I currently have a dryer that is vented to an interior wall. The vent makes a 90 degree turn up to the attic, 90 degree turn to run over the garage rafters, 90 degree turn to run down the exterior wall exiting the house. I have to clean the vent hose with a leaf blower annually to insure proper flow. Does anyone know of a in-line booster fan similar to an A/C duct fan, obviously smaller? Any other advice would be great as well.

With 3 bends you're probably only really supposed to have a 10' duct run and it sounds like yours is a lot longer. Yes, they do make an in-line booster. Google "dryer duct booster" and you'll get quite a few hits. Fantech is one manufacturer. They include a lint filter.

Thanks for keeping the vent clean. I've seen a lot of dryer fires.

Emt/volunteer firefighter/arff firefighter