How To Get Frequency Regulation In A Potency Ultrasound Generator?

I don't think you will get adjustable frequency.

The drive is usually a peizo electric crystal at resonance...which, by definition isn't going to be adjustable.

(maybe someone else will know different?)

Del

Bear with me for a moment, my training has been to avoid cavitation at all costs!

Cavitation is when a liquid changes phase to a gaseous form, and then back to a liquid. The resulting implosion of the gas bubbles "tear" away at the surrounding material, be it a pipe wall, or the capillaries of a plant.

Searches for what you are describing yeilded no tangible results (some hits for variable frequency ultrasound - not applicable).

But I cannot imagine, how that process could be "non-destructive". If that is the case, then perhaps you might look at using a variable "partial vacuum" instead. That is easily done. Or a combination of both. Bring the environment just shy of producing a vapor phase, switch on an ultrasound device until you reach the desired point, and then switch it off.

Just a thought.

Normally, in a pump or valve, you'd want to avoid cavitation. The bubbles formed can damage the internal walls leading to failures or leaks.

Some ultrasonic bath manufacturers produce models that create cavitation on purpose because it can really clean some hard-to-clean items. Soft metals, like aluminum, are not recommended to be used in these types of cleaners. If you're cleaning jewelry, you'd do well to stay away from these types.

As Dell said, most ultrasonic cleaners use a piezo-electric transducer which has a resonant frequency where it is most efficient. Varying the frequency will result in lower cleaning efficiencies.

I think there are manufacturers who use electro-magnets, however. These are really big and heavy ones and their frequency can be changed, I believe.

Thanks all for your comments and contribution, specially to you Vulcan.

Does anybody know any manufacturer of Potency Ultrasound Generators based in electro-magnets?

Try this site: http://www.humidifirst.com/ They produce ultrasonic transducers meant for vaporizing water.

I work for a company that builds ultrasonic cleaning equipment, we do build a multi-sonic generator, and many different freq. generators that are designed for delicate applications. Our R&D team, which is lead by William puskas is now working on a mega-sonic generator that can be used in many delicate applications. The following web site give a great explanation, and has technical pages.

thank you

Bryan

http://www.blackstone-ney.com/index.php

Bryan:

Thank you very much for your contribution.

I will check about the compatibility of your company generators with our needs.

Just keep in touch.

Hi diomin33,

ultrasound for cleaning purpose is only used with water, because the fficiency of the cavitation impulse will be vastly lowered by any other evaporated material that is condensing later or not at all at bubble break down.

Same problem with air dissolved in water: this will prevent proper cleaning, so give the bath an extra 15min runin to remove dissolved air or give it a short boiling before start.

So your extraction process will be influenced by any volatile compound - and these you want to extract.

A better way may be to use pessurised liquid carbondioxide.

If you stay with ultrasound: the generators are free running generators that have no fixed frequency but the impedance of the piezoelectric exciter including the attached water and parts in the water is defining the frequency. The impedance match is bad if no or not enough water is in the bath, this will reflect the power to the transducer and overheat it. In radio-frequency applications a matching network (automatic impedance transformer) would be used .

I never looked into these oscillators but this cannot be a big problem to find a typical electronic layout and analyse it to change frequency.

May be it is a good idea to look also at the higher ferquency units as the bubbles generated are much smaller and can be generated inside biological cells to break these up. Ordinarily used frequencies are 20 to 40 KHz but some units used in LIGA for galvanising microsystems go up to 4MHz.

There is a unit that is used for medical applications to destroy cancer tissue. This is called HIFU , an acronym for high intensity focused ultrasound.

It will kill most or all (?) cells in reach of the high intensity spot.

Have fun

RHABE