Impressed current anode
The use of impressed current anodes is a method for prevention of corrosion (the best known example is the formation of rust ) in buildings, pipes and containers made of steel or other metals . Corrosion is an electrolytic process with electrical charge transport . By applying an electrical voltage of opposite polarity to the electrode potential between the material at risk of corrosion and the external current anode, the corrosive material removal can be effectively prevented. In contrast to a sacrificial anode, no material is removed from the anode in this process.
Working method
External power systems are operated with direct voltage , which must be provided by a power supply unit . The negative pole of the power source is connected to the metal to be protected and the positive pole to the external current anode. The voltage between the external current anode and the protected object is set manually or automatically on the power supply unit. This results in the respective protective current effect.
Therefore, in contrast to sacrificial anodes, impressed current anodes do not need to have a negative redox potential compared to the material to be protected. The cathodic protective current shifts the potential at the interface in the vicinity of the external current anode in a negative direction. If a certain potential value is reached, the corrosion removal of the protected object is technically negligible.
costs
For enamelled hot water tanks with a volume of up to 1000 liters, the power consumption of a supply part for the external current anodes is, for example, around 3 watts ; the annual electricity requirement is thus around 26 kilowatt hours . A complete set of components, consisting of anode, cables and supply part, costs 150… 300 EUR.
The costs are more than compensated by the omission of maintenance.
Typical application examples
- Pipes that are laid in the ground, in particular oil - pipelines
- Underground tanks and similar containers
- Structures made of steel such. B. Bridges
- Structures made of steel-reinforced concrete
- Ship hulls
Web links
- petroplan.ch: What is cathodic protection?
- Impressed current anode
Individual evidence
- ↑ a b Study Committee for Corrosion and Corrosion Protection of Pipelines (Ed.): Practical Guide for Cathodic Corrosion Protection . 2nd Edition. expert verlag, Ehningen near Böblingen 1991, ISBN 978-3-8169-0588-2 , p. 15 ( limited preview in Google Book search).
- ↑ a b https://www.heima24.de/heizung/fremdstromanode-aces-g2-400-mm-fuer-warmwasserspeicher-bis-1000-liter-mit-adapter-fuer-34-1-und-1-14 .html impressed current anode ACES G2 400 from CGR srl, accessed on April 17, 2020
- ↑ https://www.weinmann-schanz.de/xs_db/xs_dokumente/www/ws/Download_Kataloge2014/WS_Ersatzteil_Leitfaden_2014_2015/WSDE14_Ersatz_K06_geschuetzt.pdf Fremdstromanoden CORREX, accessed on April 17, 2020