For the past several years, Kingsbury has been working with major petrochemical-industry firms to develop hydrodynamic bearings capable of using process fluids as the lubricant. In 2009, two vertical canned motor pump applications emerged as possible candidates for bearings made with alternative materials. These pumps are designed and manufactured in Japan, while the first end customer was located in the United States. The pumps are designed to handle various fluids, among them diesel fuel. Given the lubricants, we proposed the use of stainless steel thrust bearings with tilting pads made of Vespel® instead of the usual carbon steel type lined with tin-based babbitt. Vespel® was chosen due to its superior lubricity properties, manufacturability, moderate cost and availability. The bearing sizes range on the outer diameter from as small as 100 mm (4") to 279 mm (11"), with up to eleven pads per side, and all but one of the designs are non-equalized.
As of February 2012, a total of 50 pump sets of bearings have been sold. The bearings have performed admirably with both lubricants, and it is our intention to continue promoting alternative bearing liners for such applications.