FAN FOR COOLING TOWER Russian patent published in 2003 - IPC

FIELD: industry heat-and-power engineering equipment. SUBSTANCE: fan comprises shaft with hub, blades with spars and ribs and case. Fan is formed as multilevel device. Hub of each level is made as box with square section in fan rotation plane. Box side walls are the extensions of outermost spans of blades located opposite to each other. In multi-spar blade embodiment box has several compartments. Number of box compartments is equal to number of connected spars. Box compartments are equipped with additional inner walls located in parallel to box side walls and formed as extensions of subtending inner spars of blades located opposite to each other. In demountable fan embodiment spars are connected with hub walls in wall rib areas by detachable connection means, for example by joining bars, particularly by angle bars. Hub box side walls are formed with installation orifices for blade angle of attack changing. Hub box is reinforced by additional wall, which is an extension to spar with selected angle of attack. Replaceable hubs may be used to change angle of attack. Hub box bottoms have pattern of orifices to adjust different relative angles of turn for each level hub. Each level consists of two blades located opposite to each other. EFFECT: increased strength properties and stiffness, enhanced aerodynamic properties, improved operational efficiency and decreased fan mass. 7 dwg