Pinned composite pipe end-fitting

Abstract

A composite pipe termination is provided. The composite pipe includes a composite pipe wall thickness and a cut end. An annular part of composite material is attached around the outside of the composite pipe at the cut end. The annular part has a radial thickness which tapers towards the composite pipe in the direction along the composite pipe away from the cut end to provide an exterior surface having a tapered portion. A pinning structure includes one or more pins which extend through the annular part and partially through the composite pipe wall thickness to further attach the annular part to the composite pipe.

Claims

1. A method of providing a composite pipe end fitting, comprising: providing a composite pipe having a composite pipe wall thickness including a liner; cutting the composite pipe to a desired length to expose a cut end; attaching additional composite material in the form of an annular part around the outside of the composite pipe at the cut end; tapering a radial thickness of the annular part towards the composite pipe in a direction along the composite pipe away from the cut end to provide an exterior surface having a tapered portion; providing one or more bores, the bore or each bore extending through the annular part and partially through the composite pipe wall thickness providing pinning means comprising a close-fitting pin corresponding to the bore or each bore; further attaching the annular part to the composite pipe by introducing a close-fitting pin into the bore or each bore; providing an annular metal sleeve having an interior surface configured to mate with the exterior surface of the annular part including the tapered portion and having an annular extension portion, configured to extend beyond the cut end; forcing the annular part into the annular metal sleeve to generate a high axial and radial pre-load between the annular part and the annular metal sleeve; providing a transition piece, the transition piece directly mates with and has a proximal flange which mates with the cut end within the extension portion and a distal connector for attachment to a metal pipe, for interfacing with the metal pipe and locking means for locking the transition piece to the annular extension portion, the transition piece having a conduit therethrough to allow fluid communication between the transition piece and the composite pipe and between the transition piece and any connected metal pipe; and locking the transition piece into sealing engagement with the annular extension portion using the locking means.

2. The method of claim 1, comprising configuring the bore or each bore to extend less than or equal to 80% of the way through the composite pipe wall thickness.

3. The method of claim 1, comprising configuring the bore or each bore to extend radially.

4. The method of claim 1, comprising providing two or more bores arranged to form one or more circumferential lines of bores around the annular part.

5. The method of claim 4, comprising arranging the bores in the circumferential line or in each circumferential line to be spaced equidistantly from one another.

6. The method of claim 4, comprising providing the circumferential line of bores or each circumferential line of bores with an even number from 2 to 36 bores.

7. The method of claim 4, comprising providing more than two circumferential lines of bores and arranging the circumferential lines of bores to be spaced equidistantly from one another.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be further described, by way of example only, and with reference to the accompanying drawings, in which:

(2) FIG. 1 illustrates a side view of a composite pipe termination according to the invention.

(3) FIG. 2 illustrates a cross-section through A-A of the composite pipe of FIG. 1.

(4) FIG. 3 shows side view of a composite pipe end fitting according to the invention, comprising a composite pipe termination according to the invention.

DETAILED DESCRIPTION

(5) A detailed description of the invention will now be provided with reference to the above figures.

(6) FIG. 1 shows an embodiment of a composite pipe termination comprising a composite pipe (1), which extends to the cut end (2). A built up region at the cut end forms an annular part (3) around the outside of the cut end. The annular part (3) comprises a portion of constant maximum radial thickness (4) adjacent to the cut end and a tapered portion (5) adjacent to the portion of constant maximum radial thickness, which tapers towards the composite pipe in the direction along the composite pipe away from the cut end. The annular part (3) according to this embodiment comprises a further portion of constant thickness (6) and a further tapered portion (7).

(7) A composite pipe bore (8) extends through the composite pipe (1) to the cut end (2). Radially extending bores (9) have been provided through the annular part, each bore (9) also extending partially through the composite pipe wall thickness. All of the bores (9) according to this embodiment extend partially through the pipe wall thickness to terminate at the same radial depth. The bores (9) according to this embodiment have been provided in fourteen circumferential lines, each line comprising twelve of bores spaced equidistantly from one another, as can be seen from FIG. 2, although the number of circumferential lines of bores and the number of bores in a circumferential line are purely exemplary. Pinning means comprising close-fitting pins (10) are shown already in place inside the majority of bores (9) in FIGS. 1 and 2 to further attach the annular part to the composite pipe. In addition, one pin (10), in the case of FIG. 1, and three pins (10), in the case of FIG. 2, are shown ready to be forced into the bores (9) using methods known to the skilled person.

(8) FIG. 3 shows a composite pipe end fitting, comprising the composite pipe termination illustrated in FIGS. 1 and 2, whereby pinning means has been provided, comprising a close-fitting pin (10) driven into each radial bore (9). A reference numeral in FIG. 3 which is the same as a reference numeral used in FIGS. 1 and 2 has the same meaning as applies to those figures.

(9) As shown in FIG. 3, an annular metal sleeve (11) is provided having an interior surface which mates intimately with the exterior surface of the annular part including, importantly, the tapered portion. The annular metal sleeve also comprises an extension portion (12) which extends beyond the cut end (2) and which comprises a thread on its interior surface. The composite pipe termination has been forced into the annular metal sleeve using tools known to the skilled person, such as hydraulic tools, to generate a high axial and radial pre-load. The annular metal sleeve has then been locked to a transition piece (13) by means of a locking ring (14). The locking ring (14) comprises a thread on an exterior surface which cooperates with the thread on the interior surface of the extension portion (12), such that the locking ring (14) may be threaded onto the extension portion (12) to lock the transition piece (13) to the annular metal sleeve and lock the two together. The transition piece (13) comprises a conduit (15) therethrough, a proximal flange (16) which mates with the cut end of the composite pipe (and also the annular part adjacent the cut end), and a distal connector (17) suitable for attachment to a metal or other pipe (not shown). The proximal flange (16) is forced against the cut end (2) by the locking ring (14). The distal connector (17) in FIG. 3 is a further flange. Pressure-energised sealing means (not shown), such as an O-ring, a gasket or a bore seal, ensure a fluid-tight seal.