Shaft seal resistant to electrokinetic corrosion

In combination with a shaft, a housing, and means mounting said shaft for rotation within said housing, a shaft seal for preventing the leakage of liquid between said shaft and said housing, said shaft seal comprising:

• a stationary first annular seal element associated with said shaft housing;
• said shaft extending through said first annular seal element;
• a second annular seal element;
• means mounting said second seal element on said shaft for rotation therewith;
• each of said seal elements having a respective mating surface;
• means for urging said mating surfaces together to provide rubbing engagement between said mating surfaces during said rotation;
• one of said two seal elements being composed of a material having a relatively high hardness;
• the other of said two seal elements being composed of a material having a relatively low hardness which allows the harder of the two seal elements to conform the softer seal element to the harder one;
• both of said seal elements being composed of a material which will not support an electrochemical reaction;
• said mounting means for said seal elements and said respective compositions of the seal elements comprising means for conforming the mating surface of said other seal element to the mating surface of said one seal element, on a macro scale, when said mating surfaces undergo said rubbing engagement, during said rotation;
• and means, including the respective composition of each seal element, for substantially eliminating electrokinetic corrosion at said mating surface thereof when the shaft seal is used to prevent leakage of an electrolytic liquid.