Im not awake yet, but some of those droplet size numbers and flow rates dont make a lot of sense to me, Or maybe it just that they dont seem to follow the same pattern as other data I have seen.
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Why? What do you find suspicious?
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In this spec page, the l/h numbers dont make sense in some of the columns. Ive highlighted some of the numbers that jumped out at me. Notice that the l/h number goes up with pressure, but then goes down at 2 bar, then back up again. Further down, the l/h numbers go up as expected all the way across. I think there were a couple of others that looked odd to me as well.
(moved to the next post for better zoom)
Its just far enough outside what I would expect when the pressure goes up steady progression to make me wonder if this is really based on testing, or is someone just copy/pasting from other specs?
I should have posted each image in its own separate post so you can zoom in enough to read it well. I will fix that.
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The other spec sheet you posted is too low a resolution for me to see well enough to be sure, but some of those numbers also looked odd as far as the progression from low pressure to hi pressure. If you could post a higher rez pic or just that image by itself in a single post, that would help. This is the best I could capture.
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These flow rates have different air pressures, and as SU13A is an internal mix nozzle, it follows the rule “higher air pressure → lower liquid flow rate”. So you’ve marked different liquid pressures but with different air pressures as well: 0.7, 1.3, 2.0, 2.7 and 3.9 bars accordingly, I believe this is the reason.
I have a better idea, here is a link to the full Spraying Systems AA nozzles catalog.
At the moment the most interesting positions for me are SU13 and SUE15\SUE18, they have enough flowrates with good air consumption. If we believe in 0.02-0.06 ml of liquid per volume gallon misting formula for 420 liters it gives me from ~8 to ~24 liters per hour liquid flow rate for 1 second misting cycle to put out all the mist. So if these nozzles are able to produce drops at around 50 microns with low deviation I would have one of these. And I believe I would have an external one.
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This is the best mist I’ve been able to get. It is even leave some drops on my arm hairs.
1.5 bar water pressure, 1.7 air pressure.
Here are hang times: https://youtu.be/ISl5nQd16OI
Here is current misting schedule settings for test (2.5 on / 35 off, ): https://youtu.be/-ei3W087E3c
But the nozzle consumes A LOT of air. With this schedule compressor starts every 3 minutes, it means that is looses ~2 bars of pressure during these 3 minutes. 2 bars is 48 liters (24 liters tank * 2 bar). I’ve found that with this pressure settings regulators themselves consume slightly less than 3 liters per minute, round it to 3, so 3 minutes = 9 liters. 48 - 9 = 39 liters. Now let’s calc the actual misting time: 3 (minutes) * 60 (seconds) / 37.5 (seconds, full misting cycle) * 2.5 (actual misting duration) = 12 seconds air is actually flows out. So 39 / 12 * 60 = 195 liter per minute!!! Absolutely terrible numbers. I’ve got the next confirmation I received not what I’ve ordered.
Liquid consumption is also way too high: around 7 ml per cycle, so it gives more than 16 liters per 24 hours, but I think this is mostly because after-cycle dripping. And the solenoid sits as close to the nozzle as possible (the ruler has cm scale):
In the morning I’ve called to the Spraying Systems local representative and his promised me to send some current data about nozzle types\pressure settings for VMD 40 micron as they recently got this data and it is actually possible to ask their lab to do a research for the capable nozzle\settings for 50 micron with my requirements. Not sure if it is fair to ask about such things as I’m not going to buy new nozzles at the moment for sure (on ebay only).
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Oh wow. Yeah, thats way too much air and water consumption for realistic growing. Id say that means these nozzles are putting out too small a droplet still on average if it takes that much just to wet your arm.
Im hoping your idea to use the good caps with the cheaper nozzle bodies works out.
Im surprised you are still getting that much run-on dripping with the solenoid that close to the nozzle. These nozzles dont build up very much pressure compared to the HPA nozzles either, so the tubing should not expand all that much on each cycle - or is that flexible tubing or rigid tubing? Flexible tubing would allow for more pressure build up as far as volume.
EDIT: It looks like you are using standard push fit connectors and tubing, so not flexible. Im mystified. Maybe the solenoid is slower closing than opening? You might be able to tell if you slow down the video and look closely at the beginning and end of a cycle. I can often see how fast the solenoid is opening/closing by timing the frames from beginning to end. On my computer that works out to plus/minus about 17 mili-seconds
Im still going through that Spray.com PDF. Im liking some of the siphon type nozzles, but they all seem to need a little more air than the pressure feed nozzles. Still, no more than Im using now - I think. Need to o the math again when Im less stoned 
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If I put my arm down to the bottom it becomes very wet and looks like with good drops. I think that may be - just may be - the nozzle is too low. I found out that the opposite to the nozzle part of the chamber\lid is also very wet. I intentionally tried to check mist quality at the same side as the nozzle itself, and at least half of the chamber lid stays dry.
I’ve got numbers, by the way, from the representative. They aren’t much useful for me because they used SU11 (round spray) and SU16 (wide angle round spray) nozzles but still interesting:
I have more detailed report with curves as well.
…and I’ve just found a bargain deal with best offer for SUE18B nozzles and for 2050 fluid caps, which is a part of SUE18A and the latter has the same air cap as SUE18B, so I can have both options. Very tempting. Best offer sent, waiting for reply, keep fingers crossed.
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Yes, it is very rigid.
This was my first though. But then I’ve tried to swap solenoids and nothing changed at all (I have different solenoids for air and water lines). I’ll try to check video now.
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Wow… looks like I just got 2 x SUE18B nozzles and 2 x 2050 fluid caps for just $33 in overall including delivery…
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For comparison: with the information from Spraying Systems I told about they’ve sent me an offer. For $140 per nozzle or $465 for 5. 
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Im not surprised. This is why I suggested you do that “dry test” above. Remember i said that the droplets dont bounce off surfaces and the larger droplets wont turn the corner and go up at the end of the chamber nearly as well as the smaller/too dry droplets.
This is also why atomizer harps on having enough nozzles for “good coverage” of the roots. One nozzle, or too few nozzles, often wont work for just this reason.
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Im rushed, but will look at those numbers later…looks interesting though!!
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IIRC he says that about hydraulic nozzles. I clearly remember his words that he had a 700 liters chamber with only one AA nozzle. Of course, he didn’t mention it and I think he was talking about that rotating installation but still. And he talked about 8x4 feet chamber with just two AA nozzles on the opposite sides of a longer dimension, this is why I’ve decided to try one nozzle for the chamber twice as less.
I’ll play with these new nozzles, this is why I’ve decided to have two: if one is not enough then I can put two of them on the opposite sides and use the second pair of solenoids. But I want to fire them not simultaneously to prevent drops collisions. Or - if I’ll get a couple of cheap 1/4JAU bases which I already requested on eBay - it might be just one solenoid at all. JAU are pneumo-automatic setup which opens liquid flow with air pressure, so the liquid part might work without a solenoid at all.
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I am eager to see your next results 
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The same 
Now it will take at least 2-3 weeks to get these new nozzles, hope they send them today.
Don’t even know is it worth to continue any experiments with the current nozzles, at least before I get any results from the new options to compare.
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hehehe I was going to drop this, but since you brought it up… you could try that “dry test” I mentioned above. I am pretty sure that after even a single short 1 second ON cycle, you will see what Im talking about when I say the droplets dont bounce and dont turn corners very well 
Im going out on a limb here and predict that you see a very wet bottom - especially toward the far end of the chamber. Same with the long sides - the lower parts will be very wet - especially towards the far end. But, the top of the sides and the far end will be relatively dry and especially the lid. The end where the nozzle is will be almost completely dry.
Sorry to drone on, and I know you disagree, but I really think you have made a bad assumption with your nozzle placement… I wont pester you about this again
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I didn’t do a special test but I’ve noticed spraying patterns. It is actually pretty wet even on the same side as the nozzle itself, but only from at the low levels. It is pretty wet both low and high on the opposite site, at least with some pressure options (I didn’t check every time I changed pressure).
I will try to use settings to prevent the stream to hit the opposite wall too strong; if you remember the Spray.com catalog they have A, B and C distances; B is the most far point within a shaped stream, after that turbulence is starting, and the C is the maximum stream length with the smallest particles at the end. As I don’t know exactly what nozzles do I have now I can’t set pressure\distance do have C less than my chamber length. But it may worth a try for the known nozzles.
I really don’t want to spraying roots directly. If I do then it is as simple as to put the only one wide angle cone nozzle at the center of the lid and that’s it. The same option works for the guy growing strawberry, he had written about this kind of setup here some time ago. There is even 360 degrees nozzle exists as I found in the catalog.
But it is an assumption only, I’ll test it and if it doesn’t work I’ll do something different
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Thats an interesting idea. That would mostly involve lowering the air pressure?
You may have to do what atomized talked about with moving the nozzles to different places as the roots grow. Up top, or at least higher up early on, then lower once they start to develop.
As I mentioned in my thread - the trick is access. You look like you will be able to get to all sides of your root chamber, so that should make it much easier to do.
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I believe it requires to lower both phases pressure, cause atomization level depends on air amount (~= air pressure) and liquid amount, and liquid amount depends on the nozzle orifice and liquid supply pressure. The problem is that as result it might require too much time ON to generate enough mist. But will see.
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