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10/15/2021 2:19 AM
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10/14/2021 10:06 AM
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Atypical 300gm spouting bed roaster
scotthal
Design goal is a 300gm capacity spouting bed roaster - top load, bottom dump; off_the_shelf components; requiring minimal hardware skills. Initial lashup, shown here, is proof_of_principle for roast chamber capacity & bean circulation. Heat gun element is in the downtube for the airflow restriction, but hasn't been hooked up - I didn't want to waste time stripping paint, or money on hi-temp wiring, until I knew the basic concept would work.

Construction is straightforward - only hard bits, thus far, have been drilling the chromed steel canning funnel for the pop riveted 'ears', & trimming the helically wound toroidal air diffuser to fit the throat of the canning funnel.

I've tested the rig w/[150gm ... 300gm .. 450gm] green, & - 10% = [135gm .. 270gm .. 405gm] pre-roasted (old-junk) loads. Circulation looks good in all cases - I get spouting around the downtube, & a uniform cascade around the periphery for the 'representative' loads at blower voltages below 100VAC (~200W). Goosing the voltage above 110VAC transitions to a more chaotic regime - it looks like a hiccuping fluid bed implentation. Push it hard enough (140VAC), with a large enough (400gm+) load, & you start seeing the occasional flier.

Roast chamber - bottom to top:

2-5/8" OD jam jar lid. Stripped the plastic seal, chipped the paint, added a circular gasket of silicone baking mat
5-1/4" ID canning funnel (2-1/4" tapered throat, w/lip). Added ears - punched the 1/4" pegs out of a pair of shelving brackets, pop riveted to the funnel from the inside out. Knocked out mandrel remnants, & sqwooshed with a C-clamp to allow room for the support strut(s) nut(s).
#352 Silicone O-Ring - tamped it in betwixt funnel & glass using plastic bicycle tire irons
Coleman (295) R690B048C replacement globe - upside down
Upper extension - cannabalized a standard 502x716 ... can, selected for it's deep : widely separated reinforcement ridges, diameter, & the fact that I really didn't need the Legos it had held for 20+ years. Chopped off the the requisite bit (~3" total) using a Dremel w/cutting wheel. Cut immediately above a ridge - smooth section acts as a sleeve, next ridge seats against the top of the glass chamber. Flared to fit the narrower (bottom) end of the Coleman globe, utilizing classic iterated percussive metal forming technique. Pop riveted 1"x1" angle ears - they're needed to stabilize (not compress) the roast chamber stack.

Air manifold :: heater - back to front:

2.5 gallon, 4A Kenmore shop vacuum; 1-1/4" flex hose
1-1/2" - 1-1/4" flexible PVC connector
7" black PVC kitchen (1-1/2") waste arm
7" chromed brass kitchen (1-1/2") waste arm
12" chromed brass kitchen (1-1/2") waste tailpiece - cut down to 9", after running initial test loads
Deflector - Friction fit back_to_back 1-1/2" ID shallow flanges, w/10mm strip of springy soup can to maintain registration.
Diffuser - 5/8" x 6-1/2", 0.054"D extension spring. Cut to length, "stapled" into shape w/bits of paper clip, lashed to the base of the vertical tailpiece with more of the same.
Heat gun element (Master Appliance MASHAS-403K, not yet connected) & mica sheet are resting on the cotter pin.

FWIW - will need a metal screw for the tailpiece :: waste arm junction before I switch on the heat.
scotthal attached the following images:
p1000403.jpg p1000401.jpg p1000405.jpg p1000395.jpg p1000388.jpg p1000410.jpg p1000416.jpg p1000412.jpg p1000414.jpg

Food for thought; coffee for concentration
oldgearhead
Kool! The only thing I don't like is the Hills Bros can. LOL
How are you handling the chaff? Is bean cooling going to be at a separate station?
I can't wait to see a video of this in action..
No oil on my beans...
allenb
This is turning out to be an intriguing fluidbed! Looking forward to seeing some beans browning in it.

I've only seen one commercial roaster that appears to be similar in design and seems to have a lot of positive attributes.

Keep us posted
allenb attached the following image:
topfiredfluidbed.jpg

1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
LongLeafSoaps

Quote

scotthal wrote:

Design goal is a 300gm capacity spouting bed roaster - top load, bottom dump; off_the_shelf components; requiring minimal hardware skills.


Wow! Very nice build! I really like the use of spring at the dump area...just make sure to burn off any coating like galvanizing, or zinc before roasting. Also, the silicone baking mats can catch on fire if the heat source is close enough.... (ask me how I know, lol!)

Can't wait to see it in action as well! ThumbsUp
Carpe Diem With Coffee
scotthal

Quote

oldgearhead wrote:

How are you handling the chaff? Is bean cooling going to be at a separate station?


Figure I'll handle bean cooling in place - thermal mass of the roaster is relatively low, & kicking the blower voltage up for "chaotic" circulation should drop bean temps pretty quickly.

Chaff - well, the rig isn't going to fit under my kitchen hood. If it ends up on the back deck, will just whip out a leaf blower after_the_fact.

Not sure yet whether air flow during the roast cycle will be sufficient to loft the chaff out of the main chamber - wouldn't be surprised if it stacks up on the topside of the deflector, or embedded in the bean circulation.

Need to see what happens - and what my effective thermal budget turns out to be. If I have to recirculate, pickoff for the hot air may be able to catch a significant portion of the chaff.
Food for thought; coffee for concentration
scotthal

Quote

allenb wrote:

I've only seen one commercial roaster that appears to be similar in design and seems to have a lot of positive attributes.


Could you provide a link? Picture suggests that it is a true fluid bed - flat bottom to the chamber is consistent with a uniform/pressurized plenum. Haven't seen it's like before ... darn, thought I was being original.
Food for thought; coffee for concentration
allenb
Here you go.

http://forum.home...ad_id=3020

Looks like this one has a different approach for achieving bed rotation using two air entry points (two tubes entering from the top aiming at different angles).

https://www.youtu...M2o6uvBLZA

Allen
Edited by allenb on 01/24/2016 10:45 PM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
scotthal

Quote

LongLeafSoaps wrote:

Wow! Very nice build! I really like the use of spring at the dump area...just make sure to burn off any coating like galvanizing, or zinc before roasting. Also, the silicone baking mats can catch on fire if the heat source is close enough.... (ask me how I know, lol!)

Can't wait to see it in action as well! ThumbsUp


Thanks for the heads up on the silicone baking mat! Design sketch calls for a thermocouple stud centered in the jam jar lid - figured I should keep the plenum temp below 480'F; suspect yr experience(s) would confirm that.

Have avoided zinc & galvanized for the construct - spring is nickel plated; everything else is either chrome or brass. Plan to cook it a bit before risking good beans (& heavy metal poisoning)...

Dump spring ... darn. That's a temp solution. Wanted a default : neutral : closed setup during the prototype phase. Lever arm (against stiff springs) is a bit clunky. Original design sketch calls for either a locking lift arm for the chamber, or a fixed chamber w/moveable air feed. Hi-temp wire may take awhile to cross the Pacific. Will probably try prototyping both variants in the interim.
Food for thought; coffee for concentration
LongLeafSoaps
Thanks for the heads up on the silicone baking mat! Design sketch calls for a thermocouple stud centered in the jam jar lid - figured I should keep the plenum temp below 480'F; suspect yr experience(s) would confirm that.

Have avoided zinc & galvanized for the construct - spring is nickel plated; everything else is either chrome or brass. Plan to cook it a bit before risking good beans (& heavy metal poisoning)...

Dump spring ... darn. That's a temp solution. Wanted a default : neutral : closed setup during the prototype phase. Lever arm (against stiff springs) is a bit clunky. Original design sketch calls for either a locking lift arm for the chamber, or a fixed chamber w/moveable air feed. Hi-temp wire may take awhile to cross the Pacific. Will probably try prototyping both variants in the interim.[/quote]

I think the springs on the arms are fine, I meant the spring at the bottom of the heat tube..the one that keeps the beans from getting stuck while roasting...great idea! ;-)

Chrome plated can be worrisome too from what I have learned via blacksmithing and a couple good links for info are:

www.iforgeiron.com, and www.anvilfire.com...galvanized is the really bad one though. I would really only worry about it getting into your lungs if you get it hot enough to flash off, but heavy metal poisoning is a real risk at high baking temps..I have seen this discussed on several builds here..

I think Allen (I think it was Allen) had a good link for stainless steel tubing.

You would be surprised at how little air it takes to blow chaff all over the place...it is as light as feathers ;-)
Maybe build a box that surrounds all sides put the front and use a dryer vent with a computer cooling fan to suck the chaff into a bucket, the bucket would need a screened vent somewhere...there are some pretty awesome cyclone builds on here for dealing with the chaff issue. You could do a quick forum search. If your beans are being blown enough in your roasting chamber to create a fluid action, you will have a problem with chaff blowing out of the roast chamber I'm sure. O.o

I think the silicone mat is designed to withstand more of a radiant type heat, rather than direct heat...guess you could test it out sans beans first...


ETA: as far as original design/idea goes, sorry about that... =( I just had the same thing happen to me, only it involved a sock knitting machine.... it can be very disappointing I know, but don't let that discourage you from finishing this build..it is still your design! ThumbsUp
Edited by JackH on 01/25/2016 7:26 AM
Carpe Diem With Coffee
allenb

Quote

allenb wrote:

Here you go.

http://forum.home...ad_id=3020

Looks like this one has a different approach for achieving bed rotation using two air entry points (two tubes entering from the top aiming at different angles).

https://www.youtu...M2o6uvBLZA

Allen


There appears to be three air delivery tubes set at an angle for creating the spin. I originally thought the one on the right was aiming straight down but it most likely is at the same angle as the two on the left but hard to see it in 1D viewing.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
LongLeafSoaps

Quote

allenb wrote:

http://forum.home...ad_id=3020

There appears to be three air delivery tubes set at an angle for creating the spin. I originally thought the one on the right was aiming straight down but it most likely is at the same angle as the two on the left but hard to see it in 1D viewing.

Allen


I am sure your right about the angle of the third tube matching the other two...if you look closely at 0:42 you can see where it looks like the tube is at an angle...

Catchy, fun music in that video too ThumbsUp
Carpe Diem With Coffee
scotthal

Quote

LongLeafSoaps wrote:

I think the springs on the arms are fine, I meant the spring at the bottom of the heat tube..the one that keeps the beans from getting stuck while roasting...great idea! ;-)



Ah! You mean the "helically wound toroidal air diffuser" ... was tempted to leave that phrase hanging (sans supporting photos) ... figured that I would get a few queries, if anyone actually read the post.

Yaah - using an extension spring is a heckuvalot less labor intensive than drilling a perf plate. Centers the down tube, plugs the funnel throat, & does a darn good job of diffusing :: distributing the air stream. Downsides? may lose temper at the target operating temperature (~450'F).

Bit disappointed tho' - no one has queried the "classic iterated percussive metal forming technique" yet. Guess that one is overly obvious.
Food for thought; coffee for concentration
LongLeafSoaps
Oh, you mean bashing it around with a hammer, LOL! Roflmao

(so, you are a Big Bang fan?)
Edited by JackH on 01/27/2016 3:35 AM
Carpe Diem With Coffee
scotthal

Quote

LongLeafSoaps wrote:

Oh, you mean bashing it around with a hammer, LOL! Roflmao

(so, you are a Big Bang fan?)


Guess the phrase was a bit blatant - yaah, I repeatedly hit it with a hammer.

Not a TV watcher, haven't ever tuned in to Big Bang ...

Decided the dump : lever arm was too clunky. Also, figured I had some time until various bits & pieces arrived (China, Hong Kong, whatever, ...). Am reworking for a 'fixed' chamber, movable air feed setup in the interim.

Always planned to depopulate the metro cart, & utilize a 1"x8"x4ft board for the backplane; probably clamped to an old wireframe microwave cart. Specific hardware harness was in flux, but the plank's constant ... & may need an aluminum veneer, for the radiant heat load.
Food for thought; coffee for concentration
LongLeafSoaps

Quote

scotthal wrote:

... haven't ever tuned in to Big Bang ...

Decided the dump : lever arm was too clunky. Also, figured I had some time until various bits & pieces arrived (China, Hong Kong, whatever, ...). Am reworking for a 'fixed' chamber, movable air feed setup in the interim.

Always planned to depopulate the metro cart, & utilize a 1"x8"x4ft board for the backplane; probably clamped to an old wireframe microwave cart. Specific hardware harness was in flux, but the plank's constant ... & may need an aluminum veneer, for the radiant heat load.


A lateral side to side mechanism for dumping is a bit more elegant looking imo, and would work well with the canning funnel also..Have you thought any more about chaff collection/bean drop chute from the top? An off center canning funnel would be perfect in ss...I suppose you could just invert another funnel, run your blower pipe thru the existing spout, and cut an opening for a cyclone or some other such collection system?

I figured you were a Big bang fan because of the , "What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?" question from the show, lol!

If you get some aluminum for a veneer, perhaps get a tad more to replace your coffee can ;) , and perhaps you could procure a nice race car red tool cart like turtle uses for his roaster? Looks great, is compact, has a shelf for your fire extinguisher & supplies, and can be wheeled away for storage when not in use Grin

ETA: interested to see what you come up with!
Carpe Diem With Coffee
oldgearhead

Quote

>snip
Decided the dump : lever arm was too clunky. Also, figured I had some time until various bits & pieces arrived (China, Hong Kong, whatever, ...). Am reworking for a 'fixed' chamber, movable air feed setup in the interim.
>snip<

I've been using a J-tube to move the coffee into a quart Mason jar for around 5 years.

btw - The attached file is 241KB at 800x531.
...and 'fakepath' shows up in file name
oldgearhead attached the following image:
dsc_4334_1.jpg

Edited by JackH on 01/29/2016 4:59 PM
No oil on my beans...
Lawnmowerman
Very impressed.ThumbsUp
Bad coffee prevails when good coffee roasters stand by and do nothing.
scotthal
Minor tweaks to the support structure, whilst waiting on a slow ship(ment) from China & a few items from Amazon.
scotthal attached the following image:
p1000426.jpg

Food for thought; coffee for concentration
LongLeafSoaps
scotthal...I like how the dump opens up with the bench clamp now...cleaner design...very clever ThumbsUp
Carpe Diem With Coffee
scotthal
Thanks! Vertical latching clamp was always part of the design (it appears in the first post of the thread). Needed a more stable harness (& some dimensional decisions) for the install. Still in flux - need to clamp or bolt it's back corner, and finalize the thermocouple mount.

That one is a head scratcher... I've drilled the port cover for a 15mm TC stud (M6 threading); 1-1/4" compression spring (~5kg) suffices for the seal. But it ain't positionally stable. Figure running a 1/4" rigid tube up through the spring should do the trick, but am waiting on the parts... amazing how sparse the selection is at Lowes & HomeDepot.

C-clamp on the lower 4" angle is also a temporary kludge - requisite replacement (27kg horizontal latching clamp) is on the slow boat.
Edited by JackH on 02/12/2016 3:22 AM
Food for thought; coffee for concentration
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