Ultrasonic Nebulizer Design with PiezoCrystal (Need Help)

[surrounder]

Hi everybody!

I'm planning to make a nebulizer design.I've a crystal which works on 1.68Mhz(+/-%5) frequency but i have no idea about voltage value.Can anybody help me about this situation.

And how can i design that kind of osscilator circuit?

Thanks in advance.

 

[Sceadwian]

Without the specifications from the maker of your specific transducer we can't help you.

 

[surrounder]

OK i'm going to find it just as soon as. Thanks for your advice.

 

[cowboybob]

1.68Mhz won't work. Way to high a frequency.

Nebulizers (as I understand the term) work in the sonic and ultrasonic ranges.

Scavenge a piezo crystal rig from an audio speaker. Generally speaking, piezo speakers elements ought to cover the frequencies you'll need and are ready to hook up.

A simple 555 astable oscillator circuit (probably with additional amplification) can be the basis for the driver for the speaker element.

Lots of schematics for these can be found the net.

 

[Sceadwian]

Sorry cowboybob, your understanding of piezo nebulizers is incomplete, 1.68mhz is not too high. 2+mhz isn't even too high.
**broken link removed**

There's one unit that's commercial.


Here's a paper written on how to convert a humidifier for use in liquid atomic spectroscopy which lists the frequency at 1.7mhz

Here's a link for a specific piezo transducer for a humidifer specified at 1.7mhz

Older humidifiers/nebulizers may use lower frequencies but they're pretty much obsolete because of the smaller particle size the higher frequency modules generate and their better power handling.

If the unit he's using is modern 1.7mhz is a very safe operating frequency. Power handling is a different story, probably a few to a few dozen watts maximum.

A micro controller is probably a better method to drive such a device, with appropriate bypass transistors it shouldn't be too complicated to drive it.

If the poster does some more Google searches from the results I've posted he should be able to find the volts peak to peak for a common unit, I'm guessing it's going to be in the 15-50 volt range.

Start slow and work your way up doesn't take much over to kill one of these things, and often a lot of power isn't really needed anyways.

 

[cowboybob]

My bad. Only nebulizers I'm familiar with are for COPD.

The thread title did say "Ultrasonic".

Not atomic spectroscopy.

Never mind.

 

[Sceadwian]

Ultrasonic means any frequency over that which is audible by a human being, that's anything over 22khz, there is no upper limit outside of the ability of a transducer to produce it. The atomic spectroscopy link was provided simply because it's one of the first sites that specifically show the frequency used, all it's used for is to atomize the liquid sample into a homogeneous vapor to allow for study, they used a common house hold humidifier element for the experiment.

Higher end nebulizers for medical use (higher end meaning expensive!) use these higher frequencies because they are WAY outside the impedance of sound waves in water which means that more of the energy is transferred to the material. You won't find any modern direct piezoelectric nebulizers that use anything else. What you may be referring to is the type of nebulizer that my stepson has that atomizes his Asthma medication for inhalation, which aren't (until just recently) piezo based but were generally based on a simple air compressor to provide the pressure differentials required for atomization, my father uses a direct inhalation aerosol for his COPD medication never needed a nebulizer.

 

[surrounder]

Sceadwian thank you ver much.I think so i dont need higher voltage values then 15-20V too.I'll post my questions or problems again

 

[cowboybob]

Yes. Thank you Sceadwian.

I know more now that I did.

And that's a good thing.

 

[Sceadwian]

I can't state that for sure surrounder, the voltage's I stated are guesstimations, in order to determine the true voltage you need you'll need to know the impedance at resonance and the power in watts it can handle you can work the voltage back from there.