Pipe Repair Liner Expansion Sleeve for Air Pocket Relief
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Solution Overview
Problem
Existing pipeline repair methods face issues with fluid or air getting stuck between the liner and the pipe wall, especially at bends or elbows, leading to air pockets and reduced internal diameter, causing flow problems and restrictions.
Innovation Solution
A sleeve with a relief area of reduced modulus of elasticity is used between the bladder and the liner, allowing controlled expansion by positioning the relief area at specific locations, such as bends, to prevent air pockets and ensure full expansion of the liner against the pipe wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bladder fully inflates to press the liner against the pipe wall, then the liner adheres to the pipe surface, but air pockets become trapped at bends or elbows causing flow restrictions
Solution Approach 1:
The sleeve is segmented into different regions with different modulus of elasticity - a first portion with higher modulus and a second portion with lower modulus. This segmentation allows the sleeve to expand differently in different regions, enabling air to escape from trapped pockets while maintaining liner adhesion in critical areas.
Solution Approach 2:
The sleeve has non-uniform mechanical properties with different portions having different modulus of elasticity. The lower modulus portion is strategically positioned to allow localized expansion that facilitates air pocket elimination, while other portions maintain higher stiffness for proper liner support and adhesion.
2Device complexity
If a uniform modulus sleeve is used, then the structure is simple, but the liner cannot expand uniformly causing air pockets at bends
Solution Approach 1:
Instead of a uniform structure, the sleeve incorporates regions with different modulus of elasticity. This local variation in material properties enables differential expansion behavior that achieves uniform liner contact with the pipe wall, particularly at bends and elbows where uniform expansion would be impossible with a homogeneous sleeve.
3Strength
If the sleeve expands with high pressure, then the liner is firmly pressed against the pipe wall, but air pockets are trapped and cannot escape
Solution Approach 1:
The sleeve is divided into portions with different mechanical properties. The lower modulus portion acts as an expansion joint that allows the liner to expand outward and upward, creating a path for trapped air to escape, while the higher modulus portions maintain sufficient press force to ensure proper liner adhesion.
Solution Approach 2:
The sleeve with varying modulus acts as an intermediary between the bladder and the liner. It translates the uniform pressure from the bladder into differential expansion patterns that facilitate air pocket elimination while maintaining the necessary contact force between the liner and pipe wall.
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 controlled expansion of the sleeve and liner assembly minimizes air pockets, maintains the internal diameter, and ensures effective repair by allowing fluid to escape, preventing flow restrictions and ensuring proper lining at bends and curves.
Implementation Method 1
The relief area has a second modulus of elasticity that is less than the first modulus of elasticity. The reduced modulus of elasticity of the relief area allows the sleeve to expand outward with less pressure.
Implementation Method 2
upon the introduction of fluid pressure into the bladder, the bladder, sleeve, and liner expand outward at the relief area first. Then, as pressure inside the bladder increases, the remainder of the assembly is expanded.
Data Source
AI summary
An assembly and method for repairing a pipeline. The assembly may include a sleeve positioned between a bladder and a liner. The sleeve includes a relief area having a reduced modulus of elasticity. The reduced modulus of elasticity at the relief area allows the sleeve to expand outward with less pressure. Upon the introduction of fluid pressure into the bladder, the bladder, sleeve, and liner expand outward at the relief area first. Then, as pressure inside the bladder increases, the remainder of the assembly is expanded. In this manner the user can control which area of the assembly is expanded first by positioning the relief area at the appropriate location. In another embodiment a semi-rigid member is wound around the outside of the liner in a helical configuration to provide a pathway for trapped air to escape during inflation of the bladder and curing of the liner.