Flexible Pipe End Fitting Sealing via Pre-formed Armor Trajectory
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Solution Overview
Problem
Existing connection end pieces for flexible tubular pipes in offshore oil and gas fields face fatigue issues due to high tension variations and work-hardening during manufacturing, leading to potential wire breakage at critical zones.
Innovation Solution
A connection end piece design featuring an annular chamber filled with a filling material, where the sealing and crimping means are arranged between the front edges of the armor's spaced parts and the end arch, incorporating an annular ring with a tapered front part and stop ring, and the armor's trajectory is modified to maintain a large radius of curvature, reducing bending stresses and eliminating the need for folding and unfolding during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the armor is folded and unfolded during assembly of the connection end piece, then the sealing and crimping of the pressure sheath can be achieved, but work-hardening occurs during manufacturing leading to reduced fatigue strength and potential wire breakage
Solution Approach 1:
The armor is pre-formed with a helical trajectory and large radius of curvature before assembly. This preliminary configuration ensures that during the sealing and crimping process, the armor does not need to be folded or unfolded, thereby avoiding work-hardening and preserving fatigue strength while still enabling effective sealing and crimping of the pressure sheath.
2Strength
If the armor trajectory is modified to maintain large radius of curvature, then bending stresses are reduced and fatigue resistance is improved, but the device complexity increases due to additional forming requirements
Solution Approach 1:
The armor trajectory is designed with specific parameter changes - maintaining a large radius of curvature and helical path - which reduces bending stresses during operation. This parameter optimization improves fatigue resistance while the forming process is integrated into the manufacturing workflow, managing the complexity through standardized procedures.
3Reliability
If the connection end piece is designed to withstand high tension variations, then reliability in marine environment is improved, but the structural complexity increases requiring additional components like annular ring and stop ring
Solution Approach 1:
The connection end piece is segmented into functional components: the annular ring provides structural support and tension distribution, the stop ring prevents over-displacement, and the armor layers provide tensile strength. This segmentation allows each component to be optimized for its specific function, enabling the assembly to withstand high tension variations while keeping individual components relatively simple.
4Ease of manufacture
If the armor is crimped below the end parts to access crimping means, then the pressure sheath can be sealed, but the armor must be folded and unfolded causing work-hardening and fatigue issues
Solution Approach 1:
The armor is pre-configured with a helical trajectory and appropriate clearance before the crimping operation. This preliminary arrangement allows the crimping means to be accessed without requiring the armor to be folded or unfolded, thereby maintaining armor fatigue strength while still achieving effective sealing of the pressure sheath.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the connection end piece's ability to withstand high average tension and numerous cycles of voltage variation, improving fatigue resistance and preventing wire breakage by maintaining a consistent radius of curvature and avoiding the need for folding, which reduces work-hardening and increases the armor's fatigue strength.
Implementation Method 1
an annular chamber filled with a filling material, in which extend the spaced parts of the armor
Implementation Method 2
this because of the method of manufacturing the hook. In order to reduce the level of tension at the level of each hook, friction between the weaves and the resin is used, as well as the capstan effect.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a connection end fitting (10) for a flexible tubular pipe of the unbounded type notably comprising an internal pressure sheath (3) and at least one tensile pressure armour layer (5, 6) which are wound at long pitch and each comprise a forward edge (22) formed on a part spaced away from a point of detachment (21) of said internal sheath, said end fitting comprising an end vault (11) and a cylindrical cap (15) forming an annular chamber (17) filled with a filler material and into which the separated parts (20) of the armour layers (8) extend, characterized in that the end fitting (10) also comprises means (30) of sealing and crimping the pressure sheath (3) which are positioned between the forward edges (22) of the separated parts (20) of the armour layers (8) and the end vault (11) after this end fitting (10) has been fitted onto the pipe (1).