The use of laser etched seal faces to extend seal performance and improve reliability

摘要

The use of structures on seal faces to extend the operating envelope of mechanical seals is well documented. Until now however, structures, whilst improving seal face lubrication has also led to increasing seal leakage. 'Laserface' is a patented technique which, by using two distinctly different structures, substantially extends the capability of mechanical seals without the associated increase in leakage. The services which benefit from 'Laserface' are wide ranging, and one area where it is particularly suited is hot water sealing. Hot water presents a difficult sealing service for two main reasons; the low viscosity of the fluid at high temperature results in poor lubrication properties, and, to maximise efficiency, it is usually pumped close to its vapour pressure. As a consequence, seals can suffer from vaporisation and high wear rates. To ensure a stable fluid film between the seal faces, some form of external product cooling is often required which besides adding cost to the initial seal installation, introduces significant maintenance and operating costs. The simple replacement of a plain seal face with a 'Laserface', extends the performance envelope of general purpose seals to such an extent that the need for expensive cooling can be eliminated providing a reliable sealing solution without any increase in leakage.