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To have a good Cool Steam device !

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greentree

greentree

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Hi guys*
I will make a cool steam device but i don't know how can do it...
I don't know what frequence is good and with what power .
I hope help me...
 

Do you mean Ultrasonic Mist Generator?
Like in this one in the picture...

m005effe.jpg
 
Hi dear kak111*
First : Thank you for your reply and your very beautiful picture !!!
Yes my mean is exactly this ...
I love to make this...!
 

Dear Green tree
Hi
As have seen , until now , i think you should use a piezo electric crystal , with 1.7MHZ driving signal.
Best Wishes
Goldsmith
 
About piezo mist generators...
They use a submerged piezoelectric crystal somewhat underneath the surface of the water to broadcast an ultrasonic beam upwards.
This puts high frequency waves on the surface, where surface tension causes some of the wave crests to pinch off into microscopic
droplets that are propelled into the air, where they float around as mist. It doesn't heat the water, and it doesn't produce water vapor,
which is transparent. They make lots of teeny tiny droplets which, if the sides of your container aren't high enough,
will float outside the bowl and get everything around them very wet. They don't work well if submerged too deeply in the water,
and they don't usually put out a large volume of mist like you'd see in a theatrical production

Some info founded on web

STEMINC - SMIST25F16RS111 - Piezo Ceramic Transducer For Mist Generation

Mist Generation Kit - 2.50 MHz, 320cc/Hr - STEMINC - SMUTK2500RS112

DC Driver for an Ultrasonic Piezo Mist Generator.

**broken link removed**

Ultrasonic Water Fogger-The Mist Maker
 
Thank you kak111.
But when i tried to build it , it does not work . what should i do ? i bought a 2.4MHZ piezo crystal , and when i gave the 2.4MHZ with my function generator to it , the water shaked but didn't steamed . where is the problem?
 

Most likely the problem is lack of power. You need a lot of power (several watts) to generate a mist. The STEMINC piezo kak111 linked to takes up to 25W. Your signal generator isn't powerful enough.

Keith.
 
Piezo transducers have usually very narrow frequency range, where nominal power is delivered.
eg. 2.5Mhz + / - 50kHz, even more narrow for maximum power.
Depending on the device , the input voltage range is 15 ... 48Vrms (= 20 .. 65Vpeak)
and powers are about 5...30W .
Function generator without HF amplifier can not supply sufficient power to transducer .
Have you checked the data sheet values ​​for the transducer you are testing.

Tell me your transducers manufacturer and the exact type, I try , if i can found data on web.

Here you find some data examples ...
Look MIST GENERATION TRANSDUCER´s
STEMINC PIEZO
 
ok!
I bought a Piezo but there isn't any detail because seller said me i just import it !
so please see its pictures for find its detail .:roll:
IMG_0820.JPG
IMG_0821.JPG
 

You need to find its resonant frequency. You can do that with a signal generator, a series resistor and oscilloscope. You could also calculate it (roughly) from the dimensions. For atomisers the piezo thickness is the important dimension. The vibration mode for ultrasonic cleaners usually uses the vibration mode which depends on the diameter.

Keith.
 
Hi*
I did it with 220k resistor and saw that from 25khz the voltage on the resistor was maximum .
so whats its result ?
 

That is most likely the wrong vibration mode. The mode you need will be above 1MHz. There will also be several harmonic resonances that you might see as well but they will be weaker.

Keith.
 

Dear keith
I don't know which resistor is good for find resonant frequency...
or which resistor is good for put series it with piezo ?!
 

I have done it with resistors as low as 50 ohms (simply using a tracking generator of a spectrum analyser) but something like 1k to 10k ohms is probably better. Too low and the Q will be very low (loaded Q).

Keith
 
I do it and saw that the voltage of resistor at 27khz was 90% and exactly at 2.3megahz was 100% so i think resonant frequency is 2.3 megahz . what's your idea ?

green tree
 

Dear keith*
so i can find resonant freq finally:)
what is schematic of this circuit . this circuit have three transistor .

thank you for your guidance
Green Tree
 

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