How about ultrasonic foam fractionation?

[stugray]

I was watching one of those fog making machines that make water fog from an ultrasonic transducer beneath the surface of the water.

Here's a place that sells them for ponds: http://www.mainlandmart.com/fogger1.html

What would happen if we put one of these in a skimmer?

I am guessing seriously small bubbles and lots of foam....

I know we'd need to solve a couple of problems:
1 - finding one of sufficient power while being made from titanium or plastic.

2 - Will it effect the inhabitants in the tank if the sound waves are allowed to get back to the tank.

Anyway ....thoughts anyone?

Stu

[psimitry]

Originally posted by stugray
2 - Will it effect the inhabitants in the tank if the sound waves are allowed to get back to the tank.

This would be my (admittedly uneducated) concern. I would think that simply because the skimmer would be connected to the tank by way of water that the soundwaves would conduct through the tank and drive fish insane.

[BlakDuc]

Cool idea. Let us know how it turns out! Imagine the shock and awe value with all of those colors coming from your skimmer!

[woz9683]

This Mist Maker utilizes electrical oscillation at ultrasonic frequencies. The ceramic changes electrical oscillation into mechanical oscillation, which creates the mist and water spray. This oscillation also produces negative ions, which help to freshen the air.

This is a quote from another site about the same product.

This product has nothing to do with sound, and it also won't produce bubbles. It just vibrates the surface of the water so quickly that it produces a very fine water vapor/mist.

[stugray]

"and it also won't produce bubbles"

Perhaps the smaller units wont produce much, but before I posted the idea I just wanted to know if anyone else had thought of it so I googled it. Ultrasonic foam fractionation HAS been thought of and tested.

It may require a bigger transducer, but I can guarantee that you could get bubbles from the cavitaion alone. They have ultrasonic transducers that are powerful enough to weld titanium.

I WAS however wondering if you would get any benefit from puttng the ducer low in the skimmer, or if youd need to get it near the top for any effect. Even if it doesnt produce it's own bubbles, it may help break up existing ones in the column. Maybe put it right over the bubble plate facing downwards?

Stu

[stugray]

Oh and the comment "This product has nothing to do with sound"

They most certainly DO have something to do with sound, they are just not optimized to send it out in any particular direction.

These units are built with the exact same piezo-electric transducers used in your smoke alarms and the ultra-sonic proximity sensors and the old Kodak rangefinders used in robot kits. I have played with them myself. I even used to have a TV remote that used the same transducers and it would send my dog running out of the house whenever I used it.

Stu

[stugray]

^

man this forum moves fast.

[salty child 79]

Not sure......but I am almost positive that the device can only be used in a certain depth of water. If it is over like 8" or something like that then it wont produce and fog/foam.

Not sure if that helps but I figured that I would add it.

[Canadian]

There are a lot of things to consider when attempting to use ultrasound in an aquarium application. In physiotherapy we will very occasionally apply ultrasound to a joint like an ankle under water because the non-uniform shape of a small malleolus makes it difficult to ensure appropriate contact of the transducer head and correct angle of incidence.

Just as an example of the complications: the thermal effects of running ultrasound continuously in an aquarium application would obviously be counter productive.

Admittedly, therapeutic ultrasound typically ranges from 0-3 W/cm^2 and we operate it at either 1 MHz or 3 MHz. So any acoutstic streaming or cavitation effects outside those ranges are beyond my understanding.

[bernie lyons]

there were specific piezo-electric transducers made for high frequency tweeters on older speaker designs such as dalquest
loudspeakers . Unfortunately they sucked as far as quality sound is concerned !!!
bernie lyons

[ChemE]

Originally posted by stugray
...It may require a bigger transducer, but I can guarantee that you could get bubbles from the cavitaion alone.

Yes but vapor bubbles which arise from cavitation are incredibly unstable and will rapidly implode once they move into a region of higher pressure (anywhere away from the vibrating element). Rather than a thick cloud of tiny bubbles you'll have one totally destroyed ultrasonic element.

[speartheman]

I wonder how all that steel will work in saltwater I belive they're made only for fresh water

[lpsluver]

Originally posted by stugray
2 - Will it effect the inhabitants in the tank if the sound waves are allowed to get back to the tank.
Stu

The sound waves will not make it back into the tank. There are far too many twists and turns for it to travel that far. The energy would be dissipated.