Air lifting for cleaning pile works (Air Lift)

[KarzanA]

Dears, Hello
I have piles in a project that I want to clean at the bottom (16 m or 53 ft deep) the water may be as low as a couple feet at the bottom or more. There is a technique called "AIR LIFT" that I came across in many piling resources, which I want to utilize.what I need is what will be the typical diameters for those pipes, how much air pressure is needed , at what ranges (minimum depths) the idea works. and any sketches that might be available online
Regards.
Karzan

 

[cvg]

you probably want at least 100 psi and 350 cfm. pipe size and air flow rate will affect the water flow rate you get. call your local water well service company and they can give you the details you need.

http://www.globalsecurity.org/military/library/policy/army/fm/5-484/Ch7.htm

http://www.srk.com/files/File/papers/airlift_testing_in_exploration_coreholes_rlh_final.pdf

 

[KarzanA]

Thanks for the reply,
The problem is that I do not know (and I do not think there is ) any such company here, piling is itself quiet new where I live. I came across this page (

http://www.plantservices.com/articles/2002/12/)

where an empirical equation is given , but it gives me much lower numbers. A concern I have is if the system would work for low levels of water (say I have only 3 ft at the base of the 53 ft deep pile). I think I will start with a 1" pipe for the air and 3" for the water pipe.

 

[Compositepro]

It sounds like airlift is not suitable for your situation. Airlift works due to the density difference between two columns of water caused by the air bubbles. One column is ludicrous the pipe, while the second is inside the pipe with the bubbles in it.

 

[cvg]

ok, the numbers I gave were appropriate for surge / air lift development of a water well (cleaning the screen and removing sand and debris). typical wells are much deeper than your pile. you may not need the same water volume or surge pressure, but not sure since I have not seen this used for piles.

 

[Compositepro]

An air operated double diaphragm pump (AODD), located at the bottom, would probably be most suitable.

 

[Compositepro]

In one of my posts above, ludicrous means water. Darn autospell!

 

[aeoliantexan]

I have cleaned sand from relief wells using 2-inch or 3-inch pipe, 3/4-inch air hose, and a 150-cfm compressor. I use 1/8-inch or 1/4-inch pipe and two elbows to create a U-turn to direct the air upwards into the bottom of the pipe. This creates a venturi effect that helps pull the water into the pipe.

I do not think you will have much success with only 3 feet of water in the bottom. You need to be able to fill the pile at least half full of water and keep replenishing it.

Gravel may need a bigger pipe and more air. Construction airlifts often have 6-inch or 8-inch pipes and a lot of air and will actually remove cobbles.

With only a little water at the bottom, you might succeed with a vacuum truck. Don't try to pump the water that far; slurp it like coffee.

If you are only removing water, not dirt, a mop on a rope works.

 

[KarzanA]

Thanks for the replies

Karzan

Karzan A
M.Sc. Construction Management, MSU, USA
B.Sc. Building Construction, Slemani, Kurdistan

 

[chicopee]

Air lift pumps are discussed in several engineering handbooks such as Mark, Kent and Perry. Also there are articles on three phase flows by such author M. Goit. We used an air lift pump suspended from a crane to remove sludge at the bottom of cofferdams. the 4" eductor was was 40' long and its air line was 3/4". Air pressure in the air line has to overcome the depth of the water, however the air flow will need to be adjusted to insure some optimum performance. the ratio air to water volume is about .17 cu ft to 1 gal. The quality of the bubbles is important because if too big you'll have slugs of air which are ineffective in removing the sludge, so some experiment on the perforated footing will be need to be made. The discharge end will need to have a hose so that the watery sludge can be deposited without contaminating the waterway so we used a Hopper barge with sand pile to filter the sluge and have clean water returned to the bay.