In-Situ Pipeline Replacement Using Expanded HDPE Liner
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Solution Overview
Problem
Current methods for replacing or rehabilitating pressurized pipelines, such as those for drinking water, natural gas, and sewerage, are costly and inefficient, particularly in urban areas where space is limited and buried infrastructure is dense, as they often require excavation or rely on the existing pipe for structural integrity and fitting attachment.
Innovation Solution
The method involves installing a deformed polymer pipe, like high-density polyethylene (HDPE), which expands to occupy up to 100% of the existing pipe's interior diameter, allowing for the creation of a new, independent pipeline system with standard, off-the-shelf fittings attached via heat fusion, eliminating reliance on the old pipe for structural support and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional excavation methods are used to replace pipelines, then the new pipeline can be installed with standard fittings, but the cost and time for installation increase significantly
Solution Approach 1:
The new polymer pipe is inserted inside the existing old pipe, with the expanded diameter of the new pipe occupying up to 100% of the interior diameter of the old pipe. This nesting approach allows installation without excavation while maintaining structural integrity and fitting reliability.
2Ease of manufacture
If the existing pipe is used for structural support and fitting attachment, then installation is simpler, but the new pipeline does not achieve full structural independence
Solution Approach 1:
The new pipe is expanded from a deformed state to its final expanded diameter within the old pipe, transforming it from a flexible insert to a structurally independent pipeline that occupies up to 100% of the old pipe's interior diameter. This parameter change enables the new pipe to bear full structural loads independently.
3Reliability
If a liner is used to rehabilitate pipelines, then ground water infiltration is reduced, but the pipeline capacity is reduced due to smaller interior diameter
Solution Approach 1:
Instead of inserting a smaller liner that reduces capacity, the invention inserts a new pipe that expands to occupy up to 100% of the old pipe's interior diameter. This inverted approach maintains full pipeline capacity while achieving the sealing effect of a liner.
4Manufacturing precision
If excavation is performed to replace pipelines in urban areas, then the new pipeline can be installed with proper alignment, but the cost and disruption increase due to limited space and dense infrastructure
Solution Approach 1:
The new pipe is deformed into a compact configuration before insertion, allowing it to be fed through the old pipe without excavation. After insertion, the pipe is expanded to its final diameter and shape, achieving proper alignment and configuration without the need for costly urban excavation.
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
This approach reduces costs by approximately one-third compared to traditional methods, increases pipeline capacity due to smoother interiors, and ensures a new pipeline with higher flow rates and pressure ratings, while minimizing excavation and reliance on the old pipe's alignment.
Implementation Method 1
a deformed polymer pipe, like high-density polyethylene (HDPE), which expands to occupy up to 100% of the existing pipe's interior diameter
Implementation Method 2
standard, off-the-shelf fittings attached via heat fusion
Data Source
AI summary
A method of in-situ pipeline replacement in which valves, fittings, and other obstructions are removed from an existing pipeline, a heat-fusible polymer pipeline having an initially deformed configuration less than the existing pipeline diameter is inserted into the remaining portions of the existing pipeline and reformed to substantially conform to the inside diameter of the existing pipeline, heat-fusible fittings are provided to replace removed portions of the existing pipeline and heat-fused to the polymer liner, and transition fittings provided to operably connect the replacement pipeline to those portions of the existing pipeline not within the replacement scope. The completed replacement polymer pipeline creates an operable wetted pressure boundary within the bounds of the replaced existing pipeline.