Chief Delphi - pic: Art's other cool toy

Quote:

Originally Posted by sanddrag

Well, it'll never be cold enough to do that here, but where do you get such a long lasting supply of compressed air? Surely this thing would empty a tank faster than a compressor could fill it, no?

Right now, the compressor that I am using is rated at putting out 9.0 CFM at 40 PSI and about 7 at 90 PSI, but, the compressor is like 20 years old, so I have no idea what the actual output is. I'd guess that is about 8 CFM at about 75 PSI.

If you were to make a snow gun, you have to make sure that your air and water pressure is about equal, give or take about 5 PSI. Otherwise, you may force the higher pressure fluid down the other hose. I originally tried to use the air at 90 PSI, but when you opened the faucet in the house and heard compressed air coming out, something's wrong! :yikes: Luckily, I have city water (not a well) and I live at the bottom of a hill with a large subdivision, so the water pressure at my house is very high. (It was about 110 PSI before it gets to a pressure reducer, which drops it down to 75 PSI.) If you have low water pressure, I have seen people on the Internet who have used pressure washers to get their water pressure up.

Here is the basics of the design. When a compressed gas is allowed to expand very quickly, it drastically reduces the temperature of the air around it, as it tries to absorb energy from it to get to a higher state. So when the compressed air comes out of the snowgun at the same time as water, the expanding air takes lots of energy away from the water, so the water freezes into snow. Theoretically, if you were to have enough compressed air coming out of the snowgun, it would take so much energy away from the air, that you could make snow above the freezing point. I have seen some ski resorts be able to make snow at up to 38° F.

Everything in my snowgun is made of 3/8" NPT pipe, all available at Home Depot for exactly $24.93. At least it was a year ago when I bought all the parts. If you were to make one, be sure to use the Teflon Tape on all the joints, because any water leaking out will make giant icicles. Here is basically all that it took to make it.

The only thing is that you should buy a ton of end caps where the snow comes out. You may decide to make different sized holes for different weather and temperature. I decided that in order to try to get even more snow out of the snowgun, I would add the 90° tee and drill five holes into the side of the pipe. This would allow the snow to get more air contact when it came out, and would allow for even more water (and hence snow) to come out of the snowgun.

Last year on Christmas, I was only able to make about an inch and a half in about half of my front yard. The temperature had barely reached 27° F, so the snow was right on the edge of the slush/wet snow line. But I have been able to make seven inches once on about 150 square feet in two and a half hours, when the temperature was 7° F.

If you do build one, make sure you check it every hour or so. Otherwise, you may have tons of snow or ice build up on it, which may freeze the gun up. (Or burst your garden hose...which has happened to me three times. If you don't catch it, the garden hose will flood your front yard, and then freeze solid. This happened last year, and as a result I had eight inches of solid ice over a good part of the front yard.)

Quote:

Originally Posted by Jay H 237

Please be aware that adding a snow machine onto your robot is not allowed by FIRST due to possible playing field damage and is also bad GP. :p

What about the Curling + Robots = Sweet game? :p