The polymeric anode of "Raduga®" AZP-RA, AZP-RA-U, AZP-RA-K, AZP-RA-UK

The polymeric anode of "Raduga®" AZP-RA type is used in the cathodic protection systems against corrosion for underground metal structures. The main purpose of the device is to provide sufficient resistance in the soil so that the anode current does not spread beyond the design boundaries of cathodic protection and has an impact on the protected item. Anodes are designed for work with transformer rectifiers in any soil and climatic conditions when the electrodes are located below the depth of soil freezing.

It is known that the spreading resistance directly depends on the specific electrical resistance of the soil, however, as experimental studies and experience show, the spreading resistance is also influenced by the material from which the impressed current anode is made. This effect is most pronounced when using the impressed current anodes of AZP-RA type, based on a polymeric composite for soils with high resistivity (more than 100 Ohm * m). At that, the spreading resistance value decreases by 2–3 times in comparison with impressed current anodes made of ferrosilide alloys. This allows reducing the power of the transformer rectifier and increasing energy efficiency by 20-30%.

A feature of the polymeric composite of which the AZP-RA is made is that the anodic dissolution of carbon black is carried out in full; it allows obtaining stable calculated indicators of the main technical characteristics of the impressed current anode during the entire declared service life (at least 30 years).
The use of polymeric anodes of AZP-RA type also allows avoiding the danger of poisoning underground water supply sources with ferrous oxide and iron oxide to a considerable extent, as well as heavy metals when using AZ of AZZhK type and phenol when using impressed current anodes in a pitch coke coating. As during the anodic dissolution of AZP-RA, only H2O and CO2 are formed during the entire working period, which is environmentally friendly. When the warranty period and the complete anodic dissolution of carbon black are reached, the polymer matrix remains in the soil, neutral to the effects of the environment.

Advantages

The product is analogous to AZZhK, but has a number of advantages:
- It is made of a polymeric composite - it does not oxidize and not emit gas during use.
- Structural integrity, low weight and flexibility make transportation and installation simple and convenient.
- Durability. Service life is 20-30% longer than AZZhK I anodes.
- Environmentally safe.

Types of the impressed current anodes:

The impressed current anodes are produced in various modifications; the electrode is made of polymer with a diameter of 50 mm or 80 mm. Equipped with a cable outlet from one (non-looped) or two (looped) ends of the electrode connected to each other.

Polymeric anode of "Raduga®" AZP-RA type

The anode is a polymer electrode equipped with a cable outlet for connection to the main supply cable from the transformer rectifier.

Packed polymeric anode of "Raduga®" AZP-RA-U type

It is designed as a metal casing, in which a polymeric electrode is placed, and the free space between the electrode and the metal shell is filled with an anode space activator. It is designed for work in high resistance soils.

Complete polymeric anode of "Raduga®" AZP-RA-K type

It is supplied as a set of the required number of impressed current anodes with cable-outlets of the required length and main cable. The anodes can be connected to the main cable at the factory.

The mounting technique of surface anodic earthing depends on the anode installation method (horizontal or vertical positioning) and is determined by the cathodic protection project. Special modifications have been developed for laying at deep depths or in a well.  

Recommendations for application and operation of the impressed current anodes:

Application of all modifications of impressed current anodes of the AZP-RA type when soil resistivity is more than 60 Ohm * m. 
If soil resistivity in the range from 20 to 60 Ohm * m, it is recommended to use impressed current anodes of the AZP-RA type with a diameter of 80 mm. 
If soil resistivity is less than 20 Ohm * m, application of impressed current anodes of the AZP-RA type with a diameter of 80 mm.
- application of metal anode grounding conductors of AZZhK, ElZhK, AZM-RA types;  

When evaluating cathodic protection projects with the application of impressed current anodes of all types manufactured by ZNGA Anod LLC, it is required to use the "Cathodic protection calculation" program;
- when calculating through the use of nomogram, the real current load on the anode grounding, especially when calculating cathodic protection projects in soils with low resistivity shall be taken into account.