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All About the Bubble Bed Roaster
seedlings
Top  #26 Print Post
Posted on 04/11/2010 8:08 AM
Allen, looks like from the video that you could dial down the CFMs and make it a little more efficient while still circulating very well. Nice!

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
allenb
Top  #27 Print Post
Posted on 04/11/2010 9:38 AM
I'm betting as I'm sure you are that the 1.6lbs of roasted would be launched to the top if the air didn't get dialed down as things progress but maybe it's different with the bubblebed. I'll give it a try as soon as I get some roasted I won't feel bad about sacrificing.

The rig won't make the next step to actual roasting. It's a hobby lobby clear plastic paint can with a very thin sheet metal bottom (made it real easy to drill the 300 + holes). I didn't want to go any further with experimenting but now I'm more curious than ever to see how a roast would turn out.

Chad, I was able to get good agitation at lower air flow except for the perimeter. As soon as I dial it back enough to stop perimeter channeling there ends up being areas that just sits there taking way to long to move back into the flow areas. I need to make more adjustments to the hole pattern at the perimeter.

I'll update as things progress.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
klemenv
Top  #28 Print Post
Posted on 04/14/2010 4:32 AM
Great prototype, Allen. What kind of blower are you using to achieve 150 CFM?
 
allenb
Top  #29 Print Post
Posted on 04/14/2010 8:31 PM
It's a single stage commercial VC motor I scavenged out of a trashed VC:

http://vacmotors....447/detail

After looking up it's specs it appears the max cfm is 143 which I will assume to be with it at full rpm and pushing against 0" H20. If this is the case then I was nowhere near 150 cfm because I was running it at 70 volts when making the video. I want to run it again when I can find a way to measure velocity with a pito to calculate cfm.

In a previous post I stated that I thought you would need an 8" dia tube to get a bubblebed working with a 1kg charge. After working with the 6 3/8" dia paint can with a 2lb charge I think this would work fine with 1kg.

The perf pattern I used was similar to the one with 4 high density areas shown in one of my previous posts not the one with 3. I need to do some more experimentation with different patterns to optimize agitation.

For easier experimenting I'm going to find some high % open area perf metal to replace the bottom of the paint can and tape over the bottom of it so I can cut out the patterns using an exacto knife. This will be much easier than drilling all those holes several times.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
allenb
Top  #30 Print Post
Posted on 05/19/2010 7:51 PM
I've come up with an alternate perforation layout which has a slightly larger high density perf area which widens as it gets closer to the perimeter. I also made the outer 3/4" perimeter ring slightly higher in density than the inner low density areas. I did this due to less than acceptable bean lift at the outer perimeter wall layer.

Hole dia: 5/32"

Hole count as follows: low density holes: 150, high density holes: 200. This is still close to Jobst Zoellner's ratio's from his patent docs.

I've attached the new smudged perf pattern below the Youtube video

I think the bean lift is more consistent with less perimeter channeling although the perimeter layer could still use a few more holes.

Allen

allenb attached the following image:
perfplateoption2bubblebed.jpg
Edited by allenb on 04/02/2023 7:25 AM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
seedlings
Top  #31 Print Post
Posted on 05/19/2010 8:55 PM
It seems like your original circular patterns had a more natural flow.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
allenb
Top  #32 Print Post
Posted on 05/19/2010 9:29 PM
Good observation. After looking over the first video it definitely was more stable.
I had to crank up the VC output on this one higher than the first setup to get the outer layer to flow which is probably why the jumpiness.

When I had the output the same as the first test, the pattern was very stable but the outer layer suffered.

I'll increase the outer hole count and re-test but I'm getting real tired of drilling holes!

It may end up the first pattern with a little less outer holes or moving the outer holes inward a little may work as good or better?

I'll update soon.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JETROASTER
Top  #33 Print Post
Posted on 05/20/2010 11:24 AM
Hi Allen,
I recognize your blower(I'm in the vacuum biz). Many of these units have a speed control pcb. Would any of that stuff help your project? -Scott
 
seedlings
Top  #34 Print Post
Posted on 05/20/2010 1:49 PM
For comparison, below is a 1.25# spouting cone. Skip the first half, not much to see there.

Notice: TURN THE VOLUME DOWN BEFORE YOU CLICK
http://video.yaho...66/3428628

CHAD
Edited by seedlings on 05/20/2010 1:52 PM
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
allenb
Top  #35 Print Post
Posted on 05/20/2010 8:12 PM

Quote

freshbeans wrote:
Hi Allen,
I recognize your blower(I'm in the vacuum biz). Many of these units have a speed control pcb. Would any of that stuff help your project? -Scott


Funny you should mention!
I've been wiring and un-wiring a boat anchor of a variac to power the thing which if I had something more manageable and smaller...

I've been putting off building a triac based control RoasterRob pointed me to a little while back due to excuses I won't go into but I'll warn you, I'm a cheap miser.

Please tell more

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
allenb
Top  #36 Print Post
Posted on 05/20/2010 8:22 PM

Quote

seedlings wrote:
For comparison, below is a 1.25# spouting cone. Skip the first half, not much to see there.CHAD


I had seen this video a while back. What were you using for a bottom plate?

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
seedlings
Top  #37 Print Post
Posted on 05/20/2010 9:03 PM

Quote

allenb wrote:

I had seen this video a while back. What were you using for a bottom plate?


Aluminum screen over a ~2" opening.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
JETROASTER
Top  #38 Print Post
Posted on 06/03/2010 10:00 AM
Allen,
Sorry, lost track of this thread. I'll drag in some schematics
and find some goodies for you.
You say 'cheap'...I prefer 'cost effective'. Don't be scared,
I have the worlds largest vacuum graveyard. Scott
 
JETROASTER
Top  #39 Print Post
Posted on 06/04/2010 9:20 AM

Quote

allenb wrote:
Funny you should mention!
I've been wiring and un-wiring a boat anchor of a variac to power the thing which if I had something more manageable and smaller...


Most of PCB's are potentiometer controlled. Will that work, or would you prefer electronic? -Scott
Edited by seedlings on 06/04/2010 10:53 AM
 
allenb
Top  #40 Print Post
Posted on 06/04/2010 1:13 PM
Hey, anything that is lighter than my present 20 lb variac and doesn't take up a square foot of bench space will be a welcome change! Passive or active is ok by me.

Thanks for keeping me in mind,

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JETROASTER
Top  #41 Print Post
Posted on 06/04/2010 1:27 PM
I've got a couple I'll test on a Domel blower. Drop me a shipping address in a PM. It will arrive UPS likely by late next week.
Considering your demos are a benefit to everyone, there will be no charge.

Also thanking Chad for cleaning up my post -Scott
 
RoasterRob
Top  #42 Print Post
Posted on 06/04/2010 8:30 PM
Hi Scott, the PCB will be a Triac based controller. The only problem I have had with units out of vacuum cleaners is that they can't be turned down low enough. This may not be the case for all of them, possibly only the 2 or 3 that I have played with.
Rob
VBM Minimax 2gp, 1gp Reneka Techno, 2 gp la Pavoni Pub, la Cimbali M28, SJ Maz, FB 6kg HM roaster and other stuff
 
JETROASTER
Top  #43 Print Post
Posted on 06/05/2010 8:25 AM
Hi Rob, I'm interested to see how it works. I never actually tried. I've always dumped extra cfm with a valve.
Looking forward, I can see where some electronic control would be useful.
I'm currently working on a 1lb. sample roaster that has no space for a dump valve. So, I guess I better find a pcb that works! -Scott
 
JETROASTER
Top  #44 Print Post
Posted on 06/05/2010 10:27 AM
Question; Can these triacs be altered? -Scott
 
RoasterRob
Top  #45 Print Post
Posted on 06/05/2010 3:52 PM
The triac is controlled by the voltage to the ingate. Replacing one of the resistors with a trimmer (small potentiometer) might be all you need to do. If you read the info here about tuning this dimmer you will get the idea.
http://www.epanor...ml#1kw230v
The trimmer in this circuit (P2) shifts the range of resistance from the main potentiometer (P1).
This particular circuit is the one I used for my VC dimmers, it works perfectly. Better than a kitset dimmer specifically intended for controlling universal motors that I originally bought.

One further comment if you do modify one of these circuit talk to some who knows this stuff. I am not electronics an electronics specialist.

Rob
Edited by seedlings on 06/05/2010 9:19 PM
VBM Minimax 2gp, 1gp Reneka Techno, 2 gp la Pavoni Pub, la Cimbali M28, SJ Maz, FB 6kg HM roaster and other stuff
 
allenb
Top  #46 Print Post
Posted on 06/12/2010 8:02 PM
Scott,
The PCB arrived and I tried it out this morning. Unfortunately it won't make it down to the power level needed.

I'm going to take a stab at changing the resistor as Rob mentioned and see if I can get a bigger turn-down.

Thanks for the PCB! I'll figure out a way to get it to work for me.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JETROASTER
Top  #47 Print Post
Posted on 06/14/2010 7:51 AM
Allen,
I hope it helps in some way. If overall airflow still exceeds what you need, a partial obstruction of the fan intake,
or choking air output may give you the envelope you need.
Obstructing intake will create less CFM overall. Constricting output will reduce CFM, but maintain a higher
pressure. (perhaps reduce bouncing)
I Love this thread. Good Luck! -Scott
 
allenb
Top  #48 Print Post
Posted on 04/02/2023 1:29 PM
I've begun researching the bubblebed again after taking another look at what Typhoon Roasters has been able to accomplish with their bubblebed designs. I'll be working on an experimental .7 kilo bubblebed over the next couple of months.

Here's a video of my original mockup version using an unmodified perf plate pattern which allowed a less chaotic bubbling bean flow pattern.



Another view (overhead)

1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
greencardigan
Top  #49 Print Post
Posted on 04/02/2023 11:46 PM
Looking forward to your new testing!

It's hard to believe that over 12 years have passed since you last posted about this. I miss many of the of the enthusiastic air roaster builders that contributed to the early discussions.
 
Koffee Kosmo
Top  #50 Print Post
Posted on 04/03/2023 5:54 PM
I was looking at the video from above
It looks like 4 flowers pulsating cool
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
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