Anyone ever tried air driven atomizer type approach for aeroponics?

Atomizer

Well-Known Member
microfog nozzles work if you have a dripper system doing the lions share of the irrigation. Fwiw, you can get identical stainless steel ultrasonic nozzles from china for around $18 each ;)
Aeroscience aerotrays (3x3, 4x4 and 5x5) use microfog nozzles + drippers to keep the plants upright. The roots are not much better than LPA and the price tag doesnt include the compressor ;)
microfog roots.JPG
 
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Atomizer

Well-Known Member
Had some free time today so i hooked up the nozzle to show what kind of mist you can expect for your $200-$300. I used 4" siphon height and air at 15psi, 20psi and 40psi respectively. I didnt bother with a timer or solenoid so you`ll have to imagine what a second of mist looks like ;) The ultrasonic resonator tube on the front of these nozzles makes a very distinctive sound at the end of each misting. The tub used in the test is 750mm long x 650mm wide (internal)




For comparison, this is what 5-80 micron mist looks like. The AA nozzle used in this vid cost just under $110 and was running with 6" siphon and 30psi air.
 
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Larry3215

Well-Known Member
Very interesting.

So, were those first three videos using the $200 microfog nozzles or were they the $18 Chinese versions?

Do you have a link or part number for the one in the last video? There is a clear difference.

In the first three videos, all of them have a little hickup or pause right after they start. Is that due to not using solenoids or is it the time it takes for the siphon to get the nutes up to the nozzle or something else?

The last video has an almost instant start and stop with no run-on dripping. I assume thats the solenoids again?
 

Atomizer

Well-Known Member
The first 3 vids are the ultrasonic AA nozzle, its not from china and it didnt cost $18 ;) No solenoid in the test, just a 3/8" airline hooked directly to the nozzle so there is a ramp in pressure at the start and finish but i let it run long enough to show the mist quality you can expect to get at the stated pressures. The last nozzle had a solenoid and timer set to deliver 1 second of mist.
 

Larry3215

Well-Known Member
Thanks, but that doesnt clear it up for me very much as far as which exact nozzles are being compared. Googling 'ultrasonic AA nozles' or 'ultrasonic air nozzles' or 'ultrasonic mister nozzles' returns a lot of possible results, but none of them look quite like what you have there, and the prices are all over the place.

Plus, I have no clue what nozzles or pressure you are using in the last video other than I assume its some type of AA nozzle?

You may not realize this, but you can be very difficult to get specific information from :)
 

Atomizer

Well-Known Member
The comparison is a microfog / aerolife ultrasonic nozzle and a standard siphon fed AA nozzle. The air pressure on the last nozzle was 30psi with 6" of siphon height (as measured from the water level to the center of the nozzle). The difference between the two is the ultrasonic uses a resonator tube that passively vibrates at ultrasonic frequencies to break the droplets into smaller sizes after they`ve left the nozzle, the resulting dense cloud of sub 10 micron droplets doesnt provide enough moisture, its much the same as ultrasonic fog generated by transducers. One of these days i will bite the bullet and cut the resonator tube off, there will be no going back from that but no great loss as its only useful as a paperweight anyway ;) You wont find many folks willing to divulge the specific part or model numbers of the nozzles they use because it usually involved gambling a wodge of cash on a nozzle without any guarantee. The cheap walmart AA nozzles might be worth a look if your on a tight budget or just want to dip a toe in for now. They may prove to be the perfect nozzle...or not. You have to buy one to find out ;) Most AA nozzles can be made to work to some degree but i would steer clear of ultrasonics at least until i test one without the resonator tube ;)
 

Larry3215

Well-Known Member
Ah, ok. I missed your point completely the first time around. Thanks for clearing that up. Im slooooooowly starting to get a beginning grasp on this subject - I think :)

I dont think I am ever going to be in a position to gamble that way on nozzles though - unless I win the lottery :) Hopefully, I can get 'close enough' with the hydrolic HPA system Im putting together.

Thanks again!
 

Larry3215

Well-Known Member
Im trying to get a handle on what to look for, as far as mist quality, when I get my HPA parts put together, so Ive been re-watching those videos, and some others you have posted in the past.

Comparing the ultrasonic at 40 PSI to your nozzle at 30 PSI, it looks to me like your nozzle puts out a lot more mist in a shorter time. Or its at least more dense looking. Both seem to have similar hang times, but again thats hard to tell. I assume thats all mostly due to the difference in droplet size? Other than that, my newbie eye cant really tell much difference.

Im probably never goign to do this, but Im still curious about the details. I would have expected a delay between the time the air starts and the time it takes the water to get sucked up in the siphon, but there seems to be no delay in your system. Do you use a check valve or some other trick to keep the water at the nozzle level, or is it just that fast?

One of the first things I plan to do is run some tests with the nozzles I selected - measure the actual output, shoot the mist into the chamber and see how it looks, etc. However it turns out, it will be interesting :)
 

Atomizer

Well-Known Member
From a flowrate point of view it puts out less liquid than the ultrasonic but looks more due to the wider droplet size range. Its hard to judge the droplet sizes in a cloud of mist, what you may think are 50 micron could be 150 micron or more. To get an idea of size, try to find a piece of 325 mesh stainless steel screen and hold it upto the light, the holes will be around 44 microns. Dont be surprised if you struggle to focus cos 50 micron droplets are a lot smaller than folks imagine ;)
A siphon fed AA can pull water into the nozzle almost instantly so there`s no delay, if the siphon height was a few feet you might see a slight delay but it wouldnt be much. Nozzle response is dependant on the system itself because relays, solenoids etc dont respond instantly so you have to account for the electrical and hydraulic delays as well as timer accuracy and potential mist run on to get the full picture. Setting the timer for 1 second doesnt mean you`ll get 1 second of mist ;) The shortest (coherent) mist pulse i can manage with a pressure fed AA nozzle is 0.3 seconds, its useful to know where the system limits are even if you never use them.
 

Larry3215

Well-Known Member
As soon as I did the math, that became one of my primary concerns with the cheap hydrolic HPA system Im putting together - how short a pulse will I be able to do, and still have it be 'coherent' enough to grow good aero roots? As you say, thats going to be difficult for me to determine visually. The only aspect I can measure is the aprox flow rate by spraying the mist into a bag and comparing the difference in weight. That wont tell me anything about how the droplet sizes vary from start to finish, or their average sizes.

I havent gotten any feed back on that from anyone, beyond the little you have posted about the AA nozzles, so I have no idea how that will translate over to hydrolic nozzles. Thats frustrating to a newbie who is looking for advice on a tight budget, but as you say - every system will be different.

I'll just have to do my best, then grow some roots and see how they look.
 

13elves

Member
Still don't understand how you plan to achieve any reasonably efficient consistency WithOut an ACCUMULATOR TANK? an expensive pump Might work given enough "headroom" before each misting cycle to account for seconds Takes From pump "on" Until misTs And how long Keep spraying second pump Shuts "off",Of coursE, i know, I know, obviously, but Is just you never knoW, right?
 
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