GB2344147A

GB2344147A - Encasing tubular component

Info

Publication number: GB2344147A
Application number: GB9825957A
Authority: GB
Inventors: Arthur Geoffrey Gibson; Arthur Robin Mableson
Original assignee: Vosper Thornycroft UK Ltd
Current assignee: Vosper Thornycroft UK Ltd
Priority date: 1998-11-26
Filing date: 1998-11-26
Publication date: 2000-05-31
Also published as: GB9825957D0

Abstract

The component 2, e.g. an oil or gas pipeline, is encased over e.g. a corroded region by an encasement 4 extending over two spaced sealing elements 6 and over the corroded region to form a reinforcement and a containment 8 for any fluid leaking from the component 2. Each element 6 may comprise a glass reinforced vinyl ester ring moulded directly on the component with a groove containing a compressed O-ring. Alternatively, the O-ring is directly applied to the component, the encasement 4 applied and, before it is cured, a circumferential steel or polymer strip is tightened around it at the seal to compress the latter. The encasement can be a glass fibre reinforced polymer.

Description

ENCASING TUBULAR COMPONENTS This invention relates to the encasing of tubular components and is particularly, although not exclusively, concerned with the repair or refurbishment of pipelines.

Over time, pipelines (such as oil and gas pipelines) may become corroded. Eventually, corrosion may extend right through the wall of the pipeline, and leakage will occur. Severely corroded sections of pipeline can be cut out and replaced, but this is costly and flow through the pipeline must be terminated while the repair takes place.

It is also possible to apply a surface covering to the corroded section of the pipeline. However, it is difficult to achieve a satisfactory bond between the corroded section of pipeline and a covering material, particularly if leakage has already taken place so that the outer surface of the pipeline is contaminated with, for example, oil. Consequently, a leakage path can exist between the pipeline itself and the covering, so permitting continuing leakage of the contents of the pipeline, with a resulting loss of pressure.

According to the present invention there is provided a method of encasing a tubular component, the method comprising fitting sealing elements at spaced locations along the tubular component and applying an encasing material over the sealing elements and over the tubular component between the sealing elements.

Preferably, means is provided for compressing the sealing elements radially into contact with the tubular component.

Each sealing element may comprise an elastomeric ring. Such rings may be formed in situ around the tubular component, for example by laying a bead of suitable material around the tubular component and butt-jointing the ends of the bead.

The encasing material may comprise a fibrereinforced polymer. In a preferred embodiment, the fibre-filled polymer is applied in situ over the tubular component and then allowed (or caused) to cure.

In an embodiment in accordance with the invention, a containment groove is provided on the tubular component for receiving each sealing element. The containment groove may be formed in situ, for example by applying a curable resin to the tubular component, and forming the containment groove in the curable resin. The curable resin may be fibre reinforced, for example it may be a glass reinforced vinyl ester.

In a preferred method, the containment ring may be moulded in situ on the tubular component, so as to form the containment groove between a portion of the ring and the outer surface of the tubular component.

In an alternative method in accordance with the invention, the sealing elements may be applied to the tubular component, following which the uncured encasing material is applied over the sealing elements and the region of the tubular component between the sealing elements. Subsequently, but before the encasing material has cured, a radially compressive force is applied to the sealing elements, for example by placing a circumferential clamping element over the uncured encasing material at the location of each sealing element and tightening the clamping element so as to press the sealing element firmly against the tubular component. The clamping element may, for example, comprise a strip of suitable material, such as steel or a polymer.

The present invention also provides an encased tubular component formed in accordance with the method defined above.

For a better understanding of the present invention, and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a cross-sectional view through a pipeline section having an encased region; Figure 2 shows part of the pipeline section of Figure 1 ; Figure 3 is an enlarged sectional view of part of the pipeline section; Figure 4 shows an alternative embodiment of an encased pipeline section.

Figure 1 shows a length of pipeline 2 having a covering or encasement 4. The encasement 4 extends over a length of the pipeline 2 which is corroded and so is leaking or likely to start leaking.

The encasement 4 is applied in situ. At opposite ends of the corroded region of the pipeline there are seals 6 which, together with the encasement 4, provide a containment system for containing any leakage which may take place across the wall of the pipeline and so penetrate between the pipeline 2 itself and the encasement 4. Such leakage is represented by the region 8 in Figure 1.

Each seal 6 comprises an 0 ring 10 (Figures 2 and 3) accommodated in a groove 12. The groove 12 is defined between the pipeline 2 and a moulded-on ring 14.

The ring 14 is made from a glass reinforced vinyl ester, and is moulded directly onto the pipeline 2.

The ring 14 has a base ring 16 engaging the pipeline 2 and a seal retaining ring 18 which is radially spaced away from the pipeline 2. The width of the groove 12 in the radial direction of the pipeline 2 is somewhat smaller than the unstressed thickness of the 0 ring 10, so that the O ring 10 is compressed so as to be in tight sealing engagement with the outer surface of the pipeline 2.

The encasement 4 is then applied over the pipeline 2 and the seals 6. The encasement 4 comprises a glass fibre reinforced polymer which bonds securely to the seals 6, and in particular to the outer surface of the ring 14. Consequently, there is a complete seal between the pipeline 2 and the encasement 4 at opposite ends of the containment region 8.

Figure 4 illustrates an alternative means for forming the seals at opposite ends of the containment region 8. In Figure 4, the 0 ring 10 is applied directly to the pipeline 2, without any retaining groove like that provided by the ring 14 in Figure 3.

Instead, the encasement 4 is applied over both the pipeline 2 and the 0 ring 10 and, before curing of the resin of the encasement 4, a radial compressive force is applied to the O ring 10. As shown in Figure 4, this is achieved by means of a circumferential strip 20 which is applied over the uncured encasement 4 at the axial position of the 0 ring 10. This strip 20 is then tightened to exert a clamping action on the encasement 4 and the O ring 10, to force the O ring 10 into tight sealing engagement with the outer surface of the pipeline 2. The strip 20 may be made of any suitable material such as steel or polymer, and may be removed after the material of the encasement 4 has cured.

Claims

1. A method of encasing a tubular component, the method comprising fitting sealing elements at spaced locations along the tubular component. and applying an encasing material over the sealing elements and over the tubular component between the sealing elements.

2. A method as claimed in claim 1, in which means is provided for compressing the sealing elements radially into contact with the tubular component.

3. A method as claimed in claim 1 or 2, in which each sealing element is an elastomeric ring.

4. A method as claimed in any one of claims 1 to 3, in which each sealing ring is formed in situ around the tubular component.

5. A method as claimed in claim 4, in which each sealing ring is formed by laying a bead of material around the tubular component and butt-jointing the ends of the bead.

6. A method as claimed in any one of the preceding claims, in which the encasing material is a fibre-reinforced polymer.

7. A method as claimed in claim 6, in which the fibre-filled polymer is applied in situ in an uncured form over the tubular component and then allowed or caused to cure.

8. A method as claimed in any one of the preceding claims, in which a containment groove is provided on the tubular component for receiving each sealing element.

9. A method as claimed in claim 8, in which the containment groove is formed in situ.

10. A method as claimed in claim 9, in which the containment groove is formed by applying a curable resin to the tubular component, and forming the containment groove in the curable resin.

11. A method as claimed in claim 10, in which the curable resin is fibre reinforced.

12. A method as claimed in claim 11, in which the curable resin is a glass reinforced vinyl ester.

13. A method as claimed in any one of claims 9 to 12, in which a containment ring is moulded in situ on the tubular component, so as to form the containment groove between a portion of the ring and the outer surface of the tubular component.

14. A method as claimed in any one of claims 1 to 7, in which the sealing elements are applied to the tubular component, following which the uncured encasing material is applied over the sealing elements and the region of the tubular component between the sealing elements.

15. A method as claimed in claim 14, in which before the encasing material has cured, a radially compressive force is applied to the sealing elements.

16. A method as claimed in claim 15, in which the radially compressive force is applied by placing a circumferential clamping element over the uncured encasing material at the location of each sealing element and tightening the clamping element so as to press the sealing element firmly against the tubular component.

17. A method as claimed in claim 16, in which the clamping element comprises a strip of material.

18. A method of encasing a tubular component as claimed in claim 1 and substantially as described herein.

19. A tubular component encased in an encasing material, the tubular component having sealing elements situated at spaced positions along the tubular component and the encasing material extending over the sealing elements and over the tubular component between the sealing elements.

20. A tubular component substantially as described herein, with reference to and a shown in Figure 1 and Figures 2 and 3 or Figure 4 of the accompanying drawings.