Issue 1: Hopper width doesn’t match

We won’t load the right amount.

We can either make the drawer taller than 6”, wider than 6”, or we make the hopper seat differently

Cut the hopper so it’s wider

Cut the hopper mount base

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Issue 1: Hopper width doesn’t match

Cut the hopper so it’s wider

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Cut the hopper mount base

Widen hopper base here

Issue 2: Length of Rotor with 1” Nuts on ends

The nuts are about 0.875” tall.

Longer for nyloc

If we use shaft collars on the outside of the mixing chamber or bearings that clamp on the shaft then we can design the rotor to not use threaded rod and nuts on the outermost faces.

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Issue 2: Length of Rotor with 1” Nuts on ends

Proposed Solution:

Instead of threaded rod and nuts, use regular 1” rod or 1”OD pipe and use set-screws to retain it on the disc.

Use loctite so they don’t back out?

This also helps us avoid the issue of the external nuts clamping down on the hammers and prevening free spinning. Not an issue if you reduce the hammer tube length enough but it would be best to make those only slightly under sized.

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Added tapped hole

Issue 2: Length of Rotor with 1” Nuts on ends

Proposed Solution:

Nuts on inside of disc

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Needs to be explored

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Issue 2: Length of Rotor with 1” Nuts on ends

Proposed Solution:

Ultra fancy rods:

1 end rotor disc is tapped. The others are clearance for rod. Threaded rod welded to inside of rod to screw into last rotor.

Slotted pipe head nests in last rotor and can be imacted tight

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Issue 3: no CNC. Design for Lathe

Alternative Rotor Build Approach -Making clamshells

1. Clamshell ears are .5x1.5 stock
2. Machine DOM to 3.375” length
3. Cut ears to 3.25” length
4. Drill bolt holes in all 16 ear plates
5. Slide DOM onto shaft
6. Sandwich two ears with 5/16” spacer
7. Center ears and weld to DOM
8. Slide DOM off shaft
9. Bandsaw DOM in half down center of gap in ears
10. Grind sliced DOM flat to the ears
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Alternative Rotor Build Approach -Making 7” Discs

(OK Method)

• Start with ½” x 7” stock
• Drill center hole 1/8"
• Torch outer diameter
• Stack all 5 discs using center hole to align
• Weld or fasten discs together
• Mark 4 1” holes on top disk
• Drill out the holes while disks are fastened together
• Separate disks.
• Bore out center hole to 2.010” on lathe

Alternative Rotor Build Approach -Making 7” Discs

• Start with ½” x 7” stock at 7” lengths
• Tack weld the 5 plates together
• Drill the center hole 1/8" or similar
• Lay out the 4 other holes and center punch them
• Drill out the 4 holes to half inch
• Fasten the 4 holes together using half inch bolts. The plates are now welded and bolted together
• Drill the center hole out to 1” or similar
• Use a bandsaw or grinder to cut off the 4 corners of the 7” plates
• With a large bolt fastened to the center hole, mount the plates in a lathe. ½” bolts still in 4 holes
• Turn to 7” OD
• Mount the plates in the lathe and bore the center hole to 2”
• Separate the plates

BETTER METHOD!

Alternative Rotor Build Approach - initial assembly

• Loosely Assemble the Rotor
1. Slide a disc on shaft
2. Loosely clampa clamshell set next to disc
3. Next disc
4. Next clamshell set
5. So on until you have all discs and clamshells on shaft loosely
• Use 1” threaded rod with 1” nuts to pull disks and clamshells tight and to align all 5 disks.
• Tighten clamshells
• Check the 4 gaps between the plates using calipers
• Adjust using nuts -
• need 40nuts if each plate has nuts on both sides
• Or 8 nuts if only using outermost points to clamp

Alternative Rotor Build Approach - initial assembly

All 4 threaded rods installed with outermost nuts clamping

All 16 1/2x1.75” nuts installed and clamshells tight

Ensure that gaps between plates are consistent.

Weld clamshells to plates

Use tacks to reduce warping and make shaft removal easier

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Alternative Rotor Build Approach - initial assembly

Remove 2” shaft

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Alternative Rotor Build Approach - initial assembly

Torch discs in half

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Make sure you mark the aligned faces for future reassembly

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Mark aligned faces

Alternative Rotor Build Approach - initial assembly

After torching, grind discs flush with clamshell ears

You now have two halves of the rotor

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Soil Mixing Chamber - Design for tight fit of rotor

Want minimum buildup of material but also want ease of fabrication.

Here the blue is removable front door.

This is a three plate fit. If we want we can do a fully rounded bottom by welding flats together in an arc. 1.5” flat for example.

This would complicate the removal of the rotor

We can weld small plates in where the gap is greatest. The joint between the door and the

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This plate can be moved away from the rotor more but i was thinking to weld it in permanently

Soil Mixing Chamber - Design for tight fit of rotor

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Blue circle is 16.25”OD

Soil Mixing Chamber - Soil Escapement

The 3” angle at the back end is going to be problematic for soil ejection.

Can we lose the 3” on the other end of the mixer?

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Blue circle is 16.25”OD

Soil Mixing Chamber - Soil Escapement Rework

Here’s a way to get rid of the 3” angle. But we have to extend the drawer to 3’

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Drawer Build

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Move 1” shaft ½” to the right to allow head of 1” bolt head to mount the roller.

Roller

Rotor Build Rough Outline

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1. Make Tube. Slit 2” ID tube in half
1. Use torch
2. Note that material ablation is critical to proper clamping when OD_shaft=ID_tube
2. Make Clamp. Cut holes in tabs and weld tabs
• Weld with 2” shaft in place to assure proper spacing of tabs so they clamp properly

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Tube

2

Clamp

Clamp Bolt Holes

Rotor Build 2

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• Make Disks. CNC or hand cut the 5 disks
• Make sure to cut out corners (so disks fit on the flanged shaft)
• Partially slit the disc on the inside of the disc next to where the clamp flanges will be
• Make Disc Rotor. Weld disks onto clamp.
• Clamp bolt holes are between disks.
• After welding, finish the slit started above so that the clamp can be separated.

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Disks

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Disk Rotor

Rotor Build 3

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• Unbolt rotor into 2 parts
• Insert the threaded rods and hammers on each half of rotor
• At this point, 2 hammermill rotor halves are ready for mounting in hammermill

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Hammermill Chamber Requirements

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• Modular chamber has 3 parts - body, top, removable back
• Hammermill can be opened from the top to replace blades
• Hammermill can be opened from the bottom to clean the chamber
• Body is ½” steel
• Body has sufficient volume to handle mixing of 20 lb of soil
• Chamber has an input from a cement hopper
• Chamber sits on ground
• Inner chamber fits 16”x16” rotor
• Opening on top is 12” wide

16”

Drawer

Opening for injecting cement

Top opening for soil

Body of hammermill

Removable back

16”

Deflector

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Plate

Loading/Unloading Concept

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Side View. Ejection

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Hammermill

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Chamber Loading

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Hammermill

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Drawer Loading

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Hammermill

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• Use 1 cylinder only to load and eject soil.
• Auger loads cement into chamber.
• Pros: Shorter Drawer
• Cons:Added cycle time

Cylinder mounted in inner part of drawer to reduce overall length of hammermill

2 position load/unload concept- short stroke

Load drawer/Eject

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Hammermill

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Unload drawer/mix

Hammermill

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Mid stroke

Hammermill

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• We could use a shorter stroke cylinder - as low as 6”
• Why use 14” cylinder if 6” could work? Gap in my understanding
• This is how the mixer was initially drawn, not sure why a third position was added.
• DOESN’T WORK BECAUSE SOIL ESCAPES DURING LOADING

2 position load/unload concept - long stroke

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Load drawer/Eject

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Hammermill

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Unload drawer/mix

Hammermill

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Mid stroke

Hammermill

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• Use 12” cylinder or 14
• Two position - extended, retracted
• Auger into chamber beginning on start of extension and ending after delay for soil load
• Pros: Simultaneous loading of hopper and eject of material
• Cons: Long drawer

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Load drawer/Eject

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Hammermill

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Unload drawer/mix

Hammermill

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Mid stroke

Hammermill

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