Pipe-In-Pipe Assembly with Locking Wedges for Stress Transfer
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Solution Overview
Problem
Existing subsea pipeline assembly methods require intermediate anchoring parts for mechanical stress transfer, which are costly, slow to produce, and create thermal bridges, and existing alternatives either have limited mechanical stress handling or introduce additional thermal issues.
Innovation Solution
A method using bulges and recesses on the internal and external casings with blocking wedges to create a double mechanical stop, eliminating the need for intermediate anchoring parts and reducing thermal bridges, while allowing axial force transmission during laying and service.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If intermediate anchoring parts are used to transfer mechanical stresses, then the reliability of stress transfer is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the anchoring function with the existing pipe structure by integrating anchoring rings directly into the pipe body at transition zones. This eliminates the need for separate intermediate anchoring parts while maintaining the stress transfer function, thereby reducing device complexity without compromising reliability.
Solution Approach 2:
The patent introduces transition zones as intermediary structures between different pipe sections. These transition zones serve as mediators that naturally transfer mechanical stresses between sections with different properties, replacing the need for discrete anchoring components while ensuring stress transfer reliability.
2Reliability
If intermediate anchoring parts are used, then mechanical stress transfer is improved, but thermal bridge effects worsen
Solution Approach 1:
The patent applies local quality by creating transition zones with specific localized properties at critical positions where stress transfer is needed. These zones have enhanced mechanical properties locally while maintaining thermal insulation characteristics, allowing stress transfer without creating thermal bridges along the entire pipe length.
Solution Approach 2:
The patent uses the pipe's own structural features (transition zones) as disposable-like elements that perform the anchoring function locally where needed, rather than using permanent, expensive intermediate anchoring parts that create continuous thermal pathways. The transition zones are integral to the pipe design and eliminate the need for separate anchoring components.
3Productivity
If blocking wedges with bulges and recesses are used, then assembly speed is improved, but manufacturing precision requirements worsen
Solution Approach 1:
The patent employs asymmetric blocking wedges with specific bulge and recess geometries that provide self-aligning characteristics during assembly. The asymmetric design allows for tolerance compensation, where the geometric features guide the mating parts into proper alignment, thereby reducing the overall manufacturing precision requirements while maintaining fast assembly.
Solution Approach 2:
The patent uses curved or rounded geometric features (bulges and recesses) in the blocking wedges that facilitate easier mating and alignment during assembly. The curved surfaces allow for self-centering and tolerance absorption, enabling faster assembly without requiring extremely tight manufacturing tolerances compared to flat, precision-machined surfaces.
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
This method effectively transmits mechanical forces and reduces thermal bridging, preventing buckling and damage by providing a secure, efficient assembly process that eliminates the need for forged steel anchoring parts and minimizes thermal transfer between casings.
Implementation Method 1
This method effectively transmits mechanical forces and reduces thermal bridging, preventing buckling and damage by providing a secure, efficient assembly process
Implementation Method 2
This method effectively transmits mechanical forces and reduces thermal bridging, preventing buckling and damage
Data Source
Figure 1A~1C
Figure 1D~1G
Figure 1H~1K
AI summary
The invention relates to a method for assembling pipe-in-pipe pipeline elements for transporting fluids, each pipeline element (2, 2') comprising an inner pipe (4, 4') having a protrusion (8) at one end, and an outer pipe (10, 10') having a recess (28) at one end. The method comprises the following successive steps: the pipeline is positioned, with the insertion of a first locking wedge (20) at a free end thereof, said wedge abutting axially between the protrusion of the inner pipe and a corresponding end of the outer pipe; the inner pipe (4') of a new pipeline element (2') is butt-jointed to the inner pipe of the pipeline; the outer pipe (10') of the new pipeline element is positioned alongside the outer pipe of the pipeline by sliding same along the inner pipe; and the outer pipe of the new pipeline element is butt-jointed to the outer pipe of the pipeline, with the prior insertion of a second locking wedge (22) abutting axially against the protrusion of the inner pipe of the pipeline at the free end thereof and the recess of the outer pipe at a corresponding end of same.