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JackH
12/14/2019 4:07 AM
I read somewhere that higher elevations have faster roast time and require somewhat lower temperatures. air is thin and has less Oxygen

allenb
12/14/2019 12:44 AM
Yes, 1st off, you must use only Panama Esmeralda Geisha beans and be sure to only roast on Saturdays. Actually, this isn't completely true. Please post in all about roasters forum. Thx!

wjohndon4566
12/13/2019 10:36 AM
I’m at 9,000 feet elevation, is there any special adjustments that need to be made to roast using an SR 540 at this elevation?

snwcmpr
12/07/2019 9:29 AM
roar

snwcmpr
11/27/2019 11:44 AM
greenman

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5 Lb Roaster Perf Plate Design Help!
pisanoal
tamarian wrote:



I am more hands-on and find that taste trumps theory. Most theories on roasting are based on drums. Each roaster has its own characteristics. So it more important to see how does it taste?

Where did you place ET probe? Some locations may reach even higher if air flow is too high. With fluid beds you just need to initiate the circular movement and gradually decrease air flow as the roast progresses.

If you place ET probe above the beans, away from the air flow, it should not be much higher than BT. If below perforation it will a lot higher, depending on metal and thickness.

Getting rid of dead zones with steeper angle is crucial to taste (avoiding taste defects) and safety.

Adjusting perforation may help with efficiency, and possibly taste. But you need a reference point with taste, to see if any changes are worth it. But it may be easier to just adjust air flow as a starter.



So my ET probe is about an inch below my perf plate, however, i am also scorching my silicone gasket on my door which is rated for 600 degrees. Thats in the bean spout area above tbe perf plate. So i guess its probably ok to go a little higher then recommended ET since the beans arent quite seeing that high of temp? 675 still seems sway to high though.

I am definitely getting scorching on the beans too but not sure if its related to bean movement and dead spots or super high ET.

It also tastes scorched which makes sense since some beans are.

Anyways, after i get the steeper plate on the back wall in place, bean movement will be greatly improved and we will see what things look like from there. Hopefully i can get a roast with a reasonable ET and I can get a reasonable taste test in.

Did you do a build thread on your 10kg roaster?
 
CoffeeInterest
pisanoal wrote:

CoffeeInterest wrote:

Perf plate does matter, but less so with an asymmetrical chamber. You have enough clearance to accommodate the batch size you want.

You need the right blower as well. My experience has been that the Ametek 122170-18 is the best you can use.

Additionally, you probably have too much shielding around your burner to prevent a good consistency of air and flame. Brush flame torches like the Gods BP’s, the Seiverts, Exacts are absolutely perfect for this. They won’t blow out.



Really sorry, I completely missed this post. I really appreciate the feedback.

With your blower recommendation, are you suggesting I'm lacking in CFM or pressure? Just looking to compare my blower to the one you recommended.

I do have a good bit of shielding around my burner, but I'm not sure id say its too much preventing the consistency you are talking about. I could see having trouble maintaining heat that way? But I have plenty of heat getting to my air stream, and it does not seem to fluctuate wildly.


It’s all about pressure when you get into the bigger loads. CFM is related, but it’s more on how well the loft motor can handle 6-10# or bouncing beans on its air bed. My first motor struggled a lot at 6lbs. The Ametek I shared easily lofts more than 22# of green.
 
renatoa
At 260–270 °C; 500–518 °F is cellulose melting point
https://en.wikipe.../Cellulose
His 600 F rated silicone gasket is scorching... so the degrees are there, whatever is the ET probe placed... what to say more...

These are facts, not related to drum or a specific roasting method.
 
pisanoal
renatoa wrote:

At 260–270 °C; 500–518 °F is cellulose melting point
https://en.wikipe.../Cellulose
His 600 F rated silicone gasket is scorching... so the degrees are there, whatever is the ET probe placed... what to say more...

These are facts, not related to drum or a specific roasting method.


I agree. And that gasket is in contact with the beans. So regardless its currently not transferring heat efficiently to the bean mass.
 
pisanoal

It’s all about pressure when you get into the bigger loads. CFM is related, but it’s more on how well the loft motor can handle 6-10# or bouncing beans on its air bed. My first motor struggled a lot at 6lbs. The Ametek I shared easily lofts more than 22# of green.


Thats what I assumed but wanted to make sure i wasnt missing something. Thr motor im using is rated for 120" WC. So I should have plenty of pressure. The flow is rated at 95 CFM. So the big difference between the one you recommended and the one i have is the air flow.
 
pisanoal
I was away this weekend and unable to do anything on this project but think about it. When I got home, I cut a piece of acrylic to make a steeper angled plate "all the way" down to the perf plate instead of just at the back corner. Bean mass movement was significantly improved, spouting characteristics were not but I think that's ok.

What was changed that will help me control the heat transfer is I can move the beans a lot better with a lot less air. Before, I was having to really loft the beans in order to get "satisfactory" movement in the back corner. So I'm hoping this solves my heat issue.

I don't want to spend the $$ for the fab shop to TIG weld this thing back in there for me, so I think ill just tack it in there and make it air tight with rtv instead of seal welding it.


Some thoughts: I think that with a cylindrical RC, you don't get dead spots as easily as with a square. To combat the dead spot issue, a steeper than 45 degree angle seems to be a really good idea for higher roast volumes. Thanks goes to tamarian for sticking that rock in my shoe. I'll check back after I get to try a roast.
 
pisanoal
CoffeeInterest wrote:

pisanoal wrote:

CoffeeInterest wrote:

Perf plate does matter, but less so with an asymmetrical chamber. You have enough clearance to accommodate the batch size you want.

You need the right blower as well. My experience has been that the Ametek 122170-18 is the best you can use.

Additionally, you probably have too much shielding around your burner to prevent a good consistency of air and flame. Brush flame torches like the Gods BP’s, the Seiverts, Exacts are absolutely perfect for this. They won’t blow out.



Really sorry, I completely missed this post. I really appreciate the feedback.

With your blower recommendation, are you suggesting I'm lacking in CFM or pressure? Just looking to compare my blower to the one you recommended.

I do have a good bit of shielding around my burner, but I'm not sure id say its too much preventing the consistency you are talking about. I could see having trouble maintaining heat that way? But I have plenty of heat getting to my air stream, and it does not seem to fluctuate wildly.


It’s all about pressure when you get into the bigger loads. CFM is related, but it’s more on how well the loft motor can handle 6-10# or bouncing beans on its air bed. My first motor struggled a lot at 6lbs. The Ametek I shared easily lofts more than 22# of green.


I tried my new angled plate design and it helped a little but was still having issues with the temperature. I also had to turn the air back up at the end of the roast to keep beans moving which i thought was really odd. I hypothesized that maybe the dlow falloff at the pressure required to loft the beans was significant enough to not be able to deliver enough BTUs.

I tried two blowers tonight and finally had a successful roast! I was able to keep my ROR where i wanted and the ET stayed under 500 degrees. I was stuck on having enough pressure because that seems to be what people think is most important, but the pressure vs flow curve definitely comes into play when pushing the limits of the blower pressure.

The blower you recommended is almost twice the CFM at close to the same pressure so i think it would act as my two blowers. Do you see any issues with this? How quiet is the blower you recommended? Looks like a low power draw too? Do you have a source that isnt $200.
 
allenb
In looking at Dans spouting bed tests in the downloads section, it makes sense you would need more than 100 cfm to loft and effectively agitate 5 lbs +. These tests are done with a totally different roast chamber and relatively shallow bean bed depth compared to yours and yet show that at 5 lbs +, need more than 100 cfm.
allenb attached the following image:
dans_spouting_tests.png

1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
allenb
I was stuck on having enough pressure because that seems to be what people think is most important, but the pressure vs flow curve definitely comes into play when pushing the limits of the blower pressure.


Good point. A regular fan or blower curve will show x flow in cfm at x static pressure. As we start to approach the flow limit of a particular blower, pressure drops quickly. Pressure is important but remember that most fluidbed roasters require no more than around 20" water column to get even the most demanding bed of beans lofting and many only need less than 10". It's unfortunate that most spec sheets for vacuum blowers show only the air flow through x size hose port and maximum pressure/vacuum in inches of H2O at deadhead (no flow). To me, the most important spec to us roaster builders for a vacuum motor is cfm since all vacuum blowers will have way more static pressure capability than we will ever need. A vacuum blower capable of 200" pressure or vacuum but can only muster 50 cfm through a 2" port is useless to us.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
allenb
In looking at the static pressure/cfm chart amatek publishes for the blower you're thinking of using, it will move a lot of air at high static pressures. At the static pressure you're likely to be encountering in order to loft the beans effectively (somewhere in the 20's, looks like this fan will do around 150 cfm which should give you good headroom and not have to run it full tilt and will be quieter.

Model: 122170-18
allenb attached the following image:
84_amatek.png

1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
pisanoal
Super useful information! Thanks for sharing that. I have been looking at datasheets for blowers and comparing, but i haven't really had a good idea as to what i was shooting for. All i really knew was the two blowers i was using in parallel were working great. Now i just need to decide if I want to spend $200 on this blower vs 60ish to add a second blower. With your flow chart though and the info on 20" WC required pressure, I can look for some alternatives.
 
allenb
On deciding on 2 versus 1 larger blower, it's not uncommon for medium sized fluidbeds to have two blowers so don't feel that if you design around that format that you are cutting corners or being unconventional.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
CoffeeInterest
pisanoal wrote:

CoffeeInterest wrote:

pisanoal wrote:

CoffeeInterest wrote:

Perf plate does matter, but less so with an asymmetrical chamber. You have enough clearance to accommodate the batch size you want.

You need the right blower as well. My experience has been that the Ametek 122170-18 is the best you can use.

Additionally, you probably have too much shielding around your burner to prevent a good consistency of air and flame. Brush flame torches like the Gods BP’s, the Seiverts, Exacts are absolutely perfect for this. They won’t blow out.



Really sorry, I completely missed this post. I really appreciate the feedback.

With your blower recommendation, are you suggesting I'm lacking in CFM or pressure? Just looking to compare my blower to the one you recommended.

I do have a good bit of shielding around my burner, but I'm not sure id say its too much preventing the consistency you are talking about. I could see having trouble maintaining heat that way? But I have plenty of heat getting to my air stream, and it does not seem to fluctuate wildly.


It’s all about pressure when you get into the bigger loads. CFM is related, but it’s more on how well the loft motor can handle 6-10# or bouncing beans on its air bed. My first motor struggled a lot at 6lbs. The Ametek I shared easily lofts more than 22# of green.


I tried my new angled plate design and it helped a little but was still having issues with the temperature. I also had to turn the air back up at the end of the roast to keep beans moving which i thought was really odd. I hypothesized that maybe the dlow falloff at the pressure required to loft the beans was significant enough to not be able to deliver enough BTUs.

I tried two blowers tonight and finally had a successful roast! I was able to keep my ROR where i wanted and the ET stayed under 500 degrees. I was stuck on having enough pressure because that seems to be what people think is most important, but the pressure vs flow curve definitely comes into play when pushing the limits of the blower pressure.

The blower you recommended is almost twice the CFM at close to the same pressure so i think it would act as my two blowers. Do you see any issues with this? How quiet is the blower you recommended? Looks like a low power draw too? Do you have a source that isnt $200.

Kleen-Rite sells them cheap. It's as loud as any other Ametek I've used. This blower is very special and will loft a lot of beans for you.
 
pixelsmithy
allenb wrote:

The angle on the 1+ bag Sivetz I used to roast on was somewhere near 45 degrees and the throw of the beans was up and not toward the vertical wall.


This makes sense because air will follow the path of least resistance. It isn't going to turn a corner just because you have tilted a round hole. Instead the air will continue to flow in the same direction, only the round hole has now become elliptical, thanks to the tilt you have put in the perf plate. This means you are effectively reducing the amount of hole-square-inches and so may need more holes than you would have in a flat perf plate, to achieve an equivalent air flow.
 
pisanoal
pixelsmithy wrote:

allenb wrote:

The angle on the 1+ bag Sivetz I used to roast on was somewhere near 45 degrees and the throw of the beans was up and not toward the vertical wall.


This makes sense because air will follow the path of least resistance. It isn't going to turn a corner just because you have tilted a round hole. Instead the air will continue to flow in the same direction, only the round hole has now become elliptical, thanks to the tilt you have put in the perf plate. This means you are effectively reducing the amount of hole-square-inches and so may need more holes than you would have in a flat perf plate, to achieve an equivalent air flow.


My intuition and experience disagree. The air will turn the corner and flow perpendicular to the perforations. The best illustration of this is drill a hole in a pipe carrying air (or water). Which way does the air blow out of the hole? When the bean chute was open with this design, the air was definitely blowing perpendicular to my perf plate. I think your comment about reducing the effective area tells the story, if that were the case that is not the path of least resistance. Path of least resistance by definition in this case would be where it has the most area for flow.

The overall trajectory of the bean spout is away from the back wall because the air hits the back wall and travels up along it with the bean chute closed. My concern was not which way the spout was going to travel once over the bean bed, but that the beans at the point they entered the air stream by the perf plate would be thrown to the back wall creating more resistance. Also, the air would lose energy and the air stream becomes effectively narrower. Flattening the perf plate did make a significant difference for my RC. I think I still could have been successful with the angled perf plate knowing what I know now about required CFM, but I'm still happy with the flat perf plate.
 
pisanoal
Quick update. After thinking i had the problem solved, I have been trying to get 6 lbs to roast right. It has been back to the same issues of ROR tailing off a few minutes into the roast.

After discussing with my buddy, he suggested checking my ET thermocouple which for some reason i hadn't considered being an issue. One of my concerns with placing the TC under the perf plate from the beginning was that radiant heat from my burner would cause issues with my TC reading. So I stuck some cheapo TCs with a handheld meter in there, one below the perf plate and one right above.

The ones below agreed, the one right above was almost 200 degrees lower! I'm sure when there are beans in there, the difference isn't as dramatic, but still definitely an issue. Another reason I thought my ET was high is my door gasket kept scorching and i thought it was rated to 600. I checked the temp rating and its only 425. My RTV I'm using is what's rated for 600 +... I have since changed the door design so the gasket isnt in the direct stream of hot air anymore and havent had scorching issues since. Also, on my TC test, i had to get my ET probe to read over 700 F before I was at around 480 F above the plate. Definitely explains a lot of my problems well.
 
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