Sacrificial Insert Shielding for Flexible Pipe Carcass Erosion
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Solution Overview
Problem
Conventional flexible pipes face erosion issues due to abrasive particles in transported fluids, leading to potential failure, especially in deep-water environments where operational conditions are extreme, and the direction of fluid flow can cause uneven wear patterns.
Innovation Solution
A sacrificial insert is helically wound over the inner surface of the carcass layer, providing erosion protection by shielding the flow-facing edge regions with a tape element that has a specific cross-section design, such as a T-shaped or C-shaped folded strip, to cover the edges of the windings and present a uniform surface profile regardless of flow direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flexible pipe is used to transport abrasive fluids, then the pipe can perform basic transport function, but the carcass layer suffers erosion from abrasive particles leading to reduced service life
Solution Approach 1:
The patent applies the sacrificial insert principle by introducing a replaceable, erosion-resistant component that is deliberately designed to be consumed or degraded before the main carcass layer. This sacrificial element absorbs the erosive attack from abrasive particles, protecting the expensive and critical carcass layer. When the insert erodes, it can be replaced without replacing the entire pipe, thus extending the overall service life while maintaining reliability.
Solution Approach 2:
The sacrificial insert acts as an intermediary barrier between the abrasive fluid and the carcass layer. It mediates the harmful interaction by positioning itself in the flow path to intercept abrasive particles before they can directly contact and erode the carcass layer, thereby protecting the structural integrity of the pipe.
2Reliability
If thicker carcass layer is used to compensate for erosion, then erosion protection is improved, but the pipe diameter and complexity increase
Solution Approach 1:
The patent segments the erosion protection function from the structural carcass layer by introducing a separate sacrificial insert component. This segmentation allows the erosion protection to be provided by a dedicated element with appropriate material properties, while the carcass layer can maintain its original thickness and structural design without needing to be over-engineered for erosion resistance.
Solution Approach 2:
The sacrificial insert provides localized erosion protection precisely where it is needed - in the flow path where abrasive particles directly impact the carcass layer. This targeted approach means that erosion protection is enhanced only in the critical areas without requiring a uniform increase in carcass layer thickness throughout the entire pipe structure.
3Reliability
If specialist erosion-resistant materials are used for carcass layer, then erosion resistance is improved, but manufacturing cost increases
Solution Approach 1:
The sacrificial insert is designed as a cost-effective, erosion-resistant component that can be manufactured from specialized materials without significantly increasing overall pipe cost. Since the insert is replaceable and has a limited service life, using high-performance erosion-resistant materials for this component is economically justified, as it protects the much more expensive carcass layer and avoids premature pipe failure.
Solution Approach 2:
The patent creates a composite structure combining the sacrificial insert material with the carcass layer material. The insert can be made from cost-effective erosion-resistant materials such as hardened steel or ceramic-coated materials, while the carcass layer uses standard flexible pipe materials. This composite approach provides enhanced erosion resistance at a reasonable cost by strategically placing specialized materials only where they are most needed.
Data Source
AI summary
A method and apparatus are disclosed for providing erosion protection to self-interlocking windings of a carcass layer of a flexible pipe. The method includes the steps of, via a wound sacrificial insert located over at least a portion of an inner facing surface of self-interlocking windings of a carcass layer, shielding at least a flow facing edge region of each self-interlocking winding from abrasive elements carried by a bore fluid flowing along a bore of the flexible pipe from an upstream to a downstream location.