LP valve?

[CephBirk]

Hello all. I'm working on constructing a homemade airlift for a scientific diving project. Anybody out there have advice on where I could find a valve to regulate the output flow of gas from an LP hose (~135 psi)? I'm not looking for just an on-off valve, but rather something that will help me control the rate of flow coming out of the hose. Probably will be needing flow rates in the 0-40 LPM range. This will be used at depth in seawater, so corrosion resistance is important as well. Any tips on what's out there on the market that could accomplish this?

 

[tbone1004]

DGX Adapter: 1/4-Inch NPT Male = BC Inflator QD Post

This adapter has a 1/4-inch NPT male fitting, used by most compressed air powered tools, and the other end has a standard BC inflator male QD post

www.divegearexpress.com

screw needle valve into airlift
screw BC to NPT adapter into needle valve
Add drysuit inflator hose to regulator

Connect to airlift and adjust flow. $20 and you're good to go


edit: for some reason the link is not working and keeps changing to a media link on here, no idea why. Just go to amazon and search for brass 1/4" needle valve, they're all basically the same. I asked a mod for help so hopefully they can figure out why it keeps force changing to media even when I clink to add a URL

 

[broncobowsher]

Welding regulator. Something for a MIG or TIG welder. They have adjustable flow rates. But underwater use will be a problem. Since you are dealing with highly variable pressures, it won't work.

What you will probably have to do is build something yourself. I would start with an orifice used with some rebreathers. Using a non-depth compensating 1st stage (Apeks with a blanking plug). Maybe the needle valve upgrade. There are limitations to this, the pressure has to stay higher than that of depth pressure. As you get closer to equal pressure, the flow will drop. As long as the flow rate through the orifice meets the sonic flow it will remain the same regardless of depth (until the pressure drops the speed.

OK, I am in a meeting and am butchering this. Just look at rebreather O2 supply for manual rebreathers. The 40 Lpm might be tough, most rebreathers are aiming for about 1 Lpm.

 

[CephBirk]

DGX Adapter: 1/4-Inch NPT Male = BC Inflator QD Post

This adapter has a 1/4-inch NPT male fitting, used by most compressed air powered tools, and the other end has a standard BC inflator male QD post

www.divegearexpress.com

screw needle valve into airlift
screw BC to NPT adapter into needle valve
Add drysuit inflator hose to regulator

Connect to airlift and adjust flow. $20 and you're good to go


edit: for some reason the link is not working and keeps changing to a media link on here, no idea why. Just go to amazon and search for brass 1/4" needle valve, they're all basically the same. I asked a mod for help so hopefully they can figure out why it keeps force changing to media even when I clink to add a URL

Needle valve! Of course! Thanks!

 

[lowviz]

Hello all. I'm working on constructing a homemade airlift for a scientific diving project. ...//... Probably will be needing flow rates in the 0-40 LPM range. ...//...

Need more info as to intended use. Do you want a 'set and forget' valve or something that can be easily adjusted as needed at the moment? Most airlifts will sooner or later want all the gas flow that they can get in order to remove stubborn or mass material efficiently.

It sounds like you are wanting to construct some sort of a delicate airlift dredge. How fast do you want to adjust the gas flow? Have you considered a second air control to 'goose' the lift?

 

[CephBirk]

Need more info as to intended use. Do you want a 'set and forget' valve or something that can be easily adjusted as needed at the moment? Most airlifts will sooner or later want all the gas flow that they can get in order to remove stubborn or mass material efficiently.

It sounds like you are wanting to construct some sort of a delicate airlift dredge. How fast do you want to adjust the gas flow?

I'm looking for a diver holding the end to be able to regulate flow instantaneously. I'm working off this design at the moment:

 

[lowviz]

Thought so. Try this in your design: Google 'Trident LP Hose Air Nozzle Blower'

 

[tbone1004]

Thought so. Try this in your design: Google 'Trident LP Hose Air Nozzle Blower'

problem with those is the diver needs to constantly hold the nozzle open which means it has to be positioned where you can easily reach it and also inhibits mobility of the airlift itself. The needle valve linked is the right answer since it can move a bucket of air, can be connected to surface supply if you need long duration, but doesn't require active input from the diver.

 

[lowviz]

There is no 'right' answer. You give a problem to X engineers and you will get X workable solutions.

I would expect that the critters he is chasing are good at holding onto their substrate. That airgun cannot either free flow or freeze up. I would design it in as a hot-shot momentary 'goose' for a stubborn critter. @CephBirk is designing this thing, I've just suggested another option for his design...

Edit: It would be most helpful if the OP would let us know the collection parameters.

1) Highly standardized collection unit that is willing to miss difficult subjects for the sake of collection reproducibility.
2) Somewhat standardized collection unit that allows for 'cherry picking' of interesting subjects.
3) Mega Hoover that takes in everything, sort it all out later.

 

[АлександрД]

I was unable to find such device on e-bay or other like AliExpress... may be you can find by the pictures
Name of one of such regulators is Licota PB-0007, it is Linear air flow regulator for hand air instruments.

for 1/4" NPT thread.

Регулятор расхода воздуха линейный — купить недорого с доставкой на официальном сайте магазина «Licota»

Купить PB-0007 Регулятор расхода воздуха линейный по выгодной цене в интернет-магазине «Licota». Смотреть характеристики, фото, обзор и описание товара «PB-0007 Регулятор расхода воздуха линейный» в разделе «regulyatory-davleniya-vozduha-i-manometry».

licota.ru

I use it on my Tank-Regulator system for home usage (pumping tires, child balloons, cleaning dust etc.), and with this control valve usage is much more comfortable.
Think, it could be helpfull for you

Also: https://aliexpress.ru/item/1005003417392725.html