Stainless Steel Corrugated Pipe for Drinking Water

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Solution Overview

Problem

Current corrugated pipes with a nominal diameter of DN 30 fail to meet the stringent requirements of flexural strength and pressure surge resistance as per the W/TPW 119/1 regulations, necessitating a complex and time-consuming experimental approach to find suitable parameter combinations, which is costly and inefficient.

Innovation Solution

A corrugated pipe with a nominal diameter of DN 30 made from longitudinally welded stainless steel strip material, with specific dimensions and corrugation parameters, including an inner diameter of 29.5 mm ± 0.5 mm, outer diameter of 34.6 mm ± 0.5 mm, and an average corrugation spacing of 5.1 mm ± 0.5 mm, optimized for both flexural strength and pressure surge behavior, ensuring compliance with the regulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the corrugated pipe is made more rigid to improve pressure surge resistance, then pressure surge behavior improves, but flexural strength decreases

Engineering Contradiction:
Improvepressure surge resistanceVSAvoidflexural strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies parameter changes by systematically varying multiple geometric parameters including corrugation height (e1), corrugation spacing (lW), wall thickness (s), and diameters (d1, d2) to find the optimal combination that simultaneously satisfies both flexural strength and pressure surge resistance requirements. This multi-parameter optimization approach resolves the contradiction by finding a balanced configuration rather than maximizing one parameter at the expense of the other.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the corrugation height is increased to improve flexibility for pressure surge cushioning, then pressure surge behavior improves, but flexural strength decreases

Engineering Contradiction:
Improvepressure surge cycle resistanceVSAvoidflexural strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent specifically optimizes the corrugation height parameter (e1) within a defined range to achieve the desired balance. By controlling this geometric parameter along with others, the design achieves sufficient flexibility for pressure surge absorption while maintaining adequate flexural strength to pass the bending test requirements.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the corrugation spacing is decreased to improve flexibility, then pressure surge behavior improves, but manufacturing complexity increases

Engineering Contradiction:
Improvepressure surge resistanceVSAvoidcorrugation geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent optimizes the corrugation spacing parameter (lW) to achieve the right balance between flexibility and manufacturability. The selected parameter range provides sufficient flexibility for pressure surge resistance while remaining within practical manufacturing capabilities for forming the corrugations.

Inventive Principle:
Principle #35Parameter changes

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 optimized corrugated pipe successfully passes the flexural strength and pressure surge tests, meeting the W/TPW 119/1 requirements, and demonstrates improved performance in heat transfer applications with minimal plastic deformation under pressure.

Implementation Method 1

The corrugated structure ensures that the corrugated pipe has a large surface area and thus good heat exchange on the pipe wall

Methodology Applied
Scientific EffectHeat exchange: Conduction (thermal)

Data Source

PatentEP2960564B1Corrugated tube for a drinking water installation
Publication Date: 2019.07.24 WITZENMANN GMBH
  • EP2960564B1 patent drawingFigure 1~2

AI summary

The present invention relates to a ring-corrugated pipe (2) made of stainless steel suitable for drinking water for installation in a drinking water installation, in particular a stratified storage tank, which is characterized in that the corrugated pipe is made of longitudinally welded strip material of a thickness in the range of 0.3 mm ± 0.015 mm and has a corrugation whose corrugations have an inner diameter (d1) in the range of 29.5 mm ± 0.5 mm and an outer diameter (d2) in the range of 34.6 mm ± 0.5 mm.