I have seen those same "in line" duct blowers used in exhaust ducts for cinema projector lamphouses-both on film and digital projectors-Some cinema suppliers sell those blowers.See thhis on the "Film Tech" website.Grainger sells these,too.So-they are good for things besides dryers-oh yes see those in air ducts for radium venting systems.
One of our members, Fred, in Illinois has one of these for his basement dryer, a gas Neptune. It works quite well for the long run to the outside wall.