Abstract: An improved recovery fan cylinder for mechanical draft water cooling towers is provided which is configured with an upper reflex angle recovery section above the fan blade which gives unexpected increases in velocity head recovery as compared with conventional frustoconoidal stacks. The reflex stack hereof includes first and second superposed portions above the blade which are respectively oriented so that the external surfaces thereof cooperatively define a reflex angle; in preferred forms, the lower portion lies at an angle of from about 15.degree. to 30.degree. relative to the central upright stack axis, whereas the upper portion is oriented at an angle of 0.degree.-10.degree. on the same basis. Test evidence demonstrates that the stack of the invention permits unexpected reductions in fan horsepower, as compared with typical prior art stacks.

Abstract: Air moving mechanism is provided for equipment such as direct or indirect heat exchange cooling towers. Conventional cross-sectionally elliptical eased inlet structure leading to a fan opening or cylinder surrounding a rotary fan air mover is replaced by a much simpler, less costly, apertured airflow modifying baffle member which functions to define an invisible eased inlet for the fan. The specially shaped aperture in the baffle member is configured and arranged relative to the fan cylinder inlet to cause air removed from the tower casing and directed toward the fan to follow a transition path between the baffle member and fan opening or cylinder which generally conforms to and substantially fills the opening or cylinder inlet around the entire circumference thereof.