Composite Pipe Structure for Trenchless Renovation Stability

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Solution Overview

Problem

Existing pipes used for liquid transport, particularly in landfills, face deformation and potential collapse due to mechanical stress, especially during trenchless renovation where lateral support is lacking, leading to instability and fluid removal issues.

Innovation Solution

A pipe design featuring a tubular body made of polyethylene with axially extending regions and radially circumferential recesses filled with fiber-reinforced composite material, providing mechanical stability and chemical resistance, allowing for trenchless renovation without lateral support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional pipe is used in trenchless renovation without lateral support, then the pipe can be inserted into old pipes, but the pipe deforms and collapses under mechanical stress from above

Engineering Contradiction:
Improvetrenchless renovation capabilityVSAvoidmechanical stability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The pipe combines polyethylene material with fiber-reinforced plastic (FRP) wrapping to create a composite structure. The polyethylene provides chemical resistance while the FRP layer provides enhanced mechanical strength and stiffness, enabling the pipe to withstand vertical loads without lateral support during trenchless renovation installations

Inventive Principle:
Principle #40Composite materials

2Strength

If a fiber-reinforced plastic pipe is used to increase mechanical stability, then the pipe resists deformation, but the pipe lacks chemical resistance to aggressive landfill leachate

Engineering Contradiction:
Improvemechanical stabilityVSAvoidchemical resistance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The pipe uses a composite structure where polyethylene material provides chemical resistance to landfill leachate while fiber-reinforced plastic wrapping provides mechanical stability. The two materials work together to simultaneously address both chemical and mechanical requirements that neither material could satisfy alone

Inventive Principle:
Principle #40Composite materials

3Strength

If the pipe wall thickness is increased to prevent deformation, then mechanical stability improves, but the pipe becomes more prone to fracture under point loads

Engineering Contradiction:
Improveresistance to deformationVSAvoidfracture resistance
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The fiber-reinforced plastic wrapping creates a composite structure that distributes point loads across the fiber network, preventing stress concentration that would lead to fracture. The fibers bridge cracks and distribute loads evenly, maintaining both deformation resistance and fracture toughness

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The fiber-reinforced plastic wrapping acts as a flexible reinforcement layer that can deform elastically under load and return to its original shape, providing toughness and fracture resistance while maintaining structural integrity under various loading conditions

Inventive Principle:
Principle #30Flexible shells and thin films

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 pipe maintains mechanical stability and chemical resistance, ensuring effective fluid transport and drainage, even in deformed or collapsing old pipes, by combining the strength of fiber-reinforced materials with the chemical resistance of polyethylene, thus preventing deformation and fracture.

Implementation Method 1

The second areas (7) are each a radially circumferential recess in the tubular body (3) between two first areas (5), the recess being at least partially filled with a second material (9) applied to the first material (1). The first material (1) is different from the second material (9), which is fiber reinforced.

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 2

The first material is different from the second material (9), which is fiber reinforced. The combination of the tubular body made of the first material with the fiber-reinforced second material (9) applied thereto in areas beyond the first areas (5) enables the combination of mechanical stability through the second material (9) with chemical resistance to the fluids transported in the tube

Methodology Applied
Scientific EffectChemical resistance:

Data Source

PatentEP3760415B1Pipe
Publication Date: 2023.12.13 FRIESS WALTER H
  • EP3760415B1 patent drawingFigure 1
  • EP3760415B1 patent drawingFigure 2
  • EP3760415B1 patent drawingFigure 3

AI summary

Pipe (1) with a pipe body (3) made of a first material, which has axially extending first regions (5) and at least one axially extending second region (7), wherein the second region (7) is a radially circumferential recess in the pipe body (3) between two first regions (5) which is at least partially filled with a second material (9), wherein the first material is different from the second material (9), which is fiber-reinforced.