Method and apparatus for cathodically protecting reinforced concrete structures

Abstract

Galvanic protection of a reinforced concrete structure or a metallic structure immersed or partially immersed in water or seawater utilizes a sacrificial anode having a more negative electrode potential than that of the metal to be protected but connected to the reinforcement or metallic structure, and the anode immersed in electrolyte solution creating an corrosive environment for the anode. The electrolyte solution must exist for internal charge transfer by ionic conductance, and to complete the electric circuit of the galvanic cell therefore both the metal or reinforced structure and the sacrificial anode have to be immersed in an electrolyte solution. The anode will provide in that way sufficient current to protect the reinforcement or metal structure against corrosion. The present invention resides in a method where the sacrificial anode immersed in an electrolyte solution can be positioned on a remote location e.g. in a small container away from the reinforced concrete or metal structure. This is done in a manner that both electrolyte solutions in which one electrolyte solution the metal or reinforced structure is immersed and second electrolyte solution the anode is immersed are connected through two metallic non-corrosive current distributors providing an electrical bridge between both electrolytes. The current density can be adjusted by increasing or decreasing the surface area of the current distributor immersed in the electrolyte solution in which the anode is immersed.

What I claim as my invention is:  
     
         1 ) A method of galvanically protecting a reinforced concrete structure comprising the steps of: 
 (a) electrically connecting a sacrificial anode to the steel reinforcement of the concrete structure, the anode having a more negative electrode potential than that of the steel reinforcement;    (b) the sacrificial anode to be immersed in an electrolyte solution creating a corrosive environment for the anode, and providing in that way sufficient current to protect the reinforcement against corrosion;    (c) the sacrificial anode immersed in an electrolyte solution being positioned on a remote location e.g. in a small container away from the reinforced concrete;    (d) providing an electrical bridge between both the electrolyte solutions by electrically connecting the current distributor which is immersed in the electrolyte solution in which the anode is immersed and a current distributor applied on the surface of the reinforced concrete.    
     
     
         2 ) A method of galvanically protecting a steel or metal structure immersed or partially immersed in water or seawater or any other electrolyte solutions comprising the steps of: 
 (a) electrically connecting a sacrificial anode to the steel or metal structure immersed or partially immersed in water or seawater or any other electrolyte solutions, the anode having a more negative electrode potential than that of the steel or metal structure;    (b) the sacrificial anode to be immersed in an electrolyte solution creating a corrosive environment for the anode, and providing in that way sufficient current to protect the steel or metal structure immersed or partially immersed in water or seawater or any other electrolyte solutions against corrosion;    (c) the sacrificial anode immersed in an electrolyte solution being positioned on a remote location e.g. in a small container away from the steel or metal structure immersed or partially immersed in water or seawater or any other electrolyte solutions;    (d) providing an electrical bridge between both the electrolyte solutions by electrically connecting the current distributor which is immersed in the electrolyte solution in which the anode is immersed and a current distributor which is immersed in the water or seawater or any other electrolyte solutions in which the steel or metal structure is immersed.