Ultrasonic foggers - Whats the purpose?

[mobile]

What is the purpose of ultrasonic foggers? Presumably the humidity within a terrarium will already be high, so I would imagine that a fogger wouldn't add much to it. The only thing I can think of is they would have a evaporative cooling effect, but would need running frequently to maintain this.

 

[mass]

It's good for raising the humidity if your growing outside of a terrarium. As well as the evaporatiive cooling affect.

 

[Av8tor1]

yep, cooling in my application.... and yep, on same timer as lights

 

[mass]

yep, cooling in my application.... and yep, on same timer as lights

Also on the same timer as the lights.

 

[mobile]

In an open room I would imagine that it takes constant running to maintain humidity, but then I would imagine there could be an issue with the room becoming damp. Do you guys not have trouble with cavitation erosion of the ultrasonic membrane when run for extended periods? Presumably, in lower temperature climates these would not be necessary, as evaporative cooling wouldn't be required?

 

[JB_OrchidGuy]

Mobile it also raises the humidity. The guys running these foggers have almost 100% humidity. In Butches case the cool most keeps his helis from getting burned by the lights so they can get as much light as possible. In the case of an open room yes you would need to run it all the time. But most people's grow chamber or rack is covered to hold in humidity.

Personally I think it is a cool effect having a lingering fog in a chamber or terrarium. Neps like a high humidity. There are other ways to do it but the cool must foggers or humidifiers works great without adding too much heat.

And the humidity issue in the house is fixed when you add the GH or other enclosure in the house. It keeps the plaster from getting moldy from high humidity.

 

[Av8tor1]

In an open room I would imagine that it takes constant running to maintain humidity, but then I would imagine there could be an issue with the room becoming damp. Do you guys not have trouble with cavitation erosion of the ultrasonic membrane when run for extended periods? Presumably, in lower temperature climates these would not be necessary, as evaporative cooling wouldn't be required?

cool, i spend a week on vapor cavitation and "psuedo cavitation" in my fluid power class

no, no cavitation damage that I have ever detected.... mine run as much as 18 hrs per day, day in day out...

 

[mobile]

I wonder what's the difference between our fogger, as I have changed two membranes in the past and I didn't run it for anywhere like the duration you do. I found that the membrane pitted and ultimately failed. I don't use it anymore, as I only have a few Heliamphora and have acclimatise them to a windowsill and an open grow shelf. Might have a slight advantage here in Scotland, in that temperatures are never particularly high and night time drops are usually good.

 

[Av8tor1]

I would tend to think its not the formation of the vapor cavities doing the damage, but a result of the energy released when the cavities violently implode during repressurization. Most times vapor cavitation can be distinguished from psuedo cavitation by the location of the damage being on the high pressure side of the occurance.

But why your's suffers from this damage and mine dont (regardless of brand Ive used) I dont know.

fwiw, i only run high quality RODI water in mine....

off topic, but I show this in class.... always good to get the students interested in cavitation
<iframe width="420" height="315" src="http://www.youtube.com/embed/JaNF467OmR8" frameborder="0" allowfullscreen></iframe>

 

[mobile]

That projectile has some serious energy behind it. The water melon explosion is particularly impressive.

 

[Av8tor1]

if you watch the water bottle closely, you will see the cavities implode after being initially formed.... very nice example.