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Is one lonesome vac motor blowing and cooling in this 5kg setup? Any stirring vanes needed?

It will be breathtaking, I'm quite sure!

CHAD

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I already use one of these on the 400mm cooling bin it should do the trick on the 800mm bin. Not going to bother with stirring vanes. I see the big sivetz roasters don't use stirrers.
http://www.topmaq...d=WWDU1100

On the roaster it's going to take 2 vac blowers to do the job.

Rob

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5/6 kg roast chamber. I went square this time. I am hopeful that this unit might do 7 kg. Which means if I make one in the future that is 3 times as wide it will around 21kg. The bottom section of this roaster should be finished next week.

Rob

Ok I have attached the photo but it won't show?

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Looking forward to seeing the new RC design. what size square tube did you end up using.
sean

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The new RC is 200x200 square at the bottom then 200 X 320 at the top. For some reason I can't get the photo to show.
Rob

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Ok worked out what I did wrong.
Nothing fancy for dumping the beans it will be hinged. It will slide back into place at the top to a vent chaff collecting system. Still working out the details for that.

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That qualifies as art! Beautiful stuff! !! - Scott

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Whoa! Magnificent hopper, Rob! There's even plenty of room for a viewing glass.

I really appreciate your inspiring designs.

CHAD

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I am newbie so I hope this is not redundant. I was trying to figure out in Rob's design what seals the roast chamber to the furnace section? Is the weight of the RC enough to create a a good enough seal.

And on another note I found a place in the US that sells seivert torch heads. Its ngtmodels.com. They shipped out very quickly.

Thanks

Ryan

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Welcome Ryan! Gravity is what holds Rob's roast chamber on. It's made of steel, very heavy. If you've seen his video, he just sets it on the furnace. My similar (but different) design also uses gravity.

CHAD

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So gravity is enough? Is there no air leakage between the RC and furnace? Does anyone see a problem with the furnace section being 8" as opposed to 6"?

Chad,

Do you have any pics of your roaster posted I would be curious to see different ideas. I am just about to start building a roaster. Basically plan to copy Rob's ideas, but would love to see any variations that might be easier or better.

Thanks,

Ryan

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Very slight leakage on my roaster. Rob has his down to a science with much better fabrication, so I'm sure it's negligible as well. 8" instead of 6"... there has been some discussion about reducing the airspace between the heat element and the roast chamber- theory being that more air acts like a bigger spring cushion, causing bouncing of the bean mass and reducing flow efficiency... but it's mostly theory, and you may not notice any trouble whatsoever.

My roaster is NOT easier or better:
http://forum.home...post_20940

Another build thread:
http://forum.home...ad_id=1905

Please feel free to start your own thread specific to your roaster!

CHAD

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RoasterRob wrote:
per row 9 mm apart, rows 5mm apart, offset 4.5mm. means that the spacing between holes is 6.7mm from memory. Sort of a diamond pattern formed by any 4 holes. with any side being 6.7mm hole centre to hole centre...

I'm investigating putting together a 1lb gas fired fluidbed based on your assymetrical 4" diameter RC you mentioned quite a while back.

I understand the 25% perf plate area (at a 45 degree angle) and 1/8" holes but I'm having trouble following the "per row 9mm apart, rows 5mm apart, offset 4.5mm". Could you elaborate on this as I want to duplicate your perf plate exactly.



Allen

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In my impatience I broke out the abacus and slide rule and here's what I've come up with for Rob's neat asymmetrical round RC for a 1 lb fluidbed:

- RC diameter = 4"
- RC bottom is sloped at a 45 degree angle down to the point where it meets the perf plate which is flat.
- perf plate area is 25% of a 4" circle or 3.142 square inches.
- perf holes diameter = .125" or 3.175 mm
- holes center to center approximately .318" or 8 mm. (diamond pattern).
- perf open area % = around 14%
- total combined open area = around .4418 square inches.

For calculating perforated metal % open area (for 60 degree staggered center) you can use this formula: (hole diameter squared x 90.69) ? (hole center to center distance squared).

Allen

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Hi Allen

Sorry missed your posts in November I would have replied if I had seen them at the time. Feel free to PM thru HR. I have a template somewhere in an Autosketch file. Most of what you worked out looks about right.

Rob

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I also used Robs design, to seal the RC to the bottom I used a band of insulating tape around the bottom and then a 2" wide thin aluminum as a clamping band. When I put the RC on top I just tighten 2 6" hose clamps to keep the RC from moving around to much.

I actually need some air leaks since my VC is too powerful for smaller roast, even with the dimmer on its lowest setting an a screen over the inlet.

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I'm curious how did this roast chamber work out? Did it work well for 5-7 kg? How high is it? 1 meter? Did it require more than the 2941 burner?