Recharging Sacrificial Anode with Impressed Current
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Solution Overview
Problem
Galvanic anodes used in steel reinforced concrete structures face limitations in mass and current output, leading to insufficient corrosion protection and short useful life, particularly in corrosive marine environments.
Innovation Solution
A method involving a sacrificial anode that is recharged with ions using an impressed current anode and DC power supply, allowing for extended operation by redepositing sacrificial anode ions, thereby enhancing corrosion protection and increasing the anode's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sacrificial anode is used to provide cathodic protection, then corrosion protection is provided, but the anode mass is depleted over time limiting its useful life
Solution Approach 1:
The patent recovers sacrificial anode material by reversing the corrosion reaction through applied current, converting dissolved metal ions back into solid anode material that can be redeposited on the anode structure, thereby extending its service life
Solution Approach 2:
The system enables continuous cathodic protection by periodically recharging the anode, allowing the protection function to continue indefinitely rather than being limited by finite anode mass consumption
2Duration of action of moving object
If the anode mass is increased to extend useful life, then duration of action is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The system uses the existing anode structure itself as the substrate for material redeposition, eliminating the need for separate replacement components or complex installation procedures while extending service life
3Reliability
If the current output of the anode is increased to improve protection effectiveness, then corrosion protection is enhanced, but the anode mass depletes faster reducing useful life
Solution Approach 1:
By implementing periodic recharging cycles, the system can sustain high current outputs for protection without permanent mass loss, as the consumed material is recovered and redeposited during off-protection phases
Solution Approach 2:
The system recovers metal ions that would otherwise be permanently lost during high-current operation, converting them back into solid anode material to maintain long-term protection capability
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 provides prolonged corrosion protection by recycling sacrificial anode material, reducing maintenance costs and ensuring continuous operation beyond the life of conventional zinc or aluminum anodes, while also offering backup protection mechanisms.
Implementation Method 1
causing the sacrificial anode to corrode preferentially in relation to the metal section such that ions of the sacrificial material are depleted from the sacrificial anode
Implementation Method 2
connecting a first terminal of a DC power supply to the impressed current anode so as to cause ionic current to flow through material to cause sacrificial anode ions to be deposited on the sacrificial anode
Implementation Method 3
the re-charging causes hydroxyl ions to be generated at the surface of the sacrificial anode
Data Source
AI summary
Cathodic protection of steel in concrete is provided by locating an anode assembly including both a sacrificial anode and an impressed current anode in contact with the concrete and providing an impressed current from a power supply to the anode. The impressed current anode forms a perforated sleeve surrounding a rod of the sacrificial anode material with an activated ionically-conductive filler material between. The system can be used without the power supply in sacrificial mode or when the power supply is connected, the impressed current anode can be powered to provide an impressed current system and/or to recharge the sacrificial anode from sacrificial anode corrosion products.