Just as advances in medicine have more than doubled human life expectancy, the application of reliability technology to maintenance has brought similar results to industry. The similarities are remarkable. For example, think of blood testing and oil analysis, or ultrasonic testing for heart valve leakage and ultrasonic surveys for steam/air leaks.
The practice of medicine (I always wondered why we say that Medical Doctors “practice” medicine) has resulted in a significant increase in life expectancy. Much of this increase is due to the ability to diagnose illness and disease at early stages of development and take appropriate action.
If we in the maintenance field apply a similar proactive approach, can we not expect a corresponding increase in the life expectancy of our plant machinery? Recent experience in multiple industries shouts YES! Let’s look at some of the parallels between medical diagnostic testing and industrial predictive technologies.
- Temperature Measurements
One of the first medical diagnostic tests was the measurement of body temperature. Elevated body temperature is a primary indicator of infection. Likewise, elevated bearing temperature is a strong indicator of damage to the bearings or poor lubrication; and higher than normal temperatures in electrical circuits can indicate immanent failure.
- Ultrasonic Testing
Ultrasound tests are performed routinely to look for abnormalities during pregnancy or find tumors without resorting to surgery. Ultrasonic testing is used in industry to: detect air and steam leaks; determine flow; detect tank and pipe wall thickness; detect roller bearing damage and corona discharge in electrical circuits.
- Electrocardiogram (EKG) and Vibration Analysis
An electrocardiogram is a noninvasive test used to monitor your heart. Vibration analysis is also a noninvasive test that seeks to determine the mechanical condition of various components in rotating machinery. Some of the problems that can be detected are:
- Bearing race/roller defects
- Flow (process) related
- Electric motor related
- Blood Testing and Oil Testing
Blood testing is used to detect a broad spectrum medical conditions and can determine the “quality” of the blood and the presence of foreign substances.
Oil testing can determine if the lubricant has a lower than desired quantity of a substance — in which case an additive may be prescribed. If high levels of contamination are found, filtering may be recommended.
- Electromyogram (EMG) and Modal Analysis
An EMG measures the electrical activity of muscles at rest and during contraction. Modal analysis cross-channel vibration tests measure the phase delay between an input force and the resultant vibration motion.
In medicine, X-rays pinpoint breaks and fractures. In industry, x-rays are used to detect cracks in shafts, piping and structure.
- Blood pressure.
In medicine, blood pressure measures the pressure in blood vessels and can detect heart damage. In industry, the measurement of the suction pressure and discharge pressure on pumps, compressors and blowers can determine if the machine is “pumping” efficiently.
Anyone working in the predictive field for even a short time knows that once a defect is reported, the next question is “How long will it last?” A good place to start is by contacting HECO.
When you tell HECO you’re having a problem with an electric motor, we want to find out why and make sure it doesn’t happen again. Predictive maintenance is a big part of that, and is integral to our systems approach of optimizing the entire electric motor powertrain.
In the meantime, please download the free eBook, Reliability Maintenance is Good Medicine.
About the Author:
Tom Spettel is a Sr. Engineer at HECO. He is an ANSI/ISO Certified, Category IV Vibration Analyst. Before joining HECO, Tom was an US Army Medical Specialist, running diagnostic tests for a MASH unit in Vietnam. He then worked in a chemical plant/refinery supervising annual teardown inspections on large steam turbines, compressors, and pumps. Later, he became a vibration analyst, where he saw the similarities to previous medical job.