In-situ Additive Manufacturing of Large-Diameter OTEC Pipes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for manufacturing cold water pipes for Ocean Thermal Energy Conversion (OTEC) systems are time-consuming and require significant space, making them impractical for large-scale applications due to the need for long, large-diameter pipes that must be assembled in situ.
Innovation Solution
An additive manufacturing system that includes a lowering mechanism, extrusion head, gantry, and stabilizer to generate a long, large-diameter pipe in situ, using high-density polyethylene and varying the void-to-material ratio of the pipe wall based on operational depths to optimize structural integrity and buoyancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods (coupling segments or molding at deep water location) are used to manufacture cold water pipes, then the pipes can be assembled in situ, but the manufacturing time and space requirements become excessively large
Solution Approach 1:
The pipe is constructed segmentally through additive manufacturing, where material is deposited layer by layer to build up the pipe wall incrementally. This allows the pipe to be manufactured in situ without requiring large pre-manufacturing spaces, while maintaining the ability to assemble sections as needed.
Solution Approach 2:
The invention transitions from conventional 3D molding approaches to additive manufacturing that builds the pipe wall in a sequential dimensional approach, depositing material layer by layer around a mandrel. This dimensional transformation enables in-situ manufacturing without requiring large horizontal spaces.
2Ease of manufacture
If conventional methods (coupling segments or molding at deep water location) are used to manufacture cold water pipes, then the pipes can be assembled in situ, but the space requirements for molding segments become excessively large
Solution Approach 1:
The pipe manufacturing process is segmented into sequential additive deposition steps rather than requiring a single large molding operation. This allows the pipe to be built up incrementally in situ using minimal space, eliminating the need for large pre-manufacturing facilities.
Solution Approach 2:
The additive manufacturing system is self-contained and portable, bringing the manufacturing capability to the installation site rather than requiring the installation site to accommodate large manufacturing equipment. The system manufactures the pipe where it is needed using minimal local space.
3Productivity
If additive manufacturing is used to generate the pipe in situ, then manufacturing time and space are reduced, but the system complexity increases
Solution Approach 1:
The additive manufacturing system integrates multiple functions into a single platform: material storage and feeding, precision positioning of the extrusion head, layer-by-layer deposition control, and pipe wall formation. This multi-functionality achieves high productivity while managing system complexity through integration.
Solution Approach 2:
The system controls manufacturing parameters such as extrusion rate, deposition temperature, and layer thickness to optimize the pipe wall formation process. By precisely controlling these parameters, the system achieves high productivity and structural integrity without requiring excessively complex equipment.
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 significantly reduces the time and space required to manufacture cold water pipes, enhancing the practicality of OTEC systems by enabling faster and more efficient installation of long, large-diameter pipes.
Implementation Method 1
an extrusion head that is configured to receive material and to selectively extrude the material via a nozzle
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for generating a pipe assembly, comprises positioning a ring of material with respect to an extrusion head; coupling the ring of material to a lowering mechanism; extruding material on top of the ring of material to form a pipe wall on the ring of material; and iteratively: 1) lowering the ring of material and the pipe wall a predetermined distance; and 2) extruding the material on the pipe wall to extend the pipe wall until the pipe wall is a desired length.