WHY BE CONCERNED ABOUT VARNISH?
Lubricant varnish has become a significant maintenance problem in many critical hydraulic and lubrication oil applications, such as gas turbines, compressors, and hydraulic presses. Turbine oil varnish has been a particularly high profile issue over the last decade. A very small amount of varnish that settles in a susceptible zone, such as a fuel control or IGV valve, can prevent the system from starting properly, resulting in a fail-to-start condition or in some cases a unit trip.
WHAT CAN VARNISH DO TO MY SYSTEM?
Decrease the effectiveness of heat exchangers, making it more difficult to control fluid temperature.
Increase the wear rates of valve components, load gears, and in some cases, bearing surfaces.
Shorten the lubricant’s life by reacting with the anti-oxidant system
Cause premature filter change-outs and oil flow restrictions
Impairs visibility through level and sight flow indicators
When varnish contamination is severe and causing operational issues (stuck servo-valves, high bearing temperatures, etc.) a “Varnish Flush” is often the only way to bring a hydraulic or lube oil system back to “like new” cleanliness conditions.
Oil Filtration Systems (OFS) has both the equipment and the experience needed to quickly remove varnish that has plated out on the metal surfaces within a hydraulic or lube oil system.
An appropriate “system cleaner” is typically mixed with the oil to act as a solvent to break up solid deposits that have accumulated in the piping and reservoir, and after recirculation within the system for a period of time, the contaminated oil/solvent mixture is eventually drained out of the system and disposed of. Depending on several factors, a “scavenging” oil is sometimes used to rinse the system, and a new fill of filtered oil is then pumped into the system.
After a “Varnish Flush” has been performed, OFS can then provide a Varnish Removal System that continually recirculates the oil and prevents varnish from accumulating in the system over time.
OFS will work with your team to develop a custom Flush Plan that best suits your application, time-line, and budget.
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