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MGDuff Ballast Tank Cathodic Protection

MGDuff Ballast Tank Cathodic Protection

MGDuff Ballast Tank Cathodic Protection

Product catalog summary
Introduction
M G Duff International Ltd. has been a leader in designing and supplying Cathodic Protection Systems for the shipping industry since 1954. Their services include design, inspection, and testing of marine cathodic protection systems, supported by a wide range of anode types available globally.
Corrosion in Ballast Tanks
Corrosion occurs in steel surfaces immersed in electrolytes, such as seawater in ballast tanks. Factors influencing corrosion include the nature of the electrolyte, steel quality, construction methods, and preventive measures. Saline ballast water, poor paint coatings, and lack of cathodic protection exacerbate corrosion.
Cathodic Protection Systems
Cathodic protection prevents underwater steel corrosion by introducing a more powerful corrosion cell with sacrificial anodes. Zinc and aluminum are commonly used metals, with aluminum offering better performance in higher resistivity water and cost advantages. MG Duff anodes are made from proven alloys.
Anode Design and Installation
MG Duff anodes are simple block castings with steel inserts for easy installation. Anodes should be positioned to avoid damage and ensure immersion in the electrolyte. They should be evenly distributed, focusing on uncoated areas and large steel surfaces. Safety regulations prohibit magnesium anodes in certain tanks due to explosion risks.
System Design Considerations
The design of cathodic protection systems depends on tank surface area, coating type and coverage, system life expectancy, ballasting frequency, and preferred anode material. MG Duff provides system design and installation drawings tailored to specific criteria.
Inspection and Maintenance
Routine inspections should ensure anode attachments are secure and free from insulating scale or rust. Anodes should be checked for activity, indicated by a soft white hydroxide deposit. Passivated anodes, with a hard crust, should be cleaned or replaced. Anode renewal is recommended before depletion below 15-20%.
Testing and Monitoring
Potential surveys ensure anode systems function correctly. Readings should be taken every three months at various tank heights. Low readings indicate the need for immediate attention to prevent ongoing corrosion. Testing requires ballast water of 1025RD, present for at least 48 hours.
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Catalog excerpts

MGDuff Ballast Tank Cathodic Protection-1

SHIP'S BALLAST TANKS USING SACRIFICIAL ANODES 1 Timberlaine Estate, Gravel Lane, Quarry Lane, Chichester, West Sussex. P019 8PP

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MGDuff Ballast Tank Cathodic Protection-2

M G Duff has been one of the world leaders in the design and supply of Cathodic Protection Systems to the Shipping Industry since 1954. This international service includes Design, Inspection and Testing of every type of Marine Cathodic Protection System, and is supported with the widest range of anode types, available at strategic locations throughout the world. Corrosion will occur to any steel surfaces immersed in a common electrolyte such as in the internal steel structure of a ships tank that is beneath the surface ballasted seawater. The extent of the corrosion will depend on the nature...

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MGDuff Ballast Tank Cathodic Protection-3

MGDuff Ballast Tank Anodes are simple in design, generally a block casting with a central steel round bar insert which are either double cranked to facilitate weld fixing, or straight for use with reusable clamps which avoid the need for "Hot Work" in the tank space. Other configurations are available such as flat bar inserts drilled to accommodate specific hole centres and anodes with integral clamps such as "pitguard" anodes designed for easy installation in cramped spaces such as double bottoms. The Pitguard anode will lie flat on the tank bottom clamped at one end to a steel frame. Anodes...

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MGDuff Ballast Tank Cathodic Protection-4

MG Duff have many years of practical experience on the installation and positioning of sacrificial anode systems and will prepare suitable system design and installation drawings to meet every design criteria. The type, number and position of anodes required depends upon several factors and the following information is required to determine the cathodic protection => The surface area of the tank or detailed tank drawings from which this can be => The type of coating, its coverage and anticipated breakdown over the life of => The required life of system (In general not to be less than 4 years)....

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*Prices are pre-tax. They exclude delivery charges and customs duties and do not include additional charges for installation or activation options. Prices are indicative only and may vary by country, with changes to the cost of raw materials and exchange rates.