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That would be a cool invention, I have seen those fans your talking about. they sell them at best buy, really neat but man they are expensive for a fan.
If this was brought to the aquatic world it would be a money maker, that's for sure.
 

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Sorry to burst your bubble, but that graphic is very misleading; no doubtably made by the Dyson marketing team because they spent $75 million developing that fan.

Firstly, the bladeless fan is a misnomer because it actually has blades. Just not visible ones, there's a traditional fan in the base that blows air into the circular ring part. This is the majority of the air you feel coming off it. The picture doesn't show this and exaggerates the rest.

And for your idea, it wouldn't work. The bladeless fan kinda makes a vortex that pulls some air along with it. Water has too much drag and doesn't move like that efficiently. As an analogy, you can move water with a fan just as easily as you can swim through air.

Sent from my SM-G935T using Tapatalk
 

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Discussion Starter · #5 · (Edited)
Oh, Mr. MuchDutch, thank you! I admit I was sitting on this curb, dejected, with the remains of my burst bubble wondering what would become of me... When you stopped by this thread, it really cheered me up!
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I intentionally didn't put a lot of specifics into the first post to see what it might reveal. I wasn't clear enough and that confused swmnwdsfishes.

What I am looking for is indeed a use of the venturi principle in water (which we know works) -- like the eductors in reefkeeping, or ring injectors in carburetors.

Instead of the design goal being maximum output velocity or maximum mixing of different fluids via turbulence, I would like to maximize the suction volume vs. the driving fluid volume:


Imagine the above nozzle as a ring with a pass-through middle, like these carburetor boosters but with apertures designed for the properties of water and creating a low Reynolds number after the water-water boundary:


The goal isn't the 15x claim for the air fan. For this application I'd be content with 1.5x in water.
 

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Discussion Starter · #8 ·
That waterbed suction pump claims a 6x flow. That's pretty good and the draw-from-the-bottom is a promising arrangement. (Of course, the Python water change kit uses the same principle, but it's not even close to the shape I need.)
 

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Now this is what I was looking for, the technical details ;)

Ill be stalking this thread from now on lol
Good luck ObiQuiet!
Nate
 

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If I understood you correctly you want to increase the flow without adding more energy to the system (more powerful pumps). I've explained how the flow in ADA tanks is setup. Others have explained it before me. The idea is to get the maximum benefit from the moving water - move all bottom debries toward the filter intake and never let trash linger suspended in the water. Now if that is not your goal then my response is of no use to you.

Imagine a big pot of soup. Stick a teaspoon in the middle of the pot. Start stirring only in the middle. Soon you will notice that all the soup in the pot is involved in a circular motion. So - minimum effort but maximum result. That is how ADA does it too - shoots water across the front glass where there is nothing to hinder the circular pattern. This involves all the water, from the entire tank in a gentle movement.

The filter intake is placed a little high above the bottom. That makes all fine debries to have a tendency to lift off the bottom up and to the side (toward the intake).

The outtake - the Lily Pipe - is exactly the ventury described above. Its shape is such that it actually sucks water in around the perimeter of the glass bulb as it shoots water out in the center.

Big role is played by the shrimp and otos - they constantly disturb the larger debries off the bottom, leaves, decorations.

All that sounds good but at the end ADA tanks are maintained clean in a variety of not-so elegant ways - wire brushes to scrub the rocks and wood, tedious spot vacuuming, and such. It's an illusion but one can learn a lot from the techniques and setup.
 

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Discussion Starter · #12 ·
Thanks for the responses, Niko and TAB.

I'm thinking about an improvement to this idea, originally posted in this thread related to Niko's laminar flow discussions:
Rectangle Line Font Slope Parallel


So, unlike the eductor nozzles, I don't want a forceful single point flow. Instead, think about having one of these sprinklers in your tank (yes, I know it's ugly -- it's the principle, not the implementation)


which would induce a larger flow than just what comes out of its own holes.
 
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