GB2194006A

GB2194006A - Annular seal

Info

Publication number: GB2194006A
Application number: GB08719272A
Authority: GB
Inventors: Philip George; Theodore Leonards; Stephen Michael Vick; Michael Bland
Original assignee: CRUX ENGINEERING Ltd; DEEPWATER FOUNDATION CONSULTAN
Current assignee: CRUX ENGINEERING Ltd; DEEPWATER FOUNDATION CONSULTAN
Priority date: 1986-08-14
Filing date: 1987-08-14
Publication date: 1988-02-24
Anticipated expiration: 2007-08-14
Also published as: GB8619783D0; GB8719272D0; GB2194006B

Abstract

A seal for closing an annular opening, particularly between a pile 10 and a pile sleeve 12 of an offshore structure, uses an annular seal element 26 of resilient material. This has a cavity 32 (preferably in a radially outer head portion 30) which permits deformation to facilitate engagement in a narrow-mouthed channel 20 of a housing 14. Subsequently the cavity 32 is filled, thus reducing deformability end locking the element 26 to the housing 14. The housing 14 may be welded to a pile sleeve 12, then receive the seal element 26. After this is filled, the pile 10 is passed through sealingly. <IMAGE>

Description

SPECIFICATION Annular seal The present invention relates to an annular seal, and particularly to an annular seal suitable for use to retain grout within an annular cavity between a pile and a pile sleeve of an offshore structure. Such seals may also be useful for many other purposes where seals are required between a tube and a coaxial core member, e.g. in the fields of conductors and pipelines.

In one aspect the invention provides an annular seal comprising an annular seal element having a radially outer head portion from which a body portion extends inwardly; the body portion being relatively deformable resiliently so that the seal element can be engaged within a tubular element which it engages with its head portion, and an inner member can be passed through the tubular element and seal element, deforming the body portion and becoming resiliently and sealingly engaged thereby. Preferably the seal element is resili ently deformable and has a cavity whereby it is relatively deformable to facilitate installation; the cavity being fillable with a filling material after installation so as to reduce the deformability.Thus a seal element can be provided which can be deformed to permit location within a pile sleeve extension; subsequently its cavity can be filled from outside the sleeve extension so that the element is fixed in place. The head portion may be adapted to be engageable by seal locating means. The cavity may be substantially within the head portion, which is thus of variable deformability so that it can be engaged by seal locating means and then locked in place.

The annular seal may include an annular seal housing member which may provide said locating (and fixing) means. The seal locating means may define a narrow-mouthed channel, such that in use the seal element extends through the mouth to bridge the annular cavity to be sealed. The channel may have inlet means which communicate with the cavity of the annular seal element when this is engaged therein.

In another aspect the invention provides a method of sealing by means of an annular seal of the above type. The method may in clude a step of connecting an annular seal housing member to a structure, preferably prior to engagement of an annular seal element therein.

In further aspects the invention provides an annular seal assembly (which may comprise a seal housing member, a seal element, and a filling material within the cavity thereof); and an annular assembly including an annular seal of the above type.

An embodiment of the invention will now be described in greater detail with reference to the accompanying drawings in which: Fig. 1 is a schematic sectional view of an annular seal assembly embodying the invention; and Fig. 2 is a like view showing just the seal element in its unstressed state.

Fig. 1 shows a grout seal which is an annular seal between a pile 10 and a pile sleeve 12 of an offshore structure. The pile 10 has been driven through the pile sleeve 12 so that it projects beneath. A seal housing member in the form of a seal can 14 is secured (suitably by welding) beneath the pile sleeve 12. The can 14 is annular and embraces the pile 10. It is outwardly stepped (16) so that the annular cavity 18 is wider than that between the sleeve 12 and the pile 10. The can 14 has a seal locating channel 20 formed by a pair of annular ribs 22 which project inwardly and convergingly. In the outer wall of the can 14 where this constitutes the base of the channel 20, there are one or more inlets 24.

The annular seal element 26 has a body 28 which, in axial section, is elongate. At the radially inner region there is an enlargement 29. At the other (outer) end, it has an enlarged head 30. This head 30 has an annular cavity 32, which opens in the radially outer face 34 of the head 30 (which is the radially outer face of the annular element 26). The seal element 26 is made largely of a resilient material, such as a synthetic rubber, but may have reinforcing members, e.g. steel wires.

These may include coaxial rings 36, and generally radially extending members 38.

The cavity 32 occupies quite a large proportion of the volume of the head 30. Thus the head is quite easily deformable, and it can be compressed so that it can be passed through the narrow mouth of the channel 20 so as to locate the seal. Once the seal element 26 is engaged in the channel, a settable filling composition (such as an epoxy/polymer material) can be injected into the cavity 32 via the opening 24. Once this has set, the seal element is locked in place, since the head 30 now cannot readily be compressed so as to be withdrawn from the narrow-mouthed channel 20.

The engagement of the seal element 26 (which may include filling the cavity) is generally effected before the pile 10 is in place.

When that is driven through the sleeve 12, the body 28 of the seal element is bent round, and becomes resiliently urged against the outer face of the pile 10 as shown in Fig.

1. Depending on the relative dimensioning of the seal element 26, it may engage the pile 10 largely by means of bending stress, or hoop stress, or both.

Thus the invention provides seals that can be made and installed simply. The separate elements (seal can and seal element) can be manufactured by their respective specialists with a high degree of quality assurance and quality control. The components are simple and rugged, so there is little danger of damage during transport, storage, installation and actual use. The seal can can be welded to the pile sleeve before the seal element is attached, so it is in no danger of being damaged by heat. When such a seal assembly is used as a grout seal, it is no longer necessary to install costly sealing service lines to the top of an offshore structure (which lines have subsequently to be removed). The seal is easy to inspect and test on site; there is no need for the costly testing of seals in the yard.

Claims

1. An annular seal comprising an annular seal element having a radially outer head portion from which a body portion extends inwardly; the body portion being relatively deformable resiliently so that the seal element can be engaged within a tubular element which it engages with its head portion, and an inner member can be passed through the tubular element and seal element, deforming the body portion and becoming resiliently and sealingly engaged thereby.

2. An annular seal according to claim 1 wherein the seal element has a cavity whereby it is relatively deformable to facilitate installation; the cavity being fillable with a filling material after installation so as to reduce the deformability.

3. An annular seal according to claim 2 wherein the cavity contains filling material.

4. An annular seal according to claim 2 or 3 wherein the cavity is substantially within the head portion, which is thus of variable deformability so that it can be engaged by seal locating means and then locked in place by filling the cavity.

5. An annular seal according to any preceding claim including an annular seal housing member which provides seal locating means in which the head portion is engageable by resilient deformation.

6. An annular seal according to claim 5 in which the seal locating means defines a narrow-mouthed channel, such that in use the seal element extends through the mouth to bridge the annular cavity to be sealed.

7. An annular seal according to claim 6 in which said channel has inlet means which communicate with the cavity of the annular seal element when this is engaged therein.

8. An annular seal according to claim 5,6 or 7 in which the seal housing member is a seal can having a first tubular portion for connection to a pile sleeve and a second tubular portion of larger diameter which provides the seal locating means.

9. An annular seal substantially as herein described with reference to and as illustrated in the accompanying drawings.

10. A method of closing an annular opening comprising providing an annular seal according to any preceding claim, and arranging it so that the seal element is resiliently urged to close the opening sealingly.

11. A method according to claim 10 wherein the annular seal is according to claim 5 and wherein the seal element is engaged by the seal locating means; the cavity is filled to lock the element in place; and then the element is resiliently deformed to close said opening sealingly.

12. A method according to claim 10 or 11 wherein the annular opening to be closed is between a pile and a pile sleeve; wherein the annular seal is according to claim 8; and wherein the first tubular portion of the seal can is welded to the pile sleeve, and subsequently the pile is driven through the sleeve and through the seal element engaged therein.

13. A method of closing an annular opening substantially as herein described with reference to and as illustrated in the accompanying drawings.