Fan assembly

A fan assembly comprising:

• (a) a metal outer chamber with a plurality of adjoining planar sidewall segments, wherein each planar sidewall segment forms an obtuse angle with the adjoining sidewall segments to form a tubular structure having a polygonal cross-sectional shape having at least five sides, the outer chamber defining a longitudinal axis extending between a first open end and an opposite second open end, wherein the outer chamber is formed by a first section part and a second section part mechanically fastened to the first section part, wherein each of the first and second section parts include at least two interior obtuse angles formed by the planar sidewall segments, wherein each of the first and second section parts includes a plurality of separate bent tab sections extending orthogonally from the planar sidewall segments in a direction away from the longitudinal axis to form a first end flange at the first open end and a second end flange at the second open end;
• (b) a first adapter ring attached to the first end flange, the first adapter ring defining a circular outer perimeter;
• (c) a second adapter ring attached to the second end flange, the second adapter ring defining a circular outer perimeter;
• and
• (d) a rotatable fan assembly disposed within the outer chamber, the rotatable fan assembly being configured to move an airflow stream through the outer chamber from the first open end to the second open end.