Hi, I have usually just joined up old tubes to make my windowfarm airlift demo’s and I did not really understand why other people were having problems.  Then I did this experiment today pumping water to 18 ft high with a T joint and 2 ft of submergence.  (I did it). But there was the blocked tube problem over and over.  I had to put detergent in the tubes to help get off whatever grease or coating that new tubes have!  Finally it started working but was still stopping at times.

I think windowfarms need to issue an advisory about this.  So many people had a similar problem and after a day or 2 it went away.  Perhaps detergent is the answer, perhaps washing soda, perhaps dish soap.   A few quick experiments need to be done to find the best solution because it really seems to put new people off.   Thanks  Brian. The new video is at http://www.youtube.com/watch?v=6_88_xUd5Zs

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

I don’t windowfarm (I have an outdoor garden and was just too busy this year to set anything up) but I have played with low pressure airlift for many years and I put up a few videos of how t-joints (outside your reservoir) might be a simple option for some people. I am just wondering if the team leaders have tried t-joints yet?
I am also wondering if the leadership of windowfarms would like to enter my airlift “contest”?
Details are at
http://www.youtube.com/watch?v=lKtB1YKoMxk Basically this is just an attempt to find the limits of the type of low pressure airlift that is used windowfarms. There is a HUGE misconception around that airlift pumps need to have submergence equal to the height pumped. (This is simply not true for the slug flow process that airlifts water in the windowfarms systems). My experience with slug flow goes back to 1983!
I got to 13 ft high with just 2.5 ft of submergence and someone else got to 16 ft. Problem for both of us was we didn’t have enough height at our homes to test going higher! Maybe 20 ft is attainable, maybe 40 ft. We simply do not know!
I acknowledge that this is almost like “pure” research. There is no immediate benefit to the windowfarms project. However, if after crunching your numbers, it were of use in 3rd world countries to pump water from wells, it could really put your project on the map! In any case, this type of airlift is really poorly understood and really poorly communicated to the public. So maybe doing the experiment would directly benefit your project after all. I suspect that someone with an apartment and fire escape has access to lots more than 16 ft of height and can test the true limits of slug flow airlift pumps. Thanks
Brian

http://www.thermopedia.com/toc/chapt_g/GAS-LIQUID_FLOW.html
Shows you some pictures (lower in the page)  and explanations and charts of how the different flow types transport water.  It also has some pretty mean (to me) calculations to help estimate achievable flow rates.  I do not know how well this can transfer to pipes round the 4mm, 5mm, 6 mm size but maybe it does.

Anyway maybe some people could number crunch and see how well it tallies with reality?

Also the how high can it go competition is still in effect.

No prizes but you might be famous on the internet for a day or two. Especially if you get 35 ft high or more pumping in the competition!  Everyone thinks 32 ft is unbeatable  but I am pretty sure they are mixing things up.
Here are the basic rules

Contest rules for unbelievably high airlift powered by puny aquarium air pump

Anyway it is a fairly cheap experiment if you do it. See my video below
Here is my version pumping to 13 ft high (over 3 meters)l

I made another video and basically I ran out of pipe and ladder and because of that I couldn’t pump any higher but I am curious. How high can you go? I went 13 ft but there was no problem whatsoever pumping that high! So, maybe, if you have a 2 story house or an available high place you could find out how high it is possible to go? So the contest rules are in the picture below and in a video
(You might get some extra hints and ideas if you watch the video)
Basically you use your aquarium air pump, and a T joint set at 2 ft below your liquid reservoir height.

Contest rules for unbelievably high airlift powered by puny aquarium air pump

So the rest of the post is from a couple of days ago and has a little different version of the video. (I am too Lazy to write a new post)

I made a new video about the pulser pump and Eileen suggested that a “pulser pump nano” (a smaller version) might be useful. The pulser pump is my little “invention” from over 20 years ago. Anyway, I no longer live near a river so I cannot do a nano. But because of my involvement in windowfarms, I can at least test how high a tiny pulser pump can pump. Today I used the T-joint method and an extendable ladder to go pretty high. With an aquarium air pump and 22 inches of submergence, I pumped to 13 ft high today! I bet it can go a lot higher but thats it for me.
Here is the video (which may be of some use to windowfarmers)

I did a little video today about lowering the airspeed through to windowfarm to vary (and sometimes increase!) the rate of airlift.  Depending on your tubes the rate can be quite slow and still give you good pumping. Check it out because I think it can help people to understand a bit better and to get things right first time.
Anyway here are some pictures that I took out of the video.

2 outlet air flow regulator valve

This is a little aquarium valve and bottom pic shows the adjustment knobs

You can either use it to regulate air to 2 t joints or just leave one open to the windowfarm and have the other one just a bit open to let some of the air escape.

Below is a head for connecting a tube under the reservoir. You might need a bit of gauze or window bug screen in the bottom to stop crud getting into the tubes.

Head for watering plants. Snip off the top and use the "neck" to attach tube

And you also can use this thing for aquariums as a bottom reservoir.

Aquarium attachment for tubing

And finally I am going to show you a pic of the bubble in the tubing.

plug of water

If you reduce the airflow into the t-joint and into the tube, sometimes the water flow increases. This is because the type of flow changes from churn flow to plug flow.

Plug flow can be quite slow sometimes. As the plugs of water rise, it changes from many short ones to a few long ones.

Watch the video to get more information.

Thanks Brian

This is an easily available attachment for pop bottles here in Canada. They are available in garden centers for watering plants.  This means the the entire windowfarm can be made from pop bottles and still get excellent airlift.

Your water tube would go down in a J shape to the t- joint to prevent back flow into the reservoir.

If you cut the “showerhead” top off, you can use an upturned pop bottle as your reservoir for a windowfarm and  attach the water pipe to a t-joint  outside  the bottle  and at whatever submergence you choose.  I think this can make life easier for everyone.

Plant watering attachment for pop bottles

We just got our first windowfarm going, but it was not without a bit of experimentation, and in particular, getting the airlift working. We started by downloading the MAMA v3.0 design, and was eagerly looking forward to our windows going green. However, living in Malaysia we quickly realized that pretty much none of the listed components were available.

We went to the hardware and aquarium shops to find out what WAS available. To make a long story short, we did over 30 design variations and experiments over the course of two weeks, learning LOTS in the meantime, and below is what we currently have. As always, it’s work in progress, but at least it shows some variations that can be tried out.

The major realization I had after failing miserably in the beginning is that the core design principle in a windowfarm is basically “use an airlift to feed a series of water bottles nutrition and water”. Everything else is optional and variable (which it what makes this so much fun!). Here are the major variations we made, to the suspension and airlift. Here is the big picture of what it looks like right now:

There’s a tiny airpump to the left, and we found out that we HAD to keep it on the “low” setting. Too much air will disrupt the flow of water. There’s four bottles right now, and they are not screwed together. Instead the top of each bottle is cut out, and each bottle leads to the other. At the bottom we have a reasonably high and narrow bucket for the water and nutrition. As others have found out having a high pillar of water is key to getting the airlift to work, and this way it’s easy to refill as well. The end goal is to use this single airlift and bucket for the whole window. We’ll see how that works out.

Suspension

We couldn’t find any of the suspension components from the original design, but got real lucky in one hardware shop (Ace Hardware in Kuala Lumpur) where we found a one-foot pot hanger. Our window also has a a metal grille (in Malaysia pretty much everyone has grilles for the windows due to breakin risks, perceived or actual), where three metal bars account for one foot. One bottle also turns out to be approximately one foot. So, put this together and you get what is shown in the picture. One end of the hanger is attached to the grille, and the other is put through a small hole in the cap. We also have a triangle cut out for the water to run out, so it doesn’t go through the hole for the hanger. Now we can easily put it and take out bottles. We also experimented with skipping the net cup for the plant, but I think in the end we have settled for having it in. Then we don’t need to duct tape the whole bottle, so it just looks nicer.

We then have four of these bottles in each line. All in all we should be able to put in a maximum of 36 bottles like this in this single window, and each is easy to put in or take out due to this suspension system.

T-airlift system

The second major problem we had was with the airlift. We couldn’t quite find the components shown in the MAMA version, and there was just too many places where it could leak. A bottle also has too low of a water column to consistently get the airlift technique to work. After LOTS of experimentation with various designs (including using straws for tubing, which was awesome but leaky), and looking at how others have done it, we settled for a dead simple version: the T-airlift.

In the middle of it all is a T-joint. On the left we have air coming in from our airpump. On the right we have water coming in from a 3-foot soft tube. At the top there is soft tubing going up to the plants. We have taped the soft tube to the wall, which makes it straight enough. Because the tube for the water intake has a natural coiling effect, and is quite long, that is what keeps it down in the bucket, so we don’t need to tape it down or anything like that. We could make it even longer to increase that effect. I think that having a reasonably long one also helps in not getting the air to exit that way. Sometimes the air will push evenly upwards and into the water tube, but as soon as the pressure is released by the first water dropping into the bottle line, the air seems to prefer going up rather than out the water intake tube.

This system does not require the one-way valves, or needles, or somesuch, and allows for a high water column and easy adding of water. There’s no air leaking going on since the T-joint handles that quite well. It’s not as pretty as other versions, but this is in our basement (with window to outside, since we have a terrace house), so that’s ok.

So that’s it! Now we want to add more lines, maybe reusing the same airlift, and also maybe experiment with using a solar panel to drive the pump for the ultimate post-apocalyptic-nothing-works DIY experience.