Sunday, July 18, 2010

Connecting a hose to the helium tank

This sounds like it should have been easy and essentially it is easy .... except it's not. It's easy to know what you want to do but it's hard to figure out the exact parts that will work.

We rented a standard helium tank from a party balloon company with 170 cubic feet of helium. (at over 2000psi. Did you see the movie Jaws? Don't drop the tank!)

On our first launch we wanted to use a hose to connect to the tank but we didn't know what size the connector would be on the tank before we rented it. So, we just guessed and bought some hose parts at Home Depot from the air compressor department hoping they'd work. The ones we bought were close, maybe only a 1 or 2mm off, but they didn't fit. We ended up having the hold the balloon directly on the tank and that meant lying down under the balloon. It was manageable but not particularly comfortable.

So, for the next launch we did some research. It turns out there is a standards body, the Compressed Gas Association, that defines specific size nozzles for each type of gas. I'm guessing the idea is you're less likely to make a mistake and connect the wrong nozzle to the wrong gas if the nozzles don't fit. Also, the nozzles have to be made out of specific materials depending on the type of gas.

Anyway, helium uses what's called a CGA-580 nozzle. It took a lot of googling and searching to find what we were looking for. Basically the people who need to know this stuff already know it from others at their job and that really it's pretty specialized knowledge.

With more searching we found it out there's another standard called the National Pipe Thread standard and this is the standard that the other parts we bought before were on. This is also the standard for pretty much all the parts you might find at Home Depot or Lowes for pipes or hoses.

Armed with that knowledge we finally found a CGA-580 to NTP 1/2inch adaptor. We were a little worried because looking at the picture we saw that the nut is the apart that would connect to the helium tank but the only way the nipple would work was if the head looking part was the part that also connected to the helium tank and that just seemed wrong. Fortunately that is actually the way it works.

From that point we just went to Home Depot and got some tubing that fit and a clamp and put them together.

And there you have it. For our second launch filling the balloon was far more comfortable.

We're still a little bit at a loss for how to fill the balloon and test it because once we disconnect the balloon from the hose we have to tie up the balloon. If it turned out we needed to put more helium in we'd need to untie the balloon which would be a pretty big PITA.

If you know a better way to that part please tell us what it is. We can be reached at teamspaceballoon at gmail dot com.

Tuesday, June 29, 2010

Explore Launch 2 in Google Earth!

Explore our 2nd launch in Google Earth where you'll find the predicted trajectory, actual path the balloon traveled, and key images during the lift-off, flight, and landing of the balloon.

You can download the following kmz file for viewing directly in Google Earth:


or explore right here: