Stepped Composite Pipe End-Fitting for Sealed Steel Transitions
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Solution Overview
Problem
The challenge lies in effectively terminating composite pipes, particularly those made of fibre-reinforced thermoplastic polymer, to non-composite steel piping and apparatus, ensuring a reliable structural and sealing connection while withstanding axial and torsional forces, and maintaining a small diameter.
Innovation Solution
A composite pipe termination design featuring a composite pipe with a fused liner, an annular portion with stepped regions, an annular collar with matching stepped portions, and locking means to prevent axial movement, along with sealing elements and threaded connections to secure the end-fitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a steel end-fitting is attached to a composite pipe, then a structural connection is achieved, but the different structural properties and thermal expansion differences create challenges for reliable structural and sealing connection
Solution Approach 1:
The end-fitting is divided into multiple functional segments: a metal portion for structural strength and connection to steel piping, a polymer portion for sealing and thermal expansion accommodation, and an intermediate region for stress distribution. This segmentation allows each portion to address specific requirements without compromising the others.
Solution Approach 2:
The end-fitting employs composite construction combining metal and polymer materials in a single integrated component. The metal portion provides structural strength while the polymer portion provides sealing capability and accommodates thermal expansion differences between composite pipe and steel piping.
2Reliability
If the pipe termination diameter is increased to accommodate connection features, then connection reliability improves, but the diameter becomes significantly larger than the pipe diameter
Solution Approach 1:
The end-fitting extends primarily in the axial direction rather than radially, with the metal portion forming a flange or hub structure that projects along the pipe axis. This dimensional orientation allows connection features to be developed in the axial dimension while maintaining a compact radial profile that matches the pipe outer diameter.
3Force
If locking means are added to prevent axial movement, then axial force resistance improves, but device complexity increases
Solution Approach 1:
The locking functionality is merged into the overall end-fitting structure rather than being a separate component. The metal portion's rigid structure and geometric features inherently provide axial load resistance and positioning, eliminating the need for additional dedicated locking mechanisms.
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 design provides a reliable, sealed connection that withstands high pressure and temperature, distributes stress, and maintains a compact size, enhancing the durability and integrity of composite-to-steel transitions.
Implementation Method 1
a liner, wherein the interior pipe surface is fused to the liner
Data Source
AI summary
A composite pipe termination that includes: a) a composite pipe having an interior pipe surface, an exterior pipe surface, a pipe end and a liner; b) an annular portion of composite material attached to the exterior pipe surface, the annular portion having a first stepped region in which the annular portion decreases in radial thickness in the axial direction away from the pipe end by at least one step; c) an annular collar enclosing the first stepped region; d) an end-fitting interfacing with the annular portion and locked to the annular collar. The annular collar has a stepped portion in which the annular collar increases in radial thickness in the axial direction away from the pipe end by the same number of steps as in the first stepped region. The steps of the stepped portion mate with steps of the first stepped region.