Our old chip conveyor had the same filter problem every three weeks like clockwork. We switched to a different brand of disposable filters that were a bit more porous, and that gave us an extra ten days between changes. Still took forever to sort out the mucky coolant in the sump though.
Ugh, tell me about it. I mean, dealing with that nasty sludge is just the worst part of the whole job. Maybe it's just me but it always takes way longer than you think it will.