Cured-in-Place Liner Tube for Non-Excavation Pipe Repair
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Solution Overview
Problem
The high cost and time-consuming process of replacing aging underground pipes, such as sewers and storm drains, due to leaks caused by cracks and damage, necessitates an efficient and cost-effective solution for repairing pipes without excavation.
Innovation Solution
A cured-in-place tube liner system comprising flexible layers with porous intermediate materials and impermeable inner and outer layers, which can be inflated and cured in place within the existing pipe to create a gas/liquid-tight seal, using a method involving spools, folding mechanisms, and impregnation with a curable resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pipe replacement methods are used (excavation, removal, installation of new pipes), then reliable pipe replacement is achieved, but the process becomes extremely expensive and time-consuming
Solution Approach 1:
Instead of replacing the pipe from the outside by excavating and removing the old pipe, the invention inverts the approach by inserting a liner tube from the inside of the existing pipe. The liner is turned inside-out (inverted) and pressed against the inner walls, allowing repair without external access or excavation.
Solution Approach 2:
The liner tube is inserted within the existing damaged pipe, creating a nested structure where the new liner is placed inside the old pipe. This allows the repair mechanism to be contained within the existing infrastructure without requiring removal or external modification.
2Reliability
If traditional pipe replacement methods are used, then reliable pipe replacement is achieved, but the cost becomes extremely high due to heavy machinery and many workers
Solution Approach 1:
The invention inverts the traditional replacement approach by working from the inside out rather than outside in. This eliminates the need for expensive excavation equipment and large workforces, requiring only insertion and inflation equipment.
Solution Approach 2:
The liner is constructed as a flexible tube that can be easily inserted and deployed. The flexible nature of the liner allows it to be maneuvered through the existing pipe and expanded to fit, eliminating the need for heavy machinery and reducing labor requirements.
3Ease of operation
If a curable fabric liner is used to replace pipe from inside out, then excavation is avoided, but the liner must achieve sufficient rigidity to maintain structural integrity after curing
Solution Approach 1:
The liner material undergoes a parameter change from flexible to rigid through the curing process. The resin-impregnated fabric transitions from a pliable state during installation to a rigid, structurally sound state after curing, achieving both ease of insertion and structural strength.
Solution Approach 2:
The liner is constructed as a composite material combining fabric (for flexibility during installation) with curable resin (for structural strength after curing). This composite structure allows the liner to be easily inserted in a flexible state and then gain the necessary rigidity when the resin cures.
4Ease of operation
If the liner is made flexible for insertion, then ease of installation is improved, but the liner must expand to achieve a circular cross-section to fit the pipe properly
Solution Approach 1:
The liner transitions from a static, flexible state during insertion to a dynamic, expanded state during installation. The liner is inserted in a collapsed or flattened configuration and then expanded using fluid pressure to achieve the proper circular cross-section shape.
Solution Approach 2:
Fluid pressure (pneumatic or hydraulic) is used to expand the liner from its collapsed insertion state to its operational circular cross-section. The fluid medium applies pressure to force the liner against the pipe walls, achieving the required shape.
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 system allows for the repair of pipes without excavation, providing a durable, leak-proof inner lining that reduces installation costs and time, while withstanding axial forces and expanding to fit the pipe's shape, ensuring a secure fit and long-lasting solution.
Implementation Method 1
The liner tube includes an inner layer, an outer layer disposed around the inner layer, a first intermediate layer disposed between the inner layer and the outer layer... the first and second intermediate layers include porous material... impregnated with a curable resin
Implementation Method 2
Once the resin cures (due to a catalyst of heat, light, or chemical), the liner is rigid
Implementation Method 3
By using a fluid medium under pressure (e.g. gases or liquids, including air or water), the liner is pressed against the inner walls of the existing damaged pipe
Data Source
AI summary
A liner tube for repairing existing pipes is provided. The liner tube is sufficiently flexible to lie substantially flat under its own weight thereby defining an upper portion and a lower portion. The liner tube includes an inner layer, an outer layer disposed around the inner layer, a first intermediate layer disposed between the inner layer and the outer layer, the first intermediate layer being wrapped around the inner layer to overlap itself and define a first overlap portion in the upper portion, and a second intermediate layer disposed between the first intermediate layer and the outer layer, the second intermediate layer being wrapped around the first intermediate layer to overlap itself and define a second overlap portion in the lower portion. The first and second intermediate layers include a porous material and the inner layer includes material substantially impermeable to liquids.