Predictive maintenance & condition monitoring

Condition monitoring technology has benefited from advances in connectivity and is also becoming cheaper to run. This has led to many operations teams spending less time collecting data than they used to. Here Ian Peverill at SKF, discusses the monitoring evolution that is taking place, how digitalisation is changing maintenance monitoring and the cost-reductions achieved thanks to wireless technology and new analytic approaches now available.

the reduced price of sensors, so the approach is now viable to even more manufacturers. Picking the right approach for any given asset,

however, is always a question of balancing the costs – of collecting, communicating, storing and analysing the data – against the reliability benefits that data delivers. In practice, at present, that means many organisations use permanently installed systems in their most critical assets and rely on handheld data collection for the rest. A gamechanger in data collection is that the cost of permanently installed data collection systems is coming down. In part, this is thanks to the development of robust, inexpensive sensors and processing electronics. More importantly, it is because connecting those sensors has become cheaper and easier to do. This matters because installation labour, along with dedicated cabling and communications hardware, can make up 60 to 75 per cent of the total cost of a permanent condition monitoring system.

ABILITY TO GO WIRELESS Today, companies have multiple options to reduce those costs. They can connect data acquisition devices directly to their existing wired networks. Or they can go wireless. Secure Wi-Fi networks are increasingly

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common in factories and other industrial facilities, for example. A new generation of low- power wireless “mesh” network technologies makes it possible to install sensors that can operate for years on battery power alone. The ease of deployment of such sensors is attractive, but the energy budget still needs that balance against the asset’s criticality and wired alternatives. However, the latest wireless condition monitoring systems are improving rotating equipment performance programmes on a scale that was previously widely considered to be uneconomical. This is being achieved by combining the knowledge gained on machine health monitoring over many decades, by established industrial businesses, with emerging and innovative network technology from connectivity specialists. One such example is SKF who has developed a

wireless condition monitoring system that can economically automate vibration data collection within its service contracts. With this solution, a mesh network protocol enables sensors to exchange data, navigating around obstacles, such as pipework and liquid storage tanks, instead of trying to punch through them. A cognitive co-existence technique scans the radio spectrum and switches frequencies to avoid ‘busy’ channels and overcome interference. All this means increased radio reliability and less effort, significantly reducing the demands on the battery in a small device. It minimises energy usage by knowing exactly when to switch itself on and off. This means it can work on a single battery for many years, in tough wireless environments such as paper mills. From a practical perspective there are many benefits. The self-forming sensor network

requires no existing infrastructure such as Wi-Fi, and can be deployed on a scale sufficient to cover the monitoring points of today’s “walk-arounds”. Predictive maintenance programmes can be expanded, with data captured more often, which increases defect detection rates and leads to avoidance of costly unplanned machine shutdowns. Advanced condition monitoring systems are also becoming cheaper to run, thanks to the development of new analytics approaches, such as the application of machine learning technologies. These methods are automating the interpretation of machine condition data to a much greater degree than was previously possible. That means companies can monitor more assets with fewer skilled analysts. Add to this the new technology that is changing the way machine condition data is used and the results of analyses are becoming far more accessible: a factory manager can now see the status of the facility at a glance on their phone. So, do all these advances in machine monitoring mean that the maintenance team can put an end to their regular maintenance walk arounds? Well, the answer is a definitive ‘no’. This is because no matter how advanced the technology becomes, machines still need people to maintain, diagnose and improve them. And when it comes to routine inspections, and root-cause problem solving in reliability, there is no substitute for a hands-on approach. Although tomorrow’s maintenance specialists will probably spend less of their time on routine checks and measurements, they will still be out on the factory floor, just undertaking more activities that deliver key performance and reliability improvements than ever before.


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