Patent ID: 8579582

Claim:
A drying fan for drying a surface comprising a housing, a motor driven fan supported on said housing for rotation about an axis and having fan blades directing air radially relative to said axis, said air having a velocity V 0 immediately adjacent said blades, a velocity V 1 radially outwardly of said blades at a first circumference therearound, and a velocity V 2 further radially outwardly of said blades at a second circumference around said first circumference, said housing comprising a shroud extending radially outwardly of said blades and axially spaced from said surface by an annular gap therebetween defining an annulus providing an air flow channel, wherein said shroud has a shape selected to minimize differential velocity between V 0 and V 1 and V 2 , wherein said shroud has a taper selected to provide a narrowing venturi to maintain substantially constant air flow velocity from said first circumference to said second circumference notwithstanding the larger fanned-out dimension of the latter.