Lubricant Contamination Machinery's Handbook, 31st Edition
2518
14
Points shown at 4.6 and 14 microns represent ISO cleanleaness Code 4406 (1999 sampling rates)
12
10
8
6
4
2
0
4 6 10 14 20
30
40 50
Contamination Size in Microns
Fig. 13. Macpherson Contamination Effect Curve The graph in Fig. 13 clearly shows the relationship between bearing life extension and contaminant size. By focusing on controlling contaminates less than 10 microns in size with quality filtration methods, expected bearing life is more than tripled. ISO Cleanliness Code.— When performing a solids lubricant analysis and cleanliness testing, the ISO Cleanliness Code ISO4406 (1999) is used as a guide. The number of 4-mi- cron, 6-micron, and 14-micron diameter particles in a 1-ml lubricant sample are counted and compared to a particle concentration range (see Table 19), then assigned a cleanliness code number for each particle count size. Table 19. ISO Cleanliness Code 4406 (1999) Particles per ml Particles per ml More Than More Than
Up to and Including 160,000 80,000 40,000
Range Number (R)
Up to and Including
Range Number (R)
80,000 40,000 20,000 10,000 5,000 2,500 1,300 640
24 23 22 21 20 19 18 17 16 15 14 13
20 10
40 20 10
12 11 10
5
20,000 10,000 5,000 2,600 1,280 640 320 160
2.5 1.3 0.64 0.32 0.16 0.08 0.04 0.02
5
9 8 7 6 5 4 3 2
2.6 1,28 0.64 0.32 0.16 0.08 0.04 0.02
320 160 80 40
80 1 Example: An ISO code of 21/19/17 would represent findings of between 10,000 to 20,000 4-micron sized particles per ml, between 2,500 and 5,000 6-micron sized particles per ml, and between 640 and 1,280 14-micron sized particles per ml; this sample would be considered very dirty. 0.01 Typical cleanliness targets for rolling element bearings would start at 16/14/12 or better, 17/15/12 or better for journal style bearings, 17/14/12 or better for industrial gearboxes, and 15/12 or better for hydraulic fluids.
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