HYDRAULIC FLUID ANALYSIS TESTS

Particle Count ISO 4406 - 1999 - 3 codes

The sample is pumped through a sensor, using a syringe attached to a Screw Thread Device (STD) which counts and sizes the particles. One ml of sample is counted repetively until stable results are achieved. The results are assessed against NAS 1638 or ISO 4406 to give ratings which determine the cleanliness of the fluid.

Hydraulic systems are sensitive to the presence of solid particulate matter or 'dirt'. Dirt particles interact with moving surfaces that accelerate wear. If they are not removed or at least diluted, loss of operating efficiency and eventual breakdown is more likely. Sizing and counting of particulate contamination is  measured by using a laser light obscuration method. Counts are recorded as particles per 1 ml in various size ranges depending on requirements (NAS or ISO codes). Limits are set by the manufacturers.

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