GEK Wiki / v3_5 Gas Cowling and Rotary Grate
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v3_5 Gas Cowling and Rotary Grate

Page history last edited by jay 14 years ago

Back to Fabrication Instructions v3.5

 

1) Building the Gas Cowling and Rotary Ash Grate for GEK v3.5

 

    

I. Parts List:

Gas Cowling:

     - Gas cowling vessel tube

     - Bottom end ring- 14 3/4" diameter X 1 1/2" width

     - Bottom end plate- (not pictured)

     - Bottom end plate tube (for ash grate handle)

     - Top flange ring- 17 diameter X 1 1/8" width

     - Gas outlet square tube to cyclone inlet

     - 1/2" close nipple

     - Cover plate for ash clean out port

     - 5/16 x 5/8 bolts for ash port (4 count)

     - 5/16 wing nuts for ash port (4 count)

     - "Rocket fin" legs (4 count)

     - 5/16 nuts for bottom end ring (10 count)

     - 3/8 bolts for leg attachment (8 count)

     - 3/8 nuts for leg attachment (8 count)

     - 1 1/2" female pipe coupler (cut in half)

 

   

Ash Grate parts:

     - Perforated steel disc

     - 1"x 10" black pipe nipple

     - 4 ct. 1/2"x 1/2"x 5.5" sq. tube supports

     - 2 ct. 1/2"x 1/2"x 2 7/8" sq. tube pieces

     - 1 ct. 1/2"x 1/2"x 4" sq. tube

Turning handle:

     - 1" cap

     - 1 ct. 1/2"x 1/2"x 9.5" solid rod for turning handle


II. Building the Gas Cowling

 

A) Attach 3/8" weld studs to the gas cowling.

  • Weld:  gas tight.
  • Purpose: These weld studs will attach the Rocket Legs to the Gas Cowling.
  • Fit weld studs through holes in the gas cowling, screw down 3/8 nuts on outside of cowling to ensure proper alignment.
  • Tack weld them inside the cowling, then weld around the weld stud on the inside of the cowling.
  • Orientation: These studs are at the 'bottom' of the gas cowling.

(*picture from earlier version)

 

B) Weld (10) 5/16 nuts to bottom end ring, then tack ring into gas cowling.

  • Weld: gas tight.
  • Affix nuts to ring with 5/16 bolts.
  • Orientation: These bolts will face toward the inside of the gas cowling.
  • Weld nuts all the way around, then remove bolts.
  • It is wise to clamp the ring down to prevent warping from heat. Also, alternating your welds across the ring is suggested to distribute the welding heat evenly.
  • Clamp bottom end ring into bottom of gas cowling cylinder or press together in sections and tack. Nuts need to be inside the cowling. Progress around the bottom seam in one direction, making sure the vessel tube is tight onto the end ring.

    

 

 

C) Tack top flange ring onto Gas Cowling

  • Weld: tack. 
  • Orientation: No special orientation. Use any tab and slot position.  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 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.

 

 

D) Side seam of Gas Cowling

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

 

 

E) Assemble gas outlet and tack onto Gas Cowling

  • Weld: gas tight.
  • Weld the 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.
  • 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 cockeyed when fully assembled.
  • Clean up flange holes with a 11/32" drill 

 

     

 

F) Weld 1 1/2" coupler (cut in half) and 1/2" close nipple into corresponding holes on Gas Cowling 

  • Weld: gas tight.  
  • Orientation: the 1/2 close nipple is considered the 'front' of the gas cowling.
  • Keep 1/2" nipple at 90 degrees to cowling

 

    

 

G) Fully weld all tacked joints (cowling side seam, gas out tube, top flange, bottom flange).

  • Weld: gas tight
  • Stitch weld in short sections to prevent warping.
  • Tolerances: Weld ONLY on the underside of the gas cowling to the top flange ring.  No welding on the top joint side of the flange, the face of this flange. will need to seal in contact with a second flange.
  • Tolerances: Make sure the weld for the bottom flange ring will not create a stand-off for the lower weld stud for the Rocket Legs.
  • Be careful to not warp the top flange when welding the gas outlet into place. 

 

 

 

 

III. Building the Rotary Ash Grate

 

 A) Clamp perforated disc with a consistent 1/2" cavity beneath it, insert 1"x10" pipe in center hole

  • Weld: Tack/Structural 
  • Orientation: The perforated disk is considered the top of the assembly.
  • The 1/2" cavity allows the center pipe to protrude through the disc to its proper place. Placing several scrap pieces of 1/2"x 1/2" square tube, plywood or other similar material under the disc can make a good support for this part of the process. Make sure the disc is amply supported such that it stays flat when clamped and welded. Its hard to see in the photos, but that is what we are doing under the disc.
  • Array and clamp the 5.5" long square tube supports in a cross formation, each tube at a 90 degree offset from the last, with each meeting and touching the center pipe
  • Align the center pipe such that it stands perfectly plumb
  • Tack parts in place. DO NOT tack the top of the joint where the square tube pieces touch the pipe. This small area needs to remain unwelded to allow a tight fit between the ash grate assembly and its through hole in the bottom of the gas cowling

 

 

2. Support Arms

  • Weld: tack/structural. 
  • Orientation: the support arms will be underneath the grate. 
  • Make sure to keep center pipe perfectly plumb, as it will want to wander around from the weld heat. Bend it back to true and keep checking its alignment with a square as you weld it.
  • Weld at the midpoint of these struts in addition to the two welds per side shown in the photo.

 

3. Sweep Arm

  • Weld: structural
  • Orientation: the sweep arm is on the bottom of the ash grate. 
  • The side struts are 2 7/8" long, the cross piece is the 4"

 

   

 

B) Weld (4) 5/16" weld studs into ash port holes in bottom end plate. (Pictures coming soon!)

  • Orientation: Bolt will extend downwards to the outside of the reactor.
  • Weld: air tight.
  • Temporarily install ash port plate with wing nuts to check tolerance. Clean up holes in ash port cover with 11/32" drill if necessary.
  • Adhere the weld stud to the lid.
  • Weld included tubing to the outside of the bottom end plate EXACTLY over hole in center and EXACTLY 90 degrees to the plate- alignment is very important. The ash grate handle will protrude downwards through this tube, and the tolerances are VERY tight. Precision is required to allow the handle and grate to turn properly inside the cowling without binding up. It is helpful to use the ash grate to hold the tubing in place. 

 

4. Weld turning handle to cap

  • Weld: structural.
  • Weld the arm to the 1'' cap. Make sure the arm is even. 
  • Note: The inside of the cap is considered the inside of the reactor. Make sure the weld does not burn through the cap to the inside. 

 

 

 

 

IV) Bottom Lid for the Gas Cowling

 

  • Weld: gas tight
  • Orientation The threads of the weld studs are facing to the outside along with the grate tube.  
  • Part: The lid of the gas cowling has the port hole similar to the reactor lid, but has one 1'' hole in the center.
  • Tolerance: The rod of the grate must be able to turn inside this middle 1'' hole in the gas cowling bottom lid, double check that it fits, you may need to file out rough edges.

  • Tolerance: Make sure the grate tube and weld studs are welded on straight.

 

 

  • Bolt the cover plate over the port using wing nuts and the weld studs. Bolt the lid down to the gas cowling to prevent warping. Weld the studs to the lid. 
  • Flip the lid around so the weld stud threads are facing upwards. Locate the 2'' grate tube.
  • Line up the grate tube to the bottom lid using the grate itself to stabilize it during welding. Weld.

 

Back to Fabrication Instructions v3.5

 

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