Varnish Potential Testing

Method Membrane Patch Colourimetry by Spectrocolourimeter
Standards ASTM D 7843

What is it used for?

Varnish is typically formed by the degradation of in service lubricating oils, and is the scourge of hydraulic systems and turbines.


How does it work?

A portion of the oil sample is passed through a filter patch, which isolates and agglomerates insoluble breakdown products associated with varnish. The extent of varnish potential is determined by the colour of the patch generated; put simply, an excessive amount of yellows and blacks implies a greater degree of varnish potential.


What do the results tell us?

The likelihood/timescale of the current lubricant beginning to deposit varnish in a lubricated system.


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