10. 5. 2012Wear damage and particle formation in roller bearings - the final stage in a preventable process
Turbine and gearbox damage from abrasive wear in roller bearing raceways is the end result of a series of events. A full understanding of this process can lead to the identification of parameters to monitor these damage states at the earliest stage.
That is where the new WearSens® from cmc Instruments GmbH comes in. Early detection potential damage states - before the damage occurs.
According to academic papers, the start of the process is hairline crack formation in the raceway. This can be initiated by a number of different factors, too much load, turbine imbalance, transmitted vibration and simply the passage of roller bearings over time.
Once the hairline crack develops, oil then enters this crack, localised heat and vibration within the crack cause it to degrade into acids and hydrogen, inter alia. The hydrogen then causes embrittlement of the surface around the crack leading to shearing of particles, pitting of the roller bearing and subsequent damage. The work of the additives in the oil, though not instantaneous, will mask this deterioration to some extent. Corroded bearings, sheared particles and oil quality deterioration then contribute further to the damage.
Vibration monitoring and particle measurement are two technologies commonly used. Vibration monitoring is unable to distinguish change while the additives are doing their job, whilst particle measurement only works after damage occurs.
WearSens® was developed in conjunction German universities and will detect these changes long before damage occurs. It is a unique condition monitor, online and continuous. WearSens® can be used to optimise load versus damage, accurately show additive consumption and predict the need for timely preventative maintenance instead of rigid inspection intervals. Savings result from reduced downtime, accurate oil changes and reduction in abrasive wear.
A full understanding of the process that leads to abrasive wear damage allowed cmc Instruments to develop the WearSens® sensor system. To learn more about the process of abrasive wear in roller bearing raceways the cmc Instruments website has a FREE download of a paper, Tribological Aspects of Roller Bearing Failures by Prof. Dr. rer. nat. habil. Jürgen Gegner, SKF GmbH, Department of Material Physics, Institute of Material Science, University of Siegen.
WearSens® is easy to install or retro-fit with a choice of inline or flow through measurement. The decentralised, web based monitoring system makes results available anywhere in the world.
Applications for the WearSens® include wind turbines, industrial compressor systems, large gearboxes and lubricant analysis in automotive and marine test benches.
cmc Instruments manufacture trace moisture analysers, nitrogen generators for LC-MS applications, filter systems for process gases and the new WearSens® and OilQSens® - patented, online systems for condition monitoring in roller bearings, gears and transformers.