Cathodic protection

US6572760B2 · kind B2 · utility

Inventor

• David Whitmore · Winnipeg, CA

Key dates

• Filing date: Jul 24, 2001
• Grant date: Jun 3, 2003
• Expiry date: Aug 24, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23F2201/02
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Cathodic protection of a structure including a steel member at least partly buried in a covering layer, such as steel rebar in a concrete structure, is provided by embedding sacrificial anodes into the concrete layer at spaced positions over the layer and connecting the anodes to the rebar. Each anode is inserted into a drilled hole in the layer and is electrically attached to the rebar in the same or an adjacent hole by a steel pin which is attached to the reinforcement by arc welding or by impact. In the arrangement where the anode and the attachment are in the same hole, the pin passes into or through the anode so as to hold the anode rigidly within the hole. The hole is filled by a settable filler material. In order to maintain effective current conduction from the anode to the reinforcement through the filler and the concrete over an extended period to maintain the required protection, there is added to the filler, to a covering layer on the anode body or to the anode body itself a first material to hold the pH at the anode in a preferred range of the order of 12 to 14 and a second humectant material to absorb moisture.