Ok, I’ve done a test Atomizer offered: 0.7 bar water pressure and 2.1 bar air pressure. He offers 1 sec ON x 70 sec OFF but I’ve calculated according to his throughput values and my idea of not pushing the opposite wall and set as 0.3 ON x 12.52 OFF.
Video:
And mist hanging time after the chamber is full:
Tried to make a high res video but doesn’t seem to help:
I have mixed feelings.
On the one hand, those short pulses are not “filling the chamber” on each pulse. Thats why he suggested the longer ON and OFF times I think. Most of the time in the past he suggested that each pulse should fill the chamber.
On the other hand, the chamber does seem to fill up over several pulses. He has suggested both ways in the past at different times. Most of the time he talks about filling the chamber with each pulse - as in his calculations of ml/pulse, daily through put etc. Other times he talks about using the shortest pulse possible, but doing it often. Your short pulses and short off time seems to fit that suggestion. Those two suggestions seem contradictory to me.
Your hang time seems too long. In the past he has said somewhere that a hang time of over 5 minutes meant sub 5 micron droplets - which are too small.
Its hard to tell for sure about your hang time. The camera exposure keeps changing during the time. Plus I cant tell if maybe the lens is getting condensation or mist on it?
If you have one of those cat toy lasers, you might try pointing is down from the top, then put the camera on the side of the chamber so you can see the laser light from top to bottom. Turn OFF the camera light so the laser is the only light in the chamber. That way you should be able to see the mist settle or sink from top to bottom and you can tell if the top has more mist relative to the bottom.
Did you check the hang time with the lower air pressure? It might be those nozzles make too fine a droplets at that higher pressure, but its really hard to tell.
This is weird in a sense of the “growing medium” idea. I mean, we either contain the same medium state, as uniform as we can, and then it is better to have a shorter but repeating more often pulses just to “support” the state. Or we mist much, wait for mist fully disappeared and then mist again. Logically the first option has more sense.
In our dialog Atomizer said that one pulse can’t make anything wet. And even a few can’t, only after several hours a towel should become wet.
I’m the reason of exposure waving: I’ve been trying to find a better way to film mist. The problem in reflections as well as in a filming angle. But I’ve dropped my phone recently so it isn’t water-proof anymore and I can’t just leave it inside of the chamber.
I did but not with this nozzles. I’m going to reduce pressure till 1.4 bar and check again.
I agree with all of that - which does suggest short intervals like you were doing.
Yeah, my chamber is mostly non-reflective - which helps a lot - but then I have bright white roots and bright white pipes, and tubing, which all cause major exposure changes. Thats why I suggested the laser toy. It gets around all those problems and shows off the mist very well.
It sure would be nice if it worked out that .5 bar was a good pressure. That would save a lot of air and compressor run time.
I’m afraid this is a complex problem. I have pretty good water flow rate at 0.7 bar: 9.7 - 10 liters per hour. As this is an external mix nozzle it almost doesn’t depend on the air pressure (in reality it does but just a little). Such flowrate allows me to have shorter cycles to provide the same amount of water. But to atomize such flow rate I need higher air pressure. So I either need to significantly lower water pressure and have longer misting cycles (which mean more air consumption) or have high air pressure. Can’t say for sure what is better, but for the first glance the shorter misting cycles are better in a sense of air consumption: even though my air measurements are highly imprecise as I have only analog gauge it seems that at 0.35 bar it has air flow rate ~51 liters per minute and at 1.5 - ~91 liter per minute. But this require a deeper research at the second glance: water pressure 0.3 bar gives 6.7 liters per hour water pressure, and if we choose 1:3 formula then at 0.9 bar air pressure it probably consume less air… going to do my today’s workout and then will try to use a little math or even some real tests.
If you had a huge air compressor and a huge storage tank - like atomizer seems to have - this wouldnt be a problem. My air compressor is much smaller than yours, so for me its an even bigger issue.
Have you noticed any difference as far as air use to water flow with the internal mix nozzles? Are they better, worse or about the same?
It is a problem for me: currently compressor turning on every 8-9 minutes for 30-50 seconds. It is too often. Its pressure switch configured to go on at 6 bar, and I can’t change this settings or I loose warranty. But I can solve this problem in two ways at the same time:
I need to install an additional solenoid for the main line as even in OFF state the system consumes ~2.7 liters per minute. So if I will do and open it in a second before the rest I believe the air supply lines will have enough time to reach necessary pressure.
I need to install an additional pressure sensor which is already ordered and connect it to the controller. It will give two options:
Sounds like that might work. It would be less expensive than buying all new regulators.
Excellent idea for getting around the pressure switch limits! Adding an additional accumulator tank would help too, but that of course means a longer run time when it does kick on.
Edit: I dont know what pressure switch is on your compressor, but on mine, its easy to open the lid and change the settings. I dont see how they would ever know?
This is what the inside of mine looks like. Its pretty typical of the ones I have seen. Those two screws set the ON and OFF pressures. You may need to find the instructions for the switch to find out how they operate. Or - yours may be very different.
Found instructions
.The lowest cut ON setting for this one is about 3.5 bar, so your idea will allow for a much lower cut on pressure.
It is sealed, so I can’t open it unbreakably 
That is too bad. You would think they dont trust their customers!
All that wasted air just seems wrong to me. Are you sure the regulators are not defective or broken? Im having a hard time imagining any application where that would be acceptable or practical.
Sorry, I’ve got flu and despite I had some suspicion it seems that it itsn’t COVID-19 
They don’t 
These regulators have a parameter “Air consumption: 4.4 L/min (ANR) or less” and they have an exhausting orifice. You can check its catalog here. I have IR2020 model.
Been not good enough to make any changes or tests but I think I have some ideas. Going to move one nozzle a little bit up and add an another nozzle from the other side. I need to buy some T-joints to supply it with air\water.
Tried to find any contacts of the Spraying Systems US representatives but seems that if I write to their main site they will forward my request to my country local reps and I they aren’t much useful honestly.
Wanted to ask about air\water pressure to get 50 microns drops for the nozzles I have (and for something like SU13 I might have in the future). The only option is to call but I don’t feel I can talk to anyone as of yet, I sound more like a squeaky wheel now.
Sorry about the flu, but really glad its not covid!!
My daughter and grandaughter are both sick and isolated at home, and have had us really worried. My granddaughter is the worst, but not really dangerously sick so far. My daughter isnt too bad, so we are hoping this is just a cold that was brought home from school. They still have to stay isolated for a good long time though.
I had forgotten about that specification. So, its a ‘design feature’. 
I still cant imagine an application where that would be practical, and it sure doesnt seem efficient.
Hope you get well soon!!!
Hi, @anon32470837, thank you for caring!
Yeah, I’m almost ok, only rudimentary cough bothers a little.
Are they doing better? I really hope so.
I decided to have a break: both from my working laptop and from my project. Especially taking into consideration recent Half-Life: Alyx release: spent some time in virtual reality
But just sent a request for additional fittings: going to add the second nozzle. And I need to rewrite software to make it more suit for the purpose and add more options.
Btw, I’ve got reply from a Spraying Systems representative. He told that they haven’t got any data about particle sizes but can do research. Not for free:
We really don’t have any specific information like you mention below. We could test the nozzles at various pressures to measure droplets but typically we charge for this and this could run anywhere from 3-5K.
Funny guys.
Excellent news!
They are doing much better - thanks for asking!
LOL! And I thought you were dying!
I find that hard to believe that they dont have at least rough information. Where do they get the data in their PDF??
Oh, this is really funny. They’ve sent me a scan of a document with some data. Like this:
I’ll post more in the next posts to allow to zoom in.
