www.spiraxsarco.com/products.../strainers-and-filters.asp These are industrial strainers and if properly sized (GPM vs. psid) will affect good protection and low flow resistance ... make your selection based on the 'flow vs. ∆P' curves, just like you do when selecting filters.

To keep the system ∆P low avoid, 'sharp elbows', pipe transitions, etc. ... use long radiused els if elbows are needed, etc. and 'oversize' if needed.