Double-Walled High-Pressure Pipe Drawing for Dynamic Load Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-pressure pipes used in dynamic pressure applications experience rapid wear and frequent replacement due to temporally and spatially varying pressure loads, which existing manufacturing methods fail to adequately address in terms of both pressure resistance and surface quality.
Innovation Solution
A method involving the creation of a double-walled tube through a non-positive connection between an inner and outer tube, achieved by drawing them together through a first drawing die, ensuring a stable and intact connection while maintaining high surface quality and sufficient wall thickness for enhanced pressure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wall thickness of the pipe is increased to improve pressure resistance, then the dynamic pressure resistance improves, but the manufacturing complexity and cost increase
Solution Approach 1:
The pipe wall is segmented into multiple layers (inner tube, outer tube, intermediate layer) with different materials and properties. This segmentation allows each layer to perform specific functions: the inner layer provides smooth surface quality, the intermediate layer provides ductility, and the outer layer provides strength, collectively achieving high dynamic pressure resistance without requiring excessive wall thickness
Solution Approach 2:
The invention uses composite material structure with at least three different materials in the wall cross-section. The composite structure combines materials with different properties (surface quality, ductility, strength) to optimize dynamic pressure resistance while controlling wall thickness and manufacturing complexity
2Productivity
If cold drawing with high deformation is used to reduce wall thickness, then manufacturing efficiency improves, but surface quality deteriorates
Solution Approach 1:
The inner tube is pre-formed with high surface quality through specialized processes (such as drawing over a polished mandrel or using a drawing die with appropriate surface treatment) before being combined with other layers. This preliminary action ensures the critical inner surface quality is established early, protecting it from degradation in subsequent manufacturing steps
Solution Approach 2:
Different regions of the pipe structure are given different qualities: the inner tube surface is optimized for smoothness and low roughness, while the outer tube and intermediate layer are optimized for mechanical properties. This local quality differentiation allows high surface quality in the critical inner region without compromising overall manufacturing efficiency
3Strength
If materials with high strength are selected to optimize pressure resistance, then the pressure resistance improves, but the ductility and crack propagation resistance may deteriorate
Solution Approach 1:
Different materials with different properties are assigned to different locations in the wall structure. The intermediate layer uses materials with high ductility and elongation to absorb energy and stop crack propagation, while the outer layer uses high-strength materials for pressure containment. This local quality differentiation optimizes both strength and crack resistance
Solution Approach 2:
The composite material structure combines materials with complementary properties: high-strength materials for pressure resistance, high-ductility materials for crack propagation resistance, and materials with appropriate surface quality for the inner tube. The synergistic combination achieves superior overall performance that cannot be obtained with a single 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 method provides a pipe with improved dynamic pressure resistance and extended service life by preventing crack propagation and maintaining high surface quality, suitable for pressures exceeding 12,000 bar.
Implementation Method 1
a non-positive connection of the outer tube with the inner tube is effected by drawing the inner tube and the outer tube together through a first drawing die
Implementation Method 2
the inner drawing tool or the rolling mandrel consists of steel with a polished surface, so that an inner lateral surface of the inner tube when the inner pipe is drawn over the inner drawing tool or during rolling over the rolling mandrel is burnished
Data Source
Figure 1a~1b
Figure 2~3
AI summary
The invention relates to a method for producing a high-pressure pipe (1). An inner pipe (2) made of metal and an outer pipe (3) made of metal are drawn together through a first drawing die (4a). The outer diameter (D2) of the inner pipe is smaller than the inner diameter (D3) of the outer pipe. By drawing the outer pipe and the inner pipe, which extends in the outer pipe, together through the first drawing die, a very stable force-fitting connection is produced between the inner pipe and the outer pipe. As a result, a pipe is produced with a large wall thickness, by means of which the produced pipe is very robust and pressure-resistant while having a very high quality outer lateral surface and in particular a very high quality inner lateral surface by virtue of the cold forming process. These two properties allow a sufficiently high protection of the pipe to be produced against bursting when pressures in excess of 12,000 bar are applied to the pipe. Accordingly, the method according to the invention is particularly suitable for producing a pipe with a clearly improved dynamic pressure resistance against high pressures by combining a large wall thickness of the pipe to be produced with a high quality inner lateral surface of the pipe to be produced.