10 min $10 DIY aerated compost tea ACT brewer

[420247]

I thought this is the better thread to mention that if you have a choice, when selecting a cone bottom tank for creating a bioreactor (compost tea brewer) that you are way better off getting one with most of the height taken up by fairly cylindrical walls and a fairly mild angle sloping to the exit hole.

This (IME) narrows the vortex, slowing down the 'suction' and provides a higher rate of dissolved oxygen. This is one reason the 5 gallon (cooler) water bottles like Dark used are so good.

Please explain this part a little more, "This (IME) narrows the vortex, slowing down the 'suction' and provides a higher rate of dissolved oxygen."

When you say "There are many who claim that running water in a vortex pattern comprised of multiple mini vortices changes the properties of water beneficially. I remain dubious but open-minded. You can form your own opinion on this subject. One thing a vortex brewer is very good for is ensuring a full circulation of all the water and compost added. There can be no ‘dead zones’; none of the feared anaerobic pockets!!"

"The vortex for many is important. To me it just ensures a really thorough mix of water and inputs. The airlift is what is responsible for high dissolved oxygen content."

 

[Microbeman]

Sorry if my expression was confusing. I wasn't really relating the DO2 to the vortex but rather to the cavity size and rate of passage and weight/pressure of water. Storch has written about this (concerning shape of tank) but I could not find it right now. I believe it also has something to do with the weight of the water column; eg. height vs. weight. (cylinder vs. funnel)

 

[c-ray]

420247.. your brewer will get a stronger, deeper vortex if you point the return pipe to the periphery..

 

[420247]

Thank you! I'll try that c-ray

 

[420247]

Sorry if my expression was confusing. I wasn't really relating the DO2 to the vortex but rather to the cavity size and rate of passage and weight/pressure of water. Storch has written about this (concerning shape of tank) but I could not find it right now. I believe it also has something to do with the weight of the water column; eg. height vs. weight. (cylinder vs. funnel)

This is still not making sense to me....

I found this:
http://en.allexperts.com/q/Physics-1358/2008/10/water-pressure-2.htm

QUESTION: Hi, the question is as follows. Lets say I have a funnel 10 feet tall and a cylinder 10 feet tall, both filled with water. At the base of the funnel and the cylinder is the water pressure the same. I know the in the funnel the pressure is lower at the base because the piping narrows, but what I am unclear about is if the funnel has more area for water doesn’t that mean that the pressure would be more in the funnel because there is more water above it?

The water is not static its moving.
Thank you

ANSWER: Hello Emmanuel,

Let's start with the basics.

Pressure is force per area:
p = F / A

The pressure in an incompressible liquid (like water) only depends on the height of the liquid column above - not on the volume of water.

So even if there may be more volume of water in the funnel than in the cylinder, the pressure only depends on the height of the water above. The weight of the additional water in the funnel is supported by the sides of the funnel.

Now because of the equation above, which can be transformed into
F = p * A
(force is pressure times area)
the total force on the base area of a funnel or cylinder is of course proportional to the area itself, so if the funnel has a smaller base area than the cylinder, the total force on the funnel's base area is smaller, even though the pressure is equal for equal filling heights.

Only in very narrow pipes (less than a millimeter in diameter) is the pressure reduced by the so-called capillary effect:
http://en.wikipedia.org/wiki/Capillary_action

See this page for more information on this topic;
http://en.wikipedia.org/wiki/Hydrostatics

I hope I could help you a bit.

Peace,
Kevin

Lets say all tanks have 1 1/2" FTP fittings

(cylinder) 15º CONE BOTTOM TANK 55 gallon 23 x 39
http://www.denhartogindustries.com/wp-content/uploads/product-pdfs/CB0055-23.pdf

(funnel) FULL DRAIN INDUCTOR TANK 60 gallons 30 x 38
http://www.sandiegotank.com/images/den_hartog_main/Den_Hartog_PDF/INDUCTOR TANKS/INFD60-30.pdf

The funnel would have less pressure but still hold more water than the cylinder because of the 1in. height difference? Is that right?

And/or the force is the same because the base is the same? (1 1/2" FTP fittings)

 

[Mia]

The force is gravitational which means F=mgh(mass x gravitational constant x height) so that the greater the h=height, the greater the force(F).
So that if p=F/A, than the greater the h, the greater the F, the greater the p...
I'm not really sure if other factors come into play, but if not that should cover it I believe.

On second thought I take that last sentence back.
There are different amounts of mass at different heights in each configuration so one would have to integrate these masses over the height to calculate the total force and I'm not up for that lol, although it's not that complicated...you would need to define the mass as a function of the height and incorporate that into the equations....
I doubt they would be that much different given the similarities between the two...

 

[Microbeman]

BUMP A MOFO STICKY MOFO

 

[W89]

bump

 

[Microbeman]

ditto

 

[W89]

I'm going to order one of those bottles that are used in drinks machines and make a vortex brewer.. cone bottom tanks are too expensive and I would imagine the bottles work just as good

 

[Old_Headbanger]

This is a great, simple design. Love this setup on a 5 gal.

 

[DARC MIND]

heady B!!

hope all is well with you brother

 

[Microbeman]

I'm going to order one of those bottles that are used in drinks machines and make a vortex brewer.. cone bottom tanks are too expensive and I would imagine the bottles work just as good

Yes. Haven't you seen Darkman's

 

[canna woop!]

BUMP A MOFO STICKY MOFO

what's the deal with the need to bump sticky's? I thought that was the point of a sticky, it doesn't need a bump. eh...

 

[schwagg]

i guess you need a bump. BUMP A MOFO STICKY MOFO!!!

 

[Rednick]

And/or the force is the same because the base is the same? (1 1/2" FTP fittings)

The force is going to be the same, roughly, because the column of water will be the same. While the effects of friction could be considered with funnel versus the shallow bottom, that will all be negligible because of the fitting, as you stated.
Don't let the pressure vs. area, as a function of are, get confused with your force. In science these constants aren't always defined as well as they should be.
Your deciding factors in force, or flow, will be: gravity, displacement (from the air), friction (most likely at your choke point, the fitting/tubing will far exceed anything from the vessel or fluid).

To answer your question with the shape versus pressure, I guess the easiest thing would be get a kitchen funnel fill it up with water and time the drain, then put same size hole in bottom of two liter, fill with same vol water, and let us know
Everybody is a scientist, they just don't know it.

But I think regardless of the 'support' provided by the funnel versus shallow, the opening is the relief of the pressure and thus the area you are searching for as the constant in your equations.
Conversely if it didn't have an opening, then that pressure would be displaced along the all it touches, like building support.

 

[Microbeman]

To answer your question with the shape versus pressure, I guess the easiest thing would be get a kitchen funnel fill it up with water and time the drain, then put same size hole in bottom of two liter, fill with same vol water, and let us know

In this case one would need to set up an airlift return to the 2 litre funnel and vessel and measure the difference in DO2 and observe/measure the velocity of the vortex.

 

[GanjaAL]

For those who use teas in coco... what type of pump are you using to water with in your rez?

 

[Old_Headbanger]

sticky..

sticky..

Can we sticky this again? Great thread.

 

[unclefishstick]

this is a good reason to use the report post option people,i already got this one and the main compost tea thread,if you see them report them and they go away...