Green Coffee Buying Club
Coffee Discussion boards => Hardware & Equipment => Topic started by: kevsnova on March 04, 2016, 04:27:55 PM
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Has anyone had any luck with controlling propane flow with a pid and variable solenoid valve?
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There is a bit more to it than air volume. You also have to look at heat load and heating capacity. If you are moving the heat out faster than you can put it in, well, beans don't cook. That does sound like it should loft them pretty good though.
Aaron
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I wonder if you could google around enough or deconstruct a Sono enough to just copy what they did on cfms and chamber size.
It's a known working unit.
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I wonder if you could google around enough or deconstruct a Sono enough to just copy what they did on cfms and chamber size.
It's a known working unit.
IMO its very close to a perfect roaster. I hear they have to pay royalties as do all commercial (non home made) fluid bed roasters to someone who owns a ton of patents on the process. I assume its sivetz.
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There is no mention of the c.f.m. on the sonofresco roaster, I found a link suggesting that the blower is the same from a Whitfield pellet stove.
I plan to buy Kanthal wire and make my own heating element.
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Perfect Roaster...hahaha.
The perfect Roaster is indeed the Huky. :P
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I have found a 430 cfm blower with adjustable speed control, I tested it in a mock up 5" diameter chamber and it will lift 3lbs of green beans easily. I had cut out some fire brick and placed my 4 heating elements which I made from kanthal wire in the brick, Which works out to around 6,440 btu/h.
I will test the blower with the heating element sometime tomorrow and see what mods I have to do to the elements.
So far I am keeping everything at 115 volts. The system will draw 16 amps in total unless I need more heat. I'll find out tomorrow.
I will soon start on a cyclone to catch the chaff once my element issue is taken care of.
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OK so my heater element will not produce. Has anyone had any luck with controlling propane flow with a pid and variable solenoid valve?
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3 Lbs id go with at least 5 KW to get it going good. That's going to be a bit rough with 120 vac.
Aaron
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I am going propane, One small burner, and one kiln burner linked to the ssr from pid.
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Fwiw - the sort of squirrel-cage fan you point to may work, but only b/c you are loading the blower with a lot of back-pressure and reducing the flow. 430CFM will blow green beans right out of a 5" pipe [it's above the bean terminal velocity ~15m/sec], and moreso once roasted. Further it takes ~58kW or 200kBTU(/hr) to heat 430 scfm of air to 480F. !
So in reality you can't likely heat more that say 100scfm to roasting temps w/o a massive heater, and you can spout (not lift) a bean bed with a lot less than that - IF you design the chamber right.
Many consider the 2-stage blowers (like Lamb Ambetek central vac blowers) with ball bearings to be a better choice. The cfm rating is lower,and the flow doesn't drop-off quickly with back pressure.