topbanner.gif
Login
Username

Password




Not a member yet?
Click here to register.

Forgotten your password?
Request a new one here.
Shoutbox
You must login to post a message.

renatoa
08/13/2022 1:06 AM
Welcome, @tombull !

renatoa
08/10/2022 1:56 AM
nguyencoffeesupply
and RoyB, Welcome

renatoa
08/06/2022 1:31 PM
Welcome, oak202, CoffeeNutZ and Mlcharlestonsc

Strangeworth
08/04/2022 9:34 PM
Thank you!

renatoa
08/03/2022 2:09 AM
Strangeworth and BigPalm, welcome to forum

In Memory Of Ginny
Donations

Latest Donations
dmccallum - 10.00
JackH - 25.00
snwcmpr - 10.00
Anonymous - 2.00
Anonymous - 5.00
Users Online
Guests Online: 6

Members Online: 0

Total Members: 7,628
Newest Member: tombull

View Thread

Who is here? 1 guest(s)
 Print Thread
Air, Drum or other roaster?
jm82792
I've hit the point at time where I am getting rather tired of pan roasting.
It works but smoke in the house, chaff and inconsistencies are getting old.
I like the idea of using a drum, however using hot air to keep the beans constantly in movement sounds nice too(seems like you can go really small with it).
I would like to have a design that's simple, controllable(I want to hookup a spare arduino I have, so I'd like to easily utilize a PID), small (250 gram minimum batch size? or something somewhere near it), and finally efficient since electricity is horrifically expensive out here.
(a toaster oven mod seems bad in efficiency.)
For drum roasters I've seen open gas flame,
an oven configuration, the drum can have holes, the drum doesn't have much in the way of holes......

So what design, example or model do you suggest that I should build ?
I've read through the forums and it seems like there are a variety of ways to go about doing it.
Edited by jm82792 on 01/29/2011 2:47 AM
 
seedlings
For you, I suggest propane, and the simplest design is RoasterRob's:

http://forum.home...ad_id=1709

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
jm82792
Hmm the biggest issue I see is that I can't weld and it seems to be a very nice thing to have for that kind of design.
Are drum based roasters utilizing propane a bad idea?
 
allenb
If you decide on a drum roaster I would highly recommend looking at Dan's design.

http://forum.home...post_21402

Can handle 1 lb, very robust design, simple to operate.

I would also highly recommend staying with electric resistive heat if it will be your first drum build unless you've already got some combustion design experience under your belt. Other's here at HRO have built some nice gas fired drum roasters but have had to log many hours of trial and error with burner configuration. Also, making small, repeatable power level adjustments is much less of an issue with electric versus gas. On the issue of gas being more economical than electric, unless you will be using the roaster in a production environment it should not end up costing much per month using one or the other.

If you end up going with a fluidbed, I agree you should look at RoasterRob's excellent design.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
randytsuch
Small and PIDable does not seem like gas to me.

I guess you can do it, but putting a PID on a gas setup seems hard to me (maybe because I have not used a gas roaster before)

PID implies either a DIY rig, like a modded popcorn popper, turbo crazy or something similar to me.

You could also buy a small drum, and modify it. I have an older alpenrost that has been gutted, and modded to run off of PID

Randy
 
allenb

Quote

randytsuch wrote:
Small and PIDable does not seem like gas to me.

I guess you can do it, but putting a PID on a gas setup seems hard to me (maybe because I have not used a gas roaster before)

PID implies either a DIY rig, like a modded popcorn popper, turbo crazy or something similar to me.

You could also buy a small drum, and modify it. I have an older alpenrost that has been gutted, and modded to run off of PID

Randy


Valid point. Rigging a gas roaster for PID is definitely a challenge with the need of a motorized, servo driven gas valve as well as the issue of maintaining proper combustion air mix over it's throttling range. I've read somewhere in the past where someone designed a gas burner system that maintained a constant burn rate and the environment temp was controlled via a simple RC servo motor attached to a bypass damper. The damper would vary how much heat passed through the roasting path versus out through a separate opening to atmosphere.

The PID controller sent a variable pulse width modulated output to the RC servo.

To PID Dan's roaster would require a probe entering through the barrel front opening for sensing bean temp which could be a challenge.

I also agree that modding a Alpen or Hottop if one could find one on the cheap would save a lot of major design and build time.

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

Quote

allenb wrote:
a motorized, servo driven gas valve as well.

Anywhere you could point to read more about this type of valve?applications?

sean
Sean Harrington
educate.
 
allenb

Quote

Unta wrote:

Quote

allenb wrote:
a motorized, servo driven gas valve as well.

Anywhere you could point to read more about this type of valve?applications?

sean


Here's some examples. Some are PWM controlled and many are able to be controlled by 0-10 DC and 4-20 ma from a standard PID controller.

Unfortunately, They are pretty pricey but I'm sure there are more generic low cost options out there if someone were to scour the internet.

http://www.aalbor...verview/27

http://www.ascova...flowR3.pdf

http://www.hassmf...mit=Search

http://www.equili...PA/QB1.pdf
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
allenb
There's another option for drum roasters that Carl Staub incorporated on his roasters a few years back called "pulse firing" which is actually a better option in my opinion since you don't have to worry about fuel/air mix going out of whack. This method also has the advantage of only needing simple on/off solenoids instead of proportional gas valves with steep $ tags. You also have to incorporate a standing pilot for instant on/off of burners.

I need to retract the statement on needing a standing pilot for instant on/off. Now I'm not sure how Carl set up ignition of the burners. Maybe it was electronic spark ignition but I remember when the burners came on it was immediate. His burner arrangement was a long pipe with multiple brass jets aiming up toward the drum which you would think to achieve instant ignition you would need a spark igniter at each jet.

Here's an article covering the technology:

http://www.frahme...epaper.htm
Edited by allenb on 01/30/2011 2:39 PM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
jm82792
Slight information overload Grin
PID as I know with my limited knowledge is a temperature probe that reads the bean temperature and physically touches them during the roast.
So what you are saying is that PID for a small drum roaster isn't easy because getting the sensor there isn't easy.

For gas I understand your point and from what I'm being told it's not easy, PID and/or gas for a small roaster without lots of trial and error.

Modulating the temperature automatically with temperature probe information could be done by pulsing the gas flow with and have electronic ignition(easy to do from my former HV hobby experience).

But I am more into simplicity and it seems that gas isn't practical for my application.


So basically it tosses me to a drum roaster or fluidized air.
Economics regarding the heating source isn't a big deal I guess.
Electricity is around 5X more than the mainland($.45 a kilowatt) but even 2 hours with a 2 kilowatt load would only cost me $1.80. My aquarium uses around 30 times that in a month :)


For the heating coils can they be turned on and off
(during a roast to keep the temperature constant),
or will thermally cycling them cause an issue?
(I see a few people using variacs and that's why I'm curious)

I don't see how it's completely done with Dan's design,
but I really like the design and it's simplicity.






 
Unta

Quote

allenb wrote:
There's another option for drum roasters that Carl Staub incorporated on his roasters a few years back called "pulse firing" which is actually a better option in my opinion since you don't have to worry about fuel/air mix going out of whack. This method also has the advantage of only needing simple on/off solenoids instead of proportional gas valves with steep $ tags. You also have to incorporate a standing pilot for instant on/off of burners.

I need to retract the statement on needing a standing pilot for instant on/off. Now I'm not sure how Carl set up ignition of the burners. Maybe it was electronic spark ignition but I remember when the burners came on it was immediate. His burner arrangement was a long pipe with multiple brass jets aiming up toward the drum which you would think to achieve instant ignition you would need a spark igniter at each jet.

Here's an article covering the technology:

http://www.frahme...epaper.htm


Thanks Allen.
sean
Sean Harrington
educate.
 
jm82792
Is there any insulation utilized for Dan's roaster?
It seems like it but the low resolution pictures make it difficult to discern.
For the drum, should I do a mesh drum or a solid drums with vent holes for smoke?
Overall this design seems easy, I'll be doing a good amount of thread tapping and maybe if i get lucky I can utilize a welder from a friend.

 
Dan
You can't see it in the photos, but I'm using 1/4" of ceramic felt insultaion and an aluminum flashing liner to protect the felt. At the end of the roast the machine is hot, but doesn't burn.

My machine has been PIDed for many years. The TC is mounted vertically alongside the drum, about 1/2" away. This system does a great job of controlling the heat around the drum. You can see the probe in this image.

www.claycritters.com/coffee/bollinger%20sample%20roaster2.jpg

PS: If you click on the thumbnails you'll get a larger image.
Edited by Dan on 01/31/2011 6:34 AM
 
jm82792
What metal did you use for the sheeting?
Approximately what are the rough dimensions of the roaster(roast chamber, drum, etc)?
Is the drum solid or does it have holes?
Thanks :)
 
Dan
This is all from memory, so beware! The chassis is about 18ga galvanized, MIG welded. The liner is aluminum flashing, so thin you can cut if with scissors.

The drum is 7" x 7" with the ends solid and wall perforated. the front end is funnel shaped to help when dumping beans. The tilting roasting chamber is about 9" x 9" x 9" with the heater box and control box both being 9" x 9" x 3".

This picture shows how it looked when new. Since then I've removed the useless top vent and the dial thermometer, and added a PID.

www.claycritters.com/coffee/bollinger%20sample%20roaster4.jpg

Let's face it. What every home roaster wants is a sample roaster!
Edited by Dan on 02/02/2011 7:21 AM
 
jm82792
Thank you for the dimensions !
Is aluminum sheeting a bad idea for the body?
I've been looking at some .125'' 12'' X 12'' sheets for the roaster chamber, combined with some square aluminum tube and angle for the body.
I've tapped aluminum heatsinks and angle before. I feel confident enough tapping aluminum.. It's cheaper then stainless($36 for a 12''x12'' sheet) plus I won't have to deal with galvanized steel rusting (from scratched coating) due to 90% humidity. Plus from what I hear stainless is a pain to tap.

I've seen a lot of perforated aluminum for sale,
I might be able to fabricate a drum with it....






 
Jump to Forum:

Similar Threads

Thread Forum Replies Last Post
My 1-2 KG drum roaster Drum Roasters 8 08/09/2022 11:57 PM
My U.A.F. hot air roaster (Dedicated to renatoa) Fluidbed Roaster 4 07/22/2022 3:03 PM
Hottop Modded Drum? HotTop Roaster 1 07/12/2022 1:21 PM
1-6 lbs Roaster Build - Nothing Fancy Drum Roasters 26 06/21/2022 3:52 AM
Waiting on my Roaster and beans. Roasting Coffee 4 06/21/2022 3:44 AM
Homeroasters Association Logo, and all Content, Images, and Icons © 2005-2016 Homeroasters Association - Logos are the property of their respective owners.
Powered by PHP-Fusion Copyright © 2022 PHP-Fusion Inc
Released as free software without warranties under GNU Affero GPL v3
Designed with by NetriX