Composite Pipe End Fitting With Transition Seal for Subsea Termination
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Solution Overview
Problem
Composite pipes used in the oil and gas industry face challenges in reliable termination and connection to non-composite piping due to differences in structural properties and thermal expansion, leading to instability and sealing issues in hostile subsea environments.
Innovation Solution
An apparatus comprising a composite pipe with a liner layer and composite layer, an annular transition element, and a connector with compression means that compresses the liner extension piece into sealing engagement with the transition element, ensuring fluid communication and stability, utilizing materials like PEEK and carbon fibers, and incorporating a metal collar and crimping sleeve for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If composite pipe material is used, then resistance to aggressive fluids and harsh environmental conditions is improved, but reliable termination and connection to non-composite piping becomes difficult
Solution Approach 1:
A transition piece is introduced as an intermediary component between the composite pipe and the steel flange. The transition piece has a first end that interfaces with the composite pipe material and a second end that interfaces with the steel flange, thereby mediating the connection between two incompatible materials with different structural properties and thermal expansion characteristics.
Solution Approach 2:
The transition piece itself is constructed as a composite structure, combining materials that are compatible with both the composite pipe and the steel flange. This allows the transition piece to bridge the gap between the two different material systems, providing a reliable connection while maintaining the benefits of composite pipe material.
2Strength
If different structural properties and thermal expansion differences exist between composite pipe and steel flange, then material performance is improved, but structural and sealing connection reliability deteriorates
Solution Approach 1:
The transition piece is designed with specific geometric parameters and material properties that accommodate the different thermal expansion rates of composite pipe and steel flange. By carefully selecting the length, thickness, and material composition of the transition piece, the connection can withstand thermal cycling without compromising structural or sealing integrity.
3Weight of moving object
If composite pipe with low specific gravity is used, then weight and resistance to aggressive environments is improved, but buoyancy control and stability on sea floor deteriorates
Solution Approach 1:
An armouring layer is applied locally to specific sections of the composite pipe, particularly at the ends and burial zones, to increase specific gravity where needed. The armouring layer consists of wire mesh or spiral-wound steel elements that provide additional weight and stability without compromising the overall lightweight and corrosion-resistant properties of the composite pipe material.
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 provides a reliable and stable termination of composite pipes, ensuring sealing engagement and structural integrity, even in harsh subsea conditions, by compressing the liner extension piece into the annular transition element, effectively addressing the challenges of buoyancy and instability.
Implementation Method 1
compression means; whereby the compression means compresses the extension piece into sealing engagement with the exterior surface of the annular transition element
Data Source
AI summary
An apparatus for terminating a composite pipe has a pipe having a liner layer surrounded by a composite layer and a pipe end. The liner layer has an extension piece which extends axially beyond the composite layer at the pipe end; a connector; an annular transition element located between the pipe end and the connector, the annular transition element having an exterior surface; and compression means.