GB2355425A - Internal pipeline clamp - Google Patents

Abstract

A support apparatus 1 for use in welding pipe sections 40,50 comprises a modular unit adapted to provide a circumferential support surface 28. Preferably, the apparatus is in the form of a modular internal pipeline clamp 1, which provides a fusion resistant backing strap 28 to support a weld pool when welding circumferential joints from the outside of the pipeline. A central body 2 preferably provides a host facility for interchangeable or modular components that can be fitted to vary the operating diameter of the clamp so that it can be accommodated in pipelines of various diameters. The backing strap 28 is preferably connected to a plurality of extension plates 12 which are moved relative to the pipeline interior surface by hydraulic rams 10. The clamp can also be used to align the pipe sections 40,50 to be welded.

Description

1 2355425 1 "Support Apparatus and Method" 2 3 The present invention

relates to a support apparatus 4 and method and in particular to a support apparatus 5 mountable within a pipe to provide a welding surface, 6 and to a method of facilitating the welding of a pipe. 7 8 When fabricating a pipeline by welding sections of pipe 9 together, in order to achieve and to maintain an 10 acceptable internal profile for the pipeline, it is 11 important to provide support for the weld bead from the 12 inside of the pipe when welding each junction. 13 14 It is also necessary-to produce a weld without defects. 15 It is thus important that abutting ends of pipe 16 sections to be welded together are aligned correctly, 17 since poorly aligned pipe ends will invariably provide 18 defective welds. 19 2 1 To date, the requirements firstly to align pipe ends 2 accurately, and secondly to support weld bead have been 3 addressed as if inseparable. 4 5 The usual method of welding a pipeline is to align the 6 pipe sections by clamping them together. 7 8 This is done either by utilising internal clamps 9 inserted within the pipes, or external clamps placed 10 over the junction between pipe sections (the If it up,) 11 and fastened to hold the pipe sections together prior 12 to welding. 13 14 A pipeline is manufactured by the sequential addition 15 of pipe sections to form a progressively lengthening 16 structure. The technique of choice for fabricating 17 pipes of long length, such as pipelines, is mechanised 18 high productivity welding. This technique utilises a 19 mechanical welding head mounted on a guide ring adapted 20 to fit round and to move along the pipe. The guide 21 ring requires a clear path across each weld fit up. 22 Fitting a clamp on the outside of the pipe would 23 obstruct this path. External clamps are thus only of 24 use in manual welding. 25 26 Pipes are sized by their external diameter. The 27 internal diameter of a pipe is therefore dependent on 28 wall thickness and will vary. To weld pipes of varying 29 internal diameters requires mechanised welding. 30 31 Known internal clamps can be used to weld lengths of 32 steel pipe to form a pipeline. Known internal clamps 3 1 have two functions namely, to hold two ends of pipe 2 concentric and in the correct relative axial positions 3 during welding; and to provide support for the weld 4 bead in the inside of the pipe. Internal clamps are 5 diameter or pipe bore specific. If the wall thickness, 6 and thus the internal diameter of a pipe, varies along 7 its length, a selection of clamps is required. 8 Similarly, to fabricate pipes of different diameter, 9 specific clamps are required for each. 10 11 Known pipeline internal clamps cost a minimum of $50k 12 each and, due to the nature of the business of pipeline 13 fabrication, a redundant clamp of each size is always 14 required since commercial pressures do not allow time 15 for repairs. The cost of tooling up for the range of 16 diameters of pipeline likely to be welded by any 17 pipeline manufacturing business is therefore 18 significant. Such pipe clamps are normally hired at 19 considerable expense. 20 21 It is an object of the present invention to address the 22 requirement to align the sections of a pipe to be 23 welded, and the requirement to support the integrity of 24 the pipe during welding. This invention realises the 25 need to distinguish these requirements. 26 27 According to a first aspect of the present invention 28 there is provided a support apparatus for use in 29 welding pipe sections comprising a modular unit adapted 30 to provide a circumferential surface. 31 4 Said support apparatus may provide circumferential surfaces of various sizes. 3 4 Preferably said support apparatus comprises a central 5 body member and extension members having removable and 6 replaceable elements. 7 8 Preferably said extension members comprise a ram or 9 rams. Said extension members may comprise support 10 means. Said support means preferably describes the 11 circumferential surface of the apparatus. 12 13 Preferably said support means comprises a system of 14 plate members configured for relative movement. 15 16 Said support means is preferably adaptable to provide 17 support to a weld seam at a junction between pipe 18 sections. 19 20 Preferably said apparatus comprises a single power 21 distribution source. Said apparatus may be 22 hydraulically powered. Said apparatus may be 23 pneumatically powered. Typically said apparatus 24 comprises power delivery means. 25 26 Preferably said apparatus is adapted to deliver 27 pressure only to the weld seam of the pipe and to no 28 other area. 29 30 Further according to the present invention there is 31 provided a mechanised line up bed comprising static 32 pipe holding and manoeuvring means; new pipe feed and 1 manoeuvring means; and means for manoeuvring the back 2 end of new pipe.

3 4 Further according to the present invention there is provided an internal pipe clamp system adapted to 6 support a weld bead. Preferably said internal pipe 7 clamp system has no alignment function. Preferably said 8 internal pipe clamp system is adapted for use in 9 conjunction with external pipe alignment means.

11 According to a further aspect of the present invention 12 there is provided a method for facilitating welding of 13 a joint between two sections of pipeline comprising the 14 steps of:

identifying the internal diameter of the pipeline; 16 fitting appropriately sized extension members to a body 17 member to create a support apparatus; 18 positioning said support apparatus in the pipeline 19 beneath the joint to be welded; supplying power to the support apparatus; and 21 forming the circumference of the support apparatus 22 tight against the joint.

23 24 Preferably said method further includes the step of aligning said sections using a mechanised test bed.

26 27 Embodiments of the present invention will now be 28 described by way of example only with reference to the 29 accompanying drawings in which:

31 Fig 1 is a schematic view of the support apparatus 32 of the present invention; 6 2 Fig 2 is a cross-section view along Section A-A' 3 of Fig 1; and 4 5 Fig 3 is a detail of Fig 1, illustrating the 6 lateral support configuration and the relative 7 positions of the elements of the circumferential 8 surface of the support apparatus when the 9 apparatus is de-energised. 10 11 High productivity welding of two pipe sections is 12 started by putting a bead or root run in the centre of 13 the joint of the abutting surfaces of the sections.

14 Welding is started at the top of the pipe and finished at the bottom. To maintain the integrity of the 16 internal diameter of the pipe during welding it is 17 necessary to support the joint from within the pipe.

18 19 That is, to maintain an acceptable internal profile of the pipeline the weld bead re i quires support from the 21 inside of the pipe.

22 23 The present invention provides an apparatus the outer 24 circumferential surface of which can be energised to form a fusion resistant strap of length equal to the 26 internal circumference of the pipe being welded. This 27 strap ensures uniform support around the full 28 circumference of the weld.

29 Referring to the drawings, a support apparatus 1 31 comprises a body member 2, a plurality of extension 7 1 members and a system of support members configured to 2 provide a support surface of variable size around the 3 the outer circumference of the support apparatus 1.

4 The apparatus I is of modular construction and, in use, provides internal support to a joint 3 between two 6 sections of a pipe 40, 50.

7 8 The modular nature of the construction of the support 9 apparatus 1 enables its adaptation for use in welding pipes of different wall thicknesses and diameters.

11 This adaptation is possible because individual 12 components of the apparatus 1 are removable and 13 replaceable and, to adapt the apparatus for a 14 particular requirement, a user need merely remove individual or multiple components and fit appropriate 16 replacements parts sized to suit. The modular nature 17 of the support apparatus 1 therefore facilitates its 18 use over a significant range of diameters and wall 19 thicknesses of pipes.

21 The body member 2 is a cylindrical machined bar. The 22 body member 2 is adapted to distribute power, and 23 includes power delivery means. The basic power delivery 24 means is centrally located in the apparatus 1, which facilitates segmental increase of the diameter of the 26 apparatus 1.

27 28 Specifically, the body member 2 is adapted to house, at 29 its core, a master cylinder in the form of a central hydraulic gallery 31. The body member 2 further 31 comprises a series of canals 6 in the form of radial 32 hydraulic galleries that radiate outwardly from the 8 1 central gallery 31. These canals 6 are dedicated to the 2 delivery of power from the body member 2 to the 3 extension members. 4 5 Associated with each canal 6 is a radial chamber 8. 6 The body member 2 is machined to accommodate the 7 plurality of radial chambers 8. The radial chambers 8 8 are situated in pairs in regular array around the 9 circumference of the base member 2, with alternate 10 pairs of chambers 8 displaced axially. The canals 6 11 connect the central gallery 31 to the radial chambers 12 8. 13 14 Each extension member comprises a pair of double acting 15 powered rams 10 and an extension plate 12. Each ram 10 16 is housed in a separate radial chamber 8. The rams 10 17 are precision fit in the chambers S. The rams 10 are 18 hydraulically powered. The rams 10 are supplied with 19 hydraulic oil via the central hydraulic gallery 31. 20 21 Each ram 10 is adapted for attachment of an extension 22 plate 12. The extension plate 12 is of IT' section, 23 the vertical leg providing axial location. Each 24 extension plate 12 attaches to a single pair of rams 25 10. That is, the chambers 8 are sited to accommodate 26 two rams 10 per extension plate 12, with adjacent pairs 27 of rams 10 staggered axially. An additional benefit of 28 the configuration of two rams 10 per plate 12 is that 29 it keeps the ram bore to a minimum. 30 31 The extension plate 12 is removable and replaceable. 32 Thus the appropriate size of extension plate 12 can be 9 1 attached to the rams 10 to customise the apparatus for 2 the particular pipe to be welded.

3 4 A bridging bar 11 is pinned to the external extremities 5 of each pair of rams 10 by means of screw connections.

6 The extension plate 12 is adapted for secure fitment to 7 the rams 10 through the bridging bar 11.

8 9 The support apparatus 1 comprises a substantial number 10 of sets of extension plates 12 of a variety of useful 11 sizes. Each set comprises a number of identical 12 extension plates 12 machined to dimensions appropriate 13 to a specific internal pipe diameter. The appropriate 14 extension plates 12 can be attached as necessary.

is 16 For larger internal diameters, structural support for 17 each extension plate 12 is provided by a roller 18 assembly comprising rollers 17, roller support members 19 16 and a circular end collar 18.

21 The collar 18 comprises two discs clamped near the ends 22 of the body member 2. These discs support the 23 transverse roller support members in the form of 24 shouldered rods 16. The roller support members 16 are 25 adapted to carry the rollers 17. The rollers support 26 the extension plates 12. One roller assembly is 27 required for intermediate nominal bore pipes. Pipes of 28 larger nominal bore require a further larger collar 18. 29 The circumferential surface of the support apparatus 1 31 is described by a system of support members in the form 32 of a plurality of plates 26,27 which co-operate to I provide a circumferential strap 28 of length equal to 2 the internal circumference of the pipe being welded.

3 The strap 28 is of uniform width around the full 4 circumference of the weld to ensure uniform support.

The plates 26,27 are either made substantially from, or 6 coated with a fusion resistant material, such as 7 copper.

8 9 Each extension plate 12 is adapted for fitment, at its external extremity, of housing means for the attachment 11 of the plates 26,27. The housing means comprises a 12 dovetail slide 20. The slide 20 is attachable to the 13 extension plate 12 by screwed connection 22. The 14 housing means further comprises a holder 24 associated with each slide 20. The holder 24 is adapted for the 16 attachment of the plates 26,27, and adapted for smooth 17 movement along the slides 20. The slides 20 and the 18 shoe holders 24 are precision machined to enable smooth 19 movement therebetween.

21 In this embodiment, the holder is a shoe holder 24 and 22 the plates are copper shoes 26,27. Adjacent shoes 23 26,27 are adapted for relative movement. In this 24 described embodiment, each alternate shoe 26 is fixed axially in the dovetail slide 20, and its two 26 neighbouring shoes 27 are adapted to move.

27 28 The copper shoes 26,27 are precision machined in 29 circumferential segments. Various embodiments of the support apparatus 1 have a circumferential surface 31 comprised of between four and twelve shoes 26,27. The 32 shoes 26,27 are angular in shape to enable expansion of 11 1 the circumferential surface. This allows the support 2 apparatus to deliver a surface area of backing strap 28 3 appropriate to the internal diameter of the pipe being 4 welded. 5 6 The moveable copper shoes 27 are spring loaded against 7 the fixed copper shoes 26 by springs 25. The end faces 8 of the copper shoes 26,27 are chamfered such that as 9 the fixed shoes 26,and spring loaded shoes 27 are moved 10 radially, the spring loaded shoes 27 move axially, 11 automatically maintaining contact between neighbouring 12 segments at all times. 13 14 The support apparatus 1 comprises a substantial number 15 of sets of slides 20, holders 24 and shoes 26,27 of a 16 variety of useful sizes. There is thus available a 17 selection of slides 20, holders 24 and shoes 26,27 18 machined to dimensions appropriate for fitment to the 19 extension plates 12 to provide a circumferential 20 surface of any dimensions required. 21 22 In use, hydraulic power is provided via the body member 23 2 to energise the coupled rams 10 and extension plates 24 12. When the rams 10 and extension plates 12 are 25 energised, the shoe holders 24 and associated shoes 26, 26 27 are moved radially in the slides to expand the 27 diameter of the support apparatus 1 and to form a 28 circumferential surface which makes firm contact with 29 the internal circumference of the pipe wall, just under 30 the weld joint. 31 12 1 That is, the support apparatus is firstly configured to 2 suit the pipeline being welded, positioned within the 3 pipe, and then energised prior to welding with the 4 result that its outer circumferential surface provides 5 a fusion resistant strap 28 which fits tight against 6 the pipe. 7 8 When welding is complete and weld support is no Longer 9 required the clamp is de-energised, and the shoe 10 holders 24 and associated shoes 26,27 are moved in the 11 slides 20 to contract the diameter of the support 12 apparatus 1 for extraction. 13 14 If the support apparatus 1 is required for use in a 15 pipe of different internal diameter or wall thickness, 16 the apparatus can be reconfigured accordingly. 17 The slides 20, holders 24, shoes 26,27 and/or extension 18 plates 12 are replaced to provide a support apparatus 19 of suitable configuration. 20 21 The modular nature of this support apparatus 1 allows a 22 single base member 2 to be adapted for use as a power 23 source and delivery mechanism for use in welding a 24 large variety of geometrical configurations of pipe. 25 26 In this embodiment, movement of the alternate shoes 27 27 around their angles is a feature of their geometrical 28 design and configuration. 29 30 Each copper shoe 26,27 is precision machined to 31 specific dimensions. The copper shoes 26,27 are 32 precision machined to ensure that there are no gaps or 13 1 misalignments between them, or any uneven level in any 2 plane. Neighbouring shoes 26,27 are shaped as opposing 3 trapeziums. Fig 3 shows the relative axial positions 4 of the shoes 26,27 of this embodiment when the 5 apparatus is de-energised, the arrows showing the 6 direction of movement of the shoes 27. 7 8 In this embodiment the shoes 26, 27 are energised in 9 such a way as to enable expansion of the support 10 apparatus 1 to occur without loss of integrity in the 11 seams between the shoes 26,27. 12 13 When the apparatus 1 is energised, the geometric 14 integration of the individual copper shoes 26,27 as a 15 combined result of radial movement delivered by the 16 combined rams 10 and extension plates 12, and axial 17 movement of the shoes 27 by the springs 25, produces a 18 fusion resistant backing strap 28 circumferentially 19 compatible with the inside of the pipe. Integration of 20 the copper shoes 26,27 establishes the backing strap 28 21 for the weld seam. 22 23 The body member 2 contains drillings for annular 24 galleries 31, 32, 33. The annular galleries 31,32 25 supply hydraulic oil to the full bore and annulus side 26 of the rams 10 in the chambers 8, and the annular 27 gallery 33 carries any leakage from the rams 10 back to 28 a drain connection 34. The full bore side of the rams 29 10 is supplied with hydraulic oil via the central 30 hydraulic gallery 31. 31 14 1 Cylinder end caps 42, screwed into the body member 2, 2 each contain two seals. The purpose of the seals is to 3 prevent contamination of the coppers by hydraulic oil. 4 Drillings between the seals allow any leakage of 5 hydraulic oil to be fed back to the power unit through 6 an umbilical tube 35. 7 8 A distributor plate 36 is bolted at one end of the body 9 member 2. This distributor place contains the three 10 annular galleries 31,32,33 that collect and/or 11 distribute oil to and/or from the annular side of the 12 cylinders and collect oil from the drain lines. Three 13 seals are provided to separate the supply line, return 14 line, and drain line.

is 16 The support apparatus 1 is adapted for fitment to a 17 transport bogey 37 to enable its rapid deployment in a 18 pipeline. The bogey 37 is a simple structure, specific 19 for a particular pipe diameter, which runs on sprung wheels. These wheels contact the inside of the pipe to 21 permit delivery of the support apparatus 1 to its 22 required destination, whilst avoiding contact between 23 the support apparatus 1 and the inside wall of the 24 pipe.

26 A hollow rod 38 sized to the requisite length is 27 attached at a first end to the body member 2 or to the 28 transport bogey 34. The rod allows accurate 29 positioning of the support apparatus 1 by an operator.

In addition, the rod acts as a conduit for hydraulic 31 fluid to the body member 2 from a free standing 32 hydraulic power unit.

1 In an alternative embodiment the apparatus 1 is adapted 2 to be powered pneumatically, and the power delivery 3 means is adapted accordingly. 4 5 The control means for the support apparatus 1 is 6 situated at a second end of the rod. The control means 7 allow an operator to regulate delivery of power to the 8 apparatus 1 and thus to energise or de- energise the 9 support apparatus 1 as required. 10 11 When a pipeline requires welding, and prior to using 12 the support apparatus I of the instant invention, an 13 operator first determines the internal diameter of the 14 pipeline to be welded, and calculates the size of 15 extension plates 12 as required. 16 17 once the size required is selected, identical extension 18 plates 12 are affixed to each primary ram 10. A 19 dovetail slide 20 is then affixed to each extension 20 plate 12. The individual copper shoes 26 are then 21 affixed to the shoe holders 24, and the combination of 22 shoe holder 24 and shoe 26,27 then secured to the 23 dovetail slide 20. 24 25 The basic unit of the support apparatus 1, namely the 26 base member 2 and the primary rams 10 is adaptable for 27 use in pipelines of various internal diameters. That 28 is, when a new pipeline is to be welded, the operator 29 fits a set of appropriate extension plates 12 of 30 required size from the selection of extension plates 31 12. 32 16 1 To obtain a backing strap of appropriate circumference 2 it is necessary to fit appropriately sized dovetail 3 slides 20, shoe holders 24 and shoes 26,27 from a 4 selection of sets of slides 20, shoe holders 24 and s shoes 26,27 that comprise the apparatus. 6 7 To subsequently weld a pipeline of different internal 8 diameter, all that may be required is to adjust the 9 expansion capability of the copper shoe arrangement. 10 11 Alternatively it is possible to replace the extension 12 plates 12 and/or the slides 20, holders 24 and shoes 13 26,27 from a selection provided with the modular body 14 member 2, to create a suitably sized support apparatus 16 17 once a suitably sized support apparatus 1 is quickly 18 assembled, it is fixed to a transport bogey 37 19 appropriate to the pipeline diameter. The apparatus 1 20 is adapted to travel along a pipe on wheeled frames or 21 bogies 37 situated at each end. Clearance is required 22 for the wheels, and for the copper shoes 26, 27 23 situated inside the line of the wheels. The rams 10 24 thus have a required minimum stroke of the sum of the 25 two clearances, plus an allowance for tolerances in 26 each pipe. 27 28 The rod 38 is attached to the assembled support 29 apparatus 1. 30 31 When two pipe sections are suitably aligned, the 32 support apparatus 1 is inserted within the pipe.

17 1 Because clearance is required between the wheeled 2 frames 37 and the pipe, the unit 1 always starts 3 eccentric to a pipe. This means that it is difficult 4 to provide a mechanical linkage that gives a fixed 5 relationship between the radial and axial movement of 6 the copper shoes 26, 27. This is one reason why 7 alternate copper segments 27 are spring loaded. 8 9 The rod 38 and the bogey 37 are used to position the 10 apparatus 1 at the joint 3 between the two pipes 11 requiring to be welded, directly under the weld seam. 12 13 The support apparatus 1 is inserted in static state. 14 once in position, power is supplied to the apparatus 1 15 to energise the apparatus 1. The combined rams 10 and 16 extension plates 12 extend radially from a first, 17 retracted position to a second, extended position, and 18 expand the circumference of the strap 28 by moving the 19 shoes 27. This provides a backing strap 20 circumferentially compatible with the internal 21 circumference of the seam prior to, and during the 22 welding process. That is, the support apparatus 1 is 23 energised to expand against the weld joint to provide a 24 tight fit. 25 26 The support apparatus 1 is energised by controlled 27 delivery of hydraulic fluid from a free standing 28 hydraulic power unit to the body member 2 to pressurise 29 the hydraulic gallery 31. Delivery of the fluid is 30 controlled by an operator using the control means 31 situated at the second end of the rod 38. The gallery 32 31 feeds hydraulic power to the radial cylinders 8 via 18 1 the canals 6. The hydraulic pressure supplied to the 2 powered rams 10 and their selected associated extension 3 plate 12 causes the combined rams 10 and extension 4 plates 12 to extend radially. 5 6 The geometric integration of the copper shoes produces 7 a fusion resistant backing strap 28 circumferentially 8 compatible with the inside of the pipe being welded, 9 and without any gaps, misalignments or unevenness. 10 This backing strap 28 supports the first root or bead 11 run of a welding process conducted on the outside of 12 the pipes, both during the execution of the weld and 13 during the post weld cooling process. 14 15 In a further embodiment of the apparatus 1 each shoe 16 holder 24 comprises an angular slot in which a floating 17 peg is configured to move. Again, integration of the 18 plurality of copper shoes 26,27 establishes the backing 19 strap 28 for the weld seam. 20 21 More specifically, outward movement of the combined 22 rams 10 and extension plates 12 generates horizontal 23 movement relative to the rams 10 and extension plates 24 12 of each dovetail slide 20 and its associated shoe 25 holder 24. This horizontal movement is generated by a 26 peg-in-slot facility in the extremities of the holders 27 24. That is, each shoe holder 24 has an angular slot 28 at at least one end, configured to accommodate a 29 floating peg. Movement of the combined rams 10 and 30 extension plates 12 causes the floating peg to ride up 31 in the slot. This peg acts to move the shoe holder 24. 32 19 1 These embodiments of the invention enable the welding 2 of carbon steels or other materials that do not require 3 oxygen purging. 4 5 In a further embodiment the support apparatus 1 6 optionally comprises oxygen purging, containment and 7 measuring means. These means enable the welding of 8 corrosion resistant alloys to take place, supported by 9 an environment inside the pipe filled with a purging 10 gas. The purging gas is preferably argon. 11 12 Attached to either side of the basic support apparatus 13 1 are barrier means, which form a closed environmental 14 barrier around the support apparatus 1, for purging 15 containment. The support apparatus 1 operates within 16 the barrier. 17 18 In this embodiment the barrier means are energised by 19 purge gas. In this embodiment the barrier means are 20 expandable bladders 30 which, when energised, expand to 21 create, in co-operation with the pipe wall, a closed 22 containment chamber around the support apparatus 1, 23 which can be filled with purging gas. 24 25 In an alternative embodiment the barrier means are 26 fixed. In this embodiment the barrier means are 27 circular plates machined to a size proportional to the 28 internal diameter of a pipe allowing sufficient 29 clearance to accommodate a neoprene layer between a 30 plate and the internal surface of the pipe, and fixed 31 securely to the base member 2. The neoprene layer 32 enables the barrier to move within the pipe.

2 In either embodiment the barrier means allow oxygen to 3 be "chased" from the chamber through an escape hole 39 4 to the pipe annulus. 5 This embodiment of the support apparatus 1 is adapted 6 to accept a hose connection 29 and associated hose 41. 7 When welding corrosion resistant alloys, a purging gas 8 is fed from an outside source to the apparatus 1 9 through the hose 41. The gas source comprises valves 10 to regulate the flow of purging gas. When the purging 11 gas is released inside the containment chamber this gas 12 displaces the oxygen from the.environment prior to 13 welding. 14 15 An accurate sensor adapted to measure the gas/oxygen 16 ratio is fitted to the support apparatus 1, or 17 externally to the exhaust. The sensor continuously 18 monitors this ratio, and relays the data via an 19 electric or digital cable to a display located at a 20 suitable viewing station. When the reading reaches the 21 appropriate level, welding can commence. The 22 gas/oxygen ratio is monitored continuously throughout 23 the welding process in order that it may be kept at the 24 appropriate level. 25 26 The purging means may be provided as an optional 27 attachment to a basic support apparatus 1. 28 29 When welding is suitably advanced to allow the removal 30 of the support apparatus, the apparatus is de31 energised, reversing the expansion of the rams 10 and 32 extension plates 12. The rams 10 are double acting, 21 1 enabling powered de-energising which returns the rams 2 10 and extension plates 12 and their associated shoes 3 26, 27 to their first, retracted position. 4 5 This support apparatus 1 does have the facility of 6 aligning the pipe ends to ensure that each end of the 7 pipes being welded is vertical. The pipes are aligned 8 independently of the support apparatus 1. 9 10 Instead, the support apparatus 1 is dedicated to 11 delivery of an internal backing strap to the weld. 12 This ensures that the sole result of energising the 13 support apparatus is to form the backing strap 28 14 securely to the internal pipe surface. 15 16 Since the alignment facility is provided separately, 17 the support apparatus 1 is only energised at one is location. The support apparatus 1 thus provides a19 welding surface that gives uniform support around the 20 weld seam. The tight-fitting welding surface of fusion 21 resistant material allows the weld pool to be firstly 22 in molten condition, and then to cool to solid state, 23 without deformation. 24 25 When cylindrical pipelines are aligned, they tend to be 26 deformed to become oval. A further advantage of the 27 support apparatus 1 of the present invention is that it 28 acts to improve the geometry of the alignment of the 29 pipe ends. Since the only area of the aligned pipes to 30 receive internal pressure is the weld seam, the 31 apparatus acts to remove ovalness from the weld joint 32 'fit-up'. That is, providing power (either hydraulic 22 or pneumatic) to the support apparatus enables the 2 removal of some degree of ovalness from the pipe ends.

3 4 This invention further provides means for alignment of S pipe sections comprising a mechanised line up bed.

6 7 The bed comprises three main operating components 8 namely, static pipe holding and manoeuvring means; new 9 pipe feed and manoeuvring means; and means for manoeuvring the back end of new pipe.

11 12 In use, the fit up of pipe sections takes place between 13 the static pipe holding and manoeuvring means and the 14 new pipe feed and manoeuvring means. The means for manoeuvring the back end of new pipe is able to be 16 split from the other components for a distance of up to 17 36m to enable feeding of varying lengths of sections of 18 new pipe.

19 In the line up bed, pipes are welded together to form 21 an increasing length of stalk which may be upwards of 22 1km in length and comprise 80 or more joints.

23 24 In use, the mechanised line up bed remains static and 2S once a joint is welded, the pipe stalk is pulled 26 through the bed for a distance equal to the length of 27 the new pipe section. The tail end of the stalk is 28 then halted in the mechanised line up bed.

29 A further section is then inserted in the mechanised 31 line up bed and the bed's facility becomes operative.

32 The mechanised line up bed is configured to hold the 23 1 end of the already fabricated stalk securely, and to 2 manipulate the stalk both horizontally and vertically, 3 and from left to right, within a given range. 4 The line up bed is configured to then feed the new 5 section of pipe towards the stalk end. This is done by 6 placing the new section on powered rollers. The 7 horizontal drive of the bed then moves the pipe 8 horizontally until the machined end of the new pipe 9 section abuts the machined end of the existing stalk. 10 The bed is configured to perform the initial stage of 11 this step at reasonable pace until the ends are in 12 clcse proximity, when the step is completed in very 13 small measures, for example in steps of 0.5mm 14 horizontal movement. 15 16 The bed is further configured to manipulate the pipe 17 section horizontally, vertically, left and right in 18 very small increments when holding the pipe section 19 securely in close proximity to the stalk. These final 20 adjustments give upwards of 0.22mm accuracy when final 21 fit is in progress.

22 23 The bed is further configured to enable the pipe to be 24 rotated on its axis both clockwise and counterclockwise whilst maintaining its horizontal plane, when the pipe 26 ends are in close proximity. This allows an operative 27 of the mechanised line up bed operative to make a 28 visual judgement on the fit up condition.

29 The bed is further configured to manoeuvre the trailing 31 end of the new pipe section joining the pipe stalk 32 horizontally, vertically, left and right.

24 2 When the ends are aligned and fit up is complete, the 3 horizontal drive of the bed is used to maintain a soft 4 pressure on the pipe section. This urges the new pipe 5 section towards the stalk end during welding, which 6 ensures maintenance of a tight fit of the machined 7 ends. 8 9 The bed is further configured to reverse the new pipe 10 section away from the stalk end if required. 11 12 All of the above functions of the mechanised line up 13 bed for handling of the static pipe end of the pipe 14 stalk, and new pipe section alignment are controllable 15 by means of a single hand held control unit (pendants) 16 connected to the bed. The bed is thus operable through 17 an umbilical. This enables operation of alignment by 18 the operative via the hand held control whilst 19 conducting close visual inspection of the fit up. 20 21 The support apparatus 1 is repositioned in the pipe 22 using the rod and the bogey 37, energised as previously 23 described to support the seam and the next joint is 24 welded. 25 26 The process of line up, repositioning of the support 27 apparatus, and welding is repeated until a pipeline of 28 required length is obtained. 29 30 The support apparatus is then available for use in 31 welding a pipeline of substantially the same diameter 1 or for reconfiguration for use in welding pipes of a 2 different diameter. 3 4 The support apparatus 1 is suitable for use in 5 conjunction with the above-described mechanised line up 6 bed or another such facility. 7 8 Improvements and modifications may be made to the above 9 without departing from the scope of the invention.

26

Claims (15)

1 CLAIMS

2 3 1. A support apparatus for use in welding pipe 4 sections comprising a modular unit adapted to provide a circumferential support surface.

6 7

2. A support apparatus as claimed in Claim 1 adapted 8 to provide circumferential surfaces of various 9 sizes.

11

3. A support apparatus as claimed in Claim 1 or Claim 12 2 comprising a central body member, and extension 13 members having removable and replaceable elements.

14

4. A support apparatus as claimed in Claim 3 wherein 16 said extension members comprise a ram or rams.

17 18

5. A support apparatus as claimed in Claim 3 or Claim 19 4 comprising support means that describes the circumferential surface of the apparatus.

21 22

6. A support apparatus as claimed in Claim 5 wherein 23 said support means comprises a system of plate 24 members configured for relative movement.

26

7. A support apparatus as claimed in any preceding 27 claim comprising a single power distribution 28 source.

29

8. A support apparatus as claimed in any preceding 31 claim adapted to be powered hydraulically.

32 27 1

9. A support apparatus as claimed in any preceding 2 claim adapted to deliver pressure only to a weld 3 seam of the pipe and to no other area.

4

10. A mechanised line up bed comprising static pipe 6 holding and manoeuvring means; new pipe feed and 7 manoeuvring means; and means for manoeuvring the 8 back end of new pipe.

9

11. An internal pipe clamp system for supporting a weld 11 bead comprising support apparatus as claimed in the 12 preceding claim adapted for use in conjunction with 13 external pipe alignment means.

14

12. A method for facilitating welding of a joint 16 between two sections of pipeline comprising the 17 steps of: 18 identifying the internal diameter of the pipeline; 19 fitting appropriately sized extension members to a 20 body member to create a support apparatus; 21 positioning said support apparatus in the pipeline 22 beneath the joint to be welded; 23 supplying power to the support apparatus; and 24 forming the circumference of the support apparatus 25 tight against the joint. 26 27

13. A method as claimed in Claim 12 further including 28 the step of aligning said sections using a 29 mechanised test bed.

28 1

14. Support apparatus as hereinbefore described with 2 reference to or as shown in the accompanying 3 drawings. 4

15. A method for facilitating welding as hereinbefore 6 described with reference to or as shown in the 7 accompanying drawings.

8