“BUOYANCY MODULE”

FIELD OF THE INVENTION

[0001] The present invention relates to a buoyancy module.

[0002] In particular, the present invention relates to a buoyancy module for attaching to a pipe or cable for use underwater.

BACKGROUND

[0003] Underwater pipes and cables are used in various applications, and can be fitted with one or more buoyancy modules.

[0004] Where a pipe or cable travels from a point near the surface to a point at greater depth for example, a large length of pipe can be unsupported, between the upper end and a point at which it becomes supported at greater depth, for example by the sea bed.

[0005] The stresses imparted on the upper end support in this situation are significant, to the extent that laying unsupported sections of a particular length is not possible and requires intermediate supports.

[0006] Pipes or cables are typically laid from a ship on the surface, and therefore the limited depth at which pipes of cables can be laid without intermediate support results in a very restricted range of operation.

[0007] Buoyancy modules are commonly used to provide intermediate support, and are typically fitted at pre-determined points along the length of a pipe as it is laid.

[0008] The buoyancy modules are designed to provide a desired amount of buoyancy at the known points at which they are attached. [0009] Buoyancy modules allow a pipe or cable to follow a desired trajectory or path, and reduce the forces imparted on the ship or equipment at the upper end of the pipe.

[0010] Buoyancy modules are typically comprised of two halves of the module, which wrap around a clamp affixed to the pipe.

[0011] The clamp is fixed to the pipe to prevent axial movement of the buoyancy module relative to the pipe.

[0012] The two halves may then be held together using adjustable straps around the two halves, which are then tightened around the clamp and the pipe.

[0013] A known process of fitting buoyancy modules involves feeding the pipe toward the exit of the ship.

[0014] The two halves of the module are suspended in the work area using standard lifting equipment such as winches and hoists.

[0015] The crew position the two halves around the pipe. The use of two halves of a module, and the requirement to join these around the pipe and clamp results in a number of pinch points, liable to cause injury to crew members.

[0016] The large masses being suspended, possibly on a boat susceptible to movement of the ocean, provides a dangerous environment for the crew.

[0017] The straps are then passed around the two halves and tightened, before the pipe is progressed toward the sea bed, and the process begins again further along the pipe.

[0018] Buoyancy modules can be of significant size and mass, ranging from around 0.5m in length to around 4m.

[0019] The environment in which this process is carried out is typically on a ship, around, or close to, a point of egress of the pipe. The crew involved can require up to 7 people, in an unsteady environment involving the large masses of the module halves suspended on hoists. [0020] The result of each, or a combination, of these factors, is a very dangerous environment for a large crew of people to work.

[0021] Additionally, the process of positioning, attaching and fixing the modules can be very time consuming, even with a large crew this can take over 20 minutes per module.

[0022] The costs of running a ship installing buoyancy modules are extremely high, therefore the time taken to install modules represents a significant cost and results in a high cost per installed module.

[0023] The present invention attempts to overcome at least in part the aforementioned disadvantages of previous buoyancy modules by providing a buoyancy module which is safer and / or quicker to install.

SUMMARY OF THE INVENTION

[0024] In accordance with one aspect of the present invention there is provided a buoyancy module for installing on a member, the member having an axis and a clamp, and the buoyancy module comprising; a first module piece comprising a elongate recess configured to receive the member along its axis, and a secondary recess configured to receive the clamp, a locking piece configured to be inserted into the secondary recess to prevent the member from withdrawing from the elongate recess, and locking means to hold the locking piece in place.

[0025] Preferably, the secondary recess extends into a further axial recess, configured to receive the clamp, so that the first module piece may be moved axially relative to the member, until the clamp enters the further axial recess, before inserting the locking piece. [0026] Preferably, the further axial recess is of a size and shape to prevent substantial radial movement of the clamp once received.

[0027] Preferably, the first module piece is substantially cylindrical, having an axis substantially coincident with the axis of the member once received.

[0028] Preferably, the elongate recess comprises a radius portion configured to receive a cylindrical member.

[0029] Preferably, the elongate recess is of a wider section toward each opposed end of the first module piece than at a centre, so that the elongate recess is configured to receive a curved member.

[0030] Preferably, the locking piece is configured to hold the clamp in place and prevent withdrawal of the clamp from the first module piece.

[0031] Preferably the locking piece extends at least partially along the length of the elongate recess.

[0032] Preferably the locking means comprises a click-fit feature, configured to engage once the locking piece is inserted to a sufficient extent.

[0033] Preferably the locking means comprises a strap around the first module piece and the locking piece.

[0034] Alternatively, the locking means comprises a pin inserted through a portion of the first module piece into the locking piece.

[0035] Alternatively, the locking means comprises a plurality of biased pins, wherein the pins are biased to engage with corresponding recesses once the locking piece is inserted to a sufficient extent. BRIEF DESCRIPTION OF DRAWINGS

[0036] The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

[0037] Figure 1 is an isometric view of a section of a member comprising a clamp as is known in the art, with no buoyancy module attached.

[0038] Figure 2 is an isometric view of a first module piece according to an embodiment of the present invention, the first module piece being located in position around a member and clamp with the clamp positioned in the secondary recess.

[0039] Figure 3 is an isometric view of a first module piece according to an embodiment of the present invention, the first module piece being located in position around a member and clamp with the clamp positioned in the further axial recess.

[0040] Figure 4 is an isometric view of a first module piece and locking piece according to an embodiment of the present invention, the first module piece being located in position around a member and clamp and the locking piece being located in the elongate and secondary recesses.

[0041] Figure 5 is an isometric view of a buoyancy module according to an embodiment of the present invention, the locking means being a single strap.

[0042] Figure 6 is an isometric view of a buoyancy module according to an embodiment of the present invention, the locking means being two straps.

[0043] Figure 7 is an isometric view of a buoyancy module according to an embodiment of the present invention, the locking means being locking pins.

[0044] Figure 8 is an isometric view of a buoyancy module according to an embodiment of the present invention, the locking means being sprung locking pins.

[0045] Figure 9 is an isometric view of a buoyancy module according to an embodiment of the present invention, the buoyancy module being located in an assembly apparatus in the open position. [0046] Figure 10 is an isometric view of a buoyancy module according to an embodiment of the present invention, the buoyancy module being located in an assembly apparatus in the closed position.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0047] Referring to the Figures, there is shown a buoyancy module 10 for installing on a member, the member having an axis and a clamp, and the buoyancy module 10 comprising a first module piece 20 comprising a elongate recess 22 configured to receive the member along its axis, and a secondary recess 24 configured to receive the clamp, a locking piece 30 configured to be inserted into the secondary recess 24 and prevent the member from withdrawing from the elongate recess 22, and locking means 32 to hold the locking piece 30 in place.

[0048] The secondary recess 24 may extend into a further axial recess 26, configured to receive the clamp, so that the first module piece 20 may be moved axially relative to the member, until the clamp enters the further axial recess 26, before inserting the locking piece 30.

[0049] In a preferred embodiment of the present invention, the first module piece 20 may be substantially cylindrical, with the elongate recess 22 extending along the length of the first module piece 20 in the axial direction, and from an inner radius having a centre substantially coincident with the axis of the member, to the outer surface of the first module piece 20, in the radial direction.

[0050] The elongate recess 22 may comprise a radius portion, so that a cylindrical member may be received.

[0051] Alternatively, the elongate recess 22 may be of a wider section toward each end of the first module piece than at the centre, to accommodate a curved member. [0052] The secondary recess 24 may comprise a widened portion of the elongate recess 22, wherein the width is sufficient to accommodate the clamp attached to the member.

[0053] The further axial recess 26 may be of a size and shape to accommodate the clamp so that the member having the clamp may be moved along its axis, and the clamp element enters the further axial recess 26.

[0054] The further axial recess 26 may be of a size and shape to prevent substantial radial movement of the clamp once received.

[0055] The further axial recess 26 may be slightly larger in diameter than the clamp.

[0056] The locking piece 30 may be configured to hold the clamp in place and prevent the clamp from withdrawing from the first module piece 20.

[0057] The locking piece 30 may be sized to substantially fill the void of the secondary recess.

[0058] Alternatively, the locking piece 30 may be sized to extend at least partially along the length of the elongate recess 22.

[0059] The locking piece 30 may be sized to substantially fill the void of both the secondary recess 24 and the elongate recess 22 once the member is installed, so that buoyancy of the buoyancy module 10 is substantially even around the axis of the member.

[0060] Alternatively, where less or additional buoyancy is required, the locking piece 30 may be sized to meet this requirement.

[0061] The locking piece 30 may comprise locking features 32 to prevent the locking piece 30 from withdrawing from the first module piece 20 during operation.

[0062] The locking features 32 may comprise a click-fit.

[0063] The locking features 32 may comprise at least one strap around the assembly comprising the first module piece 20 and the locking piece 30. [0064] The locking features 32 may comprise at least one pin inserted through a portion of the first module piece 20 into the locking piece 30.

[0065] The locking features 32 may comprise biased pins, wherein the pins are configured to be forced out against the bias, and sprung into the biased position once recesses in the locking piece 30 are aligned with the pins.

[0066] The buoyancy module 10 may be fitted using an assembly apparatus 40, the apparatus 40 supporting a first module piece support 42 and a locking piece support 44.

[0067] The first module piece 20 and locking piece 30 comprise engagement features, wherein the engagement features are configured to be affixed to the assembly apparatus 40, so that the first module piece 20 and locking piece 30 are held in position relative to one another, wherein the assembly apparatus 40 is configured to enable relative movement of the locking piece 30 and the first module piece 20.

[0068] The assembly apparatus 40 may comprise a beam configured to allow linear movement of the first module piece support 42 and the locking piece support 44 relative to one another.

[0069] In use, the crew are positioned in the known manner, with the member having the clamp affixed being fed toward the crew.

[0070] The first module piece 20 may be suspended and moved using standard lifting equipment such as winches, hoist and guy lines.

[0071] The member having the clamp affixed is passed into the elongate recess 22, with the clamp passing into the secondary recess 24.

[0072] In a preferred embodiment of the present invention, where the first module piece 20 comprises a further axial recess 26, once the axis of the member having the clamp is aligned with the axis of the first module piece 20, the member can be slightly retracted, or the first module piece 20 lowered, causing the clamp to enter the further axials recess 26. [0073] Once the clamp is located in the further axial recess 26, significant movement in a radial direction is prevented due to the close fit of the clamp in the further axial recess 26.

[0074] Movement in one axial direction is also prevented as the clamp cannot pass along the elongate recess 22 beyond the extent of the further axial recess 26.

[0075] Once the clamp is located in the further axial recess 26, the first module piece 20 is additionally supported by the member itself.

[0076] The prevention of movement as described herein provides a much safer working environment, as the large mass of the first module piece 20, is supported by the member and clamp, in addition to any hoists and guy lines required.

[0077] Furthermore, the use of the single piece, being the first module piece 20, as opposed to two pieces, being halves of a buoyancy module as is known in the art, provides a much safer working environment. This is in part due to fewer heavy items being suspended in the working area, and in part due to the removal of the risk of pinch injuries or other similar injuries resulting from the two halves of a known buoyancy module colliding during the operation.

[0078] Once the first module piece 20 is in position and suitably restrained, the locking piece 30 can be inserted into the secondary recess 24, thus preventing the clamp and member from withdrawing and coming free of the buoyancy module 10.

[0079] In an alternative embodiment of the present invention, which does not comprise the further axial recess 26, the locking piece 30 may simply prevent the clamp from withdrawing from the first module piece 20 through the secondary recess 22

[0080] The locking piece 30 may be fixed in place using locking features 32.

[0081] Once the locking piece 30 is fixed in place using the locking features 32, the member may be advanced, submerging the buoyancy module 10 and providing the subsequent portion of the member to the crew, ready for installation of another buoyancy module 10. [0082] Where the assembly apparatus 40 is used, the first module piece 20 is affixed to the first module piece support 42, and the locking piece 30 is affixed to the locking piece support 44.

[0083] The member and clamp are located between the first module piece 20 and the locking piece 30, and the two pieces 20 and 30 are closed around the member and clamp.

[0084] The use of the assembly apparatus 40 prevents unwanted relative movement between the first module piece 20 and the locking piece 30, by permitting only linear relative movement.

[0085] The use of a single first module piece 20 comprising the majority of the mass in a single piece rather than two pieces, allows for a safer working environment, requires fewer crew members and provides a quicker installation.

[0086] Known buoyancy modules require sufficient crew members to secure the two large suspended loads, being the two halves of the module, whereas a single large suspended load can be secured by fewer crew members.

[0087] The installation process involving passing the member and clamp into the elongate recess 22 and secondary recess 24 can be achieved either more quickly, more safely, or with fewer crew members than the known process of positioning the member and clamp in between the two suspended loads.

[0088] The process of inserting the locking piece 30 can be achieved more quickly, more safely and with fewer crew members than the known process of affixing mechanical straps around the two suspended loads.

[0089] The entire process of installing the buoyancy module according to the present invention 10 can be achieved more quickly, more safely and with fewer crew members than the known method of installing buoyancy modules comprising two halves. [0090] Where the assembly apparatus 40 is used, the risk of injury is further reduced by the prevention of unwanted movement between the first module piece 20 and the locking piece 30.

[0091] The time taken to install a buoyancy module 10 using the assembly apparatus 40 may be further reduced, in part by assisting with the locating of the locking piece 30 into the first module piece 20, and further by allowing the first module piece 20 and locking piece 30 to be affixed to the first module piece support 42 and the locking piece support 44, prior to the member and clamp being received by the crew.

[0092] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.