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Centrifugal Fan

Page history last edited by jim mason 11 years, 6 months ago

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See here for the CAD files of the sheetmetal parts



Building the Fan for GEK v2.0


Parts needed:


     -circular fan plate with 5 blade slots

     -5 fan blades

     -shaft collar


     Fan Housing:

     -top fan housing plate

     -bottom fan housing plate

     -fan housing side strip

     -threaded inlet nipple

     -5/16" x 5/8" bolts (8count)

     -5/16" threaded rod


1. Assemble the fan


  • Drill out the shaft hole in the center of the plate with a 5/16" bit. Insert a 5/16" bolt through the shaft collar and then through the plate, adding a nut to tighten on the other side of the plate. Be certain to place the collar such that the head of the set screw is oriented midway between the blade slots. This will guarantee access to the screw once the blades are welded on. Weld the shaft collar to the plate, all the way around except where it will interfere with the set screw. Remove the bolt and nut.
  • Fit a blade into the slot, using the tab on the blade. Fit the blade such that the outer edge is flush with the edge of the plate. Make 3 small welds along the blade tab on the bottom of the plate to secure it. Ensure that the blades stand exactly 90 degrees to the plate. Repeat until done. 3 small welds for each blade on the bottom of the plate is sufficient. Make sure your welds are evenly spaced, this will ensure the fan stays balanced in operation. Grind the weld bumps down evenly.





2. Assemble the fan housing


  • Insert 4 bolts into holes in the fan housing bottom plate. Start with the orientation shown in the photo. It is very easy to mistake the orientations of these parts and cause yourself aggravation so refer very carefully to the photos. Using nuts to hold the bolts in place, make small welds to the bolt heads to secure them.
  • Start fitting the fan housing side strip to the bottom plate as shown. Tabs in the strip fit into slots in the plate. Fit the strip tightly to the plate, and tack weld as you go along counterclockwise. It will be helpful as you go to flip the housing over and weld the slot/tab joints on the back.
  • Insert 4 bolts into the fan housing top plate, and secure with nuts and welds as decribed above. Again, pay very close attention to the orientation in the photo. Flip the plate over and fit to the rest of the housing, inserting the side strip tabs into slots in the top plate. Fit up tightly and tack as you go, then weld the tab/slot joints. Fit the 2" close nipple over the outlet hole and tack in place. Stitch weld the entire housing together to make it airtight. Weld all the way around the nipple.
  • In the 2 vacant bolt holes insert the included length of 5/16" allthread. Weld it in place with thread protruding up and down from either hole approximate to the protruding lengths of the other bolts previously welded.








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