Composite Pipe Coating for Corrosion and Trenchless Damage Resistance

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Solution Overview

Problem

Existing pipe coatings for underground and offshore applications suffer from low mechanical strength, poor adhesion, and mechanical damage during trenchless pipe-laying, compromising corrosion protection.

Innovation Solution

A metal pipe with a thermoplastic outer surface and a glass fiber-reinforced thermoset sheath, where the thermoset sheath is formed from multiple layers of glass fiber-reinforced plastic applied using a wet-on-wet process, with cross-wound outer layers and strategically designed thickness variations to enhance durability and ease of installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thin plastic coating (polypropylene, polyethylene, polyurethane) is applied to prevent corrosion, then corrosion protection is improved, but mechanical strength deteriorates

Engineering Contradiction:
Improvecorrosion protectionVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies a composite coating system consisting of an inner thermoplastic layer (polypropylene, polyethylene, or polyurethane) for corrosion protection and an outer fiber-reinforced thermoset layer (glass fiber, carbon fiber, or aramid fiber reinforced with epoxy or polyester resin) for mechanical strength. This composite structure combines the corrosion-resistant properties of plastics with the high strength of fiber-reinforced composites, resolving the contradiction between corrosion protection and mechanical strength.

Inventive Principle:
Principle #40Composite materials

2Strength

If fiber cement casing is applied to protect the plastic coating from mechanical abrasion, then mechanical protection is improved, but adhesion deteriorates

Engineering Contradiction:
Improvemechanical protectionVSAvoidadhesion
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces fiber cement with fiber-reinforced thermoset composite materials that provide both mechanical protection and adequate adhesion. The thermoset resin matrix bonds effectively to the thermoplastic layer while the fiber reinforcement provides the necessary mechanical strength and abrasion resistance, eliminating the adhesion problems associated with fiber cement.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If conventional single-direction winding is used for glass fiber application, then manufacturing simplicity is improved, but directional damage resistance deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddirectional damage resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent transitions from single-direction fiber winding to multi-directional winding patterns, including circumferential winding and longitudinal winding at various angles (such as 45 degrees). This multi-dimensional fiber arrangement distributes stresses from jackhammer impacts and other directional forces more effectively, preventing damage regardless of the direction of external forces while maintaining manufacturing feasibility through systematic winding procedures.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution provides enhanced mechanical strength and improved adhesion, allowing pipes to be driven in any direction without significant damage, facilitating trenchless installation and ensuring robust corrosion protection.

Implementation Method 1

a glass fiber-reinforced thermoset sheath enclosing the thermoplastic outer surface

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 2

the layers are applied to the thermoplastic outer surface using a wet-on-wet process using a vinyl ester, polyester, or epoxy resin

Methodology Applied
Scientific EffectResin saturation:

Implementation Method 3

at least the outer layer of the thermoset sheath is formed from cross-wound textile glass rovings or glass fiber mats or glass fiber fabrics

Methodology Applied
Scientific EffectFiber reinforcement:

Implementation Method 4

provide excellent corrosion protection, as soil moisture cannot come into contact with the metallic pipe material

Methodology Applied
Scientific EffectCorrosion barrier:

Data Source

PatentEP3814663B1Coated pipe and pipe combination
Publication Date: 2025.08.20 TDC INT AG
  • EP3814663B1 patent drawingFigure 1
  • EP3814663B1 patent drawingFigure 2
  • EP3814663B1 patent drawingFigure 3

AI summary

The invention relates to a pipe (100) having a thermoplastic casing surface (150) and a glass-fibre-reinforced thermo-setting coating (180) surrounding the thermoplastic casing surface (150). The thermo-setting coating (180) is formed from multiple layers of glass-fibre matting or glass-fibre fabric, or a combination of the two, wherein the layers are applied to the thermoplastic casing surface (150) in a wet-on-wet method using a vinylester, polyester or epoxy resin. According to the invention, an outer layer (186) of the thermo-setting coating (180) is formed from cross-wound glass-fibre fleece or glass-fibre fabric.