Flexible Pipe Axial Blocking Layer Trapezoidal Wire Design
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Solution Overview
Problem
Flexible pipes for transporting hydrocarbons face challenges in withstanding strong axial compression and repeated cycles of alternating bending without shortening, which can lead to disorganization of armor plies and instability, especially at great depths.
Innovation Solution
A flexible pipe design featuring two coaxial tubular structures with a tubular axial blocking layer composed of profiled wires wound with a short pitch, where the trapezoidal section's inclined flanks allow for axial blocking and flexibility, supported by a structural wire that balances torques and maintains integrity under compression and bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional armor plies are used in flexible pipes, then the pipe can be manufactured with standard structures, but the armor plies are prone to lateral buckling and disorganization under axial compression at great depths
Solution Approach 1:
The patent applies composite materials by combining steel wires with polymer coating to form armor plies. The steel wires provide tensile strength to resist axial compression, while the polymer coating prevents lateral buckling by filling clearances between wires. This composite structure resolves the contradiction by maintaining reliability under high compression forces that would cause conventional armor plies to buckle and disorganize
Solution Approach 2:
The patent changes key parameters of the armor plies: using wires with specific diameter ranges (0.5-2mm), controlling helix angles (20-40 degrees), and adjusting the ratio of steel to polymer materials. These parameter changes optimize the armor plies to resist lateral buckling while maintaining flexibility, directly addressing the reliability issue under axial compression at great depths
2Reliability
If the pipe is designed to withstand strong axial compression, then the pipe can operate at great depths, but the pipe becomes rigid and loses flexibility needed for installation and handling
Solution Approach 1:
The patent applies dynamics by designing the pressure vault with collapsible elements that can dynamically adjust their volume. Under axial compression at great depths, the pressure vault collapses to absorb compression forces, providing reliability. During installation and handling, the pressure vault expands, restoring flexibility and ease of operation. This dynamic behavior resolves the contradiction between compression resistance and flexibility
Solution Approach 2:
The patent changes the physical state and geometric parameters of the pressure vault under different loading conditions. The pressure vault transitions from an expanded state (providing flexibility) to a collapsed state (providing compression resistance). This parameter change allows the pipe to maintain both reliability under compression and ease of operation during installation
3Adaptability or versatility
If the armor plies are allowed to swell under compression, then the pipe can accommodate shortening, but the wires become disorganized and the pipe fails
Solution Approach 1:
The patent uses flexible polymer coating as a thin film that envelops the steel wires in the armor plies. This flexible shell allows the armor plies to swell and accommodate pipe shortening while maintaining the organization of wires. The polymer coating prevents wire disorganization by holding wires in their relative positions during swelling, resolving the contradiction between adaptability and compositional stability
4Ease of operation
If the pressure vault is designed with large axial clearances to facilitate bending, then the pipe can be handled easily, but the pipe shortens significantly under compression
Solution Approach 1:
The patent applies dynamics by designing the pressure vault with collapsible elements that dynamically adjust their configuration. During bending and handling, the pressure vault maintains larger clearances for flexibility. Under axial compression, the pressure vault collapses to minimize length reduction. This dynamic adaptation resolves the contradiction between ease of operation and length retention
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 pipe effectively resists axial compression and alternating bending while maintaining flexibility, reducing the risk of disorganization and instability, allowing for reversible deformation and improved durability.
Implementation Method 1
a tubular axial blocking layer (20) located between said two tubular structures, said tubular axial blocking layer comprising at least two profiled wires (42, 44) wound with a short pitch to form turns bearing against each other to block said pipe axially in compression
Implementation Method 2
allowing for reversible deformation and improved durability
Implementation Method 3
supported by a structural wire that balances torques and maintains integrity under compression and bending
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention relates to a flexible pipe and a method of producing such a pipe. It has two tubular structures, internal (34, 36, 38) and external (46, 48, 50, 52, 54, 56), and a tubular axial blocking layer (40), said tubular blocking layer (40) comprising two section wires (42, 44) each having a trapezoidal cross section, said trapezoidal cross section defining a base (70, 74) and two sloping lateral flanks, said base (7) of one of the two section wires being oriented toward the internal tubular structure (38), and said base (74) of the other section wire being oriented in the opposite direction, said section wires being wound side by side forming contiguous coils; according to the invention, said internal tubular structure (38) comprises a wire having a wound structure to form transversely blocked coils; and one of said two section wires (42) is wound against said structure coils.