| Method | Automated Laser Particle Counter |
| Standards | ISO 4406 |
A technique, primarily used for hydraulic oil samples, to determine the degree of particulate contamination present in a given oil sample across three specific particle size bandings.
A portion of sample is passed through a flow cell through which laser-light is passed en-route to a CCD sensor.
The number of “shadows” and their size determines the count of particles in the sample.
A “code” is assigned to particle count values derived at three different micron levels: greater than 4 microns, greater than 6 microns and greater than 14 microns.
A code is generated, consisting of three numbers, e.g. 17/15/12. This would indicate that:
| Particle Size | Code | Particles / mL |
|---|---|---|
| More than 4 micron | 17 | 640-1300 |
| More than 6 micron | 15 | 160-320 |
| More than 14 micron | 12 | 20-40 |
This is of particular importance for hydraulic systems where small particulates can have catastrophic effects.
The technique is also a good indicator of the cleanliness of new lubricants, or the need to filter a new oil prior to use. Trending can also monitor ingress of fine particulates over time (e.g. fine wear and dust).
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