of the bypass module with guide wheels retracted; Figure 14 is a perspective view from above of the bypass module with guide wheels extended; Figure 15 is a perspective view from above of the bypass module with arms open; Figure 16 is a flow chart showing a method of operation of the bypass module with the servicing module; Figures 17 - 26 are perspective views showing the operation of the bypass module and servicing module at the respective step of the flow chart in Figure 16. Detailed Description of Embodiments

[0015] In the description below, the orientation of the apparatus will be described as assembled around a vertically oriented or inclined elongate structure 24, such as a pile, pipe, mast or tower. 'Radial' and 'perpendicular' refer to a direction perpendicular to a notional central vertical axis of the support structure, and 'parallel' to a direction parallel to that axis. 'Circumferential' refers to a circumference around that axis.

[0016] Where dimensions are shown in the drawings, these are given in millimetres. The dimensions are not limiting on the size of specific embodiments and are provided purely by way of example.

[0017] For clarity, not all instances of a particular part are indicated by reference numerals in the drawings. It will be understood by inspection of the drawings as a whole which parts are referred to. Similar parts between different embodiments are indicated by the same reference numeral.

[0018] A first example of a servicing module 1 is described below with reference to Figures 1 to 5. The servicing module 1 comprises a cage or frame 33 comprising cage or frame segments la, lb connected together at frame connection points 2a, 2b. At the first connection point 2a frame segments la, lb are pivotally connected, for example by a hinge. At the second frame connection point 2b, segments la, lb are removably connected together, for example by removable pins or locking mechanisms such as locking cylinders. In use, the frame segments la, lb are assembled around the elongate structure 24 to be serviced. The frame segments la, lb may be opened about the hinge such that the frame 33 fits around the elongate structure 24 and closed to secure the frame 33 around the structure 24. A remotely controlled hydraulic ram or electric motor mounted on the frame 33 may be used to selectively open and close the frame 33.

[0019] The frame segments la, lb include lifting points 3 situated around the upper edge of the frame 33 for attachment of cables 26a, 26b or the like, allowing the servicing module 1 to move in either direction (e.g. upwards or downwards) along the structure 24. In this example, there are three lifting points 3, situated around the upper edge of the servicing module 1. Not all lifting points 3 may be used for moving the servicing module 1 along the elongate structure 24; other uses of the lifting points 3 include lifting the frame segments la, lb onto the structure 24 and retrieving them after use. Preferably, each frame segment la, lb is light enough to be manually lifted into position.

[0020] The cables 26a, 26b may be connected to a winch or other means for raising or lowering the cables 26a, 26b. The winch may be arranged for lowering the servicing module 1 into position and / or for recovering the servicing module 1 after use. In the case where the elongate structure 24 has a cross-brace 25 or other obstacle that extends laterally from the elongate structure 24,, the cables 26a, 26b are oriented so that the second frame connection point 2b, at which the frame 33 may be opened, is aligned with the cross-brace 25.

[0021] The frame 33 comprises an upper support / flange 4 and a lower support / flange 5, interconnected by struts 6. In this example, the upper and lower supports 4, 5 are circular in shape and coaxial. The struts 6 extend generally vertically between the upper and lower supports 4, 5. The upper support 4, lower support 5 and struts 6 are preferably substantially rigid and are connected together so that the frame 33, when assembled, is substantially rigid.

[0022] The servicing module 1 may include tracked drive modules 7a, 7b, 7c which include index plates 9 which may be adjustable so as to adjust the angle of attack of the tracks 8 on the drive modules 7a, 7b, 7c relative to the elongate structure 24, to prevent the servicing module 1 from spiralling around the elongate structure 24 and the cables 26a, 26b becoming entangled. The tracked drive modules 7a, 7b, 7c also include adjustable tension springs 11 for varying the pressure between the tracks 8 and the elongate structure 24.

[0023] The upper and / or lower supports 4, 5 may be arranged for mounting tool(s) for servicing the elongate structure 24. Both the upper and lower supports 4, 5 may include a latch mechanism, used to attach the tool(s) to the servicing module 1. By moving the servicing module 1 up and down the elongate structure 24, tools may reach substantially any part of the external surface of the elongate structure 24, at least within the splash zone and subject to any restrictions due to hydraulic lines and the like.

[0024] The tool(s) may be movably mounted on the supports 4, 5 to allow movement of the tool(s) relative to the supports 4, 5. For example, the tool(s) may be reciprocally driveable towards and away from the elongate structure 24, for example in a radial direction.

[0025] Examples of the tool(s) that may be mounted either singly or together on the upper and lower supports 4, 5, and which may be interchangeable, include: A high-pressure water nozzle for cleaning the surface of the elongate structure 24 A wall thickness measuring probe for measuring the wall thickness of the elongate structure 24, for example using Pulsed Eddy Current (PEC), Alternating Current Field Measurement (ACFM) or other inspection technologies including laser scanning, X Ray and ultrasound A video camera for inspection of the elongate structure 24 and / or of the surroundings A clearance sensor for sensing clearance from the surface of the elongate structure 24 A painting tool, such as a paint roller, spray nozzle(s) or brushes, for painting the surface of the elongate structure 24 A wrapping tool for applying a protective wrapping to the elongate structure 24 A cutting tool for cutting a part of the elongate structure 24, for example using high-pressure abrasive cutting or laser cutting or drilling.

[0026] Figures 6 to 7 show a second example of a servicing module 1. The second example differs from the first example in that the tracks 8 on the drive modules 7a, 7b, 7c may be replaced by a pair of wheels 20. At least one of the wheels 20 may be driveable reciprocally in either one of opposite directions (e.g. forward and backward) so as to move the servicing module 1 respectively up and down the elongate structure 24. Others of the wheels 20 may not be driven, but may freely rotate, preferably independently of each other, so as to enable movement of the servicing module 1 up and down the elongate structure 24. The wheels 20 may have contact surfaces arranged to enhance traction against the elongate structure 24 and / or reduce wear to the wheels 20.

[0027] The second example also includes a rack and pinion circumferential track 13a, 13b carrying a tool carriage 40, which may be mounted on either or both of the upper and lower supports 4, 5. The tool carriage 40 may have a drive gear which, when driven, moves the tool carriage 40 circumferentially around the respective upper / lower support 4, 5. The tool carriage 40 may be driveable circumferentially through approximately 360°, but preferably the movement of the tool carriage 40 is limited to one complete rotation.

[0028] The tool carriage 40 is arranged to carry one or more tool(s) to service the structure 24. By moving the frame 33 up and down the elongate structure 24 using the wheels 20 and / or cables 26a, 26b, and moving the tool carriage 40 circumferentially around the elongate structure 24, the tool(s) may reach substantially any part of the external surface of the elongate structure 24, at least within the splash zone and subject to restrictions due to hydraulic lines and the like.

[0029] There may be load sensors attached to the tool carriage 40 as well as / instead of the latch mechanism so as not to damage the sensors when touching the structure to extract data, for example PAUT data.

[0030] In the second example, lifting points 3 may be situated in the centre or on the body of the frame 33 between the upper support 4 for attachment of cables 26a, 26b or the like to prevent the cables 26a, 26b becoming entangled with the rack and pinion circumferential track 13a and / or stopping the movement of a tool carriage 40.

[0031] Figures 8-15 show a bypass module or clamp / cross-brace bypass shoe (CBS) 12 in an embodiment of the invention. The CBS 12 enables the servicing module 1 to pass an obstacle such as a clamp or cross-brace 25.

[0032] The CBS 12 comprises lifting points 14 for attachment of cables 27a, 27b which move the CBS 12 up and down the elongate structure 24. The cables 27a, 27b are connected to a winch or winches located above the structure 24. In this example, there are two lifting points 14, situated on either side of the CBS 12. These are located so as to keep the CBS 12 balanced and aligned with the structure 24. Other uses of lifting points 14 include lifting the CBS 12 onto the structure 24 and retrieving the CBS 12 after use. Preferably, the cables 27a, 27b are positioned so that an open or openable side of the CBS 12 is aligned with the clamp or crossbrace 25.

[0033] In an alternative embodiment, the CBS 12 may include other means for moving along the elongate structure, such as one or more drive modules as described in the examples above. However, the use of cables 27a, 27b simplifies the arrangement.

[0034] The CBS 12 comprises a base 31 connected to arms 15a, 15b having inner surfaces arranged to contact and slide along the surface of the elongate structure 24. The ends of the arms 15a, 15b opposite the base 31 may be spaced apart allowing the elongate structure 24 to pass between them, and may be open or opened to allow the CBS 12 to pass an obstacle such as a cross-brace 25.

[0035] The arms 15a, 15b are preferably moveable apart to facilitate passing the obstacle. For example, they may be pivotally connected to the base 31 at respective pivot points 16a, 16b. Preferably, the arms 15a, 15b are biassed together, for example by sprung hinges 17 to bring the arms 15a, 15b into contact with or towards the elongate structure 24 and to allow the arms 15a, 15b to flex outwardly and be pushed apart by a flange 28 to pass a cross-brace 25 on the elongate structure 24. The sprung hinges 17 may comprise compression springs 18 allowing the arms 15a, 15b to be flexed and pushed open so that the width between the arms 15a, 15b is approximately the diameter of the flange 28 of the cross-brace 25, then closed after passing the cross-brace 25 so that the width between the arms 15a, 15b is approximately the diameter of the elongate structure 24. The inner surfaces of the arms 15a, 15b may include chamfered upper and / or lower surfaces 19 to assist in opening the arms 15a, 15b as they meet the flange 28 of the cross-brace 25. In alternative embodiments, the arms 15a, 15b of the bypass module 12 may include means, such as a hydraulic cylinder or a motor with gears, actuable to open and close the arms 15a, 15b so as to pass the cross-brace 25.

[0036] Skid pads 29 on the inner surfaces of the arms 15a, 15b may provide lateral stability to the apparatus and a suitable contact surface for moving the CBS 12 along the elongate structure 24. The skid pads 29 can be replaced so as to avoid wear on the arms 15a, 15b.

[0037] The base 31 includes means actuable to push the base 31 away from the structure 24, for example a hydraulic cylinder 22 or electric motor connected to guide wheels 21 by linear guides 30 so as to move the guide wheels 21 reciprocally towards and away from the base 31. When the hydraulic cylinder 22 is activated, the guide wheels 21 are driven towards the elongate structure 24, so as to push the CBS 12 away from the elongate structure 24. When the hydraulic cylinder 22 is deactivated, the guide wheels 21 are retracted towards the base 31 to allow the CBS 12 to move towards the elongate structure 24, for example due to the suspension of the CBS 12 by the cables 27a, 27b arranged adjacent to the structure 24. In other embodiments, the hydraulic cylinder 22 and guide wheels 21 may be replaced by a hydraulic or electric thruster motor or a magnetic repulsion system to push the CBS 12 away from the structure 24.

[0038] Preferably, the distance by which the base 31 is pushed away from the structure 24 is such that the distal ends of the arms 15a, 15b remain either side of the structure 24, such that the CBS 12 remains laterally aligned with the structure 24 and does not drift away from the structure 24. Additionally, the distal ends of the arms 15a, 15b may extend towards or even into contact with each other so as to prevent the CBS 12 from detaching from the structure 24 unless the arms 15a, 15b are moved apart.

[0039] The CBS 12 includes sheaves 32a, 32b through which the servicing module's cables 26a, 26b pass so as to ensure the CBS 12 and the servicing module 1 are vertically aligned, with the servicing module 1 being below the CBS 12. The sheaves 32a, 32b ensure the servicing module 1 is moved away from the elongate structure 24, by lateral movement of the servicing module's cables 26a, 26b, when the CBS 12 is pushed away from the elongate structure 24. The cables 26a, 26b can run through the sheaves 32a, 32b so that the vertical separation of the servicing module 1 and the CBS 12 can be adjusted. Rigging guides 23 are located on the inner surface of the CBS 12 to guide the cables 26a, 26b through the sheaves 32a, 32b to help the cables 26a, 26b to move smoothly through the CBS's sheaves 32a, 32b when the servicing module 1 and / or CBS 12 is moving vertically.

[0040] In a first embodiment, the sheaves 32a, 32b may be rings, blocks or pulleys through which the respective cables 26a, 26b can be threaded. Preferably, the sheaves 32a, 32b can be opened to allow attachment around the cables 26a, 26b without the need to thread the ends of the cables 26a, 26b through the sheaves 32a, 32b. This allows attachment of the CBS 12 to the cables 26a, 26b when the servicing module 1 is already closed around the structure 24.

[0041] In one or more alternative embodiments only the sheaves 32a, 32b, or a part of the CBS 12 that includes the sheaves 32a, 32b, are moved away from the structure 24 while at least another part of the CBS 12 remains close to or in contact with the structure. For example, in the above described embodiment in which the distal ends of the arms 15a, 15b extend towards or in contact with each other, the distal ends of the arms 15a, 15b move towards the elongate structure 24 as the base 31 moves away from the structure 24. In that embodiment, the opening between the arms 15a, 15b may be elongate in a direction perpendicular to the structure 24 so that the base 31 (or other part having the sheaves 32a, 32b attached thereto) can be moved away from the structure 24 while allowing the distal ends of the arms 15a to remain positioned around the structure 24.

[0042] In some embodiments, the base 31 may be hinged to assist with the assembly of the CBS 12 on the elongate structure 24. The hinge may allow the arms 15a, 15b to open about the hinge, allowing the arms 15a, 15b to fit around the elongate structure 24. When around the elongate structure 24, the arms 15a, 15b may close about the hinge so that the inner surfaces of the arms 15a, 15b are in contact with the elongate structure 24.

[0043] A method of operation of the servicing module 1 and CBS 12 so as to pass an obstacle such as a cross-brace 25 is shown in the flow chart of Figure 16. Steps SI - S10 correspond respectively to Figures 17 - 26. The opening, closing, driving, extending and retracting steps may be controlled manually, automatically or semi-automatically, for example by means of a remote-control unit and / or controller with the position and state of the modules being detected by one or more sensors and / or by visual inspection.

[0044] At step SI, the servicing module 1 is installed on an elongate structure 24 to be serviced such as a pipe / riser to which a cross-brace 25 is attached. The servicing module 1 is located above the cross-brace 25. The CBS 12 is installed on the elongate structure 24 above the servicing module 1 by positioning the arms 15a, 15b either side of the structure 24, with the servicing module's cables 26a, 26b threaded through the sheaves 32a, 32b on the CBS 12. In this state, the servicing module 1 is closed around the pipe 24. At step S2, the servicing module 1 moves down the pipe 24, lowered on its cables 26a, 26b and arrives at the crossbrace 25. At step S3, the frame 33 is opened about its hinges by its drive, such as a hydraulic ram or electric motor.

[0045] At step S4, the CBS's hydraulic cylinder 22 is activated, extending the guide wheels 21 and pushing the CBS 12 away from the structure 24 while still retaining the structure 24 between the ends of the arms 15a, 15b so as to provide lateral stability. Because the frame 33 is open and the servicing module's cables 26a, 26b pass through the sheaves 32a, 32b on the CBS 12, the servicing module 1 also moves away from the structure 24. At step 85, the servicing module 1 is lowered by its cables 26a, 26b until it has passed the cross-brace 25. At step 86, the CBS's hydraulic cylinder 22 is inactivated, retracting the guide wheels 21, causing the CBS 12 to move back towards the structure 24. The servicing module's cables 26a, 26b pass through the CBS 12 aligning the servicing module 1 and the CBS 12 so therefore the servicing module 1 also moves back towards the structure 24. At step 87, the frame 33 is closed about its hinges around the structure 24 by its drive. The servicing module 1 has now bypassed the cross-brace 25 and is ready to service the structure 24.

[0046] At step 88, the CBS 12 moves down the structure 24, lowered by its cables 27a, 27b, and arrives at the cross-brace 25. At step 89, the CBS's arms 15a, 15b are flexed and pushed open at the pivot points 16a, 16b by contact with the flange 28 of the cross-brace 25 so that the width between the arms 15a, 15b is slightly larger than the diameter of the cross-brace 25 so as to fit around the cross-brace 25. The cables 27a, 27b move the CBS 12 down the structure 24 past the cross-brace 25. At step S10, the CBS 12 has moved over and past the cross-brace 25 and its arms 15a, 15b have flexed back wherein the width between the arms 15a, 15b is slightly larger than the diameter of the structure 24. Both the CBS 12 and the servicing module 1 have passed the cross-brace 25 and can continue moving down the structure 24 to service the structure 24.

[0047] Hence, by the addition of the CBS 12, the servicing module 1 is able to bypass obstructions such as a cross-brace 25.

[0048] The above embodiments are designed for servicing a circular cylindrical elongate structure 24 such as a pile. Therefore the frame 33 is approximately circular cylindrical, having an inner diameter slightly larger than the diameter of the elongate structure 24. Furthermore, the CBS 12 may be U-shaped, having a width between the arms 15a, 15b slightly larger than the diameter of the elongate structure 24. Alternative embodiments may have alternative shapes and sizes to match the type of elongate structure 24 which they are designed to service. For example, a square or rectangular cylindrical frame 33 may be used in an embodiment designed for servicing a square or rectangular cylindrical elongate structure 24.

[0049] The above embodiments are designed for servicing a vertical or near-vertical elongate structure 24. Alternative embodiments may be designed for servicing a non-vertical structure, for example a horizontal structure, by means of a suitable support such as a cable track that brings the servicing module 1 and CBS 12 into proximity with the elongate structure 24 but allows them to move away from the elongate structure 24.

[0050] In some embodiments where there is just one obstacle to bypass, for example a cross-brace 25, steps S8 and 89 may not be necessary to service the structure 24. After step 87, when the servicing module 1 has bypassed the cross-brace 25 and is closed around the elongate structure 24, the servicing module 1 may continue to move down the elongate structure 24 independently of the CBS 12 to finish carrying out its service and then be removed from the elongate structure 24 when the service has been completed. The CBS 12 is therefore not required again as there are no more obstacles 25 for the servicing module 1 to bypass. Therefore, the CBS 12 may be retrieved and detached from the elongate structure 24 and the servicing module's cables 26a, 26b whilst the servicing module 1 finishes its servicing.

[0051] In other embodiments, the servicing module 1 may not fully enclose the elongate structure 24 therefore may not have to be opened and closed by a drive. However, the bypass module 12 still provides stability through its engagement of the elongate structure when the servicing module 1 is disengaged from the elongate structure 24.

[0052] In some embodiments, the servicing module 1 may be connected to one or more additional modules, such as servicing and / or drive modules. The additional modules would also be able to bypass an obstacle 25 in the same way as the servicing module 1 by opening and closing around the structure 24 and being moved away from the structure 24 by the movement of the CBS 12.

[0053] In some embodiments more than one CBS 12 may be provided in series, to pass multiple clamps.

[0054] The components of any of the embodiments may be provided as a kit of parts to facilitate assembly around the elongate structure 24.

[0055] The servicing module 1 and / or CBS 12 are preferably controlled by one or more remote control units which allows control of some or all of the functions described above, preferably by means of corresponding user actuable controls. The remote control unit may be connected by a wired or wireless connection to a controller of the functions described above. Power for driving the functions may be provided by a power supply under the control of the controller. Alternatively or additionally, some or all of the functions may be controlled automatically by means of a controller which may either be remote or local to the servicing module 1 and / or CBS 12.

[0056] Preferably, the frame segments la, lb are constructed of aluminium tube so as to be lightweight. For example, the mass of the apparatus, excluding hydraulic or electrical lines, may be in the range 200-300 kg.

[0057] The above embodiments may be used in a marine or aquatic splash zone, or at a 5 shallow depth below the surface, such as 10 metres. The embodiments may be modified for operation below 10 metres in depth, for example by the use of suitable hydraulic seals. The embodiments may be used for servicing pipes, to the extent that they are not impeded by the support of the pipes. Alternative embodiments may be used for servicing non-marine or onshore support structures, such as wind turbines or radio masts. 10

[0058] Alternative embodiments of the invention, which may be apparent to the skilled person on reading the above description, may fall within the scope of the invention as defined by the accompanying claims.

Claims

1. Apparatus for servicing an elongate structure, comprising a bypass module for connection to a servicing module for servicing the elongate structure, wherein the bypass module comprises:a base connected to at least two arms having an opening therebetween for receiving the elongate structure;at least one channel arranged to allow at least one first line to pass therethrough, the at least one first line for supporting the servicing module and allowing the servicing module to move along the elongate structure, so as to align the servicing module with the bypass module; andmeans configured to move the at least one channel away from the elongate structure so as to move the servicing module away from the elongate structure, thereby enabling the servicing module to pass an obstruction on the elongate structure.

2. Apparatus of claim 1, wherein the bypass module includes at least one attachment point for attaching a corresponding second line for supporting the bypass module and allowing the bypass module to move along the elongate structure;3. Apparatus of claim 1 or claim 2, where the means configured to move the at least one channel comprises an extendable and retractable member configured to contact the elongate structure when extended and thereby push the base away from the elongate structure, the at least one channel being connected to the base.

4. Apparatus of any preceding claim, wherein the arms are moveable away from each other to allow the bypass module to pass the obstruction.

5. Apparatus of claim 4, wherein the arms are pivotally attached to the base to allow the arms to move away from each other.

6. Apparatus of claim 4 or 5, wherein the arms are biased against the movement away from each other.

7. Apparatus of any one of claims 4 to 6, wherein inner upper and / or lower surfaces of the arms are chamfered so as to move the arms away from each other when the arms contact the obstruction.

8. Apparatus of claim 7, wherein inner surfaces of the arms include pads for contacting the elongate structure.

9. Apparatus of any preceding claim, wherein the extendable and retractable member has one or more rolling parts arranged to contact the elongate structure.

10. Apparatus of any preceding claim, wherein the at least one channel comprises one or more sheaves.

11. Apparatus of any preceding claim, including one or more guides to guide the at least one first line through the at least one channel.

12. Apparatus of any preceding claim, including said servicing module.

13. Apparatus of claim 12, wherein the servicing module is arranged to be selectively closed around the elongate structure and opened to pass the obstruction on the elongate structure.

14. Apparatus of claim 13, wherein the servicing module comprises a frame consisting of a plurality of frame segments pivotally connected together.

15. Apparatus of claim 14, wherein the frame is arranged to carry one or more tools for servicing the structure.

16. A method of operation of the apparatus of any one of claims 13 to 15, the method comprising:a. opening (S3) the servicing module to release the servicing module from the elongate structure;b. moving (84) the at least one channel away from the elongate structure and thereby moving the servicing module away from the elongate structure;c. moving (S5) the servicing module past an obstacle by means of the one or more second lines;d. allowing (S6) the at least one channel to move towards the elongate structure and thereby move the servicing module towards the elongate 5 structure; ande. closing (S7) the servicing module around the elongate structure.

17. The method of claim 16, further including:a. moving (S8) the bypass module along the elongate structure to the obstacle10 by means of the one or more first lines; andb. moving (S9) the bypass module past the obstacle by means of the one or more first lines.s

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