Sophisticated fluid designs, higher pressures, tighter clearances and electrohydraulics have made modern day machinery far more productive and user friendly, but they have also increased the need for cleaner fluid systems. Wear control specialist, Filter Focus has the solution.
Chief operating officer Craig FitzGerald points out that contaminants and particles as small as 2 to 5 microns can result in premature wear and efficiency loss. “Contamination directly impacts on the lifespan of an oil, as well as that of the component in which it is operating. The goal is to implement contamination control systems and practices that maximise machine and lubricant life, while minimising capital and operating expenses,” he says.
According to FitzGerald, all oil is contaminated to some extent when purchased. “The storage and handling practices will then determine the actual cleanliness of the oil before it is placed into operation. Particulate contamination measuring in the millions will be present in new oil even before starting, and during operation each contaminant has the ability to create up to four metal wear particles, thereby creating a cycle that grows exponentially. Standard OE filters are generally only capable of addressing solid contamination above 10 μm and are largely inefficient,” he continues.
“The successful removal of all solids, semi-solids, free water, dissolved water, depleted additives, varnish and sludge will result in reduced operating temperatures and less propensity to foam, oxidise or chemically alter. Preventing contamination from entering oils will drastically increase the operating life of lubricants too, as oil integrity is kept within specification for longer periods, leading to improved efficiency and machine availability.”
How to quantify oil cleanliness
The ISO 4406 standard establishes the relationship between particle counts and cleanliness. This internationally recognised model uses a code system to quantify contaminant levels by particle size in µm. Using ISO 4406, a machine owner or operator can set simple limits for excessive contamination levels based on quantifiable cleanliness measurements. This standard allows for the quantification of current particulate cleanliness levels and setting targets for cleanup.
The importance of keeping oil clean on a consistent basis
Contaminated oil destroys machines, and FitzGerald stresses that clean oil is one of the most important factors in extending the service life of the lubricated components of all machinery. “In hydraulic systems, clean fluid is essential for successful long-term operation. Although machines equipped with rolling element bearings are sensitive to particulate contamination, machines using fluid-film bearings are not immune to such damage. Even modest improvements in lubricant cleanliness can result in a significantly extended machine lifecycle.”
He highlights the fact that each machine class should be evaluated for cleanliness levels that are appropriate to its application. “Turbine electro-hydraulic control (EHC) systems and many aero derivative gas turbines are examples of industrial machines that require extremely clean oil for optimal performance and long life. Filter systems rated to remove particles as small as 3 to 5 μm are commonly used in such applications.”
FitzGerald states that studies on improving lubricant cleanliness in numerous industries have all shown dramatic extensions in expected machinery lifecycles. “In one example, a reduction of particles larger than 10 μm from 1000/ml to 100/ml resulted in a five-fold increase in machine life. An additional benefit of cleaner oil is that it is much easier to detect subtle changes in the amount of wear debris than in dirty oil.”
He reveals that studies undertaken by the Society of Automotive Engineers have shown engine wear reductions of 50% when filtering crankcase oil to 30 μm and up to 70% when filtering to 15 μm – compared to industry standard filtering to 40 μm. Filtration, storage and handling procedures are the key areas of focus in oil clean up. “It is important to measure and evaluate current cleanliness levels to establish baselines for comparison. From there, it is advisable to examine and evaluate current storage and handling practices, before setting cleanliness targets that are based on goals for longer machine life and reduced maintenance and downtime costs,” he concludes.
For more information contact Craig FitzGerald, Filter Focus, +27 (0)11 466 1268, [email protected], www.filterfocus.co.za
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