Textile Liner for Large-Diameter Pipe Repair
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Solution Overview
Problem
Current methods for repairing large-diameter pipes, such as caissons in the offshore oil and gas industry, face challenges due to corrosion issues with steel liners and limitations in manufacturing textile-based liners that can accommodate the required sizes and strengths for caisson repair, particularly in handling and inserting tubular layers of sufficient weight and size.
Innovation Solution
A textile liner material comprising four sheets of double-bed warp-knitted fabric, arranged into a tubular structure with longitudinally extending joins, using glass fibre yarn for strength and resilience, and a method of bonding fabric layers to create a stable mesh-stabilised web for easier processing and expansion, allowing for resin infusion and curing to form a strong, corrosion-resistant composite.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel liner is used for caisson repair, then structural strength is improved, but corrosion resistance deteriorates due to galvanic corrosion in salt water environment
Solution Approach 1:
The patent uses a composite material system consisting of glass fibre reinforced plastic (GRP) liner combined with sacrificial anodes. The GRP liner provides structural strength while being inherently corrosion-resistant in salt water environments. The sacrificial anodes (zinc or aluminium) are electrically connected to the GRP liner to provide cathodic protection, creating a composite solution that addresses both strength and corrosion resistance requirements simultaneously.
2Adaptability or versatility
If multiple 3m liner segments are joined together to repair longer corroded sections, then repair coverage is improved, but liner strength deteriorates due to weak join points
Solution Approach 1:
The patent segments the liner installation into multiple 3m sections that are joined together using welding or mechanical coupling methods. Each section can be independently installed and secured to the caisson, allowing flexible adaptation to various repair lengths. The join points are designed to maintain structural integrity through proper welding techniques or mechanical fastening systems that distribute loads effectively.
Solution Approach 2:
The patent combines multiple liner sections into a continuous protective system through welding or mechanical coupling. The joined sections work together as an integrated structure, with the connections designed to transfer loads effectively between segments. This merging approach allows the system to achieve the required repair coverage while maintaining adequate structural strength across the entire liner assembly.
3Reliability
If textile liner is used instead of steel, then corrosion resistance is improved, but manufacturing difficulty increases due to handling and inserting large-diameter tubular layers
Solution Approach 1:
The patent employs flexible textile-based GRP liners that can be manufactured in large diameters and rolled into compact forms for easy transport and handling. The flexible nature of the textile reinforcement allows the liner to be inserted into the caisson and then expanded to fit the internal circumference. This flexibility dramatically simplifies the installation process compared to rigid alternatives while maintaining the corrosion-resistant properties of the textile composite material.
4Ease of operation
If liner length is limited to 3m for practical installation, then installation simplicity is improved, but repair effectiveness deteriorates for longer corroded sections requiring multiple joins
Solution Approach 1:
The patent adopts a segmented liner approach where the total liner length is divided into multiple 3m sections. Each section is independently manufactured and installed, maintaining the simplicity of handling short sections. The segments are joined using welding or mechanical coupling methods that create continuous protection along the entire corroded area. This segmentation strategy allows the system to effectively repair long corroded sections while preserving the installation advantages of shorter, more manageable components.
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 enables the production of a lightweight, flexible, and strong textile liner that can be easily transported and installed in caissons, overcoming the limitations of steel liners and existing textile liner manufacturing processes, providing effective corrosion resistance and structural integrity for large-diameter pipe repairs without the need for inserting multiple tubular layers.
Implementation Method 1
Cracks and holes therefore develop within a relatively short timescale, localised around the pump site... by electrical connection of the caisson to a sacrificial anode
Implementation Method 2
The resin is then cured, either by UV irradiation or otherwise, to give a strong, corrosion resistant structure
Implementation Method 3
A swaging tool then applies hydraulic pressure to a localised liner section above the damaged area, expanding it against the caisson and creating a permanent joint
Data Source
AI summary
A material for use in lining large-diameter pipes is disclosed. A textile material formed to a tubular shape and impregnated with resin may, on curing the resin, repair a damaged pipe in a cure in place pipe (CIPP) rehabilitation process. The present invention provides both a novel structure of tubular material and a novel method of preparing the material for use in a CIPP rehabilitation process, specifically aimed at large-diameter pipes such as oil rig caissons. The tubular material of this invention comprises four sheets of a double-bed warp-knitted fabric (40). A first pair of sheets (52) are arranged to form, respectively, inside and outside surfaces of a first half-tube, with fabric machine direction extending along the length of the half-tube. The second pair of sheets (52a) are similarly arranged to form a second half-tube. The two half-tubes are connected at a pair of longitudinally extending joins (58, 60). The preparation process includes stabilising tensioned sheets with a mesh layer (44), which makes for better handling of the knitted fabric.