Cross-Wound Composite Pipe Coating for Trenchless Laying
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Solution Overview
Problem
Existing buried steel pipes with thin polypropylene, polyethylene, or polyurethane coatings suffer from low mechanical strength and poor adhesion, leading to mechanical damage during trenchless pipe-laying processes, which compromises corrosion protection.
Innovation Solution
A metal pipe with a thermoplastic casing surface and a glass-fibre-reinforced thermo-setting coating, applied using a wet-on-wet method with cross-wound glass fibres and a resin matrix, providing enhanced mechanical strength and directional protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin thermoplastic coating (polypropylene, polyethylene, or polyurethane) is applied to metal pipes, then corrosion protection is provided, but mechanical strength and adhesion are insufficient leading to damage during installation
Solution Approach 1:
The patent applies a multi-layer composite coating system consisting of a thermoplastic base layer (polypropylene, polyethylene, or polyurethane) for corrosion protection, followed by a thermosetting coating layer (epoxy, polyester, or vinyl ester resin) reinforced with glass fibres. This composite structure combines the corrosion-resistant properties of thermoplastics with the high mechanical strength and adhesion of thermosetting glass-fibre-reinforced plastics, resolving the contradiction between corrosion protection and mechanical strength.
2Strength
If a fibre cement casing is added to protect the thermoplastic coating, then mechanical protection is improved, but adhesion remains poor due to low adhesive power of thermoplastic materials
Solution Approach 1:
The patent uses the thermosetting resin (epoxy, polyester, or vinyl ester) as an intermediary material between the thermoplastic base layer and the glass fibre reinforcement. This intermediary provides excellent adhesion to the thermoplastic surface while simultaneously providing the mechanical strength and structural integrity of the glass fibre reinforcement, eliminating the adhesion problems associated with fibre cement casings.
3Ease of manufacture
If glass fibres are wound in a single direction on the pipe, then application is simplified, but the pipe can only be advanced in one direction without increased damage risk
Solution Approach 1:
The patent employs an asymmetric winding pattern where glass fibre bands are applied at specific angles (e.g., 45 degrees) in alternating directions around the pipe circumference. This asymmetric arrangement creates balanced mechanical properties in all directions, allowing the pipe to be advanced in any direction during installation without concentrating stress or damage risk in a single direction, while still maintaining relatively simple application procedures.
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 enhances the mechanical strength and adhesion of the coating, reducing damage during pipe-laying and maintaining effective corrosion protection, allowing pipes to be advanced in any direction with improved stability and reduced risk of damage.
Implementation Method 1
The layers are applied to the thermoplastic casing surface using a vinyl ester, polyester, or epoxy resin in a wet-on-wet method
Implementation Method 2
a glass-fibre-reinforced thermo-setting coating surrounding the thermoplastic casing surface. The thermo-setting coating consists of multiple layers of glass-fibre-reinforced plastic (GfK)
Implementation Method 3
Cross-wound means that the glass fibres are applied to the pipe by winding, whereby one (glass) layer is applied in a first winding direction and a second (glass) layer is applied in the opposite direction to this winding direction
Data Source
AI summary
The invention relates to a pipe having a thermoplastic casing surface a glass-fibre-reinforced thermo-setting coating surrounding the thermoplastic casing surface. The thermo-setting coating 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 a wet-on-wet method using a vinylester, polyester or epoxy resin. According to the invention, an outer layer of the thermo-setting coating is formed from cross-wound glass-fibre fleece or glass-fibre fabric.