Cathodic protection system using impressed current and galvanic action

摘要

Cathodic protection of steel in a building or other concrete or similar structure is provided by locating an anode in a suitable location adjacent to the steel and providing an impressed current from a power supply to the anode. The anode is formed from a material which is more electro-negative than the steel so that in the event that the power supply falls below the galvanic potential therebetween, current flows under galvanic action to replace the impressed current. A diode in the circuit prevents flow of current across the power supply but allows the galvanic current when the power supply fails open circuit. An additional diode can be provided in the event the power supply fails closed circuit to prevent reverse current flow.

主权项

1. A method for cathodic protection of steel material in a covering material id="REI-00001" date="20141111" comprising concrete, mortar or masonry material id="REI-00001" arranged such that at least a part of the steel material is at least partly covered by the covering material; the method comprising:
providing at least one anode member which is formed of a material which is more electro-negative than the steel material such that galvanic action will generate an electric potential difference therebetween tending to cause a flow of ions; arranging the anode member at least partly in contact with the covering material for communication of ions therebetween; providing an electrical connection arrangement between the at least one anode member and the steel material so that current can flow through said at least one electrical connection arrangement between the at least one anode member and the steel material so that ions flow through the covering material tending to inhibit corrosion of the steel material; providing a DC power supply having a supply potential difference greater than the galvanic potential difference between the anode member and the steel material generated by the galvanic action; connecting the DC power supply into said electrical connection arrangement such that the supplyto generate a potential difference causes ions to flow through the covering material tending to inhibit corrosion of the steel material for as long as the power supply is active to generate a supply potential difference greater than the galvanic potential difference between the anode member and the steel material generated by the galvanic action; and said electrical connection arrangement being arranged such that, when the power supply becomes inactive such that the supply potential difference falls below the galvanic potential difference between the anode member and the steel material generated by the galvanic action, current continues to flow through said electrical connection arrangement by the galvanic action to continue to provide cathodic protection to the steel material.