Using Ultrasound for Condition Monitoring

Tim Goshert

In the past decade, the capabilities of many condition-based assessment tools, sometimes called predictive technologies, have significantly expanded. The hardware has become more compact, more rugged and much easier to use. The companion software applications have become more powerful with exponentially increasing capabilities. Additionally, the software tools have become more mainstream with much less reliance on proprietary protocol and programming. This situation has led to expanded use of these sophisticated tools to monitor and assess equipment health. We have seen vibration analysis, oil analysis, infrared, motor circuit analysis and many other non-destructive tools become very popular. Many organizations now stress their use as a prominent part of the maintenance and reliability programs.

As Reliability Centered Maintenance (RCM) theory points out, it is important for an organization to use multiple predictive technologies in a program. The type and how much of each predictive technology used directly depends on what the organization’s critical equipment is, how this critical equipment fails, what the failure consequences are, and finally what technologies will proactively detect this defect early before catastrophic failure occurs.

With all that being said, I have come to admire the capabilities and financial return to an organization of one specific type of these predictive technologies. I have seen in the past decade that one of the simplest, easiest to learn and, coincidently, the most underrated technology gives an organization or facility a great return for the investment. The problem has been that it sometimes gets ignored, in my opinion.

One of my all-time favorite comedians is Rodney Dangerfield. His moniker and tag line was that he “gets no respect.” Rodney is no longer with us, but his comedy routines will live into eternity. As his memory lives on, certainly many in the world now give Rodney the respect as a genius of comedy.

I think there is a predictive technology that typically “gets no respect” because of its simplicity, ease of use and low investment cost. It is airborne and structure-borne ultrasound technology. I have labeled airborne and structure-borne ultrasound as the Rodney Dangerfield of predictive technologies. It just gets little to no respect.

Years ago after having significant training in this predictive technology from Mark Goodman, Gary Mohr and Doug Waetjen from UE Systems, I became aware of ultrasound’s versatility of applications, ability to detect failure modes on many of our critical pieces of equipment, ease of use and, most importantly, its significant return on the tool’s investment.

Airborne and structure-borne capabilities are varied. I would categorize the three major application areas as:

1. Compressed air/gas leak detection for energy conservation
In today’s economic conditions, it is critical to eliminate waste by locating and correcting costly leaks of compressed air and specialty gasses. An added benefit of correcting compressed air leaks is the reduction of greenhouse gas emissions that are the result of the electricity savings associated with the leaks. Both cost savings and greenhouse gas reductions can be measured, documented and reported using the software that comes with the ultrasonic detectors.

2. Bearing monitoring for condition-based lubrication and slower-speed bearings
One of the biggest contributing factors to bearing failure is overlubrication. Ultrasonic technology can identify which bearings need to be lubricated and then ensure that the bearings are not overlubricated. Software allows us to report and document these issues.

3. Electrical inspection, especially enclosed switchgear for safety issues
Ultrasound can be used to scan enclosed switchgear while it is energized to determine if there is corona, tracking or arcing before opening the switchgear to inspect visually or with infrared. By scanning first with ultrasound, you eliminate the risk of opening the cabinet “blind” and being exposed to an arc flash situation.

I have witnessed ultrasound technology’s ability to detect defects in critical equipment in our Cargill facilities. I have seen the tool’s payback completely in its first use on an air survey. We have experienced this at many facilities. After one air survey, we identified air leaks that - after we fixed the leaks - saved us three times the initial investment of the tool in one year. This was only looking at one basic application of ultrasound. After additional training of our people on further applications, we continue to identify defects when corrected, saving us energy, plant downtime and operating cost.

Therefore, I would highly recommend all maintenance and reliability programs to concentrate on initiating or expanding airborne and structure-borne ultrasound use in your plant. Please remember the Rodney Dangerfield of predictive technologies. Give ultrasound some respect and please apply its use in your facilities.

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