Canadian Gas Research Institute

Canadian Gas Association

Sian Wah Khoo

Ranald L Hay

A method and apparatus for providing a continuous indication of the interior condition of a water heater tank are shown herein. Iron interior surface of water heater tank is normally protected from corrosion by cathodic protection with the provision of a sacrificial anode element made of a highly anodic metal. A zinc probe is incorporated in the water heater tank such that the potential measured between the zinc probe and the iron interior surface indicates the condition of the sacrificial anode element thus providing an indication of the effectiveness of the cathodic protection. The zinc probe may be conveniently incorporated in the drain cork of the water heater tank.

Hot water heater corrosion detector probe

This invention is directed to an improved sacrificial anode which consists of a magnesium or magnesium alloy core having a porous magnesium coating thereon. It is also directed to a method of preparing the anode including etching the anode surface, anodizing the anode for about 10 minutes in a solution of an electrolyte at a current density in the range of 10MA/cm.sup.2 to 50MA/cm.sup.2 using direct current at room temperature, subsequently reversing the current for about 5 minutes, allowing the anode to remain in the electrolyte for a period of about 30 seconds in the absence of current, re-anodizing the anode for about 10 minutes, again reversing the current for about 5 minutes and allowing the treated anode to remain in the electrolyte for a period of about 5 minutes in the abosence of current. This results in an improved anode which gives better protection for structures such as water heaters.

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Etobicoke, Canada

Sian Wah Khoo