Heat exchange apparatus including a toroidal-type radiator

A heat exchange apparatus comprising:

• a heat exchanger means including a toroidal radiator structure, said toroidal radiator structure including a toroidal radiator core having a plurality of radially extending cooling air passageways formed therethrough, said toroidal radiator structure further including a first radially extending wall and a second radially extending wall axially spaced and substantially parallel with respect to said first wall, said first and second walls substantially defining the axial limits of said toroidal radiator core and an air-receiving plenum chamber disposed radially inwardly of said toroidal radiator core;
• a rotatable, axial flow fan having a plurality of circumferentially spaced, radially extending impeller blades;
• and
• a generally annular fan shroud means supported within an opening formed through said first wall and encircling the fan, said fan shroud means including a generally cylindrical, axially extending throat section, an annular, generally radially extending flat flange section, said flat flange section being spaced radially outwardly and axially in a direction downstream from said throat section and having a radial length substantially equal to the axial length of said cylindrical throat section, said fan shroud means being positioned with respect to said toroidal radiator structure whereby said flat flange section lies substantially in a plane spaced and parallel with respect to said first and second walls, and an annular intermediate section extending between and operatively interconnecting said throat section and said radial flat flange section, said throat section, intermediate section, and radial flat flange section being effective to produce a low pressure region between the air stream flowing over the surface thereof and such surface when the fan is in operation.