Bearing the contamination of foul water

The challenge for any water and wastewater operation is in keeping the equipment running efficiently in spite of the harsh conditions and contamination it is exposed to. Foul water contamination in particular will affect the life of essential components such as bearings in rotating machinery. This is why a triple-sealed bearing is often recommended for applications in the water treatment sector.

“Simply put: If you’ve got bearings that are subject to ingress by water, they are in danger of failing,” says Tony Tormey, BSC’s Product Manager of Industrial Bearings. “This is why a triple lip sealed bearing, such as that manufactured by NSK, is ideal for these kinds of applications. The triple seal will increase the service life of the bearing dramatically in these situations.”

Dave Healey, who is the Sales Engineer for NSK, concurs.

“Stopping water ingress into the rolling elements is extremely important for the longevity of the bearing life. It only takes a small amount of water or moisture to exact damage to the grease and bearing surfaces,” he explains. “Moreover, when grease is contaminated with water, the lubrication can soften and leak out. It also causes corrosion in the bearing raceways.”

The NSK triple sealed bearings have several advantages over a standard bearing that translate to extended bearing life. Their optimal design – which is specialised through hardened steel – ensures longevity, as do unique features such as the steel-balled setscrew.

“The steel-ball setscrew is a built-in feature that prevents loosening, even if the bearing is subjected to intense vibrations under heavy loads,” says Healey. “Our galvanised steel plate on the three seals also contributes to enhanced pressure resistance and corrosion resistance.”

To illustrate his point, Healey referred to research testing that NSK carried out with their triple sealed bearing and three other equivalent bearings of different manufacture. This involved 200 cubic centimetres of muddy water being poured in a cylindrical housing where the bearing being tested was installed. The bearing and propeller in front of the bearing were rotated at 500 rpm by a drive belt with a vibration of 0.6G applied to the housing. This ‘Muddy Water Resistance Test’ found that the life of the NSK triple sealed bearing was at least twice that of any other bearing in the test group1.

Tormey reiterated the impressive performance of NSK bearings, saying that their triple lip seal bearings had a prolonged service life of at least “60% more than comparable bearings.”

However, Tormey notes that this is dependent on how maintenance is performed.

“Maintenance procedures will absolutely affect the bearing life. This starts with how the bearings have been installed and then how they are greased.”

In terms of ensuring that the NSK bearings are the right fit for the job, and that the correct maintenance procedures are in place, Tormey says the relationship that BSC has with the customer as well as with NSK is critical.

“We can provide them with the right advice as well as the services to ensure they’re properly set up to work at their optimum,” Tormey explains.

Healey also highlights the importance of the relationship between NSK and BSC.

“We maintain a great working relationship that brings a lot of benefit to the customer. BSC see us as a ‘localised’ company. Our stock is based here and available, it doesn’t come via a third party warehouse or overseas. Importantly – and this is a critical difference to what BSC provide to customers – is that we give them full access. In other words, our stock is their stock,” explains Healey. “We often work with BSC jointly to provide services and onsite visits with customers. Along with their BSC’s engineering staff, we’re available 24/7.”

Tormey echoes these points, noting that the BSC account managers are in touch with NSK on a weekly basis.

“We share a great relationship, with engineers from both companies working jointly to deliver the best solutions to our customers,” says Tormey.

In terms of water and wastewater applications, Tormey further emphasizes BSC’s access to stock, around the clock availability and branch presence as peerless benefits to customers.

“Having the expertise to perform installations – especially in hard to install rotating equipment that is inherent to the water and wastewater segment – is very important,” he says. “This will ensure that a customer gets the best performance. With the NSK triple lip seal bearing, they’re going to get a better service life, but with the right installation and best maintenance practice, they can achieve a performance that is more than double that of the longevity of similar bearings.”

Key Features of NSK Triple Lip Sealed Bearings

  • Better waterproofing ensures longer life – these bearings feature a secure bearing seal with three lips. That’s three layers of protection against foul water.
  • Reduced maintenance costs – longer bearing life, means extended maintenance intervals.
  • Reduced equipment costs – by replacing conventional bearings, the overall total cost is reduced as the machinery performs better and the components don’t need to be replaced frequently.
  • Secure balled setscrew – provides much greater resistance against loosening due to vibration or impact.
  • Interchangeability – conforms to the Japanese Industrial Standard for UC-type bearings, serving as a ready replacement to existing bearing units. This NSK bearing is not only ready to use as a relubricable bearing, but can replace conventional bearing units of NSK as well as the bearings of other manufacturers.

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Reference

  1. Triple-Sealed Bearings for Ball Bearing Units, NSK Brochure: https://www.nsk.com/common/data/ctrgPdf/e1234a.pdf