Hi all,
I'm planning on building a fluid bed roaster for small batches of 100- 250g.
To keep it simple my roasting chamber will be the top from a cocktail shaker with a pyrex glas tube attached with oven-silicone. The Tube will have an outer diameter of 80mm and a length of 200mm (since this is the largest I can get).
As a heating element I plan to use the heating element from a hot air gun at around 1600W. This will be encased in a glas or steel tube as well. And since the spout of the cocktail shaker is small enough I plan to stick the roast chamber just into it.
Temperature contorl will be done by arduino and PID.
Now the Fan-question: I see lots of people using vaccuum motor fans or leaf blower fans, but they are a bit overwpoered for my 100-250g of coffee. I read somewhere that a minium static pressure of 2"H2O is necessary to get small batches of beans moving, so I took a look at digikey for 2 Fans:
https://www.digikey.de/product-detai...378-ND/6192094
https://www.digikey.de/product-detai...045-ND/6580735
They are both quite similiar apart from the size. They both provide a static pressure of ~ 5"H2O at a flow-rate of 56 or 130 CFM. However I have no idea on how to calculate which flow-rate is suitable or if 5" H20 is enough.
If it helps, I calculated that the intake for my roastchamber will be 238mm² --> 19 holes 4mm dia. each.
Appreciate the help :-)
I'm planning on building a fluid bed roaster for small batches of 100- 250g.
To keep it simple my roasting chamber will be the top from a cocktail shaker with a pyrex glas tube attached with oven-silicone. The Tube will have an outer diameter of 80mm and a length of 200mm (since this is the largest I can get).
As a heating element I plan to use the heating element from a hot air gun at around 1600W. This will be encased in a glas or steel tube as well. And since the spout of the cocktail shaker is small enough I plan to stick the roast chamber just into it.
Temperature contorl will be done by arduino and PID.
Now the Fan-question: I see lots of people using vaccuum motor fans or leaf blower fans, but they are a bit overwpoered for my 100-250g of coffee. I read somewhere that a minium static pressure of 2"H2O is necessary to get small batches of beans moving, so I took a look at digikey for 2 Fans:
https://www.digikey.de/product-detai...378-ND/6192094
https://www.digikey.de/product-detai...045-ND/6580735
They are both quite similiar apart from the size. They both provide a static pressure of ~ 5"H2O at a flow-rate of 56 or 130 CFM. However I have no idea on how to calculate which flow-rate is suitable or if 5" H20 is enough.
If it helps, I calculated that the intake for my roastchamber will be 238mm² --> 19 holes 4mm dia. each.
Appreciate the help :-)



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