From the editor's desk: Prescriptive maintenance drives top performance
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2017, News
The interconnectedness of the IIoT has changed the traditional inspection-based approach to plant maintenance, repair and overhaul (MRO). But, since every plant is still different, their MRO requirements will also still be different. This Industry Guide serves as a reference point to the many different approaches and technologies that are now available for equipment condition monitoring and the concepts of reliability centred maintenance. We hope there are ideas in here that may help to solve a problem you could be struggling with in your own particular plant.
The objective remains to keep the plant running at optimal efficiency, but now secure in the knowledge that a breakdown is not about to happen suddenly and with no warning. The answer lies in the techniques of continuous data harvesting, followed by information analysis performed against a known ‘healthy’ digital signature of that particular equipment. Any significant difference triggers an early warning of deterioration, giving ample time to switch over to a standby, pump for arguments sake, while the primary is taken out of service for repair.
The question for the maintenance manager now is which plant operations would benefit the most from continuous monitoring? Or in other words, which equipment is most critical to overall business effectiveness?
Once the crucial areas have been identified, then the decision must be taken as to whether the monitoring can be achieved via the plant’s current automation platforms, or whether it has to be separate. Once this is known, it must then be decided whether the systems can be run and managed in-house, or whether it makes better business sense to outsource this to a specialist third-party service operation, which taps into the facility through a (hopefully) secure Internet connection.
What are the options?
For some of the obvious problems that occur across most large plants, no matter what the specific industry might be, many suppliers have a range of off-the-shelf solutions available. Monitoring of steam traps or compressed airlines are good examples, since leaks on either can become costly over time. Ultrasonic sensors are available to detect jammed or leaking steam traps, and their built-in wireless transmitters eliminate the need for lengthy retrofit cable runs around the facility. Often these are fitted with a temperature sensor as well, and when both the noise and temperature levels rise synchronously, a warning is sent over the wireless network to the control room identifying the exact location of the leak. (See ‘Compressed air leak detection and quality management’ for more on ultrasonic leak detection for compressed air lines.)
Another area where advance warning of wear problems is a benefit is in the condition of bearings on heavy duty rotating machinery like pumps, fans and centrifuges. With a sensor on the outside of the bearing housing, any abnormal vibration velocity can indicate shaft bearing deterioration. The bearing manufacturers themselves, such as SKF, provide simple alarm systems, as well as multi-sensor monitoring for large pieces of equipment like wind turbines, all backed by their bearing know-how. Some machines might deserve continuous monitoring, but there are also wireless (self-powered) versions of these sensors that can be moved around the plant as necessary. (See ‘SKF Life Cycle Management’ for more on SKF’s approach to effective asset management.)
Today’s condition monitoring systems combined with the most advanced analytics packages ever devised, enable industrial organisations to implement new, more effective maintenance strategies that advance them from the preventative and reactive strategies of the past, to modern condition-based prescriptive maintenance on demand, and only when required.
According to the ARC Advisory Group’s Ralph Rio (‘Advanced maintenance maturity model increases reliability, reduces costs’), “Higher levels of maintenance maturity yield business benefits that go beyond just reducing the cost of the maintenance itself. These include improvements in on-time shipments, customer satisfaction, quality and production yield, safety, work-in-progress inventory, and ultimately, revenue generation.”
Whatever the unique requirements of your plant, we trust the extensive list of suppliers and services at the end of this publication will help you to identify the right partner for an MRO strategy that moves your organisation closer to top quartile performance and the benefits that accrue to those at the top of the pile.
Editor: SA Instrumentation & Control