Tubular anodes have dense small projections throughout the entire anode surface so they can provide at least 20% more surface area than other conventional anodes. The increased surface area means low current density at certain current out or higher current out at a certain current density. The connection piece for tubular anodes is not only more superior by design but is also more protected by the anode itself. This design helps to reduce the electrolyte resistance and lower current density, compared to solid anodes with an equivalent anode weight and current output.
Our tubular anodes are chill-casted using our centrifugal process. The benefits of centrifugal casting are numerous and our tubular anodes manufacturing process offers the following advantages:
- At least 20% more surface area
- Rapid solidification by chill cast
- No molten metal-feed results in a much quicker cooling cycle
- A finer grain structure with low porosity
- Parallel wall section
- Centre cable connection
Tubular Anodes have many advantages resulting in them being named as the most reliable product in the industry for cathodic protection needs. The high surface area to weight ratio reduces the number of anodes that are needed to protect any one structure and extends the life of each of these anodes. The central connection ensures that all the anode material is consumed before the anode system will fail. This extends the life of the anode groundbed beyond conventional stick-anode groundbeds. The central connection also ensures a balanced spread of current throughout the length of the anode. This results in a reliable current discharge to the surrounding environment.
Specialist Castings is a major supplier of silicon iron anodes and is the only manufacturer capable of producing tubular anodes that can consistently pass x-ray inspection at level 1 and level 2 criteria.
The Centrifugal Casting Process
We have been manufacturing tubular anodes at our site in the UK for over 40 years. We manufacture these anodes by using a metal die that is rotating at speeds in excess of 1000 rpm. Molten metal is poured into the spinning mould and the very high centrifugal force generated by the rotating mould forces the metal to the outside of the mould forming a hollow tube. This production method has 4 measurable advantages over conventional die-cast and statically cast anodes;
- Because we use a metal mould, the molten metal solidifies very quickly, giving the best possible grain structure. Additionally, because there is no sand core at the centre of the mould, the cooling rate is not slowed down by the insulatory heat properties of the sand core.
- Once the metal is poured into the mould, the supply of metal is stopped and withdrawn from the rotating mould. This means there is no residual feed-metal attached to the anode that slows at a lower rate resulting in inferior grain-structure properties.
- Because the anode is straight-walled, there is no variation in cooling time between a thin section and a thicker section and the structure of the anode is maintained throughout its length giving no areas of weakness at any point in the anode.
- Because the centrifugal forces generated by the very high spin speeds are vastly in excess of gravitational forces operating when metal is simply poured into a sand or die-cast mould, the resulting grain structure throughout the anode is more compact and tighter, giving a superior structure and consequently a longer life.
The connection piece for tubular anodes is not only more superior by design but is also more protected by the anode itself. This design helps to reduce the electrolyte resistance and lower current density, compared to solid anodes with an equivalent anode weight and the connection at the centre of the anode reduces end-effect and increases the life of the anode.
In tests carried out by the Durichlor 51 company in the 1980s and 1990s it was found that our anodes(then branded Durichlor 51 anodes) only failed after 90% of the anode material had been consumed. We know of no other anode that has been tested that gives such dependable and reliable life expectancy. The testing and quality controls that include x-ray testing, raw material and chemistry controls, micro grain structure analysis all confirm our centrifugal method produces the highest quality anodes available.
We are currently carrying out comparative accelerated corrosion tests to compare our anode with other anodes and we are very confident that this will show there is no better anode available in the market. These results will be available at the start of 2017 and will be posted on this site.