GB2040014A

GB2040014A - Bending limiting device for pipes

Info

Publication number: GB2040014A
Application number: GB8001704A
Authority: GB
Original assignee: Coflexip SA
Current assignee: Technip France SAS
Priority date: 1979-01-19
Filing date: 1980-01-18
Publication date: 1980-08-20
Also published as: NO155672B; NO800129L; BR8000339A; NO155672C; FR2446981B1; GB2040014B; FR2446981A1

Abstract

A bending limiting device which can be mounted at the end of a flexible tubular pipe 1 provided with a connecting end fitting 2, is constituted by an elongated tubular member 4 which can be engaged about the end fitting 2 and an adjacent part of the flexible tubular pipe means for fixing to the end fitting 2 and to the adjacent part of the flexible tubular pipe are provided and may comprise clips 5, 6, 12. The member 4 may comprise two semi-cylindrical halves (4a, 4b Figures 2, 3 not shown) connected about the pipe 1 and end fitting 2 by half-clips (5a, 5b, 6a, 6b Figures 2, 3) bolted together. <IMAGE>

Description

SPECIFICATION Bending limiting device for flexible pipes The present invention relates to a device for limited the bending of flexible tubular pipes fixed to a supporting member by a connecting end fitting.

Flexible tubular pipes and in particular those manufactured and marketed in large quantities by the Applicant company are widely used in the offshore oil industry, particularly for the collection and raising to the surface of hydrocarbons produced from underwater fields or for bringing about transfer connections for fluids between submerged devices, which may be fixed or movable on the sea bed or at different submergence depths and installations, which are fixed or move on the surface.

At their ends, said flexible pipes are connected to supporting members by connecting end fittings.

The flexible pipe is frequently connected to a substantially vertical supporting member, the flexible pipe leaving the latter at a large angle, often close to 900. As a result of the inertia of the pipe and tensile stresses exerted on it, the part of the pipe in the vicinity of the connecting end fitting tends to assume a very small radius of curvature, which creates dangerous stresses in the connecting area of the end fitting and the flexible pipe, which can lead to damage to the latter.

The present invention aims at providing a bending limiting device having a simple and economic construction and making it possible to prevent the disadvantage referred to hereinbefore.

As a novel industrial product, the present invention relates to a bending limiting device which can be mounted at the end of a flexible tubular pipe provided with a connecting end fitting, wherein it is constituted by an elongated tubular member which can be engaged about the end fitting and an adjacent part of the flexible tubular pipe and comprising means for fixing to the end fitting and to the adjacent part of the flexible tubular pipe.

According to a particularly advantageous embodiment, the tubular part of the bending limiting device is constituted by two semi-cylindrical portions which are preferably identical and assemblable by means of clips, constituted in each case by two half-clips joined by bolts and distributed over the length of the tubular member, the assembly of the clips by tightening the bolts simultaneously bringing about the fixing of the tubular member to the connecting end fitting and the adjacent part of the flexible tubular pipe.

According to a preferred embodiment, the tubular member is made from a plastics material having a high modulus of elasticity, such as that known for example under the trade name ADIPRENE L315, whilst the clips are metallic and are in the form of fittings embedded in the plastics material. The clip which is used for fixing to the end fitting can for example be constituted by two half-clips, each having two concentric peripheral walls joined to one another by spacers.

The internal diameter ofthe tubular member of the bending limiting device according to the invention is constant over the entire length of the part corresponding to the flexible tubular pipe and has at its end corresponding to the connecting end fitting a cross-section which assumes the shape of the latter.

This tubular member also has in cross-section a constant external diameter over a length corresponding to the connecting end fitting and part of the adjacent zone of the flexible pipe, said cross-section then decreasing progressively up to the end of the tubular member.

The total length L of the bending limiting device according to the invention can be determined by the following formula: 2:tR L = 360 x a in which R designates the admissible radius of curvature of the flexible tubular pipe under the action of the envisaged tensile stress, ct being the deflection angle compared with the vertical of the flexible pipe in the absence of the bending limiting device between its extreme positions at the envisaged installation position.

The invention is described in greater detail hereinafter relative to the non-limitative embodiments and the attached drawings, wherein show: Figure 1 in longitudinal section, a bending limiting device according to the invention fitted on a flexible pipe provided with an end fitting.

Figure 2 a section along the line Il-Il of Figure 1.

Figure 3 a section along the line Ill-Ill of Figure 1.

The drawings show the end of a flexible tubular pipe provided with a connecting end fitting having a peripheral groove 3.

The bending limiting device according to the invention incorporates an elongated tubular member 4 engaged about the connecting end fitting 2 and the adjacent part of the flexible pipe 1.

The internal diameter of the tubular member 4 is constant over the entire length of said member corresponding to the flexible pipe 1 and has, as is shown in Figure 1, at its end corresponding to end fitting 2 a cross-section which assumes the shape of the latter.

As can best be seen in Figures 2 and 3, the tubular member 4 is constituted by two identical semi-cylindrical parts 4a and 4b.

The device according to the invention has a plurality of clips 5 and 6, which are each constituted by two half-clips 5a, 5b or 6a, 6b assembled by bolts 9 which engage in corresponding recesses 8 made in the tubular member 4. Clip 4 engages in the peripheral groove 3 made on end fitting 2. The clips 6 are distributed over the entire length of tubular member 4.

As can be seen in Figure 2, clip 5 can advantageously be constituted by two half-clips 5a, 5b, each having two concentric peripheral walls 9 and 10 joined by spacers 11.

It is also advantageous to complete the fixing of the tubular member 4 to the flexible tubular pipe 1 by external peripheral clips 12 at the end of the tubular member 4 opposite to the end fitting 2.

These clips can be fitted level with corresponding interruptions made on the peripheral surface of the tubular member 4. The latter advantageously has a constant external diameter over a certain length 1 corresponding to the length of end fitting 2 and an adjacent area of the flexible tubular pipe, said diameter then decreasing progressively up to the opposite end of the tubular member 4.

According to a particular constructional embodiment, a bending limiting device is made with a tubular member 4 having a length of 31 63mm for a flexible pipe of external diameter 320.4mm, said tubular member having an external diameter of 562mm for a length 1 = 640mm, said diameter then progressively decreasing to a value of 350mm at the end of the tubular member. In addition to the mounting clip level with the end fitting, the tubular member has eight mounting clips distributed over its length.

Although the invention has been described with reference to a specific embodiment, it is clearly not limited thereto and various modifications can be made thereto without passing beyond the scope of the invention.

Claims

1. A bending limiting device which can be mounted at the end of a flexible tubular pipe provided with a connecting end fitting, wherein it is constituted by an elongated tubular member which can be engaged about the end fitting and an adjacent part of the flexible tubular pipe and comprising means for fixing to the end fitting and to the adjacent part of the flexible tubular pipe.

2. A bending limiting device according to claim 1, wherein the said elongated tubular member is constituted by two semi-cylindrical parts, which are preferably identical and assemblable by means of clips consituted in each case by half-clips joined by bolts and distributed over the length of the tubular member.

3. A bending limiting device according to claim 2, wherein the clips serving to fix the tubular member to the connecting end fitting is constituted by two half-clips, each having two concentric peripheral walls joined together by spacers.

4. A bending limiting device according to any one of the preceding claims, wherein the tubular member is made from a plastics material with a high modulus of elasticity, said clips being metallic and constructed in the form of fittings embedded in the plastics material.

5. A bending limiting device according to one or more of the preceding claims, wherein the internal diameter of the tubular member is constant over the entire length thereof corresponding to the flexible pipe and has at its end corresponding to the end fitting a cross-section assuming the shape of the latter.

6. A bending limiting device according to one or more of the preceding claims, wherein the tubular member has in cross-section a constant external diameter over a length corresponding to the end fitting and part of the adjacent area of the flexible pipe, said cross-section then decreasing progressively up to the end of the tubular member.