Stretchable Pipe Liner Structure for High Burst Strength
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Solution Overview
Problem
Conventional cured-in-place pipe liners with random-oriented chopped glass fiber fabrics lack maximized strength characteristics, particularly under pressure, due to their loose fiber orientation, which affects their performance in high-pressure fluid applications like sewer and water pipes.
Innovation Solution
A cured-in-place pipe liner comprising a sheet of liner material with a strength layer of longitudinally oriented chopped fibers secured to a felt backing layer, configured into a tube shape and impregnated with a curable polymer, allowing for radial stretching and forming a strong, watertight barrier with a burst strength of at least 600 psi when cured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If random-oriented chopped glass fiber fabric is used, then the fabric can stretch during installation to prevent wrinkles, but the strength characteristics are not maximized for pressure pipe lining applications
Solution Approach 1:
The patent applies local quality by orienting chopped fibers in specific directions (circumferential and longitudinal) rather than randomly throughout the fabric. This creates regions with different fiber orientations that provide both stretchability in certain directions and maximized strength in others, particularly in the hoop direction for pressure resistance
Solution Approach 2:
The patent uses composite materials by combining chopped glass fibers with a polymer resin matrix to form a fabric structure. This composite construction allows the fibers to be oriented in specific patterns while the resin binds them together, achieving both the desired stretchability and strength characteristics that neither material could provide alone
2Strength
If continuous fiber fabric is used, then the strength characteristics are maximized, but the fabric is less stretchable during installation
Solution Approach 1:
The patent applies segmentation by using chopped fibers (short segments) rather than continuous fibers. This segmentation allows the fiber ends to move and reorient more freely during stretching, providing the necessary stretchability for installation while still maintaining high strength characteristics when the fibers are oriented in specific directions and bound by the polymer matrix
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 a high-strength, watertight liner that effectively resists bursting under internal pressure, maintaining structural integrity and preventing wrinkles during installation, making it suitable for high-pressure fluid applications.
Implementation Method 1
The liner tube is configured for being impregnated with a curable polymer and stretched radially from the first external diameter to a second external diameter larger than the first external diameter
Implementation Method 2
The liner tube is configured for being impregnated with a curable polymer and stretched radially from the first external diameter to a second external diameter larger than the first external diameter
Data Source
AI summary
A liner tube for lining a pipe and pipe lining method. Liner material that includes a strength layer and felt backing layer forms the liner tube. The strength layer includes chopped strands of fiber oriented generally parallel to one another and distributed along the strength layer. The felt backing layer can be needle punched to the strength layer. Joining structure can connect opposite longitudinal edge margins of the liner material to form a tube shape. The liner tube is impregnated with a curable polymer, positioned in the pipe, and cured to form the liner. The liner stretches radially when it is positioned in the pipe. As the liner stretches, the strength layer remains fixed to the felt backing and the width of the overlapping edge margins does not decrease.