VARNISH POTENTIAL RATING ( VPR) TEST SERVICE - Membrane Patch Colorimetry ( MPC)

Varnish accumulation was the result of one or a combination of factors such as thermal degradation, oxidation, microdieseling ( adiabatic compression) , additive depletion and contamination. It prohibits the proper movement of mechanical parts and could ultimately cause a turbine to trip or shut down. Varnish The Varnish Potential Rating ( QSASM) - A sample of oil is mixed with solvent and pulled through a filter-membrane. The color spectra of the insolubles collected can be correlated to the amount of insolubles in the oil and the " soft contaminants" present. The high level of soft contaminants in the sample indicates that the oil has a high propensity to produce varnish. It has also been observed that a process of Auto-Degradation can be occurring in the oil. Electrostatic Spark Discharge ( ESD) , Flow Electrification Electrostatic Spark Discharge ( ESD) is a lubricant degradation mechanism that has been found to occur in fluid systems when oil passes through small passages such as filters, hydraulic valves and bearings. There are several factors that increase the risk of ESD, including: • Lower temperature • Higher Viscosity • Higher Oil Density • Higher Oil Conductivity • Higher Flow Rates • Higher Reynolds Number • Higher Entrained Air • Lower Levels of Insolubles ( dirt) • Lower Levels of Moisture ( < 100ppm water) • Smaller Filter Pore Size • Poor Filter Design Membrane Patch Colorimetry ( MPC) : This is an excellent tool in determining the varnish potential of an oil. This is a laboratory method of extracting insoluble contaminants from a used oil sample, followed by spectral analysis of the separated material. The process of making a patch isolates and agglomerates insoluble by-products associated with varnish. The color of the membrane patch provides a guideline as to the extent of varnish potential. With MPC, a direct correlation is made between the color and intensity of the insoluble contaminants and oil degradation. The test is designed to identify soft contaminants directly associated with oil degradation. This test is considered to be highly sensitive and reliable for detecting subtle changes in insoluble levels.