Ultrasound detectors designed with the right technology and software can be used for condition monitoring and predictive maintenance. This will minimize production downtime, improve quality control and safety, and decrease man-hours by improving troubleshooting capabilities.
Using ultrasound detectors for leak detection is a growing industry standard. Ultrasonic leak detection is recommended by many, such as the U.S. Department of Energy1 , as the best method for detecting the location of leaks in order to minimize energy waste and improve plant efficiency. However, there are many cheap alternatives now available, most of which do not achieve desired results of 20-50% reduction in energy consumption of compressors. The inability of most detectors to diagnose mechanical equipment for early signs wear and lubrication issues is even more troublesome than a failure to quickly indicate and locate leaks is.
Consider the following summary from NAVSEA’s evaluation team for the integration of CTRL’s ultrasound detectors to the United States Navy in 2003:
More than 100 applications were identified in use for various equipment at each site such as boilers, heat exchangers, compressors, motors, pumps, valves, and steam traps
The total savings for the organization would be approximately $3.7 million annually
The return on investment for the integration of ultrasound with this cost avoidance would be approximately 15:1
The annual man-year savings caused by the reduction of time spent diagnosing and troubleshooting would be approximately 45 man-years
Actual savings by the U.S. Navy are much higher, given the rising costs of maintenance, fuel, and service. The U.S. Navy, like many commercial organizations, works with CTRL Systems, Inc. to implement ultrasound technology for predictive maintenance programs to decrease production and operation costs. This paper shall discuss ways to use ultrasonic technology for a fast and effective return on investment.
Condition based monitoring and predictive maintenance has traditionally been performed through vibration analysis, shock pulse, infrared, and other technologies. Ultrasound technology is often ignored but is an excellent option, especially for organizations without the luxury of large budgets or trained, certified personnel. The CTRL UL101 ultrasound detector is capable of accurately interpreting the sounds created by under lubrication, over lubrication, and early signs of wear. The right ultrasound technology is a fast and effective means of determining such conditions in moving, mechanical components such as bearings, gearboxes, motors, compressors, etc.
Ultrasound is produced by friction, impact, turbulence, and electrical discharge. Friction and impact are the by-products of mechanical equipment. For example, a roller bearing will produce friction as the shaft and balls roll around the center. If there is too much friction, however, problems begin to occur on the production line due to imbalance, or the bearing might seize, thereby shutting down production altogether.
Proper lubrication of critical bearings is important at all times. A properly lubricated bearing will produce a smooth rolling ultrasound, detectable by the CTRL UL101 ultrasound receiver, which is placed in contact with the bearing or gearbox housing.
If the bearing is over-lubricated, very little ultrasound will be heard through the headset. If the bearing is under-lubricated, the intensity of the bearing will increase dramatically and other sounds will be inherent such as fluttering or scratchiness. Indications of an under lubricated bearing will appear in ultrasound even before infrared can detect heat increases and well in advance of vibration analysis.
In addition, once a bearing begins to wear, the ultrasound wave will produce large spikes in the signal caused by bearing defects. The spikes are heard as pops through the headset and are very noticeable relative to the normal sounds of a new, properly lubricated bearing. Once the ultrasound produced by the bearing begins to indicate these characteristics, the replacement of the bearing can be planned during normal production shutdown. The detection of wear is instantaneous. It is not necessary to take readings of the bearing from several points of contact along different axes and send the readings away for analysis.