Pipeline Liner Assembly With Non-Stretchable Strap
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Solution Overview
Problem
Conventional pipeline repair methods, such as push-in and pull-in delivery of resin-impregnated liners, face challenges like excessive friction causing liner stretching and rupture, especially in pipelines with bends and fittings, leading to weak repair sections and potential future failures, and prior art inflatable bladders are inadequate in accommodating various pipeline configurations.
Innovation Solution
A liner assembly featuring a malleable inflatable bladder with a non-stretchable strap to restrict longitudinal expansion and retaining sleeves to prevent radial over-expansion, allowing for smooth installation and curing within pipelines, including complex configurations like T-junctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional push-in or pull-in delivery methods are used to install resin-impregnated liners, then the liner can be delivered to the pipeline section, but excessive friction causes longitudinal stresses that stretch the liner, creating weak regions and increasing likelihood of future failure
Solution Approach 1:
The patent uses an inflatable bladder positioned within the liner that is inflated with fluid pressure to expand the liner into contact with the pipeline interior surface. This pneumatic/hydraulic mechanism eliminates the need for push-rods or cables that cause friction and stretching, allowing the liner to be delivered and installed without longitudinal stresses that would compromise its strength and reliability.
2Ease of operation
If conventional PVC/vinyl inflatable bladders are used to urge liners into contact with the pipeline inner surface, then the liner can be positioned, but the nonmalleable nature of these bladders introduces folds and creases in transitional areas
Solution Approach 1:
The patent changes the material parameter of the inflatable bladder from conventional rigid PVC/vinyl to a malleable material that can deform and conform to transitional areas such as bends and fittings in the pipeline. This parameter change allows the bladder to smoothly urge the liner into contact with the pipeline surface without introducing folds or creases, maintaining liner smoothness and preventing obstructions.
3Productivity
If inversion delivery methods are used with considerable pressures to unroll the liner, then the liner can be installed, but liner rupture is not uncommon, especially for longer liners
Solution Approach 1:
The patent replaces the inversion delivery method that uses considerable mechanical pressures with a pneumatic inflation method. The inflatable bladder is inflated with controlled fluid pressure to expand the liner gradually into the pipeline, eliminating the risk of liner rupture associated with high-pressure mechanical unrolling. This allows safe installation of longer liners without compromising integrity.
4Ease of operation
If the malleable inflatable bladder is allowed to expand freely during inflation, then the liner can be inflated to contact the pipeline surface, but longitudinal over-expansion stretches the liner creating weak regions
Solution Approach 1:
The patent applies preliminary anti-action by positioning a non-stretchable strap within the inflatable bladder before inflation. This strap restricts longitudinal expansion of the bladder during inflation, preventing the liner from being stretched and creating weak regions. The strap counteracts the tendency of the bladder to expand longitudinally, ensuring that inflation pressure is directed radially outward to contact the pipeline surface without compromising liner strength.
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 ensures minimal liner stretching and creasing, maintaining fluid flow and reducing the likelihood of future failures by providing a robust and evenly contacted resin-impregnated liner, effectively addressing the limitations of existing methods.
Implementation Method 1
introducing fluid into said malleable inflatable bladder so that said malleable inflatable bladder expands
Implementation Method 2
a generally non-stretchable strap positioned longitudinally within the malleable inflatable bladder, said strap restricting longitudinal over-expansion during positioning and inflation
Implementation Method 3
maintaining said liner assembly in an inflated condition for a time period sufficient for the outer felt liner tube to cure
Data Source
Figure 1
Figure 2~3
Figure 4a~4b
AI summary
A liner assembly (10) for pipeline repair and methods of installing same as described. The liner assembly (10) generally comprises an outer tubular liner (22), an inner malleable inflatable bladder (24) positioned longitudinally within the liner (22), and a generally non-stretchable strap (26) positioned longitudinally within the malleable inflatable bladder (24). The generally non-stretchable strap (26) restricts longitudinal over-expansion during positioning and inflation of the liner assembly (10) within a pipeline.