Patent ID: 7381129

Claim:
An air moving device comprising: a housing having an air inlet at a first end and an air outlet at a second end spaced from said first end with an air flow passage between said first and second ends, a rotary fan mounted in said housing near said air inlet and having an impeller with a diameter and a plurality of blades that produce an air flow with rotary and axial air flow components, said blades each having an upstream edge and a spaced downstream edge, and a plurality of spaced, radially extending air guide vanes that extend longitudinally in said housing between said impeller and said air outlet for converting said rotary component of said airflow into laminar and axial air flow in said housing, said vanes each having an upstream end, said vanes being spaced from said impeller by a gap between said upstream ends of said vanes and said downstream edges of said blades, said gap having a selected size, said gap size being selected to be less than one half of said diameter of said impeller to avoid generation of turbulence and reduce static back pressure in said air flow, whereby said air flow exits said air outlet in an axial stream extending beyond said air outlet in a columnar pattern with minimal lateral dispersion.