Pneumatically positionable Air Cannon

[rokenboker]

This is how a pneumatically positionable air cannon could and should be built. I would recommend using a 1' x 1/4" bore pneumatic and a piece of PVC pipe. !!!NEVER USE PVC PIPE FOR THE STORAGE TANK AS IT WILL RUPTURE. PVC IS NOT DESIGNED FOR PRESSURE NO MATTER WHAT THE LABEL SAYS OR HOW MUCH PRIMER AND GLUE YOU USE!!! Next, use a compressor tank, at least 7 gallons, AND made of metal, for your storage tank. !!!MAKE SURE YOU KNOW THE PRESSURE RATING FOR HOW MUCH IT CAN HANDLE!!! Next you will most likely need some fittings, depending on The tank, a pressure gauge, couplings, 2 ball valves, a sprinkler valve; I would recommend Rain Bird; MINIMUM of 3/4"; you can get these @ LOWE'S, pipe clamps, 3/4" hose MINIMUM, hose fittings, and yes PVC pipe. Put it all together and fill up your METAL tank, make sure the pressure gauge is on it and fill it up to the maximum the tank is rated for and the compressors can put out. IF YOU ARE USING 1 ROBOT COMPRESSOR, YOU MUST, MUST USE AT LEAST 2, THERE WILL BE TOO MUCH STRESS ON THE 1 IF THAT IS ALL YOU ARE USING. Test w/ the ball valves. Put one ball valve on each end of the tank, 1 so you can remove the tank and leave air in it, and 2 so you can test the cannon. Yes there is a minimum working pressure on the cannon and it is PSI. Now once you have the cannon working w/ the ball valve, take off the one closest to the cannon and replace it w/ the sprinkler valve. NOTE: you MUST use a power transformer to make 24VAC for it to work at it best, it will work w/out the transformer, but just not as well, trust me you'll see, and hear the difference. Wire the sprinkler valve to a SPIKE and test it, OUTDOORS, as it will be VERY,VERY,VERY LOUD. Now to hook up the Festo valves. Each Festo valve has Four, 4, ports on it. I will give you the URL to see the diagram. http://www.festo.com/INetDomino/file...TValveAssy.pdf So, plug the tube coming from te compressor into port "1". On the SAME solenoid, plug the tube coming from the bottom of the pneumatic into port "4", plug the tube coming from the top of the pneumatic into port "2". Now on the SAME solenoid plug a tube w/ a "T" fitting on it into port "3", a other tube into the "T" and going into port "1" on the other Festo solenoid, and a tube into the "T" going into port "2" on that second solenoid. Now you are done test it and send me a message if it works or does not and I will be happy to help you w/ the setup. In total, you will need 5 SPIKES, the 2 hooked up to the compressors both need their own 20 AMP breakers. The SPIKE hooked up to the sprinkler valve MUST have a 20 AMP breaker. And the last two SPIKES can have a fuse in them. Hook up the 2 SPIKES w/ a "Y" cable to PWM 8. And hook up a pressure switch to DIGITAL I/O 18. !!!HAPPY LAUNCHINGS!!!

[vivek16]

You obviously have a lot more experience with this than me but I would recommend using abs plastic for the barrel.

-Vivek

[ATannahill]

im interested as to why you posted this, many things you describe are against FIRST rules, especially the things you say not to do. but welcome to CD and enjoy yourself

[DonRotolo]

Originally Posted by rokenboker

This is how a pneumatically positionable air cannon could and should be built.

It appears somewhat arrogant to use the word "should". Also, I am unsure how the term "pneumatically positionable" is related to your comments.

Originally Posted by rokenboker

fill it up to the maximum the tank is rated for.

No, it must never be filled more than the "working" pressure - going right up to the maximum is dangerous. A much safer value is 75% of the "working" rating.

Originally Posted by rokenboker

The SPIKE hooked up to the sprinkler valve MUST have a 30 AMP breaker.

A spike relay module is rated for 20 Amps maximum, find another way to switch the sprinkler valve, or be prepared to burn out a lot of spikes.


While I can appreciate your eagerness and enthusiasm to share what you have learned, it is important to understand that what you write will be read by people with less experience. Any form of stored energy, such as compressed air, can be dangerous. Some of the practices you promote are incorrect or dangerous, and it's possible that you can be held responsible for any injuries resulting from following your instructions.

I am not writing this to bring you down or make you feel bad or dumb. Instead, I want to share some adult perspective. As an engineer, you ARE held responsible for the safety of your designs, and so you are taught early to be darned sure it's right. Imagine missing a decimal place when designing a bridge or building - and then it collapses. In the litigious society in which we live, one needs to exercise caution.


Don


PS: Please use the default font for postings, it is so much easier to read.
.

[cdennisxlx2]

Originally Posted by rokenboker

In total, you will need 5 SPIKES

There are plenty of other ways to do this with out using so many relays

and i completely agree with Don, anything you post on here is viewed by people of all ages and they usually have access to their teams supplies. I can see a few getting really eager and trying to build this and really injuring themselves or others. I'm not trying to douse your enthusiasm ether but safety should be at the top of your mind before posting a project idea, that includes looking at power ratings, possible problems, and the fact that some students can be vary impressionable.

Also formatting can be your friend, or your enemy......