Bearing change eliminates premature seal failures

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NSK has helped a sewage plant operator to save EUR17,321 per annum and reduce maintenance requirements.

Bearing change eliminates premature seal failuresNSK has demonstrated how its cost saving programme is relevant across all industry types by delivering savings of EUR17,321 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 that is critical to the treatment process.

The seal failures were occurring four times a year, requiring complete removal of the pump in each case, then resealing them - which took three days. The cost of these 12 days of unplanned maintenance per year was estimated to be EUR15,780, with a further EUR1541 per year in engineering support time.

Prior to consulting 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, the engineers turned to NSK and the company's cost saving 'problem solver' programme. 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 helps them to reduce operating costs, improve efficiency and boost profitability.

Sealed duplex ball bearings

After visiting the site and surveying the application, the NSK engineers identified the cause of the sealing problem as excessive axial movement within the bearing assembly. They recommended replacing the existing bearings with sealed duplex ball bearings. These have four contact points, providing sufficient reduction in axial movement to allow the seal arrangement to function correctly.

The result of this bearing substitution is that unplanned maintenance has been eliminated, resulting in a substantial improvement in overall plant reliability. To date, six of the thirteen pumps on site have been upgraded 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.

Use the form on this page to request a callback or more information about the cost saving programme.

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