Homeroasters - Home Roasting Coffee Community » BUILDING A ROASTER » Fluidbed Roaster
Who is here? 1 guest(s)
Page 2 of 2: 12
 Print Thread
Fan suggestion for 250g (0.5lbs)
oldgearhead
Top  #26 Print Post
Posted on 07/07/2016 6:55 AM
The two sheet concept might work if placed at an angle. Remember after a portion of the bean column is propelled to the top it must return back to the bottom (gravity). The beans must circulate constantly. Also the heat transfer is mote efficient if all the beans are in constant contact with each other...
No oil on my beans...
 
JETROASTER
Top  #27 Print Post
Posted on 07/07/2016 4:38 PM
Yello, I'm looking forward to the results from the "adjustable plate".

I will second Allen's point about building pressure below the plate. Allowing the beans to be the primary source of back pressure makes for pretty random bean movement.
Vacuum blowers will certainly support that design.
Best, Scott
 
TeaTastesBetter
Top  #28 Print Post
Posted on 11/22/2016 6:19 AM
Hi, I've been a read-only visitor to this forum for the last year. But, I have some positive and negative experience from the kind of server fans you posted.

I've tried two server fans that were similar to yours (100CFM and about 2" H20) with negative results. But, then I found this which is about $10 when ordering from China:
http://www.delta....4x25mm.pdf

It's only 4" H20 but initial testing shows it may be enough for 250g roasted beans with the proper RC. I've made plastic prototypes that give decent lift and rotation depending on the geometry. A wider tube (about 6") with a conical base has worked best this far.

I am a bit limited when it comes to construction options since I don't have access to welding equipment. Therefore, an asymmetric RC may be out of the question. My current plan/hope is to use a 1 liter conical stainless measuring cup with holes drilled in the bottom but I have to do some more testing to see what shape and angles work.
 
btreichel
Top  #29 Print Post
Posted on 11/22/2016 11:05 PM
Yeah I've worked with a fan like that and found about a 250 gram limit. Never found one bigger in a server type fan.
 
Page 2 of 2: 12
Jump to Forum: