GEK Wiki / Gas Cowling and Rotary Grate
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Gas Cowling and Rotary Grate

Page history last edited by jim mason 15 years, 2 months ago

back to Fabrication Instructions home

 

Building the Gas Cowling and Rotary Grate for GEK v2.0

 

 

 

Parts needed:

     - Gas cowling vessel tube

     - Bottom end plate

     - Top flange ring

     - Gas outlet square tube to cyclone inlet

     - 1/2" close nipple

     - Grate rotation bushing for bottom

     - Cover plate for ash clean out port

     - 5/16 x 5/8 bolts (4 count)

     - 5/16 wing nuts (4 count)

     - 1/2 pipe lenghts for leg attach points

     - legs (4 count)

 

1.  Weld (4) 5/16" bolts into ash port holes in bottom end plate.

  • Bolts should extend downwards towards slag side
  • Completely weld bolt head to bottom so that it is gas tight
  • Temp install ash port plate with wingnuts. You will need to add gasket material later. Clean up holes in ash port with 11/32" drill if necessary

 

 

 

2. Tack bottom end plate into vessel tube 

  • Part Orientation: Slag side of end plate is down.  Ash clean out port is to the left when looking from the front.  Vessel tube seam is in back.  1/2" hole is in front.
  • Tab and Slot start position: The "center" of the slot at the vessel seam is 3/16" from the material edge.  This results in a 1/4" space between the edge of the tab and slot on the material side of the slot.
  • Clamp bottom end plate into vessel cylinder or press together in sections and tack. Progress around the bottom seam in one direction, making sure the vessel tube is tight onto the end plate.

 

 

 

 

3. Tack top flange ring onto vessel tube.

  • No special orientation.  Use any tab and slot position.  Slag side should be down.  Flange ring should be flush with top of vessel tube.
  • Clamp top flange ring into top of vessel tube and tack into place.  ONLY tack/weld on the bottom side of the flange.  If you have enough clamps, do the entire ring.  If you do not have enough clamps, work in one direction, making sure the vessel is tight out to the flange.

 

 

 

4. Tack side seam

  • Tack down side seam of vessel.  You may need to squeeze the vessel to get the seam parallel, making sure overlap stays consistent.  You can use a tiedown strap, rope, or just push it down onto the table to get the seam together and parallel.

 

 

5. Assemble gas outlet and tack onto vessel tube

  • Weld flange into end of 2" square tube.  Flange is symmetrical so no special orientation.  But make sure the tube is flush with the flange plate
  • Weld half of a 1/2" coupling over the hole in the side of the square tube.  This is to create a measurement bung.  Make sure the weld is fully sealed.
  • Tack square tube assembly onto gas cowling.  Make sure the flange is well aligned with the gas cowling.  Misalignment will cause the cyclone to be cocked when fully assembled.
  • Clean up flange holes with a 11/32" drill 

 

   

 

6. Fully weld all tacked joints

  • Stitch weld in short sections to prevent warpage.  But make sure to fully seal all joints
  • Weld ONLY on the underside of the flange ring.  No welding on the top joint side of the flange
  • Be careful to not warp the top flange when welding the gas outlet into place
  • Grind top surface of flange flat after welding
  • Clean up flange holes with a 11/32" drill

 

7. Weld on center rotation tube on outside bottom and add 1/2" close nipple

  • Put 1.5" x 6" pipe nipple in rotation bushing to help center the bushing in bottom of gas cowling.  Remember that this is a rotation point, so alignment is important.  Make sure rotation bushing stays firm on bottom while tacking and that the pipe nipple is not binding on the side of the hole.
  • Tack 1/2" close nipple into small hole in side of cowling protruding outward. Make sure it aims out at 90 degrees. Fully weld around it, and screw on a 1/2" cap to protect the threads

 

 8. Weld on leg attach stubs

  • 4 legs at 90 degrees separation around vessel.  This is 45 degree off the front axis, like the legs of a chair.
  • Overlap leg stubs 2" up side of gas cowling.  3" of stub extends below cowling.
  • Use one leg as an extension jig to make sure leg is aligned while welding.
  • Drill a 11/32" hole in each 1" x 10" tubing leg, about 1" down from one end
  • Weld a  5/16" nut over each 11/32" hole
  • Insert legs onto stubs.  Use 5/16" bolts to bind them in place.

 

   

 

 

 

 

Rotary Grate

 

 

Parts needed:    

     - Round perforated grate

     - Grate stabilizer square tubes: 1/2" x 1/2" x 5" (5 count)

     - 1.5" x 6" pipe nipple

     - 2" x 1.625"L pipe spacer

     - 1.5" coupler

     - 1.5" plug

     - 1.5" cap

     - Grate turning bar 

 

 

1.  Make grate center attachment.

  • Weld 1.5" pipe coupling into center of grate over precut center hole.  Careful centering is important so the edge of the grate doesn't scrape against the gas cowling wall while agitating char.
  • Weld spacer onto coupling.  The spacer is a 2" x 1.625" pipe section.  When grate is installed, this spacer rides on the bottom of the gas cowling, which locates the grate to the proper height (1.5") below the reactor.
  • Weld one end of one 1/2" x 1/2" x 5" square tube piece to the spacer, extending it out parallel to the grate to create an agitation arm. The tube should be about 2 3/4" above the grate along its length.

 

2. Weld support bars on bottom of grate

  • Support bars are the 1/2" x 1/2" x 5" square tubes.
  • Weld tubes from from center coupler out axially along the grate bottom.  Make sure to clamp down the grate while welding to prevent warpage.  A few stitch welds are fine.  No need for a full length weld.

 

     

 

2. Install grate and confirm dimensions

  • Test 1.5" x 6" nipple to make sure it turns easily in bushing at bottom of gas cowling.  Clean and/or sand if needed.
  • When fit is confirmed, screw 1.5" x 6" nipple into the bottom of the grate.  Put 1.5" plug in center of top of grate.  Lower grate down into the gas cowling. 
  • Confirm that grate turns inside the gas cowling without binding on the walls
  • Confirm that top of grate is 17.5" below top of gas cowling flange ring.  Measure this distance from the flange surface (use a straight bar across the opening) to the center of the grate.  The edges might bend down a bit so measuring to the edges is not good.  The reactor inserts 16" down into the gas cowling, leaving 1.5" to the grate.
  • Weld grate turn handle on 1.5" cap and install on end of grate post undernearth the gas cowling.

 

 

 

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