Vol. 16 #2, Dec. 1989 - Screen packs 1
When using fine screens in a pack, use a coarser screen as the first upstream screen to catch large dirt particles, to add a little life to the fine screen.
To help prevent blowout, remember to back up fine screens using progressively coarser ones downstream.
See also
Assembling screen packs
Screen packs 2
Screen utilization