Page 266 - Parker - Hydraulic and Lube Filtration Products

Appendix

Micrometer Conversions

US and ASTM Std Actual Opening (µm)
Sieve Number (in)
10 0.0787 2000 Relative Size of Particles
Magnifi cation 500x
12 0.0661 1680
14 0.0555 1410
149µm
16 0.0469 1190
18 0.0394 1000
25µm
20 0.0331 840
25 0.0280 710
30 0.0232 590
35 0.0197 500
40 0.0165 420 10µm
74µm
45 0.0138 350
50 0.0117 297
2µm
60 0.0098 250
40µm
70 0.0083 210
80 0.0070 177
100 0.0059 149
120 0.0049 125
140 0.0041 105
170 0.0035 88
Linear Equivalents
200 0.0029 74
1in = 25.4 mm = 25,400 µm
230 0.0024 62 1mm = 0.0394 in = 1,000 µm
270 0.0021 53 1µm = 1/25,400 in = 0.001 mm

-5
1µm = 3.94 x 10 in = 0.000039 in
325 0.0017 44
400 0.00142 36
550 0.00099 25
Formulas
625 0.00079 20 Velocity (ft per sec) = 0.4085 x gpm
2
d (ID in)
1,250 0.000394 10
1,750 0.000315 8
Conversion Rates
2,500 0.00097 5
1 cu ft = 7.48 gal
5,000 0.000099 2.5 1 gal = 231 cu in
2 cu ft water = 62.42 lb
12,000 0.0000394 1
1 gal water = 8.34 lb
1 US gal = 0.833 lmp gal
Micrometer Comparisons
1 lb/in 2 = 2.31 ft of water = 2.036 in Hg
Substance (µm) °F = 9/5°C+32
Table Salt 100
Metric Conversion Formulas
Human Hair (average dia) 50-70 mm = inches x 25.4
White Blood Cell 25 m = feet x 0.3048
cm 3 = cu in x 16.39
Talcum Powder 10 m 3 = cu ft x 0.028
Cocoa 8-10 kg = pounds x 0.454
kPa = psi x 6.895
Red Blood Cell 8 lpm = gpm x 3.785
Bacteria (cocci) 2 °C = 5/9 (°F-32)
Note: Lower limit of visibility (naked eye)—40µm

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