Roulements - 17/09/2009
Because Centrifugal pumps are so central to all types of processes, failures can result in catastrophic consequences, which can be both hazardous and costly. Maximising bearing performance and reducing any potential pump failures is therefore critical.
NSK has worked with the global pump industry to meet these operating demands, and the result is the HPS™ (High Performance Standard) range of Angular Contact Ball Bearings. The basic dynamic load rating of these bearings has been improved by 20% increasing bearing L10 life1 by up to 90%. This allows for longer maintenance intervals, and can enable a reduction in bearing size for new pump designs.
The optimal design characteristics that provide longer life operation on the HPS™ series are also key to the higher speed operation of the bearings; permissible speed being increased by 15 – 20% compared to conventional angular contact ball bearings. The major benefit of this increase for pump users is reduced operating temperatures, enabling the bearings to operate in a higher range of high-speed pumping applications.
The efficiency of the HPS™ design also means that the bearing’s improved higher speed capability is delivered at the same time as bearing accuracy is maximised. This is evidenced by a running accuracy to ISO tolerance class P5 and a dimensional accuracy to ISO tolerance class P6. These tolerances enable tighter control of shaft run-out, aiding the performance of the mechanical seal and improving overall pump efficiency.
A choice of three cage materials enables the HPS™ series bearings to be easily configured to meet the operating requirements of most pumping applications. The cage materials include: Glass fibre reinforced polyamide 46, which provides high strength even at high temperatures; L-PPS resin, for applications where chemical and oil resistance is critical; and Machined brass, which offers high reliability, and compliance with API 610 standards.
The HPS™ range of Angular Contact Ball Bearings are available in the 7200 series and 7300 series, from 12mm bore to 80mm bore, and can be retrofitted during general maintenance to upgrade standard industrial bearings, or included during the initial design to provide superior performance.
1L10 life means that, statistically, at least 90% of the bearings exposed to the maximum indicated loads will reach the number of operating hours predicted.
HPS™ BEARING SERIES
In addition to angular contact bearings, NSK’s HPS™ bearing series also includes innovative spherical roller bearings (SRB). These bearings offer innovative performance with twice the running life compared to conventional SRB of the same size; and a maximum limiting running speed that has been improved by up to 20 %. The HPS™ series provides significant benefits across major industry sectors such as extraction, steel, construction and transport, by reducing maintenance and energy costs, and enabling product downsizing.