Two stage cathodic protection system using impressed current and galvanic action

摘要

Cathodic protection of steel in concrete is provided by locating an anode assembly including both a sacrificial anode and an impressed current anode in contact with the concrete and providing an impressed current from a power supply to the anode. The impressed current anode forms a perforated sleeve surrounding a rod of the sacrificial anode material with an activated ionically-conductive filler material between. The system can be used without the power supply in sacrificial mode or when the power supply is connected, the impressed current anode can be powered to provide an impressed current system and/or to recharge the sacrificial anode from sacrificial anode corrosion products.

主权项

1. A method for corrosion protection of a metal section in an ionically conductive material comprising:
locating a sacrificial anode of a material which is less noble than the metal section in contact with the ionically conductive material; temporarily placing an impressed current anode in ionic connection with a surface of the ionically conductive material; providing a DC power supply; providing a connection of the DC power supply across the impressed current anode and the metal section so as to create a current between the metal section and the impressed current anode to provide cathodic protection of the metal section by communication of ions between the impressed current anode and the metal section through the ionically conductive material; and providing an electrically conductive connection between the sacrificial anode and the metal section to form a circuit with communication of ions between the sacrificial anode and the metal section through the ionically conductive material so that the sacrificial anode acts to provide cathodic protection of the metal section.