Composite Boss Galvanic Corrosion Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of electrically conductive carbon fiber composite bosses in pressure vessels is prone to galvanic corrosion during marine transport, particularly in salt-laden moist sea air, which increases the economic burden and viability issues of transporting compressed natural gas due to the weight and cost of metal bosses.
Innovation Solution
A non-conductive polymeric pressure vessel liner is integrated with a one-piece composite boss made from electrically conductive fibrous or filamentous material, where the non-conductive liner separates the boss from external materials, preventing galvanic corrosion by acting as a dielectric barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal bosses are used in pressure vessels, then strength and reliability are improved, but weight increases significantly
Solution Approach 1:
The patent applies composite materials by replacing traditional metal bosses with composite bosses made from carbon fiber reinforced polymer matrices. This substitution maintains the required mechanical strength while dramatically reducing the weight of the boss component, thereby improving the overall weight-to-strength ratio of the pressure vessel.
2Weight of moving object
If electrically conductive composite bosses are used, then weight is reduced, but galvanic corrosion occurs in salt-laden environments
Solution Approach 1:
The patent introduces a non-conductive liner as an intermediary barrier between the electrically conductive composite boss and the corrosive external environment. This liner prevents direct contact between the boss and salt-laden moisture, eliminating the galvanic corrosion pathway while allowing the lightweight composite material to be used.
Solution Approach 2:
The non-conductive liner creates a protected, inert environment around the composite boss by preventing exposure to the corrosive external atmosphere. This isolation mechanism shields the boss from electrochemical corrosion processes that would otherwise occur in marine or humid conditions.
3Reliability
If metal bosses are used, then manufacturing reliability is improved, but manufacturing complexity and cost increase for large vessels
Solution Approach 1:
The patent employs composite materials that can be manufactured using filament winding or molded processes, enabling large boss structures to be created as single-piece components. This approach simplifies manufacturing compared to traditional metal fabrication, which requires complex machining, assembly, and welding operations for large-scale bosses.
Solution Approach 2:
The integration of the boss directly into the pressure vessel structure eliminates the need for separate assembly operations. The boss is formed as an integral part of the vessel during the molding process, reducing manufacturing steps, assembly complexity, and potential failure points from connections.
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 solution significantly reduces the weight of pressure vessels, enhances the fluid-to-vessel weight ratio, and increases the value of transported natural gas by preventing galvanic corrosion, thus improving the economic viability of ocean transport.
Implementation Method 1
a problem may arise due to galvanic corrosion if the composite comes in contact with a substance having a different electrical potential
Implementation Method 2
the non-conductive liner is also contiguous to a proximal end surface of the boss, physically and electrically separating the end surface from galvanic corrosion-inducing contact with materials external to the pressure vessel
Data Source
Figure 1A~1C
Figure 1D~1E
Figure 2
AI summary
The present invention is directed to a pressure vessel comprising a conductive composite boss wherein the composite boss is isolated from contact with materials with different electrical potentials so as to substantially eliminate the possibility of galvanic corrosion.