Nozzle design for misting?

[Alan J. Richer]

I've gotten sucked into another project (not of my own..as usual ) ;D

Specifically - mist humidity system for an indoor greenhouse. Want to fab up nozzles that will provide a very small droplet size (so no spitting) under not a lot of pressure. The commercial nozzles for this application, while relatively inexpensive, take 50-80 PSI and I don't think a pump for that pressure is going ot be at all cost effective.

This is not a place where there is shop air or anything the like available, and I don;t want to use water main connections and pressures for the obvious reasons (leaks in the house are a bad idea).

Anyone got a good pointer to a nizzle design page or pages, or can lend a hand on some pointers?

Thanks - Alan

 

[kcmillin]

Alan,
Do you have the pump you are going to use? How many nozzles are you going to have?

I would start with the pump,(this will decide what youre nozzles have to be) go for the highest pressure you can. CFM really is not too important with a mist system. And usually there is air involved as well. If you can, an air pump would also greatly improve your chances of success. then just play around with different size nozzle holes, you can make cheap ones out of aluminun, until you get the desired effect. Make the final size out of brass. The more nozzles you have the smaller the holes will have to be. You may have to drill the holes and then "Squish" the end of the nozzle with a press to squeeze the hole down.

I dont have to much experience with this, so this might be a total wast of time. But I really dont know.

Sometimes I can take a few days of tinkering to get what I want.

kel

 

[shred]

You'll probably want to read up on making gas (butane) jets to get an idea on how to make the teensy holes. I'd look hard at sourcing the nozzles from something pre-existing (the cool-spray misters they use for restaurant patios and the like) and making the rest. Do the commercial ones actually _need_ 50 PSI? 50 PSI is also pretty easy for a little piston pump as well-- check out the Building Fred or other boiler threads for hydro-test pumps-- those can hit 200+ PSI in no time so long as you don't need to move a lot of water volume. It should be relatively easy to adapt one for motorized use if hand-cranking is out of the question.

 

[Ed T]

You can make your own nozzles if your time is worth nothing. You can buy a whole system from www.littlegreenhouse.com for about $50-60.I'm sure you can get parts as well. If you want to run really low presure, you'll have to use very small holes which clog up even if you filter the water. A tiny mineral deposit can do you in. If flooding is a concern (and I'm sure it is if this is indoors) you could use a line pressure system with a flow restrictor to limit the damage if something fails. There are also flow shut off valves that actuate if they sense and "unusual" flow. They are used on washing machines I believe. Making nozzles is not as simple as many seem to think and I think buying them from a company that makes them for a living is probably wiser but maybe less fun. You might also want to check out Spraying Systems. They make more nozzles that you can imagine and have several flavors of misting nozzles. If nothing else, the info in their catalog may help you along. I spent almost 30 years dealing with making nozzles (among other things) and I'd still recommend buying them and spending your time bullet-proofing the rest of the system. Just my two cents worth. Whatever path you choose, good luck with it.

 

[Alan J. Richer]

Thanks for the info, one and all. I would prefer to buy nozzles (and that is a good pointer for them, Ed - thanks!) but the pump issue still concerns me.

Don't want to hand-make a piston pump (not like I can't - just don't want to! ) but not seeing surplus items at a price range to make this job cost-effective.

Need to get a couple of the commercial nozzles and do some tinkering....

Thanks!

 

[ileed]

There are plenty of 12 volt pumps, made for lawn sprayers, for this purpose. Check Northern Tool for many pumps. Try doing a little research. The Web is a great information tool.

 

[Alan J. Richer]

Try doing a little research. The Web is a great information tool.

Y'know, perhaps I shouldn't rankle at this, but as I've been an engineer for 30-odd (sometimes very odd) years in various fields and have used the Web for research for as long as it's existed this seems to me to be a quite unnecessary statement.

I did have a look about - saw lots of data, much of it contradictory and nearly all of it hawking a specific product or another (which I will automatically discount as I've learned the hard way never to trust a manufacturer's representative).

I don't ask unless I can't see myself clear to a good answer - and for every question I ask in a friendly manner on a forum (for my hobby fun - never for my work) I research a few dozen a day on other esoterica.

There is also the personal factor involved here - for every generalized useless bit of Web-based data there is usually someone who's done it himself (or had to do it for someone else) and has hard, empirical data on best practices. That rarely if ever turns up in a search of the web for edge-case data - for rebuilding a Chevy big-block engine, perhaps, but for fan spray design for misting? No.

As for the research I have done for this, I have been to Northern, Surplus Center, pump manufacturers and made a few calls off the Web as well (telephones work very nicely - perhaps you've heard of them?). This is not a matter of being too lazy - but of trying to find alternate paths than the overlarge, expensive, noisy and generally unsuitable items used in mainstream setups where space, power consumption and noise are not an issue.

The operative word here is INDOOR. This is not a situation where I can countenance having some great hulking pump suitable for dewatering the Lusitania's hull running every time I want to do a misting cycle. Pumps and such for greenhouses are easy to get - but they're usually big commercial stuff that is unsuitable for sitting in the lanai and misting the wife's orchid collection.

I'm not sorry for saying this - if you have nothing useful to contribute to a discussion don't.

 

[SAM in LA]

Alan,

20 some odd years ago I installed a misting/drip irrigation system on our back patio.

It was an all plastic affair which utilized our domestic water supply as the pressure source. There were many different misting and drip heads available. The system had an optional in-line filter which I do not think I bought. It also had a battery powered timer.

I believe I bought it from Orchard Supply, this was before there was a Home Depot or Lowes on every corner.

SAM

 

[Alan J. Richer]

Thanks for the heads-up on this item. I've played with a couple of similar systems - can't get a fine enough mist hence my wanting to component the thing out myself.

It ended up out in the back garden on my tomatoes - works great there. The problem with it (other than a tendency to leak at the joints where the barbed fittings are inserted) is a tendency to dribble rather than mist - da wife (gotta love her) wants a fine mist that will raise the humidity in the area rather than dampen the plants.

Sigh...

 

[SAM in LA]

Alan,

Have you considered a stand alone room Humidifier?

I have one that we used in the babies room during winter when he would get the "croup" cough?

SAM

 

[zeeprogrammer]

I'm not sorry for saying this - if you have nothing useful to contribute to a discussion don't.

That response is counter to the principles, ideals, and culture established by the members of this forum.

You might find someone's post to be less than contributory, but they took the time and interest to respond. Further, whether you think so or not, someone else may find a reply helpful.

Perhaps you should follow your own advice.

 

[Noitoen]

:hDe:

TPerhaps you should follow your own advice.

 

[Noitoen]

Here in Portugal to pulverize garden plants you can buy a pump action pressurized container that has a nozzle that can be regulated to spay a fine mist. Since some of the chemicals are "oily" I suppose it could handle machine coolant. I think it's an ideal system and doesn't even need power.

 

[1hand]

(telephones work very nicely - perhaps you've heard of them?).


Pretty much uncalled for.

 

[Kermit]

;D I just love commercial breaks.

Meanwhile, back on topic. I would like to suggest you inspect the supplies painters use.

Sounds like a one or two gallon pressure pot, and a fine needle valve adjustable air brush set-up would fit your needs quite well. Adaptively speaking, of course.

Jim, tell our contestants what they've won! ???
Kermit

 

[Alan J. Richer]

I would like to suggest you inspect the supplies painters use.

Been thinking on that myself - but rather than thinking of using the nozzles or the like been leaning toward a modified HVLP concept.

Large volumes of low-pressure air are considerably easier to generate than high-pressure water or air - and cheap to do so as well. a coaxial nozzle (or adaptation of the old vacuum-cleaner sprayer idea) might be the way to go.

Definitely a thought - and appreciated.

Zee, I will refrain from comment. If you feel the need to further discuss this I suggest that you and I take it off-line.

 

[GailInNM]

Gentlemen.
Please, lets confine the posts to technical issues for the balance of this thread.
Gail in NM
Moderator

 

[Maryak]

Gentlemen.
Please, lets confine the posts to technical issues for the balance of this thread.
Gail in NM
Moderator

Well said Gail. :bow:

I totally agree.

Best Regards
Bob