Fan and shroud assembly

An axial flow pusher fan assembly having a fan with a plurality of fan blades surrounded by a non-rotating annular shroud, each fan blade having an upstream edge defining an upstream plane and a downstream edge defining a downstream plane, and the fan having a diameter, wherein the shroud comprises:

• an annular first wall which extends radially outwardly, the first wall being positioned between the upstream plane and the downstream plane;
• an annular second wall which extends downstream axially and radially outwardly from an upstream end, the second wall being downstream with respect to the first wall in an air flow direction, and the second wall having a flexible seal joint, the first wall having a height in the radial direction which is greater than 0.05 times the diameter of the fan;
• and
• an annular third wall which extends between the first wall and the second wall, the third wall having a curved cross sectional shape, the third wall having an upstream end which is connected directly to and forms a smooth transition with the first wall, and the third wall having a downstream end which is connected directly to and forms a smooth transition with the second wall, the third wall having a radius of curvature which is preferably less than 0.05 times the fan diameter.