Abstract A cathodic protection system for a metal substrate has an anode which is normally electrically insulated from the substrate but which is disposed very close to the substrate. Cathodic protection only becomes effective when the electrical insulation breaks down and the metal substrate would otherwise be subject to corrosion. The system comprises an electrically insulating coating on the metal substrate and an electrically conducting coating applied over the insulating coating, a D.C. voltage being applied between the metal substrate and the conductive coating. The conductive coating or the insulating coating or both may be paint, the conductive layer being rendered conductive by the incorporation of an electrically conductive material such as elemental carbon.
Inventors
👤 Philip James Gay
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-27 03:24
CPC Classifications
C; C23; C23F; C23F13/00; C23F13/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
90 words
A CATHODIC PROTECTION SYSTEM COMPRISING A METAL TO BE PROTECTED, AN ELECTRICALLY NON-CONDUCTIVE COATING APPLIED IN FLUID FORM OVER THE METAL, AN ELECTRICALLY CONDUCTIVE COATING APPLLIED IN FLUID FORM OVER THE NON-CONDUCTIVE COATING, SAID CONDUCTIVE COATING BEING RENDERED ELECTRICALLY CONDUCTIVE BY THE INCORPORATION OF ELEMENTAL CARBON THEREIN, SUCH THAT THE METAL AND ELECTRICALLY CONDUCTIVE COATING ARE ELECTRICALLY INSULATED ONE FROM THE OTHER, A SOURD OF D.C. VOLTAGE BEING CONNECTED BETWEEN THE METAL AND THE ELECTRICALLY CONDUCTIVE 11COATING SUCH THAT THE ELECTRICALLY CONDUCTIVE COATING IS ANODIC WITH RESPECT TO THE METAL.
Claim 2
Dependent Claim
90 words
A CATHODIC PROTECTION SYSTEM COMPRISING A METAL TO BE PROTECTED, AN ELECTRICALLY NON-CONDUCTIVE COATING APPLIED IN FLUID FORM OVER THE METAL, AN ELECTRICALLY CONDUCTIVE COATING APPLLIED IN FLUID FORM OVER THE NON-CONDUCTIVE COATING, SAID CONDUCTIVE COATING BEING RENDERED ELECTRICALLY CONDUCTIVE BY THE INCORPORATION OF ELEMENTAL CARBON THEREIN, SUCH THAT THE METAL AND ELECTRICALLY CONDUCTIVE COATING ARE ELECTRICALLY INSULATED ONE FROM THE OTHER, A SOURD OF D.C. VOLTAGE BEING CONNECTED BETWEEN THE METAL AND THE ELECTRICALLY CONDUCTIVE 11COATING SUCH THAT THE ELECTRICALLY CONDUCTIVE COATING IS ANODIC WITH RESPECT TO THE METAL.
Claim 3
Dependent Claim
16 words
A cathodic protection system according to claim 1, wherein said conductive coating is a paint composition.
Claim 4
Dependent Claim
24 words
A cathodic protection system according to claim 2 in which the electrically conductive coating has a resistivity of up to 1, 000 ohms/ft. sq.
Claim 5
Dependent Claim
22 words
A cathodic protection system according to claim 2 wherein the carbon content is up to 50 percent by volume of dried coating.
Claim 6
Dependent Claim
19 words
A cathodic protection system according to claim 2 wherein the conductive paint composition is a carbon-containing chlorinated rubber paint.
Claim 7
Dependent Claim
19 words
A cathodic protection system according to claim 2 wherein the conductive paint composition is a carbon-containing epoxy ester paint.
Claim 8
Dependent Claim
22 words
A cathodic protection system according to claim 2 in which the conductive paint composition is a carbon-containing chemically cured pitch epoxy paint.
Claim 9
Dependent Claim
18 words
A cathodic protection system according to claim 1 wherein there is another coating over the electrically conductive coating.
Claim 10
Dependent Claim
28 words
A cathodic protection system according to claim 1 in which the D.C. voltage source is of sufficient size to provide sufficient voltage to liberate chlorine from sea water.
Claim 11
Dependent Claim
24 words
A cathodic protection system according to claim 9 wherein the D.C. voltage source is of a size sufficient to provide at least 1.4 volts.