Re: Another CO2 Reactor Design
>From: Stephen.Pushak at saudan_HAC.COM
>Date: Wed, 14 Feb 96 19:26:16 PST
>Subject: Another CO2 Reactor Design
[lots of stuff snipped]
>An ideal reactor would have a flow diffuser or expander section which
>directed the flow downwards and such that small CO2 bubbles will tend
>to find a meta-stable equilibrium point where the downward flow
>resistance is roughly equal to the upward buoyant force. Let me try
Good idea Steve. However I think you'll need to refine it a bit. This
"meta-stable equilibrium point" is not highly desirable as CO2 from
yeast is not pure and these other gasses tend not to dissolve. They get
collected in the cone if this condition is reach. You'll need an outlet
for them somewhere along the cone.
>to make a picture of this hypothetical reactor:
> <-- CO2
> || _______
> Venturi---->|| [-------]==]
> /=================----++---/ | |]=+
> 1/2" PVC tube---->/ . <-o <-o <-o <-o | |
> / . ./==============---------\ | |
> | o | Powerhead---->| | |
> Max flow velocity--->|. | [______] |
> /.V .\ [ ]
> /.O. O \<---- Inverted Cone Reactor [ ]
> Entrained / ./.\ . \ [_]
> CO2 bubbles--->O .. o . \
> /.././. \.\ .\ .
> / . o . o . \ .
> Diffuser vanes-->/ ./ . .\. \. \ .
> /./ ./. /.\.\ \..\.\ .
> . . . || \\ . .
> Flow direction------>|| . \\<----Min flow velocity
> . . . \||/. . \||/
> . . . \/ . . \/
>As the chamber fills with bubbles, there would be a limiting
>condition where bubbles start to escape out the sides. Before
>this state is reached, the pressure in the CO2 inlet tube will
>change from negative (relative to ambient) to positive. That
>means that if you opened the CO2 line (say by unscrewing the
>cap on the CO2 yeast bottle) water would flow out the tube
>and start siphoning so a check-valve would be a good plan.
>Otherwise, shutoff the powerhead before disconnecting the
>yeast bottle. If it works really well, the CO2 should pretty
From my experience, you should not shutoff the powerhead while the yeast
bottle is connected. Due to the venturi effect, the pressure in CO2 tube
is lower, turning off powerhead would initially let water get into the
tube before the CO2 pressure from the bottle building up again. Yes, a
check-valve is recommended but for the above reason. It is best to
turnoff the powerhead before opening the cap to avoid air from bubbling
out from powerhead. I avoid shutting off the powerhead altogether by
having two bottle in a gang with shutoff valves. You could also do that
by installing a shutoff valve on the cap.