Posted to News on 19th Jul 2018, 00:00
Conditioned reaction
The word ‘maintenance’ implies keeping things as they are, preserving the current state of affairs, retaining the status quo, more of the same, continuing along similar lines. The implication is that maintenance is a fixed pursuit that offers no room for improvement. This is wrong on two levels. First, it’s always possible to boost the performance of a maintenance regime. Indeed, it should be seen as critical in every factory’s continuous improvement cycle. Secondly, streamlining maintenance can lead to big improvements in the production process, huge savings, better consistency and increased reliability.
One form of predictive maintenance – condition monitoring, also called condition-based maintenance – is particularly effective in this regard. It is a surprise therefore that too many companies fail to recognise its significant benefits. CBM is maintenance that is performed when need arises, typically after one or more indicators show that equipment is going to fail or that equipment performance is deteriorating. Successfully using this programme enables the repair of problem components before failure. Condition monitoring not only helps plant personnel reduce the possibility of catastrophic failure, but also allows them to order parts in advance, schedule manpower, and plan other repairs during the downtime.
CBM 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 the costs of implementation. SKF adopts a three-tiered approach to CBM – basic, better or best – which serves a variety of circumstances and machine conditions, and enables users to choose a level suited to their needs in terms of operating assets more dependably, affordably, productively and profitably.
- Basic – This typically employs simple vibration and temperature monitoring tools commonly used by maintenance technicians on routine walk-through inspections such as handheld devices like the SKF QuickCollect, which monitors both vibration and temperature, transmitting this data wirelessly to a mobile device, where an entry-level app provides instant machine diagnostics and analysis.
Readings taken by these devices can be transmitted via Bluetooth to a smartphone or tablet running an entry-level app which collects, stores and shares machine health data. Users are able to 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.
Alternatively, Basic CBM can make use of permanently installed sensors equipped with LEDs to provide an at-a-glance indication of machine health that measure changes in vibration and operating temperatures in mechanical and electrical systems. After all, operators work in close proximity to equipment and are usually the first to detect slight changes in process conditions and machinery health.
- Better – This level ensures that valuable machine health data provided by experienced staff is more easily collected and analysed. 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.
Asset care might involve the installation of fixed, multi-channel machine health monitoring systems located in a central control cabinet or alongside the monitored machine. These systems can store large amounts of data, which are accessed via a fieldbus connection for remote analysis. SKF’s Operator Driven Reliability programme is an example of the better approach. An app for the SKF QuickCollect platform called SKF DataCollect also allows access to SKF’s remote expert services. Should a more permanent installation be wanted, then the SKF Multilog On-line System IMx-8 would be a suitable choice.
- Best – This involves taking asset and machine health monitoring online. Data from permanently installed sensors (hardwired back to junction boxes or connected wirelessly) are transmitted via a secure internet connection to a centralised computer system capable of advanced data analysis.
Online systems are typically 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 distributed control system for trending, alarm and machine shutdown purposes.
Protection systems offer real-time remote monitoring of critical machinery to provide a rapid and safe machine shutdown rather than periodic data collection.
At the best level, the SKF Multilog On-line System IMx-M system can be used in conjunction with the company’s @ptitude monitoring software suite to provide a complete system for the initiation of machinery shutdown, early fault detection and diagnosis, and is particularly suited to remotely located critical assets.
