by Gaxette
T-valve window farm
10:52 am in made from scratch (without a kit), posts with pitcures!, R&D-I-Y, Version 3.0 Modular Airlift Columns by Gaxette
I’ve finally converted my window farm from an inflation needle system to a t-valve system. I stopped using the inflation needle system because I found it to be too unreliable.
window farm
T-valve and check valve
Using two valves: t-valve feeds in air to lift system, the blue check valve prevents water slipping into air pump. I also made sure all tubing dips down to help with water management.
Double dipping tubing
The water tube is sealed to the sports water cap using two plastic o-rings (#6, 7/16″ OD x 5/16″ ID x 1/16″) over 3/16″ ID silicone tubing. There is an o-ring inside the cap and one outside and both are held in place with sealant. Getting this to be water tight was difficult. I ended up doing 2-3 applications of sealant, letting the sealant dry for at least 24+ hours between applications.
Bok Choy in foreground, peas in background
Now if I could just get the plumbing to behave better, everything would be perfect. I’m having a lot of problems with either the system spitting/water rate too high for plants or no water coming out at all. Either the air pump is too high or doesn’t work at all. I’m considering getting rid of my double air pump in favor of two single air pumps for greater control of water flow.
Hi, Gaxette, you need two of the things in this photo! I think they sell them in pet shops and aquarium stores. Put one on each airline and you can dial down the airspeed until it is so quiet that it will spook you! You might (probably) have enough air from 1 outlet to work both columns if you put a y or a T splitter before the 2 valves. . https://lh6.googleusercontent.com/-53frph5yjVw/USZsSmohkrI/AAAAAAAAAXk/i14BZxMQ1IA/w571-h428-o-k/IMG_0003.JPG
Brian, Thank you for the information! You know, I built my t-valve system using your suggestions for how to get enough lift to cycle the water. All your advice has been so helpful; I’m going to go get that right away! I can’t wait to have more control over water flow.
Ok, Gaxette, maybe I am interfering too much in the community. After all, I have never even done windowfarming. Please let others know if the little tap valves work for you. You just turn down the air supply to both slowly until both are working at a nice pace. Then turn off the air and see if they both restart properly. You might have to tweak one more time and then it is set.
Brian
Oh no, I wasn’t saying you interfere, just the opposite. Getting water to lift requires some serious knowledge (and understanding of physics). You’re advice was very helpful. And I will let you know if the extra valves help. (Of course I have to find some first!)
For those using inflation needle system i stopped the air from going back into the resevoir by inserting a valve from a bicycle into the tube. Tightened it with plummer ‘tape’… (there is a long way sometimes to spare parts in some parts of Greenland)
I stopped the air from going back into the resevoir by inserting valves from a bicycle into the tube… (where did my other comment go?)
I’ve just been looking into ways to fine tune the air flow, and would recommend those tap valves, but with one important difference. You want a three-way valve that vents the air rather than dials it down as you run the risk of too much pressure building up in the system and possibly blowing off hose connections. If you do use a vent, make sure it’s between the pump and check valve as you might get leaks anywhere else if your pump is on a timer.
Hope this makes sense.
YOu might find what I have done helpful, It is basic, but the concepts might give you some guidance.
http://our.windowfarms.org/2012/01/06/my-simple-t-valve-airlift-windowfarm/
If you do use manifolds, then make sure you have a release valve to mitigate back-pressure on the pump.
I think people are right about the back pressure thing. Perhaps the best solution is a tub or pipe or aquarium to vent your excess air. Just read the capabilities of your pump. If it is one psi, that max it can do is just over 2 ft deep in water, 2.3 ft to be more exact so put a vent tube 2 ft under in a pipe or aquarium! Then no matter what you do you cannot hurt your pump and you can still use the maximum air possible in your windowfarm. It is an extra inconvenience but probably worth it to some people for peace of mind. Brian