Membrane Filtration is used as an analysis technique to collect, identify and measure particles in lubricating oils.
This test method involves passing a representative oil sample through a Millipore membrane filter. All particles larger than the filter mesh size will be retained on its surface, which will be analyzed later. There are two simple procedures for analyzing particulate contamination:
- Particle Counting – is a quantitative method that uses the microscope to count particles to determine levels of contamination (SAE – ARP 598B);
- Gravimetric - is a quantitative method that determines the levels of contamination by weighing.