| Hydraulic Size |
| Calculation |
| The hydraulic size of a filter
media is the size it would have if it was all of one uniform size. This material would then have the same hydraulic loss as the sample. It is the averaged area and is used in the Carman and Kozeny equation to determine the hydraulic gradient through the filter bed. |
[Results taken from the example on the specification page]
| Sieve mm | Retained % | Retained/Sieve |
| 2.50 | 2.80 | 1.12 |
| 2.00 | 25.40 | 12.70 |
| 1.60 | 38.10 | 23.80 |
| 1.40 | 18.60 | 13.30 |
| 1.18 | 11.90 | 10.10 |
| 1.00 | 3.20 | 3.20 |
| Totals | 100.00 | 64.20 |
| 1 | Divide the percentage retained on each sieve by the sieve size | |
| 2 | Total the calculated figures | 64.20 |
| 3 | Divide the result by 100 | 0.642 |
| 4 | Take the reciprocal | 1.55 |
| 5 | Add 10% | 1.71 |
| The hydraulic size of the sample is 1.71mm | ||