Focus on Coal
SRB split bearings also offer the benefit that they can be inspected in situ as part of a planned maintenance schedule; and have a longer life span because they cannot be crosslocated. In addition to being easier to fit, inspect and maintain than solid bearings, Revolvo’s SRB split roller bearings are providing Hatfield Colliery with the highest levels of reliability, due to the performance of their sealing systems. Te design of Revolvo’s SRB bearings means that
they perform exceptionally well in harsh operating conditions, even with shaft misalignment. With SRB split bearings, the spherical location between the housing and pedestal support ensures that even under conditions of shaft misalignment, the seal will always remain concentric to the shaft. In contrast, solid mounted roller bearings under conditions of misalignment can suffer from non-concentric ineffective seals that will rapidly lead to premature and expensive bearing failure. Revolvo has taken this design advantage forward
and developed many designs of high performance seals, which provide effective sealing even in the worst operating environments – even under water. Te excellent performance of their labyrinth seals is evidenced by am recent application where Revolvo solved a major problem of premature wear on screw conveyor bearings in the cement industry. With its many new design features, Revolvo’s range of SRB split roller bearings meets and surpasses all the demands of traditional users in process industries, and also those of users in new industries. Manufactured in Dudley, in the West Midlands, in a plant that is benefiting from over £1.5 million of investment in new machinery, the range is available in Light, Medium and Heavy series in sizes from 35mm to 600mm diameter, plus Imperial equivalents, and larger non-catalogue sizes up to 1500mm in outside diameter. It is fully interchangeable with competitive products on the market.
Long life grease Meanwhile, by employing a programme of material substitution and longer life lubrication technology, a wind turbine manufacturer was able to achieve maintenance cost-savings. Te manufacturer of micro wind turbines had been experiencing problems due to the prohibitive cost of bearings. Te manufacturer was facing a stark choice: improve the purchasing and manufacturing costs for the project, or it would not continue. NSK engineer visited the customer to review the
machine design. Tis highlighted several areas where unit build cost could be reduced substantially. Following the visit, a supporting design justification report, and bearing and grease life calculations were produced. Tese not only underpinned the design cost
reductions, but also promised benefits such as simplified assembly procedures, and improvements in overall bearing performance, reliability, and bearing life.
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www.engineerlive.com
Te customer acted upon NSK’s recommendations; substituting NSK premium brand single row radial ball bearings, where before there had been a selection of mixed brand products, including single row radial ball bearings and angular contact bearings. Te NSK bearings are lubricated by NSK’s long
life grease, which delivers a grease life of over 200 000 hours compared with a grease life of 22 400 hours for the mixed brand bearing package. Tis improvement in grease life has enabled major
reductions in maintenance to be achieved, helping to keep the micro turbine in service substantially longer. Te quantification of this improvement, in conjunction with the additional improvements gained from the NSK package, has been calculated by the customer to exceed €337 000. Moreover, the manufacturer is also benefiting
from extended product life, improved reliability and reduced maintenance, as a result of replacing mixed brand bearing products with NSK’s premium brand bearings and longlife grease. NSK is producing similar cost
saving results across all industry sectors. Te company’s cost saving programme looks at all aspects of bearing systems: design, specific problem applications, lubrication, and even training issues. Te process often starts with a site survey, which is
very detailed. NSK engineers visit a customer’s premises, talk to them and get to understand what the difficulty is. Data acquired from the visit is subsequently analysed, leading to recommendations for improvements. Tese improvements are then quantified in cost terms, demonstrating the level of savings that can be expected by the customer as a result of adopting the solution proposed by NSK. l
For more information, visit
www.nskeurope.com
Fig. 2. SRB Split Roller Bearings from UK manufacturer, Revolvo Ltd, are playing a major role in the operation of the recently reopened Hatfield Colliery near Doncaster, UK.
Fig. 3. The SRB heavy duty 240 mm split bearing units are used on underground coal handling conveyors, due to their inherent ability to be replaced quickly around 90 per cent faster than solid bearings – and their superior sealing system, which optimises bearing life in the harsh mining environment.
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