Fan assembly and method

Abstract

Fans according to some embodiments of the present invention include a spider, a central hub coupled to the spider, and two or more fan blades. One or more fan design features can be employed (alone or in combination) in the fans of the present invention, including the use of spider arms and/or fan blades having twisted shapes, spider lobes having cupped shapes, spiders and/or fan blades having thinner dimensions than conventional spider and fan blades in similarly-sized fans, fan blades having narrower widths, larger camber-to-chord ratios and/or tapering camber-to-chord ratios, and embossments located on the spider or the fan blades of the fan. In addition, pre-balanced spider assemblies can be employed as an alternative to balancing a fan after assembly.

1 . A fan, comprising:
 an axis about which the fan is rotatable;   a plurality of fan blades, each fan blade having a tip and a root;   a spider having a plurality of radially extending arms to which the plurality of fan blades are coupled, the tips of the plurality of fan blades defining a fan diameter greater than about 16 inches and less than about 24 inches; and   each spider arm having a cupped portion to which one of the plurality of fan blades is coupled, the cupped portions of the spider arms each having a curved cross-sectional shape defined at least partially by a radius of curvature that is less than 10 inches.   
   
   
       2 . The fan as claimed in  claim 1 , wherein each spider arm has a lobe at least partially defining the cupped portion to which one of the fan blades is coupled. 
   
   
       3 . The fan as claimed in  claim 1 , wherein each spider arm terminates in a lobe at least partially defining the cupped portion to which one of the fan blades is coupled. 
   
   
       4 . The fan as claimed in  claim 1 , wherein the radius of the curvature is less than 6 inches. 
   
   
       5 . The fan as claimed in  claim 1 , wherein the radius of curvature is between 3.5 and 4 inches. 
   
   
       6 . The fan as claimed in  claim 1 , wherein the spider has a steel body having a nominal thickness of no greater than about 0.080 inches. 
   
   
       7 . The fan as claimed in  claim 1 , wherein the spider has a steel body having a nominal thickness of no greater than about 0.065 inches. 
   
   
       8 . The fan as claimed in  claim 1 , wherein the spider has a steel body having a nominal thickness of no greater than about 0.055 inches. 
   
   
       9 . The fan as claimed in  claim 1 , wherein each spider arm has a length in a radial direction of the fan, each spider arm having a twisted shape along the length of the spider arm. 
   
   
       10 . The fan as claimed in  claim 1 , wherein:
 each fan blade has a length and a curved cross-sectional shape defining a camber-to-chord ratio at different radial distances from the axis; and   the camber-to-chord ratio of the fan blade is at least 0.075 along substantially the entire length of the fan blade.   
   
   
       11 . The fan as claimed in  claim 10 , wherein the camber-to-chord ratio is substantially constant along the length of the fan blade. 
   
   
       12 . The fan as claimed in  claim 1 , wherein:
 each fan blade has a length and a curved cross-sectional shape defining a camber-to-chord ratio at different radial distances from the axis;   each fan blade is coupled to a respective one of the arms at the root of the fan blade; and   the camber-to-chord ratio at the root of each fan blade is at least 0.09.   
   
   
       13 . The fan as claimed in  claim 12 , wherein the camber-to-chord ratio at the root of each blade is at least 0.12. 
   
   
       14 . The fan as claimed in  claim 12 , wherein the camber-to-chord ratio at the root of each blade is at least 0.16. 
   
   
       15 . The fan as claimed in  claim 1 , wherein:
 each fan blade has a length and a longitudinal axis along the length; and   the blade tip of each fan blade is disposed at an angle about the longitudinal axis with respect to the blade root.   
   
   
       16 . The fan as claimed in  claim 15 , wherein the angle is at least 6 degrees. 
   
   
       17 . The fan as claimed in  claim 15 , wherein the angle is at least 7 degrees. 
   
   
       18 . The fan as claimed in  claim 15 , wherein the angle is at least 8 degrees. 
   
   
       19 . The fan as claimed in  claim 1 , wherein the fan blades comprise aluminum and have a nominal thickness of no greater than 0.032 inches. 
   
   
       20 . The fan as claimed in  claim 1 , wherein the fan blades comprise aluminum and have a nominal thickness of no greater than 0.020 inches. 
   
   
       21 . The fan as claimed in  claim 1 , wherein the fan blades comprise steel and have a nominal thickness of no greater than 0.025 inches. 
   
   
       22 . The fan as claimed in  claim 1 , wherein the fan blades comprise steel and have a nominal thickness of no greater than 0.015 inches. 
   
   
       23 . The fan as claimed in  claim 1 , wherein:
 the fan blades each have a length and a width; and   the width of each fan blade is no greater than 8 inches.   
   
   
       24 . The fan as claimed in  claim 23 , wherein the width of each fan blade is no greater than 7 inches. 
   
   
       25 . The fan as claimed in  claim 23 , wherein the width of each fan blade is no greater than 6 inches. 
   
   
       26 . The fan as claimed in  claim 1 , wherein the spider has at least one embossment oriented to provide resistance to bending of the spider. 
   
   
       27 . The fan as claimed in  claim 26 , wherein the embossment is on a peripheral edge of the spider. 
   
   
       28 . The fan as claimed in  claim 1 , wherein the fan blades each have at least one embossment located at the root of each fan blade.