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Bobby M15's drum
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allenb |
Posted on 06/27/2015 4:17 PM
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Administrator ![]() Posts: 3335 Joined: February 23, 2010 |
Here's an old document that shows how to get a pretty close approximation of the inner and outer radius of a sheet metal flight (vane in our case). It takes a while to figure out what the abbreviations are referring to but it eventually makes sense. They use a squiggly r for the minor radius which can be hard to see in the drawing where many abbreviations are crammed into the ID so you might need to blow it up a bit to read it. The calculations give you one vane traveling 360 degrees. For calculating the radius values for a vane only traveling 90 degrees (for a 4 vane drum) I'm assuming you will need to use (pi x diameter) /4 in steps 1 and 2 for the right triangle base formulas instead of just pi x diameter. Hopefully this helps with drawing up the vanes and hopefully their and my math is correct as well.
allenb attached the following file:
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
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JackH |
Posted on 06/27/2015 4:21 PM
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![]() Administrator ![]() Posts: 1779 Joined: May 10, 2011 |
Allen, we should put that file in the downloads area if it's not already there.
---Jack
KKTO Roaster. |
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allenb |
Posted on 06/27/2015 4:26 PM
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Administrator ![]() Posts: 3335 Joined: February 23, 2010 |
Good idea, I'll get a copy posted there. Allen 1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
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BobbyM15 |
Posted on 06/28/2015 12:29 AM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
Thanks for posting this Allen, I am going to get after it!
Coffee is a language in itself.
Jackie Chan |
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BobbyM15 |
Posted on 07/01/2015 6:47 PM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
Fabbing up some vanes today, hopefully get then done tomorrow. I am going with a straight blade arrangement. I'll see if that works. Here is a calculator that some might find useful. https://www.easyc.../helix.php Coffee is a language in itself.
Jackie Chan |
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allenb |
Posted on 07/07/2015 7:08 PM
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Administrator ![]() Posts: 3335 Joined: February 23, 2010 |
Quote Ok, the vane radius formulas sheet is now in the downloads section for anyone interested in calculating those pesky vane radius values. Allen 1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
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allenb |
Posted on 07/07/2015 7:11 PM
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Administrator ![]() Posts: 3335 Joined: February 23, 2010 |
Quote BobbyM15 wrote: Fabbing up some vanes today, hopefully get then done tomorrow. I am going with a straight blade arrangement. I'll see if that works. Here is a calculator that some might find useful. https://www.easyc.../helix.php Let us know how the calculator worked out with your vanes and if it was helpful we'll place a link somewhere accessible. Also, let us know what you mean by "straight blade". Allen 1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
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BobbyM15 |
Posted on 07/08/2015 1:26 AM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
Not so much a helix as we normally see, more like the outer vanes here:![]() The calculator worked pretty good. I will post some photos of my drum soon as I get finished welding. Coffee is a language in itself.
Jackie Chan |
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allenb |
Posted on 07/08/2015 8:04 AM
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Administrator ![]() Posts: 3335 Joined: February 23, 2010 |
Those are actually segments of a helix placed in tandem and to me, are more effective in mixing than a continuous helical vane. I used that strategy on my 1 lb drum roaster. Allen 1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
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BobbyM15 |
Posted on 07/10/2015 12:59 AM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
I agree Allen. Here are some pics of where I am right now. Lots of work these roasters LOL. I put some different colored navy beans in to see how it mixed and it did well. That is 2 lbs. of those beans. I think this will be a good 2 - 4 lb. roaster. It is 8-1/2 inch pipe x 12" long. The outer vane angle is right at 25° as per your suggestion in a different thread: thank you! ![]() ![]() Edited by BobbyM15 on 07/10/2015 1:05 AM Coffee is a language in itself.
Jackie Chan |
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M Heyns |
Posted on 07/10/2015 7:03 AM
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![]() Newbie ![]() Posts: 1 Joined: July 07, 2015 |
Hi I am newly registered please keep on posting, I am planning a similar build myself soon! |
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BobbyM15 |
Posted on 07/11/2015 7:34 PM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
How far into the bean mass should a thermocouple go? I'm thinking maybe 1" to 1-1/2"?
Coffee is a language in itself.
Jackie Chan |
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okmed |
Posted on 07/11/2015 8:09 PM
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![]() Newbie ![]() Posts: 42 Joined: August 23, 2014 |
10 times the diameter of the probe.
RAF-1 Extreme (modified B-2K) Hottop with HTC+TC4C, HG-One grinder, Bezzera Strega.
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BobbyM15 |
Posted on 07/11/2015 11:30 PM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
Okmed, Thank You!
Coffee is a language in itself.
Jackie Chan |
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allenb |
Posted on 07/12/2015 8:25 AM
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Administrator ![]() Posts: 3335 Joined: February 23, 2010 |
In addition to the 10x diameter of sheath rule, there's one additional issue to be considered with sheathed sensors which is their tendency to conduct heat into the plate their mounted to as well as into the ambient air on the other side of it which will cause it to read lower than actual. Many commercially made drum roasters will have their probes enter into the front plate and then make a 90 degree bend extending another 2 to 3" or so to ensure front plate conductance error is minimized. One needs to allow 3/8 to 1/2" between the side of the extended sheath and the front edge of vanes to prevent beans from wedging and thumping the sensor. Allen 1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
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BobbyM15 |
Posted on 07/12/2015 8:30 PM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
Great info, thanks!
Coffee is a language in itself.
Jackie Chan |
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BobbyM15 |
Posted on 07/16/2015 2:50 AM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
Making some progress, although not as fast as I would like, but oh well we have other responsibilities don't we lol. Got the welding done and made the perforated drum end. I welded a shaft collar on it so I could remove the back if needed by loosening the collar and slipping the back off. These roasters are a lot of work, but enjoyable to build, if you like building stuff, and I like building stuff! Then there are usually some screw-ups. Like when I ordered my drive motor I wasn't paying attention and ordered an "intermittent duty" motor. It would get hot after about a half hour under load even though it had plenty of ummmphhh. So remember to purchase what you actually need. ![]() At my current rate I will not get it on line until after the first of the year.....bummer! But I still have the trusty BBQ roaster to get me buy. ![]() ![]() ![]() Edited by BobbyM15 on 07/16/2015 3:04 AM Coffee is a language in itself.
Jackie Chan |
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BobbyM15 |
Posted on 07/18/2015 4:45 PM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
Found a new motor, it's a beast and it works well. With 2 lbs. of beans it only draws 225ma.![]() Put some real coffee beans in to try the new motor out. Gotta fool around with it somehow, right? The reverse vanes work well. You can see (sort of, sorry for bad pic) this one picking up beans and moving them back. ![]() Edited by BobbyM15 on 07/18/2015 4:51 PM Coffee is a language in itself.
Jackie Chan |
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BobbyM15 |
Posted on 07/23/2015 4:37 AM
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![]() 1/4 Pounder ![]() Posts: 64 Joined: January 23, 2015 |
I'll be drilling the holes for the burners and doing the plumbing shortly, we'll see if I blow up lol. I am also trying to decide how much space to put between the back of the drum and the rear face plate. I was thinking 2 inches. That should be sufficient for good airflow through the drum I would think. What do youse drum guys think? Coffee is a language in itself.
Jackie Chan |
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Axel |
Posted on 07/28/2015 5:37 PM
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![]() Newbie ![]() Posts: 32 Joined: July 23, 2015 |
Quote Ringo wrote: I think either one would work but I would think the 1/8 inch would be the one I would pick. Any thoughts on wall thickness for a 24"x30" double wall drum? |
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