Six years seals John Crane reputation

27 March 2008

When the Domtar mill in Canada undertook a scheduled maintenance shutdown, engineers were pleasantly surprised to find a seal, that had provided six years of service, was virtually unworn. Supplied by Slough, UK, headquartered manufacturer, John Crane, the seal, fitted to a large pressure screen, was removed as a preventative maintenance measure.

John Crane seal was removed from operation with seal faces hardly worn
John Crane seal was removed from operation with seal faces hardly worn

The paper plant in Dryden, Ontario, produces uncoated free-sheet paper. In 2001 the mill installed a Valmet TLA-1800 pressure screen to feed stock to its paper machine. A John Crane Safematic SAF 230 TREN seal was fitted to a 230mm diameter shaft which serves this screen. The seal was required to handle a rotation speed of 92.4 r.p.m and a pressure of 323 Kpa for six years.

A constant supply of water is required to lubricate and cool the seal. This is drawn from the nearby Wabigoon River and passes through a Safematic Safefilter system before being piped into a Safeunit SFD 08 10 – AC-1 which controls the flow to the double seal as well as the back pressure in the seal chamber. After lubricating the seal faces and dissipating heat the water flows back to the Safeunit before being piped away to drain.

After the discovery Harold Nelles, John Crane’s regional manager for Winnipeg and Manitoba said it was an example of the value built-in to John Crane Safematic products. He said: ‘The experience of industries such as pulp and paper allows John Crane Safematic to create products and solutions that are individually tailored to both the specific application and the individual customer and that results in the sort of outstanding reliability that this case displays.

‘It also demonstrated the additional benefits that John Crane Safematic products provide when they are combined to create a genuinely integrated system.’

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