Performance enhancing coating for water heater

A water heater, comprising:

• a tank including a wall defining an interior, said wall including corrodible material exposed to said interior;
• an inlet for introducing water into said tank;
• means for heating water in said tank;
• an outlet for discharging hot water from said tank;
• and
• a coated anode mounted in said interior for protecting exposed areas of said corrodible material from corrosion by hot water stored in said tank, said anode including an uncoated portion of active anode metal over its lower end away from the tank connection, and a coated top portion adjacent to this connection, said coated portion including an inner layer of anodic material, an intermediate layer of anode/coating reaction products, and an outer layer of cured coating, said coating being coated over said anodic material to substantially reduce electrochemical activity of said anodic material in said coated portion and conserve said anodic material in said coated portion for use at a future time when said coating has dissolved and after the uncoated portion of the anode has been largely used up at a slower rate protecting said exposed corrodible metal in the tank head, and said corrodible metal's reactivity with hot water has been reduced from prolonged service, said coating thus extending overall anode life well beyond that of a conventional uncoated anode by a second mechanism besides protection from necking and premature break-off.

A water heater, comprising:

• a tank including a wall defining an interior, said wall including corrodible material exposed to said interior;
• an inlet for introducing water into said tank;
• an electric heating element mounted in said tank for heating water in said tank, said electric heating element including corrodible material;
• an outlet for discharging hot water from said tank;
• and
• an anode mounted in said interior for protecting said corrodible material from corrosion by hot water of the tank, said anode including an uncoated portion consisting of anodic material, said anode including a coated portion near said heating elements, said coated portion including an inner layer of anodic material, an intermediate layer of coating material and anodic material reaction products, and an outer layer of cured coating, said coating including particles of said anodic material, said coating being coated over said anodic material to substantially reduce electrochemical attack by the strong electrical fields associated with said heating elements on said anodic material in said coated portion and conserve said anodic material in said coated portion and so distribute said electrochemical attack on said anodic material more uniformly over its surface, thereby extending the life of said anodic material near such strong electric fields.

A water heater, comprising:

• a tank including a wall defining an interior, said wall including corrodible material exposed to said interior;
• an inlet for introducing water into said tank;
• means for heating water in said tank;
• an outlet for discharging hot water from said tank;
• and
• an anode mounted in said interior for protecting said corrodible material from electrochemical corrosion by hot water stored in said tank, said anode including an inner layer of anodic material and an outer layer of an activating coating, said anodic material having an electrochemical activity which is insufficient to protect said corrodible material from excessive corrosion, and said activating coating being coated over certain areas of said anodic material to increase the electrochemical activity at these areas only to a level sufficient to prevent excessive corrosion of said corrodible material without increasing said anode's activity near its connection to the tank, so that necking and premature break-off are limited by the anode material's own low activity there.