Pressure Vessel Barrier Layer Coating Under Internal Pressure
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Solution Overview
Problem
Existing pressure vessels face issues with hydrogen permeation through metal coatings, which can lead to layer fractures due to expansion, reducing the barrier effect and increasing the risk of fuel escape.
Innovation Solution
A method for producing a barrier layer in a pressure vessel where the coating is applied during an expanded state under high internal pressure, ensuring the layer is compressed when internal pressure decreases, using chemical or electrochemical deposition methods, and incorporating an adhesion-promoting layer to enhance adhesion and reduce fracturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal coating is applied on the external side of the pressure vessel to reduce hydrogen permeation, then the permeation barrier effect is improved, but the coating may fracture due to expansion-induced stress accumulation
Solution Approach 1:
Instead of applying the coating on the external side where expansion causes tensile stress and potential fracture, the invention inverts the approach by applying the coating on the internal side of the pressure vessel. This ensures that during expansion, the coating is compressed rather than stretched, preventing fracture and maintaining coating integrity while still providing effective hydrogen permeation barrier protection.
Solution Approach 2:
The invention changes the parameter of coating location from external to internal surface, and modifies the stress state from tensile to compressive during vessel expansion. This parameter change fundamentally alters the mechanical behavior of the coating under operational conditions, preventing the fracture issue while maintaining the permeation barrier function.
2Adaptability or versatility
If the pressure vessel undergoes functionally-determined expansion to accommodate pressure changes, then the operational flexibility is improved, but this expansion causes stress accumulation that leads to coating fracture
Solution Approach 1:
The invention inverts the traditional coating placement from external to internal surface. This inversion changes the stress state experienced by the coating during pressure-induced expansion from tensile (prone to fracture) to compressive (fracture-resistant), allowing the pressure vessel to maintain operational flexibility while preserving coating integrity through the expanded state.
3Reliability
If the barrier layer is applied to ensure complete coverage and prevent fuel permeation, then the safety is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention applies preliminary action by coating the internal surface of the pressure vessel before the vessel undergoes its first expansion cycle. This timing ensures that the coating is applied to a stable, non-expanded structure, simplifying the manufacturing process while still achieving complete coverage and effective permeation prevention, as the subsequent expansions will compress rather than stress the already-applied coating.
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 method significantly improves the permeation barrier effect by minimizing fractures and maintaining the barrier layer's integrity, even under varying pressure conditions, thereby preventing fuel escape and extending the vessel's operational lifespan.
Implementation Method 1
The barrier layer serves for the reduction, and preferably for the avoidance, of fuel-permeation
Implementation Method 2
the barrier layer can provide a minimized free volume, i.e. by way of example in the case of polymers only little free space between the molecular chains. As a general rule, diffusion is inhibited by a high filler content or a high crystallinity
Data Source
AI summary
A method of producing a barrier layer of a pressure vessel includes applying the barrier layer to a liner and/or to a fiber-reinforced layer of the pressure vessel while a pressure difference between the internal volume and the surroundings of the pressure vessel is being maintained.