The anodes in impressed current systems can be installed in the most diverse configurations, according to the kind of structure. In maritime installations, the anodes hang between the structures or stay at the bottom of the sea, or, yet, fixed on the structure itself, on a special device.
Iron-Silicon-Chrome anodes for impressed current cathodic protection.
Anotec Anodes are used to provide electric current through soil and natural waters so structures are protected through corrosion mitigation. During the process, the anodes are slowly consumed.
The Anodes used in impressed current system differ fundamentally from the galvanic anodes because they are inert, and consequently are wear-resistant and have a longer life.
The main characteristics are:
. Density of the admissible current
The density of admissible current is included in the characteristic data of the kind of material used in manufacturing. The use of a current density above the recommended maximum can cause extreme and irregular wear to the anode. In certain cases, it can cause insulating products to appear on the surface.
. Anode Wear
Each kind of anode has a known wear rate, whenever it operates within the maximum current density level. The rate of stress of a certain kind of anode needs to be considered for the calculation of its life. In general, the bed is designed for a minimum life from 15 to 20 years.
The electric contact resistance between the node and the electrolyte is a function of the size of the anode and the resistivity of the electrolyte. Therefore, once the installation is defined, the resistance of each anode will depend on its size. An addition in the length or in the diameter of the anode will result in a reduction of the resistance; however, the influence of the length is well over that of the diameter. The total resistance of the anode bed when applied in soils with average to high resistivity is, in general, the factor that defines the number of anodes to be employed.
The iron, silicon, and chrome anodes (Fe-Si-Cr) are manufactured in circular bars, through foundry, with silicon content of 16% and chrome content of at least 4%. They are recommended for soils, sea water, sea bottom and fresh water.