Is Your Machine Headed For A Heart Attack?
EP Editorial Staff | February 1, 2022
Lubricant systems should receive the same care and maintenance as the human circulatory system.
By Mark Barnes, PhD, CMRP, Des-Case Corp.
It’s often said that the lubricant is the “lifeblood” of any machine, and with good reason. Without the correct oil maintained in a clean, healthy condition, few machines will function with optimum reliability. However, the parallel between an oil and the literal and figurative meaning of “lifeblood” as “the blood of life” goes far deeper than semantics.
The blood in our bodies plays a role in several critical functions including nutrition, respiration, waste control, temperature regulation, and disease prevention. So too, an oil does far more than lubricate moving surfaces. It also helps distribute vital additives throughout the system, serves to act as a heat sink, helps control contamination, and is a key indicator of machine health, making the comparison between the two compelling.
The human cardiovascular system comprises the heart, heart valves, arteries, veins, and capillaries. In the same way, a circulating lube oil system contains a pump, distribution valves, and supply and return lines. Not technically part of the cardiovascular system, our kidneys also play a crucial role in controlling contamination, just like the filters in a lube oil system. Any blockage, leakage, or failure in any one of the components that serve to transport blood or oil can have serious and often fatal consequences for either the body or the machine.
Blood comprises two primary constituents, plasma and red bloods cells, which make up more than 98% of blood along with white blood cells and platelets. While the concentration of white blood cells and platelets is low, if their functionality is impaired, significant health issues can ensue. Likewise, an oil is made up of two main components, base oil and additives. In most industrial fluids, the base oil makes up 80% to 95% of the lubricant volume. However, without the correct additive composition, machine life will be significantly reduced.
While two blood samples or two oil samples may look the same, they may not necessarily function the same. There are four main blood types: A, B, AB, and O. Similarly, there are four main types of industrial oils: rust and oxidation inhibiters (R&O), antiwear (AW), extreme pressure (EP), and compounded (COMP). Just as giving blood of the wrong type during a medical procedure must be avoided, mixing different oils can also be disastrous. However, in the case of oil, the problem is more pronounced. Even nominally, similar oils such as two AW hydraulic fluids or two EP gear oils should not be mixed unless they can be independently confirmed as being chemically compatible.
One important, but often overlooked, role that our blood plays is the transportation of blood close to our skin surface to regulate temperature. The ability of blood vessels to expand or constrict to increase or decrease surface area allows our blood to serve as a source of warmth or as a cooling agent, depending on the ambient temperature. While oil lines don’t expand or contract, they do transport oil back to heat exchangers to eliminate unwanted heat or to the oil sump or reservoir where oil temperature can be controlled through increased residence time or the use of immersion heaters.
While less than 1% of the total volume of blood, white blood cells play an important role in helping to fight infections. Certain types of white blood cells directly fight bacteria, viruses, and other pathogens, while others produce antibodies to helps stave off infections. Monocytes have a unique role in being able to clean up dead cells. Most industrial oils contain less than 10% to 15% by volume of additives. Despite their relatively low concentrations, oil additives function just like white bloods cells in preventing “disease” including base-oil oxidation, protecting against boundary and mixed-film lubrication conditions, and controlling unwanted contaminants such as aeration and moisture.
Perhaps the closest parallel between blood and oil is the use of frequent sampling as a diagnostic tool. In the case of blood, blood samples are extracted by experienced medical personnel and submitted to a specialized lab for a suite of standard and non-standard tests. Once complete, the data is used by doctors, often in conjunction with other diagnostic tests, to infer a diagnosis and to provide prescriptive relief. In some cases where more severe issues arise, specialists use blood-sample data, along with their specialized knowledge, to predict more severe illness.
In the world of oil analysis, samples should be taken by a trained lubrication technician and submitted to a competent lab for analysis. Once analyzed, a trained analyst, such as a reliability engineer, can use the information to better understand asset conditions. This is often done in combination with other condition-based maintenance (CBM) tools, such as vibration analysis, ultrasound, thermography, or simple visual inspections. For more complex failures, additional testing, such as analytical ferrography, can be used by lubrication experts to further determine the root cause of machine failure.
Where pump or bearing failure is suspected, vibration analysis can be used to identify fault frequencies that can isolate the cause of the problem, just like a trained cardiologist can use an EKG to look for characteristic patterns to localize heart issues.
Good human health requires careful regulation of certain external “contaminants.” These include saturated fats, tobacco, and alcohol which, in excess, can all lead to diseases that can affect the cardiovascular system. It’s often said that diet and exercise are the key to a healthy lifestyle and while it’s all but impossible for any of us to live a “perfect” lifestyle, the better we eat, the more we work out, and the fewer contaminants we ingest, statistically the healthier we’ll be.
Machines are no different. For a machine, living a healthy life means keeping contaminants such as particles and moisture at low levels. For any machine, it’s highly unlikely that we can keep every single particle and every single drop of moisture out of the oil, but the cleaner and drier the oil, on average, the longer the oil and the machine will last.
One of the consequences of an unhealthy lifestyle is an increase in bad cholesterol, causing blockage of arteries, veins, and the heart. In any lubricant the same is true. Air, moisture, and certain solid contaminants can increase the production of varnish, a sticky resinous material that can plug valves, pumps, and other oil circulatory systems. The key to lowering varnish is to control operating temperatures, maintain healthy oil and, most of all, minimize contaminants.
Design for Reliability
What happens when we appear to do everything right and failures still occur? In the case of human health, it’s recognized that genetics play a role. A good example is the case of James Fixx who, despite being credited as the father of jogging as a recreational pursuit, completing several marathons every year, and writing endless books and articles on health and fitness, died at the age of 52. After his death, his physicians determined his demise was due to an earlier poor lifestyle as an adolescent, coupled with a genetic heart condition inherited from his father who died from a heart attack at age 43. In essence, Mr. Fixx inherited “faulty” genes.
With a machine, “design for reliability” plays a role in its health. Even the most rigorous maintenance program can’t overcome a poor design that is unable to cope with the loads, speeds, or operating conditions of the machine.
The next time you’re out in the plant looking at assets, think about how much the oil plays in maintaining machine health and how using many of the same health tips our doctors and medical professionals espouse can help your machines live a long, happy life. EP
Mark Barnes, CMRP, is Senior Vice President at Des-Case Corp., Goodlettsville, TN, (descase.com). He has 21 years of experience in lubrication management, oil analysis, and contamination control.