Bent Metal Pipe Inner Surface Geometry for Wrinkle Control

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Solution Overview

Problem

Metal pipes with curved portions often develop wrinkles and undulations on the inner surface, leading to fluid stagnation and increased resistance, which can cause corrosion, and existing methods using wipers are inefficient and costly, especially for pipes with small radii of curvature.

Innovation Solution

A pipe manufacturing method involving a die with circular arc-shaped apices that form bent portions and non-bending surfaces, where the wall thickness at non-bending surfaces is greater than at bent portions, forming a regular polygon pattern to absorb wrinkles and prevent undulations, allowing for efficient bending without a wiper and reducing fluid resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a wiper is interposed between the die and the pipe to smooth wrinkles, then the appearance is improved, but the manufacturing cost increases and efficiency decreases

Engineering Contradiction:
Improvesurface qualityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention removes the wiper component from the bending system entirely. Instead of using a wiper to smooth wrinkles, the patent creates controlled bent portions that actively absorb wrinkles during the bending process itself, eliminating the need for post-processing or additional components

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the harmful effect of wrinkles into a beneficial feature by designing bent portions that intentionally create controlled undulations. These controlled bent portions absorb the compressive forces that would otherwise create unwanted wrinkles, transforming a defect into a functional feature

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Manufacturing precision

If a wiper is used to reduce wrinkles, then the appearance improves, but the manufacturing cost increases due to consumable items

Engineering Contradiction:
Improvesurface qualityVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention eliminates the wiper component entirely from the manufacturing process. By designing the die to create controlled bent portions that absorb wrinkles during bending, the system removes the need for expensive consumable wipers and their associated replacement costs

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bending process itself becomes self-correcting for surface quality issues. The controlled bent portions automatically absorb wrinkles as the pipe is bent, making the system self-sufficient without requiring additional components or post-processing operations

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the pipe is bent to form a curved portion with small radius of curvature, then the design flexibility improves, but wrinkles are more likely to occur on the inside circumferential surface

Engineering Contradiction:
Improvedesign flexibilityVSAvoidsurface quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention divides the inner circumferential surface into multiple segments: controlled bent portions that absorb wrinkles and non-bending surfaces that maintain smooth appearance. This segmentation allows the pipe to achieve small radius of curvature while maintaining surface quality through the distributed wrinkle-absorbing bent portions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies different surface characteristics to different locations: bent portions with wrinkle-absorbing capability are strategically placed where compressive forces are highest, while non-bending surfaces maintain smooth appearance. This localized quality distribution optimizes both small radius capability and surface quality

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If regular undulations are formed to give good appearance, then the wiper can be taken out of use, but fluid stagnation and resistance may occur on the inner surface

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidfluid resistance
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention creates localized bent portions with specific geometric characteristics that differ from conventional undulations. These bent portions are designed with controlled depth and spacing to absorb wrinkles without creating significant protrusions into the fluid flow path, minimizing fluid resistance while maintaining manufacturing simplicity

Inventive Principle:
Principle #3Local quality

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 produces pipes with a smooth appearance, reduced fluid stagnation, and minimized resistance on the inner surface, enabling the manufacture of pipes with small radii of curvature without the need for wipers, thereby improving both aesthetics and functionality.

Implementation Method 1

a die with circular arc-shaped apices configured to abut on the unprocessed pipe to form a plurality of bent portions when the bending processing is performed

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3246103B1Pipe, die, and method for manufacturing pipe
Publication Date: 2022.01.19 SANOH IND CO LTD
  • EP3246103B1 patent drawingFigure 1
  • EP3246103B1 patent drawingFigure 2
  • EP3246103B1 patent drawingFigure 3(a)~3(b)

AI summary

A metal pipe including a curved portion produced by bending in which a plurality of non-bending surfaces and a plurality of bent portions at which the non-bending surfaces are connected in a bending manner are provided on a circumferential surface on an inside being a curvature center side of the curved portion. With this pipe, a good appearance can be maintained, and stagnation and resistance of a flow of a fluid can be reduced on the inner surface side of the pipe where the fluid flows.