Non-Contacting Seal for Rail Freight Applications

Abstract

Due to increasing energy costs and emissions restrictions, many industries are paying closer attention to the energy required to keep their equipment operating. Parasitic losses in power such as those due to the drag produced by contacting lip seals that are found in a variety of rotating equipment can significantly add to the total operating costs of that equipment. In mobile industries (railroad, heavy truck, and automotive), these losses can significantly affect the amount of fuel consumed and emissions produced. Power losses due to seal drag are also accompanied with frictional heat and wear which can degrade components and lead to maintenance costs to service or replace these components. To address these issues for the railroad industry, Timken has developed a non-contacting seal for use in railroad bearings. A review is given of the design and development of a non-contacting labyrinth seal for railroad bearing applications. The seal has been qualified by the Association of American Railroads (AAR) for use in North America freight car service and is currently the only non-contacting seal in operation for this market. The unique design of the labyrinth pathway allows for zero seal drag with exceptional grease retention and contaminant exclusion capabilities as compared to contacting elastomer lip seals that are typical for this industry. Experimental test performance of this seal will be compared to other seals that are currently used in this industry. Operating torque reductions of 10–30 in-lb per seal achieved through this technology can lead to fuel savings on the order of hundreds of thousands of gallons per year corresponding to the elimination of thousands of tons of emissions due to the reduced fuel usage in the U.S. alone. These savings can be passed directly to railroads and freight car owners as well as the general population with lower operating costs, increased reliability, longer service life, and reduced emissions.