Composite Pipe Wave Trough Design for Bubble-Free Sealing

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Solution Overview

Problem

In composite pipe manufacturing, especially for nominal widths DN ≤ 300, a bubble-free connection between the inner hose and outer hose at the transition from corrugated pipe to pipe socket is not consistently achieved due to insufficient pressure buildup, leading to defects like dents and improper sealing.

Innovation Solution

The relative lengthening of the wave trough preceding the pipe socket ensures a sufficient seal, allowing pressure to build up quickly within the inner hose, enabling it to firmly press against the outer hose, thereby achieving a bubble-free and defect-free connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If production speed is increased for smaller nominal widths (DN ≤ 300), then productivity is improved, but pressure buildup in the inner hose becomes insufficient, leading to connection defects

Engineering Contradiction:
Improveproduction speedVSAvoidconnection quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The wave trough is preliminarily designed with increased length (by 10-30% compared to other wave troughs) to create an extended sealing region before the pipe socket. This preliminary structural modification ensures that pressure can build up sufficiently within the inner hose during the high-speed production process, preventing pressure escape and ensuring reliable connection between inner and outer hoses without compromising productivity

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If pressure is applied to expand the inner hose against the outer hose, then connection quality is improved, but pressure escapes between the calibration mandrel and inner hose, causing dents and defects

Engineering Contradiction:
Improveconnection qualityVSAvoidpressure escape and dents
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The wave trough immediately preceding the pipe socket is locally modified with increased length (10-30% longer than other wave troughs). This local structural change creates an extended sealing zone that prevents pressure escape at this critical location, allowing pressure to be effectively applied to expand the inner hose against the outer hose without causing dents or connection defects

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

This solution ensures a reliable, bubble-free connection between the inner and outer hoses, preventing defects and ensuring a strong, sealed joint in the transition area.

Implementation Method 1

the inner hose is pressurized from the inside at the beginning of the expansion to the pipe socket

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

The relative lengthening of the first wave trough, which immediately precedes the pipe socket, ensures a sufficient seal between the inner hose and the calibrating mandrel

Methodology Applied
Scientific EffectSealing: Physical Containment

Data Source

PatentEP2436504B1Method for continuous manufacture of a connecting tube with rod fitting, connecting tube with rod fitting and device for executing the method and manufacturing the connecting tube
Publication Date: 2015.07.01 HEGLER RALPH PETER DR ING
  • EP2436504B1 patent drawingFigure 1
  • EP2436504B1 patent drawingFigure 2
  • EP2436504B1 patent drawingFigure 3

AI summary

A composite pipe (10) has an inner pipe (39') and an outer pipe (37'). The latter has a corrugation with crests (38) and troughs (40, 40'). The composite pipe (10) is further equipped with a pipe socket (41) which transitions into the composite pipe (10) via a transition section (61). The trough (40') immediately adjoining the transition section (61) has a width a that is greater than the width b of the other troughs (40).