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Does distilled water work with Ultrasonic Humidifiers?

dashman

dashman

I recently purchased an ultrasonic humidifier. When I received it, I immediately tried it out and nothing... I read the directions of course and re-read them a few times. I checked the water level, tried many different containers and nada.

When I got home from work a few days ago, my son who is 12 was playing with it and what do you know... he got mist.

I didn't have time to put it up in my grow room until today. I took the container he used, filled it up with distilled water and nothing.

I was starting to get irritated at this point so I started experimenting with different pots again. I put the distilled water back in the jug so I wouldn't waste it while experimenting. Everything I tried worked until I poured out the tap water and put the distilled water in.

I finally realized it wouldn't work with pure distilled water. So I tried it with 3 parts distilled and 1 part tap and voila, it worked. Finally!

Anyone else have this experience? Is it just the model I have or a general rule of thumb?
 
It's a general rule of thumb. It appears that the process of producing mist is not purely mechanical as I first thought: I experienced the same thing that you did - loading my cool mister with RO water thinking that this would cut down on the amount of times that I had to clean the unit. I then tried it with regular water and the thing worked! Then I placed the mister in the RO water and again, no mist!
I then took some regular tap water and slowly added it to RO water and surely enough, the more tap water I added, the more vigorous the reaction became and the more mist was produced. It seems that the diffuser relies at least in part to an electrolytic reaction and you need ions (dissolved salts) in the water to make it work.
 
http://www.humidifirst.com/faq.html
Q. How do ultrasonic humidifiers work?

A. Ultrasonic humidifiers use a piezo-electric transducer to create a high frequency mechanical oscillation in a body of water. The water tries to follow the high frequency oscillation but cannot because of its comparative weight and mass inertia. Thus, a momentary vacuum is created on the negative oscillation, causing the water to cavitate into vapor. The transducer follows this with a positive oscillation that creates high pressure compression waves on the water's surface, releasing tiny vapor molecules of water into the air. This is an extremely fine mist, about one micron in diameter, that is quickly absorbed into the air flow. Since the mist is created by oscillation, not heat, the water temperature need not be raised. Ultrasonic humidifiers, therefore, can create instantaneous humidity, and don't have to wait for a heating element to boil the water. This precise on/off humidity control is the hallmark of ultrasonic humidifiers. In addition, unlike wet pad humidifiers, ultrasonic units can be of comparatively small size, and still produce significant amounts of vapor.
Click to expand...

My guess is that the dissolved solids form a seed that the vapor molecules condense around to the point that you can see the vapor. Easy enough to test with either a hygrometer or see if the water supply in the reservoir is consumed faster than by simple evaporation.

Of course you could always charge the vapor particles so that the repel each other and won't condense as easily. A method developed for dispersing chemical and biological agents.
 
Now I know. Thanks for the info.
 
NAN: Interesting. So you're proposing that disolved solids act as centers of condensation. If this is what's being proposed, perfectly distilled water with a soluble ionic salt - like table salt should technically be in solution and not act as seeds for condensation. A micron is still quite large compared to a single sodium and chlorine ion. I dunno, I'm not exactly convinced that there's not some aspect of the diffuser that relies in part with electrolitic reactions. What about adding an ionic liquid - like acetic acid. Would that produce a reaction?
 
I use RO water with a ultrasonic fog maker by exo-terra. It works fine for me!
 
Hmmm My guess is that sensor in the reservoir relies on an electrical current to sense when there is water. If the water is too pure, no completed circuit so you have a device that thinks there is no water in it. That being said, I used RO water in mine (walgreens thing) that had one of those sensors for years and it worked fine until about 3 weeks ago. I messed with it a bit and tossed it out. Now I wonder...... lol My ro water is generally around 10-15 ppm.
Andrew
 
I have a theory to present, although I don't have the physical chemistry stuff to judge how likely it is. Could it be that osmotic pressure is involved? Thinking about it more, that doesn't quite make sense - water with a soluble in it should want to attract more water, not repel it. But maybe there's some bizarro ultrasonic effect that I'm not taking into account.
~Joe
 
My fogger has a replaceable disc in it. So if it stops working I can replace the disc to get it to run again! That might have been what happened to your humidifier Andrew. I have heard that if you don't clean them regularly they can burn out a lot. I have never cleaned my fogger and have not replaced a disc yet in 1 year. True RO water will always conduct an electrical current as it's not 100% pure (very close but not 100%). RO/DI (RO/de-ionized) water does not conduct.
 
  • #10
adnedarn said:
Hmmm My guess is that sensor in the reservoir relies on an electrical current to sense when there is water. If the water is too pure, no completed circuit so you have a device that thinks there is no water in it. That being said, I used RO water in mine (walgreens thing) that had one of those sensors for years and it worked fine until about 3 weeks ago. I messed with it a bit and tossed it out. Now I wonder...... lol My ro water is generally around 10-15 ppm.
Andrew
Click to expand...

This what my first thought as well. It does have a sensor with automatic shutoff if the water gets too low. I haven't looked too much into the mechanics of ultrasonic foggers so this was just a guess.
 
  • #11
If a vacuum is being created by cavitation then in essence the water is being vacuum boiled. Some dissolved solids will come out of solution. A NaCl molecule has an atomic weight of 28 vs the 10 of an H20 molecule. Sodium alone weighs in at 11. Then there are other common dissolved solids such as calcium (atomic weight 20).

A major health problem with ultrasonic humidifiers is that some bacteria in the water also gets dispersed along with the water vapor. So some undissolved particles would also get dispersed.
 
  • #12
Weird. I've used only distilled in my humidifier several times with no problems.

Kind of related note; I put my finger in the bubbling water above the disc. Hurt like hell.

Then on accident last week, during a refill, I placed the plastic tank cap down with part of it touching that bubbling watwr again. Afer refilling I noticed it and pulled the lid off, to find it had warped that part of the lid badly and left a burn mark. It smelked like burning plastic too. Those little discs pack a punch!
 
  • #13
Personally, I have used nothing but RO water in ultrasonic humidifiers for years... day after day, year after year.

I believe it has two benefits,
1. Longer humidifier life
2. No white mineral deposits resulting from the mist (a common complaint with ultrasonic humidifier use)

The water level sensor is likely a capacitance water level sensor, they are common in industry
http://www.physicsforums.com/archive/index.php/t-65437.html

just a lil side note... cavitation occurs anytime the absolute pressure drops below the vapor pressure of the liquid in question.
this can occur because of a pressure drop or a temperature increase.

a boat prop cavities due to velocity (Bernoulli's principle, basically pressure is inversely proportional to velocity) when a person gets shot, the bullet causes cavitation damage due to the velocity. When you heat water the vapor pressure point rises until it is higher then the absolute pressure acting upon the container...

this is why you never restrict the flow of a pump on its inlet... the pressure drops and the system cavities, once the cavities reaches the high pressure side of the pump, the cavities collapse and intense heat is then generated

etc etc etc

test on tuesday ;)
 
  • #14
Interesting post, I'm curious to see what happens when I receive mine, which I plan on using fine filtered rain or distilled water.

Av8tor1 - I remember you creating a post about getting sunpentowns su-2000 humidifier.... Did you ever end up with it??
 
  • #15
yes and loveeeeeeeeeeeeee it

best ultrasonic ive ever used!!!!

I show this in class
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/JaNF467OmR8&hl=en&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/JaNF467OmR8&hl=en&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

When the water vaporizes its expands to 1700x its volume

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/wRqYJvtZVJY&hl=en&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/wRqYJvtZVJY&hl=en&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

this is a good one, you see the expansion of the vapor cavities, then their collapse and finally the resultant release of energy (secondary cavitation from the heat generation)

gotta love physics :)
 
  • #16
haha nice. reminds me of the discovery show Time Warp. Good to hear about the Sunpentown.
 
  • #17
Are you positive you're waiting long enough for the base to fill and trigger the sensor before turning it on? The water has to drip feed down and fill the base which can take a long time if you leave that little blue filter box in the base. I just throw those things out since the water I'm using can't get much cleaner anyway.

I have always used R/O and or distilled water in mine. That's actually what the directions in both the Vicks and Reli-On ultrasonic humidifier models from the Pharmacy say to use. In order to keep the disk clean and avoid mineral deposits on the disk. I only threw my old Nep keeping ones out since the modified output tubes were pretty nasty and growing algae inside them but the disks still worked.

My dad uses city tap water in his and you can definitely SEE the output. It looks like white smoke and leaves flakes everywhere, it's pretty awful! Mine is a pure smoky fog and leaves nothing behind but I only use pure water in it.
 
  • #18
swords said:
Are you positive you're waiting long enough for the base to fill and trigger the sensor before turning it on?
Click to expand...

I realize now that my post was misleading. This is not a humidifier, but a fogger. You know the short metal cylinders with an adapter and a plug.

With tap water, instant fog. With distilled water, nothing.
 
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