Double-Walled Pipe Bonding for Reelable Welded Ends
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Solution Overview
Problem
Existing methods for producing double-walled pipes fail to ensure defect-free welding and mechanical stability, particularly when using the reeling method, due to the risk of the inner pipe detaching from the outer pipe or creasing during unrolling, which can lead to inclusions, voids, or pores in the weld-plated layer, impairing durability and stability.
Innovation Solution
A method involving adhesive bonding between the outer and inner pipes, followed by removal of the inner pipe and adhesive layer at the pipe ends, allowing for high-quality weld-plating that creates a material-bonded connection, preventing creasing and ensuring mechanical stability, and enabling the production of long, reelable pipes with protected ends against corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is introduced between the outer pipe and inner pipe to prevent detachment during reeling, then the reliability of the pipe connection is improved, but the manufacturing precision of weld-plating deteriorates due to adhesive residue causing inclusions, voids or pores
Solution Approach 1:
The pipe is divided into two distinct zones: the middle section where adhesive bonding occurs to prevent creasing during reeling, and the end sections where adhesive is removed to enable high-quality weld-plating. This spatial segmentation allows both adhesive bonding and defect-free welding to coexist in different regions of the same pipe.
Solution Approach 2:
The adhesive layer is selectively removed from the end regions of the pipe where welding is required. This extraction of the adhesive from specific zones eliminates the source of contamination (inclusions, voids, pores) while preserving the adhesive bonding in the middle section where it prevents creasing during reeling operations.
2Ease of manufacture
If the inner pipe is pressed into the outer pipe using hydraulic expansion, then the ease of manufacture is improved, but the strength of the connection deteriorates due to potential detachment during reeling
Solution Approach 1:
The patent combines two joining methods: hydraulic expansion for initial connection and adhesive bonding for reinforcement. The hydraulic expansion process easily joins the pipes mechanically, while the adhesive layer adds supplemental bonding strength to prevent detachment during reeling, creating a hybrid connection that leverages the advantages of both methods.
Solution Approach 2:
The connection between inner and outer pipes becomes a composite structure combining mechanical interlocking (from hydraulic expansion) and chemical bonding (from adhesive). This composite joining approach creates a multi-mechanism connection that is both easy to manufacture and strong enough to withstand reeling operations.
3Reliability
If adhesive bonding is used throughout the entire pipe length to prevent creasing, then the reliability during reeling is improved, but the ease of operation for welding deteriorates due to adhesive interference at pipe ends
Solution Approach 1:
The pipe is divided into two distinct zones: the middle section where adhesive bonding occurs to prevent creasing during reeling, and the end sections where adhesive is removed to enable high-quality weld-plating. This spatial segmentation allows both adhesive bonding and defect-free welding to coexist in different regions of the same pipe.
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 method ensures a mechanically stable pipe end that can be easily connected, preventing creasing and corrosion, and allows for defect-free welding, enhancing the durability and quality of the double-walled pipes by maintaining a stable connection between the inner and outer pipes.
Implementation Method 1
an adhesive is introduced at least in certain regions between the outer pipe and the inner pipe
Implementation Method 2
the inside of the outer pipe is plated forming a material-bonded connection with the inner pipe
Implementation Method 3
The essential feature in the production of pipes of this kind is a hydraulic three-dimensional expansion process of an inner pipe
Implementation Method 4
The adhesive layer effectively avoids creasing of the inner pipe or liner during rolling and unrolling of the pipe strand
Data Source
AI summary
The application relates to a method for producing a double-walled pipe (1) and a pipe (1) of this type, having an outer pipe (3) which is press-fitted with an inner pipe (2) consisting of a corrosion-resistant alloy, wherein an adhesive (4) is inserted at least in regions between the outer pipe (3) and the inner pipe (2), wherein, after adhering the inner pipe (2) with the outer pipe (3), the inner pipe (2) and the adhesive layer (4) are removed at the pipe ends, and the inner side of the outer pipe (3) is plated via an integral connection with the inner pipe (2).