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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 micrometers (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.
Keeping oil clean on a consistent basis
There is no getting away from the fact that contaminated oil destroys machines, and Craig
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 maintains that eachmachine class should be evaluated for cleanliness levels that are appropriate
to its application.What industry has previously accepted as normal, needs to seriously be addressed,
if improvements to efficiencies and performance are to be gained.
Although the precise improvements in machine life as a result of cleaner oil are specific
to each individual machine and application, Craig says that studies on improving lubricant
cleanliness in numerous industries have shown dramatic extensions in expected machinery
lifecycles. “In one example, a reduction of particles larger than 10µm 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.”
What’s more, he says, studies undertaken by the Society of Automotive Engineers (SAE) have
shown engine wear reductions of 50% when filtering crankcase oil to 30µm, and up to 70%
when filtering to 15µm - when compared to the industry standard of filtering to 40µm.
Bearing this in mind, Craig stresses that 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.
Filter Focus Chief
Operating Officer Craig
FitzGerald points out
that contaminants and
particles as small as two
to five micron can result
in premature wear and
efficiency loss.
Above left
: Graph illustrating lubrication
quality and its impact on equipment life
and maintenance.
Filter Focus are successfully established as
global leaders in Reliability engineering and
Wear control; offering industry substantial
and quantifiable performance improvements
to plant and equipment. By combining
expertise in the fields of filtration, lubrication
and tribology; Filter Focus yields considerable
financial benefit to its customers, while
diligently conserving the environment.
