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Gearboxes: water contamination problems
June 1, 2008 By: Pit and Quarry Staff Pit & QuarryDangers of water contamination in gearboxes
Just 1 percent of water in industrial gear oil can reduce bearing life by up to 90 percent, which can have significant cost implications in terms of both component costs and potential unscheduled downtime. While awareness of the problems that water contamination can cause is strong, operators are often surprised to learn how quickly contamination can escalate and the level of damage that can be caused by just a small amount.
As water is an inherent part of many production processes, removing the potential for contamination is simply not practical. However, it is possible to manage the contamination issue to help prevent it from becoming a serious problem.
Good maintenance practice and the careful selection of a gear oil that quickly separates from water is by far the most effective way of reducing the risk of serious component failure and unscheduled downtime caused by water contamination.
Gear oil with improved water separation properties not only allows faster and easier water draining, but also lessens the frequency of oil changes. As a result, the operator can benefit both operationally and financially from reduced downtime and lower oil consumption.
In the real world, protecting gears from water contamination completely is often a losing battle for operators; exposure to the elements, cleaning practices, leaking heat exchangers, process water and condensation resulting from variable operating temperatures can all be contributory factors to water contamination.
There are process improvements that can be made, but the risk factors need to be identified first and any changes in production process may come at an inevitable cost, from either capital outlay or implementation – or both.
The important thing is to identify potential contamination points as early as possible and take steps both to rectify the risk factors and counteract the effects of the problem. In short, the most effective strategy is to combine measures to prevent water entering the system with measures that limit the water's capacity for damaging components.
Even the most vigilant maintenance team may not be aware that there is a serious water contamination problem until, for example, corrosion and fatigue failure has started to occur. Symptoms are often slow to emerge, and by the time pitting and surface wear begin to appear, components may already need urgent replacement, requiring downtime and potentially a disruption in production.
Vibration analysis and oil condition monitoring can help to act as an early warning system, and this should form part of an effective lubrication management program. These, however, are simply a valuable indicator that problems may be occurring, not a preventative measure.
One important way to help minimize the potential for water damage within the system is to choose a lubricant designed to maintain its performance even when small amounts of water enter the system. Protection from water contamination is just one of many factors that should be considered when specifying the best gear oil for an application, and it should be just one of the performance benefits a high-quality lubricant offers.
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