What’s Your Oil Telling You?
EP Editorial Staff | March 16, 2018
Paying attention to what lubricants ‘say’ can protect equipment from catastrophic failure.
In an environment where equipment is expected to run continuously under extreme operating conditions, its failure can bring production to a halt. One important aspect of ensuring that machines run optimally is proper lubrication management.
Effective lubrication of critical equipment involves more than just changing or topping off oil on a regular basis, however. To ensure maximum uptime and efficiency, it’s necessary to understand the problems indicated in your oil. Oil analysis and intelligence predict lubrication problems and address them before a catastrophic failure occurs.
PREDICTION VS. PREVENTION
Traditional maintenance has involved time-based preventive activities in which lubricants are changed and equipment is tested after a set amount of time. Like a regular oil change and tune-up on a car, this level of maintenance assumes systems are running properly and there’s no apparent concern for a failure.
To find and fix problems before failure occurs, predictive maintenance (PdM) considers oil condition to determine when to perform an activity. Traditionally, monitoring and testing has been through thermography (looking for heat signals and hot spots) or vibration analysis to signal unwanted friction, wear, and inefficiency. While these technologies have been well accepted in industry, they’re not effective until an issue has already started.
As described below, oil analysis and intelligence are effective techniques that look at preemptive conditions around lubricant and machine conditions. Changes in key indicators of the oil chemistry show characteristics that reveal trouble before it actually becomes an issue for a piece of equipment.
FTIR: Today’s most advanced technique for oil analysis is Fourier-transform infrared spectroscopy (FTIR), which uses infrared light to scan samples and measure chemical properties. FTIR detects common contaminants and byproducts of lubricant degradation (antioxidants, water, soot, fuel, glycol, and oxidation) and additives in oil. The presence of these properties can provide important information (Fig. 1). For example:
• A high water level in oil causes hydrolysis, which forms destructive acids that cause permanent degradation of the oil, rust in the machine, and, sometimes, total equipment failure.
• The presence of glycol in petroleum indicates a seal breach in the system.
• Metal contaminants reveal critical bearing wear.
Lubricant intelligence: While oil-test data is important, it means nothing if you don’t know how to apply that information into something meaningful and actionable. It would be like a doctor handing you an EKG chart or an MRI scan and sending you home to figure it out. An expert’s interpretation of the results and recommended fixes makes oil analysis a true PdM process (see Sidebar above, for example).
Reading oil-analysis data is much like looking at the night sky: An untrained eye will just see stars, but a trained astronomer can explain what those stars mean and how they fit into a bigger picture of constellations. Similarly, oil experts can explain what analysis figures mean and the impact they have on equipment performance. This level of oil intelligence helps see the condition of oil and equipment without a shutdown. Analysts can detect failures in progress and point straight to the root cause, providing sufficient lead time to schedule corrective maintenance before catastrophic failure, with minimal disruption of operations.
The biggest cost of lubricant failure is downtime. If a line goes down because a bearing burned up, the best-case scenario is a four-hour replacement for two workers. Those four hours of lost production, as well as wasted product to get the equipment back online, can add up to a hefty price. Plus, in industries such as power generation, an operation could incur fines for no-starts.
THE ROLE OF SENSORS
Sensors are becoming an increasingly important tool in gathering real-time oil intelligence. As an example, consider constant-level-lubrication technology. When connected to a constant-level oiler, a sensor-based system can continuously measure levels and transmit the information wirelessly to a simple dashboard viewable from a personal computer or smart phone.
Knowing the oil level and trending its data can prevent a catastrophic event. For example, if oil remains the same level for a long period, the bearing could be starved, and, in turn, burn out. Or, an oil level that drops quickly could suggest a blown seal that needs immediate attention. In only minutes, a manager can check the dashboard, look at oil levels and trends for all machines, and deploy a technician to replace oil or make a needed repair.
NOW AND BEYOND
Keep in mind that lubricants can tell you a lot about what’s wrong (or going wrong) with your equipment. With today’s state-of-the-art testing, analysis, and expert advice, you can clearly understand what your lubricants are saying. Going forward, lubricant intelligence and monitoring devices will continue to evolve and, as a result, provide ever-more valuable data for plant-
maintenance efforts. EP
Delivering Diagnostics and More
External factors can have a big impact on oil conditions. Thus, it’s important to establish a relationship with a lubrication-analysis lab that knows your business and can provide relevant diagnostics. Such was the case with a company seeking assistance from oil-intelligence experts to find the reason for chronic filter problems in a turbine that was causing unplanned downtime.
After reviewing the FTIR chart in Fig. 2 indicating high levels of zinc and calcium, and then asking additional questions about the plant’s operations, the experts pinpointed the source of the problem: Calcium in the environment was contaminating the oil and changing to calcium carbonate, causing rust and clogging the filter (Fig. 3). Beyond that, the experts noticed the customer was using the wrong lubricant and suggested an alternative.
Information in this article was provided by Jim Jung, CLS, of Trico Corp., Pewaukee, WI. For more information, go to tricocorp.com.