air pressure amount needed, for a shallow water airlift.

[PCola]

Using air pressure to dredge for coins etc. in shallow water (3 to10+ ft) how much air pressure (PSI) is needed? What length/size should your return hose be for max. results?

 

[Dig]

Heres a link to a site where someone was building their own Venturi Dredge! Hope it helps : http://www.spudfiles.com/forums/venturi-dredge-why-does-this-work-t15040.html

 

[georgefrombc]

here another link from anderson detecting as he made one and is shown using it.

http://www.youtube.com/user/AndersonDetecting#p/u/0/r9WcVyIjt5s

 

[Jason in Enid]

Neither of those link are for an air-lift.

You don't need pressure for an air-lift, you need volume. Well, actually, you need enough pressure to overcome the pressure of the water depth but at 33 feet you only need ~ 30 psi.

Airlifts work by the expansion of the air as it goes up a pipe. Air the air rises and expands it pushes more and more water out ahead of it which creates a vacuum at the bottom. I don't have any math for creating them, I just understand the operation. Just remember that you will need floats to keep the expansion tube elevated, as well as a side run to move the lifted materials away and not fall back on you.

 

[the Swede]

...mmm!!!

Me guess this, part of, is THE very reason for me having serious trouble breathing through my 'snorkel' when just about three feet, or so, under the surface of the southern Baltic Sea...!!!

Explains quite a bit, THANK U(!!!), even though it was not the actual topic of mind...

Serendipity, me guess...!!!

Neither of those link are for an air-lift.

You don't need pressure for an air-lift, you need volume. Well, actually, you need enough pressure to overcome the pressure of the water depth but at 33 feet you only need ~ 30 psi.

Airlifts work by the expansion of the air as it goes up a pipe. Air the air rises and expands it pushes more and more water out ahead of it which creates a vacuum at the bottom. I don't have any math for creating them, I just understand the operation. Just remember that you will need floats to keep the expansion tube elevated, as well as a side run to move the lifted materials away and not fall back on you.

 

[thevacantface]

It's also going to depend on the volume of water you are moving, because you will have to displace that much mass

 

[mcscs]

AIRLEFT[size=medium][/size]




http://www.mindspring.com/~divegeek/airlift.htm