I would like to ask if anybody has an experience with laser particle counters used for analysis of fully synthetic diesel engine oils (i.e. 0W30)? We want to find and use a laser particle counter for such oil contamination monitoring. The target is an identification of acceptable contamination limits. Our concern is that such oils can be simply 'too black' for laser analysis and additives could distort the measurement...
Do you have any experience? Thank you in advance.

We use pore blockage particle counting on engine oils, this way we avoid diluting the sample to run through our laser particle counter.

Libor

Please let me know your e mail,I will send some information

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The Promlem with engine oil laser particle counting is twofold.
1/engine oils are dark, especially after use
2/ large particles will block the sensor and cause problems.
We have done this work in the past but found the results to be unsatisfactory(very high count), high dilution factorr required and sensor blocking
Other methods ie pore blocking only give an ISO code estimate.
Not tried patch test with auto counting which may be the answer.

Both Laser particle counters (>4 um) and older style light bulb particle counters all operate on the light blockage method. Neat in service crankcase oils are too dark to permit crisp definition of particle sizes of interest. There are three solutions. The first is to determine the % soot by some means. if the soot is <<0.1% then you can try dilution with a compatible solvent (ask your lubricant supplier.) Ihis may not work. If this does not work, one alternate is ASTM F312 Standard Test Methods for Microscopical Sizing and Counting Particles from Aerospace Fluids on Membrane Filters. This is very accurate but will require a qualified lab. The last, and unfortunately the preferred method is the pore blockabe method. This method will ignore the soot and count only the hard particles. Unfortunately there is no calibration standard for this method that I know of. Good luck

The LNF does indeed do a particle count on Sooted oils, however dilution is needed and results may vary.

To further compound your problem, synthetic oils often appear to confuse the LNF giving extremely high counts (on both gearbox and engine oils) - would like to know if anyone else experiences this problem and why?

If you are using a pore blcokage type, make sure you install the special o-rings for synthetic oils, the pressure transducer seals may swell up and jam.....

Andy

amigo Andrew los valores de niveles de limpieza ISO (1999 ) 4/6/14 um se distorcionan mucho y sobre todo el mas afectado es el conteo de particulas sliding, cuando la muestra de aceite de motor presenta fibras en exeso ,el laboratorio dode laboro ha realizado una investigacion para saber las larmas que nos permiten saber que numero de fibras no afecta el iso ni la repetibilidad del analisis,cuando repetir el analis pues hay casos cuando la cantidad de fibras es moderado en un segundo analisis no se detectan fibras.
Pero en el caso de altas concentraciones de fibras un analisis exacto y presiso es imposible.
Por favor comuniquese con migo para darle mayores detalles .nehemiasweb@hotmail.com