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Oil Cleanliness in Industrial Gearboxes

Oil Cleanliness in Industrial Gearboxes

I am looking for as much information as possible on oil cleanliness levels, oil analysis interpretation, etc... Applicable to industrial gearboxes and bearings.


RE: Oil Cleanliness in Industrial Gearboxes


I used to work for a company that did a lot of work with Falk out of Milwaukee, WI.  The Falk standard for the two most common configurations of their gearboxes is as follows:

unfiltered splash lubricated: ISO 23/20/18
filtered with 40 micron wire filters: ISO 20/18/16

You can get a lot of information from the Pall corporation.  They make industrial oil filters and are experts in oil contamination.  Very helpful people and I'm sure they have a website.


RE: Oil Cleanliness in Industrial Gearboxes


ISO 4406 provides guidance in charcaterizing the cleanliness of lube oils.  It is based upon counting the number of particles in given size ranges (>4 um, >6 um, >14 um) in a one ml sample.  This methodology has been adapted for use by some equipment manufacturers.

NAS 1648(National Aerospace Standard)provides similar guidance but uses a single characterization number to describe the particle size count and distribution in a 100 ml sample.



RE: Oil Cleanliness in Industrial Gearboxes

Are you still looking for information?? I wrote a paper on this subject for a large Mining Group and will e-mail you a copy of this if you like.

RE: Oil Cleanliness in Industrial Gearboxes


I would be interested in reading your paper.  Thank you.


RE: Oil Cleanliness in Industrial Gearboxes

can you send me the paper please?
You can mail it to

RE: Oil Cleanliness in Industrial Gearboxes

Hi icw please would you send it to me.
Best Robert

RE: Oil Cleanliness in Industrial Gearboxes

Read with interest your comments on FALK giving ISO codes on splash and filtered systems.
Why would one run a splash lubricated box four times dirtier than a filtered box?
I've seen 1500 HP FALK  boxes (bearings) fail in two years which is the result of running a box at ISO 23/20/18 and once the oil reaches this level of contamination, no bearing will last....... ask any bearing manufacturer.
I think gearbox manufacturers forget their boxes run on bearings - have no doubt they only consider the gears.
Agree with your comments about PALL Corporation - a good source of information on contamination control.

RE: Oil Cleanliness in Industrial Gearboxes

Hi icw,
please would you send to me the report you did.I had a major computer failure and the people who did the repair thought i had backed up so when they cleanded and installed a new hard drive i lost all.
many thanks

RE: Oil Cleanliness in Industrial Gearboxes

icw, If possible I would also like to recieve your paper on oil contamination
Thanks Bob

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