So far I have been using 1 and 2 foot acrylic tubes to try out different nozzle types, acrylic welding techniques, and liquid bubble mediums. Now that I’ve selected my nozzle (a 1/4″ coupler that joins the 1/8″ vinyl tubing in polycarbonate) it’s time to scale up to full six foot tubes.
Although all of my calculations told me that everything should work with a six foot acrylic tube, you never really know if something is going to scale up correctly until you try it. For example, here is a list of possible problems with scaling up (ordered by probability):
- The air pumps, which are rated to a max pressure of 350mmHg (basically meaning they can just barely blow a bubble into a column of mercury 0.35 meters high, or deliver 6.7 psi), won’t actually achieve their rated pressure, and be unable to blow a bubble into a 6 foot high column of water (4.7 meters of water is equivalent to 350mmHg…but still….)
- The bond holding the nozzle and bottom of the acrylic tube which worked fine for 1 foot of water would spectacularly fail when loaded with 6 times the pressure.
- The Acrylic column won’t be able to support the water pressure, and will burst. (Even 1/8″ acrylic is relatively strong, if brittle, so I wasn’t really worried about this one…)
- The cyclic pumping, combined with flashing RGB LED’s would interact in a heretofore unknown way to produce fusion, a la Chain Reaction (1996).
Fortunately, everything worked just fine. What does an air bubble look like rising thorugh six feet of water? I’m glad you asked. Watch this video:
Very impressive project. What did you end up using for your pumps? I wouldn’t think that your ordinary aquarium pump would last very long if you’re turning it on and off so much.
I am using these 12v surplus air pumps by KOGE
P/N: KPM27H. So far I have had six pumps cycling for three weeks and five lasted for sure (one broke, but it was before I put a tube of water on it, so the air pump part may have been broken already, I had just listened to make sure the motor turned when I set it up…) So I’ve bought several extra pumps and am connecting them with plug in jacks so that they can be replaced in the field relatively easily.