Varnish Potential Testing
Varnish is a soft contaminant, a high molecular weight substance that is insoluble in oils, sticky, and inclined to deposit on metal surfaces. Varnish material in lubricants falls out of suspension and coats working surfaces, where it hardens and prohibits the proper movement of mechanical parts. Where varnish accumulates, valves and other moving parts stick, resulting in the turbine tripping or shutting down. Because varnish deposits are adhesive, they attract solid contaminants, such as dirt and metal debris, which creates abrasive wear.
Varnish is the result of one or a combination of:
- Thermal degradation
- Oxidation
- Microdieseling (Adiabatic Compression)
- Additive depletion
- Contamination
While there is no direct measurement of varnish buildup, ALS Tribology offers a comprehensive test package that can predict a lubricant’s potential to cause varnish accumulation. We offer the most extensive varnish potential testing in the industry. Our seven-step, multiple parameter approach is appropriate for turbines, compressors, and hydraulic systems; testing includes:
- Blotter Test
- Color
- Ultracentrifuge Sediment Rating
- Pentane Insolubles
- Membrane Patch Colorimetry
- Particle Count
- % RULER® (% Phenolic & Amines)—our most recent addition*
*Technically referred to as Linear Sweep Voltammetry, RULER® measures hindered phenolic and aromatic amine antioxidant content, the primary antioxidants used in industrial oil and zinc-free turbine oil applications. By measuring the depletion and available reactivity of these antioxidant compounds in addition to routine performance tests, you can effectively monitor the service life of used lubricants. The addition of the RULER® to the ALS industrial and power generation lubricant test package produces additional and valuable oil oxidation information to help you optimize lubricant performance life and equipment reliability.
Visit the download section of our site to learn more about this service as well as the many other testing and analyais services offered by ALS Tribology.
