Shoebox compressor question

OK guys I've watched a scuba compressor fill my airpacks and watched just how much water is released before the seive filter during pressure building it's actually quite a bit.I'm wondering does the shoebox have a manual bleed before going into a seive filter like Joe B's ? I'm thinking that with out a manual or auto bleed system you would run through filters fairly fast or not get all the moisture out.
Thanks guys/gals :)