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Fluidbed Roaster project
cdrake39
Top  #1 Print Post
Posted on 11/05/2019 9:48 AM
Hi everyone,
I've been browsing this forum for quiet some time now and have finally decided to take the plunge and build my own roaster. I have posted regarding "fan/blower sizing" on the r/roasting subreddit, but was directed here as this forum is quite active. Here was my post:

I'm looking into building a small, benchtop coffee roaster capable of roasting batches of approximately 200 grams. It will be a fluid bed design utilizing an 1800W heat gun element paired with a 12VDC fan. Ultimately, the fan and heat source will be controlled via the TC4+ Arduino shield. Since I would like to keep the design as small as possible, I am on the lookout for a compact fan with a sufficient static pressure and airflow to loft the beans during roasting. I came across this particular fan ( https://www.digikey.ca/product-detail/en/sanyo-denki-america-inc/9HV0612P1J001/1688-2189-ND/8285336 ) and was hoping to get some feedback on it's suitability? It has a small 60mm x 60 mm footprint, 7"H2O static pressure, and 66.4CFM flow rate.

I was informed that the fan I had selected likely would not work, and a vacuum motor/blower would be more suitable. So I am now on the hunt for a compact (ideally less than 100mm x 100mm) fan that can be used in a 250g fluid bed roaster and was hoping to find some answers via this forum. I found a Dyson DC16 handheld vacuum in a local buy and sell for $40, which may meet my criteria in terms of size, but I'm unsure about air flow...

This is my first project of this type and I am looking forward to learning from the expertise in this forum. Thanks in advance for your feedback!
 
CharcoalRoaster
Top  #2 Print Post
Posted on 11/06/2019 9:12 AM
Vac motor is definitely the way to go as it will have the necessary CFM to circulate your beans. Look on eBay as I've had luck finding really great motors that have already been excised from their vacuums for the same price range. Both of mine are bypass not flow thru types
 
cdrake39
Top  #3 Print Post
Posted on 11/06/2019 9:45 AM
Thanks for the advice! The more I read, the more I understand why people opt for vacuum motors. I guess my next question would be, would a 24V vacuum motor work? I ask for two reasons - Firstly, the TC4+ is designed for DC fans and this would make control a little easier (no need for a dimmer switch). Secondly, I am looking at the following motor (https://www.ebay....3830540125) as it is fairly compact. It comes from this vacuum -https://www.rowen...2210018532
Edited by cdrake39 on 11/06/2019 3:47 PM
 
JackH
Top  #4 Print Post
Posted on 11/06/2019 3:08 PM
Love those links....
---Jack

KKTO Roaster.
 
cdrake39
Top  #5 Print Post
Posted on 11/06/2019 3:47 PM
My bad, just fixed them so they are clickable.
 
JackH
Top  #6 Print Post
Posted on 11/06/2019 4:10 PM
Thanks, it just makes it easier for everyone.
---Jack

KKTO Roaster.
 
cdrake39
Top  #7 Print Post
Posted on 11/07/2019 8:31 AM
So I opted for this fan (https://www.aliex...b201603_52). I read about another roaster who had great success with this particular fan, so I figured I'd go for it. I have a few other details to sort out, so I didn't mind the long shipping time. Once parts begin to arrive I'll make a post regarding progress.
 
renatoa
Top  #8 Print Post
Posted on 11/07/2019 8:56 AM
Sourced the control board too ?
 
cdrake39
Top  #9 Print Post
Posted on 11/07/2019 9:03 AM
Yep, got that as well!
 
pisanoal
Top  #10 Print Post
Posted on 11/07/2019 9:51 AM
Where did you source the control board from?
 
cdrake39
Top  #11 Print Post
Posted on 11/07/2019 9:54 AM
There are two options on the Aliexpress link - with and without the control board. Or are you referring to the TC4+ board? In that case it was sourced from here: https://www.tindi...-tc4-plus/
 
renatoa
Top  #12 Print Post
Posted on 11/07/2019 11:51 AM
Nope, motor control board.
Noticed it in the pictures, but not the option to buy.
Now I see the seller notes.
 
cdrake39
Top  #13 Print Post
Posted on 01/20/2020 1:24 PM
Hey everyone, rather than start a new thread I thought it would be best to continue off of this one. I have all the parts (aside from the top and bottom pieces which will ultimately enclose the glass roast chamber) and I am just about ready to start building the roaster -but I am wondering the best way to 'seal' the glass RC within the funnel. The first funnel I bought was a little too small (see pics), so I have ordered another that is 4.25" diameter. My RC is 4" diameter so this should give me room for a 1/8" thick gasket of sorts. Due to the design of my roaster, I need to be able to remove the glass chamber for cleaning, so a permanent seal isn't ideal and would require some design changes. I had an idea of using something like a bbq gasket (https://www.amazo...NrPXRydWU=) around the inner diameter of the funnel so the glass RC will fit snug up against it when inserted. Does anyone see any issues with this? Will there be a problem with thermal expansion if a non-rubberized gasket is used? And will the adhesive on this bbq gasket hold up to the temps? Any help on the matter is greatly appreciated.

Also attached a pic of the rough design - duct tape connections to assess space within the enclosure lol
cdrake39 attached the following images:
rc2_resized.jpg cad_mockup.jpg
Edited by cdrake39 on 01/20/2020 2:17 PM
 
greencardigan
Top  #14 Print Post
Posted on 01/20/2020 3:51 PM
On my small roaster, I just have the glass sitting inside the funnel without any gasket or seal. It's held in place by the upper roast chamber but is free to move a little bit.

My larger roaster has a small bead of RTV silicon on the base of the glass tube. So there's essentially a gasket between the base of the tube and the funnel but again, it's just sitting in the funnel not attached.
 
CharcoalRoaster
Top  #15 Print Post
Posted on 01/20/2020 6:37 PM
Nice compact design! I dig it. What's the capacity?
 
cdrake39
Top  #16 Print Post
Posted on 01/20/2020 7:38 PM

Quote

greencardigan wrote:

On my small roaster, I just have the glass sitting inside the funnel without any gasket or seal. It's held in place by the upper roast chamber but is free to move a little bit.

My larger roaster has a small bead of RTV silicon on the base of the glass tube. So there's essentially a gasket between the base of the tube and the funnel but again, it's just sitting in the funnel not attached.


Ok, good to know! I wasn't sure how important the seal between the glass and funnel would need to be in terms of air flow. I may design a custom gasket mold (3d print) and cast a gasket with RTV silicon. I guess to 400F stuff works just fine?

Edit: Found this food safe RTV silicone good to 500F. Should do the trick?
https://www.amazo...&psc=1
Edited by cdrake39 on 01/20/2020 8:30 PM
 
cdrake39
Top  #17 Print Post
Posted on 01/20/2020 7:40 PM

Quote

CharcoalRoaster wrote:

Nice compact design! I dig it. What's the capacity?


Thanks! That was the goal from the beginning, something 'counter top' size. The blower motor can loft 350g+ but I'm thinking my limiting factor will be the heating element. I may entertain the idea of dual in-line elements down the road if I ever want to increase the capacity. I'm hoping to do 250g batches with this current design.
 
CK
Top  #18 Print Post
Posted on 01/20/2020 9:17 PM

Quote

cdrake39 wrote:

Ok, good to know! I wasn't sure how important the seal between the glass and funnel would need to be in terms of air flow. I may design a custom gasket mold (3d print) and cast a gasket with RTV silicon. I guess to 400F stuff works just fine?

Edit: Found this food safe RTV silicone good to 500F. Should do the trick?
https://www.amazo...&psc=1


Good silicone to use. Here's a link to a technique that works well.

https://www.instr...nd-tubing/
 
cdrake39
Top  #19 Print Post
Posted on 01/20/2020 10:39 PM

Quote

CK wrote:

Quote

cdrake39 wrote:

Ok, good to know! I wasn't sure how important the seal between the glass and funnel would need to be in terms of air flow. I may design a custom gasket mold (3d print) and cast a gasket with RTV silicon. I guess to 400F stuff works just fine?

Edit: Found this food safe RTV silicone good to 500F. Should do the trick?
https://www.amazo...&psc=1


Good silicone to use. Here's a link to a technique that works well.

https://www.instr...nd-tubing/


Very cool technique! Thanks for the tip
 
CharcoalRoaster
Top  #20 Print Post
Posted on 01/21/2020 8:17 AM

Quote

CK wrote:

Quote

cdrake39 wrote:

Ok, good to know! I wasn't sure how important the seal between the glass and funnel would need to be in terms of air flow. I may design a custom gasket mold (3d print) and cast a gasket with RTV silicon. I guess to 400F stuff works just fine?

Edit: Found this food safe RTV silicone good to 500F. Should do the trick?
https://www.amazo...&psc=1


Good silicone to use. Here's a link to a technique that works well.

https://www.instr...nd-tubing/


Now that's dope cool
 
jbrux4
Top  #21 Print Post
Posted on 01/21/2020 8:55 AM

Quote

CK wrote:

Good silicone to use. Here's a link to a technique that works well.

https://www.instr...nd-tubing/


Thanks for this great find. It will come in very handy in many situations.
R/
Jared
 
snwcmpr
Top  #22 Print Post
Posted on 01/26/2020 3:36 PM
I found this high temp sealer.
https://www.amazo...G69RC?th=1
Up to 600 degrees.
Edited by snwcmpr on 01/28/2020 12:05 PM
--------------
Backwoods Roaster
"I wish I could taste as well as I wish I could roast."

As Abraham Lincoln said "Do not trust everything you read on the internet".
 
cdrake39
Top  #23 Print Post
Posted on 02/02/2020 11:20 PM
Well, after some contemplation (and convincing from another user - thanks jbrux4!) I decided to use tri clamp fittings in my design. The primary reasons for this change are ease of cleaning, modular setup which allows for easier upgrades in the future, and aesthetics. The photo shows the concept for this design. Lots of design details to work out, but I'll have a better idea of how to tackle them when the parts arrive. I'm hoping to permanently affix a mesh gasket to the bottom of the 4" sight glass so I can remove that section (without having beans fall everywhere) to remove the beans when roasted.
cdrake39 attached the following image:
20200202_214616.png
 
renatoa
Top  #24 Print Post
Posted on 02/03/2020 1:09 AM
Is there any reason to lower the level of cyclone so much ?

Is the heater in the picture, or outside the box ?
 
cdrake39
Top  #25 Print Post
Posted on 02/03/2020 8:31 AM

Quote

renatoa wrote:

Is there any reason to lower the level of cyclone so much ?

Is the heater in the picture, or outside the box ?


No reason at all. Do you see any disadvantages with this design? It may be too late for me to change anything on this design, but I'm open to ideas for improvements!

The heating element will be in the straight section of piping just below the roast chamber.
 
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