Schaeffler Group USA Inc. and Master Rig International LLC have combined their experience and expertise to introduce unitized sheave units that significantly reduces maintenance requirements while significantly improving operational safety on many lifting jobs. Available immediately, this innovative technology effectively unitizes the bearing and seals within the sheave to create a self-contained, pre-lubricated assembly. These sheave bearing units can operate in a wide range of applications, including crown and traveling blocks as well as compensation systems on offshore rigs. By specifying this unitized sheave design, rig operators can effectively eliminate the time and expense typically required when performing maintenance on these critical bearing positions.
This new technology leans on designs developed by Schaeffler in similar applications over the past 60 years. Unitized sealed axle units (AP units), pioneered by the rail industry in the 1950s, are now standard equipment on both freight and passenger cars as well as in locomotive axles. After the rail industry adapted the unitized wheel bearing assembly, automotive manufacturers followed suit. Now, virtually all makes and models of cars on the road today use this bearing design concept. Similarly, the steel rolling industry has been successfully using sealed work roll bearings in extremely challenging mill environments since the 1990s. The experience gained from these varied industrial applications has enabled Schaeffler and Master Rig International to develop the right combination of basic seal design with the corresponding type and quantity of grease to significantly improve equipment performance in the harsh operating conditions faced by the oil & gas industry.
Schaeffler’s new sealed units are a drop-in replacement for current sheave bearing offerings. Because the bearing is never separated, the internal races are not exposed to harmful contaminants that are typically present at some installations. Master Rig International and Schaeffler have also developed special mounting procedures and tools to ensure that these innovative bearings are properly installed. Snap ring sheave designs can be retrofitted as well using existing grooves to lock the bearing into the sheave bore.
Since the recent introduction of this groundbreaking technology, many hundred unitized sheave assemblies have been installed in both new and existing sheaves, where they now operate in a wide range of environments on both on- and offshore rigs. This has resulted in reduced maintenance costs and improved safety as roughnecks are no longer required to locate grease fittings in extremely hazardous conditions.