Seamless Multilayer Composite Pipe Manufacturing Without Welding
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Solution Overview
Problem
Conventional methods for manufacturing multilayer composite pipes require complex machinery, skilled operators, and result in higher production costs due to the need for metal welding, leading to reduced strength and increased risk of welding failures under hydrostatic pressure.
Innovation Solution
A method and apparatus for manufacturing seamless multilayer composite pipes through co-extrusion of metal and plastic layers without welding, using a hot-extrusion die and co-extrusion head to apply layers directly onto the metal pipe, followed by cold working to reduce diameter and enhance adhesion, allowing for simpler processing and reduced costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to join metal layers, then strength and stability of the metal layer is ensured, but device complexity increases, production costs increase, and reliability decreases due to welding failures
Solution Approach 1:
The invention extracts and eliminates the welding process entirely from the manufacturing method. Instead of using TIG or laser welding to join metal layers, the patent applies metal foil or sheet directly to the plastic pipe using adhesive, completely removing the welding machinery and associated complexity while maintaining structural integrity through alternative bonding methods.
Solution Approach 2:
The invention introduces adhesive as an intermediary substance between the plastic pipe and metal layer, and between metal layers. This adhesive mediator enables layer bonding without requiring direct metal-to-metal welding, thereby eliminating welding complexity while achieving reliable structural connection and maintaining strength and stability.
2Reliability
If welding is used to join metal layers, then metal layers are connected, but reliability decreases due to welding failures and hidden defects under hydrostatic pressure
Solution Approach 1:
The invention extracts the welding process entirely, eliminating the source of welding failures and hidden defects. By replacing welding with adhesive bonding and mechanical attachment methods, the patent removes the reliability issues associated with weld quality control and hidden defects that compromise strength under hydrostatic pressure.
Solution Approach 2:
The invention uses adhesive layers as a consumable, non-critical bonding medium that can be easily applied and removed without affecting the fundamental strength of the metal layers. This approach replaces critical weld joints with a more forgiving bonding method that doesn't create permanent weak points under pressure.
3Strength
If transverse or oblique overlapping of aluminium sheet is used, then strength and stability are ensured, but loss of substance increases due to excessive metal use
Solution Approach 1:
The invention changes the application parameters of the metal layer by using adhesive bonding instead of overlapping or welding. This allows the metal foil or sheet to be applied in a single continuous layer without the need for transverse or oblique overlaps, thereby maintaining strength and stability while significantly reducing metal consumption and eliminating waste from excessive material use.
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 enables the production of pipes with improved strength and reduced manufacturing costs, eliminating the need for welding and allowing for flexible production of various sizes, with enhanced adhesion and pressure resistance due to the absence of weld lines.
Implementation Method 1
providing a seamless metal pipe with at least one continuous layer covering its inner surface by the further steps of adjusting a distance between a hot-extrusion die and a co-extrusion head in the direction of extrusion of the seamless metal pipe; feeding adhesive material through a channel and feeding material for the continuous layer to the co-extrusion head; co-extruding the adhesive material and the material for the continuous layer through the co-extrusion head onto the inner surface of the cooled seamless metal pipe
Implementation Method 2
passing the seamless metal pipe through a unit in order to reduce the diameter of the seamless metal pipe by cold working
Data Source
AI summary
The present invention relates to a method and an apparatus (100, 200) for manufacturing a seamless multilayer composite pipe (1), and a seamless multilayer composite pipe (1). The method of manufacturing a seamless multilayer composite pipe (1) comprises the steps of a) providing a seamless metal pipe (3) with at least one continuous layer (5) covering its inner surface, and b) passing the seamless metal pipe (3) through a unit (109, 209) in order to reduce the diameter of the seamless metal pipe (3) by cold working. The apparatus (100, 200) comprises said continuous layer (5) covering unit and said cold working unit (109, 209). A seamless multilayer composite pipe comprises a seamless metal pipe (3) with at least one continuous layer (5) covering its inner surface, wherein said continuous layer is mechanically compressed.