by Brian White
Air speed, water holdup and bottom reservoir ideas for the T-joint system
12:38 am in Being a good member of this community, Education, energy consumption, Help the project by testing this, How-Tos, R&D-I-Y by Brian White
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
Brilliant! This is exactly how I use my airlift. Plug flow… now I have a word to describe it.
I completely agree with this method of airlift, and with this it really does not matter how powerful the pump.
Thanks Brian! Your work is inspiring!
Melissa
Just a note that I tried big and small T-joints and small seem to be better. The tiny ones (used for joining air pipes for aquariums) may not be faster but the rates seemed more controllable. I also used large ones (something like half inch diameter) with the pipes stuck in in the inside of the T-joiners and there seemed to be a lot more variability in speed. A long plug would go all the way up. FAST! and then there would be a lull in flow and then a long plug again.
So it seems to me that the tiny T’s restrict the air and water flow and this actually helps by evening out the speed of water and air flow. This creates less churn.
Hi Brian,
Thanks for the tip. When I lowered my airspeed the flow increased dramatically. However…. when the timer shuts the system off and back on again, there simply isn’t enough air power to continue airlifting. 2 ways to get things going are a) A quick manual turn of the airpump adjustment knob (max and then back to minimal) or B) Manually blow into the top of the 4 airlifts, the momentum gets all going nicely again.
Downside of both workarounds is, the whole system becomes manual. At the moment I’ve simply increased the airflow so all 4 colomns start on timer.
I wonder: how I can benefit from low airflow whilst benefitting from the timer?
Any thoughts are welcome Regards,
Andrew
Hi, Andrew, I am sorry that the method caused you problems. http://www.youtube.com/watch?v=n3Ariu5wkEQ and http://www.youtube.com/watch?v=9UvWXYHSGNc may help you resolve it. I think the method I used in the post you refer to lowers the pressure before the control valves and the method in the new video’s lowers the speed of air AFTER the valve without lowering the pressure you will obtain.
Also, http://www.youtube.com/playlist?list=PL17DC16567E0712FA&feature=view_all is my windowfarms research playlist. The last video in the playlist is by someone else and it goes into detail about how the bubble pumps work. I think watching it would be helpful to resolve your problem. With the video you refer to, I worried about max pressure damaging the pump but his video suggests that the pump should be ok. (might depend on the type of pump). Brian