Open-Cell Polyurethane Foam for Pipeline Trench Stability
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Solution Overview
Problem
Existing polyurethane foams used for trench breakers in pipeline installations are prone to flotation and erosion due to water absorption, leading to pipe movement and settlement during heavy rains.
Innovation Solution
Development of a polyurethane foam with at least 50% open cells, a density of 1.30 lbs/ft3 to 3.50 lbs/ft3, and a minimum compressive strength of 17 psi, which exhibits a buoyancy loss of at least 20% after 24 hours under 10 feet of water, ensuring flotation resistance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing polyurethane foams are used for trench breakers, then they provide initial cushioning and erosion prevention, but they float when water soaks the trench, causing pipe movement and settlement
Solution Approach 1:
The foam is designed with an open-cell porous structure where at least 50% of the cells are open, allowing water to pass through rather than be absorbed and retained. This porous configuration enables the foam to maintain its structural integrity and buoyancy characteristics even when exposed to water, preventing flotation and the associated pipe movement problems
Solution Approach 2:
The foam's physical parameters are specifically controlled to achieve a density range of 1.30-3.50 lbs/ft³ and compressive strength of at least 17 psi. These parameter adjustments optimize the foam's performance by balancing its ability to resist water-induced flotation while maintaining sufficient mechanical strength for erosion prevention and pipe support
2Reliability
If the foam density is increased to prevent flotation, then buoyancy resistance improves, but the foam may become too heavy and lose its cushioning effect
Solution Approach 1:
The foam density is optimized within a specific range of 1.30-3.50 lbs/ft³, which balances flotation resistance and cushioning performance. This parameter optimization ensures the foam is dense enough to resist water-induced flotation while maintaining sufficient lightness and cellular structure to provide effective cushioning protection for pipes
3Ease of manufacture
If the foam is made with high open cell content for water drainage, then erosion prevention improves, but water absorption may increase leading to flotation
Solution Approach 1:
The open-cell porous structure with at least 50% open cells facilitates water drainage and reduces water retention, preventing the foam from becoming waterlogged and floating. The porous configuration allows water to flow through the foam rather than be absorbed, maintaining both erosion prevention capabilities and buoyancy stability
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 foam provides effective erosion prevention and stability for pipeline trench sites, preventing pipe movement and settlement, while maintaining sufficient strength and density to support trench pipes.
Implementation Method 1
the foam when tested in accordance with the American Society For Testing Standard Test Method For Water Absorption Of Rigid Cellular Plastics (ASTM D2841) exhibits a buoyancy loss of at least 20% after 24 hours of testing under 10 feet of water
Data Source
AI summary
The invention is directed to methods for supporting trench pipes with polyurethane foams which are flotation resistant with sufficient strength and density to provide stability and inhibit erosion at pipeline trench sites, and other uses, wherein at least 50% of the foam is open cell and has a density of approximately 1.3 lbs/ft3 to 3.5 lbs/ft3. The invention also provides methods for making compositions used to make polyurethane foams that exhibit such characteristics.