Bearings - 02/02/2010
NSK has demonstrated how its cost saving programme is relevant across all industry types, by delivering savings of €17,321 per annum - plus reduced maintenance and improved reliability - at a sewage treatment plant. The savings were gained as result of solving repeated failures of sealing arrangements on the bearings used in a large water pump, which is critical to the treatment process.
The seal failures were occurring 4 times a year, resulting in complete removal of the pump in each case, and resealing, a process which consumed three days. The cost of this 12 days unplanned maintenance per year was estimated at €15,780, with a further €1,541 per year in engineering support time.
Prior to consultation with NSK, engineers at the treatment plant upgraded the seal arrangement on the pump to a mechanical type in an effort to cure the repeated failures. However, this assembly, which included a locating bearing, was incompatible with the new seal arrangement and leakage still occurred.
With the problem still unresolved, engineers at the treatment plant turned to NSK for a solution. NSK operates a cost saving ‘problem solver’ programme across all industries, including water and waste treatment. The programme is designed for end-user bearing customers that are looking for more than just product supply. Rather, they are looking for a value-added service that actually helps them to reduce operating costs, improve efficiency and profitability.
After visiting the site and surveying the application, NSK engineers identified the cause of the sealing problem as excessive axial movement within the complete bearing assembly. The engineers recommended replacing the existing bearings with sealed duplex ball bearings. These bearings have 4 contact points, providing sufficient reduction of axial movement to allow the seal arrangement to function correctly.
The result of this bearing substitution is that unplanned maintenance has now been eliminated, resulting in a substantial improvement in overall plant reliability. To date, six of the thirteen pumps on site are fitted with the new bearings and seals, so further improvements in overall reliability can be expected when the remaining pumps are retrofitted with the same bearing solution.
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