New benchmark for rotary seals

Walkersele Ultraglide is a new high-efficiency rotary lip seal aimed to meet the low-maintenance demands of hardworking industrial plant.

Ultraglide’s success is based on a new hydrogenated nitrile (HNBR) compound, developed by the James Walker Technology Centre for lip seals that run for long periods under hot, abrasive conditions.

As plant operators demand higher shaft speeds and working temperatures, plus extended maintenance-free life, the limiting factors are often bearing and bearing seal technology.

Explained material engineering manager Phil Embury: ‘Rotary seals based on conventional nitrile (NBR) rubber suffer lip hardening and cracking at high running speeds when under-lip temperatures reach around 100°C.’

‘Although fluoroelastomer (FKM) compounds can survive 200°C, they have poor wear resistance and limited physical strength at high temperatures. These compounds are also more expensive to produce and mould.’

James Walker’s new HNBR material has been formulated to overcome all these problems.

It withstands under-lip temperatures in excess of 150°C. Extended life and improved high speed running are achieved by the material’s low coefficient of friction (0.25) and superior heat dissipation properties.

‘We developed Walkersele Ultraglide with rolling mills and other heavy transmission systems in mind’, confirms David Edwin-Scott, James Walker’s technical manager

‘We also see great potential for it on rotary process plant in abrasive environments.’

He reports that trials on hot steel mill bearings in Germany have exceeded expectations.

‘Previous seals on this mill failed after a few weeks due to high under-lip temperatures and water contamination of the grease.’

‘Walkersele Ultraglide seals have now run seven months without noticeable loss of performance or integrity.’

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