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Ultrasonics

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snowman18:
I'm just a hobbyist trying new methods to reclaim precious metals without the use of chemicals and just recently started experimenting with ultrasonic transducers.

The scum in the foam is palladium which at today's spot price is worth $1894.00 US a troy ounce this is what pays for my toys and parts needed to rebuild them.

What I found interesting is the amount of suds produced from sonification anyhow from research I've found that ultrasonic's has a role in a lot of places in industry.

For my purposes ultrasonics works, assay report from the experiment.

snowman18:

--- Quote from: glort on December 12, 2019, 12:09:41 AM ---
As you have the equipment and Knowledge, I'd like to see some experiments done on oil with regards to lowering viscosity.  I have no idea what would be needed, the power of the transducers or anything else.  It would be good to know if they can change the viscosity of the oil and if so by how much?

--- End quote ---

You give too much credit in regards to knowledge, just a retired country boy with to much time on his hands.

Transducers are available in various frequencies for instance a 28mhz is audible to human hearing, I'm hearing impaired and have to out my ear directly placed onto the tank then only hear a slight hum.

 28khz in terms of ultrasonics creates very large bubbles, when these bubbles implode a shock wave is created.

28khz is not recommended for cleaning tanks used on metals such as aluminum, zinc die cast etc, the larger cavitation bubbles will actually damage the parts being cleaned.

I had some reservations using the more aggressive 28khz transducers as the ceramic comb used in a catalytic converter compared to metal is a soft material.

This led me to think acoustic tiles used in a recording studio sound room and that theory paid off the ceramics absorbed the acoustics that could otherwise have damaged the ceramic comb adding unwanted trash to the concentrated I was after.

A lot of research goes into developing a propeller for submarine use that will reduce cavitation thus making the sub more stealthy. https://tinyurl.com/u4w7low

Cleaning tanks use transducers in the 35/40khz range that produce a much smaller cavitation bubble a transducer operating in this range is not audible to human hearing and is more gentle on the parts being cleaned.

Some examples of transducers used on soft tissue in the medical field.

Medical ultrasound transducers contain more than one operating frequency. The following frequencies are a guide to frequencies typically used for ultrasound examination:

    2.5 MHz: deep abdomen, obstetric and gynecological imaging
    3.5 MHz: general abdomen, obstetric and gynecological imaging
    5.0 MHz: vascular, breast, pelvic imaging
    7.5 MHz: breast, thyroid
    10.0 MHz: breast, thyroid, superficial veins, superficial masses, musculoskeletal imaging.

I do not heat my shop so there's noting going on at the moment, plenty of videos on your tube, keywords ultrasonic, canola oil, bio diesel, emulsification, homogenization, cavitation and sonification.

It a very long but interesting journey.

And don't forget to use google scholar from some interesting searches this will give you access to many articles from higher education institutions.

cobbadog:
Heating my tank before use makes it far more effective. When I first set it up after changing the water and detergent solution I must run it for around 10 minutes to, in their words, "de gas" the solution.
My transducers run at 36.7kHz and can also be switched into a 'sweep' mode where as the frequency varies up and down so not to form any 'dead spots' in the tank.
One very effective way to test your transducer is so simple. Switch the system on and have it running. Then dip a strip of aluminium foil in the tank for about 10 seconds and pull it out. You should have perforations through the foil.

WARNING, never put your hand in the tank when switched on is what my instructions say. Now that is like waving a red flag at a bull, why do they say this?
Answer is because apart from killing your flesh if left in too long it also bites like grabbing a HT lead on a good strong magneto, it hurts, I know.

mike90045:
Mhz frequencies are radio waves.  There is no "transducer" unless it's a channel crystal in a holder or a SAW filter

Khz frequencies are closer to Audio, with 20hz - 20Khz being typical Hi-Fi gear, 25Khz generally being the lower end of the ultrasonic range, and a couple Mhz being the upper end.   AM radio roughly covers 0.5Mhz to 2Mhz, above 2Mhz, you are in shortwave radio.

cobbadog:
I went looking for the schematics on my machine. It does have 2 very heavy transducers that sit on the bottom of my tank and are connected to 2 generators that sit on the shelf via a metal braided cable.

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