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Sonicator

A sonicator is an ultrasonic device that relies on caviation to emulsify and/or extract substances. This example operates at 28 kHz and has a power of 100W.

Braeden Hamson

Feb 18, 2016
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Feb 18, 2016
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Braeden Hamson submitted a new Project Log:

Sonicator

Holy crap I did it! This was far and away the hardest project I've ever done.

I decided to type up my results to tell you all about this because a few of you helped me get here, but also to just put what I learned out there as another data point for anyone who is going down the same road as I am.
This took 3 months of work, sometimes for 10+ hours a day. A big thank you to Harold Kapp his help was key to making this work. The vast majority of that time was understanding how the heck all of this work, and then machining the actual horn.
But slowing down, what and why? A sonicator is a device that can both extract substances from plants or animal cells by literally exploding them open with a shockwave from cavitation. They can also emulsify two non miscible liquids, like oil and water. This is a permanent mixture that requires no additional chemicals, this is the freaky looking stuff in the cup.

pb39RVZ.jpg

That is a mixture of mineral oil and water, I'd like to note that both of those are clear liquids. The craziest part about this whole device is how it works, It sends vibrations through the horn, which is the aluminum piece shown in the picture. This device amplifies those vibrations until they reach the tip where the amplitude is greatest. That tip then moves back and fourth 28,000 times a second. Or in the case of my particular device 26,500 times a second, this is really important because the device must be in resonance in order to work. If you don't get this right you will get transverse waves within the horn, this is where the horn literally wiggles back and fourth like a wet noodle.
KxQcgBQ.jpg


Of course in real life this is visually imperceptible, however I think you can hear it. While the frequency of the driver is 28 kHz which is out side of human hearing, when the horn has a transverse wave due to it being out of resonance you can hear a fairly loud audible tone. I think this is due to the wave.

mdADooe.jpg

Now the ideal vibration mode is the longitudinal wave. This is where the tip acts like a jack hammer as you can see from my simulation picture. This is what happens if the horn is resonating correctly. To get into the city where the ball park is you calculate the wavelength of sound within the material the horn is made out of. For me this was 6061 aluminum which has a speed of sound AROUND 5000 m/s. Apparently its really hard to know how...

Read more about this project log here...
 
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