Internal Mandrel Pipe Bending for Wrinkle-Free Reel-Lay
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Solution Overview
Problem
During spooling operations, lined pipes experience significant wrinkling and deformation issues due to the difference in material properties between the outer and inner walls, leading to challenges in alignment, fluid flow, and fatigue life, particularly in reel-lay applications where continuous bending is required.
Innovation Solution
An internal mandrel system is used to resist radially-inward deformation of the inner surface of the pipe by applying tension through a hold-back element and utilizing a pressure-equalisation duct to maintain pressure consistency, while the external mandrel imparts longitudinal bending curvature, effectively mitigating wrinkling and buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous bending of lined pipe is performed during spooling, then the pipe can be wound onto the reel, but wrinkling and deformation occur due to differential material properties between outer and inner walls
Solution Approach 1:
A fluid-filled chamber acts as an intermediary between the bending forces and the pipe wall. The fluid pressure distributes forces uniformly across the pipe's inner surface, preventing localized wrinkling while allowing continuous bending during spooling operations.
Solution Approach 2:
The patent changes the physical state and pressure parameters of the fluid within the chamber. By adjusting fluid pressure dynamically during the bending process, the system adapts to varying bending stresses and maintains optimal support conditions throughout the continuous spooling operation.
2Manufacturing precision
If high fluid pressure is applied within the chamber to prevent wrinkling, then pipe surface integrity is maintained, but alignment difficulty increases
Solution Approach 1:
The system employs dynamic pressure control where fluid pressure is adjusted in real-time based on the bending stage. During alignment phases, lower pressure eases positioning, while during active bending, pressure increases to prevent wrinkling, creating a dynamically adaptive support system.
Solution Approach 2:
The patent utilizes parameter changes in fluid pressure to resolve the contradiction. By varying pressure levels throughout the spooling cycle, the system provides low pressure during alignment operations for ease of positioning, then transitions to high pressure during bending to maintain surface integrity.
3Adaptability or versatility
If the chamber volume is increased to accommodate larger pipes, then applicability to different pipe sizes improves, but device complexity increases
Solution Approach 1:
The chamber is designed as a universal support structure that can accommodate various pipe diameters through adjustable positioning mechanisms. The same basic chamber design serves multiple pipe sizes by modifying fluid pressure distribution and chamber extension, eliminating the need for multiple specialized chambers.
Solution Approach 2:
The chamber is divided into segmented or modular sections that can be independently adjusted or extended. This segmentation allows the chamber volume to be scaled appropriately for different pipe sizes while maintaining a standardized base design, thereby managing complexity through modularity.
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 allows for continuous bending of lined pipes without significant wrinkling, ensuring smooth fluid flow and extended fatigue life by maintaining the structural integrity of the pipe during spooling and unspooling processes.
Implementation Method 1
resist radially-inward deformation of an inner surface of the pipe with respect to the longitudinal axis during bending
Implementation Method 2
a pressure-equalisation duct extending longitudinally through the internal mandrel for equalising pressure in the pipe section ahead of and behind the internal mandrel
Implementation Method 3
an elongate tensile hold-back element arranged to extend internally along the pipe section from an external anchor to the internal mandrel to hold the internal mandrel at a bending zone
Implementation Method 4
at least part of the pipe undergoes plastic deformation during bending along the longitudinal axis
Data Source
Figure 1~3
Figure 4~6
Figure 7~9
AI summary
A pipe-bending apparatus for bending an elongate pipe section (10) continuously along a longitudinal axis of the pipe section. The apparatus comprises: an internal mandrel (14) arranged to fit inside the pipe section to resist radially-inward deformation of an inner surface of the pipe section with respect to the longitudinal axis during bending; an elongate tensile hold-back element (18) arranged to extend internally along the pipe section from an external anchor (16) to the internal mandrel to hold the internal mandrel at a bending zone (24) as the pipe section advances longitudinally past the internal mandrel; an external mandrel defining the bending zone; and a drive for advancing the pipe section through the bending zone. A reel (12) serves as the external mandrel and as the drive.