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Hybrid Drum Roaster build
Things are coming together....... Sat night update... :-)
broeker attached the following images:
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Sunday update..... Might have to revisit the tipping mech.... It's not done yet but it's pretty heavy...... Might have to get some hydraulics involved :-)

Got the drum in... Everything is mint.... & concentric....
broeker attached the following images:
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It's not done yet but it's pretty heavy...... Might have to get some hydraulics involved :-)

Can't wait to see it roasting some beans. Fantastic workmanship!
allenb attached the following image:

1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Sunday update....
Welded everything.
Started fitting drive.
Still have to fab dump handle.
Lots to do still :-(

Can't wait to fire things up........

What do you guys think of exhaust probes for use in the back of the roaster? I mean automotive exhaust probes.... Like the tuners use...
broeker attached the following images:
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Edited by broeker on 08/03/2014 5:12 AM
This is another flat out amazing project. The pictures remind me of Sky Captain and the World of Tomorrow, especially the gull wing mount for the drive shaft. If it had an impeller it could be a submarine.

Ca you tell us a little more about the automotive exhaust probe, I take it you have one "lying around" and want to use it?

Usually probes need to be immersed 10X their diameter, and need to be sturdy enough not to break. But, you don't want too much mass so it can be responsive. People seem to use 4mm-6mm diameter. It can also be tricky to put the probe into the coffee for small batches while dodging vanes etc.

For measuring air temperature, such as the "environment" inside the drum almost anything will do if it is accurate.
Haha thanks Mike, I love the Sky Captain movie :-) Na I don't have any Probes lying around, but the more I look into getting some pretty much everyone has a different opinion... grounded un-grounded... etc. the list goes on, its just a local auction website (to NZ) has some probes for $140 as shown on the attached image, its seems handy they have a fitting I could tap into the rear plate on my roaster..... I stopped my vanes 15mm from the end plate to accommodate some sort of BT probe

broeker attached the following image:
Monday night update - My bean/drum dump mech works perfectly...... No hydrulic cylinders required..... Just a nice rat rod styled lever bar :-) I'm so stoked....
broeker attached the following images:
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OK, for a bean probe you want it shielded, not exposed. If that red cap is not hiding an exposed junction, it may be fine.

I think you can get a good probe for a lot less at Do you know what type you need and/or what you are connecting it to? What are your plans.

Grounded just means the junction is connected to the shield, to make it more responsive. In that case one must isolate the probe housing electrically. Or, an ungrounded probe will still be responsive enough.

You can find a compression fitting elsewhere too but I don't know where.
All systems go........ Did a seasoning batch with some old robusta, then into it... 2kg load.....

The vanes are perfect.... The dump mech is great, the load emptying out in seconds.. Probably on 1/4 power, so plenty of btu's there.......

Got some proper volumes so can now design the cooling tray & chaff collector...

Booya !
broeker attached the following images:
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Moved the roaster to my brothers roastery this evening for a proper test....

First run 2 kg of Colombian it did what was expected ( by the experts in the room...) plenty of power there & very responsive.... The drum vanes appear to be functioning perfectly (thanks Allenb for the help with that :-). )

Second roast 4 kg of Colombian..... Needed a little more power (like still at 1/4 throttle). Perfect result at 17 min.....

It appears like 4kg is the maximum load as on almost dump time the beans had expanded to just allow the odd bean to fall out of the nozzle... That sucker was full :-)

All beans run out of the roaster in seconds once I pulled the dump lever.....

Very happy at this stage. :-)

Now about those thermocouples........
broeker attached the following images:
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So we just ran 32kg through the roaster over 5 hours, using a fan to cool the beans in a wire mesh basket (4kg batches) 8 different varieties....

Everything worked wickedly:-) got some good ideas to improve 2.0

Tested a cyclone/ chaff collection set up (plastic cyclone & bucket)

Next plan, design proper cooling tray & chaff collection based on the mockup.
Thermocouples installed
Bluetooth link to iPad -check
2kg test roast - check
Data logged....

Now if only I knew exactly what the curves ment....... :-)
broeker attached the following images:
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So I installed the roaster & cooling system in The Roast Office yesterday.... Did a couple of trial roasts...... It's looking good........ So far.......
broeker attached the following images:
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My brother on the roast :-)
broeker attached the following image:
So....... Issue 02 x2 is in full effect :-)
broeker attached the following images:
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Very impressive design! bbq
That is an amazing design and build. I too would be interested to know more about the burner as it looks like it really does the job.
Coffee is a language in itself.

Jackie Chan


BobbyM15 wrote:

That is an amazing design and build. I too would be interested to know more about the burner as it looks like it really does the job.

The burner tube is made by a company called polidoro, they have a huge range of sizes & types..... I can't be more happy with it.... Just pick your output and length/diameter and go for it... :-)
So my gas install is coming together along with the rest of the issue 02 build.... Waiting for drives & bearings........ I did use high temp bearings on issue 01 and so have chosen to again..... Mostly because it's been roasting 5 days a week 3 roasts per hour at 4 kg per load since early jan..... Plus weekends when I can get there.... Roastmaster is showing over 8500kg since I installed it........ So one little pump of grease at they're still going strong.....

It was explained to me by the bearing guy that the high temperature bearings have slightly looser tolerances so when they heat up and expand that they are pretty perfect for continuous running at temp ( with suitable lubrication)
broeker attached the following images:
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broeker wrote:

First burner test..... To determine the gap between it and the drum..... ( I've got 20mm of adjustment in both directions)

It's goes better than I had expected. :-)

how windproof are these burners?

where can I order them from?
Edited by Axel on 07/29/2015 4:52 PM
Busy building the Cyclones for my new cooling tray/chaff collector design....

I feel it's important to keep the sizes to a pretty fixed set of proportions ( lots of research out there) mostly based around the diameter chosen....

I've ended up with a twin mirror pair :-). Why will become clearer as I get more fab done......

Happy new year friends :-)
broeker attached the following images:
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Looking good. Are you making your own impellers for these ?


dmccallum wrote:

Looking good. Are you making your own impellers for these ?

I am using two blowers that have been designed for use in "pellet" fire places..... They burn little pellets of wood in an controlled way.... But use blower fans designed to take heat and have straight bladed centripetal fans......... In my experience unless your air stream is 100% free of chaff, the squirrel cage fans clog up...

For the cooling tray I'm fabricating my own impeller.... :-)
Looks awesome! Got a possibly stupid question, how do you add the beans to the roaster? Some sort of removable chute?
Yep rxstar stainless chute and spout.... I tip directly from the container the green beans are weighed into (4kg)

Given it all tips up... It's the easiest way to go.
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