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10/19/2021 6:22 AM
Welcome tarunk!

10/17/2021 12:40 PM
Ploni and nader fouad, Welcome!

10/15/2021 2:19 AM
merlot85, maycondelpiero and hoeltz, Welcome !

10/14/2021 10:06 AM
Thanks for the addition to the group. Seriously considering building a drum roaster along the lines of oldgrumpus's. Love the design and craftsmanship.

10/14/2021 4:00 AM
Morning, ar3mia ! and... coffee drink

In Memory Of Ginny
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1lb Fluidbed Roaster Build
seedlings
Yep. You want those in series to a 220V source - that's what I did. For the circulation, you need to have about 20% of the surface area perforated, give or take.
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
ChicagoJohn

Quote

oldgearhead wrote:

JSA Coffee has called attention to the problems with electric heat. If you want to run two 120 volt 1800 watt heaters you must go with a 220 volt service.


From your experience, OGH, what would you estimate a maximum load might be under ideal fluidizing conditions for an 1800 watt heat source without recirculation? I have one finished waiting to test and want to try it with a close approximation to a maximum level. I was hoping for maybe 400 gm greens.
So many beans; so little time....
oldgearhead
I can only roast 350 grams with my 1550 watt heater with no re-claiming (top open) in 60?F air.
With the hood closed I can roast 500 grams with 1200 watts in 35?F ambient. Re-claiming hot air from the RC is not an add on it's an important part of the design,. I also have a door on the 'box' that allows me to roast 420 grams in 11?F . My percent on time at 420 grams (will fit in a one quart Mason jar) is 95-ambient in ?C, and for 500 grams its 100-ambient in ?C..I usually roast one quart (420 grams) batches because its less trouble with the jars..
No oil on my beans...
greencardigan
My small air roaster is capable of around 350g. I can't recall if my heatgun element is 1800W or 2000W. My circulation is fairly good (not too energetic but good circulation) and my ambient temps are usually around 20 degrees Celcius.

I sometimes hit a point a few minutes before FC where my heater maxes out at 100% and turning down the airflow any more stops bean circulation. However, once i get through that portion of the roast profile, my heater output usually sits at around 85-90%.

Based on my experience I think you might just get 400g if you had ideal airflow/circulation and reasonable ambient temperatures.
BenKeith
I don't reclaim air. I'm running an iRoast2 heater/blower with a 2,400 watt heating element I made and replaced the 1,500 watt one in it.
We are not huge coffee drinkers so I typically only roast 200 grams per roast because I like to roast in five day to one week cycles, and generally do at least two different beans. So, that's about all we use in that time. I'm sure I could easily roast 300+ grams if needed, but have never had a need to do that.

I normally never see 100% on my heater but this past week, after modifying the roast chamber and increasing the input another 5/8" to improve bean movement. I'm finding if the temps in the garage are below about 45 degrees F, when I get to 400F I have to reduce my blower to 75% to take the beans to SC and keep the heat from staying on 100%. However even at 75%, I'm still getting plenty of bean movement at those temps. In fact, in higher summer time temps, I've always had to reduce the fan to keep from getting too much circulation and my heat's hanging around 50% them.
Now, I will just try to avoid roasting when I'm freezing my butt off doing it.
ChicagoJohn

Quote

oldgearhead wrote:

I can only roast 350 grams with my 1550 watt heater with no re-claiming (top open) in 60?F air.


Thanks for the information. I'd be OK with 350 gm and will start with that. My design has a 4A vacuum cleaner brushed motor (on PWM) that is in-line so I don't currently have the option of directing very hot air back the intake -- also my housing is PVC with only the portion after the heater using aluminized fiberglass heat shield (whether that will work without deformation / melting remains to be seen). Maybe a venturi effect hot air addition could be made to work but I'll save that for later. Your heat recirculation idea makes a lot of sense and had I thought of it, I'd likely have selected different materials but it is what it is for now. I'm using a popcorn heater assembly with parallel coils at 9 ohms yielding close to 1.8 kW with our 125VAC supply. We should have weather over 40 here Sun and Mon, so I'll get my chance.

Thanks for all that excellent info ! I'm using a popcorn heater assembly with parallel coils at 9 ohms yielding close to 1.8 kW with our 125VAC supply. We should have weather over 40 here Sun and Mon, so I'll get my chance.
So many beans; so little time....
ChicagoJohn

Quote

greencardigan wrote:

My small air roaster is capable of around 350g. I can't recall if my heatgun element is 1800W or 2000W. My circulation is fairly good (not too energetic but good circulation) and my ambient temps are usually around 20 degrees Celcius.

I sometimes hit a point a few minutes before FC where my heater maxes out at 100% and turning down the airflow any more stops bean circulation. However, once i get through that portion of the roast profile, my heater output usually sits at around 85-90%.

Based on my experience I think you might just get 400g if you had ideal airflow/circulation and reasonable ambient temperatures.


Thanks for sharing your experience. I'll be happy if I can use 350 gm and you and OGH's comments support that as a possibility. We'll see. I like the popcorn popper assembly because to me the geometry of the housing suggests someone did some good design engineering to maximize efficiency of heat transfer. I've been doing 91 gm all along in my popper, so if I can do X4 that, great. I'll be using the same automation of stepper motor on the heat PWM that I developed for the popper and that logs time-temperature in addition to controlling it so we'll see what happens smoking
So many beans; so little time....
ChicagoJohn

Quote

BenKeith wrote:

I don't reclaim air. I'm running an iRoast2 heater/blower with a 2,400 watt heating element I made and replaced the 1,500 watt one in it.
We are not huge coffee drinkers so I typically only roast 200 grams per roast because I like to roast in five day to one week cycles, and generally do at least two different beans. So, that's about all we use in that time. I'm sure I could easily roast 300+ grams if needed, but have never had a need to do that.

I normally never see 100% on my heater but this past week, after modifying the roast chamber and increasing the input another 5/8" to improve bean movement. I'm finding if the temps in the garage are below about 45 degrees F, when I get to 400F I have to reduce my blower to 75% to take the beans to SC and keep the heat from staying on 100%. However even at 75%, I'm still getting plenty of bean movement at those temps. In fact, in higher summer time temps, I've always had to reduce the fan to keep from getting too much circulation and my heat's hanging around 50% them.
Now, I will just try to avoid roasting when I'm freezing my butt off doing it.


Thanks for sharing your experience. I'm with you on the effect of cold ambient air ... more of issue for me, maybe, but it definitely affects the roast as well. I think your results are encouraging relative to maybe a 300 - 350 gm batch size, but we'll see I guess Grin
So many beans; so little time....
oldgearhead

Quote

ChicagoJohn wrote:

Quote

oldgearhead wrote:

I can only roast 350 grams with my 1550 watt heater with no re-claiming (top open) in 60?F air.


Thanks for the information. I'd be OK with 350 gm and will start with that. My design has a 4A vacuum cleaner brushed motor (on PWM) that is in-line so I don't currently have the option of directing very hot air back the intake -- also my housing is PVC with only the portion after the heater using aluminized fiberglass heat shield (whether that will work without deformation / melting remains to be seen).,<snip>

I have 125F - 1500F above the RC. The inlet pipe is PVC and the 'box' is stainless steel. The rather standard flow-through, two-stage, in-line vac motor has been living on the re-claimed air for over six years now, and it was used, in a boot, for a spa blower before I got it. The vac blower can take it. I wouldn't run the PVC over 170?F though..A typical roast runs 55 CFM to 40 CFM. I keep the beans moving very slowly..
Edited by oldgearhead on 12/21/2016 7:47 PM
No oil on my beans...
ChicagoJohn

Quote


I have 125F - 1500F above the RC. The inlet pipe is PVC and the 'box' is stainless steel. The rather standard flow-through, two-stage, in-line vac motor has been living on the re-claimed air for over six years now, and it was used, in a boot, for a spa blower before I got it. The vac blower can take it. I wouldn't run the PVC over 170?F though..A typical roast runs 55 CFM to 40 CFM. I keep the beans moving very slowly..


I really appreciate this info, OGH. The blower I have is from an Oreck XL I found at Goodwill for $3.99. I have it in its boot also. First time I fired it up it blew the heater assembly up about 2 feet in the air and it was only at about 1/4 power so I know it'll be more than sufficient. I have an anemometer and will measure cfm to apply your data.

Your info on recirc is very encouraging and I'll definitely factor that in now going forward. Do you happen to have any data on the temperature of the hot air at the inlet to the motor and is there some ambient air that gets mixed with it or is everything going into the motor recirc air?
So many beans; so little time....
oldgearhead

Quote

ChicagoJohn wrote:

Quote


I have 125F - 1500F above the RC. The inlet pipe is PVC and the 'box' is stainless steel. The rather standard flow-through, two-stage, in-line vac motor has been living on the re-claimed air for over six years now, and it was used, in a boot, for a spa blower before I got it. The vac blower can take it. I wouldn't run the PVC over 170?F though..A typical roast runs 55 CFM to 40 CFM. I keep the beans moving very slowly..


I really appreciate this info, OGH. The blower I have is from an Oreck XL I found at Goodwill for $3.99. I have it in its boot also. First time I fired it up it blew the heater assembly up about 2 feet in the air and it was only at about 1/4 power so I know it'll be more than sufficient. I have an anemometer and will measure cfm to apply your data.

Your info on recirc is very encouraging and I'll definitely factor that in now going forward. Do you happen to have any data on the temperature of the hot air at the inlet to the motor and is there some ambient air that gets mixed with it or is everything going into the motor recirc air?

The inlet runs 125?F to 150?F (depends on the ambient air temperature). The 'mixing box' does bring in ambient air that joins up with the hot air from the RC. In very cold weather, I have roasted in 11?F ambient but it was nor fun. There is a 'door' on the mixing box that I can close in cold weather taht limits the amount of ambient air that enters the box. The complete build is here:
http://forum.home...ad_id=2207
No oil on my beans...
oldgearhead
The other things that's unique is the RC's output is restricted and cooling is done in the RC..
No oil on my beans...
CharcoalRoaster
I'm glad this thread has turned into a helpful place for others to work out the kinks of their FB builds. I tore down and rebuilt my whole setup as described in the OP. I was losing too much heat (I think) through the various connections between heatin elements, blower, and RC. I think I've come up with a better design to allow more efficient use of space, heat, and energy. I've run a test load and have even better bean circulation. the question will be whether or not I've got the design efficient enough to heat the beans to roast temps. I've attached a drawing of what the new setup is.

My new question is where the heck do I find another rubber spa blower/vac motor boot with an inlet/outlet? I've searched all over eBay and Google can't even help me find one!

https://www.dropb...r.jpg?dl=0
ChicagoJohn

Quote

CharcoalRoaster wrote:

I'm glad this thread has turned into a helpful place for others to work out the kinks of their FB builds. I tore down and rebuilt my whole setup as described in the OP. I was losing too much heat (I think) through the various connections between heatin elements, blower, and RC. I think I've come up with a better design to allow more efficient use of space, heat, and energy. I've run a test load and have even better bean circulation. the question will be whether or not I've got the design efficient enough to heat the beans to roast temps. I've attached a drawing of what the new setup is.

My new question is where the heck do I find another rubber spa blower/vac motor boot with an inlet/outlet? I've searched all over eBay and Google can't even help me find one!

https://www.dropb...r.jpg?dl=0


Unless I'm not looking at it right, in your drawing it looks like the rubber boot will be exposed to high heat. Is the boot made of high-temperature silicone elastomer or similar material that can withstand that? Also, what is the diameter of the blower and boot where it attaches to the motor?
So many beans; so little time....
oldgearhead
Not so in mine. Inlet air only. I sold the last one I was able to find. The boot is from a Sundance spa and they have change designed and don't use a vac motor anymore. You have to keep watch on eBay for them. Mine has seen 125?F - 150?F air for six years. One more thing I should mention is heat build-up in an inline vac motor. I have that under control with four quarter inch holes in the manifold between the motor and the heater, This keeps the RPM higher on the motor for better cooling.
No oil on my beans...
ChicagoJohn

Quote

oldgearhead wrote:

Not so in mine. Inlet air only. I sold the last one I was able to find. The boot is from a Sundance spa and they have change designed and don't use a vac motor anymore. You have to keep watch on eBay for them. Mine has seen 125?F - 150?F air for six years. One more thing I should mention is heat build-up in an inline vac motor. I have that under control with four quarter inch holes in the manifold between the motor and the heater, This keeps the RPM higher on the motor for better cooling.


Looking at CharcoalRoaster's diagram, however, unless I'm missing something, it seems that the boot would be directly exposed to the roasting heat source -- radiant as well as convection. Other than some silicones and fluoropolymers, I don't know of any elastomers that would hold up to temperatures in the 420F range where you will get degradation of most organic compounds. I would think you'd need metal or at least a high temperature phenolic or fluoropolymer, but maybe I'm not understanding the drawing.
So many beans; so little time....
CharcoalRoaster
No John, you're correct. I thought it was the same black rubber material as some stove pipe connections I've used under high heat in the past...

Good to know though about heat build up. I may go ahead and drill a few holes like you suggest OGH.

The boot itself is the one I purchased from OGH a while back. I'm sort of stuck on how to reduce the transition from the chamber where air+heat mix into my RC. The boot fit a little too perfectly.

You know what they say... If it's too good to be true, it must not be true Shock
oldgearhead
I used twp inch PVC at the inlet and 1.77 steel sink drain on the outlet
(I think), with one boot.
No oil on my beans...
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