Condition-based asset care: A three-level approach

Both condition-based and predictive maintenance can take a variety of forms and the level of sophistication deemed necessary for a particular facility will be dictated by a host of factors, not least being the costs of implementation, the availability and skills levels of onsite maintenance staff and the impact of machine failure on personnel safety, profitability and downstream processes.

SKF has developed a staged approach to condition-based maintenance, with asset criticality defining which level of sophistication provided by each of these stages - ‘basic’, ‘better’ or ‘best’ – is most appropriate to a particular application. Whichever the choice, the solution should meet both current and future requirements, as well as being affordable to manage and easily expanded should this be needed at a later date. Let's take a look at each of these asset care stages in turn.

Basic

Where traditional methods of preventative maintenance can often lead to unnecessary machine inspections, condition-based maintenance identifies potential wear or faults as they develop, and thus allow more convenient maintenance scheduling. Basic condition based-maintenance makes use of handheld vibration and temperature monitoring tools, commonly used by maintenance technicians on routine walk-through inspections.

Readings taken by these devices may be transmitted via Bluetooth to a smartphone or tablet running an entry-level app that collects, stores and shares machine health data. Users can set their own alarm thresholds in the app or use the app’s stored machine condition profiles against which they can assess the condition of the machine under inspection. In addition to handheld devices, permanently installed sensors equipped with LEDs can be used to provide an at-a-glance indication of machine health.

Better

Experienced operators are more likely to use apps that extend the diagnostic capabilities of a handheld instrument, allowing them to manage and monitor their maintenance tasks and inspection data more effectively. These apps also enable measurements to be uploaded to a remote cloud server, which can be accessed later by the user for analysis on a desktop, or by remotely located experts should the user require a more professional assessment.

‘Better’ asset care often involves the installation of fixed, multi-channel machine health monitoring systems located either in a central control cabinet or alongside the monitored machine. These systems are capable of storing large amounts of data, which are accessed via a fieldbus connection for remote analysis.

Best

When handheld or periodic data collection instruments are deemed insufficient, the next step is to take asset and machine health monitoring online. In this case, data from permanently installed sensors - either hardwired back to junction boxes or connected wirelessly – will be routed via a secure internet connection to a centralised computer system that is capable of advanced data analysis.

Online systems are normally configured to provide either ‘surveillance’ or ‘protection’. Surveillance monitoring systems are often configured for periodic automated data collection using multi-channel, wireless or a series of single-channel transmitters. These can communicate directly with a PLC or DCS for trending, alarm and machine shutdown purposes. Protection systems, on the other hand, offer real-time remote monitoring of critical machinery to provide a rapid and safe machine shutdown rather than periodic data collection.

Whatever your business, if it has a manufacturing or process element, the optimised wellbeing of its mechanical assets should always be a key concern. Condition-based monitoring offers a well-proven route to achieving this goal; it is a critical management tool that can deliver real business benefits, not just in terms of plant reliability, but also productivity and ultimately your profitability.