Pultruded Arc-Segmented Pipe for OTEC
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Solution Overview
Problem
The commercialization of ocean thermal energy conversion (OTEC) systems is limited by the challenges of fabricating, transporting, and installing large-diameter, long-length cold-water pipes, which are typically heavy, labor-intensive to join, and pose safety risks during assembly and submersion.
Innovation Solution
The manufacture of large-diameter, long-length pipes is achieved by forming pultruded segments via a pultrusion process and joining them side-by-side, either using a rapidly curing adhesive or snap-together technology, allowing for the creation of pipes exceeding 1000 meters in length with reduced weight and labor requirements, and enabling on-site fabrication and installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional metal pipes are constructed using rolled sheets that are welded and internally stiffened via rings, then the pipe achieves sufficient strength and stiffness, but the pipe becomes very heavy and requires extensive skilled welding labor
Solution Approach 1:
The patent employs composite materials consisting of a corrosion-resistant metal liner (such as stainless steel or aluminum) combined with a structural outer layer (such as concrete, polymer concrete, or composite wrapping). This composite construction provides the necessary strength and stiffness while significantly reducing the overall weight compared to conventional all-metal pipes, as the structural layer provides mechanical strength without the density of solid metal
2Strength
If concrete pipes are slip formed and pre-tensioned to achieve required strength, then the pipe achieves sufficient structural integrity, but the pipe becomes exceedingly heavy and joining circular segments becomes very difficult
Solution Approach 1:
The patent uses composite construction with a metal liner and structural outer layer, which provides the necessary structural integrity through the combination of materials rather than relying solely on heavy concrete. The metal liner provides tensile strength while the outer structural layer provides compression strength, achieving required strength with reduced weight compared to conventional concrete pipes
3Weight of moving object
If composite pipes are fabricated with filament-wound inner laminate, core, and outer laminate to reduce weight, then the pipe becomes lighter, but the length of unitary sections is limited to only a few meters requiring many butt joints
Solution Approach 1:
The patent divides the pipe into modular sections that can be fabricated using pultrusion or similar processes. These sections are designed with connection features (such as bell-and-spigot joints, flanged connections, or interlocking mechanisms) that simplify assembly. The segmentation allows for lighter individual sections that are easier to handle and install, while the standardized connection designs reduce the overall complexity of joining multiple sections compared to conventional butt joints
4Length of moving object
If many butt joints are used to assemble long-length pipes from shorter sections, then the pipe can achieve required length, but each joint becomes a weak spot and the joining process becomes very labor intensive
Solution Approach 1:
The patent employs specially designed connection features between pipe sections (such as bell-and-spigot joints with gaskets, flanged connections with bolting patterns, or interlocking mechanisms) that create reliable, leak-tight seals. These standardized connection designs distribute stresses evenly and provide mechanical strength comparable to or exceeding the pipe wall itself, eliminating the weak spot problem associated with conventional butt joints
5Ease of manufacture
If conventional large-diameter pipes are fabricated and then transported to the OTEC plant, then the pipe can be installed, but transportation is expensive and raises safety concerns
Solution Approach 1:
The patent divides the pipe into manageable modular sections that can be transported using standard equipment and then assembled on-site. This segmentation reduces transportation risks by eliminating the need to handle and transport extremely long, heavy pipes as single pieces. The modular sections can be transported in smaller, safer loads and assembled using pre-designed connection features, significantly reducing transportation costs and safety concerns
6Ease of operation
If the pipe is up-ended (or assembled and then up-ended) for submersion into the ocean, then the pipe can be installed, but this is a difficult and potentially quite risky procedure
Solution Approach 1:
The patent employs modular pipe sections with standardized connection features that can be assembled in a horizontal or near-horizontal position using standard equipment. This eliminates or minimizes the need for dangerous up-ending operations, as sections can be connected side-by-side or end-to-end in controlled positions and then lowered into the ocean as a complete or partially assembled structure, significantly reducing installation risks
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 method allows for the cost-effective and safer production of long-length pipes with reduced weight and labor, facilitating the installation of OTEC systems by eliminating the need for extensive welding and minimizing the risk of assembly and transportation hazards.
Implementation Method 1
Each of the plurality of segments is formed via a pultrusion process
Implementation Method 2
The segments are then joined together, either with a rapidly curing adhesive (e.g., UV-curing underwater adhesive)
Implementation Method 3
The segments are joined side-by-side (i.e., along their length)... either using a rapidly curing adhesive or snap-together technology
Data Source
AI summary
A method for forming a large diameter and very long pipe comprises forming a plurality of pultruded segments via pultrusion and joining the segments along the lengthwise edges thereof.