Segmented Anode Ring for Ship Seawater Inlet Corrosion

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Solution Overview

Problem

Existing ship protection systems against fouling and corrosion at sea water inlets and pipelines are complex and often leave critical unprotected areas, particularly in submarines, where diving pressure and anode exchange pose challenges.

Innovation Solution

A ring-shaped anode arrangement with half-rings made of copper and aluminum, insulated with polyurethane, is fixed at the seawater inlet, allowing for efficient ion release and easy exchange, with electrical connections on the outer circumference and through-holes for stress relief, and a zinc ring for conductive connection to the hull.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If impressed current anodes are installed in pipe sections at a distance from the seawater inlet, then corrosion protection is provided to pipe sections, but a critical pipe section with unprotected area remains between the seawater inlet and the corrosion protection unit

Engineering Contradiction:
Improvecorrosion protection coverageVSAvoidprotection system arrangement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The anode is divided into multiple segments (first anode segment and second anode segment) that are arranged at different locations along the pipe section. This segmentation allows comprehensive coverage of the pipe including the critical area near the seawater inlet, while maintaining modular installation and replacement capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The anodes are arranged in a spatial distribution along the pipe length rather than at a single location. This dimensional arrangement ensures that the electrical protection field covers the entire pipe section including the vulnerable area near the inlet, transforming a point-protection approach into a distributed linear protection system.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If sacrificial anodes are used for corrosion protection, then corrosion resistance is improved, but the anodes require replacement over time and installation complexity increases

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidanode replacement
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The anode system is segmented into replaceable modules that can be individually accessed and replaced. The first and second anode segments can be independently maintained, allowing repair operations to be performed on one segment without disturbing the other, thus simplifying maintenance procedures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A connection structure serves as an intermediary between the anode segments and the pipe, facilitating easy installation and replacement. This intermediary connection mechanism allows anodes to be swapped without complex disassembly of the entire protection system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If copper anodes are used to kill organisms and prevent fouling, then fouling prevention is improved, but copper ion dissolution requires continuous ion release which consumes the anode material

Engineering Contradiction:
Improvefouling preventionVSAvoidanode service life
Core Design Contradiction:
Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The fouling prevention function is distributed across multiple anode segments that can be replaced independently. When one segment is consumed, only that segment needs replacement rather than the entire anode system, extending the overall service life of the protection system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The segmented anode design allows for selective replacement of consumed segments while retaining functional segments. This partial replacement strategy optimizes resource utilization and extends the total operational duration of the corrosion and fouling protection system.

Inventive Principle:
Principle #34Discarding and recovering

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 provides robust, water-tight corrosion protection with minimal contact areas, enabling effective fouling prevention and corrosion management, even under high pressure, and facilitates easy anode exchange and power supply.

Implementation Method 1

copper ions dissolved in seawater have been shown to kill organisms, preventing them from accumulating in pipes

Methodology Applied
Scientific EffectIon dissolution: Solvation

Implementation Method 2

copper ions dissolved in seawater have been shown to kill organisms, preventing them from accumulating in pipes

Methodology Applied
Scientific EffectBiocidal action:

Implementation Method 3

dissolved aluminum (aluminum ions) serve as corrosion protection. The aluminum ions integrate into the typical passive layer of CuNi10Fe pipes used for seawater pipelines and further stabilize them

Methodology Applied
Scientific EffectIon dissolution: Solvation

Implementation Method 4

The formation of a passive layer provides corrosion protection and is the reason why CuNi10Fe is used on special ships

Methodology Applied
Scientific EffectPassive layer formation:

Implementation Method 5

a zinc ring for conductive connection to the hull

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 6

The natural sulfide content of the seawater coupled with sulfate-reducing organisms and bacteria are the reason for corrosion reactions of metallic surfaces in the form of electrochemical corrosion

Methodology Applied
Scientific EffectElectrochemical corrosion:

Implementation Method 7

traditional sacrificial anodes, and impressed current anodes to protect vulnerable metallic materials from attack and destruction by chemical or electrochemical reactions

Methodology Applied
Scientific EffectSacrificial anode protection:

Data Source

PatentEP2218636B1Device for protecting ship seawater intakes from corrosion and fouling
Publication Date: 2013.09.04 THYSSENKRUPP MARINE SYST GMBH
  • EP2218636B1 patent drawingFigure 1~2
  • EP2218636B1 patent drawingFigure 3~4

AI summary

The device has an anode ring (1) that is designed as a flange-like ring and fixed at a sea water inlet. The anode has half rings (2, 3) that are made of different materials such as copper and aluminum for releasing free ions. The half rings are partially isolated by a plastic coating. A receiving area at the sea water inlet is isolated by a casing (4). The anode ring has an internal area that is turned towards sea water and formed as a passage area (5) without isolation. The plastic coating consists of plastic such as polyurethane.