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snwcmpr
03/20/2019 4:17 AM
Eth Yirg Nat Idido Gr1 today.

snwcmpr
03/18/2019 8:15 AM
1 lb roasted lasts a week. I can taste the flavor increase to peak, then drop after. Still very good, but interesting to follow the wave of flavor rise and fall.

snwcmpr
03/11/2019 4:10 PM
Roasted Panama Gesha Esmeralda yesterday. Yummy.

Beebee74
03/11/2019 3:10 PM
I seem to have lost any roasting touch I thought I had. Very frustrated to be wasting time and money. I’m hoping someone can provide some insight on roasting at high altitude. I’m at 4400ft. Thank

aicardo
03/07/2019 8:50 AM
tb

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coffeeroastersclub's up to 2 lb. capacity Fluid Bed roaster
coffeeroastersclub
My wife and I just got done building an up to 2 lb. electric fluid bed roaster for our own use. I thought I would post a video of the trials and tribulations of building one from scratch. The build took about a month of spare time and went through about 4 major modifications until I was satisfied as to its performance.

I want to give a mention of appreciation to Jim (Oldgearhead) for some great input he provided during the process. I initially intended to implement a heat reclamation process to increase the roasters efficiency and since he uses such I reached out and asked for some advice for my design. Ultimately I had to change my design and not use the reclamation device for my roaster but nonetheless his input was very much appreciated.

The video is long, over an hour and a half and a bit redundant in areas as it is a splicing of about 8 or so takes over a period of about 3 weeks. It shows some good info on the fluid bed process I use, PID functions, cool down functions, etc. There is even a light show when an element blows up. The end segment shows an entire roast from the very start to the finish.

I do not intend to patent anything regarding the roaster. It is only for our personal use. Feel free to ask questions, leave comments. Here it is:

[video]https://www.youtube.com/watch?feature=player_detailpage&v=e_J8nctWTBY[/video]

==========
Len
Edited by ginny on 04/18/2015 10:28 AM
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
JETROASTER
Hi Len,
What turned out to be the most challenging part?
Cheers, Scott
 
coffeeroastersclub
Hello Scott. Getting the heating elements so they would not constantly blow was most challenging. I initially used 3 heating gun elements (I puchased 3 Pit Bull heat guns from amazon
http://www.amazon...s=heat+gun )
and took the elements and element holders out of each. They would blow. I then purchased 3 Master Appliance elements from ebay:
http://www.ebay.c...EBIDX%3AIT

Not much better, they would blow too. I ended up taking off the burnt coil from each Master Appliance element and replacing that coil with Kanthal coil I picked up from amazon:
http://www.amazon...&psc=1

That did the trick. I also found a setting in my PID (OUTH) where I can set the percentage of wattage going to the coils. Instead of 100% power going to the elements at all times they are on I keep it in a range of 50 to 75%.

I also had an issue with the SSRs I was using with the PID. I was using two 40amp SSRs, one for one of the coils and one for the remaining 2. The one that was used with the 2 coils kept failing by sticking in the closed position. I ended up using a separate SSR for each coil using the same input signal from the PID.

So now it will do a 5 minute dry to 300 degrees F bean mass, and then 6 minutes more to 426 for a City+ roast. That is with 1 pound 10 oz. of beans with OUTH at a 60% average. Ultimately I want to put an extension on the roast chamber to do a 5 pound roast. I believe the unit will handle it, we'll see.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
JETROASTER
What was causing the blow-outs?
-Scott
 
coffeeroastersclub
The original heat gun and Master Appliance coils are spaced pretty close together on their ceramic holding post and at the very bottom of the coil the coils would warp and blow which kept confounding me because they were the only 3 air inlets for the roaster. After going through about 9 coils I decided to take the burnt coils off their holding posts and wrap with Kanthal coil. I stretched the Kanthal coil so that the loops were a little bit farther apart than the Masters, and that with the tuning of the OUTH output of the PID did the trick.

If the Masters Coils are nichrome that could have been a factor as to why they would blow and the Kanthal wire not.

However a problem with the above is that I was not aware of the OUTH setting of the PID until after I wound the Kanthal on the posts, so I do not know if that would have helped in the original setup. One of those things; you can read a PID manual a hundred times and still find new things to help.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
What I noticed:
1) For the first 40 minutes or so of the video, the bean flow was very low,
indicating lack of air-flow for cooling the elements as well. Also when the two 'bypass-cooling gates were opened cooling air for the elements was further reduced.
2) The last 30 minutes ro so of the video indicated that the flow (CFM) problem was corrected and you even had control of the blower speed.
3) What really puzzles me is why the blower speed isn't being reduced as the beans become lighter. In my fluid-bed roaster and my old Zach & Dani (not exactly a fluid-bed), the blower speed is inversely proportional to the bean temperature.
4)When dealing with a vacuum it is probably difficult to end up with equal air-flow (cfm) at each element intake. Did you measure cfm?
Also, why three elements/ Didn't that make it harder to balance the air-flow? Wouldn't two elements be easier to deal with? Or maybe four elements, two in series on each side?

btw - Great study project!
Edited by JackH on 04/18/2015 12:16 PM
 
coffeeroastersclub
Hello Jim. The first roast you see that I did on the video was actually my second roast using the heat exchanger. The low bean flow was caused by the 1/4" diameter copper pipes becoming unsealed from the canisters air chambers, causing a suction leak. The tiny tubes also got partially clogged with tiny bits of chaff that my separator did not stop. I was able to correct the separator issue but as you know I gave up on the heat extractor.

I had tried 2 elements at first but found that the roaster would not keep up with what the PID wanted for temp at a given time. I look for 11 minute 436F bean mass and 2with 2 elements it just wouldnt keep up. With the 3 it does.

I put in the variable rate control just prior to my last roast. I have a bit of experimenting to do with that function. The reason I put it there was because I had done a very dark roast (intentionally), an Italian Espresso Roast, and the beans got shattered caused by higher than needed CFM and the design of my suction based roast chamber. I have some fiddling around to do with that switch. As you mention I should lower fan speed toward the end of the roast; I was a bit anxious about blowing the new coils so I kept it running high.

The air balance appears to be ok; air just come in through the top of the 3 elements and then up through the bottom of the roast chamber and into the beans. All elements work off the same signal output of the PID, each with its own SSR. I do not use autotune on it, just on/off.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
Len,
From the video it appeared to me he heating element blew when the the flow rate was very low.In addition to that I thought about my own Master Appliance HAS-043K heat gun element that has over 263 hours at an average duty cycle of 74% (7.4 seconds on time per cycle). The big difference is that mine has always seen 110°F inlet air at 2.5-3.5 meters/second. All the air must pass through a 3 inch diameter pipe. Therefore, the average flow rate during heating is 30 CFM. Because the bean mass is no longer fluid below 20 CFM, the heating element never sees less 20 CFM.
Except the one time I messed up and burned the beans.

Summary, My thinking is by using 3 elements and splitting the available air into 3 paths each element is receiving much less air than mine during a typical 500 gram roast. However, we can't know that unless you measure the velocities. On the other hand my inlet air is much warmer and my bed moves much slower so that may not be the cause of you element failures.

Congrats on a great project.
 
coffeeroastersclub
Jim,

My air inlet tubes are about 1 1/4" diameter each. I don't have a tool to measure the inlet CFM. I have wondered if I knew about the OUTH setting on my PID in the very beginning and set it at 75% if that would have prevented all the coil burnups. I am going to add an extension onto the roast chamber to hopefully up the roast capacity to 5 pounds green. I may have to up the OUTH to higher than 75%. It will be a good test of the new Kanthal wire I wound on the coil posts.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
OOps! Correction:
The velocities I have recorded during heating range from 3.2 to 5.5 meters/second. Sorry i read the wrong line. Therefore, from the flow rate calculator for a 3 inch pipe, the cubic feet per hour range is 31 to 53.
 
coffeeroastersclub
Well I did 5 pounds green in the roaster this evening. I added an extension to the interior and exterior cylinders to enable it to do so. I had some issues to reckon with; controlling the ramp to 435 degrees F bean mass was difficult and slower than expected. I initially started the roast at 75% output on the heating elements and ended with 100%. The mass collapsed at the end during cooling and I ended up with a mix of city+ and vienna due to the cool down issue caused by the collapsed fluid bed mass. I believe the issues were due not to suction leakage but the perforated interior cylinder extension I added on. Going to fix that and do another test. Going through alot of beans, LOL, the freezer is full.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
I'm pretty sure any heat gun element will burn out if the air flow drops below a certain rate while at a certain wattage. I suspect every heat gun engineer knows what that number is. All I know is:
1) I ran mine at 1100 watts for 20 seconds at 0.0 m/sec and burned several beans, but the element was still alive.
2) My flow rate is rarely less than 4 m/sec.
3) Anemometers aren't very expensive.
 
coffeeroastersclub
I'm going to get an anemometer. Do you think the following one is decent enough to do the job?

http://www.amazon...nemometers

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
coffeeroastersclub
I have a bunch of ceramic terminals that I am going to use to create a few kanthal wire heaters with to replace the heat gun coils. They have been hanging around for a few years so I will put them to use. Maybe the setup will be easier to deal with.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
coffeeroastersclub wrote:

I'm going to get an anemometer. Do you think the following one is decent enough to do the job?

http://www.amazon...nemometers

Len


That looks like the one I use the most..
 
coffeeroastersclub
I now have an updated video of the roaster which now has a 5 lb. roasting capacity:



Upgrading it to 5 lb. capacity presented new challenges; one was additional heat was needed; seal issues encountered, bean column issues; and so forth. The video is again long; it is about 10 videos spliced together. A work in progress; contains some good information for those interested. Comments and suggestions encouraged.

Thanks,
Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
First thought - Most fluid-bed roasters show a very rapid increase
in fluid action as the beans become lighter. In fact. My roaster's blower is at 90% at the start of each roast and is turned down to around 40% buy the end and then back to 90% for cooling. Therefore, I must assume that due to the rather large coefficient of thermal expansion of the aluminum causes variable vacuum leaks as the material gets hotter, and the loss of vacuum reduces the air-flow required to cool the heating elements.
 
coffeeroastersclub
I am hoping that some high temp silicone gasket I have coming will solve the sealing issue that I believe it may have. The extensions bottom seal is now aluminum, so I will put a gasket around that so it will be silicone gasket against silicone gasket. The top where the lid fits on I am going to put a silicone gasket ring around that so the top will fit as secure as it does on the 2 lb. setup. I still need to find some ceramic bobbins to wrap the kanthal heater coils around; can't find it except on aliblahblah and I hate doing business through them.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
coffeeroastersclub
oldgearhead wrote:

I'm pretty sure any heat gun element will burn out if the air flow drops below a certain rate while at a certain wattage. I suspect every heat gun engineer knows what that number is. All I know is:
1) I ran mine at 1100 watts for 20 seconds at 0.0 m/sec and burned several beans, but the element was still alive.
2) My flow rate is rarely less than 4 m/sec.
3) Anemometers aren't very expensive.


So I got my anemometer today. So we are looking at 4/m sec as a good level for these type of master appliance elements to prevent burnout?

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
Len,
My numbers are taken with un-heated air exiting from the three-inch diameter pipe located at the top of the RC. For the Five Pound Sucker I would suggest you get everything sealed, load it with beans and get some baseline air speeds with fluid-green-beans. Remember, air measurements are proportional to temperature, so always try to measure ambient air. With the FPS that should be easy....you must establish your own ranges.
 
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