Advanced Materials for Demanding Bearing Applications

Advanced Materials for Demanding Bearing Applications There is a wide range of rotating equipment that experience temperatures, loads and lubrication conditions outside the normal limits of whitemetal bearings. Advanced materials such as polymers and ceramics offer bearing designers alternatives with which to provide successful solutions. A summary of applications benefiting from the performance of non-metallic materials is provided in the new Waukesha Bearings brochure dedicated to such bearings. Polymer bearings have been used in the high load, high temperature borehole environment for the past 25 years. Their use is now spreading to gas turbines to withstand the high temperatures associated with heat soak offering potential savings on the capital cost of equipment. A new range of high load capacity polymer thrust bearings has been developed and tested in the field for water-lubricated pumps and motors. These have enabled the replacement of existing bearings based on ferrobestos materials. Polymers are also running on the low viscosity working fluids used in Organic Rankin Cycle turbines generating electricity from waste heat sources such as landfill gas and the exhaust gases from diesel engines and gas turbines.Ceramic materials continue to play a leading role in process lubricated applications especially where abrasive particles are present in the lubricant. Pumps using ceramic bearing solutions are more compact with no external oil-lubricating system and fewer seals. Topside water-injection pumps have utilised these benefits for many years. This experience is currently being applied to the growing market for subsea, water-injection and boosting pumps where the elimination of mechanical seals offers significant improvements in reliability. Advanced materials commonly extend bearing performance by operating at thinner films and higher temperatures. Their successful utilisation involves a mixture of application experience and bearingdesign with materials knowledge to ensure correct lubrication and optimised performance. Additional benefits are derived from other properties including high electrical resistance and low coefficients of friction, resulting in reduced start-up torque.