Backyard Aquaponics
A place to discuss aquaponics

I was looking for a venturi design for my chift pist. Found this. Not sure if has been posted before. Hope it works cause you cant edit on this forum.
http://leisure.prior-it.co.uk/venturi-pond-aeration.shtml

Thanks for sharing. That is one thing I do not have on my system.

Good link.

good link indeed
but please remember that here is no such thing as a free ride where energy is concerned:
Venturi's are very simple and interesting devices for mixing two media
but to my opinion only attractive when special challenges have to be met
like when dosing corrosive liquids into water
dosing air into water is not one of these special challenges
a Venturi will work for this
but as a Venturi always incorporates a restriction
this will go to the detriment of your pump volume, thus annihilating all aeration profits
with a negative balance to boot
there is one exception: if you can use gravity to action the Venturi, there is no loss of energy
that is what I try to do in my high gain passive oxygenator:
http://backyardaquaponics.com/forum/vie ... f=9&t=4101
read also the explanations posted there

frank

I love venturis, we use them in all of our large systems...

Frank, I can't run sketchup. Do you mind posting a picture of this?

in a very few words (just name the concepts, don't need to go too far off topic) what strategy would you suggest for adding more air to a system like this:
http://www.backyardaquaponics.com/systems.html
see the sketchup images about halfway down to understand the concept - pump in fish tank to growbeds, gravity to sump tank, pump in back to fish tank. I ask because this is how a huge portion of existing systems (including mine) are designed.

Also is there any reason the venturi that cockroach linked to can't be installed on a gravity line?

Not enough pressure?

Yeah I cant either Frank, would love to see pix.
I have a little more pump pressure than needed so I might give the venturi a try anyway.

I like venturi's also. I run two commercially built ones - only cost about $20 each when you factor in the fittings and theings for them it is hardly worth me building my own unless I needed a fair few - which I may in future I suppose.

is there a reason you can't run sketchup?
it's a wonderful tool and you can download it for free :
http://www.google.com/sketchup/download/

here is a pic of the drawing:

push the crtl + and crtl - buttons to zoom in and out


see my drawing of low head aquaponics:

push the crtl + and crtl - buttons to zoom in and out

some ground rules:
pump only straight upwards through a slightly over dimensioned[/i] stand up pipe that is kept [i]as short as possible
this will give you highest pump performance
next you can use only gravity
use only gutters, not pipes for all horizontal distribution and return piping
use preferably open top gutters
I use square rain drains 100 * 100 mm in which I have drilled lots of 80 mm holes in the top
(use the gutters for NFT but only grow vegetables in them that are quickly harvested as I have been warned that roots may clutter the gutters after time)
make sure water flow is turbulent, not laminar, in the gutters to expose more water surface to air by laying an object alternatively from side to side in the gutters
insert the high gain passive oxygenator or a flowform wherever you want

if you have no sump but only a fish tank imagine the drawing without the fish tank and the upper gutter
the sump then becomes your fish tank

if you have several growbeds, use another same type gutter to return the water to the sump/fish tank


spot on, Ozzie
actually, a standard Venturi has two restrictions: one on the water and one on the air
which diminishes it's efficiency even more
that is not the case in my high gain passive oxygenator design: both water and air are free flowing
the cascades cause the speed changes necessary for the Venturi effect


I love all animals, great and small
i.e. elephants and mice
still I would not use either for transport
Venturi's are very interesting for special applications
AP is not one of them

frank

Frank,

Energy efficiency is not my major concern, and venturis work exceptionally well in aerating the water coming back from my drain tank.

How can discount them as having no use in aquaponics, for me they suit the purpose perfectly.

forgot one important thing: orientation
dispose everything so that the growbeds are not shaded by the gutters

use sketchup to preview your setup from all sides

frank

I accept your position and that of others, whose concern is not towards energy efficiency, Joel,
please accept mine and that of others to which energy efficiency is very much of concern

just like you and all other helpful members I only post my opinion on a certain subject
and you cannot deny that I thoroughly motivate each time

nobody is forced to accept or apply my suggestions
I do not even ask that they be considered by whom might think is not concerned

they might, Joel, to you and to others who are not concerned with energy efficiency
but for people who are concerned with energy efficiency they should be considered as far from working "exceptionally well in aerating the water"

like of any item the drawbacks of Venturi's should be explained,
not only he advantages
information should address all sides to all major issues, especially the ones brought forward as being attractive

I could stay silent and have an easier life (believe me, these posts take me a lot of time)
but I have learned so much from your forum that I feel obliged to some kind of payback


I can accept that, as you are not concerned with energy efficiency
please don't deny me the right to discount them from my point of view

in all friendliness,

frank

you know what, if it works it works, and if it isn't broken, don't try to fix it..( pissing me off reading this shite over and over ) ...make up your own minds. Arguements like this can go on and on, right now in 2008, it is here nor there, maybe soon, energy efficiency will really matter. If I turn off two air cons and make sure no extra lights are burning, does that count ????? damn doubt it... you get so picky mate, look in your own back yard first...

You could rig up a Venturi for return water. No added power for a little more o2.