by Brian White
2 (or 3) airlift columns from a single outlet air pump! Works!!!
7:33 pm in Being a good member of this community, Education, Getting Started, Help the project by testing this, How-Tos, International, Materials and Resources, pumps, questions, R&D-I-Y, Uncategorized, Water flow by Brian White
Windowfarms recommend a 4 outlet pump but many people already have a 1 outlet pump and probably would like to use the one they have. So here I have a video about a method to split the air stream to work 2 or more columns. If you just split the air with a Y or T splitter (even if both airlift tubes are exactly the same), the air will “choose” one tube (or the other one) and then all or most of the air will go up that one with zero or almost zero airlift happening in the other one. This is because the “starting pressure” is higher than the “running pressure” for any airlift pump. So whichever one starts first will probably stay running really well at the expense of the second one (which will be either really slow or not running at all!)
The method I show to prevent this is to throttle both of them. In the video, I use little “taps” to tighten and restrict the airflow to both sides until both sides run. AND stay running! For this to work, both airlifts should have similar submergence (but they do not need to go to the same height). You might also be able to see from the video that you can have one going a bit faster than the other. So possibly, you can supply more water to some plants when they are big while in the other airlift supplying just a little to them because they are tinier.
There are other methods too but this one should be easy to do and to adjust.
2 airlift columns from a single outlet air pump!
I only did 2 columns because I didn’t have enough tubing to show 3 working.
3 columns might work in my case (my pump is an old aquarium pump that I found dumped on the side of the road so it is probably not such a good model)
Update 2nd Jan 2012. 3 columns works too but in the case of my pump it is the limit. Video Jan 3 2012. 3 airlift tubes working from a one outlet aquarium bubble pump
Youtube now allows you to edit videos so if I am not too busy, I will “upgrade” the video (and this post) over the next week or 2 and show methods to measure the flow or at least compare flows under different conditions too. Brian
Thanks, Brian for putting this out there, I am just starting and need to set up. Will let you know what comes of my trials. Be well and Happy New Year.
Just a note that I found some more tubing and rearranged things to try 3 t-joint airlift tubes working from the single outlet pump and it worked too! (Too dark to try a movie but can do one tomorrow).
I think that is the limit with this particular pump. It sure was neat watching the water “plugs” slowly snake up the tubes. (I didn’t want to cut any tubes for one little experiment so some were much too long) Very Quiet and no need for a silencer.
So, I guess it depends on your pump. Some might be able to work only 2 airlift tubes, some 3 and some 4.
Submergence of the t-joints was about 16 inches in this case. Notice that in the 3 T-joint version, I used 3 different types of t joints! They all worked but the one with the blue silicone air tubing bringing up the water did not want to start. (Probably the tubing is a little narrow and a little new and got airlocked more easily). This might clear up after a period of use as the “wetability” of the tube increases.
Brian
I currently have 2 airlifts running on a single 3 watt single output pump, I have a flow valve on each output from the T valve to control the flow to each tower, essentially a ghetto manifold.
I would suggest a proper manifold once you start using more than 2 columns on a single pump. Based on how much I have to reduce the flow to each line, I think a single pump could run 4 columns.
I am working on my 3rd column and can swing back with an update once it’s done.
Hi, Jesse, have you pictures? I don’t know what a ghetto manifold is. I did a new test with 3 t-joints working from the single outlet pump and it worked too. (Mine would not work 4 columns) it was pretty much maxed out with 3 columns. But that just depends on your model of pump. Brian
It’s using a t-valve at the pump with a flow valve attached to each line to control air to each tower. It is connected to the airlift with a t-valve.
All tubing is the normal airline style, some is black, some is clear.
The flow valves are throttling it almost to the point of stressing the pump’s diaphram, so I would think it could support at least one more tower, if not a fourth.
It is an Eco AIr Plus 1 3watt 1.7PSI pump
I have one bottle so far for the third tower.
Here is a pano shot.
http://i27.photobucket.com/albums/c181/playonpro/photo.jpg
Aquarium Manifolds look like these:
http://www.aquasythe.com/images/SSairmanefolds1.jpg
I basically made on by using a T-Valve and adding a flow valve to each outlet.
Viola! Ghetto Manifold, as I call it.
I suppose you could use 3 Tvalves and a flow valve on each line to equalize the air pressure accross all lines…..or just spring for the quality manifold.
Hi, Jesse, that sounds good. I used a X joint or a cross to split one air into 3 and put the flow valve after that so almost the same thing as you did. Your jpg I know what you mean about stressing the pump (but didn’t want to add another complication until people digested the first bit!). I think we need a way to release pressure. I was going to have a split to tube going down in water (a bit deeper than your submergence) before the splits. That way, if the air to the airlift is less than the pump output, the excess can escape without damaging the pump. I will do a diagram later.
If I am in the mood, I will do this tomorrow in video and everyone can see what I mean.
Thanks very much for your input.
Brian
I was gonna just try slightly opening a valve on a manifold once i get one, but I’m interested in this pressure release system you described. If could be better and only release pressure when required, rather than just being an air leak
It could be cool if it could be made into a little module, like a tube into a pill bottle with a little water in it. Of course, that’s just a crude idea, the actual specifics would need to be based on a few factors, like airlift height, water depth(pressure), etc. But sounds like your idea there could be easily adjusted by dialing in the water depth to balance the pressure with your airlifts/pump.
I might give it a try, if I do, I’ll post, but I needa get two more towers up for now.