GB2027507A

GB2027507A - Pipe aligning devices

Info

Publication number: GB2027507A
Application number: GB7908964A
Authority: GB
Original assignee: GKN Bolts and Nuts Ltd
Current assignee: GKN UK Investments Ltd
Priority date: 1978-03-22
Filing date: 1979-03-14
Publication date: 1980-02-20
Also published as: GB2027507B

Abstract

A device for bring together into alignment two flanged pipes is intended to engage in bolt holes of flanges of the pipes and to pull the pipes towards each other and into alignment. A guide member 17 incorporates centralising members 18 and 38 for engaging in and aligning bolt holes 15 and 16 and also incorporates a tapered lead-in portion 37 for bringing the flanges into alignment. The two flanges are driven together by means of a hydraulic piston and cylinder assembly 24 mounted between an abutment 26 on the guide member and an abutment 34 bearing against one pipe flange. <IMAGE>

Description

SPECIFICATION Pipe aligning devices The invention relates to pipe aligning devices for bringing together into alignment two pipes of the kind having end flanges with bolt holes for assembling the two pipes together.

When pipes of this kind have to be assembled together in an environment where it is difficult to work, for example on the sea bed, it is difficult when handling the pipes to ensure that they are brought closer together than about one metre and it is also difficult to ensure that the correct alignment of the pipes is established.

An object of the invention is to provide a device for assisting in the aligning and bringing together of two such pipes which have previously been positioned approximately end to end.

The invention provides a pipe aligning device for bringing together into alignment two pipes of the kind having end flanges with bolt holes for assembling the two pipes together, the aligning device comprising a guide member arranged to extend into bolt holes in flanges of two adjacent pipes, a first centralising member on the guide member for insertion in a bolt hole in a first flange of the first pipe, a second centralising member on the guide member arranged to engage a bolt hole of the flange of the second pipe when the pipes have been brought together so as to hold the pipes in alignment, a narrow portion of the guide member arranged to pass through a bolt hole of the flange of the second pipe with a clearance, a lead-in portion of the guide member tapering from a transverse dimension corresponding generally to the size of the centralising members at its end directed towards the centralising members to a smaller transverse dimension adjacent the narrow portion of the guide member and means to drive the guide member towards the flange of the first pipe whereby the tapered lead-in portion and subsequently the second centralising member can bring and then maintain the bolt holes of the two flanges in alignment.

Preferably the aligning device comprises a first abutment assembly arranged to prevent the first guide member from being pulled out of the first flange towards the other pipe, a hydraulic cylinder assembly connected to the guide member beyond the flange of the second pipe and a second abutment assembly between the piston and cylinder assembly and the flange of the second pipe.

Each abutment assembly may incorporate a spherical bearing block and a corresponding spherical bearing seat so as to provide an effective abutment despite misalignment of the guide member with respect to the flange.

The connection of the piston and cylinder assembly to the guide member may be adjustable so that after the piston and cylinder assembly has been operated to draw the two pipes together by a distance equal to the stroke of the assembly, its position can be readjusted on the guide member to enable it to bring the two pipes more closely together.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawing which is; A diagrammatic side elevation partly in section of a pipe aligning device in use between two pipes to be brought together.

A first pipe 11 with a flange 12 has been installed in its desired location on the sea bed.

A second pipe 13 with a flange 14 is intended to be connected to the pipe 11. The pipe 13 has been lowered from a ship or barge to approximately its desired location and its mobility is assisted by providing buoyancy bags within the pipe. The desired alignment is such that bolt holes such as 15 in flange 12 should be aligned with bolt holes such as 16 in flange 14. Some deviation from coaxial alignment between the two pipes may be desired and can be catered for due to the fact that at least one of the flanges 12, 14 is arranged on the end of its pipe with a facility to swivel through a limited angle. The two pipes are shown in positions of proximity which are typical of the accuracy of positioning which can be achieved without difficulty simply by lowering the second pipe. The distance apart of the two pipes is of the order of but perhaps somewhat less than one metre.

An alignment device for bringing together the two pipes 11 and 13 is also shown. The alignment device incorporates a guide member 17 extending between and passing through the bolt holes 15 and 16 of the two flanges. The guide member incorporates a first integral centralising member 18 which is disposed within the bolt hole 15 with a clearance of the order of 3mm and is held in position against tension in the guide member by means of a first abutment assembly 19 arranged between an end portion of the guide member and an end face of the flange 12.

The abutment assembly comprises a spherical bearing block 21 and a spherical bearing seat 22 so that the abutment assembly provides an effective abutment even when the guide member is not in axial alignment with the flange 12.

The part of the guide member which passes through the flange 14 is a narrow portion constituted by a connecting rod 23. The diameter of the connecting rod is substantially smaller than the diameter of the bolt hole 16 so that the connecting rod can pass through the bolt hole at a range of angles. The connecting rod 23 also carries at a position beyond the flange 14, a piston and cylinder assembly 24. The piston and cylinder assem bly incorporates a cylinder 25 which has a central bore through which the connecting rod 23 passes, a nut 26 on the connecting rod with a spherical seating member 30 holding the cylinder in position. The cylinder is provided with an annular piston 27 which operates between inner and outer parts of the cylinder. A hydraulic pressure supply 28 is provided to pressurise the working chamber of the cylinder to drive the piston in a direction out of the cylinder.The piston is sealed within its cylinder by means of a main seal 29. The wall thickness of the piston 27 is stepped so that only a small portion adjacent the working volume of the cylinder slides on the cylinder.

At its opposite end, the cylinder has a bearing ring 31 incorporating seals 32 and this bearing ring is of slightly smaller diameter than the outer working diameter of the cylinder so that it engages with and supports the narrower diameter portion of the piston. The step in the piston together with the bearing ring 31 provides a second annular chamber within the cylinder which can be pressurised through a hydraulic connection 33 to provide a return stroke for the cylinder.

The outer end of the piston 27 is arranged to bear against a second abutment assembly 34 comprising a spherical bearing block 35 and a spherical bearing seat 36. By means of this abutment assembly the piston can operate against the flange 14 so that during the working stroke of the cylinder assembly the piston 27 drives the flange 14 towards the flange 12.

In order to assist accurate alignment of the bolt holes 1 5 and 16 as they come together, the guide member incorporates a conical tapered lead-in section 37 which at its end arranged towards the flange 12 has a transverse dimension corresponding generally to the diameter of the bolt holes, i.e., has a small clearance of the order of 3mm. The lead-in section 37 tapers towards its opposite end to a transverse dimension which is only slightly greater than the diameter of the connecting rod 23. Thus as the flange 14 approaches the flange 12, it tends to be brought into alignment with the flange 12 by the action of the tapered lead-in section 37 on the bolt hole 16.

Between the tapered lead-in section 37 and the flange 12, the general diameter of the guide member is reduced slightly as compared with the maximum diameter of the tapered lead-in section (and the bolt hole diameter) and this slightly reduced diameter portion carries a second integral centralising member 38, similar to centralising member 18 for engagement in the bolt hole 16 of flange 14. This centralising member 38 acting in the bolt hole 16 together with the centralising member 18 in bolt hole 15 aligns the bolt holes within acceptable limits, the actual degree of alignment depending on the angle of the guide member with respect to the axes of the bolt holes.

When aligning two pipes together, it is convenient to employ three pipe aligning devices arranged in corresponding pairs of bolt holes around the diameters of the flanges. In use, the aligning devices are set up in the two pipe flanges as shown and the cylinders are pressurised through inlets 28 to drive the flange 14 and its pipe 13 towards the flange 12 and pipe 11. When the pistons have extended the full length of their strokes, further movement of the flange 14 towards flange 12 may still be required. To achieve this, one cylinder at a time is depressurised, has its piston retracted by pressurising port 33 and is then moved along the connecting rod 23 by means of nuts 26 until the retracted piston is again held close up against the second abutment assembly 34.When this operation has been completed for all three aligning devices, they are again all pressurised through inlet ports 28 so that further progress of the flange 14 occurs towards the flange 12. This whole operation is completed as many times as necessary to bring the flanges into engagement.

As the two flanges come close together, the tapered lead-in section 37 first assists in more accurate alignment of the two flanges and subsequently the centralising member 38 ensures sufficiently close alignment. Once the flanges have been brought together the two flanges are held together by bolts inserted but not fully tightened in other bolt holes which do not have pipe aligning devices. The flanges themselves may have seats which assist in final alignment. At that stage each first abutment assembly 19 is detached from its guide member and the aligning devices are removed. The slight looseness allows limited movement between the two flanges to facilitate removal of the aligning devices.When the aligning devices have been removed, further bolts are inserted in their places and all of the bolts with their corresponding nuts are tightened down in the usual way to bring the flanges 12 and 14 into engagement.

From the above description of the operation of the device it can be seen that it is important for the two centralising members to be of such a form as to allow angular movement between the guide member and the flanges.

This is achieved by the relatively short length and radiused profile of these centralising members as shown in the drawing. The angular movement is necessary for centralising member 18 when first setting up the aligning device to cater for misalignment between the two pipes and their flanges. Subsequently, angular movement is necessary between centralising member 38 and flange 16 to cater for continued slight misalignment as the flanges approach each other and further angular movement may be necessary for centralis ing member 38 as centralising member 18 transfers from flange 12 to flange 14 across an appropriate gap during removal of the guide member.

Claims

1. A pipe aligning device for bringing together into alignment two pipes of the kind having end flanges with bolt holes for assembling the two pipes together, the. aligning device comprising a guide member arranged to extend into bolt holes in flanges of two adjacent pipes, a first centralising member on the guide member for insertion in a bolt hole in a first flange of the first pipe, a second centralising member on the guide member arranged to engage a bolt hole of the flange of the second pipe when the pipes have been brought together so as to hold the pipes in alignment, a narrow portion of the guide member arranged to pass through a bolt hole of the flange of the second pipe with a clearance, a lead-in portion of the guide member tapering from a transverse dimension corresponding generally to the size of the centralising members at its end directed towards the centralising members to a smaller transverse dimension adjacent the narrow portion of the guide member and means to drive the guide member towards the flange of the first pipe whereby the tapered lead-in portion and subsequently the second centralising member can bring and then maintain the bolt holes of the two flanges in alignment.

2. A pipe aligning device as claimed in Claim 1 including a first abutment assembly arranged to prevent the first guide member from being pulled out of the first flange towards the other pipe, a hydraulic cylinder assembly connected to the guide member beyond the flange of the second pipe and a second abutment assembly between the piston and cylinder assembly and the flange of the second pipe.

3. A pipe aligning device according to Claim 2 wherein each of the abutment assemblies incorporates a spherical bearing block and a corresponding spherical bearing seat so as to provide an effective abutment.

4. A pipe aligning device according to any preceding claim wherein the connection of the piston and cylinder assembly to the guide member is adjustable along the length of the guide member.

5. A pipe aligning device substantially as described with reference to and as illustrated by the accompanying drawing.